A method for evaluating outcomes of restoration when no reference sites exist

Brewer, J.S. and T. Menzel. 2009. A method for evaluating outcomes of restoration when no reference sites exist. Restoration Ecology 17: 4-11

>In this paper, Brewer and Menzel propose an alternative approach, habitat data matrices, to determining the reference condition for a restoration site when no extant reference site exists. They showed its applicability by analyzing a data set from an open oak woodland restoration project in Mississippi. After sampling various plots within their targeted site, they combined the presence-absence data and a species list from similar habitat types to calculate a metric for each species, which would indicate how likely they would occur within a specific habitat. They evaluated restored plots by regressing the change in a species relative abundance and its habitat indicator score. If there was an increase in abundance of species with high scores for their target habitat, they inferred that the restoration was successful.
>The authors definitely present a novel approach to assessing the success of a restoration project; however, it tends to overemphasize the rare species within a habitat, which are usually the hardest to restore. While they presented this technique as a tool when no extant reference condition exists, their case study suggests that managers actually need a lot of data from either historical records or similar extant systems that have different temporal characteristics to be successful. This approach can be very risky because it can potentially be implemented without any knowledge of how the species within the community naturally assembled and could lead to the dominance of weedy or invasive species; however it provides a clear metric to evaluate success (e.g., the increase in abundance of targeted species).

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