The Influence of the River Otter (Lontra Canadensis) on Aquatic Conservation in the Greater Yellowstone Ecosystem PDF Download
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Author: Kelly Jo Pearce
Publisher:
ISBN:
Category : Conservation biology
Languages : en
Pages : 130
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Book Description
Large scale habitat loss, unprecedented rates of species extinction, and other biodiversity issues have prompted wildlife conservationists to increasingly apply the ?flagship? species concept to guide conservation decision making. Flagships are designated based on their ability to serve a socio-economic role, attracting public attention and financial support to conservation initiatives. Critical to flagships success is selecting an appropriate flagship?one that will be widely supported and will not invoke ill-will among any stakeholders. Thus, determining if the species meets certain pre-established criteria that are known to influence social-psychological processes is a critical step in flagship selection. The river otter (Lontra canadensis) is a widely distributed apex predator and possesses various other socio-ecological traits that make it suitable for a flagship species. However, empirical evidence supporting the use of the river otter as a flagship is lacking. In this dissertation, I study the ability of the river otter to serve as a flagship species in the Greater Yellowstone Ecosystem, one of the largest intact temperate-zone ecosystems in the world. I examine visitor attitudes and perceived resource conflicts with river otters and anglers, assess visitor willingness to engage in pro-conservation behaviors to help river otter conservation, and estimate probability of viewing the river otter using camera-traps along the Snake River. In addition to fulfilling certain recommended criteria of a flagship species, such as having a large body size, being charismatic, encompassing a wide-spread geographic range, and being uncommon across the landscape, my results suggest that visitors and anglers have positive attitudes towards the river otter, and that exposure to the river otter increases people?s willingness to engage in pro-conservation behaviors to help conserve the river otter and its aquatic habitat. However, pre-existing negative media portrayals as well as low visibility of the species, are potential liabilities of the river otter as a conservation flagship. The studies in this dissertation deepen the understanding of river otter socio-ecology as well as develop and apply elements of a socio-ecological framework that refine the approach of effectively selecting a successful conservation flagship.
Author: Kelly Jo Pearce
Publisher:
ISBN:
Category : Conservation biology
Languages : en
Pages : 130
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Book Description
Large scale habitat loss, unprecedented rates of species extinction, and other biodiversity issues have prompted wildlife conservationists to increasingly apply the ?flagship? species concept to guide conservation decision making. Flagships are designated based on their ability to serve a socio-economic role, attracting public attention and financial support to conservation initiatives. Critical to flagships success is selecting an appropriate flagship?one that will be widely supported and will not invoke ill-will among any stakeholders. Thus, determining if the species meets certain pre-established criteria that are known to influence social-psychological processes is a critical step in flagship selection. The river otter (Lontra canadensis) is a widely distributed apex predator and possesses various other socio-ecological traits that make it suitable for a flagship species. However, empirical evidence supporting the use of the river otter as a flagship is lacking. In this dissertation, I study the ability of the river otter to serve as a flagship species in the Greater Yellowstone Ecosystem, one of the largest intact temperate-zone ecosystems in the world. I examine visitor attitudes and perceived resource conflicts with river otters and anglers, assess visitor willingness to engage in pro-conservation behaviors to help river otter conservation, and estimate probability of viewing the river otter using camera-traps along the Snake River. In addition to fulfilling certain recommended criteria of a flagship species, such as having a large body size, being charismatic, encompassing a wide-spread geographic range, and being uncommon across the landscape, my results suggest that visitors and anglers have positive attitudes towards the river otter, and that exposure to the river otter increases people?s willingness to engage in pro-conservation behaviors to help conserve the river otter and its aquatic habitat. However, pre-existing negative media portrayals as well as low visibility of the species, are potential liabilities of the river otter as a conservation flagship. The studies in this dissertation deepen the understanding of river otter socio-ecology as well as develop and apply elements of a socio-ecological framework that refine the approach of effectively selecting a successful conservation flagship.
