Mammalian predators have been liberated on many islands to control pests but the desired results have rarely been achieved. The liberation of mongooses on islands in the Caribbean and Pacific is an excellent example of a liberation which had serious repercussions. These were liberated to control rats which caused serious damage in the sugar cane fields and although they reduced the numbers of rats, they also exterminated many species of small mammals and birds. Stoats, ferrets and weasels were liberated in New Zealand in the early 1880's to control rabbits. They appear to have had little effect on rabbit populations and stoats quickly spread into forest areas. It is not now possible to determine the effect these predators had on the native bird populations as the changes in fauna and habitat were complex. Unfortunately no studies of mustelids were made until 1948 when Wodzicki (1950) made a brief study as part of his survey of introduced mammals in New Zealand. The two periods of greatest change for mustelids have been during their spread throughout the country in the 1880's and in the early 1950's when rabbits were successfully controlled. There is little information on changes in density or feeding habits of mustelids during these times. Detailed investigation of the ecology of mustelids in New Zealand was begun by Dr W.H. Marshall, Fulbright Research Scholar from the University of Minnesota, with Animal Ecology Division, D.S.l.R. from September 1960 until June 1961. He examined their ecology in the light of his experience of mustelids in North America where conditions differ markedly from those in New Zealand. I joined Animal Ecology Division in November 1960 to assist Dr. Marshall throughout the remainder of his study, and continued the work after his return to the United States. The ecology of stoats, ferrets and weasels has been investigated in terms of their adaptation to food supplies which differ markedly from those in their native range in the Northern Hemisphere.

Mammalian predators have been liberated on many islands to control pests but the desired results have rarely been achieved. The liberation of mongooses on islands in the Caribbean and Pacific is an excellent example of a liberation which had serious repercussions. These were liberated to control rats which caused serious damage in the sugar cane fields and although they reduced the numbers of rats, they also exterminated many species of small mammals and birds. Stoats, ferrets and weasels were liberated in New Zealand in the early 1880's to control rabbits. They appear to have had little effect on rabbit populations and stoats quickly spread into forest areas. It is not now possible to determine the effect these predators had on the native bird populations as the changes in fauna and habitat were complex. Unfortunately no studies of mustelids were made until 1948 when Wodzicki (1950) made a brief study as part of his survey of introduced mammals in New Zealand. The two periods of greatest change for mustelids have been during their spread throughout the country in the 1880's and in the early 1950's when rabbits were successfully controlled. There is little information on changes in density or feeding habits of mustelids during these times. Detailed investigation of the ecology of mustelids in New Zealand was begun by Dr W.H. Marshall, Fulbright Research Scholar from the University of Minnesota, with Animal Ecology Division, D.S.l.R. from September 1960 until June 1961. He examined their ecology in the light of his experience of mustelids in North America where conditions differ markedly from those in New Zealand. I joined Animal Ecology Division in November 1960 to assist Dr. Marshall throughout the remainder of his study, and continued the work after his return to the United States. The ecology of stoats, ferrets and weasels has been investigated in terms of their adaptation to food supplies which differ markedly from those in their native range in the Northern Hemisphere.

Mesocarnivores occupy critical functional roles in regulating ecosystems and maintaining biodiversity. In the Canadian Rocky Mountains, mustelid species depend heavily on carrion as an important dietary contribution, particularly in winter when resources are scarce. In diverse mesocarnivore communities such as this, sympatric species must balance energetic resource acquisitions through scavenging with avoidance of costly competition dynamics, in a manner that optimizes energetic gain through risk aversion. We examined the nature of spatial-temporal interactions between wolverine (Gulo gulo), American marten (Martes Americana), and short-tailed weasel (Mustela erminea) in the Willmore Wilderness Park in western Alberta. Data were collected from camera traps (n = 59) baited with a simulated scavenging opportunity during winter months between 2006 to 2008. The spatial-temporal dimensions of intraguild competition were evaluated using a multi-model approach. Zero-inflated negative binomial (ZINB) or zero-inflated Poisson (ZIP) regression models were used to identify the competitive and environmental factors that affected (1) species presence/absence and (2) how intensely a species would spatiotemporally optimize a carrion site. A time-to-event analysis was used to quantify the directionality of fine-scale (hourly) reactionary behavioural responses of species to potential sources of competition. An extension of this group of models, the Cox proportional hazard (CPH) model was used to further reveal the relative influence of external environmental variables (i.e. diel period, landcover, and snow depth) on temporal spacing. Pairing CPH and ZINB/ZIP models enables us to recognize the relative contribution of fine-scale spatial and temporal behavioural responses to competitors in shaping coexistence strategies. Our results suggest that facultative scavengers adopt different coexistence mechanisms based on the interspecific competitor and environmental conditions they encounter at carrion sites. We found that carrion use was impacted for all species by competition and snow depth. Marten scavenging behaviours were additionally impacted by habitat character. We also found evidence of fine-scale temporal attraction between marten and wolverine, thought to indicate a shared net-energetic gain at scavenging sites. Our results suggest that mesocarnivore scavengers are likely to adopt spatiotemporal mechanisms to facilitate carrion resource partitioning and adapt to conditions specific to carcass placement in a spatially complex environment. Given their vital ecological roles, it is important that we recognize the ability of individual mustelid species to exploit scavenging opportunities and identify the external factors that influence coexistence. Understanding the factors that drive access to these ephemeral resources will provide valuable information for anticipating impacts of climate change on facultative scavengers in the boreal forests of western Canada. / Graduate / 2022-08-23

