The following was taken from the 2008-09 Annual Habitat Work Plan, Rhode Island National Wildlife Refuge Complex. For an explanation of the larger context for the following management actions, click on this link to the national Strategic Habitat Conservation/Landscape Conservation Cooperatives.
2008 Management Actions
At all of the beaches that successfully fledged at least one chick, the fledging rate exceeded 50%. Trustom Pond had the highest chick survival rate at 88%, followed by Quonochontaug at 79%, and East Beach in Watch Hill at 69%.
Average least tern productivity on USFWS monitored sites from 1995 to 2008 was 0.34 chicks fledged per pair. Least Tern productivity has been variable from year to year ranging from a 0.63 in 1995 and 2001 to a 0.03 in 1996 and a 0.04 in 2000. Productivity for 2008 was 0.34 overall, with the highest productivity (0.9) documented at Trustom Pond NWR.
American Black Duck Monitoring:Winter waterfowl surveys are conducted in salt marsh habitats at Ninigret, Trustom Pond, Sachuest Point and the John H Chafee refuges. Although surveys have been conducted for over 10 years at three of the refuges, JHC surveys were first conducted in 2004. Surveys are initiated in November of each year and continue bi-weekly through February.
The average number of American Black Ducks (ABDU) observed per survey from 1998 through 2008 on four NWRs in RI.
Salt Marsh Sharp-tailed Sparrow Monitoring:Banding and Nesting success:
In 2008 we were able to secure funding to implement additional monitoring for this species. A total of 118 sparrows were banded with 43 of those captured at Sachuest Point NWR (SPNWR) and 76 at the John H. Chafee NWR (JHC NWR)(Table 6). In addition, all suitable habitat (i.e. high marsh and fringe) was searched throughout the season for nests. Forty-three active nests were located and monitored 2-3 times per week to document success. Overall 74% of the nests successfully fledged at least one chick with a total of 106 chicks fledged (productivity = 2.47 chicks per nest) (Table 6). Nest success was much higher at JHC sites than Sachuest due to extreme nest flooding following rain events during the summer.
Beginning in 2004 we have participated in an investigation of blood Mercury levels in saltmarsh sharp-tailed sparrows on NWRs along the North Atlantic Coast. We have been able to collect and analyze samples during four year at the JHC NWR and during 2004 and 2008 at SPNWR. A total of 74 samples have been analyzed by scientists at the Biodiversity Research Institute, with a total of 20 sparrows sampled during July of 2008 at the two sites (Figure 10).
Occupancy Modeling and Vegetative Data:
The salt marsh habitat at JHC and SP NWRs was divided into 100m grids and surveyed during three complete cycles during the summer to determine occupancy by SSTS. This data will be evaluated with the vegetative data that was collected in each grid to determine if there are patterns in occupied and un-occupied sites, and evaluate detectability. A total of 155 grids were established and surveyed this year. We established 123 grids at JHC and 33 at Sachuest. At JHC, we detected SSTS at least once in 65% of the grids and at Sachuest we detected them in 58%.
A preliminary analysis of this data is shown below and demonstrates the average number of saltmarsh sharp-tailed sparrows observed per survey in each of the five major habitat types (Figure 11). As we further analyze the data we will be able to evaluate selection of habitat as a function of the amount of habitat available in each of these types rather than overall (i.e. since there is much more shrub and high marsh dominated habitat at Sachuest overall, we expect overall numbers to be higher).
Genetics Study – University of New Hampshire:
We have been cooperating with a graduate research project through the University of New Hampshire to evaluate genetics of SSTS from throughout New England which can potentially offer clues to juvenile dispersal. We submitted blood samples for analysis in 2007 and 2008 but have not yet received the results of those analyses.Point counts
Landbird point count surveys were conducted during the breeding season for five consecutive years from 2002-2006 at the Sachuest Point and John H. Chafee NWR marshes. Those surveys were not conducted in 2007 or 2008 as the surveys only effectively document males calling. Since males were detected at all points, but it is only the females that attend to nests and chicks, we still did not have a sense of the relative abundance of nesting females. We are now engaged in more extensive monitoring of nesting females, as discussed previously. Point counts could be useful at scheduled intervals (i.e. every 3-5 years) for long term monitoring to detect possible changes in use of the marsh as a result of changes in habitat suitability.Additional monitoring:
We conducted secretive marsh bird surveys during 2007 and 2008 between April 10 and June 15. We surveyed 7 points at Ninigret, 5 points at Sachuest and 7 points at Chafee. Target species detected at Ninigret include the clapper rail, Virginia rail, least bittern and sora. We detected one king rail at Sachuest and no target species at Chafee. As a result of the survey, however, we did document use by green heron, marsh wren, white-eyed vireo, blue-winged warbler, willow flycatcher and eastern towhee. Also of interest, we frequently get reports of secretive marshbirds documented in Refuge marshes during the fall and into winter. Although formal surveys are not conducted during the non-breeding season, these relatively small areas of marsh appear to provide good quality habitat during fall and winter, particularly for American bittern.
We have contracted with the RINHS to conduct a complete inventory of the distribution and abundance of non-native invasive plants on the John H. Chafee refuge. We hope to have this completed by 2010, at which time we will be able to prioritize habitat restoration activities.