Facilitative and competitive interaction components among New England salt marsh plants

PeerJ

article

John F. Bruno¹  Tatyana A. Rand²  Nancy C. Emery³  Mark D. Bertness⁴ 

[1] Department of Biology, University of North Carolina at Chapel Hill;Northern Plains Agricultural Research Laboratory;Department of Ecology and Evolutionary Biology, University of Colorado at Boulder;Department of Ecology and Evolutionary Biology, Brown University

关键词: Competition;    Facilitation;    Interaction strength;    Salt marsh;   

DOI  :  10.7717/peerj.4049

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Intra- and interspecific interactions can be broken down into facilitative and competitive components. The net interaction between two organisms is simply the sum of these counteracting elements. Disentangling the positive and negative components of species interactions is a critical step in advancing our understanding of how the interaction between organisms shift along physical and biotic gradients. We performed a manipulative field experiment to quantify the positive and negative components of the interactions between a perennial forb, Aster tenuifolius, and three dominant, matrix-forming grasses and rushes in a New England salt marsh. Specifically, we asked whether positive and negative interaction components: (1) are unique or redundant across three matrix-forming species (two grasses; Distichlis spicata and Spartina patens, and one rush; Juncus gerardi), and (2) change across Aster life stages (seedling, juvenile, and adult). For adult Aster the strength of the facilitative component of the matrix-forb interaction was stronger than the competitive component for two of the three matrix species, leading to net positive interactions. There was no statistically significant variation among matrix species in their net or component effects. We found little difference in the effects of J. gerardi on Aster at later life-history stages; interaction component strengths did not differ between juveniles and adults. However, mortality of seedlings in neighbor removal plots was 100%, indicating a particularly strong and critical facilitative effect of matrix species on this forb during the earliest life stages. Overall, our results indicate that matrix forming grasses and rushes have important, yet largely redundant, positive net effects on Aster performance across its life cycle. Studies that untangle various components of interactions and their contingencies are critical to both expanding our basic understanding of community organization, and predicting how natural communities and their component parts will respond to environmental change.

【 授权许可】

CC BY