Therefore, if monitoring ceases too quickly, an incorrect inference that a crossing structure is ineffective may be drawn. In fact, in some cases monitoring

resources may be more effectively allocated by waiting for a few years after installation of the mitigation measure before starting the ‘after’ monitoring. This may be particularly true when the assessment endpoint is population EPZ015938 purchase viability. Similarly, monitoring a site for too long commits resources after they are needed. Thus, sampling should not begin before an effect is expected to have occurred and should continue long enough to detect lagged and/or transient effects. A worst-case scenario is that the sampling duration is too short to detect a real effect and that future mitigation CBL0137 mouse projects reject the

use of a measure that is, in fact, successful. Step TH-302 in vitro 6: Select appropriate study sites Selection of mitigation sites If a road mitigation evaluation is to assess the effectiveness of multiple wildlife crossing structures along a road or hundreds of mitigation sites at multiple roads, it may be necessary to sample a subset of the available mitigation sites. The method for selecting an appropriate subset of mitigation sites depends on the overall objective of the evaluation. If the objective is to evaluate the extent to which a road mitigation plan is effective for a target species, one should choose a random sample of mitigation sites from the total number of available mitigation sites. Such evaluation only aims to provide insight into the average effectiveness of the road mitigation. If the objective is, however, to evaluate whether wildlife crossing structures potentially mitigate road impacts for the target species, one should choose sites that are most likely to demonstrate statistically significant effects

with comparatively little sampling effort in time. The following criteria provide a framework to select mitigation sites in this context: (1) Select sites where the road effect is known or expected to be high. (2) Select sites where the planned construction of the mitigation measures allows for sufficient time for repeated measurements before construction. (3) Select sites for which sufficient replicate sites can be found. (4) Select sites where multiple mitigation measures are planned for a relatively long section of road as this may allow for phasing or manipulating mitigation in an experimental design (see Step 4 above). A mitigation effect is most likely to be detectable where a significant positive shift in population viability—e.g., estimated through a PVA (see, e.g., van der Grift and Pouwels 2006)—can be expected as a result of the road mitigation measures (Fig. 3). This implies selecting sites where on at least one side of the road the amount of habitat available is sufficient for only a small, non-viable population that needs an influx of animals from the opposite side of the road (Fig.