Author: Jamie R. Crait
Publisher:
ISBN: 9781303106767
Category : Otters
Languages : en
Pages : 178
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River otters (Lontra canadensis) in Yellowstone Lake, Yellowstone National Park, depend on native cutthroat trout (Oncorhynchus clarki bouvieri) as prey, especially during summer when the fish migrate from the lake into its tributary streams to spawn. As part of their social behavior, otters deposit excreta at latrine (scent-marking) sites along these spawning streams and fertilize riparian plants with aquatically-derived nutrients such as nitrogen (N). Over the last two decades, however, nonnative lake trout trout (Salvelinus namaycush ) and whirling disease (caused by the parasite Myxobolus cerebralis), have contributed to a dramatic decline in the lake's cutthroat trout population. Declines in cutthroat trout could reduce the abundance and distribution of otters, and sever the nutrient link they provide. This dissertation describes aspects of the biology of river otters in Yellowstone Lake in the context of these changes to the lake's food web. This dissertation is presented in four journal-formatted chapters. Chapter 1 compares the hematology of high elevation Yellowstone otters with a sea level population. Comparisons of oxygen dissociation curves revealed no significant difference in hemoglobin-oxygen binding affinity between the two populations. Instead, high elevation otters had greater hemoglobin concentrations than their sea level conspecifics. Yellowstone otters displayed higher levels of the vasodilator nitric oxide, and half the concentration of the serum protein albumin, possibly to compensate for increased blood viscosity. Theoretical aerobic dive limits were similar between high elevation and sea level otters due to the lower availability of oxygen at altitude. Chapter 2 presents the first estimates of population size and survival for river otters in Yellowstone National Park. Although the cutthroat trout population continued to decline during the study, there was no significant change in otter population size. However, overall densities (1 otter/9.91 km of shoreline) were lower than reported for most river otter populations, and evidence of a recent genetic bottleneck suggested the population may have already declined by the onset of the study. Annual survival for otters was 0.67 and correlated with cutthroat trout abundance in some models. Otters primarily responded to reductions in cutthroat trout via behavioral shifts in their spatial distribution and prey consumption. Activity at latrine sites decreased with declines in cutthroat trout on several tributary streams. Cutthroat trout remained the dominant prey item in otter scats throughout the study, but showed a declining trend from a frequency of occurrence of 73% in 2003 to 54% in 2008. Chapter 3 documents the effects of otter-derived N fertilization on trees at latrine sites. Stable N isotope (15 N) values were higher in needles of Engelmann spruce (Picea engelmannii) and lodgepole pine (Pinus contorta) on otter latrines than at reference sites. However, tree growth was greater on reference sites. No relationship existed between cutthroat trout abundance and tree ring 15 N, precluding the ability to detect whether the trout-otter-excreta link has changed with the cutthroat trout population. Chapter 4 is a note on seasonal breeding in Yellowstone otters. Although river otters in temperate regions typically breed in March and April, Yellowstone otters showed evidence of late seasonal breeding in June. This observation suggests otters in Yellowstone Lake have a relatively long breeding season, or their breeding schedule is delayed so that energetically-demanding lactation coincides with spawning runs of Yellowstone cutthroat trout. (Abstract shortened by UMI.)
Author: Danaan DeNeve Weeks
Publisher:
ISBN:
Category :
Languages : en
Pages : 226
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The North American river otter is a semiaquatic carnivore that occupies freshwater habitats across most of North America, and is a conservation symbol across most of its range. It is used as an indicator species, a keystone species, an umbrella species, and an example of conservation success. The broad distribution of river otters suggests a broad range of habitat tolerances, but they appear to be highly sensitive to anthropogenic habitat alterations. This apparently conflicting robustness across habitat types and sensitivity to habitat change has baffled researchers for decades. Using morphometric, modeling, and synthetic approaches I explored how otters relate to their environment on a broad scale to gain a better understanding of the conditions to which they are robust, the conditions to which they are sensitive, and the mechanisms by which they adapt to varying environments. Using Maximum Entropy species distribution models I determined that river otter distributions are not strongly affected by climate or macro-environmental variables. Using geometric morphometric methods to examine how cranial shape varies across geographic and ecological space, I determined that morphological variation which may affect feeding and locomotion occurs more intensely at local than broad scales, indicating local morphological adaptation is not strong in this species. Finally, a review of the phylogeography and ecology of river otters and related species indicated that this species evolved from a low-speciation lineage that tends to produce species that can occupy a wide variety of environments without undergoing evolutionary change. Overall I determined that river otters do indeed have a broad ecological niche, and do not respond strongly to climatic or environmental differences or changes across their habitats through altering their distributions or locally adapting. Evidence suggests that river otters may respond strongly to anthropogenic alterations of their habitats because anthropogenically-induced habitat alterations tend to have strong consequences for aquatic food chains, and otters may be more reliant on robust food webs than they are on other aspects