Ecology

Most delphinids produce narrowband frequency-modulated whistles with a high level of plasticity to communicate with conspecifics. It is important to understand geographic variation in whistles as signal variation in other taxa has provided insight into the dispersal capabilities, genetic divergence and isolation among groups, and adaptation to ecological conditions. I investigated whistle variation of Indo-Pacific humpback dolphins (Sousa chinensis chinensis), Taiwanese humpback dolphins (S. c. taiwanensis) and Australian humpback dolphins (S. sahulensis) to test whether differences in whistles support the hypotheses of population structure, regional and species differences in the genus Sousa, which were based on morphological and genetic data. I also investigated important factors that may contribute to local distinctiveness in whistles including behavioural state, group size, and the influence of vessel noise. Multivariate analyses of seven acoustic variables supported the hypotheses of population structure, regional and species differences. Acoustic diversification between groups is likely influenced by behaviour and social contexts of whistles, and environmental noise. The use of sound to identify discrete groups of humpback dolphins may be important in future studies where genetic and morphological studies may not reveal recent differentiation or are difficult to conduct.

Author Keywords: Bioacoustics, Cetacean, Geographic variation, Population biology, Sousa, Whistle characteristics

The recent northward expansion of the white-footed mouse (Peromyscus leucopus) in response to climatic changes provides a natural experiment to explore potential adaptive genetic variation within the clock gene Per1 in Peromyscus undergoing latitudinal shifts, as well as, the possibility of hybridization and introgression related to novel secondary contact with its sister species the deer mouse (Peromyscus maniculatus). Because clock genes influence the timing of behaviors critical for survival, variations in genotype may reflect an organism's ability to persist in different environments. Hybridization followed by introgression may increase the adaptive potential of a species by quickly generating adaptive variation through novel genetic recombination or by the transfer of species-specific alleles that have evolved in response to certain environments. In chapter 2, I used microsatellite and mtDNA markers to test for hybridization and introgression between P. maniculatus and P. leucopus and found that interbreeding is occurring at a low frequency (<1%). In chapter 3, I tested for a latitudinal cline in a polyglycine repeat located within the Per1 gene of Peromyscus and discovered a putative cline in the Per1-142 and Per1-157 allele of P. leucopus and P. maniculatus, respectively. Chapter 4, further expands upon these findings, limitations, and the lack of evidence supporting introgression at the Per1 locus. Despite this lack of evidence, it is possible that novel hybridization has or could lead to adaptive introgression of other genes, allowing for the exchange of adaptive alleles or traits that could be advantageous for range expansion and adaption to future environmental changes.

Author Keywords: Clock genes, Hybridization, Latitudinal gradient, Per1, Peromyscus, Range Expansion

Long-term studies of demographic processes such as survival and abundance conducted in unexploited systems provide unique insight into the natural population ecology of fish, but are rarely available. I used historical tagging records of a sanctuary population of brook trout (Salvelinus fontinalis) in Algonquin Park, Ontario to investigate long-term population dynamics in an unexploited population. Adult brook trout in Mykiss Lake (23.5ha) were surveyed and tagged biannually (May and October) between 1990 and 2004. Open-population capture-mark-recapture models were used to test the importance of time, size, sex and season on estimates of apparent survival and abundance. Seasonal population growth and recruitment were estimated and compared with large-scale climate indices. Time-dependent survival and abundance estimates fluctuated, with distinct periods of increase. Population growth and recruitment were positively correlated with summer NAO and ENSO values, whereas survival was negatively correlated. Seasonally, larger individuals experienced higher apparent survival during winter and decreased survival during summer. These findings provide valuable insights into the natural demography of unexploited brook trout populations, and should help inform sustainable management of inland fisheries.