<p>Diss. (sammanfattning) Umeå : Univ., härtill 6 uppsatser.</p> / digitalisering@umu

No description available.

A sobre-exploração humana tem causado uma degradação generalizada e perturbação dos ecossistemas de água doce, os mais ameaçados do mundo. A bacia hidrográfica do Rio dos Sinos, no estado do Rio Grande do Sul, é considerada umas mais poluídas do Brasil. Seus cursos d’água estão sob diferentes graus de influência antrópica, bem como seus organismos dependentes. A lontra Neotropical é um mustelídeo semiaquático ameaçado por toda a sua área de distribuição continental onde há conhecimento. Embora a lontra seja um importante organismo para avaliar a qualidade ambiental por apresentar alguma tolerância a ambientes antropizados, pouco se sabe sobre seu status de conservação. Sua biologia, ecologia, comportamento e aspectos populacionais ainda são pouco conhecidos. Considerando isso, uma síntese de aspectos ecológicos e biológicos de Lontra longicaudis foi realizada através de extensa revisão bibliográfica. Além disso, avaliada a influência da qualidade da água em regiões com diferentes níveis de influência antrópica, bem como a estrutura da vegetação nas margens de rios, a sazonalidade e a velocidade da correnteza nos rios sobre a ocorrência de L. longicaudis. O componente experimental deste projeto foi realizado com base em amostragens mensais de material biológico não invasivo em 16 diferentes regiões da bacia do Rio dos Sinos no Rio Grande do Sul, ao longo de 2015. Ademais, foram realizadas entrevistas com moradores como método complementar para confirmar a presença da espécie. Nove novas áreas de registro de L. longicaudis foram confirmadas para o estado. A ocorrência de lontra foi modelada através de modelos lineares generalizados. Áreas com água de melhor qualidade (classes 2 e 3) apresentaram significativamente mais registros que áreas com água de qualidade inferior (classe 4). Adicionalmente, quer a correnteza, quer a época do ano também se mostraram relevantes para explicar os padrões de ocorrência da espécie. Em conclusão, a lontra Neotropical, assim como outros mamíferos semi-aquáticos poderão ser utilizados como bioindicadores de qualidade ambiental, especialmente em ambientes antropizados. No futuro, outras variáveis tais como a fisionomia e estágio de sucessão ecológica da vegetação das margens deverão ser considerados para explicar os padrões de ocorrência de lontra, no sentido de contribuir, de forma mais suportada, para a definição de medidas para a sua conservação. / Human overexploitation has caused the generalized degradation and disturbance of freshwater ecosystems, the most threatened in the world. The Sinos river basin in Rio Grande do Sul state is considered one of the most polluted in Brazil. Watercourses in this basin are under different degrees of anthropogenic influence, as well as all the organisms that depend on that water. The Neotropical otter is a semiaquatic mustelid threatened across its entire distribution area. While the otter is an important organism to evaluate environmental quality due to its intermediate tolerance to modified environments, little is known about its conservation status. Neotropical otter biology, ecology, behaviour and population aspects are still scarcely known. With this is mind, a synthesis of the ecological and biological aspects of Lontra longicaudis was done by means of literature revision. The effect of water quality in regions with distinct levels of anthropogenic influence, as well as vegetation structure, seasonality and flow velocity on otter occurrence was evaluated. The experimental component of this project was made based on monthly samplings of non-invasive biological material in 16 different regions of the Sinos river basin in Rio Grande do Sul in 2015. Moreover, interviews with local residents were made as a complementary method to confirm the species presence. Nine new areas of occurrence were detected in the state. Otter occurrence was modelled through generalized linear models. Areas with water of better quality (classes 2 and 3) presented significantly higher records than areas with water of lower quality (class 4). Additionally, both flow and season were also relevant in explaining the patterns of occurrence of the species. In conclusion, the Neotropical otter, as well as other semiaquatic mammals may be used as bioindicators of environmental quality, especially in human-altered environments. In the future, other parameters such as the physiognomy and the stage of ecological succession of the vegetation should be taken into consideration to explain patterns of otter occurrence, as a means to contribute, in a more sustained way, to the definition of conservation measures for the species.

