Les salmonidés sont des poissons territoriaux en rivière, soumis à une compétition intense pour l'habitat et la ressource trophique dès les plus jeunes stades. Ces interactions exercent une influence sur la mortalité, la migration et la croissance, avec des intensités variables en fonction de l'ontogénie et des facteurs environnementaux. En Suisse, la truite Salmo trutta L. est l'espèce la plus prisée par les pêcheurs amateurs. La majeure partie des populations fait l'objet de rempoissonnements à partir de juvéniles « estivaux », relâchés au cours de leur premier été. L'élevage en pisciculture de ces individus issus de géniteurs captifs, peut avoir des effets néfastes sur la diversité génétique des populations ainsi que sur la fitness des poissons introduits et celle de leurs descendants. En outre, ces individus sont susceptibles d'affecter la dynamique des populations natives. Certains comportements (agressivité, comportement anti-prédateur ont déjà été analysés en milieu contrôlé, mais les conséquences ont rarement été mesurées précisément en milieu naturel.Ce travail de thèse consiste à évaluer l'intensité des mécanismes biotiques ou densité-dépendants entre poissons natifs et poissons introduits sur la base d'expérimentations en rivière. Les interactions biotiques ont d'abord été décrites au stade juvénile dans une population naturelle résidente. Puis, des expérimentations ont été menées en milieu contrôlé et in situ pour évaluer l'efficacité et les limites de deux méthodes de marquages utilisables sur des jeunes stades de truites : l'implantation de PIT tag et un marquage fluorescent à détection externe utilisant la calcéine. Ces techniques ont été employées pour évaluer les effets de la densité et de la taille des poissons introduits sur les juvéniles sauvages, à partir d'investigations conduites in situ dans trois rivières contrastées. Enfin, les résultats des différentes expériences de marquage-recaptures ont été utilisés pour modéliser la mortalité des poissons introduits, comparativement aux poissons natifs, et rechercher les facteurs environnementaux déterminant la survie.Les résultats montrent l'importance de la régulation densité-dépendante sur la survie apparente (ou taux de recapture) et la croissance des poissons natifs, et les interactions de ces mécanismes avec les facteurs environnementaux, en particulier le débit. Dans les cours d'eau soumis à repeuplement, la survie des poissons natifs est généralement bien supérieure à celle des poissons introduits, excepté dans le cours d'eau à faible pente. La densité introduite n'influence pas directement la survie des poissons introduits et des poissons natifs, mais peut augmenter la dévalaison des individus des deux origines. En agglomérant les données de survie apparente collectées dans les sept rivières de cette étude, les résultats indiquent une augmentation de la mortalité initiale des juvéniles introduits en fonction de la densité. Les caractéristiques morphologiques des cours d'eau influencent à la fois la mortalité initiale et la surmortalité des poissons introduits sur le long terme. Ces résultats doivent être confirmés sur la base d'expérimentations de marquages-recaptures couplés à des relevés environnementaux détaillés. / Stream-dwelling salmonids are territorial; from early-life stages they undergo intense competition for habitat and food. These interactions may affect mortality, migration and growth, at variable intensities in function of ontogeny and environmental factors. In Switzerland, brown trout Salmo trutta L. is the most favoured species by anglers. Most of the populations are subjected to stocking of juveniles, released during their first summer (“summerlings”). The rearing in hatcheries of these individuals, which are the progeny of captive broodstock, can have deleterious effects on the genetic diversity of the populations as well as on the fitness of the introduced fish and their offspring. In addition, these individuals are bound to affect the native population dynamics. Some behaviours (aggression and predator avoidance) have already been studied under controlled conditions, but the consequences have rarely been accurately measured in a natural environment.This thesis aimed to evaluate the intensity of the biotic, i.e. density-dependant, mechanisms between wild and stocked fish through a series of experiments in various rivers. The biotic interactions at the juvenile stage were first described in a natural resident population. Thereafter a series of experiments were carried out in controlled and natural environments to evaluate the efficiency and limitations of two marking techniques suitable for young trout: the implantation of a PIT tag and an externally detectable fluorescent marker using calcein. Both techniques were used to evaluate the effects of density and size of the stocked fish on the wild juveniles, through in situ investigations in three contrasted rivers. Finally the results of the various marking-recapture experiments were used to model the mortality of stocked versus wild fish, and to find the environmental factors that define survival.The results show the importance of the density-dependant regulation on the apparent survival, i.e. recapture rate, and the growth of wild fish, as well as the interactions of these mechanisms with environmental factors, especially water flow. In the rivers subjected to stocking, survival of the native fish is usually much greater than for introduced fish, except in the river with low slope. The stocked density does not influence directly the survival of both stocked and wild fish, but can increase the downstream movement of individuals of both origins. By combining apparent survival data collected from seven streams in this study, results show a density-dependent effect on the initial mortality of stocked juveniles. The morphological characteristics of the rivers influence both initial mortality and delayed over-mortality of the stocked fish. These results must be corroborated through supplementary marking-recapture experiments coupled with detailed environmental records.

