High-Light Demanding and Rare Tree Species Define Tropical Riparian Tree Communities

Abstract

Riparian zones are areas of transition between aquatic and terrestrial ecosystems, and their vegetation provides many important ecosystem services that are becoming of greater importance due to the changing climate. To understand riparian conditions along headwater tropical streams in terms of species composition and structure, we surveyed riparian tree communities and physical conditions in adjacent streams in the Luquillo Experimental Forest. We determined riparian substrate condition visually by estimating ground and vegetation attributes and measuring slope and elevation in a series of riparian plots at three stream sites. We determined riparian forest composition by identifying stem species and recording their height and diameter in plots. Our results demonstrated that elevation and slope were the main di!erences among sites, while all sites had similar ground and vegetation conditions. Species composition in all sites was characterized by hydrophytic species. However, although the most abundant species were generalists, we also found many species that were only observed once or twice per site. Overall, our results indicate that although recent and major hurricanes in"uence structure and composition at this site, riparian areas still maintain a large proportion of hydrophytic and rare tree species.

Citation

Hudspeth, V; Pastor, A; Heartsill-Scalley, T. 2023. High-Light Demanding and Rare Tree Species Define Tropical Riparian Tree Communities. Acta Científica. 34(1): 5-15.