of their habitats. These findings have implications for how we think of otter conservation and the conservation of species and ecosystems that are strongly affected by otter presence, as well as what otters indicate about their habitat quality. Additionally, these results may shed light on the ecologies of other mustelid carnivores. In the first chapter of my dissertation I conducted a review of the phylogenetics and biogeography of North and South American river otters to investigate how geography and environmental change have driven river otter evolution in the Americas, and how this informs the ecology of the modern species. I focused first on reviewing the biogeography and evolutionary history of Lontra and Pteronura, and then on the modern ecology, threats, and conservations status of each of the four modern species of Lontra and the single extant species of Pteronura. I chose to review these species because they overlap in geographic and environmental space, and because their shared history provides means for an evolutionarily-grounded examination of relative rarity, specialization, and level of conservation concern. I found that speciation between American otters primarily occurs allopatrically, and there is little functional differentiation in response to allopatric speciation, though they do appear to have the ability to adapt in response to extreme conditions when necessary. Additionally, allopatric speciation primarily occurs in response to changes in waterway connectivity, which is also responsible for changes in population connectivity within the modern species. Most otters have less specific habitat requirements than previously thought, as all species of Lontra persist across a wide variety of climates and semi-aquatic environments, and most of them do so without exhibiting a strong evolutionary response. All American river otters exhibit a strong sensitivity to anthropogenic habitat destruction, though several of them have also shown some ability to coexist with humans. Evidence from this study provides strong indication that this has to do with how human activities near waterways affect food webs, and more generally that on closer examination many habitat components previously thought to be requirements for otters may be better interpreted as indicators of food availability. In the second chapter of my dissertation I use species distribution modeling to examine river otter associations with climate and environment across their range to explore their apparently conflicting robustness to habitat change and sensitivity to human presence. Specifically, I examined the climate and landcover variables that constrain the geographic distribution of otters. I obtained otter occurrences from GBIF and BISON biodiversity databases, climate variables from BIOCLIM, and environmental layers from NASA's SEDAC program. I built Maximum Entropy species distribution models at 80 and 150 km spatial thinning and varying numbers of background points. The combined model at 80 km spatial thinning and default number of background points produced the highest quality models. Six climatic and landcover variables explained over 10% of otter distributions each: open shrubland, net primary productivity, urban/built, water, annual mean temperature, and precipitation of coldest quarter. Of these variables I determined that water, annual mean temperature, and precipitation of coldest quarter likely have biological significance. However, the predicted range map generated by these models do not match river otter distributions generated by the IUCN and NatureServe. This is likely due to incomplete occurrence data because of low reporting in parts of the species range. I conclude based on these data that river otters have broad climatic and habitat tolerances (as there are six weakly predictive variables as opposed to 1-2 strongly controlling variables) and that local habitat factors, such as intact-ness of riverine food webs, may have greater impact on otter distributions than broad regional variables. Additionally, I call for improved monitoring and reporting of this and other broadly-distributed species to ensure we can adequately track their habitat requirements and conservation status. In the third chapter of my dissertation I use geometric morphometrics to explore the role of cranial morphological variation in otter persistence across the array of otter habitats. I address two research questions: 1. Is there morphological variation and structure in river otters across subspecies? 2. Is morphological variation in river otters best explained by a pattern of isolation by distance or isolation by ecology? I obtained 100 river otter crania from across the species range from museums. I 3-D scanned them using a Geomagic 3-D scanner and landmarked them using the IDAV Landmark program. To answer Q1 I conducted discriminant function analyses Procrustes ANOVAs and a Principal Components Analysis. None of these tests revealed strong morphological patterning, indicating there is not morphological differentiation across subspecies in cranial shape. T address Q2 I conducted Mantel tests and a Multiple Matrix Regression with Randomization (MMRR) on the relationship between morphological distance and geographic, climatic, and environmental distance. Both the Mantel test and the MMRR results indicated no significant relationship between morphological distance and climatic or environmental distance in otter crania. Both indicated a weak but negative relationship between morphological distance and geographic distance, indicating morphological variation is greater at short geographic distances and lower at broad geographic distances. I conclude that there is significant cranial variation between individuals, but little definable structure in this variation. The weak but significant (and potentially complex) relationship between geographic and morphological distance indicates the possibility that diversifying selection across smaller spatial scales may be more important than differentiation across broader populations, possibly indicating individual specialization within a generalist population.
