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1 Amphibian and Reptile Research on Coldwater National Wildlife Refuge, Mississippi Final Report to Becky Rosamond Dahomey, Coldwater, and Tallhatchie National Wildlife Refuges P.O. Box 1070 Grenada, MS 38902 From Joseph C. Mitchell, Ph.D. Mitchell Ecological Research Service, LLC P.0. Box 2520 High Springs, FL 32655-2520 28 December 2011

Amphibian and Reptile Research on Coldwater National

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Text of Amphibian and Reptile Research on Coldwater National

Final Report to
P.O. Box 1070
Grenada, MS 38902
P.0. Box 2520
Lesser Siren (Siren intermedia) in Coldwater National Wildlife Refuge …………….… 15
Snake Populations in Coldwater National Wildlife Refuge ……………………………. 21
Freshwater Turtles in Coldwater National Wildlife Refuge ……………………………. 30
Management of Amphibians and Reptiles in Coldwater National Wildlife Refuge …… 36
Appendix 1 – Checklist of amphibians and reptiles of Coldwater National
Wildlife Refuge ………………………………………………………………………… 38
Appendix 2 – Chronology of management actions and field results for 23 wildlife
ponds on Coldwater National Wildlife Refuge ………………………………………… 40
Appendix 3. Summary of frog morphometrics from Coldwater NWR …………………. 63
Appendix 3. Siren intermedia tagged with PIT tags at Coldwater National
Wildlife Refuge …………………………………………………………………….…… 66
Executive Summary
The management actions in the wildlife ponds on Coldwater National Wildlife Refuge create a highly variable and dynamic environment for amphibians and reptiles. Some ponds contain water for long periods of time and others briefly. Managed ponds have different wet/dry cycles than unmanaged ponds . In addition, control of willow invasion by chemical and mechanical means represents levels of perturbation that may affect amphibians. This report summarizes three years of field investigations on these animals in this dynamic environment.
Total amphibian species richness for the refuge was 12. Species richness among ponds ranged from 2 to 10; modal number of species per pond was 4. Number of frog species ranged from 2 to 10 per pond. Two species of salamanders were encountered: Siren intermedia and Notophthalmus viridescens. Average number of species in treatment ponds (4.33) was nearly identical to the average number in notreatment ponds (4.25) and not significantly different. Number of tadpole captures per trap night in minnow traps (a measure of relative abundance) in treated ponds (0.722) was slightly higher than captures per trap night in notreatment ponds (0.594) but the difference was not significant. Analysis of body size relationships in Leopard Frog samples obtained during the same sampling period showed that disk and herbicide treatments do not directly affect body sizes and development of this species. The variable responses to changing water levels by reproductive adult amphibians create the complex interplay of management treatments (mostly drawdown schedules) with water levels, natural water loss from evaporation, frog responses to water dynamics, species larval developmental periods, and food availability from pond flora. The primary conclusion is that frog populations apparently have not been adversely or directly affected by management treatments of disking or herbicide applications.
Siren intermedia were captured in 14 of the 23 ponds included in this study. Siren ranged from 92 mm to 285 mm SVL and 130 mm to 397 mm total length. Number per trap night ranged from 0.006 to 0.133. These salamanders aestivate in the bottom of ponds that have dried by forming cocoons 8 cm or more deep. Disking these ponds may be a primary source of mortality. Thus, an important management consideration is disk blade depth. Shallow disking may result in less mortality.
The known snake fauna consists of 9 species and all ponds are occupied by at least two or three species. Three species (Nerodia erythrogaster, Nerodia fasciata, Nerodia rhombifer in increasing relative abundance) were the most likely-encountered snakes in each pond. Mud Snakes (Farancia abacura), Graham’s Crayfish Snake (Regina grahamii), and the Mississippi Watersnake (Nerodia cyclopion) were the species least likely to be encountered. The Western Cottonmouth (Agkistrodon piscivorus) is also uncommonly encountered on the refuge but the fact that this snake is venomous and potentially lethal means that persons working on the refuge should take all precautions when walking along banks and in shallow water. Snake capture rates
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were extremely variable among ponds and trapping sessions. As with amphibians, snake populations on Coldwater NWR do not appear to be affected negatively by disk and herbicide management treatments.
A total of six species of freshwater turtles were encountered on Coldwater NWR (Table 4.1). They were found to occupy 9 of the 23 ponds studied. The most commonly captured species was the Red-eared Slider (Trachemys scripta) which occurred in all 9 ponds. The turtle fauna on Coldwater NWR is a transient one because each species migrates to the ponds from local source populations and returns to them when the ponds dry out. Management actions, such as disking and application of herbicides, will have little to no effect. Grass mowing, however, may harm individual turtles by crushing them with the mower or being cut by the blades. Adjusting blade height can be evaluated and adjusted to avoid killing turtles on land.
In general, the herpetofauna of Coldwater NWR responds to the varying hydrological conditions in the wildlife ponds by moving among those with water as needed for reproduction and thus creates a dynamic interplay of these animals and the fluctuating environments in these ponds. The use of disking and herbicides for management of invasive willow do not appear to have adverse affects on the amphibians and reptiles on the refuge.
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Introduction
Amphibians have become well known as sensitive indicators of environmental change. Numerous studies have demonstrated that these vertebrates respond negatively to agrichemicals (e.g., Bridges and Semlitsch, 2005), UVB radiation (e.g., Blaustein and Belden, 2005), and disease organisms (e.g., Rothermel et al, 2008). The sensitivity stems primarily from the fact that amphibian skin must remain moist for gas exchange. Chemicals dissolve in water (the universal solvent) and pass readily into blood and cells. The biphasic life cycle of most amphibians places each individual in contact with aquatic as well as terrestrial stressors. Adults require water in which to lay eggs and the aquatic larvae must have water for variable lengths of development, some of which are over a year in length. Thus, the hydrological dynamics of ponds such as those on Coldwater NWR represent a critical component of population persistence and survival.
The management actions in the wildlife ponds on Coldwater National Wildlife Refuge create a highly variable and dynamic environment for amphibians. Some ponds contain water for long periods of time and others briefly with different wet/dry cycles. In addition, control of willow invasion by chemical (herbicide) and mechanical (disk) means represents levels of perturbation that may affect amphibians. This report summarizes field research intended to ascertain the effects of these management actions on the amphibians in the wildlife ponds on Coldwater National Wildlife Refuge.
Materials and Methods
The primary method used to obtain quantitative data on the amphibian populations in the wildlife ponds on Coldwater National Wildlife Refuge was standard minnow traps (GEE minnow traps, Memphis Net and Twine Co.). During each field session, a set of 10-20 traps was placed in shallow water (when present or deep enough) with enough room for air breathing vertebrates to reach air in each study pond. The funnel opening of each trap was enlarged to about 3 cm in diameter to allow capture of adults and large tadpoles. Where possible, I set 20 traps per pond. In some sessions, water levels were too low to accommodate 20 traps; 10 traps were used in most of these instances. Traps were operational for a total of 40 trap nights per pond but in some trips the number of trap nights was limited to 20. These sessions usually occurred when large numbers of captures occurred with this sample size that allowed comparisons without having to trap for longer periods. I counted the number of individuals of each species caught in each trap during each session. Numbers reported in this study are number per trap night. Total species richness for each pond also includes species identified by direct observation and male vocalizations.
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Many individual amphibians captured were measured and weighed. Standard measurement for adult and juvenile frogs was snout-vent length (SVL) and total length for tadpoles. Many were also weighed to the nearest gram (adults and juveniles) and 0.1 grams for tadpoles. Comparisons of adult and larval frog samples in the study ponds are provided in this section of the report. Measurement data for Lesser Sirens is included in the Section 2 devoted to this species.
Treatment ponds were identified as those that received at least one disking and/or herbicide application during 2009-2011. I coded pond L as no-treatment because it was disked in 2008 but had no treatment in the three years following. No treatment ponds received no direct management during this period. The result was samples of 15 and 8, respectively.
Results
Species Richness and Relative Abundance Among Ponds
Table 1 illustrates the species occurrence among 23 ponds studied on Coldwater National Wildlife Refuge during 2009 to 2011 based on minnow trap results and incidental observations. Number of species ranged from 2 in ponds A, H, M, and U to 10 in pond R. Modal number of species was 4. Total species richness for the refuge was 12.
Number of frog species also ranged from 2 to 10. Several species of frogs with 6 or fewer confirmed occurrences are probably more widespread in the pond complex. The distribution of sampling periods in March-April, June, and September may have allowed species with short breeding periods, such as Gastrophryne carolinensis, to be missed in some ponds. The lack of species occurrences in some ponds does not mean that they do not occur there. It is likely that all species of frogs occur in all ponds but at different times due to hydrological conditions in different seasons.
Two species of salamanders were encountered by the minnow trap method. Siren intermedia were captured in 12 ponds (Table 1.1) during the times those ponds held water at least 10 cm deep (deep enough to allow minnow traps to be effective). More details of the trapping success and body size relationships are provided in Section 2. Only one Notophthalmus viridescens was captured during the entire study in pond J. The dynamic hydrological cycles of most ponds and the fact that all the ponds dry occasionally may be the limiting factor for this species on Coldwater NWR, at least in the pond complex.
Ponds receiving disk and/or herbicide treatment include B, C, D, E, F, G, H, J, K, L, Q, S, T, V, and W. Ponds receiving no treatment include A, I, M, N, P, PP, R, and U. Pond U was included in the no treatment sample because all tadpole captured occurred before disk treatment in 2011. Average number of species in treatment ponds (mean = 4.33+1.23, 3-8, n = 15) was nearly identical to the average number in notreatment ponds (mean = 4.25+3.11, 2-10, n = 8). The difference is not significant (t = 0.927, P > 0.05). Number of tadpole captures per trap night in
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minnow traps (a measure of relative abundance) in treated ponds (mean = 0.722+0.855, 0-3.33, n = 15) was slightly higher than captures per trap night in notreatment ponds (mean = 0.594+1.154, 0-3.38, n = 8) but the difference is not significant (t = 0.760, P > 0.05). Pond treatment appears to have no effect on species occurrence or relative abundance of tadpoles in ponds on Coldwater NWR.