A sobre-exploração humana tem causado uma degradação generalizada e perturbação dos ecossistemas de água doce, os mais ameaçados do mundo. A bacia hidrográfica do Rio dos Sinos, no estado do Rio Grande do Sul, é considerada umas mais poluídas do Brasil. Seus cursos d’água estão sob diferentes graus de influência antrópica, bem como seus organismos dependentes. A lontra Neotropical é um mustelídeo semiaquático ameaçado por toda a sua área de distribuição continental onde há conhecimento. Embora a lontra seja um importante organismo para avaliar a qualidade ambiental por apresentar alguma tolerância a ambientes antropizados, pouco se sabe sobre seu status de conservação. Sua biologia, ecologia, comportamento e aspectos populacionais ainda são pouco conhecidos. Considerando isso, uma síntese de aspectos ecológicos e biológicos de Lontra longicaudis foi realizada através de extensa revisão bibliográfica. Além disso, avaliada a influência da qualidade da água em regiões com diferentes níveis de influência antrópica, bem como a estrutura da vegetação nas margens de rios, a sazonalidade e a velocidade da correnteza nos rios sobre a ocorrência de L. longicaudis. O componente experimental deste projeto foi realizado com base em amostragens mensais de material biológico não invasivo em 16 diferentes regiões da bacia do Rio dos Sinos no Rio Grande do Sul, ao longo de 2015. Ademais, foram realizadas entrevistas com moradores como método complementar para confirmar a presença da espécie. Nove novas áreas de registro de L. longicaudis foram confirmadas para o estado. A ocorrência de lontra foi modelada através de modelos lineares generalizados. Áreas com água de melhor qualidade (classes 2 e 3) apresentaram significativamente mais registros que áreas com água de qualidade inferior (classe 4). Adicionalmente, quer a correnteza, quer a época do ano também se mostraram relevantes para explicar os padrões de ocorrência da espécie. Em conclusão, a lontra Neotropical, assim como outros mamíferos semi-aquáticos poderão ser utilizados como bioindicadores de qualidade ambiental, especialmente em ambientes antropizados. No futuro, outras variáveis tais como a fisionomia e estágio de sucessão ecológica da vegetação das margens deverão ser considerados para explicar os padrões de ocorrência de lontra, no sentido de contribuir, de forma mais suportada, para a definição de medidas para a sua conservação. / Human overexploitation has caused the generalized degradation and disturbance of freshwater ecosystems, the most threatened in the world. The Sinos river basin in Rio Grande do Sul state is considered one of the most polluted in Brazil. Watercourses in this basin are under different degrees of anthropogenic influence, as well as all the organisms that depend on that water. The Neotropical otter is a semiaquatic mustelid threatened across its entire distribution area. While the otter is an important organism to evaluate environmental quality due to its intermediate tolerance to modified environments, little is known about its conservation status. Neotropical otter biology, ecology, behaviour and population aspects are still scarcely known. With this is mind, a synthesis of the ecological and biological aspects of Lontra longicaudis was done by means of literature revision. The effect of water quality in regions with distinct levels of anthropogenic influence, as well as vegetation structure, seasonality and flow velocity on otter occurrence was evaluated. The experimental component of this project was made based on monthly samplings of non-invasive biological material in 16 different regions of the Sinos river basin in Rio Grande do Sul in 2015. Moreover, interviews with local residents were made as a complementary method to confirm the species presence. Nine new areas of occurrence were detected in the state. Otter occurrence was modelled through generalized linear models. Areas with water of better quality (classes 2 and 3) presented significantly higher records than areas with water of lower quality (class 4). Additionally, both flow and season were also relevant in explaining the patterns of occurrence of the species. In conclusion, the Neotropical otter, as well as other semiaquatic mammals may be used as bioindicators of environmental quality, especially in human-altered environments. In the future, other parameters such as the physiognomy and the stage of ecological succession of the vegetation should be taken into consideration to explain patterns of otter occurrence, as a means to contribute, in a more sustained way, to the definition of conservation measures for the species.

