Ecology Letters

Boonekamp, Jelle J.; Salomons, H. Martijn; Bouwhuis, Sandra; Dijkstra, Cor; Verhulst, Simon

doi: 10.1111/ele.12404pmid: N/A

Saul, Wolf‐Christian; Jeschke, Jonathan M.; Eubanks, Micky

doi: 10.1111/ele.12408pmid: 25626585

A better understanding of how ecological novelty influences interactions in new combinations of species is key for predicting interaction outcomes, and can help focus conservation and management efforts on preventing the introduction of novel organisms or species (including invasive species, GMOs, synthetic organisms, resurrected species and emerging pathogens) that seem particularly ‘risky’ for resident species. Here, we consider the implications of different degrees of eco‐evolutionary experience of interacting resident and non‐resident species, define four qualitative risk categories for estimating the probability of successful establishment and impact of novel species and discuss how the effects of novelty change over time. Focusing then on novel predator–prey interactions, we argue that novelty entails density‐dependent advantages for non‐resident species, with their largest effects often being at low prey densities. This is illustrated by a comparison of predator functional responses and prey predation risk curves between novel species and ecologically similar resident species, and raises important issues for the conservation of endangered resident prey species.

Parravicini, Valeriano; Azzurro, Ernesto; Kulbicki, Michel; Belmaker, Jonathan; Byers, James

doi: 10.1111/ele.12401pmid: 25626355

Climatic niche conservatism, the tendency of species‐climate associations to remain unchanged across space and time, is pivotal for forecasting the spread of invasive species and biodiversity changes. Indeed, it represents one of the key assumptions underlying species distribution models (SDMs), the main tool currently available for predicting range shifts of species. However, to date, no comprehensive assessment of niche conservatism is available for the marine realm. We use the invasion by Indo‐Pacific tropical fishes into the Mediterranean Sea, the world's most invaded marine basin, to examine the conservatism of the climatic niche. We show that tropical invaders may spread far beyond their native niches and that SDMs do not predict their new distributions better than null models. Our results suggest that SDMs may underestimate the potential spread of invasive species and call for prudence in employing these models in order to forecast species invasion and their response to environmental change.

Eiserhardt, Wolf L.; Borchsenius, Finn; Plum, Christoffer M.; Ordonez, Alejandro; Svenning, Jens‐Christian; Morlon, Helene

doi: 10.1111/ele.12409pmid: 25604755

When taxa go extinct, unique evolutionary history is lost. If extinction is selective, and the intrinsic vulnerabilities of taxa show phylogenetic signal, more evolutionary history may be lost than expected under random extinction. Under what conditions this occurs is insufficiently known. We show that late Cenozoic climate change induced phylogenetically selective regional extinction of northern temperate trees because of phylogenetic signal in cold tolerance, leading to significantly and substantially larger than random losses of phylogenetic diversity (PD). The surviving floras in regions that experienced stronger extinction are phylogenetically more clustered, indicating that non‐random losses of PD are of increasing concern with increasing extinction severity. Using simulations, we show that a simple threshold model of survival given a physiological trait with phylogenetic signal reproduces our findings. Our results send a strong warning that we may expect future assemblages to be phylogenetically and possibly functionally depauperate if anthropogenic climate change affects taxa similarly.

Fayle, Tom M.; Eggleton, Paul; Manica, Andrea; Yusah, Kalsum M.; Foster, William A.; Jordan, Ferenc

doi: 10.1111/ele.12403pmid: 25622647

Understanding how species assemble into communities is a key goal in ecology. However, assembly rules are rarely tested experimentally, and their ability to shape real communities is poorly known. We surveyed a diverse community of epiphyte‐dwelling ants and found that similar‐sized species co‐occurred less often than expected. Laboratory experiments demonstrated that invasion was discouraged by the presence of similarly sized resident species. The size difference for which invasion was less likely was the same as that for which wild species exhibited reduced co‐occurrence. Finally we explored whether our experimentally derived assembly rules could simulate realistic communities. Communities simulated using size‐based species assembly exhibited diversities closer to wild communities than those simulated using size‐independent assembly, with results being sensitive to the combination of rules employed. Hence, species segregation in the wild can be driven by competitive species assembly, and this process is sufficient to generate observed species abundance distributions for tropical epiphyte‐dwelling ants.