Species Diversity Associated with Foundation Species in Temperate and Tropical Forests

Aaron Ellison,David Orwig,Jess Zimmerman,Hannah Buckley,Bradley Case,Jonathan Myers,Álvaro Duque,Dairon Cardenas,James Lutz

doi:10.3390/f10020128

Abstract

Foundation species define and structure ecological communities but are difficult to identify before they are declining. Yet, their defining role in ecosystems suggests they should be a high priority for protection and management while they are still common and abundant. We used comparative analyses of six large forest dynamics plots spanning a temperate-to-tropical gradient in the Western Hemisphere to identify statistical “fingerprints” of potential foundation species based on their size-frequency and abundance-diameter distributions, and their spatial association with five measures of diversity of associated woody plant species. Potential foundation species are outliers from the common “reverse-J” size-frequency distribution, and have negative effects on alpha diversity and positive effects on beta diversity at most spatial lags and directions. Potential foundation species also are more likely in temperate forests, but foundational species groups may occur in tropical forests. As foundation species (or species groups) decline, associated landscape-scale (beta) diversity is likely to decline along with them. Preservation of this component of biodiversity may be the most important consequence of protecting foundation species while they are still common.

Highlights

Foundation species define and structure ecological communities and entire ecosystems through bottom-up control of species diversity and non-trophic modulation of energy and nutrient cycles [3]
Forest Structure and Species Diversity entire plots and within the 20 × 20-m subplots, abundance of 35of the hypothesized foundation species and other focal species was highest in the three temperate plots (Table 1, Figure 6)
Presented data showing a peak in the size of functional-trait more likely in comparatively species-poor temperate forests because functional redundancy among spacewould for tree be assemblages growing at mid-latitudes but more trees there much less common than in species-rich

Summary

Introduction

Foundation species (sensu [1,2]) define and structure ecological communities and entire ecosystems through bottom-up control of species diversity and non-trophic modulation of energy and nutrient cycles [3]. Because foundation species are likely to control the distribution and abundance of such rare species, it has been argued that foundation species should be protected before their populations decline to non-functional levels or disappear entirely [6]. It can take many years—often decades—to acquire sufficient data to distinguish foundation species from species that are common or abundant but lack “foundational” characteristics. In part, this is because the non-trophic effects of foundation species [3] usually are more subtle and harder to detect than trophic (“who-eats-whom”)

Methods

Results

Discussion

Conclusion