Effects of microenvironmental factors on the diversity and composition of fern and orchid assemblages in an Andean paramo in Peru

Acuña-Tarazona M.; Mehltreter K.; Toledo-Aceves T.; Sosa V.J.; Flores-Palacios A.; Kessler M. · Flora: Morphology, Distribution, Functional Ecology of Plants (2022) · DOI: 10.1016/j.flora.2022.152107

Resumen

Paramos are highly diverse ecosystems of tropical mountains above the tree line, where plant communities are frequently exposed to extreme climatic conditions. In this study, we analyzed the influence of microenvironmental factors (slope, cover of rocks, herbs and shrubs) on the richness, abundance and composition of fern and orchid assemblages in a remote, undisturbed paramo in the Peruvian Andes. We recorded the abundance and the life form (epiphyte, lithophyte, terrestrial) of fern and orchid species in 24 plots. In each plot (10 m × 10 m), we measured the cover of shrubs, herbaceous plants and rocks as well as slope and elevation. In total, we recorded 28 species (1861 individuals) of ferns and 33 species (5067 individuals) of orchids. Approximately 40% of the fern and 36% of the orchid species colonized all three substrates, although the most common life form was terrestrial. The total abundance and richness of ferns increased with shrub cover, whereas the total abundance of orchids decreased with herbaceous cover. Shrub cover also affected the relative abundances of ferns and orchids, depending on species, although no species was restricted to any particular microenvironmental conditions. Our results highlight the importance of shrubs in providing niches for a high fern diversity under the stressful environment of the paramo, while an increasing herbaceous cover appears to outcompete many orchid species. The recorded ferns and orchids contribute substantially to the paramo flora in Peru and included new species documented during this study.

Instituciones: Universidad Nacional Mayor de San Marcos