Future range dynamics of the red alga Capreolia implexa in native and invaded regions: contrasting predictions from species distribution models versus physiological knowledge

Philipp Laeseke,Andrés Mansilla,Brezo Martínez,Kai Bischof

doi:10.1007/s10530-019-02186-4

Abstract

Correlative species distribution modelling is a widely used method to predict potential species ranges but can suffer from limitations in integrating species’ fundamental niches. Therefore, they might underestimate suitable ranges, but including physiological information can improve accuracy of predictions and help identify mechanisms of e.g. range limitation. However, approaches using both, results from correlative as well as physiological investigations are rare, especially in research on seaweeds. Here, we provide results from both approaches to predict the suitable habitat range of Capreolia implexa (Rhodophyta) in its native range (Australia and New Zealand) and invaded range (Chile) under present and future climate scenarios (year 2100, rcp 2.6 and rcp 8.5). We used the Maxent modelling technique and physiological knowledge from a temperature tolerance experiment (2–20 °C) for thermal niche estimation. Results from both approaches suggest larger suitable habitat ranges under present day conditions for both regions than currently occupied. Abiotic range limitation in the native range led to underestimation of the suitable temperature range by Maxent (here lower temperature limit = 8.3 °C). Predictions based on the laboratory temperature tolerance experiment suggest additional suitable habitat in colder regions (here lower temperature limit = 6.6 ± 0.4 °C). Under future climate conditions, both native and invaded ranges should shift southward, which will lead to an overall loss of suitable habitat in the native range. Like that, rcp 8.5 conditions should reduce the native range to 50% of the present-day extent. We demonstrate the limitation of correlative SDM modelling for species that live on continental margins and that physiological experiments can help to identify species’ niches beyond correlative analyses, providing valuable information for range projections. Furthermore, we provide valuable insights relevant for both invasion management and conservation.Graphic abstract

Highlights

Climate change is the major driving force for distributional range shifts from the equator poleward (Chen et al 2011)
Since only the temperature range from 2 to 20 °C was included in the experiment and there was no negative growth at the higher temperatures, projections were restricted to areas within this range and no shift of the northern distribution limit could be investigated
In Australia and New Zealand, the lt50 was not found along the coastlines, but only south of the landmasses in the ocean

Summary

Introduction

Climate change is the major driving force for distributional range shifts from the equator poleward (Chen et al 2011). This force affects terrestrial and marine species alike, regardless of taxonomic group (Harley et al 2006; Sorte et al 2010; Chen et al 2011). While climate change leads to loss of species-specific biomass in lower latitudes, it may facilitate higher biomass and productivity in regions of higher latitudes (e.g. Krause-Jensen et al 2007; Krause-Jensen et al 2012; Bartsch et al 2016). By pushing species towards continental margins, range contractions can occur, leading to an overall loss of suitable habitat or even extinction (e.g. poleward shifts in Australia and New Zealand, Wernberg et al 2011). Non-indigenous species can have vast deleterious effects on recipient ecosystems, and bioinvasions are considered a major threat to biodiversity and community structure (Ruiz et al 1997; Casas et al 2004; Klein and Verlaque 2008; Raffo et al 2009)

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Results

Conclusion