Population expansion of the invasive Pomacentridae Chromis limbata (Valenciennes, 1833) in southern Brazilian coast: long-term monitoring, fundamental niche availability and new records.

Antônio B Anderson,Jodir Pereira Da Silva,Carlo Leopoldo B Francini,João P Barreiros,Raquel Sorvilo,Sergio R Floeter

doi:10.1111/jfb.14365

Abstract

Human-mediated species invasions are recognized as a leading cause of global biotic homogenization and extinction. Studies on colonization events since early stages, establishment of new populations and range extension are scarce because of their rarity, difficult detection and monitoring. Chromis limbata is a reef-associated and non-migratory marine fish from the family Pomacentridae found in depths ranging between 3 and 45 m. The original distribution of the species encompassed exclusively the eastern Atlantic, including the Azores, Madeira and the Canary Islands. It is also commonly reported from West Africa between Senegal and Pointe Noire, Congo. In 2008, vagrant individuals of C. limbata were recorded off the east coast of Santa Catarina Island, South Brazil (27° 41' 44″ S, 48° 27' 53″ W). This study evaluated the increasing densities of C. limbata populations in Santa Catarina State shoreline. Two recent expansions, northwards to São Paulo State and southwards to Rio Grande do Sul State, are discussed, and a niche model of maximum entropy (MaxEnt) was performed to evaluate suitable C. limbata habitats. Brazilian populations are established and significantly increasing in most sites where the species has been detected. The distributional boundaries predicted by the model are clearly wider than their known range of occurrence, evidencing environmental suitability in both hemispheres from areas where the species still does not occur. Ecological processes such as competition, predation and specially habitat selectivity may regulate their populations and overall distribution range. A long-term monitoring programme and population genetics studies are necessary for a better understanding of this invasion and its consequences to natural communities.

Highlights

Human-mediated climate change is the main cause of irreversible changes in marine ecosystems, such as ocean warming and acidification, biodiversity loss, declines and distributional shifts in marine species populations (Booth et al, 2017; Pecl et al, 2017)
Macroecological niches of C. limbata were modelled using the MaxEnt – a machine learning algorithm (R package dismo v1.1–4) which consists of a technique based on the principle of maximum entropy – using species' presence data as proposed by Philips and Dudík (2008)
This study indicated that C. limbata populations in Santa Catarina State vary over time and are expanding in space, obeying the general patterns of invasive species

Summary

| INTRODUCTION

Human-mediated climate change is the main cause of irreversible changes in marine ecosystems, such as ocean warming and acidification, biodiversity loss, declines and distributional shifts in marine species populations (Booth et al, 2017; Pecl et al, 2017). The blue spotted cornetfish Fistularia commersonii Rüppell, 1838, colonized nearly the entire Mediterranean in just 7 years, threatening over 41 taxa of native fish species (Kletou et al, 2016). Adults inhabit rocky reefs and sand-weed bottoms (Allen, 1991; Anderson et al, 2017). They are oviparous and have distinct pairing during breeding. Confirmed for the state of Rio Grande do Sul (Parcel de Torres – 29 420 4.6000 S, 48 280 40.3200 W) (Figure 1)

| MATERIALS AND METHODS

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| RESULTS

| DISCUSSION

| CONCLUSIONS