Relocation of habituated black bears in the Klamath Mountains of California: an adaptive management case study

Black bear (Ursus americanus) populations in California have increased in abundance and distribution despite rising trends in the urban encroachment of wildlands. As human-black bear conflicts increase, opportunities to study the relocation of black bears in an adaptive management setting are important for improving the management of this highprofile species. Habituated black bears, some tamed and made tractable through human-controlled food conditioning, were relocated to a remote region of the Klamath Mountains to analyze home range use, survival, return rates, and mortality. Relocated black bears with known outcomes demonstrated an 80% return rate, with 55% not surviving beyond five months. Female bears established home ranges significantly larger than males, and may suggest an enhanced maternal instinct in search of similar nutritional conditions prior to relocation. This study showed that the relocation of food-conditioned black bears resulted in high return rates, poor survival, and risk to public safety.

Home range use in the West Australian seahorse Hippocampus subelongatus is influenced by sex and partner’s home range but not by body size or paired status

Genetic monogamy is the rule for many species of seahorse, including the West Australian seahorse Hippocampus subelongatus. In this paper, we revisit mark-recapture and genetic data of H. subelongatus, allowing a detailed characterization of movement distances, home range sizes and home range overlaps for each individual of known sex, paired status (paired or unpaired) and body size. As predicted, we find that females have larger home ranges and move greater distances compared to males. We also confirm our prediction that the home ranges of pair-bonded individuals (members of a pair known to reproduce together) overlap more on average than home ranges of randomly chosen individuals of the opposite or same sex. Both sexes, regardless of paired status, had home ranges that overlapped with, on average, 6–10 opposite-sex individuals. The average overlap area among female home ranges was significantly larger than the overlap among male home ranges, probably reflecting females having larger home ranges combined with a female biased adult sex ratio. Despite a prediction that unpaired individuals would need to move around to find a mate, we find no evidence that unpaired members of either sex moved more than paired individuals of the same sex. We also find no effect of body size on home range size, distance moved or number of other individuals with which a home range overlapped. These patterns of movement and overlap in home ranges among individuals of both sexes suggest that low mate availability is not a likely explanation for the maintenance of monogamy in the West Australian seahorse.

A triple threat: high population density, high foraging intensity and flexible habitat preferences explain high impact of feral cats on prey

Alien mammalian carnivores have contributed disproportionately to global loss of biodiversity. In Australia, predation by the feral cat and red fox is one of the most significant causes of the decline of native vertebrates. To discover why cats have greater impacts on prey than native predators, we compared the ecology of the feral cat to a marsupial counterpart, the spotted-tailed quoll. Individual prey are 20–200 times more likely to encounter feral cats, because of the combined effects of cats' higher population densities, greater intensity of home-range use and broader habitat preferences. These characteristics also mean that the costs to the prey of adopting anti-predator behaviours against feral cats are likely to be much higher than adopting such behaviours in response to spotted-tailed quolls, due to the reliability and ubiquity of feral cat cues. These results help explain the devastating impacts of cats on wildlife in Australia and other parts of the world.