Sarah M Gray

Université de Fribourg · Department Biology

The diversity of a native community is not the sole driving factor determining the success of an invader; abiotic factors can also play a role, making it important to understand their contributions in modifying the expected outcome of biotic and abiotic resistance to invasion. In order to test the contributions of native diversity, relatedness betw...

Microbiomes play essential roles in the health and function of animal and plant hosts and drive nutrient cycling across ecosystems. Integrating novel trait-based approaches with ecological theory can facilitate the prediction of microbial functional traits important for ecosystem functioning and health. In particular, the yield-acquisition-stress (...

Invasive species are considered as one of the key threats to biodiversity and human livelihoods globally. The most effective strategy for handling invasion would be based on profiling invasive species and identifying areas at risk of invasion before they occur. The current study used a trait-environment modelling approach to identify alien species...

One key hypothesis explaining the fate of exotic species introductions posits that the establishment of a self-sustaining population in the invaded range can only succeed within conditions matching the native climatic niche. Yet, this hypothesis remains untested for individual release events. Using a dataset of 979 introductions of 173 mammal speci...

Why do some alien species introductions fail while others are successful? One key hypothesis is that in order for a species to invade a new range, it must initially establish successfully in conditions within its native climatic niche (NCN). Yet, this hypothesis has largely remained untested at the level of individual release events. Using a datase...

Dispersal is key for maintaining biodiversity at local- and regional scales in metacommunities. However, little is known about the combined effects of dispersal and climate change on biodiversity. Theory predicts that alpha-diversity is maximized at intermediate dispersal rates, resulting in a hump-shaped diversity-dispersal relationship. This rela...

Gaining knowledge of how ecosystems provide essential services to humans is of primary importance, especially with the current threat of climate change. Yet little is known about how increased temperature will impact the biodiversity–ecosystem functioning (BEF) relationship. We tackled this subject theoretically and experimentally. We developed a B...

Appendix S1 Methods S1 Additional information on methodological procedures. Table S1 Specialization to abiotic conditions for bacteria grown alone. Table S2 Specialization to abiotic conditions for bacteria and protozoans. Table S3 Specialization to biotic conditions for bacteria and protozoans. Table S4 Relative importance of specialization t...

Understanding how trophic levels respond to changes in abiotic and biotic conditions is key for predicting how food webs will react to environmental perturbations. Different trophic levels may respond disproportionately to change, with lower levels more likely to react faster, as they typically consist of smaller-bodied species with higher reproduc...

Climate change research has demonstrated that changing temperatures will have an effect on community-level dynamics by altering species' survival rates, shifting species' distributions, and ultimately, creating mismatches in community interactions. However, most of this work has focused on increasing temperature, and still little is known about how...

Introduced top predators have the potential to disrupt community dynamics when prey species are naive to predation. The impact of introduced predators may also vary depending on the stage of community development. Early-succession communities are likely to have small-bodied and fast-growing species, but are not necessarily good at defending against...

Temperature is known to influence ecosystem processes through its direct effect on biological rates such as respiration and nutrient cycling. These changes can then indirectly affect ecologically processes by altering trophic dynamics, the persistence of a species in a given environment, and, consequently, its distribution. However, it is not known...

Understanding whether factors important for species establishment in a local community are predictable or context- dependent is key for determining the features that affect community stability and species coexistence. A major challenge for scientists addressing this question is that natural systems are complex. This makes it difficult to test multi...

Background/Question/Methods Sarracenia purpurea is a carnivorous pitcher plant and a model system for aquatic communities. The leaves of this plant species form a pitcher shape and, once they open, they fill with rainwater. An aquatic community of bacteria, protozoans and rotifers form a food web in these detritus-fueled ecosystems. In the plant’...

Background/Question/Methods Leaves of Sarracenia purpurea form pitchers in which communities consisting of bacteria, protozoans and other inquiline species (e.g., mosquito larvae) decompose dead insects and provide nutrients to the plant. This plant originates from North America and was introduced to Switzerland a century ago, where similar types...

Background/Question/Methods Climate change research has demonstrated that changing temperatures will have an effect on community-level dynamics through changes in species’ survival rates, shifts in species’ distributions, and ultimately, mismatches in interactions within a community. However, most of this work has focused on increasing temperatur...

Species introductions of anthropogenic origins are a major aspect of rapid ecological change globally. Research on biological invasions has generated a large literature on many different aspects of this phenomenon. Here, we describe and categorize some aspects of this literature, to better understand what has been studied and what we know, mapping...

The leaves of the carnivorous pitcher plant, Sarracenia purpurea, contain a microscopic aquatic food web that is considered a model system in ecological research. The species identity of the intermediate and top trophic level of this food web, as well the detritivore midge, are highly similar across the native geographic range of S. purpurea and, i...

The development of a community through time, or succession, is generally described as the orderly replacement of species until a deterministic, stable endpoint is reached. However, stochastic factors, coupled with intrinsic biotic factors, such as herbivory or predation, can cause communities within the same habitat to become highly dissimilar in c...

Background/Question/Methods Climate influences ecosystem functioning through its direct effect on the biological rate of species and indirectly through its effect on species distribution and interactions. Understanding the relative importance of these factors is crucial for predicting the impact that climate change will have on ecological systems...

Background/Question/Methods Scientific approaches to literature review, including quantitative methods for research synthesis (meta-analysis), have become more established in ecology over the past 15 years. Formal systematic review protocols, now well established in medical research synthesis, have not yet been widely implemented in ecology. Syst...

Background/Question/Methods Understanding the mechanisms underlying successional patterns of communities has resulted in research varying from investigating the importance of intrinsic (biotic interactions) versus extrinsic (resource input, disturbances) factors in directing the successional trajectory of a community, to testing community assembl...

Background/Question/Methods Characteristics such as high dispersal ability, persistence following low original abundances and competitive ability are thought to help a species become established into a novel community. However, most natural communities are so complex that it is extremely challenging to simultaneously address multiple factors affe...

Background/Question/Methods Propagule pressure and competitive ability have both been found to allow for successful invasion by an introduced species. However, many studies have found that propagule pressure is more important for invasion than competitive ability. Yet due to the complexity of natural systems, it has been extremely difficult to tes...

1. To improve our understanding of the relationship between the pitcher plant ( Sarracenia purpurea ) and the phytotelma community inhabiting its leaves we built an exploratory, mechanistic model based on stochiometric constraints on carbon and nitrogen associated with prey decomposition. 2. Our theoretical results suggest that the phytotelma commu...

Most prior work on the role of top-down and bottom-up effects in aquatic communities has ignored the significant detrital component that occurs in natural systems. We investigated the effects of specific nutrients (carbon, phosphorus, and nitrogen), as well as a top predator (the mosquito Wyeomyia smithii), on the structure of the detritivore commu...