Throughout midwestern North American ecosystems, semi-aquatic mammals including beaver (Castor canadensis), mink (Neovision vision), muskrat (Ondatra zibethicus), and river otter (Lontra canadensis) co-exist in wetlands. These species are ecologically important through their manipulation of habitats and interactions with other species present. The Lake County Forest Preserve District (Lake County, Illinois) is actively restoring forest preserves using several restoration practices and are interested in how these efforts may affect semi-aquatic mammal occupancy. We studied impacts of restoration practices and other environmental covariates on detection and occupancy of the 4 aforementioned focal species. Sign surveys were conducted during December-April in 2018-19 and 2019-20. Single species, multi-season models were run in RStudio using the package unmarked. Muskrat detection (p̂ = 0.60 ± 0.03) was positively affected by survey replicate, and negatively impacted by last precipitation amount and bank angle. Beaver detection (p̂ = 0.76 ± 0.03) was positively affected by survey replicate and previous 2-week precipitation amount, and negatively influenced by bank angle. Mink detection (p̂ = 0.26 ± 0.04) was positively impacted by survey replicate, and negatively affected by last precipitation amount and previous 2-week precipitation amount. River otter detection (p̂ = 0.10 ± 0.07) was not influenced by any covariates sampled. Muskrat had the highest occupancy (ψ ̂= 0.90 ± 0.05), followed by beaver (ψ ̂ = 0.57 ± 0.07), mink (ψ ̂ = 0.57 ± 0.10), and river otter (ψ ̂ = 0.28 ± 0.18). Both muskrat and river otter occupancy were not affected by any covariates sampled. Beaver occupancy was positively impacted by stream density and number of saplings. Mink occupancy was positively affected by stream density. No focal species’ occupancies were influenced by restoration practices. From these findings, I provide recommendations for future surveys and management for semi-aquatic furbearers in urban landscapes. Thank you to the Lake County Forest Preserve District for funding my research.

Mammals in freshwater aquatic systems play important roles as ecosystem engineers, trophic transfer agents, and apex predators, thus acting as indicators of freshwater ecosystem function. Watersheds inhabited by semi-aquatic mammals have increased links between adjacent terrestrial and aquatic ecosystems compared to watersheds where they are not present. Semi-aquatic mammals not only exert top-down influences on streams, but are affected by bottom-up forces from the riparian system itself. The goal of this study was to identify variables that correlate with the presence of beaver (Castor canadensis), muskrat (Ondatra zibethicus), mink (Neovison vison), and river otter (Lontra canadensis), including their interactions, resulting in a better understanding of the areas where these semi-aquatic mammals occur and their effects on the riparian system. The objectives of this study were (1) to identify variables related to the probability of detection, initial occupancy, colonization, and extinction of the 4 semi-aquatic mammals in southern Illinois; and (2) to test if the reintroduction of river otter has changed stream food webs. To address my first objective, I sampled 120 bridge sites in 2 periods (winter: Jan-Feb; and spring: Mar-Apr) during 2012–2014 in 11 major watersheds in the southern third of Illinois (44,526 km2) to estimate multi-season occupancy. Each survey unit was a 400-m stream segment visited twice by 2 observers for a total of 4 observations per site per period. Observers recorded all mammal signs found, including sign species and type. Sites were Intensive Basin Survey Sites sampled by Illinois Department of Natural Resources (IDNR) and Illinois Environmental Protection Agency (IEPA), allowing data collected by the state to be available for explanatory variables for mammal occupancy. Data collected by the Illinois Natural History Survey (INHS) also were available for a subset of sites. I collected local- and landscape-scale habitat and weather variables for each site. I developed hypotheses regarding occupancy of sites based on land-cover, human disturbance, and stream attributes for each species. I developed additional hypotheses regarding prey availability and water quality for river otter and mink. Sites used in each analysis were dependent on data available to address the hypotheses of interest. Beaver and muskrat were present at ≥100 of 103 sites for ≥1 observation. Naïve occupancy was high (≥82%) every year for both species. Detection probabilities for beaver and muskrat were best predicted by survey period. Beaver detection remained fairly constant across survey periods except for a decrease in winter 2014, whereas muskrat detection was generally lower during winter and higher during spring. Beaver were more likely to occupy larger streams than smaller streams during the initial survey period. Sites that lacked a dominant land-cover had a lower probability of beaver colonization than sites dominated by agriculture or woody vegetation at the landscape scale. In addition, the probability that a site would be colonized by beaver during the study increased with availability of water within 1 km of the surveyed segment, increased stream density, sites at larger streams, and river otter presence during the previous period. The probability of site extinction decreased as stream size, stream density within 1 km, and water availability within 500 m of the survey segment increased. Occupancy of muskrat during the initial survey period was negatively predicted by % forest in the 1-km riparian area, channel incision, and amount mercury in the sediment. Colonization by muskrats was lower during the long spring to winter intervals than the short winter to spring intervals, and was positively related to the amount of organic carbon in the sediment. The probability of site extinction by muskrat increased with increasing % forest within the riparian area around the stream segment, decreasing 1-km stream density, and when land-cover within 1 km of sites was dominated by agriculture or woody vegetation. Multi-season occupancy of river otter and mink were assessed in 2 separate analyses that used either land-cover and management variables or prey availability and riparian community composition, respectively. In the