Forest loss in the humid tropics proceeds by a combination of fragmentation and degradation. Residual patches of natural forest retain relic populations of plants and animals but their species richness has often been found to decline over time because of local extinctions (Fahrig & Merriam 1994). Nevertheless, many forest organisms are dependent on ecological continuity of old-growth conditions in forest patches for their continued survival. This may be because of their limited ability to colonize new habitats and/or requirements for old-growth microhabitats (Norden & Appelqvist 2001). Although much has been learned recently about the dynamics of plant and animal species populations in fragmented landscapes, virtually nothing is known about the diversity and landscape distribution of fungi. Fungi are key functional components of forest ecosystems and the paucity of knowledge on their responses to forest fragmentation and degradation needs to be addressed. In the humid tropics, where the rates of forest loss are highest, so little is known about the ecology of most species of fungi that it is difficult even to make predictions about the likely impacts of forest fragmentation. One of the principal reasons for the lack of information is the formidable difficulty that fungi present to ecological study (Cannon 1997). Most species are cryptic, rarely or never forming sporocarps, and most species of tropical fungi are undescribed (Hawksworth 2001). Estimates of fungal diversity are therefore based on the identification of morphotypes or other surrogate measures (Cannon 1997).

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Fahrig, L. & Merriam, G. (1994) Conservation at fragmented populations. Conservation Biology, 8, 50–59.
Norden, B. & Appelqvist, T. (2001) Conceptual problems of ecological continuity and its bioindicators.