Forested riparian belts as reservoirs of plant species in fragmented landscapes of tropical mountain cloud forest

Abstract

Background: Cloud forest in central Veracruz is highly fragmented. However, different arboreal elements are still present within the agricultural matrix, including small patches of secondary forest, isolated trees and forested riparian belts. These elements could be important for cloud forest species conservation.
 Questions: What is the structure and composition of forested riparian belts within current anthropic landscapes, and what is their potential contribution as reservoirs of mountain cloud forest native plant species?
 Studied species: Vegetation community of forested riparian belts of cloud forest.
 Study site and dates: Eastern Mexico (central Veracruz), January to November 2018
 Methods: Along 14 segments of riparian belts (?400 m long), distributed across different tributary streams, six 50 × 2 m transects were placed (three per riverside) per segment. Every plant rooted within a transect and ? 1.5 m in height was identified and measured (height and DBH).
 Results: A total of 2,062 plants from 161 species, 102 genera and 55 families were recorded in the 14 sites (8,400 m² sampled). Structural attributes and floristic composition varied widely amongst sites. Elevation and the amount of forest cover (i.e., area) within 500 m of each sampling site were the most important factors underlying the spatial variation in species composition.
 Conclusions: Riparian belts were remarkably heterogeneous harboring a notable richness of tree and shrub species many of them native of the original cloud forest. This diversity reveals that these arboreal elements are keystone structures for biodiversity conservation and also have a high potential as propagule sources for cloud forest restoration in anthropic landscapes.