1. The success of invasive species is often thought to be due to release from natural enemies. This hypothesis relies on the assumption that species are regulated by top-down forces in their native range and implies that species are likely to be regulated by bottom-up forces in the invasive range. Neither of these assumptions has been consistently supported with insects, a group which include many highly destructive invasive pest species. 2. Winter moth (Operophtera brumata) is an invasive defoliator in North America that appears to be regulated by mortality in the larval stage in its invasive range. To assess whether regulation in the invasive range is caused by top-down or bottom-up forces, we sought to identify the main causes of larval mortality. 3. To measure the importance of different sources of winter moth larval mortality, we used observational and manipulative field studies to measure dispersal, predation, parasitism, disease. We measured the response of larval dispersal in the field to multiple aspects of foliar quality, including total phenolics, pH 10 oxidized phenolics, trichome density, total nitrogen, total carbon, and carbon-nitrogen ration. We also used manipulative laboratory studies to measure the presence of cannibalism and dispersal. 4. Tree-level declines in density were driven by density-dependent larval dispersal of early instars with very little mortality caused by other factors. Later instar larvae dispersed at increased rates from previously damaged vs. undamaged foliage, and field larval dispersal rates were related to proportion of oxidative phenolics in 2015, suggesting that larval dispersal may have been mediated by an induced decline in foliar quality. 5. We conclude that winter moth population densities are regulated in New England by density-dependent larval dispersal possibly mediated by phenolic oxidative capacity. The suggested role of host plant quality in mediating dispersal means that winter moth population densities in New England appear to be regulated by bottom up forces, aligning with the assumptions of the natural enemy release hypothesis. This is the first study known to the authors presenting data showing a negative effect on insect herbivore performance from pH 10 oxidized phenolics.

The catchability coefficient is used in most marine stock assessment models, and is usually assumed to be stationary and density-independent. However, recent research has shown that these assumptions are violated in most fisheries. Violation of these assumptions will cause underestimation of stock declines or recoveries, leading to inappropriate management policies. This project assesses the soundness of stationarity and density independence assumptions using multi-species data for seven stocks and four gears in the U.S. Gulf of Mexico. This study also develops a multi-species methodology to compensate for failures of either assumption. To evaluate catchability assumptions, abundance-at-age was reconstructed and compared with catch-per-unit-effort data in the Gulf. Mixed-effects, Monte Carlo, and bootstrap analyses were applied to estimate time-varying catchability parameters. Gulf data showed large and significant density dependence (0.71, s.e. 0.07, p<0.001) and increasing trends in catchability (2.0% annually compounding, s.e. 0.6%, p < 0.001). Simulation modeling was also used to evaluate the accuracy and precision of seven different single-species and multi-species estimation procedures. Imputing estimates from similar species provided accurate estimates of catchability parameters. Multi-species estimates also improved catchability estimation when compared with the current assumptions of density independence and stationarity. This study shows that multi-species data in the Gulf of Mexico have sufficient quantity and quality to accurately estimate catchability model parameters. This study also emphasizes the importance of estimating density-dependent and density-independent factors simultaneously. Finally, this study shows that multi-species imputation of catchability estimates decreases errors compared with current assumptions, when applied to single-species stock assessment data. / Master of Science

We studied the dynamic of nine populations of Alpine ibex ( Capra ibex ibex ) in five protected areas. We showed a strong effect of age on demographic parameters, with a marked decrease of survival after 10-12 years of age. We also found a high variability of old females' reproduction between populations. Contrary to what is expected for a highly dimorphic species like ibex, males survived as well as females except for old individuals. Winter harshness had a negative impact on survival of old individuals but not on reproduction and survival of young. We conclude that ibex have evolved a highly conservative life-history tactic compared to other ungulates studied to now. From a management viewpoint we also showed that under some circumstances ground counts might provide reliable estimates of ibex population trends.

