Three‐dimensional dispersion of drosophilid flies in a cool temperate forest of northern Japan

Abstract

Three-dimensional dispersion of drosophilid flies was studied within a secondary broad-leaved forest in relation to forest structure. The survey area included the forest margin and old canopy gaps and varied in the foliage height profile from place to place. Using multivariate analyses on the data of drosophilid dispersion, five microhabitats which were different from one another for drosophilids were recognized: (i) canopy layer; (ii) middle layer; (iii) floor layer of forest interior; (iv) upper layer of forest margin; and (v) herbaceous layer of forest margin and gap. The height of living space of canopy species was remarkably lowered at the forest margin. The forest edge was richer in both numbers of individuals and species than the forest interior from the overlap of the grassland and the forest canopy subcommunities and the addition of invaders from other habitats. However, no 'edge' species, which were mostly restricted to or spend most of their time in ecotones, were found. It is hypothesized that the above-ground forest structure consists fundamentally of three zones: (i) the canopy; (ii) the floor; and (iii) the edge. A significant positive correlation was found between the foliage height diversity and the degree of vertical habitat segregation among drosophilid species. The patchiness of vegetation structure influential to the three-dimensional dispersion in a forest drosophilid community was estimated to be on the scale of 110-450 m 2. This scale of subjective habitat patchiness or 'ecological neighbourhood' corresponds well with the most prevalent size of canopy gaps occurring in various forests.

Vertical stratification of the termite assemblage in a neotropical rainforest

“…As judged from their foraging range (Levings and Adams 1984) and nest size (Thorne et al 1994;Thorne and Haverty 2000), N. nigriceps is found on a much larger scale than N. corniger and would, therefore, be better adapted to large canopy trees, whereas N. corniger would thrive in the denser network of branches and vines encountered in second-growth areas. Although resemblances between the forest edge and canopy and common features of their faunas have been pointed out (Toda 1992;Didham 1997), the distributions of N. corniger and N. nigriceps suggest that differences in forest structure may be an important factor limiting such similarities. Further studies within the IBISCA framework should reveal whether the distribution of other arthropods follows a congruent pattern.…”

“…However, because microclimatic conditions as well as dead wood distribution and accessibility (Bohlman et al 1995;Yanoviak and Kaspari 2000;Madigosky 2004) differs between the ground and the canopy, the wood-feeding guild is likely to comprise different species in each habitat. In particular, the canopy should accommodate species that are good colonizers and resistant to dry conditions; if present in the lower strata, such species should be more frequently encountered at the edge of the forest than in the interior (Toda 1992;Didham 1997).…”

Arthropod vertical stratification in temperate deciduous forests: Implications for conservation-oriented management

“…in determining these patterns (e.g., Nielsen and Ejlersen, 1977;Rowe and Potter, 1996;Brown et al, 1997;Thomas et al, 2010). Finally, it should be mentioned that the outer layer of foliage often extends uninterrupted from the upper canopy to the ground at forest edges, bringing species normally restricted largely to the tree tops in close proximity to the forest floor (Toda, 1987(Toda, , 1992Wermelinger et al, 2007).…”

Dispersal of adult aquatic Chironomidae (Diptera) in agricultural landscapes

“…Fowler, Silva & Venticique (1993) reported in several families that significantly more insects were present at a forest edge than in the understory. Dispersion of Drosophilidae was affected by the three-dimensional structure of the foliage (Toda, 1992). Furthermore, Toda (1992) mentioned that the vertical distribution of canopy species was significantly lowered at the forest margin owing to the development of a grass layer at the ecotone.…”