Bees not to be? Responses of insect pollinator faunas and flower pollination to habitat fragmentation

AIZEN, M.A. Y P. FEINSINGER

How landscapes change: human disturbance and ecosystem fragmentation in the Americas

SPRINGER

Año: 2003; p. 111 - 129

Many plants rely on animal pollinators to set seed.Therefore, plant-pollinatormutualisms can be critical to the functioning and maintenance of nativeecosystems (Bawa 1974, 1990; Gilbert 1980;; Bawa et al. 1985; Bullock 1985;Feinsinger 1987, Nabhan and Fleming 1993). Some such mutualisms involve charismatic microvertebrates? such as hummingbirds and bats, but ca. 90% of animal-pollinated plants are serviced by less charismatic, often unnoticedinsects. Flies, butterflies, moths, beetles, and most importantly bees areresponsible for a large proportion of all seeds produced by the earth?s wildand cultivated plants (Barth 1991; Buchmann and Nabhan 1996; Kearns andInouye 1997; Kearns et al. 1998). Evidence is accumulating that anthropogenic habitat alteration canstrongly affect the diversity and composition of vertebrate assemblages.Muchless data exist, however, regarding the effects of habitat alteration, for example,fragmentation on assemblages of insects and other invertebrates(Rathcke and Jules 1993; Didham et al. 1996; Kearns et al. 1998). Here, we review the evidence on responses of insect pollinator faunas to fragmentation;propose a variety of possible mechanisms behind the responses; andthen evaluate the links between those responses on the part of pollinators in terms of abundance, species diversity, and assemblage composition andsubsequent responses on the part of the plants in terms of pollination levels and seed production. Along the way, we identify important gaps in knowledgeand suggest areas for further research.