In Ontario, the common snapping turtle, Chelydra serpentina, is listed as Special Concern and is at risk of decline. These long-lived organisms are particularly susceptible to anthropogenic threats owing to delayed sexual maturity, low recruitment and reliance on low adult mortality. Threats facing this species include road mortality and habitat loss and/or destruction. These threats are anecdotally evident within Cootes Paradise Marsh, a highly urbanized river-mouth coastal marsh located in a heavily urbanized region at the western end of Lake Ontario. Straddling Dundas and Hamilton, the wetland is bisected by Cootes Drive, a four-lane highway (maximum speed 80 km/h) that has resulted in fatal collisions with wildlife. We re-analyzed data from previous capture-mark-recapture studies and determined that the snapping turtle population has declined by almost 90% from 1985 to 2002. Using road mortality survey data collected by citizen science group Dundas Turtle Watch, we determined that some of this decline can be attributed to road mortality. Through radio tracking, we also found that the population remains at risk to road mortalities because their home ranges overlap surrounding roads. Besides the direct negative effect of mortality, roads impart broader and additional unintended consequences by hindering turtles’ access to critical nesting and overwintering habitat. We acquired digital orthophotos to assess changes in availability of nesting habitat, which is crucial for recruitment and population maintenance. Potential nesting habitat decreased by almost 50% between 1934 and 2010. Through nest surveys conducted in 2017, we determined that there is currently disproportionate use of artificial gravel mounds for nesting. For overwintering purposes, snapping turtles appear to be using a wide range of habitat types within the upland terrestrial matrix of the wetland ecosystem. We also confirmed that sites used for overwintering did not cool below inhibiting temperatures between early December and end of March. This study illustrates the toll that road mortality can have on urbanized herpetofauna populations and highlights the importance of ensuring that recovery plans focus on restoring both the quantity and quality of nesting and overwintering habitats. / Thesis / Master of Science (MSc) / Common snapping turtles (Chelydra serpentina) exhibit “slow” life history traits which make them particularly vulnerable to human activities, such as urbanization. In this thesis, I used demographic and road mortality information to provide evidence that the population of snapping turtles living in the degraded Cootes Paradise Marsh ecosystem has substantially declined over the past three decades. I also assessed current availability of nesting and overwintering habitat that are both essential for maintaining a viable population of snapping turtles. My results highlight the devastating effects road mortality can impart on long-lived freshwater reptiles, and cautions against further modification or destruction of their critical habitat.

