Evaluation of red-cockaded woodpecker habitat using a red-cockaded woodpecker Foraging Matrix Application.

摘要

The red-cockaded woodpecker (Picoides borealis) is a listed endangered species, endemic in the southeastern United States. It is a cooperatively breeding species preferring to live in an open, mature and old growth pine ecosystem. The restoration and management of red-cockaded woodpecker habitat is a difficult task within both public and private land. Forest management practices may have adverse effect on nesting and foraging habitat. To delist the red-cockaded woodpecker from the endangered species list, the U.S. Fish and Wildlife Service developed the 2003 Recovery Plan. The foraging matrix was developed to produce an index or scoring system to classify habitat based on criteria of the Recovery Plan. The foraging matrix scores are based on twelve criteria and four habitat criteria at the partition level. The RCW Foraging Matrix Application (FMA) is an automation of the forage matrix in GIS and is being used to evaluate the impact of various forest management practices on RCW habitat. In this study, the GIS foraging matrix was applied to 18-year (1989-2007) forest inventory and cavity tree position data on Hobcaw Barony. Stand and partition scores were developed for each RCW cluster for each of these 18 years. Historical RCW data included the number, position, and activity of all cavity trees for the 18-year period and the locations of all nests from 1994 through 2007. The number of clusters was determined by the method developed by Harlow et al. (1983) and those circles were used to locate individual clusters. Of 36 clusters located in this way from 1994-2007, 31 were found with at least one nest.;Stand scores ranged from 1-4.3 (1-5 possible range) and showed little year-to-year variation. Stand score is heavily weighted to the number and the basal area of large pines, which were not harvested during the period. Only mortality associated with Hurricane Hugo produced a noticeable change in stand scores. There was a qualitative correspondence between stand scores over 3 and success of RCW clusters as measured by persistence or rate of nesting.;Scores at the partition level only varied from 1-2.2 (1-5 possible range). Yearly average partition scores varied from 1.52-2.05 and reached the minimum when the number of clusters was the greatest, while they reached the maximum when the number of clusters was the least. In addition, partition scores rose from 1998-2004 while the numbers of both clusters and nests declined most steeply. Partition score also did not relate to nesting success, with clusters scoring minimum (1.0) and maximum (2.2) each nesting 13 of the 14 years.;The failure of the partition score to be correlated with any indicator of RCW success reveals flaws in the method of calculation of this score. The score is weighted heavily to the area of Good Quality Foraging Habitat, defined as stands that scored 5 (all 12 criteria perfectly met). No stand on Hobcaw met that score, and the partition score was unaffected by the scores of any stand within the partition. The other parameters also give higher scores based on partition area. Since RCW tend to have smaller home ranges in very good habitat an indicator based on area will tend to decline as the habitat improves.;Keywords: endangered species, foraging habitat, foraging matrix application, recovery plan.