SYMP 7-6
Three's a crowd: Moving beyond single-species invasive research and management

Tuesday, August 11, 2015: 4:10 PM
307, Baltimore Convention Center
Sara Kuebbing, School of Forestry & Environmental Studies, Yale University, New Haven, CT

As the pace of introduction of nonnative species continues to increase, co-occurring invasive plants are becoming the norm rather than the exception. While most research addresses single invaders, most habitats are invaded by multiple species, which may interact to cause non-additive impacts that are currently poorly understood. Scientists and managers, therefore, cannot continue to rely on single-species research to guide management in the coming century. This talk synthesizes the current state of knowledge regarding multiple invaders, and highlights gaps in knowledge, thereby identifying where multi-species invasion research should focus. Specifically, I will address the following three areas of research: 1) interactions among nonnatives; 2) impacts of co-occurring nonnatives; and 3) management of co-invaded habitats.


Ecological theory concerning how plant species interactions can shape community structure and ecosystem function has rarely been directly applied to co-occurring nonnatives. I discuss the current knowledge regarding the frequency in types of interactions among nonnatives and how nonnative plant traits may predict interaction types. I will then suggest how plant interaction theory could inform invasion biology, drawing from well-established hypotheses supported by native plant interaction studies. Correspondingly, a better understanding of nonnative interactions could inform our understanding of when the impacts of co-occurring nonnatives are additive or non-additive, which is pertinent for prioritizing management in co-invaded landscapes. I review studies that have compared the impacts of invasive plants when they occur singly versus when they co-occur. Building upon the current understanding of impacts and interactions between co-occurring species, I will discuss how this knowledge can inform management decisions. I will focus on the prevalence of “invasion treadmills,” a notable phenomenon where the management of a dominant invasive can lead to reinvasion of the site by other nonnatives.