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Samuel Pinna Hirondelle Varady-Szabo Patrick Boivin Eric Lucas 《Journal of Insect Conservation》2009,13(4):387-397
Urban habitats harbour considerable biological diversity. Ecologists have developed methods to select which habitats should
be conserved. The Ecological value, a method based on vegetation, has been created for the urban habitats of Montreal (Quebec, Canada). The main objective of
our study was to determine if this method was relevant to assess carabid diversity of Mount Royal Park. This index is calculated
using five criteria: uniqueness, representativeness, degree of succession, richness and rarity of the flora, each of which
can influence communities of insects. Ground beetles (Coleoptera: Carabidae) were selected because of their success as biological
indicators. Despite sampling difficulties, our results demonstrate clearly that the Ecological value method does not represent the high carabid richness of urban open habitats (tall grasses) and their specialised native carabid
species. Within forests we found nonetheless that the ecological value index has a significant positive relationship with
native carabid abundance. Moreover, maturity and structure of urban forests were positively correlated with carabid abundance
and richness. Some urban vegetation characteristics have been shown to influence entomological diversity, but the relevance
of using a global floral index to encompass the carabid community seems limited. 相似文献
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Downed woody material (fallen logs) offers ground-dwelling spiders (Araneae) ideal sites for nesting and foraging, but little
is known about what characteristics of dead wood influence spider assemblages. In a maple forest of Forillon National Park,
in eastern Québec (Canada), spider assemblages on, adjacent to, and away from fallen logs were compared. We also tested how
log type (coniferous vs. deciduous) and decomposition stage influenced spider assemblages. Sampling was done for an intensive
four-week period using both litter samples and pitfall traps. A total of 5613 spiders representing 83 species from 16 families
was collected. Spiders were affected by the presence of logs, as both species diversity and total number of individuals collected
were significantly higher on the log surface compared to the forest floor. Ordination analysis revealed a distinct compositional
difference between the spider fauna found on the wood surface compared to the forest floor. Wood type and decomposition stage
had few significant effects on spider assemblages, except that less decayed logs supported higher spider diversity than logs
in advanced stages of decay. Dead wood is clearly important for generalist predators such as spiders, further supporting the
conservation importance of fallen logs in northern forest ecosystems. 相似文献
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