Evaluating the Potential for North American River Otter (Lontra Canadensis) to Serve as a Coastal Indicator Species: Comparison of Trace Metal Data to Bottlenose Dolphin (Tursiops Truncatus) PDF Download
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Author: Jenna Klingsick
Publisher:
ISBN:
Category : Bottlenose dolphin
Languages : en
Pages :
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Book Description
Climate driven events including precipitation and coastal/tidal flooding, along with coastal development, continue to increase across the Southeast region of the United States. These factors facilitate the accumulation of trace elements via non-point source runoff into coastal waterways. Sentinel species, such as the bottlenose dolphin, are utilized in order to study environmental health of coastal ecosystems. This study aims to determine if North American river otters can also be used as a sentinel species due to their comparable traits with dolphins. Liver and hair (from otters) were collected and analyzed for trace elements (Al, As, Cd, Co, Cu, Fe, Mn, Ni, Se, Zn). Between otter and dolphin liver samples trace elements Co, Hg, Ni, Se, and Zn were found to be significantly different. Average concentrations of Hg, Ni, Se, and Zn were higher in dolphins than in otters while Co was higher in otters. A significant positive correlation was found for Hg and Mn between otter liver and hair samples. For dolphins, a significant positive relationship was determined between length and Hg (R2 = 0.509) and Se (R2 = 0.478) concentrations. Significant differences were found for Cu and Fe between male and female otter liver samples. Males were found to have higher average Fe concentrations while females were found to have higher average Cu concentrations. The differences of trace element concentrations between otters and dolphins could be explained by differences in physiological concentrations required for cellular functions and the possibility that otters excrete trace elements through molting mechanisms. These findings indicate that river otters should be considered a sentinel species that can be studied in order to monitor environmental health and provide assessments to humans living near coastal ecosystems.
Author: Jenna Klingsick
Publisher:
ISBN:
Category : Bottlenose dolphin
Languages : en
Pages :
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Book Description
Climate driven events including precipitation and coastal/tidal flooding, along with coastal development, continue to increase across the Southeast region of the United States. These factors facilitate the accumulation of trace elements via non-point source runoff into coastal waterways. Sentinel species, such as the bottlenose dolphin, are utilized in order to study environmental health of coastal ecosystems. This study aims to determine if North American river otters can also be used as a sentinel species due to their comparable traits with dolphins. Liver and hair (from otters) were collected and analyzed for trace elements (Al, As, Cd, Co, Cu, Fe, Mn, Ni, Se, Zn). Between otter and dolphin liver samples trace elements Co, Hg, Ni, Se, and Zn were found to be significantly different. Average concentrations of Hg, Ni, Se, and Zn were higher in dolphins than in otters while Co was higher in otters. A significant positive correlation was found for Hg and Mn between otter liver and hair samples. For dolphins, a significant positive relationship was determined between length and Hg (R2 = 0.509) and Se (R2 = 0.478) concentrations. Significant differences were found for Cu and Fe between male and female otter liver samples. Males were found to have higher average Fe concentrations while females were found to have higher average Cu concentrations. The differences of trace element concentrations between otters and dolphins could be explained by differences in physiological concentrations required for cellular functions and the possibility that otters excrete trace elements through molting mechanisms. These findings indicate that river otters should be considered a sentinel species that can be studied in order to monitor environmental health and provide assessments to humans living near coastal ecosystems.
Author: Brandon Michael Gross
Publisher:
ISBN: 9781303659324
Category :
Languages : en
Pages : 162
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Book Description
Author: Danaan DeNeve Weeks
Publisher:
ISBN:
Category :
Languages : en
Pages : 226
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Book Description
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: Aaron Michael Roe
Publisher: ProQuest
ISBN: 9781109180589
Category : Animal-plant relationships
Languages : en
Pages : 108
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Author: Emily A. Bricker
Publisher:
ISBN:
Category : North American river otter
Languages : en
Pages : 98
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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The North American river otter (Lontra canadensis) was extirpated throughout much of its range but is now recovering in many areas. Consequently, there is a need to determine river otter occupancy and habitat associations. We conducted sign surveys from January to April 2008 and 2009 in eastern Kansas to assess how local- and landscape-scale habitat affects river otter occupancy and how survey methods and habitat affect the detectability of river otter sign. Multiple observers surveyed 3-9 400-m stretches of stream and reservoir shorelines for 110 randomly-selected sites and measured local-scale (within a 100 m buffer of site) habitat variables (e.g., stream order, sinuosity, proportion of land cover types) and landscape-scale (Hydrological Unit Code 14 watershed) habitat variables (e.g., road density, shoreline diversity, proportion of land cover types). We then modeled occupancy and detection probability as a function of these covariates using Program PRESENCE. The overall probability of occupancy accounting for detection probability was 0.329. The best-fitting model indicated river otter occupancy increased with the proportion of woodland cover and decreased with the proportion of cropland and grassland cover at the local scale. The best-fitting model also indicated occupancy increased with decreased shoreline diversity, waterbody density, and stream density at the landscape scale, possibly because of the influence of large reservoirs in the watershed. Occupancy was not affected by land cover or human disturbance at the landscape scale, perhaps due to our relatively homogeneous study area or because river otters are habitat generalists. Detection probability for 400-m surveys was highest in mud substrates (p = 0.600) and lowest in snow (p = 0.180) and litter substrates (p = 0.267). Detection probability for scat was more than double that for tracks, and detection probabilities were 17-64% lower for novice observers than experienced observers. Detection probability also increased with survey length. Sign surveys are a useful technique for monitoring many species, including river otters, and accounting for detection probability will improve estimation of occupancy. Furthermore, understanding the ecological factors and the scale important to river otter occurrence will be useful in identifying areas for restoration and management efforts.
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: Michael D. Brandhagen
Publisher:
ISBN:
Category :
Languages : en
Pages : 170
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Author: Mary Martin Cogliano
Publisher:
ISBN:
Category :
Languages : en
Pages : 234
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Author: Kelly Jo Pearce
Publisher:
ISBN:
Category : Conservation biology
Languages : en
Pages : 130
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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.
