Variability in the settlement of non-indigenous species in benthic communities from an oceanic island

Léa Riera,Patrício Ramalhosa,Ignacio Gestoso,João Canning-Clode

doi:10.1186/s10152-018-0517-3

Abstract

The introduction of non-indigenous species (NIS) in new environments represents a major threat for coastal ecosystems. A good understanding of the mechanisms and magnitude of the impact of NIS colonisation on native ecosystems is becoming increasingly crucial to develop mitigation measures and prevent new invasions. In this present study, we asked if distinct coastal benthic communities from an oceanic island can have different vulnerability to NIS colonisation process. First, PVC settlement plates were deployed for 1 year on the rocky shore of two different locations of Madeira Island (North versus South coast). Then, we implemented a mesocosm experiment where recruited plate communities were maintained under different levels of NIS propagule pressure in order to assess their vulnerability to NIS colonisation process. Results showed that NIS colonisation success was not influenced by the level of propagule pressure, but however, final colonisation patterns varied depending on the origin of the communities. This variability can be attributed to major structural differences between the preponderant species of each community and therefore to the biotic substrate they offer to colonisers. This study highlights how biotic features can alter the NIS colonisation process and importantly, shows that in an urbanisation context, the nature of the resident communities facing invasions risks needs to be closely assessed.

Highlights

The introduction and spread of non-indigenous species (NIS) causing biological invasions is, along with habitat destruction, considered as a major cause of biodiversity loss worldwide [1, 2]
NMDS revealed a clear segregation between the communities from northern and southern stations (Fig. 3)
The results of the PERMANOVA analysis on the initial composition of the plates used for the experiment confirmed that North and South plates were significantly different in community composition (p = 0.003)

Summary

Introduction

The introduction and spread of non-indigenous species (NIS) causing biological invasions is, along with habitat destruction, considered as a major cause of biodiversity loss worldwide [1, 2]. Biological invasions have recently been considered the second most significant driver of species extinctions [3] and future climate change is predicted to increase the spread of invasive species, accelerating invasions [4]. Non-indigenous species can modify ecosystems by displacing native species, altering habitat characteristics and modifying nutrients, food, light and space availabilities [5]. Criteria used to categorise a species as invasive remains somewhat controversial, but invaders can be characterised as NIS that undergo rapid increases in abundance and/or spatial occupancy with adverse effects on recipient ecosystems [7]. Other definitions specify that the introduction of these species outside of their natural dispersal potential must be caused by human action, whether intentionally or unintentionally [8]

Methods

Results

Conclusion