Conclusion

The purpose of this project was both to identify areas in most need protection from threats to forest birds and the unique communities that support them, as well as to identify areas in need of expanded monitoring efforts. Avian disease and predation by introduced rodents pose two of the greatest threats to these small populations’ persistence. On a very basic level it is also crucial to determine the distribution of these populations by maintaining adequate coverage of the monitoring area so that changes in distribution can be detected and so that small outlying persistent populations can be appropriately managed.

Using the DEM from the National Elevation Dataset, it was relatively straightforward to calculate zones of increasing disease transmission. The disturbing aspect of this analysis is the proportion of otherwise intact native forest that is already well within the transmission risk zones. These findings reinforce the need to protect habitat in these zones from the compound threats to bird populations from invasive species, both plants and predators. Uniquely, an opportunity presents itself through Kauai’s relatively intact mid-elevation forested plateau to promote resistance to avian malaria in native forest bird species.

Kilpatrick (2005) found that by controlling rat populations at middle elevations, and thus releasing infected birds from a significant cause of mortality, it could be possible to speed the evolutionary development of resistance. The design of rodent control measures to protect and enhance this naturally occurring process will be difficult to persuade local land managers, hunters and the general public to adopt. The ability to optimize the effort and cost involved would likely be facilitated with proper spatial emphasis of management activities.

By using GIS to evaluate current monitoring efforts, the resulting calculations can guide time and resource allocation of surveyors planning to extend monitoring efforts. The areas that were found to be suitable bird habitat that were outside of the current monitoring area should be assessed for potential survey in the near future. Isolated populations of rare and endangered forest birds will be vital to maintaining genetic diversity if, in fact, they have to be actively managed through either captive propagation or translocation. The current distribution is poorly known for most if not all of the native forest birds on Kauai (Camp and Gorreson, 2010). This prioritization may prove helpful in gaining greater resolution on current distributions and future trends.

Overall, these two pieces of information, though relatively straightforward, may prove to be important components in the development of conservation and management of forest bird species on the island of Kauai. Further analysis of terrain may facilitate access to un-surveyed areas, and it may be interesting to see how well the GIS predictions for least-cost path and viewshed based on the DEM compare to ground-truthing by surveyors with large packs and heavy equipment.