A sobre-exploração humana tem causado uma degradação generalizada e perturbação dos ecossistemas de água doce, os mais ameaçados do mundo. A bacia hidrográfica do Rio dos Sinos, no estado do Rio Grande do Sul, é considerada umas mais poluídas do Brasil. Seus cursos d’água estão sob diferentes graus de influência antrópica, bem como seus organismos dependentes. A lontra Neotropical é um mustelídeo semiaquático ameaçado por toda a sua área de distribuição continental onde há conhecimento. Embora a lontra seja um importante organismo para avaliar a qualidade ambiental por apresentar alguma tolerância a ambientes antropizados, pouco se sabe sobre seu status de conservação. Sua biologia, ecologia, comportamento e aspectos populacionais ainda são pouco conhecidos. Considerando isso, uma síntese de aspectos ecológicos e biológicos de Lontra longicaudis foi realizada através de extensa revisão bibliográfica. Além disso, avaliada a influência da qualidade da água em regiões com diferentes níveis de influência antrópica, bem como a estrutura da vegetação nas margens de rios, a sazonalidade e a velocidade da correnteza nos rios sobre a ocorrência de L. longicaudis. O componente experimental deste projeto foi realizado com base em amostragens mensais de material biológico não invasivo em 16 diferentes regiões da bacia do Rio dos Sinos no Rio Grande do Sul, ao longo de 2015. Ademais, foram realizadas entrevistas com moradores como método complementar para confirmar a presença da espécie. Nove novas áreas de registro de L. longicaudis foram confirmadas para o estado. A ocorrência de lontra foi modelada através de modelos lineares generalizados. Áreas com água de melhor qualidade (classes 2 e 3) apresentaram significativamente mais registros que áreas com água de qualidade inferior (classe 4). Adicionalmente, quer a correnteza, quer a época do ano também se mostraram relevantes para explicar os padrões de ocorrência da espécie. Em conclusão, a lontra Neotropical, assim como outros mamíferos semi-aquáticos poderão ser utilizados como bioindicadores de qualidade ambiental, especialmente em ambientes antropizados. No futuro, outras variáveis tais como a fisionomia e estágio de sucessão ecológica da vegetação das margens deverão ser considerados para explicar os padrões de ocorrência de lontra, no sentido de contribuir, de forma mais suportada, para a definição de medidas para a sua conservação. / Human overexploitation has caused the generalized degradation and disturbance of freshwater ecosystems, the most threatened in the world. The Sinos river basin in Rio Grande do Sul state is considered one of the most polluted in Brazil. Watercourses in this basin are under different degrees of anthropogenic influence, as well as all the organisms that depend on that water. The Neotropical otter is a semiaquatic mustelid threatened across its entire distribution area. While the otter is an important organism to evaluate environmental quality due to its intermediate tolerance to modified environments, little is known about its conservation status. Neotropical otter biology, ecology, behaviour and population aspects are still scarcely known. With this is mind, a synthesis of the ecological and biological aspects of Lontra longicaudis was done by means of literature revision. The effect of water quality in regions with distinct levels of anthropogenic influence, as well as vegetation structure, seasonality and flow velocity on otter occurrence was evaluated. The experimental component of this project was made based on monthly samplings of non-invasive biological material in 16 different regions of the Sinos river basin in Rio Grande do Sul in 2015. Moreover, interviews with local residents were made as a complementary method to confirm the species presence. Nine new areas of occurrence were detected in the state. Otter occurrence was modelled through generalized linear models. Areas with water of better quality (classes 2 and 3) presented significantly higher records than areas with water of lower quality (class 4). Additionally, both flow and season were also relevant in explaining the patterns of occurrence of the species. In conclusion, the Neotropical otter, as well as other semiaquatic mammals may be used as bioindicators of environmental quality, especially in human-altered environments. In the future, other parameters such as the physiognomy and the stage of ecological succession of the vegetation should be taken into consideration to explain patterns of otter occurrence, as a means to contribute, in a more sustained way, to the definition of conservation measures for the species.

