Is There an Equivalence between Measures of Landscape Structural and Functional Connectivity for Plants in Conservation Assessments of the Cerrado?

Carlos Tomás López De Pablo,Thais Martins Issii,Elisa Hardt,Rozely Ferreira Dos Santos,Erico Fernando Lopes Pereira-Silva

doi:10.3390/land9110459

Abstract

Landscape connectivity can be assessed based on the physical connection (structural connectivity) or the maintenance of flow among habitats depending on the species (functional connectivity). The lack of empirical data on the dispersal capacity of species can lead to the use of simple structural measures. Comparisons between these approaches can improve decision-making processes for the conservation or restoration of habitats in fragmented landscapes, such as the Cerrado biome. This study aimed to understand the correspondence between the measures of landscape structural and functional connectivity for Cerrado plants. Three landscapes with cerradão patches in a pasture matrix were selected for the application of these metrics based on the functional connectivity of four profiles of plant dispersal capacity. The results showed divergent interpretations between the measures of landscape structural and functional connectivity, indicating that the assessment of biodiversity conservation and landscape connectivity is dependent on the set of metrics chosen. Structurally, the studied landscapes had the same number of cerradão patches but varied in optimal resource availability, isolation, heterogeneity, and aggregation. Functional connectivity was low for all profiles (based on the integral index of connectivity—IIC) and null for species with a low dispersal capacity (based on the connectance index—CONNECT), indicating that species with a medium- to long-distance dispersal capacity may be less affected by the history of losses and fragmentation of the Cerrado in the pasture matrix. The functional connectivity metrics used allowed a more robust analysis and, apparently, better reflected reality, but the lack of empirical data on dispersal capacity and the difficulty in choosing an indicator organism can limit their use in the management and planning of conservation and restoration areas.

Highlights

Landscape connectivity is considered an efficient indirect measure of biodiversity conservation, useful for understanding the effects of environmental changes on organism dispersal [1,2]
According to Connectance Index (CONNECT), the landscapes were 100% connected for medium–long and long distances and null for short distances, while using the Integral Index Connectivity (IIC), the connection was less than 10% for any distance but never null
The results indicate that the Cerrado species with medium–long- and long-distance dispersal capacity would be less affected by the current fragmentation of pasture matrices

Summary

Introduction

Landscape connectivity is considered an efficient indirect measure of biodiversity conservation, useful for understanding the effects of environmental changes on organism dispersal [1,2]. Some studies have examined plant functional connectivity based on propagules [10,11,12,13], but the current knowledge available is still not enough to understand this phenomenon, especially in highly fragmented landscapes [14]. New options have been developed to measure landscape functionality, such as Conefor® [17], which requires empirical data on the dispersal capacity of study species, differentiating connectivity into three types: within a patch, by flow, and by the connections between patches [18]

Objectives

Methods

Findings

Discussion

Conclusion