The data on frog morphometrics (size and mass for age and sex categories) and mass vs body size relationships are summarized in Appendix 3.
Hyla cinerea (Green Treefrog) tadpole.
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Table 1.1. Species of amphibians recorded in each pond studied on Coldwater NWR during 2009-2011. Letter codes: X = caught in minnow traps, I = incidental (observation, male vocalizations), and TN = number of trap nights.
Species A B C D E F G H I J K L M N P PP Q R S T U V W
Acris crepitans I I X I
Bufo americanus I I
Gastrophryne carolinensis
I
Hyla cinerea X X X X X X X X X I X X X X X X X
Pseudacris crucifer
Rana catesbeiana
X X I X X X X X X X X X X I X X X X X
Rana clamitans X X X X X X I X X X
Rana palustris I I I I I
Rana sphenocephala
X X X X X X X X X X X X X I X X X X X
Siren intermedia X X X X X X X X X X X X
Notophthalmus viridescens
Total No. of Species
2 4 5 3 4 4 5 2 8 5 5 5 2 4 8 4 4 10 4 4 2 3 3
Number of TN 230 185 110 80 60 240 100 140 50 170 230 140 60 160 290 15 100 228 80 150 20 90 60
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Chronology of Populations over Three Years
Variation in amphibian occurrence and relative abundance in the ponds studied on Coldwater National Wildlife Refuge is most clearly illustrated in a chronological order of events for each pond. The history of treatments by disk and herbicide, or lack thereof, is also included. These chronologies are included as tables in Appendix 2. Review of these chronologies reveals several conclusions:
1. Treatment histories for 12 of the 23 ponds revealed that some were treated multiple times with disk and herbicide and some received only one treatment, usually disking.
2. Larval amphibian populations were highly variable in occurrence and sample size among the 23 ponds, among species, and over time. Number of tadpole captures within a single species, such as Rana sphenocephala for example, varied from as few as 1 in pond F to as many as 267 in pond B per trap session.
3. Relative abundances of amphibians as measured by number per trap night in minnow traps were highly variable among ponds, species, and over time.
4. The high variation in numbers obtained during sampling sessions limited the number of direct comparisons of larval body size and relative abundance to two samples consisting of 6 ponds in each of two spring sampling sessions in two years.
5. Species occurrence and variation in relative numbers of snakes captured among ponds was also high. See Section 3.
Tadpole Size Variation Among Ponds
Comparison of species-specific tadpole samples caught in different ponds during the same trap session and year should provide insight into how these larvae respond to management treatments. Most sample sizes are either too small or were large enough but caught in different seasons and years to allow statistical comparison. However, two sets of samples can be examined for differences in the mass-length relationship among ponds. Sampling in April 2010 yielded statistical samples for Rana sphenocephala in a set of 6 ponds: B, E, K, L, T, and V. Sampling in March 2011 yielded statistical samples Rana sphenocephala in another set of 6 ponds: A, B, E, L, M, and R. Tables 1.2 and 1.3 and Figures 2.1 and 2.2 provide statistical and visual results, respectively.
Mean total length of Rana sphenocephala tadpoles in the April 2010 sample varied from 55.6 mm in pond K to 71.6 mm in pond L (Table 1.2). Mean body mass varied from 2.24 g in pond T to 3.74 g in pond L. Most of these tadpoles had small to large limb buds. There was
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considerable overlap in the range of values among all of these samples suggesting that there was a wide range of variation in growth among individuals or cohorts within each pond. The small sample size for pond K probably accounts for the smallest mean among these 6 ponds. The relationship of mass to total length (Figure 1.1) shows that no pond sample had a relationship that differed from any others. All samples were on the same slope and trajectory. This result supports the interpretation that the difference in body sizes among ponds is linear and can be attributed solely to variation in individual growth. The largest means for both total length and mass were for pond L. One conclusion might be that the tadpoles in Pond L were larger and more robust than those in ponds that had been treated because of the disk treatments in 2008 and 2011. It is possible, however, that lack of treatment in pond L in 2009 and 2010 resulted in a somewhat denser plant growth and a richer algal flora simply because there was more time for these communities to develop. These communities in treatment ponds were subjected to periodic removal and had less time to develop. The richer flora may have allowed some tadpoles in pond L to grow larger quicker. Thus, the effect of the treatments was probably not directly on the larval frog population but indirectly through the development of the plant communities. Alternatively, it may be that some Leopard Frogs laid eggs in pond L, perhaps in the previous fall, before those in other ponds and these tadpoles simply had more time to develop. All these ponds held water from reflooding from September to November the previous year and through the winter. If this hypothesis is valid, then some individuals chose to lay eggs in L early for unknown reasons.
Table 1.2. Statistical results for Rana sphenocephala samples caught in 6 ponds during the April 2010 trap session. Numbers are the mean, standard deviation, minimum – maximum, and sample size in parentheses.
Pond Total Length (mm) Mass (g)
B 68.20+6.8
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49-81 (37)
2.53+0.90
1.26-5.71 (37)
Figure 1.1. Relationship of mass with total length for Rana sphenocephala tadpoles from 6 ponds on Coldwater NWR for April 2010.
The results for the samples measured in March 2011 mirrored those for the samples measured in April 2010. Mean total length of Rana sphenocephala tadpoles in the March 2011 sample varied from 40.73 mm in pond M to 69.60 mm in pond L (Table 1.3). Mean body mass varied from 0.85 g in pond M to 2.86 g in pond L. All of the tadpoles in these 6 samples had small limb buds which correspond well with those in April 2010 which had slightly advanced stages of development. The difference is simply in the earlier sampling effort in March 2011. The considerable overlap in the range of values among all of these samples suggests that there was a
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wide range of variation in growth among individuals or cohorts within each pond. The relationship of mass to total length (Figure 1.2) clearly shows that no pond sample had a relationship that differed from all others. All samples were on the same slope and trajectory. This result supports the interpretation that the difference in body sizes among ponds can be attributed solely to variation in individual growth and perhaps to the timing of egg laying. Ponds A, L, and R received no treatments, whereas ponds B, E, and M received disk or herbicide treatment. Those from pond A averaged larger than those in ponds B and M but not those in pond E. Tadpoles in pond L averaged slightly larger than those in other ponds. And tadpoles from pond R were only larger than those in pond M. There is no consistent pattern between treated and untreated ponds. Thus, it appears that disk and herbicide treatments do not affect Leopard Frog body sizes and development.
Table 1.3. Statistical results for Rana sphenocephala samples caught in 6 ponds during the March 2011 trap session. Numbers are the mean, standard deviation, minimum – maximum, and sample size in parentheses.
Pond Total Length (mm) Mass (g)
A 62.20+4.94
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Figure 1.2. Relationship of mass with total length for Rana sphenocephala tadpoles from 6 ponds on Coldwater NWR for March 2011.
Conclusions
Total known species richness is highly variable among ponds with some supporting only two species compared to others that supported four or more. The variation is due to the hydrological cycles resulting from management practices that target waterfowl. The variation in how many species occupy each pond also varies among years and seasons. Ponds will dry from active management or from drought. All frog species will move from one pond to another as hydrologies change. Siren intermedia will aestivate in the substrate and wait for water to return. Central Newts may migrate as well but the capture of only one individual prevents any conclusions about its dynamics on the refuge. The number of species using a given pond will fluctuate over time but the presence of 23 ponds with differing hydrologies ensures that the amphibian populations on Coldwater NWR will remain dynamic but healthy.
Frog tadpole populations vary dramatically for the same reasons as adult populations. Production and recruitment of the larvae for some species will be high if the water in the breeding ponds remains long enough to allow tadpoles to complete development. Those species breeding in late winter to early spring (e.g., Leopard Frog, Spring Peeper) are more likely to be successful because water is present in at least several ponds and will persist until spring drawdown or summer heat and insolation dry them out. Species breeding in late spring or summer (e.g., Green Treefrog, Narrow-mouthed Toad) face greater risk of reproductive failure due to the higher
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variability in hydrologies. These species usually reproduce over longer periods of time during the year and have shorter larval periods that allow them to be successful in at least some ponds each year.
Comparisons of two sets of Leopard Frog larvae from several ponds in the same season reveal no detectable effects of herbicide or mechanical treatments on body size or condition. Tadpoles in some ponds grow to larger sizes than in others perhaps due to pond primary productivity. The variation in size within single populations in ponds with different management histories suggest that tadpole growth may be tied to the abundance of algae and other sources of food. Ponds that have no management for several years likely have more developed floral communities and thus higher productivity. These ponds produce large tadpoles. However, the presence of small tadpoles in the same ponds suggests that growth and response to the higher productivity may be individualistic. An equally valid hypothesis is that some adults lay eggs earlier than others and the larger tadpoles have had more time to grow. These differences underscore the subtle responses to environmental conditions. The important conclusion is that frog tadpole populations are not adversely or directly affected by management treatments. The most important environmental variable affecting amphibians in the ponds is hydrology. The amphibians respond to those varying conditions by migrating to ponds that have water. The variable responses to changing water levels by reproductive adult amphibians create the complex interplay of management treatments (mostly drawdown schedules) with water levels, natural water loss from evaporation, frog responses to water dynamics, species larval developmental periods, and food availability from pond flora. The large number of ponds with their varying environments is key to the success of amphibians on the refuge. Fewer ponds would limit opportunities for reproductive success and could be a factor in local extirpation of some species. There are simply more opportunities for reproduction in the larger complex of ponds.