first analysis, river otter and mink were present at ≥84 of 103 sites. Naïve occupancy was higher every year for mink (≥88.3%) than for river otter (≥55.3%). Detection of river otter and mink in the first analysis increased as substrate availability increased. Occupancy of river otter during the initial survey period was predicted by large stream size, low % developed area within 250 m of the surveyed segment, and proximity to nearest river otter reintroduction point. Probability of colonization by river otter varied by survey period and was higher at sites with larger streams, higher stream density, lower % developed area, and within a known river otter population area. Site extinction by river otter in the first analysis varied by survey period and was linked to increased organic carbon in the sediment, and decreased road density within 1 km of the surveyed segment. River otter harvest was not found to affect site colonization or extinction. Mink occupancy during the initial period was negatively associated with water availability within 100 m of the survey segment. Site colonization by mink varied by month and increased with increasing developed area within 100 m of the surveyed segment, increasing channel incision, and decreasing rainfall. Probability of site extinction for mink increased as stream size and developed area within 500 m of the surveyed segment increased, and when woody vegetation was the dominant land-cover type within 1 km of the surveyed segment. The second analysis of multi-season occupancy of river otter and mink used 77 sites, 81.8% of which had ≥1 river otter detection in the study and 98.7% of which had ≥1 mink detection. Naïve occupancy differed between years but gradually increased for river otter and remained high (≥93.5%) for mink. Increasing substrate availability increased the probability of river otter detection, whereas mink detection varied by survey period. Occupancy during the initial survey period was higher in sites closer to the reintroduction points for river otter. Probability of colonization of river otter was positively associated with macroinvertebrate IBI and fish species richness, sites with high fish species richness of fish families preferred by river otter also had reduced otter extinction probability. No tested variables predicted initial occupancy for mink, but mink were more likely to colonize sites with increased fish richness and when muskrat were present during the previous period. Mink had decreased probability of extinction in sites with increasing mussel community index. My results indicate that semi-aquatic mammals in Illinois were affected by a riparian habitat, water availability, and stream community variables at both the landscape and local scale. I found high occupancy of mink, beaver, and muskrat across the entire landscape of southern Illinois, and my results suggest that the geographic range of river otter continues to expand. Relationships of occupancy of these semi-aquatic mammals to measurements of urban areas and human disturbance were not consistent across all species. Mink and river otter occupancy were both predicted by aspects of prey availability, indicating the importance of predator-prey relationships in occupancy dynamics of riparian predators. Hypotheses regarding predator pressure and changes in environmental variables were used to test the effects of river otter reintroduction on stream communities. For this objective, I used structural equation models. I compared fish and macroinvertebrate communities from before (1982-1995) and after (2005-2013) reintroduction of river otter, which occurred in 1994–1996. Fish and macroinvertebrate community data for 35 sites located throughout 6 major watersheds in southern Illinois (25,550 km2) were obtained from state agencies. Changes in stream communities were evaluated using 4 metrics (species richness, species dominance, skewness in size distribution of prey, and proportion of individuals in the size class preferred by river otter). Neither the inclusion of river otter site use nor change in stream quality, measured by change in % forest, improved models over the simple model which only included fish and macroinvertebrate communities. Overall, I found no evidence that river otter presence or change in forest cover affected stream fish and macroinvertebrate communities.

Among vertebrates, whole-body movement is centered around the vertebral column. The bony vertebral column primarily consists of trabecular (spongy) bone that adapts in vivo to support mechanical demands respective to region, ontogeny, ecology, and locomotion. Previous work has extensively investigated the formfunction relationships of vertebral trabecular bone in terrestrial mammals, who use limb contact with a substrate as the primary support against gravity. However, we lack data from obligate swimming mammals whose locomotor ecology diverged from their terrestrial counterparts in two major ways: (1) body mass is supported by water’s uplifting buoyant forces and (2) swimmers power movement through dorsoventral loading of the axial body. This study examined vertebral trabecular bone mechanical properties and micoarchitecture from fully aquatic mammals, specifically sirenians (i.e. manatees) and cetaceans (i.e. dolphins and whales). We compression tested bone from several regions of the vertebral column among developmental stages in Florida manatees (Trichechus manatus latirostris) and among 10 cetacean species (Families Delphinidae and Kogiidae) with various swimming modes and diving behaviors. In addition, we microCT scanned a subset of cetacean vertebrae before subjecting them to mechanical tests. We demonstrated that in precocial manatee calves, vertebrae were the strongest and toughest in the posterior vertebral column, which may support rostrocaudal force propagation and increasing bending amplitudes towards the tail tip during undulatory swimming. Among cetaceans, we showed that greatest strength, stiffness, toughness, bone volume fraction, and degree of anisotropy were in rigidtorso shallow-divers, while properties had the smallest values in flexible-torso deep-divers. We propose that animals swimming in shallower waters actively swim more than species that conduct habitual glides during deep descents in the water column, and place comparatively greater loads on their vertebral columns. We found that cetacean bone volume fraction was the best predictor for mechanical properties. Due to the shared non-weight bearing conditions of water and microgravity, we present these data as a contribution to the body of work investigating bone adaptations in mammals that live in weightless conditions throughout life and evolutionary history. