Urban Nature Reserves Research Articles

Recreation and large mammal activity in an urban nature reserve

Human recreation has immediate and long-term impacts on wildlife, and exposure to recreational activities might be particularly high in urban systems. We investigated the relationship between human recreation and the spatial and temporal activity patterns of large mammals in an urban nature reserve. Data from remotely triggered infra-red cameras (1999–2001) were used to assess activity for bobcat, coyote, mule deer, humans, and domestic dogs along paths in the Nature Reserve of Orange County (NROC), California. Forty-nine camera sites established across the NROC yielded 16,722 images of humans, dogs, and our three target large mammal species during 4232 observation nights. Results suggest that bobcats, and to a lesser degree coyotes, exhibited both spatial and temporal displacement in response to human recreation. Bobcats were not only detected less frequently along trails with higher human activity, but also appeared to shift their daily activity patterns to become more nocturnal in high human use areas; negative associations between bobcat and human activity were particularly evident for bikers, hikers, and domestic dogs. In general, both bobcats and coyotes displayed a relatively wide range of activity levels at sites with low human use, but a lower and markedly restricted range of activity at those sites with the highest levels of recreation. Although we did not find a clear and consistent pattern of avoidance of human recreation by deer, the probability of detecting deer during the day was lower with increasing levels of human recreation. Future studies that experimentally investigate the impacts of recreationists on wildlife, as well as relate behavioral responses to survival and reproduction, will allow further insight of the effects of urban recreation on large mammal populations.

Narrow Host Range Nucleopolyhedrovirus for Control of the Browntail Moth (Lepidoptera: Lymantriidae): Table 1.

The browntail moth, Euproctis chrysorrhoea (L.), is periodically a major urban pest in the southern United Kingdom. High populations cause severe defoliation of a range of host plants, often in urban areas; and urticating hairs of larvae are highly irritating to humans. Control of outbreak populations is therefore desired. As an alternative to chemical insecticide sprays and labor intensive nest removal, nucleopolyhedrovirus (NPV) has been considered as a biological control. To evaluate if use of this spray would affect other lepidopterans we carried out detailed host range testing using a number of wild-caught lepidopteran species. Seventy-three species of Lepidoptera from 14 families, including four species of Lymantriidae and two species of hymenopteran sawfly, were found to be nonpermissive to E. chrysorrhoea NPV at a dose of 106 occlusion bodies per second instar. Some individuals from 11 species of Lepidoptera and one hymenopteran sawfly died of baculovirus infection, but none of these were shown, by dot blot analysis of DNA, to be infected with E. chrysorrhoea NPV. In two of these species, uninfected control larvae also died of infection, indicating that they carried an overt infection in the field. However, in eight species of Lepidoptera and one sawfly, there were no control deaths, providing possible evidence that an inapparent or latent infection had been stressed out of the wild-caught insects by inoculation with a high dose of E. chrysorrhoea NPV. Our results suggest this NPV may be monospecific, and that it is unlikely to present a risk to any nontarget species. These characteristics make it highly suitable for use as a bioinsecticide, particularly in urban areas and nature reserves.

The Ecology of the Common Myna in Urban Nature Reserves in the Australian Capital Territory

SummaryThe Common Myna Acridotheres tristis has increased its population and distribution in Australia since introduction in 1862. It nests in tree hollows and may compete for these resources with native hollow-nesting species. Urban nature reserves comprising open, grassy woodland, with remnant hollow-bearing trees may provide ideal breeding habitat for Common Mynas. This paper examines the ecology of the Common Myna in two such reserves. The birds made extensive use of the reserves for breeding. Feeding activity in reserves (on ground-dwelling invertebrates with some berry feeding) was seasonally variable. Numbers in reserves were highest during the breeding season and lowest over the winter period. Numbers in adjacent suburbs showed the inverse seasonal pattern. There was evidence of differential use of habitat within reserves, with Common Mynas being more prevalent in reserve edges, than in interior or woodland areas. Reproductive performance is compared with published overseas data. Roosting behaviour and defence of territory by Common Mynas are discussed.