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Section 2. Lesser Siren (Siren intermedia) in Coldwater National Wildlife Refuge
Introduction
Siren intermedia occur in a wide variety of aquatic habitats ranging from farm ponds to ditches and swamps where there is an abundance of aquatic vegetation (Pretranka, 1998; Leja, 2005). Survival in ephemeral ponds and those that dry on an irregular schedule is accomplished by aestivation in the muddy substrate. Siren secrete a cocoon of mucous that hardens during prolonged dry periods (Reno et al., 1972). Return of rainwater causes them to emerge from these cocoons. Survival of Siren intermedia in wildlife ponds that are disked during willow control management depends on disk depth. Large disks likely caused greater mortality than smaller disks. Mortality rates in the wildlife ponds in Coldwater National Wildlife Refuge are unknown because Siren intermedia was unknown for this refuge until this study began. Thus, the capture numbers reported in here represent those that survived previous disking histories and recruitment through reproduction.
This report summarizes the variation in captures among wildlife ponds and body size relationships for Siren intermedia in Coldwater National Wildlife Refuge.
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Materials and Methods
All sirens were captured with GEE minnow traps as described in Section 1. Standard measurement for all individuals was snout-vent length (SVL) and total length. Most were also weighed to the nearest 0.1 gram with an electronic balance or Pesola scales. Size at maturity was based on published minimum adult size for Siren intermedia in South Carolina (115 mm SVL, Sever et al., 1996), Illinois (92 mm SVL, McDowell, 1997), and small body masses of the Coldwater NWR sample.
Results
Occurrence and Capture Results
Siren intermedia were captured in 14 of the 23 ponds trapped in this study (Table 2.1). Ponds B, F, G, H, I, J, K, M, P, PP, Q, R, S, and V yielded at least one capture of this species. In these ponds, number per trap night varied from 0.006 to 0.133 (Table 2.1). The pond yielding the most total captures was P with a sample of 37, 31 of which were captured during one trapping session on 8-9 September 2009 in 10 minnow traps. Number per trap in this session ranged from one to 8, with a mode of 4. Five ponds (B, F, G, H, AND M) yielded only one Siren intermedia despite the extensive trapping. Ponds that had the highest number of captures were consistently those with thick aquatic vegetation and/or clumps of buttonbush. The latter have dense root systems above the substrate that allowed for shelter of all sizes classes of Siren.
Numbers captured among sessions and ponds varied dramatically over the study period (Table 2.2). This may be due in part to seasonal activity tied to water temperatures. Frese (2000) showed that capture rates of Siren in Missouri were highest in colder months with water temperatures between 2 and 8 C. Variation in capture success in this study may have been influenced by the warm weather in which most of the trapping took place. Number of captures in March-April (1-4), June (1-7), and September (1-31) suggest, however, that water temperature is not the only environmental variable influencing activity rates and capture success. A year-round monthly trapping program would shed light on activity rates in Coldwater NWR ponds.
Table 2.1. Summary of numbers of Siren intermedia caught in each pond during 2009-2011.
Pond No. of Trap Nights No. of Siren No. per Trap Night
A 190 0 --
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Table 2.2. Ponds in which Siren intermedia were captured on Coldwater National Wildlife Refuge. Cells include dates, number of individuals (expressed as number per trap night) per trap session, and total number caught (in parentheses). The number in brackets is the number of trap nights in the session.
Pond date
8-10 Jun 09 0.117/tn (7) [60]
10-14 Apr 10 0.017/tn (1) [60]
21-23 Mar 10 0.1/tn (4) [40]
K 6-9 Jun 09 0.017/tn (1) [60]
12-14 Apr 10 0.025/tn (1) [40]
1-4 Sep 10 0.117/tn (14) [120]
M 22-25 Mar 11 0.017/tn (1) [60]
P 7-9 Sep 09 0.52/tn (31) [60]
10-12 Apr 10 0.025/tn (1) [40]
17-18 Jun 10 0.1/tn (2) [20]
21-24 Mar 11 0.033/tn (1) [30]
11-13 Jun 11 0.025/tn (1) [40]
23-25 Sep 11 0.025/tn (1) [40]
PP 8-9 Sep 09 0.067/tn (1) [15]
Q 17-19 Jun 10 0.017/tn (1) [60]
R 21-24 Mar 11 0.1/tn (3) [30]
9-11 Jun 11 0.03/tn (1) [30]
23-25 Sep 11 0.075/tn (3) [40]
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4-5 Sep 10 0.5/tn (5) [10]
Body Size Relationships
Siren intermedia body size ranged from 92 mm to 285 mm SVL (mean = 170.8+52.0, n = 29), 130 mm to 397 mm total length (mean = 267.2+68.3, n = 75), and 5.2 g to 128 g body mass (mean = 39.4+25.9, n = 73). The smallest individual was 92 mm SV, 130 mm total length, and 5.2 g body mass. The largest was 285 mm SVL, 397 mm total length, and 128 g. The four juveniles were 92, 98, 99, and 100 mm SVL; 130, 137 (2), and 138 mm total length, and 5.2, 5.4, 6.2, and 6.9 g body mass, respectively. Snout-vent length of adults ranged from 104 mm to 285 mm (mean = 179+48.1, n = 35), 153 mm to 368 mm total length (mean = 274+62.3, n = 71), and 10 g to 128 g body mass (mean = 41.7+25.3, n = 70).
The relationship of tail length to total length is linear without substantial variation along the slope (Figure 2.1). Unfortunately, tail length cannot be used to determine the gender of an individual; there are no obvious groupings that would allow discrimination between the sexes. The relationship of mass to body size was logarithmic (Figure 2.2).
Figure 2.1. Relationship of tail length to total length in Siren intermedia in Coldwater NWR.
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Figure 2.2. Relationship of body mass to total length in Siren intermedia in Coldwater NWR.
Conclusions
Siren intermedia inhabit at least 14 ponds on Coldwater NWR. Their presumed absence in the other ponds may be due to true absence or lack of capture success. Colonization or recolonization of ponds may occur on occasion because this species has been documented to move several hundred meters away from aquatic habitats during wet weather (Leja, 2005). Thus, sirens could potentially occur in all the ponds on the refuge over time.
Sirens respond to pond drying by retreating into crayfish burrows to a depth of as much as 1 meter or burrowing into the substrate to a depth of 8-10 cm (Leja, 2005). Disking of dry ponds could kill salamanders if the blade depth reaches 8 cm or more. Does low capture success in some ponds and complete absence in others reflect historical mortality rates due to disking with large blades? This question cannot be answered due to the lack of previous information on these salamanders. Thus, the most appropriate management option to prevent mortality would be to ensure that blade radius be less than 8 cm.
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Nerodia cyclopion (Mississippi Green Watersnake)
Introduction
The system of freshwater ponds in Coldwater NWR that attracts frogs and Siren also attracts their snake predators. Some of these ponds support several species of fish and in some cases an abundance of crayfish. The result is that the snake fauna on this refuge consists of mostly frog and fish specialists, one that feeds exclusively on Siren, and one that specializes on crayfish. Although the goal of this study was to assess amphibian populations, the trapping method used also allows for an assessment of the snake populations. This section includes an evaluation of the snake fauna on Coldwater NWR.
Materials and Methods
The primary method used to obtain quantitative data on snake populations in the wildlife ponds on Coldwater National Wildlife Refuge was standard minnow traps (GEE minnow traps, Memphis Net and Twine Co.). During each field session, a set of 10-20 traps was set in shallow water (when present or deep enough) with enough room for snakes to reach air in each study pond. The funnel opening of each trap was enlarged to about 3 mm in diameter that allowed capture of adults and juveniles. Where possible, I set 20 traps per pond. In some sessions water levels were too low to accommodate 20 traps; 10 traps were used in most of these instances. Traps were operational for a total of 40 trap nights per pond but in some trips the number of trap
22
nights was limited to 20. These sessions usually occurred when large numbers of captures occurred with this sample size that allowed comparisons without having to trap for longer periods. I counted the number individuals of each species caught in each trap during each session. Numbers reported in this study are number per trap night.
Each snake captured was measured (SVL and total length, nearest mm) and weighed with Pesola scales to the nearest gram. Gender was determined by examining the base of the tail – a tail base equal to the width of the cloacal region are males, and tails that distinctly taper distally from the cloacal region are females.
Results
Diversity among ponds
The snake fauna in the ponds on Coldwater NWR consists of 5 species in two genera (Agkistrodon and Nerodia) that feed on frogs and fish, the Siren specialist Farancia abacura, and the crayfish specialist Regina grahamii (Table 3.1). Snakes were trapped in all but two of the ponds studied: PP and W. Number of species per pond varied from 1 in ponds A, C, G, H, L, V, and X to 5 in pond R. Of the frog and fish predators, N. rhombifer occurred in the highest number of ponds (20), followed by N. fasciata (14), N. erythrogaster (7), and N. cyclopion (1). Farancia abacura occurred in 7 ponds and Agkistrodon piscivorus and Regina grahamii occurred in 3 each. Number of captures per trap night for each species varied dramatically among and within ponds (Table 3.2). Per night capture rates varied from 0.004 in pond R to 0.200 in pond T. Of the five most commonly captured snakes, 3 species (A. piscivorus, N. erythrogaster, and N. cyclopion) shared the lowest capture rates (0.004) in pond R. The highest per night capture rate (0.200) was for Nerodia rhombifer in pond T.