Author Keywords: capture-mark-recapture, long-term, population dynamics, Salvelinus fontinalis, seasonal variation, survival

Stopover ecology is a topic that surges in relevancy as choices made by migrants during stationary periods (stopover sites) may not only have important individuals' fitness consequences but also can affect population dynamics. I used MOTUS automated telemetry array to study fall stopover duration of Blackpoll Warbler (BLPW) and departure decisions of BLPW and Canada Warbler (CAWA) in relation to various predictors. I affixed radio-transmitters on 55 BLPWs and 32 CAWAs at two banding stations in Ontario in September-October 2014-2015. Radio-tagged individuals were tracked through the MOTUS network across southeastern Canada. I developed models relating age class, fat score, Julian date and stopover movement types to Blackpolls' stopover duration. I also examined whether there were species-related differences of wind selectivity when resuming migration. No explanatory variable significantly influenced BLPW's stopover duration. Both species tended to depart under increased tailwind assistance, but with no difference in the effect of wind conditions between the two species. This study provides further evidence supporting the relevance of local wind conditions as a key factor affecting the departure likelihood, especially when migrating birds face an ecological barrier.

Author Keywords: Cardellina canadensis, departure decisions, minimum stopover length, MOTUS, overland fall migration, Setophaga striata

Changes to the Arctic and sub-Arctic climate are becoming increasingly evident as it warms faster than other areas of the globe, supporting evidence that predictions of future warming will be amplified due to positive feedback mechanisms. The Southern Hudson Bay polar bear (Ursus maritimus) subpopulation is one of the most southerly subpopulations in the world, putting it at increased risk due to effects of climate change. Whereas many other subpopulations have been the subject of intense research and monitoring, little research has been completed detailing the movement behaviour and space use of bears within Southern Hudson Bay. I used detailed movement data collected on female polar bears to establish a baseline of movement information for this subpopulation to which future work can be compared and effects of climate change can be assessed I evaluated the use of core areas during critical periods of the year (breeding and ice breakup) and evaluated common space use as a means of assessing site fidelity during the breeding season. Movement rates and home range sizes were comparable to those of the neighbouring Western Hudson Bay subpopulation. I also found evidence of increased occurrences of long distance, late fall movements along the coast to the northwest, presumably to gain earlier access to first ice. Though space use analysis did not reveal evidence of site fidelity to specific breeding areas in Hudson Bay, I found that core use areas are at risk of substantially shortened ice duration (x¯ =76 days shorter) using projected ice data based on the high emissions A2 climate change scenario.

Author Keywords: climate change, Hudson Bay, movement, polar bear, sea ice, utilization distribution

Most grassland bird populations are in decline, so it is becoming increasingly important to understand how they use agricultural field types and form their communities. I performed point counts in cultural meadow, intensive agriculture, and non-intensive agriculture areas in 2011 and 2012. Generalized linear models were used to determine the habitat relationships of six focal species. I found that non-intensive agriculture was used most often and intensive agriculture was often avoided, but there were exceptions which indicate habitat use can be species-specific. I determined in which habitats competition was likely occurring and which species pairs were competing in 2011. In 2012, I experimentally tested these relationships by introducing artificial competitors onto sites. By comparing presence-absence data from 2011 to 2012, I found evidence of habitat-mediated interspecific and conspecific attraction involving Bobolink and Grasshopper Sparrow. This research contributes to the current understanding of grassland bird community ecology and conservation.

Author Keywords: agriculture, BACI, community ecology, habitat use, species at risk, species interactions

In order to effectively manage recreational fisheries, it is important to understand how the resource is being used. In this thesis, long-term creel census data, collected on Lake Opeongo in Algonquin Provincial Park, Ontario, Canada was used to assess fine-scale angler dynamics within a recreational Lake Trout (Salvelinus namaycush) fishery. The spatial distribution of angler reported catch locations of Lake Trout within the lake, was assessed using an Optimized Hotspot Analysis in ArcGIS. Areas of significant clustering of catch locations were revealed during all time periods and varied in size and location both seasonally and temporally. Cormack-Jolly-Seber models were used to evaluate the probability of individual angling boats persisting in the regional fishery and being detected on Lake Opeongo through time, as well as to examine the effect of angler travel distance and gas prices on participation parameters. Time-varying models revealed that the probability of an angler persisting in the fishery varied, while detection estimates remained stable. Travel distance had a negative effect on both parameters while increased gas prices only had a slight negative effect on detection estimates. Additionally, among Lake Opeongo anglers, angling avidity varied as did lake specific fishing experience. Average CUE was found to be higher among angling parties who visited the lake more often than fishing parties who visited relatively few times.

