Fido, Fluffy, and wildlife conservation: The environmental consequences of domesticated animals

Humans have created a strong relationship with cats and dogs by domesticating them. Whether owned by a human or living feral, modern domestic cats and dogs interact extensively with people and the environment. The negative interactions between these domesticated animals and wildlife have been discussed in several reviews, but few reports have provided an overview of both the positive and negative impacts these domesticated animals have on wildlife conservation. Here, we describe the diverse issues associated with domestic cats and dogs and wildlife including predation, competition, pathogen transmission, hybridization, behavioural modification, harvest of wild animals for pet food, and creation of human-wildlife conflict. We then discuss their role in supporting conservation efforts (e.g., use in species identification and tracking, biological control), and shaping our social values towards animals and appreciation for nature. Finally, we suggest necessary steps to harmonize our relationship with cats and dogs and the conservation of wildlife. For owned animals, there is potential for pet owners to support conservation efforts through a pet tax' adopted by veterinary clinics and pet stores to be used for wildlife conservation. Moreover, information regarding the impacts of these animals on wildlife and potential solutions (e.g., voluntarily keeping cats and dogs inside or use of "pet curfews", use of bells to alert wildlife to cats) should be made available to owners who are most likely to have an influence on the behaviour of their companion animal

Causes and Consequences of Behavioral Interference between Species

Behavioral interference between species, such as territorial aggression, courtship, and mating, is widespread in animals. While aggressive and reproductive forms of interspecific interference have generally been studied separately, their many parallels and connections warrant a unified conceptual approach. Substantial evidence exists that aggressive and reproductive interference have pervasive effects on species coexistence, range limits, and evolutionary processes, including divergent and convergent forms of character displacement. Alien species invasions and climate change-induced range shifts result in novel interspecific interactions, heightening the importance of predicting the consequences of species interactions, and behavioral interference is a fundamental but neglected part of the equation. Here, we outline priorities for further theoretical and empirical research on the ecological and evolutionary consequences of behavioral interference. Aggressive and reproductive forms of behavioral interference between species are widespread in animals and share many parallels in their underlying causes and their ecological and evolutionary effects.Behavioral interference can determine whether species coexist and, thus, affects species ranges, the persistence of native species, and the spread of invasive species.As species ranges shift under environmental change and new interspecific interactions arise, it will be important to incorporate knowledge of behavioral interference into ecological forecasts and conservation planning.Behavioral interference can drive both divergent and convergent character displacement processes and thereby contribute to phenotypic diversity and speciation.Evidence is accumulating that behavioral interference has shaped large-scale ecological and evolutionary patterns

Sublethal consequences of urban life for wild vertebrates

Urbanization is modifying previously pristine natural habitats and creating "new" ecosystems for wildlife. As a result, some animals now use habitat fragments or have colonized urban areas. Such animals are exposed to novel stimuli that they have not been exposed to in their evolutionary history. Some species have adapted to the challenges they face- A phenomenon known as synurbanization-while others have not. Here we present a review of the sublethal consequences of life in the city for wild vertebrates, and demonstrate that urban animals face an almost completely different set of physiological and behavioural challenges compared to their rural counterparts. We focus on the negative fitness-related impacts of urbanization, but also identify instances where there are benefits to wildlife. The effects of urbanization appear to be both species-and context-dependent, suggesting that although the field of urban ecology is far from nascent, we are still just beginning to understand how the intricacies of biodiversity on our planet are affected by our presence

Short-term and long-term effects of transient exogenous cortisol manipulation on oxidative stress in juvenile brown trout

In the wild, animals are exposed to a growing number of stressors with increasing frequency and intensity, as a result of human activities and human-induced environmental change. To fully understand ho

Oxidative stress and partial migration in brown trout (Salmo trutta)

During migration, animals are typically limited by their endogenous energetic resources that must be allocated to the physiological costs associated with locomotion, as well as avoiding and (or) compensating for oxidative stress. To date, there have been few attempts to understand the role of oxidative status in migration biology, particularly in fish. Semi-anadromous brown trout (Salmo trutta L., 1758) exhibit partial migration, where some individuals smoltify and migrate to sea, and others become stream residents, providing us with an excellent model to investigate the link between oxidative stress and migration. Using the brown trout, we obtained blood samples from juveniles from a coastal stream in Denmark in the fall prior to peak seaward migration that occurs in the spring, and assayed for antioxidant capacity (oxygen radical absorbance capacity) and oxidative stress levels (ratio of oxidized to reduced glutathione). We found that individuals that migrated had higher antioxidant capacity than residents and that future migration date was negatively correlated with both antioxidant capacity and body length in the fall. This study provides the first evidence that oxidative status is associated with migration strategy and timing, months in advance of the actual migration, and provides insight into the role of oxidative status in animal migration

Size-Dependent Consequences of Exogenous Cortisol Manipulation on Overwinter Survival and Condition of Largemouth Bass

Little is known about the size-dependent consequences of stressors on wild animals, which is particularly relevant during winter where size-specific trends in survival are common. Here, exogenous cortisol manipulation was used to investigate the effect of a physiological challenge on overwinter mortality and spring condition of largemouth bass (Micropterus salmoides) across a range of body sizes. Fish were wild-caught in the fall, assigned into either control or cortisol manipulated treatments, and held in replicated experimental ponds. For bass that survived the winter, length, mass, and health metrics (e.g., gonadosomatic index [GSI], hepatosomatic index [HSI], and water content) were determined in the spring. Winter survival was marginally lower for cortisol treated bass; however, there was no influence of initial length, mass, or condition on overwinter survival. When bass were grouped by size, survival was significantly higher for bass 300–350 mm in length compared to those <200 mm. The treatment did not strongly influence spring health metrics, suggesting that largemouth bass that survived the winter were able to recover from the effects of the cortisol elevation. Initial size and sex were linked to some spring health metrics, with large females having the highest GSI and HSI scores. Overall, results from this study do not support the notion that there are size-dependent responses to cortisol manipulation in a teleost fish. Rather, this type of physiological challenge may modulate the natural rates of winter mortality that are primarily driven by starvation and predation, independent of body size, in subadult and adult largemouth bass

Morphological, physiological and dietary covariation in migratory and resident adult brown trout (Salmo trutta)

The causes and consequences of trait relationships within and among the categories of physiology, morphology, and life-history remain poorly studied. Few studies cross the boundaries of these categories, and recent reviews have pointed out not only the dearth of evidence for among-category correlations but that trait relationships may change depending on the ecological conditions a population faces. We examined changes in mean values and correlations between traits in a partially migrant population of brown trout when migrant sea-run and resident stream forms were breeding sympatrically. Within each sex and life-history strategy group, we used carbon and nitrogen stable isotopes to assess trophic level and habitat use; assessed morphology which reflects swimming and foraging ability; measured circulating cortisol as it is released in response to stressors and is involved in the transition from salt to freshwater; and determined oxidative status by measuring oxidative stress and antioxidants. We found that sea-run trout were larger and had higher values of stable isotopes, cortisol and oxidative stress compared to residents. Most groups showed some correlations between morphology and diet, indicating individual resource specialization was occurring, and we found consistent correlations between morphology and cortisol. Additionally, relationships differed between the sexes (cortisol and oxidative status were related in females but not males) and between life-history strategies (habitat use was related to oxidative status in male sea-run trout but not in either sex of residents). The differing patterns of covariation between the two life-history strategies and between the sexes suggest that the relationships among phenotypic traits are subjected to different selection pressures, illustrating the importance of integrating multiple phenotypic measures across different trait categories and contrasting life-history strategies