Two snake species encountered on Coldwater NWR but not caught in minnow traps were the Western Ribbon Snake (Thamnophis proximus) and the Central Ratsnake (Pantherophis spiloides). The Ribbon Snake was observed but not captured in shrubs adjacent to pond R on 4 September 2011. The juvenile female Ratsnake (457 mm SVL, 559 mm total length, 24 g) was found alive on the public access road adjacent to pond J on 11 June 2009. Thus, the total known snake fauna on Coldwater NWR consists of 9 species (Appendix 1).
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Table 3.1. Snake species occurrence in 23 ponds on Coldwater NWR.
Species A B C D E F G H I J K L M N P Q R S T U V X
Agkistrodon piscivorus
Nerodia cyclopion
Nerodia fasciata
X X X X X X X X X X X X X X
Nerodia rhombifer
X X X X X X X X X X X X X X X X X X X X
Regina grahamii
X X X
Total per pond 1 4 1 2 4 3 1 1 3 4 4 2 1 2 4 4 5 2 4 2 1 1
No. of trap nights
190 165 110 80 60 280 100 140 50 170 230 140 60 160 290 100 228 80 150 20 70 15
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Table 3.2. Total number of the five most commonly caught snake species in Coldwater NWR ponds and number per trap night in parentheses in nine trapping sessions from 2009 to 2011.
Pond
C 110 2 (0.018)
E 60 24 (0.040) 4 (0.067) 1 (0.017)
F 280 5 (0.018) 3 (0.011)
G 100 2 (0.020) 1 (0.010)
H 140 2 (0.014)
K 230 15 (0.065) 3 (0.013)
L 140 6 (0.042) 7 (0.050)
M 60 2 (0.033)
P 290 15 (0.052) 6 (0.021) 2 (0.007) 2 (0.007)
Q 100 5 (0.050) 6 (0.060) 1 (0.010) 1 (0.010)
R 228 8 (0.035) 2 (0.009) 1 (0.004) 1 (0.004) 1 (0.004)
S 80 1 (0.013) 2 (0.025)
T 150 30 (0.200) 3 (0.020) 1 (0.007)
25
V 70 6 (0.086)
Body Size Patterns
Body sizes varied among species and between sexes and age groups (Table 3.2). The largest snake captured was a female Farancia abacura with a total length of 1500 mm total length. Adult females averaged larger and attained longer total lengths than males for all species. Such comparisons for N. cyclopion and R. grahamii were not possible because only one sex of each was captured.
As expected, body mass was logarithmically-related to total length for three species (Figures 3.2 -3.4). The only exception was the linear relationship for F. abacura (Figure 3.1). This result was most likely due to the small sample size.
Table 3.3. Body measurements for adult males, adult females, and juveniles for seven species of snakes on Coldwater National Wildlife Refuge. Number is the mean + standard deviation with minimum-maximum and sample size in parentheses.
Species Snout-vent Length (mm)
Juvenile Females 426.0+133.7
27
Figure 3.1. Relationship of body mass with total length in Farancia abacura on Coldwater NWR.
Figure 3.2. Relationship of body mass with total length in Nerodia erythrogaster on Coldwater NWR.
28
Figure 3.3. Relationship of body mass with total length in Nerodia fasciata on Coldwater NWR.
Figure 3.4. Relationship of body mass with total length in Nerodia rhombifer on Coldwater NWR.
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Conclusions
The snake fauna on Coldwater NWR is dominated by watersnakes. The Diamond-backed Watersnake (Nerodia rhombifer) was the most commonly captured snake and occurred throughout the refuge. Three species (N. erythrogaster, N. fasciata, N. rhombifer in increasing relative abundance) were the most likely-encountered snakes in each pond. Mud Snakes (Farancia abacura), Graham’s Crayfish Snake (Regina grahamii), and the Mississippi Watersnake (Nerodia cyclopion) were the species least likely to be encountered. The Western Cottonmouth (Agkistrodon piscivorus) is also uncommonly encountered but the fact that this snake is venomous and potentially lethal means that persons working on the refuge should take all precautions when walking along banks and in shallow water.
Body sizes, sexual dimorphism patterns, and relationships of mass to length are consistent with the known biology of these species (Ernst and Ernst, 2003).
The snake fauna now known to consist of 9 species is likely to increase with additional observations because some snakes are exceptionally secretive and seldom encountered. Results from this study suggest that management treatments have no affect on snake populations on Coldwater NWR.
Farancia abacura in defensive posture.
30
Kinosternon subrubrum mississipiensis (Mississippi Mud Turtle)
Introduction
Despite the fact that wildlife ponds fluctuate hydrologically and often become dry, these ponds are used by several species of freshwater turtles. All of these species are well known to move overland and some spend long periods in terrestrial aestivation (Ernst and Lovich, 2009). Trapping for turtles was accessory to the primary effort on amphibians (see Section 1). In this report I describe the known freshwater turtle fauna on Coldwater NWR and the body size characteristics of each species.
Materials and Methods
I trapped several wildlife ponds with standard turtle hoop nets (30 inch and 20 inch diameter traps, Memphis Net and Twine) during several field sessions to obtain information on species richness among sample ponds and information on body size. Because trapping for turtles was accessory to the primary effort on amphibians, the effort was inconsistent among sample periods and limited to those ponds with water deep enough to allow the trap throat to be set below the surface. Each trap was baited with a can of sardines which were opened partially to allow the bait odor to disperse.
Each turtle captured was measured (nearest mm) for straight-line maximum carapace length, straight-line maximum plastron length, and mass (nearest 0.1 g for small turtles, nearest g for all but the largest turtles, and nearest 10 g for very large turtles, e.g., Chelydra serpentina). Gender was determined by examination of secondary sex characteristics, usually by inspection of the
31
elongated tail base in which the position of the cloacal opening extended beyond the posterior margin of the carapace or not. If it did so, it was scored as a male. Cloacal openings of females do not reach the edge of the carapace. Each individual was marked with drill holes or V-shaped notches filed in coded marginal scutes following Mitchell (1988) using a 1,2,4,7 system with ones on the anterior left (not including the nuchal), tens on the anterior right, 100s on the posterior left, and 1000s on the posterior right (Figure 4.1). This code was modified for Snapping Turtles with the posterior left marginals coded 1, 2, 4, 7 from the midline and the tens on the posterior right coded 10, 20, 40, and 70 from the midline.
Figure 4.1. Numbering scheme for marking freshwater turtles.
Results
Diversity Among Ponds
A total of six species of freshwater turtles were encountered on Coldwater NWR (Table 4.1). They were found to occupy 9 of the 23 ponds studied. The most commonly captured species was the Red-eared Slider (Trachemys scripta) which occurred in all 9 ponds. It was also the most abundant with 92 captures. Shells of sliders were found occasionally along the banks of several ponds in addition to the ones in the Table 4.1 but they were not systematically recorded. Only one individual of the Southern Painted Turtle (Chrysemys dorsalis) was captured (pond R). Pond R supported 5 species when it held water, whereas only one species was recorded for ponds F, H, Q, and U.
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Table 4.1. Freshwater turtle species richness in 10 wildlife ponds, on the Levee Road and in the creek to the southeast of the ponds on Coldwater National Wildlife Refuge. Number represents the total number of individuals captured in each pond. Species code as in Appendix 1.
Pond APASPI CHESER CHRDOR KINSUB STEODO TRASCR Total Species
A 1 1 2
Q 1 1
U 1 1
Levee Rd 1
Body Size and Sexual Dimorphism
The largest turtle captured was a Common Snapping Turtle (Chelydra serpentina) that measured 327 mm carapace length and weighed 7.95 kilograms (Table 4.2). The largest Trachemys scripta was a female measuring 237 mm carapace length and weighing 2.76 kilograms. The species with the smallest adults was the Common Musk Turtle (Sternotherus odoratus) that measured 62 mm carapace length.
Sample sizes for three species were large enough to evaluate sexual size dimorphism (Table 4.2). Chelydra serpentina males averaged larger (313 mm carapace length) than females (302 mm). Although the sample size is small, the difference is consistent with the known biology of this species (Ernst and Lovich, 2009). Average carapace lengths for male and female Kinosternon
33
subrubrum were nearly identical (91.6 mm and 91.7 mm, respectively). Sexual size dimorphism is strongest for Trachemys scripta. Female carapace length averaged substantially larger (206.1 mm) than carapace lengths for males (169.1 mm). A similar relationship holds for plastron length and body mass (Table 4.2). These relationships are consistent with the patterns summarized in Ernst and Lovich (2009) for these species.
The sample size for Trachemys scripta was large enough to examine the relationship of body mass to body size (plastron length). The relationship is logarithmic (Figure 4.2) as expected. The three outliers on the right side of the trajectory were females that were substantially larger than most females in this population.
Table 4.2. Adult body sizes (carapace, plastron, mass) for males, females, and juveniles for six species of turtles on Coldwater National Wildlife Refuge. Number is the mean + standard deviation with minimum-maximum and sample size in parentheses.
Species Maximum Carapace Length (mm)
Maximum Plastron Length (mm)
Juveniles 222 (1) 153 1890
Chrysemys dorsalis Male
34
Sternotherus odoratus
Adult Males
81.6+17.0
62.2-101.2 (4)
64.4+12.8
47.1-77.3 (4)
99.4+59.6
37.6-175 (4)
Trachemys scripta
Adult Males
169.1+24.7
111.2-215 (35)
154.0+21.5
101.1-196 (35)
652.1+24.6
204-1280 (35)
996
96.2-103
125
67-183
Figure 4.2. Relationship of body mass with plastron length for Trachemys scripta on Coldwater NWR.