The processes that determine the structure of plant communities are of considerable practical and theoretical interest. Natural enemies such as herbivores, seed predators and pathogens provide one potentially important influence on plant diversity. I investigated the effects of natural enemies on plant diversity in two contrasting, species-rich plant communities (tropical forests in Panama and temperate grasslands in the UK), focusing on pre-dispersal seed predation by insects, and the mortality of seeds and seedlings caused by soil fungi. In Panama I found that pre-dispersal insect seed predators generate significant levels of mortality in multiple tropical tree species, with high heterogeneity in predation rates among individuals and at different forest sites. Insect seed predators were highly host-specific, consistent with a role in enhancing plant diversity. At Upper Seeds, a calcareous grassland site in the UK, I used manipulative experiments to show that soil fungi increase the diversity of plants propagating from soil seed banks. A parallel experiment in Panama, mimicking germination under light gap conditions, revealed differential effects of fungi among sites, with fungicide treatment appearing to increase the diversity of propagated seedlings at some sites but reducing it at others. These results suggest that the influence of soil fungi on pre-emergence mortality can alter plant diversity, even when post-emergence mortality from fungal pathogens is limited. In Panama, I also tested whether enemy-mediated mortality increases with rainfall, potentially contributing to the positive regional correlations widely observed between precipitation and plant diversity. In contrast to predictions, neither pre-dispersal insect seed predation nor the influence of soil fungi on seedling recruitment were affected significantly by site humidity, or (for soil fungi) with experimentally manipulated soil moisture levels. Overall, my results provide evidence that pre-dispersal seed predators and soil fungi can affect plant recruitment and diversity at early life stages, with potential consequences for the community structure of adult plants.

In ecology literature, there is much data which suggests that conspecific negative density dependence (CNDD) and abiotic disturbances increase biodiversity in forests. This thesis elucidates the notion that not only do these two forces increase diversity, but they may also interact with one another in order to achieve higher levels of biodiversity. Abiotic disturbances, like fires and hurricanes, can indirectly impact conspecific effects because when these forces remove individuals from the landscape, the role of the conspecific effects will change. The interaction of these two factors in biodiversity are explored in an agent based forest simulation through a resource surface. Several different types of abiotic disturbances are simulated with either weak or strong CNDD effects in order to establish that different disturbances and conspecific effects cause certain levels of diversity. The underlying causes for the change in impact is also examined.

It is increasingly recognized that individuals of the same species differ from each other and influence and respond to their environment in unique ways. This thesis deals with size variation among individuals that not only are of the same species but also of similar age. Such variation may develop even when individuals are born in the same environment, i.e. within a cohort. I have studied the sources and consequences of variation within and among cohorts from egg through early ontogeny using young-of-the-year (YOY) perch (Perca fluviatilis) as study organism. In agreement with predictions based on model results only taking exploitative interactions among individuals into account, I found that the broader the initial size distributions were, the more did the degree of size variation among individuals decrease over time. Still, with initially small size variation among individuals, in several experiments also size divergence was observed. Furthermore, size variation among individuals increased more under high compared to at low densities. Increased size variation over time may be explained by size-dependent diet shifts allowing for initially larger individuals to make an early diet shift when the first resource becomes limiting. However, as size divergence also was observed in situations with only shared resources available, it can be concluded that diet shifts are not a prerequisite for size divergence in young animal cohorts. Hence, I also suggest that mechanisms not related to competition for limiting resources, such as genetic variation, stochasticity and behavioural traits must be taken into account, especially when initial size differences are small. The importance of considering size variation among individuals within cohorts was demonstrated in a study of winter mortality in YOY perch cohorts. A