Un des objectifs majeurs de l'Ecologie est de comprendre les mécanismes qui facilitent la coexistence des espèces. L'hypothèse de la complémentarité des niches prédit qu'afin de coexister, deux espèces sympatriques doivent différer dans les conditions nécessaires à leur survie pour une des trois principales dimensions écologiques, la dimension spatiale, la dimension temporelle et la dimension alimentaire. Les mécanismes qui permettent la syntopie chez les mammifères terrestres sont complexes et variés et, parmi les méso-carnivores, la sélection d'habitat différentielle est un phénomène très répandu permettant la coexistence. La martre Européenne (Martes martes) et la fouine (Martes foina) sont les deux espèces carnivores sympatriques les plus similaires en termes de phylogénie, morphologie, régime alimentaire et rythme d'activité. Dans une région rurale française (la Bresse) où les deux espèces sont présentes en sympatrie, nous avons montré une sélection de l'habitat différentielle qui pourrait expliquer leur coexistence. En utilisant des suivis télémétriques, nous avons montré que les deux espèces diffèrent dans leur patron d'utilisation des gîtes de repos diurnes (nombre de gîtes, surface couverte par les gîtes, principal habitat utilisé pour le gîte). De plus, à partir d'un nombre important d'individus génotypés, nous avons montré que les différences dans l'utilisation de l'habitat n'ont que de faibles conséquences sur les éléments du paysage qui influent sur les flux de gènes. En effet, alors que nous avons montré un impact négatif de la pression de piégeage plus important pour la fouine que pour la martre, la connectivité pour les deux espèces est principalement assurée par le couvert végétal alors que les routes, le bâti humain et le milieu ouvert la réduisent partiellement. Ces résultats, collectivement avec une comparaison morphométrique et une approche en dynamique de population, fournissent des éléments de réponse quant à ce patron de coexistence et ses conséquences sur ces deux espèces sympatriques / One of the major goals of ecology is to understand the mechanisms which promote species coexistence. The niche-complementarity hypothesis predicts that two sympatric species must differ in their requirements for one of the three main ecological dimensions, i.e. habitat use, diet and activity time, to coexist. Mechanisms that allow for synthopy in terrestrial mammals are complex and varied and, among mesocarnivores, differential habitat selection is a widespread evidenced phenomenon facilitating coexistence. Plus, this differential habitat selection must have consequences on the landscape elements influencing gene flow. It is thus important to gather information on species life history traits in terms of habitat use and selection and in terms of demographic and genetic responses to environmental perturbations. The European pine marten (Martes martes) and the stone marten (Martes foina) are the most similar sympatric carnivores in Europe taking into account phylogenetic relationships, morphology, foraging behaviour, and activity pattern. In a French rural region (Bresse, eastern France) where both species are present in sympatry, we evidenced differential habitat use which could theoretically explain their sympatry. Using telemetry data set, we shown that both species differed in their resting site patterns (number of resting sites, area over which they are distributed, main habitat type used for resting). Additionally, using large data set of genotyped individuals, we found that these habitat use differences have slight consequences on the landscape elements influence on gene flow. Indeed, while we shown a differential negative impact of the trapping pressure on the spatial genetic variation, connectivity in both species is mainly provided by vegetation cover while roads human buildings and open area partially impede it. These results, collectively with morphometric comparison and population dynamics approaches, provided better insights on the pattern and the consequences of the coexistence of the two sympatric species

Data derived largely from ecclesiastical (mostly churchwardens') accounts, foxhunting statistics, local scientific society records and 19th and 20th century literature sources from a wide range of published material, have provided detailed evidence of the status and changes in distribution over the past four centuries in Yorkshire for fox (Vulpes vulpes), badger (Meles meles), otter (Lutra lutra), pine marten (Martes martes), stoat (Mustela erminea), weasel (M. nivalis), polecat (M. putorius), American mink (M. vison), wildcat (Felis silvestris) and domestic cat (Felis catus). In the case of the domestic cat, questionnaire surveys quantified population sizes and predatory activity in rural, suburban and urban situations. Evidence of the former distribution of all the carnivores studied provides a credible historical basis for biodiversity action planning and the substantial archived database and bibliography provide further research opportunities.