35
Conclusions
A total of six species of freshwater turtles were encountered on Coldwater NWR during the 2009-2011 study. The largest turtle captured was a Common Snapping Turtle (Chelydra serpentina) that measured 327 mm carapace length and weighed 7.95 kilograms. Adult Common Musk Turtles (Sternotherus odoratus) are as small as 62 mm carapace length. The most abundant species is the Red-eared Slider (Trachemys scripta) and was found in all the ponds trapped. They were also seen in several other ponds that were not trapped, suggesting that this species may occur anywhere in the pond complex. Sexual size dimorphism results were consistent with published accounts. No hatchling turtles were found suggesting that most of the turtles in refuge ponds were migrating adults.
The turtle fauna on Coldwater NWR is thus a transient one because each species migrates to the ponds from local source populations. However, if all of the ponds dry either seasonally or in drought years, then turtles move from these ponds to other bodies of water. Some turtles likely move overland to nearby ponds or move along the creeks until they reach more permanent water. The number of species occurring in refuge ponds will vary annually and seasonally depending which ponds have water and the migration rates of individuals. Management actions such as disking and application of herbicides for willow control should have little to no effect on these animals.
One management action, grass mowing, may harm individual turtles by being crushed by the mower or cut by the blades. It would be valuable to know how high the mower platform is set to determine if it would likely harm turtles sitting in grass. Blade height can be adjusted to avoid killing terrestrial turtles.
Red-eared Slider (Trachemys scripta elegans)
36
Section 5. Management of Amphibians and Reptiles in Coldwater National Wildlife Refuge
The results of the studies conducted on Coldwater NWR during 2009-2011 provides information that could influence management practices on the refuge.
Average number of amphibian species in treatment ponds (4.27) was nearly identical to the average number in notreatment ponds (4.33). Additionally, relative abundance of amphibians in treated ponds (0.815) was only slightly higher than that in notreatment ponds (0.551). Frog populations apparently have not been adversely or directly affected by management treatments of disking or herbicide applications. Analysis of body size relationships in Leopard Frog samples obtained during the same sampling period showed that disk and herbicide treatments do not directly affect body sizes and development of this species.
Siren intermedia aestivate in the pond substrate to depths of 8 cm or more. Mechanical disking that reaches that level may be a source of mortality. An appropriate management option to prevent mortality from this source would be to ensure that blade radius be less than 8 cm.
The snake known fauna consists of 9 species and all ponds are occupied by at least two or three species. The Western Cottonmouth is uncommonly encountered on the refuge but the fact that this snake is venomous and potentially lethal means that persons working on the refuge should take all precautions when walking along banks and in shallow water.
Although most turtles on the refuge are aquatic, all of them spend time on land on the banks and in grasses around the ponds. One management action, grass mowing, may harm individual turtles by crushing them by the mower or cut by the blades. A practical management option is to adjust mower blade height upward to avoid killing terrestrial turtles.
Overall, little change in management effort is needed to ensure that robust populations of amphibians and reptiles continue to exist on Coldwater NWR. With a few small exceptions, current management activities apparently have little negative impact on these animals. The use of mechanical and chemical treatments to control invasive willow growth appears to have little to no effect on amphibian populations on the refuge.
37
Literature Cited
Blaustein, A.R., and L.K. Belden. 2005. Ultraviolet radiation. Pp.87-88, In M. Lannoo (editor), Amphibian Declines, The Conservation Status of United States Species. University of California Press, Berkeley, CA.
Bridges, C.M., and R.D. Semlitsch. 2005. Variation in pesticide tolerance. Pp.93-95, In M. Lannoo (editor), Amphibian Declines, The Conservation Status of United States Species. University of California Press, Berkeley, CA.
Ernst, C.H., and E.M. Ernst. 2003. Snakes of the United States and Canada. Johns Hopkins University Press, Baltimore, MD.
Ernst, C.H., and J.E. Lovich. 2009. Turtles of the United States and Canada. Johns Hopkins University Press, Baltimore, MD.
Frese, P.W. 2000. Spatial activity, growth, and population characteristics of Siren intermedia in an intensively managed wetland. MS thesis, Southwest Missouri State University, Springfield, MO. 55 pp.
Leja, W.T. 2005. Siren intermedia Barnes, 1826. Pp.910-912, In M. Lannoo (editor), Amphibian Declines, The Conservation Status of United States Species. University of California Press, Berkeley, CA.
McDowell, W.T. 1997. Life history notes on Siren intermedia in southern Illinois. Bulletin of the Chicago Herpetological Society 32:226-228.
Mitchell, J.C. 1988. Population ecology and life histories of the freshwater turtles Chrysemys picta and Sternotherus odoratus in an urban lake. Herpetological Monographs 2:40-61.
Petranka, J.W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington, DC.
Reno, H.W., F.R. Gehlbach, and R.A. Turner. 1972. Skin and aestivational cocoon of the aquatic amphibian, Siren intermedia. Copeia 1972:625-631.
Rothermel, B.B., S.C. Walls, J.C. Mitchell, C.K. Dodd, Jr., L. Irwin, D.E. Green, V. Vazquez, J.W. Petranka, and D.J. Stevenson. 2008. Widespread occurrence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) in the Southeastern United States. Journal of Aquatic Diseases 82:3-18.
Sever, D.M., L.C. Rania, and J.D. Krenz. 1996. Reproduction in the salamander Siren intermedia Le Conte with especial reference to oviductal anatomy and mode of fertilization. Journal of Morphology 227:335-348.
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Appendix 1 – Checklist of the known amphibians and reptiles of Coldwater National Wildlife Refuge.
Scientific Name Common Name Species Code
Amphibians
Bufo americanus americanus
American Toad BUFAME
Gastrophryne carolinensis Eastern Narrow-mouthed Toad
GASCAR
Pseudacris crucifer crucifer Northern Spring Peeper PSECRU
Rana catesbeiana American Bullfrog RANCAT
Rana clamitans clamitans Bronze Frog RANCLA
Rana palustris Pickerel Frog RANPAL
Rana sphenocephala Southern Leopard Frog RANSPH
Siren intermedia nettingi Western Lesser Siren SIRINT
Notophthalmus viridescens louisiananensis
Central Newt NOTVIR
Farancia abacura reinwardtii Western Mud Snake FARABA
Nerodia cyclopion Mississippi Green Watersnake NERCLY
39
Regina grahamii Graham’s Crayfish Snake REGGRA
Thamnophis proximus proximus
(may intergrade with Gulf Coast Spiny Softshell)
APASPI
Kinosternon subrubrum mississippiensis
40
Appendix 2 – Chronology of management actions and field results for 23 wildlife ponds on Coldwater National Wildlife Refuge. Pond X was not included in the study.
Pond A. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Held water fairly well through spring and into summer. Shorebird drawdown delayed slightly due to beaver dams in drainage ditch. Began drawdown 8/15.
2009 FWS- Water held in unit until end of July when slowly drawndown for shorebirds. Rains in early September negated any draw down. Unit reflooded by mid-October.
25-27 March 2009 10 MT/20 tn 0 amphibians
June 2009 Too shallow, 0 traps
September 2009 Too shallow, 0 traps
2010 FWS-Not able to draw down--level of water in ditch stayed high and unit water level fluctuated from high of over 3.5 feet in March to 0.74 feet in October. Mostly mud flat in Oct.
11-13 April 2010 20 MT/20 tn 6 RANSPH tad 0.3/tn
16-17 June 2010 20 MT/20 tn 0 amphibians, 2 NERRHO 0.1/tn
1-3 September 2010 5 MT/10 tn 0 amphibians
2011 FWS- Water held, summer drawdown but retained water due to backflow from ditch
21-24 March 2011 20 MT/60 tn 59 RANSPH tad 0.98/tn
9-12 June 2011 20 MT/40 tn 1 RANCLA tad 0.025/tn, 4 NERRHO/0.1/tn
22-24 September 2011 20 MT/40 tn 1 RANCAT juv 0.025/tn
41
Pond B. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 3/10. Some backflowing from ditch. Unit nearly dry by 4/24, completely dry by 5/29. Disked 7/8 - 10. Reflooded 7/28 -30.
2009 FES-Drawdown begun 3/6. Mud flat by 4/20 but to full pool by 5/7 (backflowed from ditch). Unit dry by 6/5. Periodic rain in summer, but no major water accumulation until 9/21, when it rained, ditch backflowed into unit.
25-27 March 2009 10 MT/20 tn 0 amphibians
June 2009 Too shallow, 0 traps
September 2009 Too shallow, 0 traps
2010 FWS-Began drawdown May 12. Unit sprayed July 15th. Unit reflooded beginning Oct. 6.
9-12 April 2010 20 MT/40 tn 267 RANSPH tads 6.7/tn, 1 SIRINT 0.025/tn, 6 NERRHO 0.15/tn, 1 NERERY 0.025/tn, 1 NERFAS 0.025/tn
16-17 June 2010 20 MT/20 tn 10 RANSPH tads 0.5/tn, 6 NERRHO 0.15/tn
1 September 2010 dry
2011 FWS- Early drawdown (early March), mowed, reflooded in August
21-24 March 2011 20 MT/60 tn 16 RANSPH tads 0.27/tn, 1 RANSPH ad 0.017/tn, 1 NERRHO 0.017/tn
9-10 June 2011 5 MT/5 tn 21 HYLCIN tad 4.2/tn
22-24 September 2011 20 MT/40 tn 1 HYLCIN tad 0.025/tn, 1 RANCAT juv 0.025/tn, 1 RANCAT tad 0.025/tn, 4 NERRHO 0.1/tn, 1 REGGRA 0.025/tn
42
Pond C. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 3/10. Unit backfilled in early April then dried except for large pool by 4/24. Entire unit dry by mid- June.Reflooded 10/8 - 10.
2009 FWS-Drawdown begun 6/5 (delayed due to rains in May). By 8/6 only pool remained (never dried fully). Treated with 1 pt/acre of ultrablazer 8/31.