large individual size in autumn was shown to increase overwinter survival within cohorts. However, late summer growth rather than average body size reached in autumn explained variation in overwinter survival between cohorts. Higher accumulation to lipid reserves and accordingly lower mortality over winter was observed in years with high growth rates late in the season. In another study I showed that apparent patterns of density-dependent growth can emerge among larval fish, but rather than a result of density-dependent resource limitation this was due to variation in size-selective predation pressure. Individuals in the right end of the size distributions grew in to a high predation pressure from cannibalistic perch when cannibal density was high, coinciding with high larval perch densities. Finally, as substantial size variation among individuals can develop within cohorts, also intra-cohort cannibalism can occur. Using a physiologically structured population model it was shown that the development of size bimodality within cohorts as a result of intra-cohort cannibalism is critically dependent on long hatching periods, high victim densities and density-dependent feedbacks on shared resources. / Det faktum att individer som tillhör samma art skiljer sig från varandra och påverkar och påverkas av sin omgivande miljö på ett unikt sätt tillskrivs allt större betydelse inom ekologin. Den här avhandlingen handlar framför allt om storleksvariation mellan individer som förutom att tillhöra samma art dessutom tillhör samma årsklass. Sådan storleksvariation kan till och med utvecklas mellan individer som föds och växer upp i samma miljö (inom en kohort). Jag har studerat orsaker bakom och konsekvenser av variation inom och mellan kohorter. Som studieorganism har jag använt mig av årsyngel av abborre (Perca fluviatilis). I överensstämmelse med förutsägelser baserade på en modell som enbart tar hänsyn till konkurrens om en gemensam resurs visade det sig såväl i ett dammexperiment som i en naturlig sjö att ju bredare den initiala storleksfördelningen var desto mer minskade graden av variation i kroppsstorlek mellan individer över tid. Å andra sidan, när den initiala variationen var relativt liten observerades i flera oberoende experiment även storleksdivergens över tid mellan individer. Variationen i storlek ökade särskilt i miljöer med höga tätheter av konsumenter (abborrar). För att förstå de bakomliggande mekanismerna av sådana täthetseffekter måste man ta hänsyn till den återkoppling som sker mellan antalet konsumenter och mängden resurser. Ökad storleksvariation över tid skulle kunna förklaras med storleksberoende dietskiften som tillåter individer med en initial storleksfördel att genomgå ett tidigt dietskifte samtidigt som tillgången av den första resursen begränsar övriga individers tillväxt. Eftersom storleksdivergens även observerades i situationer där enbart en delad resurs var tillgänglig kan man dock dra slutsatsen att dietskiften inte är en förutsättning för storleksdivergens inom kohorter. Jag föreslår därför också att mekanismer som inte är relaterade till konkurrens om en begränsad resurs, såsom inneboende variation mellan individer och variation i beteendemönster bör beaktas för att förklara uppkomsten av storleksvariation, speciellt i de fall då den initiala variationen är liten. De resultat som presenteras visar på betydelsen av att ta hänsyn till storleksvariation mellan individer. Storlek efter den första tillväxtsäsongen var viktig för att förklara vilka individer inom en kohort av årsyngel som överlever sin första vinter. För att förklara variation i vinteröverlevnad mellan kohorter (mellan år och sjöar) var däremot hög tillväxt sent på säsongen (oberoende av medelstorlek på hösten) avgörande. Högre ackumulering av fettreserver och lägre mortalitet inom kohorter av årsyngel under vintern observerades under år med hög tillväxt under den senare delen av tillväxtsäsongen. I en annan studie visade jag att mönster som tyder på täthetsberoende tillväxt kan uppkomma hos fiskyngel men att detta fenomen snarare än täthetsberoende resursbegränsning förklaras av variation i storleksberoende predationstryck. De större individerna inom kohorterna växte in i ett högt predationstryck från kannibalistiska abborrar när tätheten av kannibaler var hög, något som samkorrelerade med höga tätheter av yngel. Slutligen, då en hög grad av storleksvariation mellan individer kan utvecklas inom kohorter är även kannibalism mellan individer inom en kohort möjligt. Genom att använda mig av en så kallad fysiologiskt strukturerad populationsmodell kunde jag visa att divergerande tillväxtkurvor mellan kannibaler och deras byten (vilket resulterar i storleksbimodalitet) som ett resultat av kannibalism inom kohorter är beroende av den tid det tar för ynglen att kläcka ut, antalet bytesfiskar per kannibal samt den återkoppling som finns mellan konsumenterna och deras gemensamma resurs (djurplankton).

