Félicitations aux gagnants des prix pour étudiants de la dernière assemblé générale annuelle.
|l`Année:||Lauréates / Lauréats:||Titre et Résumeé:|
|Title: On The Road Again: Measuring the Effectiveness of Mitigation Structures for Reducing Reptile Road Mortality|
Authors: James Baxter-Gilbert, Dr. David Lesbarreres, and Dr. Jacqueline Litzgus
Abstract: Many reptile populations are negatively impacted by roads, especially because seasonal migratory movements increase individual encounters with traffic. The Highway 69/400 corridor, connecting southern and northern Ontario, runs along the eastern Georgian Bay Coast, one of Canada’s richest areas of reptile biodiversity. A section of new 4-lane highway has been designed to include mitigation structures (e.g., eco-passages, fences) intended to lessen the detrimental effects this major roadway poses to numerous Species-at-Risk (SAR) reptiles. Using a Before-After-Control-Impact-Paired (BACIP) study design, we will quantify reptile road mortality present on the existing, non-mitigated 2-lane highway (in spring and summer 2012) and compare it to mortality on the new, mitigated 4-lane highway (in spring and summer 2013). In both years of the study, a control site without any mitigation measures will also be monitored. If the exclusion structures (e.g., fences) of the new highway are effective, animals should be prevented from accessing the road and we should therefore observe a reduction in road mortality. Radio telemetry, automated PIT tag readers, and wildlife cameras will be used to monitor reptile movements around and under the road via population connectivity structures (e.g., eco-passages). Additionally, a “willingness to utilize” experiment will be conducted, which will assess turtle behaviour in response to the eco-passage. If the population connectivity measures are effective, movements between habitats on either side of road, and use of the eco-passages are expected. Conclusions drawn from our study will allow development of recommendations for future road mitigation structures to reduce road mortality, and counteract the decline of reptile biodiversity.
|2011||Julia L. Riley|
Pamela Rutherford with Julia
|Title: Should i stay or should i go? The influence of environmental factors on Chrysemys picta hatchling overwintering strategy.|
Authors: Julia L. Riley, Glenn Tattersall, and Jacqueline D. Litzgus
Abstract: In northern temperate areas, Chrysemys picta hatchlings spend their first winter either submerged in water after fall nest emergence, or within their natal nest chamber. The occurrence of these two strategies varies among populations throughout the species' range, and temporally within the same population; however, the natural factors that determine the strategy employed by a given clutch are not well understood. Subzero nest temperatures above -4°C can be survived by hatchlings using freeze-tolerance, but low nest temperatures like those found in the temperate north can only be survived in a supercooled state. If overwintering strategy maximizes winter survival and is cued by environmental factors, then northern hatchlings should remain in nests when the environment promotes supercooling. Clutches that overwinter in-nest should experience lower fall nest temperatures, soil moisture and vegetation cover, higher nest soil organic content, and smaller nest soil particle size than clutches that experience fall nest emergence. We are testing this hypothesis over two field seasons in Algonquin Park, Ontario. In summer 2010, 26 C. picta nests were caged and a data logger was placed in each to record temperature. Soil texture was quantified for each nest. Nest microhabitat variables were recorded at oviposition and monthly during incubation. In the fall of 2010, 12% of the nests emerged. From April to May 2011, spring emergence was monitored and overwinter survival was 41% (N = 18). None of the environmental factors examined to date appear to influence overwintering strategy; however, additional environmental factors, such as percent oxygen, are currently being monitored, and 27 caged nests will be followed over the 2011-12 winter. Knowledge of hatchling C. picta overwintering strategies is predominately based on laboratory studies; our study will contribute to understanding this phenomenon in nature.
