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Report2017Open access

How species traits influence trophic interaction strength

Wootton, Kate


An organism's traits affect how it interacts with the world and with other species. In a predator-prey interaction both the predator's and prey's traits affect the likelihood that a given predation attempt will be successful. Together multiple predation events determine the strength of the trophic interaction between these two species. A number of traits can be important in determining interaction strength. For trophic interactions, one of the best-studied traits is body size - which has proven so important that a significant portion of interactions within a food web can be predicted from this one trait alone. Beyond body size, other traits, such as prey defenses, mobility, feeding preference, and diet breadth also shape interactions between species. Abiotic conditions shape and alter the relationship between species traits and interaction strength. This impact can be direct, where abiotic conditions change traits or their effectiveness, or indirect, where a species' ability to thrive in that environment - and thus interact with predators or prey - depends on its traits. Species respond to changes in abiotic conditions in different ways, potentially changing interaction strength. For example, temperature affects species at different rates depending on their body size, affecting interaction strength through changes in consumption rate, growth rate etc. Disturbances and changes in climate also affect species unequally, leading to mismatches in relative abundance, phenology or ranges. Such mismatches may lead to novel interactions, or the strengthening or weakening of interactions by altering overlap and encounter rates. Together these trait-mediated interactions shape ecological communities. With a wealth of species interacting at the same time, the sum total of direct and indirect interactions determine community dynamics. Many traits and interactions have been studied, but there are still gaps in our understanding of how these interactions combine. A closer investigation of the mechanisms underpinning the relationship between traits and interaction strength will allow for more efficient quantification of food webs and predictions of how communities will respond to disturbances.


animal behaviour; predator; prey

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Publisher: Institutionen för ekologi, Sveriges lantbruksuniversitet

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