Carlson Bradley E, Langkilde Tracy
Department of Biology, Intercollege Graduate Degree Program in Ecology, and Center for Brain, Behavior, and Cognition The Pennsylvania State University University Park PA USA.
Ecol Evol. 2017 Oct 22;7(23):9978-9990. doi: 10.1002/ece3.3511. eCollection 2017 Dec.
Intraspecific phenotypic variation is a significant component of biodiversity. Body size, for example, is variable and critical for structuring communities. We need to understand how homogenous and variably sized populations differ in their ecological responses or effects if we are to have a robust understanding of communities. We manipulated body size variation in consumer (tadpole) populations in mesocosms (both with and without predators), keeping mean size and density of these consumers constant. Size-variable consumer populations exhibited stronger antipredator responses (reduced activity), which had a cascading effect of increasing the biomass of the consumer's resources. Predators foraged less when consumers were variable in size, and this may have mediated the differential effects of predators on the community composition of alternative prey (zooplankton). All trophic levels responded to differences in consumer size variation, demonstrating that intrapopulation phenotypic variability can significantly alter interspecific ecological interactions. Furthermore, we identify a key mechanism (size thresholds for predation risk) that may mediate impacts of size variation in natural communities. Together, our results suggest that phenotypic variability plays a significant role in structuring ecological communities.
种内表型变异是生物多样性的一个重要组成部分。例如，体型是可变的，并且对于构建群落至关重要。如果我们想要对群落有一个全面的了解，就需要明白大小均匀和大小各异的种群在生态响应或影响方面有何不同。我们在中型生态缸（有捕食者和无捕食者两种情况）中操控消费者（蝌蚪）种群的体型变异，同时保持这些消费者的平均体型和密度不变。体型可变的消费者种群表现出更强的反捕食反应（活动减少），这对消费者资源的生物量增加产生了连锁反应。当消费者体型可变时，捕食者的觅食行为减少，这可能介导了捕食者对替代猎物（浮游动物）群落组成的不同影响。所有营养级都对消费者体型变异的差异做出了反应，表明种群内表型变异性能够显著改变种间生态相互作用。此外，我们确定了一个关键机制（捕食风险的体型阈值），它可能介导自然群落中体型变异的影响。总之，我们的结果表明表型变异性在构建生态群落中发挥着重要作用。