Since its introduction to North America in the 1990s, the Round Goby has spread throughout the Great Lakes, inland through rivers and is now moving into small tributary streams, a new environment for this species in both its native and invaded ranges. I explored density and temporal occupation of Round Gobies in four small streams in two systems in south-central Ontario, Canada in order to determine what habitat variables are the best predictors of goby density. Two streams are tributaries of Lake Ontario and two are tributaries of the Otonabee River, and all of these streams have barriers preventing upstream migration. I found that occupation and density differed between the systems. In the Otonabee River system, Round Gobies occupy the streams year round and the most important factor determining adult density is distance from a barrier to upstream movement, with the entire stream occupied but density highest next to the barriers. In the Lake Ontario system, density is highest at mid-stream and Round Gobies appear to occupy these streams mainly from spring to fall. Adult density in Lake Ontario tributaries is highest in sites with a high percentage of cobble/boulder and low percentage of gravel substrate, while substrate is less important in Otonabee River tributaries. Occupation and density patterns may differ due to contrasting environmental conditions in the source environments and distance to the first barrier preventing upstream movement. This study shows diversity in invasion strategies, and provides insight into the occurrence and movement patterns of this species in small, tributary streams.

Author Keywords: biological invasion, Generalised Additive Mixed Model, habitat, Neogobius melanostomus, Round Goby, stream

The purpose of this thesis is to quantify the habitat characteristics, density patterns and environmental niches of two groups of Indo-Pacific humpback dolphins: Chinese white dolphins (CWD) of the Pearl River estuary (PRE), and Taiwanese white dolphins (TWD, =Taiwanese humpback dolphin, THD) found in the eastern Taiwan Strait (ETS). Much work has already been done on the habitat use of CWDs in parts of the PRE, so the purpose of my first two chapters was to advance knowledge of the TWD to a comparable level. Chapter 2 contains the first published description of the relatively shallow, inshore, estuarine habitat of the TWD. General environmental characteristics and observed group sizes were consistent with other populations of humpback dolphins, and group sizes were not correlated with the environmental variables measured during surveys. Chapter 3 investigated density patterns of TWDs, finding spatiotemporal heterogeneity across the study area. Humpback dolphin densities fluctuated from year to year, but some parts of the study area were consistently used more than others. Environmental characteristics again did not influence dolphin densities, though more dolphins than expected were sighted in waters adjacent to major land reclamations, which may be related to the location of these areas close to major rivers. In Chapter 4, niches of the TWD and CWDs found in the PRE were compared using species distribution models, which indicated significant niche overlap. This may be due to niche conservatism maintaining similar fundamental niches between the two groups since their historical split >10,000 years ago, or a result of the intrinsic biotic factors that influence occurrence data affecting the hypervolume dimensions of each realized niche in similar ways. Geographic predictions indicate that most of the TWD's range has likely been surveyed, and that there may be connectivity between PRE humpback dolphins and at least one neighbouring putative population due to continuous predicted suitable habitat in waters that remain poorly surveyed. Overall, my thesis demonstrates that density patterns may vary over time, but on a broad temporal scale, these two allopatric groups of Indo-Pacific humpback dolphins have similar habitat requirements in geographically isolated, but environmentally similar locations.

Author Keywords: density, habitat, Indo-Pacific humpback dolphin, niche overlap, Sousa chinensis, species distribution model

The KWIC Speakers Bureau is a database of local speakers who have volunteered to share their personal knowledge and experiences with the community - as public speakers, discussion leaders, lecturers, and in many other capacities. This year KWIC's focus is on environmental issues, and the expertise that members of the Peterborough community possess in this area is reflected in the wide variety of issues and subject matters that can be found in the Speakers Bureau. This project includes a User's Manual of how to use the database, an article for KWIC's fall newsletter describing the project and it's benefits to the community, as well as a personal reflection, which focuses on the development and implementation of the project.