Journal of Insect Conservation

Alaruikka, Diane; Kotze, D.; Matveinen, Katja; Niemelä, Jari

doi: 10.1023/A:1024432830064pmid: N/A

To investigate the effects of urbanization on carabid beetles (Carabidae) and ground dwelling spiders (Araneae) a study was completed along a 20 km urban–rural forest gradient in the Helsinki–Espoo area of southern Finland. To study changes in assemblage structure, abundance and species richness, these taxa were collected in the year 2000 using pitfall traps, which had been placed in four forest sites within each of the urban, suburban and rural zones. We expected to find changes in the abundances and species richnesses in the two taxa across the urban–rural gradient, but did not find any. Our second and third hypotheses, stating that generalist species and small-bodied species should gain dominance along the gradient from rural to urban sites, were partly supported as carabid specialists were more characteristic of suburban and rural environments whereas generalists were more likely to be collected from rural areas compared to suburban or urban sites. Furthermore, medium to large-sized carabid individuals were more likely to be collected in the rural sites compared to urban forests. We found no evidence for significant changes in spider abundance or species richness across the urban–rural gradient in relation to body size or habitat specialization. We suggest that urbanization does not have significant effects on the total abundances and species richnesses in these two taxa. However, individual species responded differently to urbanization, and there were significant differences in the specialization and body sizes of carabids across the gradient.

New, T.R.; Sands, D.P.A.

doi: 10.1023/A:1024425515889pmid: N/A

The threats of rapid urbanisation to Australian butterflies are discussed, and examples given of the taxa of conservation concern and measures for their management. Compounding threats, such as intensive recreational activity in coastal regions, are also important consequences of urbanisation. Maintenance of threatened specialist species and more generalist widespread species may demand rather different approaches for practical conservation. Most species capable of persisting in urban areas depend on their adults adapting to modified habitats, and their immature stages utilising cultivated exotic or native food plants. Exotic weeds and inappropriate fire regimes are recognised as major threats to the survival of species in remnant bushland.

Brown, Keith; Freitas, André

doi: 10.1023/A:1024462523826pmid: N/A

A comparative study of butterfly communities in 15 urban/suburban remnants of tropical semideciduous forest in Campinas (São Paulo state, SE Brazil; 24°S, 47°W), with areas from 1.0 to 252 ha and widely varying histories and environments, shows that the most significant factors, besides area and sampling time, distinguishing the sites and influencing their diversity (80–702 species) and composition are connectivity, permanent water, vegetation, flowers, and human impact (negative, including pollution). The diversified Nymphalidae butterflies (38–213 species) and especially two fermented-bait-attracted groups (Satyrinae, 2–30 species, and Biblidini, 9–44 species), are among the more useful indicators of the quality and diversity of the environments in these fragments. Effective conservation of butterfly communities in tropical cities may be achieved by maintenance of arboreal green corridors along streets and watercourses between moderately large (>10 ha) humid areas, not near to the most built-up or polluted city centre(s), and the inclusion within these areas of ponds or streams, diversified native forest, and open vegetation including abundant nectar-rich flowers.

Small, Emma; Sadler, Jon; Telfer, Mark

doi: 10.1023/A:1024491111572pmid: N/A

Brownfield sites are thought to support a minimum of 12–15% of Britain's nationally scarce and rare invertebrates. The amount of derelict land in Britain is set to decrease dramatically under current home-building and regeneration policies. There is therefore a pressing need for research into the potential importance of brownfield sites for invertebrates. In this study we sampled the carabid fauna of 26 sites, with ages varying between 2–20 years since their formation, to assess whether vegetation succession was an important determinant of invertebrate diversity the West Midlands of England. The work was carried out over the course of one growing season (in 1999), with concurrent surveys of the soil characteristics, vegetation type and land-use history. 63 carabid species were found including 2 nationally scarce species. The most species rich assemblages are found on early successional sites, which persist for 6 years on graded sites and up to 20 years on compacted substrates.

Connor, Edward; Hafernik, John; Levy, Jacqueline; Lee Moore, Vicki; Rickman, Jancy

doi: 10.1023/A:1024426727504pmid: N/A

The San Francisco Bay Area hosts a diverse insect fauna and a dense cluster of urban areas. The high diversity of insects in the Bay Area arises for three primary reasons: its location in the California biotic province, the diverse local environment and the entomologist-area effect. The juxtaposition of high insect diversity and an area intensively used by humans led to the first recorded extinction as well as the first efforts to conserve insects in the United States. Habitat loss due to urbanization, agriculture, and invasive species is largely responsible for local extinctions and reduction in abundance of the remaining species. Invasive species such as the Argentine ant and pathogens causing mortality of oaks and pines are poised to have substantial impacts on the insect fauna of the Bay Area in the near future. Understanding which taxa can or cannot persist in remnant habitat patches within an urban or agricultural matrix, and what management practices would encourage persistence should be a focus of future research. Assessments of population status should be focused on insects at risk of extinction because of their restricted geographic ranges, low vagility, interactions with invasive species, or known reduction in their habitat. Assessments that combine examinations of museum collections, literature, and field surveys might enable determination of the status of many species within the Bay Area. Such an approach might better define the scope and magnitude of the problem of conserving insects in an increasingly urbanized region.

doi: 10.1023/A:1024488030636pmid: N/A

doi: 10.1023/A:1024416028657pmid: N/A