Draft Revised Recovery Plan for the Breeding Range of the Northern Great Plains Piping Plover

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used two independent approaches to evaluate how often habitat was likely available for piping plovers in the Northern Great Plains. Recommendations for measuring habitat: In order to determine how much habitat is necessary to support the population at a stable level into the future, we evaluated how much habitat was available in the various areas in years when reproductive success appeared to be adequate for a stable to increasing population and determined approximately how much habitat was necessary per adult pair(see discussion in the Habitat Needed per Breeding Pair section). Ideally, habitat would be estimated several times throughout the breeding season, in early-to-mid June for peak nest initiation, and again in early July, when most chicks are on the ground. Recognizing that these data can be difficult and expensive to acquire and analyze, the most important data acquisition period is the first two weeks of June, to correspond with the time when habitat is likely most limiting because of the need for chicks to forage on the shoreline near where they hatched. Because both plovers and least terns are monitored in riverine areas, a data acquisition time in the first two weeks of June would provide information suitable for use with both species. Habitat data do not necessarily need to be collected annually, but we encourage entities to collect information on a regular schedule (e.g., every three to five years) so that habitat can be tracked over time and linked to bird numbers. Habitat can be evaluated remotely, using satellite data or other imagery with sufficient ground-truthing to ensure that the remote classifications are sufficiently accurate. We recognize that not all of the habitat that is mapped as having the features associated with piping plover reproduction (bare, sandy/gravelly lightly vegetated sandbars or shorelines along rivers, reservoirs, or alkaline lakes) will be used by piping plovers for a variety of reasons, so the amount of habitat estimated from imagery will be an overestimate (but see Anteau et al. 2014b, 2014c). It is impractical to exclude the unused habitat across the range, but it is likely to be a relatively small subset of the total available habitat, and be roughly proportional to the total amount of habitat available (i.e., when there is a lot of habitat available, there will be more suitable habitat that is not used, when there is less total habitat available, there will be less unused habitat). There is likely some benefit to the birds, i.e., reduced risk of predation and reduced nest density-related issues, when birds are not crowded into limited suitable habitat. Continued study of habitat suitability will improve the definition of`suitable' habitat and will aid in determining the appropriate amounts and densities needed to achieve recovery. On rivers that have more naturalized hydrographs (e.g., the lower Platte and Niobrara Rivers in Nebraska),habitat may be estimable through proxy targets such as stream flow and channel width. These relationships need to be established and tested. 67 VOLUME/:Draft Revised Recovery Plan for the Breeding Range of the Northern Great Plains Piping Plover(Charadrius melodus)