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-05T13:59:07Z No. of bitstreams: 2 TESE Fábia de Oliveira Luna.pdf: 6070926 bytes, checksum: 5c0233b17f6af6c3a2f420f1d6eb3248 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-05T13:59:07Z (GMT). No. of bitstreams: 2 TESE Fábia de Oliveira Luna.pdf: 6070926 bytes, checksum: 5c0233b17f6af6c3a2f420f1d6eb3248 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / The West Indian manatee (Trichechus manatus) and the Amazonian manatee (Trichechus inunguis) belong to the mammalian Order Sirenia, classified respectively as critically endangered and as vulnerable in Brazil. Both species have been hunted commercially since the sixteenth century, resulting in a drastic reduction or elimination of manatees in some places. This hunting pressure may have caused isolation of the populations resulting in geographic genetic isolation, with a reduction of their genetic diversity. The objective of this study is to understand the genetic diversity and population structure of the West Indian manatee (T. manatus) in Brazil; verify the existence of hybridization between the manatees T. manatus and T. inungus; define the degree of relatedness of individuals in captivity; and provide strategies for the conservation of the species. In northeastern Brazil, a large number of dependent calves strand on beaches. Many of these calves have been rescued alive and rehabilitated for future release. Previously, the identification of release sites did not take into account the genetic issues. Through this study, it has been possible to identify suitable release sites based on phylogenetic traits of the manatees. The genetic structure of the population was studied using nuclear DNA in the program STRUCTURE, and comparing FST and RST values. On the Northeast coast one population was identified, which is subdivided in two subpopulations. A different genetic population was found in the Northwest of the Amazon River estuary (extreme north of Brazil, Guyana and Venezuelan). Manatees from the Estuary of the Amazon River grouped with Amazonian manatees from the Santarém region to form a third population. A total of four manatee Management Units were identified along the Brazilian coast, which should be treated separately for management and conservation needs. Using a combination of molecular markers (mtDNA and nDNA) and cytogenetic analyses the existence of hybridization between T. manatus and T inunguis was confirmed, although this does not appear to be a frequent occurrence. Some of the dependent calves rescued, and other individuals transferred from irregular captive conditions to the CMA/ICMBio, were kept together and breeding occurred. Maintaining related manatees together can lead to inbreeding. It was possible 29 to establish the degree of relatedness between individuals kept at CMA/ICMBio and verify the extistence of inbreeding. To avoid inbreeding, hybridization, and overpopulation in captivity, it is necessary that males and females be separated immediately, thereby preventing reproduction ex-situ. The present study allows us to establish actions for the conservation of the West Indian manatee. Actions that should be prioritized include: protection and restoration of habitat with the creation and implementation of specific protected areas; creation and maintenance of travel corridors that allow gene flow; reduction and elimination of anthropogenic pressures on the species; stopping pointless reproduction in captivity; designing further studies in the north of Brazil to better understand the hybridization and implement the action plan.

Two sympatric dolphin species, Stenella frontalis and Tursiops truncatus, resident to Little Bahama Bank, Bahamas were found to mostly forage independent of one another, but occasionally foraged in mixed groups. Analysis of over 20 years of data revealed the degree of overlap to be minimal with spatially distinct regions identified for both species, environmental segregation based on depth, bottom type, temperature, and time of day. Results based on observational data indicated significant differences in group size and selected prey. For S. frontalis, lactating females had the most distinct diet, which differed from that of non-reproductively active (NRA) females. Pregnant females had ambiguous prey use results, but diet differences were revealed through nutritional analysis. Lactating females had a higher intake of all nutrients (% moisture, % lipid, % protein, and calories) than pregnant females but lower than NRA females. Mother and calf pairs selected prey for caloric and moisture values. The influence of calves on foraging groups was reflected through discrete differences in all nutrients. Males and females appeared to select the same major prey, but female prey use was much more diverse. / by Christopher R. Malinowski. / Thesis (M.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

Atlantic spotted dolphins (Stenella frontalis) and bottlenose dolphins (Tursiops truncatus) are two sympatric species resident to the Bahamas. The visibility of the Bahamian water provided a unique opportunity to study spotted dolphin communication during aggression. This study’s main focus was to decipher any similarities or differences in the behaviors used by spotted dolphins during interspecific and intraspecific aggression. Both similarities and differences were discovered. Biting, following, and chasing behavioral events were used more during interspecific aggression, while the display behavioral class was used more than the contact behavioral class during intrabut not interspecific aggression. This study showed that spotted dolphins use more energy intensive and risky behaviors when fighting interspecifically. This could result from having to fight and defend females from a larger species, trying to avoid sexual harassment from bottlenose males, or needing to use behaviors that are more overt and easily understood during interspecies communication. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection