Positive effects of exotic species dampened by neighborhood heterogeneity.

It is well known that species interactions between exotic and native species are important for determining the success of biological invasions and how influential exotic species become in invaded communities. The strength and type of interactions between species can substantially vary, however, from negative and detrimental to minimal or even positive. Increasing evidence from the literature shows that exotic species have positive interactions with native species more often than originally thought.

Accounting for demographic uncertainty increases predictions for species coexistence: A case study with annual plants.

Natural systems contain more complexity than is accounted for in models of modern coexistence theory. Coexistence modelling often disregards variation arising from stochasticity in biological processes, heterogeneity among individuals and plasticity in trait values. However, these unaccounted-for sources of uncertainty are likely to be ecologically important and have the potential to impact estimates of coexistence.

Disentangling key species interactions in diverse and heterogeneous communities: A Bayesian sparse modelling approach.

Modelling species interactions in diverse communities traditionally requires a prohibitively large number of species-interaction coefficients, especially when considering environmental dependence of parameters. We implemented Bayesian variable selection via sparsity-inducing priors on non-linear species abundance models to determine which species interactions should be retained and which can be represented as an average heterospecific interaction term, reducing the number of model parameters. We evaluated model performance using simulated communities, computing out-of-sample predictive accuracy and parameter recovery across different input sample sizes.

Requirements for the spatial storage effect are weakly evident for common species in natural annual plant assemblages.

Coexistence in spatially varying environments is theorized to be promoted by a variety of mechanisms including the spatial storage effect. The spatial storage effect promotes coexistence when (1) species have unique vital rate responses to their spatial environment and, when abundant, (2) experience stronger competition in the environmental patches where they perform better. In a naturally occurring southwest Western Australian annual plant system, we conducted a neighbor removal experiment involving eleven focal species growing in high-abundance populations.