Relating Insect Movements to Farming Systems in Dynamic Landscapes

摘要: During the last decade conservation of biodiversity in agricultural landscapes has been greatly emphasized. Intensification production and practices, as well land abandonment, have considered major threats (Solbrig, 1991), by making drastic changes landscape structure composition. The is a shifting mosaic crops, pastures, fallow lands woody areas. Landscape elements exhibit their own disturbance regime, which depends on practices used farmers thus interact with insects at several spatio-temporal scales. Changes regional long-term scales are most documented predictive (Baker, 1989; Rackham, 1986; Odum Turner, 1990; Meeus, 1995; Crumley Marquardt, 1987). A recent trend western Europe decrease area covered non-cultivated such hedgerows, woodlots, heathlands, within intensive (Agger Brandt, 1988; Bunce Hallam, 1993; Burel Baudry, Morant et al., 1995). In mean time large tracks farmland abandoned. Thus contrast between different regions increases. rural result an increase fragmentation many affect insect populations reducing available habitats or seasonal refuges for species. At finer scale, make decisions crop succession farming system management field boundaries non-productive areas; this creates changing mosaic. can only be predicted through knowledge how will change use pattern under circumstances. Two levels must considered: 1) type (e.g. from dairy to cereals) 2) techniques feeding cows hay maize silage). If, broad relationships systems established, it becomes very fuzzy relating to, individual population dispersal. Deffontaines al. (1995) provide examples two farms, Pays d’Auge, where productive one more grassland less annual forage crops. all cases, farm diversity striking, results both physical spatial constraints requirements winter/summer forage). Many factors, out sector, also patterns, multi-job farms (Laurent 1994). Trajectories households barely related scale. consequence ecological point view that cannot derived current patterns (Burel 1990). More specifically, abandonment dereliction stochastic process although deterministic