Determining the Impact of Latitude on Parturition Timing in Captive North American River Otters PDF Download
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Author: Jordan I. Bailey
Publisher:
ISBN:
Category : Latitude
Languages : en
Pages : 110
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Book Description
"Historically, North American river otters (Lontra canadensis) were widely dispersed throughout the North American continent. Trapping pressures and urbanization have led to regional exclusion of North American river otter populations from historic habitats, leading the Association of Zoos and Aquariums to spearhead conservation and captive breeding efforts to maintain genetic diversity of the aquatic mustelid. Difficulties in consistently breeding captive North American river otters have spotlighted a need to understand how geography and life history of adult individuals influence reproductive events. This study analyzed the AZA studbook records for all litters born in captivity from 2008 to 2014 (N = 47) to assess whether any correlations existed between historical data and timing of parturition events. ANOVA tests found significant differences in mean parturition date between litters by dam origin region (F = 6.09, p-value = 0.018) and by parturition location (F = 12.73, p-value = 0.001). A Mann-Whitney u test found a difference (p-value = 0.0365) between median parturition dates of litters born in the north and those born in the south regions. PCA testing showed that the data form independent groups by both dam and sire origin latitudes, confirming the existence of a significant relationship between latitude and the timing of reproductive events. However, this study did not conclusively determine which latitude (the origin of the dam, origin of the sire, or latitude at the time of breeding) has the most influence on reproductive events among the captive North American river otter population. Future work should strive to identify other variables related to physiological condition and/or genetic variation between North American river otter subspecies. These factors may lead to more discreet groups and will likely aid in the development of a predictive model of parturition timing among the captive population using known life history data."--Abstract.
Author: Jordan I. Bailey
Publisher:
ISBN:
Category : Latitude
Languages : en
Pages : 110
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Book Description
"Historically, North American river otters (Lontra canadensis) were widely dispersed throughout the North American continent. Trapping pressures and urbanization have led to regional exclusion of North American river otter populations from historic habitats, leading the Association of Zoos and Aquariums to spearhead conservation and captive breeding efforts to maintain genetic diversity of the aquatic mustelid. Difficulties in consistently breeding captive North American river otters have spotlighted a need to understand how geography and life history of adult individuals influence reproductive events. This study analyzed the AZA studbook records for all litters born in captivity from 2008 to 2014 (N = 47) to assess whether any correlations existed between historical data and timing of parturition events. ANOVA tests found significant differences in mean parturition date between litters by dam origin region (F = 6.09, p-value = 0.018) and by parturition location (F = 12.73, p-value = 0.001). A Mann-Whitney u test found a difference (p-value = 0.0365) between median parturition dates of litters born in the north and those born in the south regions. PCA testing showed that the data form independent groups by both dam and sire origin latitudes, confirming the existence of a significant relationship between latitude and the timing of reproductive events. However, this study did not conclusively determine which latitude (the origin of the dam, origin of the sire, or latitude at the time of breeding) has the most influence on reproductive events among the captive North American river otter population. Future work should strive to identify other variables related to physiological condition and/or genetic variation between North American river otter subspecies. These factors may lead to more discreet groups and will likely aid in the development of a predictive model of parturition timing among the captive population using known life history data."--Abstract.
Author:
Publisher:
ISBN:
Category : Lutra canadensis
Languages : en
Pages : 142
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Book Description
Author:
Publisher:
ISBN:
Category : Captive otters
Languages : en
Pages : 474
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Book Description
The North American river otter (NARO) (Lontra canadensis) is a semi-aquatic mammal found in the wild throughout North America, and captive at many institutions throughout the world. The Association of Zoos and Aquariums' (AZA) captive NARO population represents an important feature species that attracts many patrons to zoological institutions. NAROs are rarely taken from the wild, so captive breeding programs are being utilized to increase the captive population. These captive breeding programs are overseen by the AZA to ensure the genetic diversity of the captive populations, and to encourage proper care and management of the animals. Captive breeding, however, is not always successful. In fact, captive breeding of mustelidae (members of the weasel family) has been a learning experience for all involved; as seen by the easy success of the Black-footed ferret (musetla nigripes), the hit or miss success of the North American river otter (Lontra canadensis), and the lack of success with the sea otter (Enhydra lutris). This research project was initiated to identify factors, such as geographic origin of the breeding pair and zoological practices, that contribute to successful captive breeding. Observations of the Pueblo Zoo (Pueblo, CO) NAROs and their zoological practices were conducted as part of this study. This information was used to create a survey, which asked specific information about the captive NAROs, and the zoological practices that impact thier captivity. The survey was then sent to all AZA institutions that house and attempt breeding with thier captive NAROs. Results from the 30 responding AZA institutinos indicate that having two NAROs from similar geographic locations, both in proximity and latitude of origin, aids in successful captive breeding. No single zoological practice was demonstrated to have a significant impact on successful captive breeding. Despite low response rate, the evidence suggests that successful captive breeding is more likely to occur between NAROs from similar locations, and that, as expected, providing a healthy environment that meets all biological needs may aid in successful captive breeding.
Author: Matthew J. Hasenjager
Publisher:
ISBN: 9781124608556
Category : Captive wild animals
Languages : en
Pages : 79
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Book Description
Author: Janice Reed-Smith
Publisher:
ISBN:
Category : Captive otters
Languages : en
Pages : 25
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Book Description
Author: Olivia R. Beasley
Publisher:
ISBN:
Category : North American river otter
Languages : en
Pages : 130
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Book Description
"While scientists have conducted some behavioral research on wild river otters, detailed studies of interactions are difficult for a species that ranges widely. A full understanding of river otter social patterns requires captive studies, however, as yet few such studies have been done. To help fill this gap we carried out a study of the social behavior of a group of captive river otters. We tested three hypotheses: first, that male otters would engage in more social behavior than females; second, that most social behavior among conspecifics would occur during the early evening; and third, that most social behavior would occur in the terrestrial portion of the exhibit (analogous to latrine sites). Data were collected at the Tennessee Aquarium in Chattanooga, TN, over 8 weeks in June-July 2017"--Abstract, leaf ii.
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:
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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: Evelyn Neunteufel
Publisher:
ISBN:
Category : Captive wild animals
Languages : en
Pages : 174
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Book Description
Author: Joseph R. Geraci
Publisher: National Aquarium in Baltimore
ISBN: 0977460908
Category : Marine mammals
Languages : en
Pages : 386
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Book Description
Comprehensive manual for understanding and carrying out marine mammal rescue activities for stranded seals, manatees, dolphins, whales, or sea otters.
