Methods to test the interactive effects of drought and plant invasion on ecosystem structure and function using complementary common garden and field experiments
Alba, C., NeSmith, J. E., Fahey, C., Angelini, C., & Flory, S. L. (2017). Methods to test the interactive effects of drought and plant invasion on ecosystem structure and function using complementary common garden and field experiments. Ecology and Evolution, 7(5), 1442-1452. PDF.
Summary
Climate change and invasive species are two key drivers threatening ecosystems. Yet, empirical research investigating how these drivers interact remains limited. Furthermore, of the research available, the combined effects of climate change and invasion vary in direction and based on the current biotic and abiotic conditions of the site. Alba et al. (2017) present a standardized experimental approach (i.e., a combination of field experiments and observations) to better understand the complex interactions between plant invasions and changing water availability. They suggest setting up field experiments across moisture gradients (e.g., due to soil texture) and/or experimentally altering the amount of precipitation in common gardens using rain-out shelters. The authors illustrate the utility of this standardized approach by testing the interactive effects of drought and Cogongrass (Imperata cylindrica) invasion. They found no synergistic negative effects of drought and this invader on the native ecosystem, however the invasive grass did offset drought in the common garden experiment. In addition, light availability increased more with invasive removal rather than native removal, suggesting that cogongrass is a strong competitor for light. Continued research implementing standardized experimental methods is needed to best predict the outcome of invasion and climate change on native ecosystems.
Take home points
There is limited research investigating the interaction between climate change and invasive species and its consequence for native ecosystems.
This paper provides a standardized protocol to experimentally test the interaction between plant invasions and climate change by using a combination of common garden experiments and experiments set up along environmental gradients.
Management implications
Interactions between climate change and invasion vary widely in direction, can be taxa specific, and are plagued by uncertainty. Therefore, a coordinated effort between managers and researchers to continue long-term data collection of abiotic (e.g., temperature, CO2, and precipitation) and biotic (e.g., invader abundance and native abundance) conditions on managed lands will enable assessment of interactive impacts of invasives + climate change across environmental gradients.
Keywords
Competitiveness; Impact Study; Experiment; Invasive Plant; Terrestrial Habitat; Imperata cylindrica; Congograss