26-27 March 2009 10 MT/10 tn 141 RANSPH tads 14.7/tn
6-10 June 2009 20 MT/60 tn 2 HYLCIN tads 0.03/tn, 2 RANCLA tads 0.025/tn, 2 NERRHO 0.025/tn
1 September 2009 Too shallow, 0 traps
2010 FWS-Began drawdown March 3. Unit dry by June 1. Disked June 28, reflooded July 12 - 14. Began shorebird drawdown August 2. Unit dried somewhat by 9/12. Reflooded 9/14-15.More water added beginning 10/28 to replenish.
9-10 April 2010 20 MT/40 tn 4 RANSPH tads 0.1/tn
17 June 2010 Too shallow, 0 traps
1 September 2010 dry
2011 FWS- Early drawdown, partial mow, reflooded after all sampling complete
21 March 2011 Too shallow, 0 traps
9 June 2011 dry, too shallow
22 September 2011 dry
43
Pond D. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 5/20. Majority of unit dry by 7/7. Unit sprayed 8/8 with UltraBlazer (17 pts.) Used 20 gallons of water/acre. Unit reflooded by rainwater.
2009 FWS- Drawdown begun 3/6. Dry at wcs by 4/20 (pool remained) but back up to nearly full pool by 5/22 (backflowed from ditch). Unit dry at wcs (pool remaining) by 6/5. Periodic rain throughout summer, but disking finally accomplished by 8/27. Began reflooding 9/18, at full pool by 9/21.
26-27 March 2009 Too shallow, 0 traps
6 June 2009 Too shallow, 0 traps
1 September 2009 Too shallow, 0 traps
2010 FWS-Began drawdown 5/12. Unit dry by 7/1. Sprayed 7/15. Unit reflooded 9/14.
9-11 April 2010 10 MT/20 tn 3 RANSPH tads 0.15/tn
17 June 2010 Too shallow, 0 traps
1 September 2010 dry
2011 FWS- Drawdown start end March, disked, reflooded, mid-August, pulled down again beginning of Sept.
22-24 March 2011 20 MT/40 tn 4 RANSPH tads 0.1/tn, 2 RANSPH ad 0.05/tn, 1 NERRHO 0.025/tn
9 June 2011 dry
22-24 September 2011 10 MT/20 tn 13 HYLCIN tads 0.65/tn, 1 RANCAT juv 0.2/tn, 1 RANCAT tad 0.025/tn, 1 NERERY 0.025/tn
44
Pond E. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 3/10. Backfilling 4/7, but unit mostly dry by 5/1. Disked 7/10 - 14. Reflooded 7/28 - 8/4.
2009 FWS-Drawdown begun 3/6. Dry at wcs by 4/8, still has small pool in middle. Backflowed in May to about 1/2 pool. Completely dry by 6/24. Refilled by rainwater by 11/1.
26 March 2009 dry
6 June 2009 dry
1 September 2009 dry
2010 FWS-Began drawdown 5/12. Unit dry by 7/1. Sprayed 7/15. Unit reflooded 9/14.
13-14 April 2010 20 MT/20 tn 52 RANSPH tads 2.6/tn, 6 NERRHO 0.3/tn, 1 NERERY 0.05/tn, 1 NERFAS 0.05/tn
16-17 June 2010 20 MT/20 tn 1 BUFFOW juv 0.1/tn, 6 RANSPH tads 0.3/tn, 1 RANSPH juv 0.05/tn, 16 NERRHO 0.8/tn, 2 NERFAS 0.1/tn
1 September 2010 dry
2011 FWS- No mgmt
21-22 March 2011 20 MT/20 tn 16 RANSPH tads 0.8/tn, 1 RANSPH ad 0.05/tn, 1 RANCAT juv 0.05/tn, 2 NERRHO 0.1/tn, 1 NERFAS 0.05/tn
9 June 2011 dry
22 September 2011 dry
45
Pond F. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown prior to 3/1 Backfilled 4/7 - 4/10 then equalized with ditch. Large pools present through 6/20 at least. Unit reflooded 10/8 - 10.
2009 FWS- Drawdown begun 3/6. Nearly dry by 4/20 but backflowed in May so nearly full pool by 5/22. Dry at wcs by 7/16, with a few pools remaining. Disked around 8/27. Reflooded beginning 9/18. At full pool by 9/21
26 March 2009 Too shallow, 0 traps
6-10 June 09 20 MT/60 tn 1 HYLCIN tad 0.012/tn, 1 RANSPH tad 0.012/tn, 1 NERRHO 0.012/tn. 1 REGGRA 0.012/tn
6 September 2009 dry
2010 FWS- drawdown March 1, dry NLT May 1, disk
12-14 April 2010 20 MT/40 tn 1 SIRINT 0.025/tn, 1 NERRHO 0.025/tn
17-19 June 2010 20 MT/40 tn 1 HYLCIN tad 0.025/tn, 1 BUFFOW ad 0.025/tn, 1 NERRHO 0.025/tn, 1 NERFAS 0.025/tn
1-3 September 2010 20 MT/40 tn 1 HYLCIN tad 0.025/tn, 1 RANSPH ad 0.025/tn, 1 NERFAS 0.025/tn
2011 FWS- Early drawdown, mowed, reflooded in August
23-24 March 2011 20 MT/20 tn 1 RANSPH tad 0.05/tn
9 June 2011 dry
22-24 September 2011 20 MT/40 tn 1 RANCAT juv 0.025/tn, 1 RANSPH ad 0.025/tn, 2 NERRHO 0.05/tn, 1 NERFAS 0.025/tn
46
Pond G. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 5/20. Dry by 6/30. Disked 7/23 - 25 Reflooded 8/11 - 13.
2009 FWS-Water held in unit throughout year (promote submerged aquatics).
26 March 2009 Dry
6 June 2009 Dry
6 September 2009 Dry
13-14 April 2010 20 MT/20 tn 1 RANCAT juv 0.05/tn
17 June 2010 Too shallow, 0 traps
1 September 2010 dry
2011 FWS - Drawdown start end March, disked, reflooded, mid-August, pulled down again beginning of Sept.
21-23 March 2011 20 MT/40 tn 6 RANSPH tads 0.15/tn, 1 RANCAT juv 0.025/tn, 2NERFAS 0.05/tn
9 June 2011 dry
22-24 September 2011 20 MT/40 tn 15 HYLCIN tads 0.375/tn, 2 RANSPH tads 0.05, 1 SIRINT 0.025/tn, 1 NERERY 0.025/tn
47
Pond H. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS- Began drawdown 5/20. Mostly dry by 6/30, though pool remained in center. Unit sprayed 8/13. Applied 17 pts of Ultrablazer over unit using 10 gallons of water per acre.
2009 FWS- Drawdown begun 6/5 (delayed due to rains in May). By 8/6 only pool remained (never dried fully). Treated with 1 pt/acre of ultrablazer 8/31.
26 March 2009 Too shallow, 0 traps
6-9 June 2009 20 MT/60 tn 0 amphibians
6 September 2009 Too shallow, 0 traps
2010 FWS-Drawdown began 3/16. Unit dry by 7/1 (maybe prior?). Disked 7/7, reflooded 7/22. Reflooded 10/6, water periodically added during winter.
13-14 April 2010 20 MT/20 tn 1 RANCAT juv 0.05/tn, 2 NERRHO 0.1/tn
17 June 2010 Too shallow, 0 traps
1-4 September 2010 20 MT/40 tn 1 RANSPH ad 0.025/tn, 1 SIRINT 0.025/tn
2011 FWS - Early drawdown, mowed, reflooded late Oct.
21-24 March 2011 20 MT/20 tn 0 amphibians
9 June 2011 Water depth too shallow
22 September 2011 dry
48
Pond I. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Water held well throughout spring and into summer. Began drawdown 8/6. Never pulled all boards - unit equalized with ditch, then dried in front of structure, leaving a pool in middle of unit that never dried.
2009 FWS-Water held until 8/20 when began shorebird drawdown. Had already dried somewhat from evaporation. Never dried entirely--rains in September quickly refilled unit. Unit back filled from ditch and at full pool by November.
26-27 March 2009 10 MT/10 tn 1 RANCAT juv 0.1/tn, 4 SIRINT 0.4/tn
6 June 2009 Too shallow, 0 traps
6 September 2009 Too shallow, 0 traps
2010 FWS- Began drawdown 3/3. Unit dry by 6/1. Unit not reflooded - well broken. Reflooded 11/1.
9 April 2010 Too shallow, 0 traps
17 June 2010 dry
1 September 2010 dry
2011 FWS - July drawdown, reflooded late Oct.
21 March 2011 Too shallow, 0 traps
11-13 June 2011 20 MT/40 tn 1 HYLCIN tad 0.025/tn, 1 RANSPH tad 0.025/tn, 1 RANCLA tad 0.025/tn, 5 NERRHO 0.125/tn, 3 NERFAS 0.075.tn, 2 FARABA 0.05/tn
22 September 2011 Too shallow, 0 traps
49
Pond J. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS- Began drawdown 5/20. Mostly dry by 6/30. Unit sprayed 8/14. Applied 20 pints of Ultrablazer over unit using 10 gallons of water per acre.
2009 FWS- Drawdown begun 3/6. Dry at wcs by 4/8, but large pool still present. Pools remained through August. Disked all except remnant pool in end of August. Began pumping 9/16. Unit full by 9/21 and at top of wcs (from rain) by 10/16.