|2010||Joël Leduc |
Department of Biology, Laurentian University
|Title: Ecology of Herpetofaunal Populations in Tailings Wetlands in Sudbury, Ontario. |
Authors: Joël C. Leduc*, Kristen J. Kozlowicz, Jacqueline D. Litzgus et David Lesbarrés
Abstract: Since the 1920's, Sudbury, Ontario has emerged into one of the world's largest metal producers. The mining and smelting industries have left a devastating ecological footprint on the Sudbury landscape with metal-contaminated substrates and acidified waters near the smelting facilities and tailings wetlands. We tested the hypothesis that the perturbations caused by smelting activities have a negative effect on ecological aspects of amphibian and reptile populations on the tailings wetlands of Xstrata Nickel. We examined the differences in herpetofaunal amphibian and reptile abundance, diversity, biomass, body length and reproduction among three impacted wetlands situated at Xstrata Nickel, Falconbridge, Ontario in comparison with a non-tailings wetland located at the Laurentian Conservation Area, Sudbury, Ontario. Day and night field surveying and sampling were performed two to three times per week for an entire breeding season (22 May - 24 September, 2009). We found significant differences in abundance, biomass, and reproduction, but no differences in species richness or body size in a target species, the green frog (Lithobates clamitans), among sites. The three impacted sites demonstrated lower abundance and biomass than the control site, and fewer species were reproductively active. Our findings indicate that the tailings wetlands may not be able to sustain the large dynamic communities present at non-tailings wetlands, and that herpetofaunal communities may be negatively impacted within the tailings wetlands.
|2009||Godwin Okonkwo |
University of Alberta
|Title: The use of small ephemeral wetlands by amphibians in the mixedwood forest of boreal Alberta. |
Authors: Godwin E. Okonkwo*, Cynthia A. Paszkowski and Brian R. Eaton
Abstract: Amphibians are currently experiencing a population decline due to several factors including habitat loss. Identifying what constitutes amphibian habitat in the mixed wood forest landscape will provide a critical tool for managing populations. Most conservation plans for amphibians ignore small ephemeral watersheds because of their size and temporary nature. Furthermore, there have been limited studies on amphibian use of these habitats. We carried out a study to identify if and how amphibians use small ephemeral wetlands (< 0.1ha) on land leased by Daishowa Marubeni International Ltd. within the Peace River Forest Management Area of northwestern Alberta. Twenty-seven small ephemeral wetlands (< 0.1ha) were sampled every two weeks using time-constrained visual encounter surveys for all life stages of amphibians, from May to August, 2008. During each survey, water depth, hydroperiod, temperature, pH and canopy cover of the ponds were also measured. Amphibians were observed at the water surface, pond bottom, under submerged debris, shoreline and riparian areas. A total of 1,105 amphibians including Lithobates sylvaticus (Rana sylvatica), Anaxyrus boreas (Bufo boreas) and Pseudacris maculata were captured in 19 wetlands. Breeding was observed with egg masses and tadpoles occurring in 14 wetlands. Over 68% of the animals found were young-ofthe-year. Wetlands with amphibians were characterised by < 40% canopy cover, while > 60% canopy cover was observed at wetlands without amphibians. Temperature and pH were significantly higher in wetlands with amphibians present. Regression analysis indicated that pH, canopy cover, temperature and hydroperiod significantly influenced amphibian presence and breeding at these wetlands. Our study demonstrates that amphibians use small ephemeral wetlands at different stages of their life cycles. The value of these wetlands should not be under-estimated because of their small size, and the absence of water at the time of operational planning. Based on the use of these habitats by amphibians documented by our study, incorporating small wetlands into forestry and conservation plans will contribute to the preservation of amphibian populations.
|2008||Nicholas Cairns |
|Title: The Smooth Green Snake and the Northern Red-bellied Snake: A comparison of the ecology of two small, terrestrial, northern snakes. |
Authors: Nicholas Cairns, Pamela Rutherford
Abstract: The smooth green snake (Liochlorophis vernalis) and the northern red-bellied snake (Storeria occipitomaculata occipitomaculata) are small, terrestrial colubrid snakes reaching the extremes of their distributions in southwestern Manitoba. While both species are constrained by short, active seasons they differ substantially in morphology and reproductive mode (L. vernalis is oviparous and S. occipitomaculata is viviparous). The aim of this study is to compare the ecology of these two species in Manitoba by asking two specific questions. First, do these two northern snakes occupy similar ecological niches? Second, what are the local hibernation characteristics in comparison to their hibernation sites at other localities? We addressed these questions with a mark-recapture study using active searching and searching under artificial cover. Local hibernation patterns were determined using drift fences and trapping, active searching, and implantation of temperature data loggers at the hibernation sites. The study was conducted from spring 2007 to summer 2008 in southwestern Manitoba, Canada. Approximately equal numbers of both species were located, although hibernation characteristics were determined only for S. occipitomaculata. Sexual dimorphism was evident only in L. vernalis (females were larger) and gravid females of both species were last captured in mid-July. S. occipitomaculata were captured at lower temperatures and tended to be captured in habitat more closely associated with water although in the third week of June there appeared to be a pulse of activity in more xeric prairie and associated habitat. L. vernalis were almost always associated with prairie and prairie ecotone habitat types. S. occipitomaculata used abandoned ant nests for hibernation sites and were active at these sites until September 25, 2007. Hibernation site characteristics will be determined in spring 2008.