Author: Jamie R. Crait
Publisher:
ISBN:
Category : Cutthroat trout
Languages : en
Pages : 10
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Nonnative species threaten ecosystems throughout the world ? including protected reserves. In Yellowstone National Park, river otters Lontra canadensis depend on native cutthroat trout as prey. However, nonnative lake trout and whirling disease have significantly reduced the abundance of these native fish in the park's largest body of water, Yellowstone Lake. We studied the demographic and behavioral responses of otters to declining cutthroat trout on Yellowstone Lake and its tributaries. From 2002-2008, we monitored otter activity at latrine (scent-marking) sites, collected scat for prey identification, and used individual genotypes from scat and hair samples to evaluate survival and abundance with capture?recapture methods. Otter activity at latrines decreased with declines in cutthroat trout, and the prevalence of these fish in otter scat declined from 73% to 53%. Cutthroat trout numbers were the best predictor of temporal variation in apparent survival, and mean annual survival for otters was low (0.72). The density of otters in our study area (1 otter per 13.4 km of shoreline) was also low, and evidence of a recent genetic bottleneck suggests that otter abundance might have declined prior to our study. River otters in and around Yellowstone Lake appear to be responding to reductions in cutthroat trout via changes in distribution, diet, and possibly survival and abundance. Our results provide a baseline estimate for monitoring the broader outcome of management efforts to conserve native cutthroat trout and emphasize the indirect ecosystem consequences of invasive species.
Author: William Ralph Wengeler
Publisher:
ISBN:
Category : Cutthroat trout
Languages : en
Pages : 10
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The introduction of lake trout (Salvelinus namaycush) to Yellowstone Lake in Yellowstone National Park has contributed to a significant decline in the endangered Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri), leading to concern over the persistence of this subspecies but also to piscivorous predators in this community. We assessed the impact of lake trout on a key piscivore, the river otter (Lontra canadensis) in two lakes in Yellowstone National Park. Yellowstone Lake continues to support a native cutthroat trout population, although the recent introduction of lake trout has dramatically impacted the cutthroat trout population. Nearby Lewis Lake has an entirely introduced fish fauna of lake trout, brown trout (Salmo trutta), and Utah chub (Gilia atraria) but lacks cutthroat trout. Analysis of otter scat from Yellowstone Lake implicated trout (lake or cutthroat trout) as a major prey item (57% of scat), whereas stable isotopes identified longnose suckers (Catostomus catostomus) as the primary prey there (58% of diet). By contrast, scat from Lewis Lake implicated minnows, presumably Utah chub, as the primary prey for otters occupying that lake (86%), while stable isotopes implicated brown trout (64%) over both lake trout and Utah chub (36% combined). Our data establish the importance of alternative prey to otters and suggest that lake trout-induced reductions in cutthroat trout may not be catastrophic for otter populations here. These data do not necessarily exonerate lake trout, as their impact on other species, most notably grizzly bears (Ursus arctos) and piscivorous birds, has been documented to be substantial, and further data on the nutritional value of alternate prey are required to confirm or refute a working hypothesis that otter populations will continue to thrive in the face of the lake trout invasion.
Author: Deborah Dorothy Boege-Tobin
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 139
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I studied the spacing patterns and habitat utilization by reintroduced northern river otters, Lontra canadensis, at two sites in Missouri because previous studies of otters indicate, plasticity of a species social structure will likely be due to the tactics employed in acquiring resources in any given area. Seven hypotheses were tested by employing radio-tracking, habitat assessment and geographic information system approaches: (1) home range (HR) and core area (CA) size differ by sex; (2) HR and CA size differ in breeding vs. non-breeding seasons; (3) percent range overlap differs by sex; (4) habitat utilization, as indicated by latrine use, differs seasonally; (5) primary prey type(s) found in scat differ seasonally; (6) environmental characteristics of areas used extensively by otters (latrines, dens, haul-outs) differ from adjacent, unused sites; and (7) stream-order effects and features associated with core area use are similar between two disjointed field sites, and can thus be used along with GIS-driven identifiers to generate predictions regarding suitable habitat for Midwestern river otter populations. Evidence is presented on differences in ranging patterns of otters by location, sex, and seasonality, as well as differences in core area use and accompanying habitat characteristics for the two populations. The following hypotheses were corroborated: (1) male otters had larger HRs and CAs than female otters; (2) female otters maintained small, non-overlapping home ranges; (3) males exhibit a greater percentage of inter- and intra-sexual HR and CA overlap than females; and (4) HR and CA size, and percent overlap differ between a large, riverine ecosystem and a small, meandering stream ecosystem. However, hypotheses examining temporal use of space by otters were not supported. In conclusion, this study suggested that northern river otters exhibit a variety of spacing patterns in different parts of their range, similar to those discovered in other solitary carnivores. Seasonal use of space was different from that typically found in solitary carnivores; differences may be related to habitat characteristics associated with stream order and wetland ecosystems. Overall, although introduced otters came from disjointed regions differing in habitat features and ecological pressures, reintroduced otters have done very well in Missouri.