26-27 March 2009 10 MT/10 tn 201 RANSPH tads 20.1/tn, 1 RANCAT juv 0.1/tn, 2 SIRINT 0.2/tn
8-11 June 2009 20 MT/60 tn 7 SIRINT 0.175/tn, 7 NERRHO 0.175/tn, 1 NERFAS 0.017/tn, 1 NERERY 0.017/tn, REGGRA 0.017/tn
6 September 2009 Too shallow, 0 traps
2010 FWS- Began drawdown 3/3. Unit dry by 6/1. Unit reflooded beginning 9/8. Water evaporated over much of unit, then reflooded 2/3.
10-14 April 2010 20 MT/60 tn 8 RANSPH tads 0.133/tn, 1 SIRINT 0.017/tn, 1 NERRHO 0.017/tn, 1 NERFAS 0.017/tn
17 June 2010 Too shallow, 0 traps
1 September 2010 dry
2011 FWS - Drawdown end March, partial mow in Sept, reflooded mid-Oct.
21-23 March 2011 20 MT/40 tn 2 RANSPH tads 0.05/tn, 1 NOTVER ad 0.025/tn, 4 SIRINT 0.1/tn, 1 NERRHO 0.017/tn, 3 NERFAS 1.075/tn
9 June 2011 dry
22 September 2011 dry
50
Pond K. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 3/10. Dry by 4/24. Unit reflooded shallowly 11/3 - 11/5.
2009 FWS- Drawdown begun 6/5, largely dry by 8/6. Unit sprayed 9/1 with 1 pt./ac. UltraBlazer.
26-27 March 2009 10 MT/10 tn 1 RANSPH ad 0.1/tn
6-10 June 2009 20 MT/60 tn 9 RANCLA tads 0.15/tn, 1 SIRINT 0.017/tn, 10 NERRHO 0.6/tn, 2 NERFAS 0.033/tn, 1 FARABA 0.017/tn
6 September 2009 Too shallow, 0 traps
2010 FWS- Began drawdown 3/3. Unit dry by 6/1. Disked 6/21 and reflooded 7/6. Visual inspection 10/1, unit mudflat. Flooded 10/29.
12-14 April 2010 20 MT/40 tn 23 RANSPH tads 0.575/tn, 1 SIRINT 0.025/tn, 3 NERRHO 0.075/tn, 1 NERFAS 0.025/tn
17 June 2010 Too shallow, 0 traps
1-4 September 2010 40 MT/120 tn 70 HYLCIN tads 0.583/tn, 1 HYLCIN ad 0.008/tn, 3 RANSPH ad 0.025/tn, 14 SIRINT 0.117/tn, 2 NERRHO 0.017/tn
2011 FWS - Early drawdown, partial mow, reflooded late Oct.
21 March 2011 dry
9 June 2011 dry
22 September 2011 dry
51
Pond L. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS- Begin drawdown 3/10. Nearly dry by 6/20. Unit disked 6/27 - 7/8. Reflooded 7/21 - 7/25. Unit dried somewhat and flushed again with water 10/14 - 15.
2009 FWS-Drawdown begun 3/6. Dry at wcs by 4/8, but large pool still present. Pools remained through August.
26 March 2009 Too shallow, 0 traps
6 June 2009 Too shallow, 0 traps
6 September 2009 Too shallow, 0 traps
2010 FWS-Began drawdown 5/12. Unit dry by 7/2. Reflooded 9/14.
10-13 April 2010 20 MT/60 tn 61 RANSPH tads 1.02/tn, 5 NERRHO 0.08/tn, 6 NERFAS 0.1/tn
17 June 2010 Too shallow, 0 traps
1 September 2010 dry
2011 FWS - - Drawdown end March, partial disk, remainder mowed (lower area), reflooded mid-Aug.
21-23 March 2011 20 MT/40 tn 13 RANSPH tads 0.235/tn, 1 NERRHO 0.025/tn, 1 NERFAS 0.025/tn
9 June 2011 Too shallow, 0 traps
23-25 September 2011 20 MT/40 tn 2 HYLCIN tads 0.05/tn, 2 RANSPH ad 0.05/tn, 1 RANCAT juv 0.025/tn,
52
Pond M. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-No boards pulled but unit dried through evaporation before 7/31. Unit disked 7/31 - 8/4? Unable to reflood. As of 11/6, unit still dry.
2009 FWS-Drawdown begun 6/5. Had largely dried by 6/22, then large areas shallowly flooded due to summer rains. Unit largely reflooded by 10/16 (though only shallowly).
26 March 2009 Not trapped
6 June 2009 Not trapped
6 September 2009 Not trapped
2010 FWS- Began drawdown 6/1. Finally flooded 2/4/11.
9 April 2010 Not trapped
17 June 2010 Not trapped
1 September 2010 Not trapped
2011 FWS - Drawdown mid-May, mowed
22-25 March 2011 20 MT/60 tn 203 RANSPH tads 3.38/tn, 1 SIRINT 0.175/tn, 2 NERERY 0.033/tn
9 June 2011 dry
22 September 2011 dry
53
Pond N. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-No boards pulled. Unit retained some water throughout summer, particularly south end.
2009 FWS-Water held throughout summer with some evaporation occurring. Old levee between units exposed but more than 50% of unit remained flooded.
25-26 March 2009 10 MT/20 tn 0 amphibians
6 June 2009 Too shallow, 0 traps
6 September 2009 Too shallow, 0 traps
2010 FWS-No boards removed but had dried by evaporation by 10/5. Some water throughout the winter, but still not at full pool by 1/1/11.
7 April 2010 Too shallow, 0 traps
17-19 June 2010 20 MT/40 tn 0 amphibians. 5 NERRHO 0.125/tn, 1 NERFAS 0.025/tn
1-3 September 2010 20 MT/40 tn 0 amphibians
2011 FWS - No mgmt
21-24 March 2011 Too shallow, 0 traps
11-13 June 2011 20 MT/40 tn 2 RANCLA tads 0.05/tn, 1 NERRHO 0.025/tn
23-25 September 2011 20 MT/40 tn 6 RANCLA juv 0.15/tn,
54
Pond P. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-No boards pulled. Unit retained water throughout summer. (Dropped approximately 1' in depth.)
2009 FWS-Water held throughout summer with some evaporation occurring. Pulled 2 boards in late July to facilitate wood duck trapping. Did not replace.
26 March 2009 Not trapped
6 June 2009 Not trapped
6-9 September 2009 10 MT/60 tn 5 RANCAT juv 0.083/tn, 31 SIRINT 0.517/tn, 5 NERRHO 0.083/tn, 1 NERFAS 0.017/tn
2010 FWS-No boards removed but had dried by evaporation by 10/5. Some water throughout the winter, but still not at full pool by 1/1/11.
10-12 April 2010 20 MT/40 tn 1 RANCAT tad 0.025/tn, 1 SIRINT 0.025/tn, 7 NERRHO 0.175/tn
17-18 June 2010 20 MT/20 tn 2 SIRINT 0.1/tn, 1 AGKPIS 0.05/tn, 2 NERRHO 0.1/tn, 3 NERFAS 0.15/tn
2-5 September 2010 20 MT/60 tn 2 RANSPH ad 0.033/tn, 1 NERRHO 0.017/tn, 1 NERFAS 0.017/tn
2011 FWS - No mgmt
21-24 March 2011 10 MT/30 tn 1 SIRINT 0.033/tn
11-13 June 2011 20 MT/40 tn 2 HYLCIN tads 0.05/tn, 7 RANSPH tads 0.175/tn, 3 RANCLA 0.075/tn, 1 SIRINT 0.025/tn, 1 AGKPIS 0.025/tn, 1 NERFAS 0.025/tn, 2 FARABA 0.05/tn
23-25 September 2011 20 MT/40 tn 1 HYLCIN tad 0.025/tn, 5 RANSPH tads 0.125/tn, 3 RANCAT 0.075/tn, 2 ACRCRE tads 0.05/tn, 1 SIRINT 0.035/tn
55
Pond PP. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS- Unit evaporated somewhat throughout the summer, exposing mud flats, then reflooding following hurricanes Gustav and Ike.
2009 FWS-Waterheld throughout summer with very little evaporation.
26 March 2009 Not trapped
6 June 2009 Not trapped
8-9 September 2009 15 MT/15 tn 2 SIRINT 0.133/tn
2010 FWS-Held water throughout summer, in spite of severe drought. Pulled boards 9/23 to clear wcs. Reboarded 10/5, but beaver had kept unit from fully draining.
10 April 2010 Not trapped
17 June 2010 Not trapped
1 September 2010 Not trapped
2011 FWS - No mgmt
56
Pond Q. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 5/20. Unit mostly dry by 6/20. Unit sprayed with UltraBlazer 8/13. Applied 17 pints of chemical total over unit with 10 gallons of water/acre. Unit reflooded shallowly 11/3 - 11/5.
2009 FWS-Drawdown begun 3/6. Nearly dry by 4/8, but rains in May reflooded. Essentially dry by 6/25. Decided not to disk. Unit reboarded 9/24 and flooded by 10/16.
26 March 2009 Not trapped
6 June 2009 Not trapped
6 September 2009 Not trapped
2010 FWS-Held water for shorebird drawdown. Added additional water 6/28. Began drawdown 7/19. Unit dry prior to 10/5. Reflooded beginning 10/7.
10 April 2010 Not trapped
16-19 June 2010 20 MT/60 tn 7 HYLCIN tads 0.117/tn, 63 RANCAT tads 1.05/tn, 1 SIRINT 0.017/tn, 5 NERRHO 0.083/tn, 6 NERFAS 0.01/tn, 1 NERERY 0.0175/tn, 1 FARABA 0.0175/tn
1 September 2010 Dry
24-25 March 2011 20 MT/20 tn 5 RANSPH tads 0.25/tn
9-10 June 2011 dry
25-26 September 2011 20 MT/20 tn 2 HYLCIN tads 0.1/tn
57
Pond R. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011. This pond was not part of the original study but was trapped several times during 2009-2011.
