Mean grass cover in grass removal, seed addition experiment, Hakalau Forest NWR

Publication Date

2021-01-05

Start Date

2017-08-01

Yelenik, S.G., Rehm, E.M., and D'Antonio, C.M., 2021, Hakalau Forest NWR seed rain, seedling, and plant data for 2017-2019: U.S. Geological Survey data release, https://doi.org/10.5066/P9MY5240.

Alternative stable equilibrium (ASE) theory hypothesizes that a system can exist as multiple stable-states under the same environmental conditions. The current state is determined by priority effects and is non-transitory due to the positive feedbacks between the community and the environment. Only when certain thresholds are met do systems experience phase shifts from one stable-state to an alternative. Understanding where these thresholds are is important for restoration and management because it helps managers predict the level of resources needed to push an ecosystem from a degraded state to a more desired condition. We addressed thresholds to native plant germination and survival by experimentally manipulating seed rain and exotic grass cover, while simultaneously monitoring background rates of these variables. As a part of this we implemented an experiment where we varied the exotic grass cover and seed rain ourselves, to better understand where these thresholds lie, and if it is realistic to think natural forest regeneration will happen naturally or management will be needed.

• Pacific Island Ecosystems Research Center

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