Two closely-related, different-sized species of geese nest sympatrically south of the Queen Maud Gulf (QMG) in Canadas central arctic. Following a period of high population growth rate in both species within the QMG, the population growth rate of larger-bodied lesser snow geese (Chen caerulescens caerulescens; hereafter snow geese) has slowed most recently to roughly half that observed in smaller-bodied Rosss geese (Chen rossii). I focused on factors that influence productivity and recruitment in these two species, to improve our understanding of life history variation associated with interspecific differences in body size, and to test for density-dependent population responses. I used long-term data (1991 to 2008) to compare spring nutrient reserves, breeding strategies, clutch sizes, nest success, and juvenile survival in Rosss and snow geese breeding at Karrak Lake, Nunavut; a large breeding colony located within the QMG.<p> Long-term patterns of spring body condition (i.e., fat and protein reserves) diverged in prospective breeding female Rosss and snow geese implying that differences in food acquisition ability had become more acute. Snow geese displayed larger reductions in protein and fat reserves through time compared to Rosss geese thereby suggesting a differential density-dependent response in the ability to store nutrient reserves, a prerequisite for breeding in both species. Decreased per capita food availability influenced the timing of reproduction in both species. Nesting phenologies of Rosss and snow geese, adjusted for variation in phenology of local spring climate, have become later by 6.5 and 5.0 days, respectively, since 1991. Nutritional strategies (i.e., reliance on reserves versus local food) used for clutch formation differed between species. Rosss geese displayed greater reliance on stored reserves (i.e., capital breeding) than did snow geese, though both used endogenous reserves (> 62% of yolk protein, > 48% of albumen, and > 73% of yolk lipid) for clutch formation. Rosss and snow geese experienced declines of 28% and 23% in body masses from arrival to post-laying and also until hatch demonstrating that endogenous reserves are the main nutrient sources for incubation. Still, constraints of small size forced Rosss geese to use a mixture of local food plants and reserves for incubation metabolism.<p> I then examined differences in clutch size, nest success, and juvenile survival to understand of the role of recruitment in the interspecific divergence of population trajectories. I did not find strong interspecific differences in clutch size and nest success. Overall, snow geese had a larger mean clutch size, which was expected based on benefits of a larger-body size. Clutch sizes decreased with delays in breeding and decreasing protein reserves of arriving females, although Rosss geese displayed larger declines with decreasing protein reserves. Mean apparent nest success for Rosss geese was 4.5% higher compared to snow geese. Nest success showed large declines (11%) in both species with increasing population size at the breeding colony. However, nest success of snow geese decreased twice as fast with delays in breeding compared to Rosss geese. Last, I found no evidence of negative density dependence in juvenile survival over time. Juvenile survival was higher in snow geese (48%) compared to Rosss geese (38%), consistent with a life history prediction based on body size differences. Despite lower juvenile survival, recruitment by Rosss geese is likely greater than that of snow geese because of earlier sexual maturity, higher breeding probability and/or greater nest success.<p> Ultimately, small body size of Rosss geese may produce an ideal life history schedule under resource limitation at this colony i.e., one that maximizes fitness compared to larger snow geese. Life history characteristics of Rosss geese (e.g., absolutely lower energy requirement, have a flexible breeding strategy, higher reproductive effort, an earlier age of sexual maturity, a shorter breeding cycle allowing delayed arrival and nest initiation on arctic breeding areas, and shorter time required by goslings to attain adult size), in addition to their smaller bill morphology may allow exploitation of a wider niche space (i.e., one that includes marginal quality and low quantity vegetation) relative to snow geese. Because there were no large differences in components of recruitment considered here, other components of recruitment (age of sexual maturity, breeding probability) may be affected more strongly by diminished spring nutrition in snow geese and thus have a larger influence on local population dynamics.

Two closely-related, different-sized species of geese nest sympatrically south of the Queen Maud Gulf (QMG) in Canadas central arctic. Following a period of high population growth rate in both species within the QMG, the population growth rate of larger-bodied lesser snow geese (Chen caerulescens caerulescens; hereafter snow geese) has slowed most recently to roughly half that observed in smaller-bodied Rosss geese (Chen rossii). I focused on factors that influence productivity and recruitment in these two species, to improve our understanding of life history variation associated with interspecific differences in body size, and to test for density-dependent population responses. I used long-term data (1991 to 2008) to compare spring nutrient reserves, breeding strategies, clutch sizes, nest success, and juvenile survival in Rosss and snow geese breeding at Karrak Lake, Nunavut; a large breeding colony located within the QMG.