Traits influence detection of exotic plant species in tropical forests.

Decky I Junaedi,Mark A Burgman,Michael A Mccarthy,Gurutzeta Guillera-Arroita,Jane A Catford

doi:10.1371/journal.pone.0202254

Abstract

Detecting exotic plant species is essential for invasive species management. By accounting for factors likely to affect species’ detection rates (e.g. survey conditions, observer experience), detectability models can help choose search methods and allocate search effort. Integrating information on species’ traits can refine detectability models, and might be particularly valuable if these traits can help improve estimates of detectability where data on particular species are rare. Analysing data collected during line transect distance sampling surveys in Indonesia, we used a multi-species hierarchical distance sampling model to evaluate how plant height, leaf size, leaf shape, and survey location influenced plant species detectability in secondary tropical rainforests. Detectability of the exotic plant species increased with plant height and leaf size. Detectability varied among the different survey locations. We failed to detect a clear effect of leaf shape on detectability. This study indicates that information on traits might improve predictions about exotic species detection, which can then be used to optimise the allocation of search effort for efficient species management. The innovation of the study lies in the multi-species distance sampling model, where the distance-detection function depends on leaf traits and height. The method can be applied elsewhere, including for different traits that may be relevant in other contexts. Trait-based multispecies distance sampling can be a practical approach for sampling exotic shrubs, herbs, or grasses species in the understorey of tropical forests.

Highlights

Invasive exotic plant species are a priority for environmental management because they threaten native biodiversity [1] and alter ecosystem processes [2]
We can explain the important effect of height in our study given that it was conducted in the lower layer of the tropical rainforest, which is dense and filled with numerous different plant species (Fig 5), in secondary tropical rainforest [50]
Given trait-based detectability predictions, this study demonstrates that general visual traits can be important factors to consider for exotic species survey effort estimation and detection optimization, aside from sampling / survey designs [56,57,58] and appropriate sampling time [9, 18]

Summary

Introduction

Invasive exotic plant species are a priority for environmental management because they threaten native biodiversity [1] and alter ecosystem processes [2]. Exotic plant species detection in tropical forests this work. All the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Objectives

Methods

Results

Discussion

Conclusion