Summary: Are tropical fungal endophytes hyperdiverse?
Fungal endophytes are ubiquitous fungi that inhabit healthy plant tissues without
causing disease. Endophytes have been found in every plant species examined to date
and may be important, but often overlooked, components of fungal biodiversity. In
two sites in a lowland, moist tropical forest of central Panama, we quantified endophyte
colonization patterns, richness, host preference, and spatial variation in healthy leaves
of two co-occurring, understory tree species [Heisteria concinna (Olacaceae) and Ouratea
lucens (Ochnaceae)]. From 83 leaves, all of which were colonized by endophytes, we
isolated 418 endophyte morphospecies (estimated 347 genetically distinct taxa), most of
which were represented by only a single isolate (59%). Among morphospecies
encountered in more than one leaf (nonsingletons), we found evidence of host
preference and spatial heterogeneity using both morphospecies frequencies and
presence/absence records. Based on these data, we postulate that tropical endophytes
themselves may be hyperdiverse and suggest that extrapolative estimates that exclude
them will markedly underestimate fungal species diversity.
Barro Colorado Island, fungal endophytes, host preference, Jaccard's index,
Ochnaceae, Olacaceae, Panama, tropical forests.
Ecology Letters (2000) 3 : 267±274