Vascular Epiphytic Diversity in a Neotropical Transition Zone Is Driven by Environmental and Structural Heterogeneity

Abstract

Vascular epiphytes contribute significantly to tropical diversity. Research on the factors that determine vascular epiphytic diversity and composition in tropical areas is flourishing. However, these factors are entirely unknown in tropical-temperate transition zones, which represent the distribution limit of several epiphytic species. We assessed the degree to which climatic and structural variables determine the diversity of vascular epiphytic assemblages (VEAs) in a transition zone in Mexico: the El Cielo Biosphere Reserve. We found 12,103 epiphytic individuals belonging to 30 species and 15 genera along a climatic gradient from 300 to 2,000 m a.s.l. Bromeliaceae and Orchidaceae were the most species-rich families. Forests along the windward slope of the Sierra Madre Oriental (semideciduous forest and tropical montane cloud forest) had higher species richness than forests along the leeward slope (pine-oak forest and submontane scrub). Species richness was largely determined by seasonality and, to a lesser degree, by forest structure, whereas abundance was mainly determined by host tree size. Variation in VEAs composition was largely explained by climatic variables, whereas forest structure was not as important. VEAs differed among forest types and slopes in terms of taxonomic and functional composition. For example, certain bromeliad indicator species reflected differences between slopes. Although within-tree epiphytic species richness (alpha diversity) was low in this transition zone relative to other habitats, species turnover among forest types (beta diversity) was high. These findings suggest that each forest type makes a unique and important contribution to epiphytic diversity in this transition zone.

Variation in vascular epiphytic assemblage along altitudinal zone in Temperate forest ecosystem

“…Conspicuously, the epiphyte diversity declined with an increase in altitude but differed from other findings i.e., hump-shaped distribution of epiphytes (Hietz, 1999;Wolf & Alejandro, 2003;. The vertical decline of vascular epiphytes as we move towards higher elevation may be due to stunted forest vegetation near treeline (Kromer et al, 2005), a very low temperature (Rosa-Manzano et al, 2019;Schroter & Obenhuber, 2022), decreased soil fertility (Halbritter, 2018), or could be the result of uneven topography, increase in steep and less top soil depth in high altitude (Timsina et al, 2021).…”

Pteridophytes Diversity and Distribution Along The Elevational Gradient of Mount Penanggungan's Hiking Trail, East Java, Indonesia

“…Ferns (pteridophytes), a cryptogam or non-seed-bearing plant, play a vital role in Indonesia's ecosystem, where over 2000 species of ferns from 40 families have been documented (Hassler, 2022). This enormous fern diversity is primarily the result of Indonesia's vast continental area, climate, geography, and island endemics (de la Rosa-Manzano et al, 2019;Wang et al, 2016). As one of the centers of plant diversity in Southeast Asia, scientific research should emphasize the study of fern diversity.…”

Composition, community structure, and vertical distribution of epiphytic ferns on Cyathea junghuhniana in Gede-Pangrango National Park, Indonesia

“…Epiphytes are a significant component of tropical forests worldwide and contribute significantly to high species diversity found in tropical regions (de la Rosa-Manzano et al 2019;Wang et al 2016). Epiphytes contribute profoundly to the forest diversity and ecosystem processes as the plants have versatile adaptations to a life above ground level and have a vast abundance (Batke 2012).…”