|2007||Anita H. Melnyk |
|Title: The influence of data partitioning on Bayesian phylogenetic inference of the Lithobates catesbeianus species group. |
Authors: Anita H. Melnyk* and Stephen C. Lougheed
Abstract: Although many phylogenetic studies routinely employ Bayesian inference, few have examined the effects of different partitioning strategies on tree topology and posterior probability support. Partitioned Bayesian analyses of 1175 bps of mitochondrial DNA sequence were used to investigate the evolutionary affinities of the Lithobates catesbeiana species group of frogs. Fragments of mitochondrial 16S, tRNAleu and ND1 from 14 individuals encompassing all seven species were used in analysis with four different partitioning strategies (1. all data combined; 2. RNA and protein coding genes; 3. each gene separately; 4. stems and loops in RNA coding genes, ND1 3rd codon, ND1 1st and 2nd positions). Comparison of Bayes factors showed that no partitioning strategy was significantly better than any other although different strategies did yield trees with slightly different topologies and varied support values. This result is potentially due to the incorporation of random error associated with the small partition sizes of more complex partitioning strategies. Six of the seven species form an unresolved basal polytomy in the tree determined by the best partitioning strategy. To increase resolution of the phylogeny additional data need to be included. While there remain many areas of exploration in Bayesian analysis, including evaluation of the effects of partitioning and model choice, this study points to how more sophisticated analyses can more fully capture how evolution proceeds for phylogenetically-informative markers.
|2006||Isabelle Deguise |
University of British Columbia
|Title: Movement patterns of adult western toads, Bufo boreas, in fragmented landscapes |
Abstract: In fragmented landscapes, dispersal ability and movement behaviour are critical factors determining the persistence of a threatened species. I used radio-telemetry to follow the movement patterns of adult western toads in a fragmented landscape. Toads were experimentally translocated into either forest patches or clear-cut patches, and their movements followed on a daily basis. Preliminary results and conclusions will be shown.
|2005||Paula Duarte |
University of Ottawa
|Title: Early exposure to 17±-ethinylestradiol alters sex ratios and gonadal morphology of developing leopard frogs (Rana pipiens). |
Authors: Paula Duarte, Natacha Hogan, Bruce Pauli, Michael Wade, David R. S. Lean, Vance L. Trudeau
Abstract: Environmental estrogens have been shown to alter gonad development, causing sex reversal, feminization or the intersex condition in some amphibian species. Our objective was to (1) examine normal sexual differentiation during tadpole development and metamorphosis in R. pipiens and (2) determine if the contraceptive ethinylestradiol (EE2) can have long-term effects on gonad morphology and sex ratios at metamorphosis. Control tadpoles were exposed to acetone (0.004%) vehicle throughout the experiment. Exposure to EE2 (5nM) in water began at Gosner stage 26(hind limb bud development). After an early, short-term exposure (STE; approximately 3 weeks) until stage 30, a subset of tadpoles was transferred to control water while a chronic exposure (CE) continued until both groups reached metamorphic climax (stage 42). Histological analysis of the gonads at stage 42 revealed that the sex ratio in the control group was 1:1 (female:male). STE shifted the sex ratio towards females and increased the incidence of intersex individuals; the female:male:intersex ratio was 1:0.1:0.2. For CE, the sex ratio was 1:0.6:0.7 which suggests that the timing and length of estrogen exposure can influence the resulting sex ratios. These results indicate that a short exposure to waterborne EE2 during the critical period of gonadal development can permanently alter sex ratios and induce intersex in a native Canadian amphibian. Supported by U-Ottawa, NSERC, Environment Canada