Synalpheus shrimp species of the gambarelloides group are the only marine organisms displaying the highest level of social functioning, eusociality. Their social hierarchies are equally complex compared to the reproductive abnormalities that have been recently discovered. For instance, snapping shrimp of the genus Synalpheus were thought to be gonochoric, i.e. developing as independent sexes, until scanning electron microscopy studies revealed intersexed gonopores in several species. This project analyzed both the species composition, and accompanying reproductive structures, of Synalpheus spp. (Caridea: Alpheidae) comprised of densely aggregating communal and pair-living colonies in the Florida Keys, Florida. Colonies of pair-living and communal Synalpheus spp. were observed from hosts Spheciospongia vesparium and Spongia sp. from hard bottom assemblages of the Florida Reef Tract in order to assess differing population structures. Comparisons were made of the measures of overall and relative abundance, frequency by species and sex category, and variation in growth by species and sex category, for each individual colony. We then used scanning electron microscopy (SEM) images to determine the secondary sexual characteristics of three species (Synalpheus brooksi, S. herricki, and S. cf. herricki) which range in social behavior. Species were widely consistent in both host choice and distribution, across all sampling areas. The abundance of communal species Synalpheus brooksi was much greater than expected at all sites, in comparison to previously published work. While Synalpheus longicarpus was reported at higher frequencies in prior studies, our results yielded a much lower frequency of this species, often found in pairs, rather than dense aggregations. Average sizes of ovigerous and non-ovigerous individuals in dense colonies of Synalpheus brooksi and S. pectiniger did not differ significantly. However, total body length of individuals differed within species groups, specifically related to sex and presence of ova. Within colonies of S. brooksi, mid-development, or ‘transitional’ individuals, were discovered in nearly all populations. However, the reproductive and social function of these individuals displaying mixed sexual characteristics could not be determined from this study. Individuals of S. brooksi displaying ‘transitional’ external morphology, i.e. masculine abdominal pleura paired with clutches of eggs, displayed higher incidences of intersex gonopores per colony than did conspecific non-ovigerous and ovigerous individuals. These results suggest that colonies of S. brooksi may be comprised of a subset of helpers, or individuals undergoing a transitional sexual development phase, similar to prior published findings of intersexed helpers among eusocial colonies (Toth and Bauer 2007). In comparison to S. brooksi colonies, nearly all colonies of S. herricki and S. cf. herricki were composed of intersex individuals. In conjunction with previous instances documented in eusocial Synalpheus paraneptunus groups, the data provide substantial evidence of intersexing at all levels of social organization in Synalpheus spp. (pair living, communal, and eusocial). These findings nonetheless provide a clearer picture of how social structure and life history influence adaptation of a particular reproductive strategy. Quantifying features of Spheciospongia vesparium populations and comparing results to neighboring hosts, such as Spongia sp., provided evidence for potential influences of host choice, and variation in growth and reproductive capacity temporally and spatially. These observations of species’ growth patterns and abundances contribute greatly to our understanding of life history of Synalpheus spp., and, furthermore, adaptation of social organization.

The aim of this thesis was to analyze the interactions between stallion and his offspring in two socially natural herds of Exmoor ponies. These interactions have not been thoroughly revised yet. We studied and compared aggressive and friendly interactions, snapping of the foals and play behavior between the individuals, with the main focus on the foal-stallion interactions. The results suggest, that the stallion is the most common adult recipient of foal behaviour and can play an important role in the foals motorical and social development.

The focus of this research was the spontaneous magnetic alignment responses of animals. We show that snapping turtles (Chelydra serpentina) and crayfish (Cambarus sciotensis) spontaneously align their body axes relative to the magnetic field. In snapping turtles, this response is sensitive to low-level radio frequency fields, consistent with a mechanism involving a light-dependent radical pair mechanism. Findings from the turtle experiments also suggest that the Earth's magnetic field plays an important role in encoding spatial information in novel surroundings, and may help to organize multiple locales into a 'mental map' of familiar space. Given the importance of magnetic input in many aspects of spatial behavior, another important finding was that magnetic alignment of yearling turtles was disrupted by high levels of maternally transferred mercury, an industrial waste product found at high levels in some fresh water ecosystems. In crayfish, we investigated the effects of ectosymbionts (Annelida: Branchiobdellida) on magnetic alignment responses. Interestingly, the response of crayfish to magnetic cues parallels the complex symbiotic interaction between crayfish and their ectosymbiotic worms, which changes from mutualistic to parasitic with increasing worm density. Our working hypothesis was that these changes in spatial behavior may increase or decrease contact to other crayfish, and therefore increase or decrease transmission rates. Next, to address the ontogeny of the SMA, we attempted to replicate an earlier study showing a possible magnetic alignment response in chicken embryos. Although chicken embryos did show non-random alignment, we were not able to find a magnetic effect. Alignment is also an important feature of animal constructions and is very likely to have fitness consequences, which we explored in woodpecker cavity alignments in a meta-analysis of available global data. The latitudinal and continental pattern in 23 species of woodpeckers suggests that an alignment response can have the proximate function to regulate microclimate in the cavity and therefore, presumably, optimize incubation temperatures and increase hatching success. Overall, the presented findings show how experimental and observational studies of spontaneous alignment behavior can provide insight into the ecology and sensory biology of a wide range of animals. / Ph. D.