Modeling species invasions using thermal and trophic niche dynamics under climate change

Abstract

Changing marine temperatures modify the distributional ranges of natural populations, but the success of invasion of new areas depends on local physical and ecological conditions. We explore the invasion by thermophilic species and their ecosystem effects by simulating a sea surface temperature (SST) increase using a trophodynamic model for the northern Adriatic Sea (NAS), in which thermal and trophic niches are explicitly represented for each thermophilic non-indigenous species (NIS) and native species. The NAS acts as a cul-de-sac for local species, preventing a further poleward migration as a response to temperature rise. In this situation, model results showed that effects of warming and invasion produced complex, non-linear changes on biomasses but never resulted in a complete overturn of a group of native species and/or a bloom of invasive ones. Despite this, the diversity index stabilizes at increased values after simulating invasion, possibly indicating that in such enclosed systems the establishment of invasive species could represent an enrichment in ecosystem structure. In addition, the absence of complete species substitution clearly showed the contribution of resident species toward increasing the resilience, i.e., the capability of the system to cope with invasion without changing substantially. Contrasting scenarios highlighted that changes in ecosystem primary production and species adaptation had secondary effects in ecosystem structure, while results for scenarios with different exploitation levels indicated that fishing can destabilize community structure in these change contexts, e.g., reducing community resilience. The results confirmed the importance of an ecological niche approach to analyze possible effects of invasion and highlighted the complexity of dynamics linked to temperature-driven species invasion', in terms of both the predicted strength of impacts and the direction of biomass change.

Recent Trends and Impacts of Fisheries Exploitation on Mediterranean Stocks and Ecosystems

“…but also due to indirect interactions of mixed fisheries (Walters et al, 2005;Mackinson et al, 2009), especially in a fast changing ecosystem such as the Mediterranean. The rapid warming, combined with the expansion of non-indigenous species is definitely changing the suitability of the habitats for traditional commercial species with effects on their resilience to fishing (Libralato et al, 2015). The recent collapse of small pelagic fishery in the Gulf of Lions is a clear example where poor fish growth, size and body condition and ultimately biomass seem to be due to bottom-up control characterized by changes in food availability and increasing potential trophic competition (Brosset et al, 2016).…”

“…Increasing body of research is showing fast spreading of new invasive species in the Mediterranean (Lejeusne et al, 2009;Galil et al, 2014;Parravicini et al, 2015) that can have indirect effects on resident communities and fisheries difficult to quantify (e.g., Libralato et al, 2015). Pollution and marine litter are having strong attention because of the several indirect and direct impacts on both stocks and fisheries (Galgani, 2015).…”

Ecosystem functioning of two marine food webs in the North‐Western Ionian Sea (Central Mediterranean Sea)

“…(e.g., Mutshinda, Finkel, Widdicombe, & Irwin, 2016) and, by describing complex ecological structures, can help disentangle the effects of functional diversity on ecosystem processes (e.g., Holzwarth, Rüger, & Wirth, 2015). Modeling marine food webs has shown great potential for investigating the changes due to environmental variability and climate change (Heymans, Coll, Libralato, Morissette, & Christensen, 2014;Libralato, Caccin, & Pranovi, 2015), exploitation of fishing resources and aquaculture management (Forestal, Coll, Christensen, & Die, 2012;Libralato et al, 2010), as well as pollution, nutrient enrichment and the impact of alien species (Daskalov, 2002;Fulton, 2010;Pranovi et al, 2003).…”

Non‐native marine species in north‐west Europe: Developing an approach to assess future spread using regional downscaled climate projections

“…It has been suggested that in some circumstances non‐native species may enrich ecosystems rather than causing harm (Libralato et al, ), and non‐native species can co‐exist with natives in some instances (Gallagher, Culloty, McAllen, & O'Riordan, ). In addition, some of the species considered in this study could represent a hither‐to unexploited commercial opportunity where they have invaded.…”

“…It has been estimated that non‐native species could cost Europe €20 billion per year in damage caused, and in subsequent eradication programmes (Kettunen et al , ). Distributions of non‐native species are often constrained by the available vectors or mechanisms of introduction, and by the environmental conditions of the receiving areas (Libralato, Caccin, & Pranovi, ). The survival and reproduction of marine non‐native species arriving in a new area are constrained by factors such as temperature and salinity, but also depth, substrate type and food availability; and it is thought that climate change may facilitate their persistence or reproduction in locations not previously habitable (Cook et al, ), and that some species may be ‘lying in wait’ until environmental conditions change (Ziska & Dukes, ).…”