<p> Long-term patterns of spring body condition (i.e., fat and protein reserves) diverged in prospective breeding female Rosss and snow geese implying that differences in food acquisition ability had become more acute. Snow geese displayed larger reductions in protein and fat reserves through time compared to Rosss geese thereby suggesting a differential density-dependent response in the ability to store nutrient reserves, a prerequisite for breeding in both species. Decreased per capita food availability influenced the timing of reproduction in both species. Nesting phenologies of Rosss and snow geese, adjusted for variation in phenology of local spring climate, have become later by 6.5 and 5.0 days, respectively, since 1991. Nutritional strategies (i.e., reliance on reserves versus local food) used for clutch formation differed between species. Rosss geese displayed greater reliance on stored reserves (i.e., capital breeding) than did snow geese, though both used endogenous reserves (> 62% of yolk protein, > 48% of albumen, and > 73% of yolk lipid) for clutch formation. Rosss and snow geese experienced declines of 28% and 23% in body masses from arrival to post-laying and also until hatch demonstrating that endogenous reserves are the main nutrient sources for incubation. Still, constraints of small size forced Rosss geese to use a mixture of local food plants and reserves for incubation metabolism.<p> I then examined differences in clutch size, nest success, and juvenile survival to understand of the role of recruitment in the interspecific divergence of population trajectories. I did not find strong interspecific differences in clutch size and nest success. Overall, snow geese had a larger mean clutch size, which was expected based on benefits of a larger-body size. Clutch sizes decreased with delays in breeding and decreasing protein reserves of arriving females, although Rosss geese displayed larger declines with decreasing protein reserves. Mean apparent nest success for Rosss geese was 4.5% higher compared to snow geese. Nest success showed large declines (11%) in both species with increasing population size at the breeding colony. However, nest success of snow geese decreased twice as fast with delays in breeding compared to Rosss geese. Last, I found no evidence of negative density dependence in juvenile survival over time. Juvenile survival was higher in snow geese (48%) compared to Rosss geese (38%), consistent with a life history prediction based on body size differences. Despite lower juvenile survival, recruitment by Rosss geese is likely greater than that of snow geese because of earlier sexual maturity, higher breeding probability and/or greater nest success.<p> Ultimately, small body size of Rosss geese may produce an ideal life history schedule under resource limitation at this colony i.e., one that maximizes fitness compared to larger snow geese. Life history characteristics of Rosss geese (e.g., absolutely lower energy requirement, have a flexible breeding strategy, higher reproductive effort, an earlier age of sexual maturity, a shorter breeding cycle allowing delayed arrival and nest initiation on arctic breeding areas, and shorter time required by goslings to attain adult size), in addition to their smaller bill morphology may allow exploitation of a wider niche space (i.e., one that includes marginal quality and low quantity vegetation) relative to snow geese. Because there were no large differences in components of recruitment considered here, other components of recruitment (age of sexual maturity, breeding probability) may be affected more strongly by diminished spring nutrition in snow geese and thus have a larger influence on local population dynamics.

Coyote (Canis latrans) range expansion in the Central Appalachian Mountains has stimulated interest in ecology of this predator and potential impacts to prey populations. This is particularly true in the Ridge and Valley Region in western Virginia where white-tailed deer (Odocoileus virginianus) populations are restricted by low nutritional carrying capacity and are subject to two other predators, bobcats (Lynx rufus) and American black bears (Ursus americanus), in addition to an active hunter community. I address two primary objectives of the Virginia Appalachian Coyote Study: to investigate 1) spatial ecology and 2) population dynamics of coyote populations in Bath and Rockingham counties. I deployed 21 GPS satellite collars on 19 coyotes over 32 months. I estimated home range size (mean = 13.46 km², range = 1.23 km² - 38.24 km²) across months using biased-random bridges and second-order habitat selection at four scales using eigenanalysis of selection ratios. I developed a metric to classify social status of individuals as either resident or transient based on stability of home range centers over time. I found evidence for class substructure for selection of territories where adult residents had a higher probability of mortality in high productivity/high risk habitats, compared to subadults and transients that were restricted to less productive habitats. I collected scat samples over five scat surveys across 2.5 years and extracted fecal DNA to identify individual coyotes in a mark-recapture framework. I estimated coyote densities in Bath (5.53 – 9.04 coyotes/100 km²) and Rockingham Counties (2.41 – 8.53 coyotes/100 km²) using a spatial capture-recapture model. Six-month apparent survival was lower in Bath County (Φ_Bath = 0.442, 0.259 – 0.643; Φ_Rockingham = 0.863, 0.269 – 0.991). The Bath County population demonstrated persistence despite high mortality and the Rockingham population demonstrated boundedness with recruitment inverse of changes in density. Findings at both sites suggest density-dependence, and tests of territoriality, presence of transients, and territory turnover demonstrate a capacity for immediate local immigration in response to high mortality in Bath County. I suggest that landscape-level habitat management may be a viable strategy to reduce potential conflicts with coyotes in the region. / Ph. D.