Evolution is driven by ecological processes, and ecological processes are influenced by evolution. A growing recognition of such eco-evolutionary dynamics highlights a need to study how ecological and evolutionary interactions play out on the time scales most relevant to conservation and management. In light of recent theoretical and empirical advances on community ecology, this symposium will put forward several promising approaches to achieve a deeper understanding of the processes that shape the structure and dynamics of communities as well as the trajectory of evolutionary change of the species inhabiting them. The approaches include: (1) using functional traits, (2) studying biological invasion as a real-time natural experiment, (3) studying range evolution and (4) experimental evolution. Through an overview of the four approaches and general discussion with audience, we will aim to set a new road map towards making ecology a more predictive science, and discuss what we can do to make it happen.

1. Using traits to link evolutionary and ecological mechanisms in communities

Caroline Tucker (University of North Carolina)

An ultimate goal in community ecology is to be able to explain and ultimately predict community diversity and composition. One promising – and potentially general -- approach is to use functional characteristics, rather than species’ identities, to describe population dynamics and community assembly. If functional traits are relevant to ecological processes, then it is essential to understand causes and implications of variation in functional traits among populations, species, and communities. In this talk I will present recent work, from natural plant communities and from laboratory aquatic microcosms, which ask how the potential combinations of traits present at different scales are constrained by both evolutionary and ecological processes? How traits can be incorporated into population and community dynamics? and How rapid evolution can affect ecological processes, through traits? The results suggest that – although some trait-based analyses of communities assume simple, constant relationships between individual traits and demographic rates – the reality is more complex since traits represent the outcomes of complex, interacting set of processes. However, even if the relationships between traits and ecological dynamics is more complex than expected, traits are still a useful tool for understanding ecological systems.

2. Geographic variation of apparent competition via herbivory between exotic and native plants

Yuzu Sakata (Akita Prefectural University)

Exotic plants may compete with native plants not only directly but can indirectly mediated by herbivores (apparent competition). Still few studies tested the combinations of the direct and indirect effects of exotic plants on native plants between native and introduced ranges. Here we aimed to clarify the effects of herbivore mediated indirect effects (apparent competition) of an herbaceous perennial plant Solidago altissima (Asteraceae) on other Asteraceae plants under different insect herbivore communities both in its native range USA and introduced range Japan. We found that S. altissima increased herbivory damage on the native asters by shared herbivores in the introduced range, while this apparent competition was not detected in the native range. Moreover, in areas where a shared exotic herbivore is distributed, the number of flowers of a native plant was especially reduced when planted with S. altissima. These results suggest that the invasion of an exotic herbivore may enhance the negative effect of exotic plants on native plants by increasing the strength of the apparent competition.

3. Which mechanisms do we need to predict biodiversity change?

William Godsoe (Lincoln University)

There is a need to predict how species’ distributions will change in response to environmental change. Unfortunately, our predictions are often uncertain because we lack information on some of the mechanisms shaping each species’ success. In response to this problem I will use the first part of my talk to organize the mechanisms shaping range limits, highlighting the importance of rapid evolution and interactions among species such as competition and predation. I will then argue that biotic interactions are likely to substantially influence range limits, but that their effects are difficult to detect using commonly available data. Given the difficulty in detecting the effects of biotic interactions, we might ask if there are alternative approaches to describe changes in biodiversity. In the second part of my talk I will argue that tools from evolutionary theory might fill this role. I will show that a mechanism analogous to selection among species is far easier to measure than the interactions among species typically studied by ecologists. With this analogy in hand I will present a new approach to measure the mechanisms shaping biodiversity change. These two talk sections will help to illustrate how the interface between ecology and evolution might lead to a better understanding of species’ responses to environmental change.

4. Cooperator-defector dynamics in spatially structured environments

Kohmei Kadowaki (Kyoto University)

Cooperation is widespread in nature, although it can easily be destabilized by defectors that reap the benefits of cooperation without paying the costs. Limited dispersal among local populations may favor cooperation via increasing the level of local relatedness, yet this effect may be cancelled by increased competition among kin. Using the bacterium Pseudomonas aeruginosa as a model system and secreted siderophores as public good, I show that the extent to which cooperation is favored directly depends on the dispersal rate, with limited dispersal slowing down the collapse of cooperation. When combining our results from the microbial evolution experiment with empirical dynamic modeling, I demonstrate that limited dispersal reduces the success of bacterial defectors in the evolving bacterium metapopulation through two causal mechanisms: (i) it lowers the ability of defectors to gain benefit from cooperators; and (ii) it hampers de novo defector mutants, which arise from cooperators, to spread through the metapopulation. By deciphering these causalities and the dynamic evolution of the interaction between cooperators and defectors across a gradient of dispersal rates, we obtain a more general understanding of the relationship between dispersal and cooperator-defector dynamics in microbial metapopulations.