Author: Daniel Guertin
Publisher:
ISBN:
Category : Ecosystem health
Languages : en
Pages : 0
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North American river otters (Lontra canadensis) are useful indicators of aquatic ecosystem health, but obtaining information on populations is difficult and expensive. By combining non-invasive faecal sampling with DNA genotyping techniques, I investigated: (i) environmental contaminant exposure, (ii) diet, and (iii) population metrics of river otters along the urban coast of southern Vancouver Island, British Columbia, Canada. In Victoria Harbour, mean faecal concentrations of polychlorinated biphenyls (PCBs) exceeded criteria thought to inhibit otter reproduction. However, individual faecal PCB concentrations varied with otter movement and landscape use. Intertidal fish dominated the diet, but otters in the regional harbours consumed proportionally more upper trophic-level fish than otters outside the harbours. Genetic and demographic analyses provided no conclusive evidence of PCB-induced population-level effects. Concurrent monitoring of contaminant exposure and population metrics of river otters is important to detect effects of pollutants on populations, and to guide river otter conservation and ecosystem management.
Author: Shannon Michael Crowley
Publisher:
ISBN:
Category : Otters
Languages : en
Pages : 0
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I investigated patterns in river otter (Lontra canadensis) diet, habitat selection, and behavior at latrine sites in central British Columbia during the ice-free season in 2007 and 2008. I used an Information Theoretic Model Comparison approach to investigate the relationships among otter diet and temporal/spatial parameters and habitat characteristics and the presence, consistency, and intensity of otter activity. Data were collected every two weeks at latrine sites visited by otters. I used a combination of scat content and stable-isotope analysis to investigate the contributions of different prey items to otter diet. Binary and count models were used to predict the presence of individual prey items and number of scats, respectively. A combination of fish spawning period, water body type, and individual lake best described the presence of salmonids, minnows, and insects in otter scat. The relative effects of season and water body varied considerably among the three prey groups found in scats. Scat deposition was positively influenced by a time period when no fish were spawning (early July) and to the kokanee (Oncorhynchus nerka) spawning period (early September). In general, the stable-isotope analysis agreed with the results of the scat content analysis showing a dominance of fish in the diet of otter and a small contribution from other prey sources. The stable-isotope analysis, however, suggested a larger contribution from sockeye salmon and birds relative to data from the scat content analysis. I followed the diet analyses with an investigation of factors that influenced the selection of latrine sites and activity of otter at multiple spatial and behavioural scales. For fine-scale analyses, I performed field measurements at latrine sites and spatially adjacent random sites. At the course landscape scale, I used Geographic Information Systems (GIS) to examine environmental variables that described the broader Tezzeron and Pinchi lake study area. Working at these two spatial scales, I used binary models to predict the presence and consistency (high vs. low use) of latrine sites, and count models to predict the intensity (e.g., number of scat) of latrine site use. Relative to the coarse-scale analysis, I found that habitat characteristics at the fine scale were better at predicting latrine sites. In general, fine-scale selection was influenced by parameters that described visual obscurity, larger trees, and characteristics of conifer trees. The presence of latrine sites at the coarse scale was not accurately described by any of the variables I tested. The consistency and intensity of activity at latrine sites at the coarse scale, however, was best predicted by characteristics of aquatic habitat beneficial to fish. The findings of this study provide the baseline information necessary for developing techniques for monitoring otter populations and assessing otter habitat that can be incorporated into management, monitoring, and conservation strategies.
Author: Emily A. Bricker
Publisher:
ISBN:
Category : North American river otter
Languages : en
Pages : 98
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Author: Aaron Michael Roe
Publisher: ProQuest
ISBN: 9781109180589
Category : Animal-plant relationships
Languages : en
Pages : 108
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