Traits and Resource Use of Co-Occurring Introduced and Native Trees in a Tropical Novel Forest

Jéssica Fonseca Da Silva,Ernesto Medina,Ariel Lugo

doi:10.3390/f8090339

Abstract

Novel forests are naturally regenerating forests that have established on degraded lands and have a species composition strongly influenced by introduced species. We studied ecophysiological traits of an introduced species (Castilla elastica Sessé) and several native species growing side by side in novel forests dominated by C. elastica in Puerto Rico. We hypothesized that C. elastica has higher photosynthetic capacity and makes more efficient use of resources than co-occurring native species. Using light response curves, we found that the photosynthetic capacity of C. elastica is similar to that of native species, and that different parameters of the curves reflected mostly sun light variation across the forest strata. However, photosynthetic nitrogen use-efficiency as well as leaf area/mass ratios were higher for C. elastica, and both the amount of C and N per unit area were lower, highlighting the different ecological strategies of the introduced and native plants. Presumably, those traits support C. elastica’s dominance over native plants in the study area. We provide empirical data on the ecophysiology of co-occurring plants in a novel forest, and show evidence that different resource-investment strategies co-occur in this type of ecosystem.

Highlights

The Anthropocene Epoch is associated with rapidly changing environmental conditions and high rates of species introductions, leading to the formation of novel forests [1]
It is well known that introduced species—commonly the dominant tree species in novel forests—are generally considered a risk for biodiversity due to their ability to outperform native species in terms of productivity, reproductive capacity, and recruitment (e.g., [7,8])
Photosynthetic capacity was unexpectedly similar among species in the Castilla novel forest

Summary

Introduction

The Anthropocene Epoch is associated with rapidly changing environmental conditions and high rates of species introductions, leading to the formation of novel forests [1]. These emerging forests contain species assemblages that include co-occurring introduced and native tree species [2,3]. It is well known that introduced species—commonly the dominant tree species in novel forests—are generally considered a risk for biodiversity due to their ability to outperform native species in terms of productivity, reproductive capacity, and recruitment (e.g., [7,8]). The ecophysiology of Forests 2017, 8, 339; doi:10.3390/f8090339 www.mdpi.com/journal/forests

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Discussion

Conclusion