Dates Treatment Species & numbers
2009 FWS-Water held throughout summer with very little evaporation occurring.
26 March 2009
7-9 June 2009 29 MT/ 87 tn 2 RANCAT juv 0.023/tn, 4 NERRHO 0.046/tn, 2 NERFAS 0.023/tn, 1 NERERY 0.023/tn
8-9 September 2009 25 MT/25 tn 1 NERRHO 0.04/tn, 1 AGKPIS 0.04/tn
2010 FWS- Pulled no boards, but unit nearly dry by 10/5. Reflooded by rainwater, nearly full by 1/1/11.
10 April 2010 No minnow traps
17 June 2010 No minnow traps
1-3 September 2010 8 MT/16 tn 1 NERRHO
2011 FWS - No mgmt
21-24 March 2011 10 MT/30 tn 34 RANSPH tads 1.13/tn, 5 SIRI NT 0.167/tn
9-11 June 2011 15 MT/30 tn 1 SIRIN T 0.03/tn, 2 NERRHO 0.067/tn, 1 FARABA 0.03/tn
23-25 September 2011 20 MT/40 tn 1 HYLCIN juv 0.025/tn, 3 RANSPH tads 0.075/tn, 1 RANCAT juv 0.025/tn, 3 SIRI NT 0.1/tn
58
Pond S. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 5/20. Unit mostly dry by 6/20. Sprayed with UltraBlazer 8/13, Applied 19 pints of chemical total with 10 gallons of water/acre. Unit reflooded 10/8 - 10. Water added 11/3 - 5 in order to flood Q.
2009 FWS- Drawdown begun 3/6. Unit dry by 4/8, but reflooded by backflowing in mid-May. Ready to disk by 7/27. Disked 8/21. Reflooded beginning 9/29. Fully flooded by 10/5.
26 March 2009 Not trapped
6 June 2009 Not trapped
6 September 2009 Not trapped
2010 FWS-Added water 6/28. Held water until 7/7 when began shorebird drawdown. Dry at wcs by 8/2, allowed to evaporate until 9/14 when began reflooding. Added more water in early Oct. to flood Q.
10 April 2010 Not trapped
16-18 June 2010 20 MT/40 tn 3 RANCAT tads 0.075/tn, 1 RANCLA tad 0.025/tn, 3 HYLCIN tads 0.075/tn, 1 NERRHO 0.025/tn, 2 NERFAS 0.05/tn
1 September 2010 dry
2011 FWS - Drawdown mid-May, disked, reflooded early August, pulled down again beginning of Sept.
21 March 2011 dry
11 June 2011 dry
23-25 September 2011 20 MT/40 tn 1 HYLCIN tads 0.025/tn, 3 SIRINT 0.075/tn
59
Pond T. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 3/10. Unit dry at structure by 4/18, but backfilled from ditch in late May. Nearly dry by 6/20. Disked 6/25 - 27. Unit reflooded 7/15 - 7/22. By 11/6, approximately 1/2 of unit with no standing water.
2009 FWS-Drawdown begun 3/6. Equalized with ditch by 3/20. Pools finally dry by 6/24. Boards replaced 9/24 to catch rainwater. Fully flooded by late October.
26-27 March 2009 10 MT/10 tn 1 RANCAT juv 0.1/tn, 53 RANCLA tads 5.3/tn
6 June 2009 dry
6 September 2009 dry
2010 FWS- Began drawdown 5/12. Unit dry by 7/2. Sprayed 7/16. Reflooded 11/1.
10-12 April 2010 20 MT/40 tn 20 RANSPH tads 0.5/tn, 2 RANCAT juv 0.05/tn, 1 BUFFOW juv 0.025/tn, 2 NERFAS 0.05/tn
16-18 June 2010 20 MT/40 tn 11 RANCAT tads 0.275/tn, 30 NERRHO 0.75/tn, 1 NERFAS 0.025/tn
1 September 2010 dry
2011 FWS - Drawdown mid-May, disked, reflooded mid-August
24-25 March 2011 20 MT/20 tn 3 RANSPH tads 0.15/tn, 2 RANCAT juv 0.1/tn, 3 RANCLA tads 0.15/tn
11 June 2011 dry
23-25 September 2011 20 MT/40 tn 1 HYLCIN tad 0.025/tn, 1 NERCLY 0.025/tn, 1 FARABA 0.025/tn
60
Pond U. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS- Began drawdown 3/17. Unit dry by 4/18. Some backflow 5/1, but very little. Unit disked 7/15 - 17. Unit reflooded 8/4 - 8/13. More water added 8/18 - 22 to fill unit W.
2009 FWS-Water held until 7/27 when shorebird drawdown began. (Water had gone down by approximately 9" due to evaporation prior to this.) Progressed nicely, added approximately 1.5' of water 9/10 since unit was nearly dry. Rain began 9/13 and flooded unit to unusable point.
26 March 2009 Not trapped
9-11 June 2009 20 MT/20 tn 13 HYLCIN tads 0.325/tn, 1 RANCLA tad 0.025/tn, 1 NERRHO 0.025/tn, 1 FARABA 0.025/tn
6 September 2009 dry
2010 FWS- Drawdown began 3/31. Unit dry by 4/16. Boards replaced 10/5, and flooded 10/28.
10 April 2010 Dry
17 June 2010 dry
1 September 2010 dry
2011 FWS - Drawdown mid-May, disked, reflooded late July, pulled down again early August
21 March 2011 dry
11 June 2011 dry
61
Pond V. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS-Began drawdown 3/10. Unit mostly dry by 4/18, but backfilled from ditch 5/20. Nearly dry by 6/20. Boards replaced 10/3. Unit flooded by rainwater.
2009 FWS- Drawdown begun 6/5. Never completely dried (pool along northern levee). Unit sprayed with 1 pint/acre of UltraBlazer on 9/2. Boards replaced 9/24, unit fully flooded (from rain) by late October.
25-27 March 2009 10 MT/20 tn 0 amphibians
9-11 June 2009 20 MT/40 tn 0 amphibians, 2 NERRHO 0.05/tn
6 September 2009 dry
2010 FWS- Drawdown began 3/3. Unit dry 6/1. Disked 6/24 and reflooded 7/12. Began shorebird drawdown 8/2. Dry by 10/5, Reflooded10/29.
12-13 April 2010 20 MT/20 tn 141 RANSPH tads7.05/tn, 1 SIRINT 0.1/tn
17 June 2010 Not trapped
4-5 September 2010 10 MT/10 tn 38 HYYCIN tads 3.8/tn, 5 SIRINT 0.5/tn, 6 NERRHO 0.6/tn
2011 FWS - Early drawdown, reflooded early Sept
21 March 2011 dry
11 June 2011 dry
23 September 2011 dry
62
Pond W. Dates are treatment dates and the minnow trap (MT and Trap nights: tn) dates during the nine sampling sessions 2009-2011.
Dates Treatment Species & numbers
2008 FWS- Began drawdown 3/10. Unit dry at structure by 5/1. Several large pools still remained until 6/30. Unit disked 7/28 - 31. Reflooded 8/18 - 22.
2009 FWS-Water held until 8/14 when shorebird drawdown began. Rains prevented adequate drawdown. Unit reboarded 10/16 and full by end of October.
26 March 2009 Not trapped
6 June 2009 Not trapped
6 September 2009 Not trapped
2010 FWS - Began drawdown 6/1. Mostly dry by 8/2.
10 April 2010 Not trapped
17 June 2010 dry
1 September 2010 dry
2011 FWS - Drawdown mid-May, partial mow
24-25 March 2011 20 MT/20 tn 1 RANSPH ad 0.05/tn, 2 RANSPH tads 0.1/tn, 7 PSECRU tads0.35/tn, 2 RANCAT juv 0.1/tn
11-13 June 2011 20 MT/40 tn 0 amphibians
23 September 2011 Water depth too shallow
63
Appendix 3. Summary of frog morphometrics from Coldwater NWR.
Sample sizes for four of the 10 species of frogs encountered on the refuge that were large enough to evaluate statistically for sexual size dimorphism and body sizes of adults, juveniles, and metamorphs. These data are summarized below. Figures 1-4 illustrate the relationship of body mass with snout-vent length. Sample sizes for the remaining species were 3 or fewer.
Descriptive statistics of four species of frogs on Coldwater NWR. Numbers are mean+1 standard deviation, minimum-maximum, and sample size in parentheses.
Species Snout-vent Length (mm) Mass (g) Bufo fowleri
Males 57.24+3.53 52-64 (29)
18.26+2.80 14.0-26.1 (29)
16-21 (10) 0.61+0.30
11-14 (15) 0.27+0.06
0.2-0.4 (15) Hyla cinerea
6.76+1.18 5.7-8.7 (13)
5.93+3.20 1.05-9.4 (3)
1.05+0.16 0.78-1.38 (57)
161.80+95.98 56.9-260 (5)
22.84+15.04 4.9-63.7 (58)
7.79+1.33 6.2-10.0 (18)
20.79+6.17 9.9-27.8 (15)
7.82+3.95 4.6-14.5 (5)
2.75+0.62 2.0-4.0 (11)
64
Figure 1. Relationship of body mass with snout-vent length of Bufo fowleri on Coldwater NWR.
Figure 2. Relationship of body mass with snout-vent length of Hyla cinerea on Coldwater NWR.
65
Figure 3. Relationship of body mass with snout-vent length of Rana catesbeiana on Coldwater NWR.
Figure 4. Relationship of body mass with snout-vent length of Rana sphenocephala on Coldwater NWR.
66
Appendix 4. Siren intermedia tagged with PIT tags at Coldwater National Wildlife Refuge.
Date Pond SVL Tail Lth Total Lth Mass PIT Tag number