Distribution and ecology of myxomycetes in the high-elevation oak forests of Cerro Bellavista, Costa Rica

Abstract

Myxomycetes associated with a high-elevation (>3000 m) oak forest in the Talamanca Range of Costa Rica were studied for 7 mo. Field collections were supplemented with collections obtained from moist chamber cultures prepared with samples of bark and ground litter of Quercus costaricensis. Various microenvironmental parameters including pH, substrate moisture and diameter, height above the ground and canopy openness were recorded for each field collection, whereas macroenvironmental data for temperature and precipitation were obtained from a meteorological station near the study area. Niche breadth and niche overlap indices were calculated to assess possible resource partitioning by myxomycetes. Thirty-seven species were recorded, including 11 new records for Costa Rica, eight for Central America and one for the neotropics. Both PCA and NMS multivariate analyses indicated that pH and height above the ground explained most of the observed variation, although substrate diameter also seemed to be an important factor. Precipitation showed an inverse correlation with the number of fruitings, confirming its importance as a macroenvironmental factor. Niche overlap values were not higher for closely related species and values for niche breadths were similar for most of the more common species, suggesting that most members of the assemblage of myxomycetes present in the study site are ecological generalists.

Macroecology of high-elevation myxomycete assemblages in the northern Neotropics

“…For example, previous studies have shown that some myxomycete species seem to be very substrate-specific (e.g., Stephenson et al 2008b; or largely influenced by environmental factors (e.g., Rojas and Stephenson 2007). This specificity is likely to have an effect on the macroecological characteristics of different assemblages.…”

“…This has generated a somewhat biased view of the distribution and ecology of myxomycetes in the Neotropics, since some macro-and microhabitats are underrepresented as an artifact of this restricted sampling. In spite of that, recent efforts have been made to alleviate this problem and studies of higher elevation areas in the Neotropics have also been carried out (e.g., Rodríguez-Palma et al 2005;Rojas and Stephenson 2007).…”

Comparison of wood-inhabiting myxomycetes in subalpine and montane coniferous forests in the Yatsugatake Mountains of Central Japan

“…In addition, a highelevation ([3,000 m) oak forest in the Neotropics yielded several species that were the same as the species found in the Japanese subalpine, i.e. Cribraria mirabilis, C. piriformis, C. vulgaris, Lamproderma columbinum, Trichia botrytis and T. verrucosa (Rojas and Stephenson 2007). Thus, these myxomycetes were representative of an association of occurrence with cold climates, which may be favorable for the growth of certain myxomycetes.…”

“…In the present study, five autumnal species of Cribraria in the subalpine forest were different from the montane species and contributed increasing to subalpine species diversity. However, in the recent studies in the Neotropics (Rojas and Stephenson 2007;Lado and de Basanta 2008) those several species of Cribraria were found in high-elevation forests in mountains. It is not necessary to assume that subalpine species form widely distributed in biogeographical mountain element with typical coniferous forests.…”

“…For example, Lado (1993) stated that forest vegetation at different altitudes and in different climatic zones in Mediterranean mountains affected myxomycete assemblages. Recent evidence indicates that the distributions of several myxomycete species involve associations with vegetation or geographical factors Novozhilov et al 2001) and some species respond directly to environmental factors such as pH on a microecological scale (Rojas and Stephenson 2007). Furthermore, occurrence of myxomycetes in relation to the kind of substrate has been reported in several systematic and ecological studies (e.g., Martin and Alexopoulos 1969;Stephenson 1988;Ing 1994) and the preference for wood type, deciduous or coniferous trees, was specifically verified for several myxomycetes ).…”