The effect of landscape composition on colonization success, growth rate and dispersal in introduced bush‐crickets Metrioptera roeseli

Abstract

Summary1. Fragmentation and habitat loss affects both existing and introduced populations. Small habitat areas may have harsher biotic and abiotic conditions, as well as restricting population sizes. Loss of connectivity reduces the opportunities for individuals to move between patches to rescue populations or to re-colonize patches. Knowledge of how landscape composition affects the introduced populations is therefore essential for successful management and future re-introductions. 2.To study the effect of landscape composition and structure on the success of colonization, population growth and dispersal distances, we introduced Roesel's bushcrickets Metrioptera roeseli to 70 habitat islands in areas previously unoccupied by the species. The introduction sites differed in habitat area and connectivity. The population survival and dispersal were then studied for 5 years after initial introductions. 3. In addition to results showing the importance of suitable habitat for population persistence, connectivity in form of linear landscape elements and nodes was also crucial. Linear landscape elements and / or nodes were important for colonization success, growth and dispersal. Linear landscape elements and nodes also reduced the negative effects of unsuitable habitat (matrix) and isolation from suitable habitat and on the populations. 4. These results stress the importance of connectivity in the landscape for population survival and establishment. Consideration of this should be taken into account in both management and re-introductions of bush-crickets and other invertebrates with similar population characteristics and behaviour.

Landscape structure affects dispersal in the greater white-toothed shrew: Inference between genetic and simulated ecological distances

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Soil macrofaunal communities along an abandoned rice field chronosequence in Northern Argentina

“…However, it is very difficult to determine whether habitat quality or dispersal limitations constitute the main constraint upon soil recolonisation after culture. The structure and composition of the landscape may also play an important role (With and King, 1999;Berggren et al, 2001). Very few data are available on soil macrofaunal dispersal ability and strategy, and we believe that in addition to these important factors, the landscape structure itself needs to be more precisely understood.…”

Are hedgerows effective corridors between fragments of woodland habitat? An evidence-based approach

“…For example, large numbers of hedgerow connections into a wood may be confounded by greater habitat diversity in the surrounding landscape (i.e., several small fields with associated field margins that may promote species presence), or hedgerows may function as additional areas of habitat for species to inhabit thereby increasing population densities within the woodland fragments. Studies included into the systematic review were grouped by taxon because the efficiency of corridors depends on the relationship between space-use behaviour and landscape configuration for each particular taxonomic group (Collinge 2000;Berggren et al 2001). Ideally, qualitative 'vote-counting' assessment (i.e., scoring the results of each study as positive, neutral or negative in relation to the effect of hedgerow presence on the outcome measure, and then adding them up to provide an overall summary of effect) should be undertaken on the studies accepted into a qualitative systematic review.…”