Trait-Based Assessments of Climate-Change Impacts on Interacting Species

Climate change is leading to a fundamental reorganization of ecological communities. Current biodiversity models are mostly limited to the responses of individual species to climate change. Interactions between species, though critically important for species’ performance and survival, are less frequently considered in biodiversity models. Functional traits of plants and animals can be used to quantify their environmental requirements, their probability of interaction in ecological networks, and their movement and dispersal ability. New predictive biodiversity models can be developed which incorporate functional traits and species interactions to better forecast interdependent species responses, novel communities, and eco-evolutionary consequences of climate change. Plant–animal interactions are fundamentally important in ecosystems, but have often been ignored by studies of climate-change impacts on biodiversity. Here, we present a trait-based framework for predicting the responses of interacting plants and animals to climate change. We distinguish three pathways along which climate change can impact interacting species in ecological communities: (i) spatial and temporal mismatches in the occurrence and abundance of species, (ii) the formation of novel interactions and secondary extinctions, and (iii) alterations of the dispersal ability of plants. These pathways are mediated by three kinds of functional traits: response traits, matching traits, and dispersal traits. We propose that incorporating these traits into predictive models will improve assessments of the responses of interacting species to climate change. Plant–animal interactions are fundamentally important in ecosystems, but have often been ignored by studies of climate-change impacts on biodiversity. Here, we present a trait-based framework for predicting the responses of interacting plants and animals to climate change. We distinguish three pathways along which climate change can impact interacting species in ecological communities: (i) spatial and temporal mismatches in the occurrence and abundance of species, (ii) the formation of novel interactions and secondary extinctions, and (iii) alterations of the dispersal ability of plants. These pathways are mediated by three kinds of functional traits: response traits, matching traits, and dispersal traits. We propose that incorporating these traits into predictive models will improve assessments of the responses of interacting species to climate change. the ability of a species to disperse in space (e.g., given by a dispersal kernel that describes a probability distribution of dispersal distances). For plants or other propagules dispersed by animals, the total dispersal kernel results from the specific contributions of each animal species. the entirety of morphological, physiological, or behavioral attributes of an individual that influences how far an organism moves and where and when it is dispersed. In the case of animals, this includes traits, such as body size and shape, resource retention time, and migration mode. a network in which different types of organisms (e.g., plants and animals) are linked by biotic (trophic or nontrophic) interactions, which can be mutually beneficial (as for pollination and seed dispersal) or antagonistic (as for herbivory). attributes of an individual that influence how a species interacts with its abiotic and biotic environment; functional traits can be related to species responses to abiotic conditions (see response traits), to the matching between interaction partners (see matching traits), and to effects on other species or entire communities (e.g., dispersal traits as an example for such effect traits). the formation of novel interactions between species that previously did not interact, usually because these species did not overlap in their spatial or temporal occurrence. Special cases of rewiring are ecological or evolutionary changes in matching traits, which result in novel interactions between species that currently co-occur, but cannot interact. attributes of plants and animals that determine the compatibility between species and the likelihood of an interaction (e.g., related to species’ morphology, physiology, or chemistry). Incompatible matching traits between species can result in forbidden links (i.e., impossible interactions) in novel communities. attributes that affect the response of an individual to its abiotic and biotic environment, for example, the physiological capacity of a plant or animal to survive and reproduce under a certain temperature or physiological processes that regulate a species’ phenology, such as the timing of budburst or insect emergence. extinction events that are triggered secondarily through the loss of essential interaction partners (e.g., the extinction of a pollinator species after the loss of its main food plant). The risk of secondary extinction also depends on the capacity of a species to rewire with new partners. differences in the occurrence or abundance of interacting plant and animal species in space or time under current or projected future conditions (e.g., if a plant is predicted to occur at a place that its main pollinator will never reach or if a plant is predicted to flower at a time when its main pollinator is not active).