Due to extensive habitat destruction, the Maui ‘Alauahio (Paroreomyza montana) occurs in two known disjunct populations where habitat conditions vary extensively. The primary population occurs in wet and mesic montane native forests dominated by ʻōhiʻa (Metrosideros polymorpha). The second separate population occurs in non-native forests within Polipoli State Recreation Area or Kula Forest Reserve. The Polipoli population lives in dry and mesic forests that were originally koa (Acacia koa.), māmane (Sophora chrysophylla.) and ʻōhiʻa. However, after an experimental forest project in the 1930s it is now dominated by pine (Pinus spp.), eucalyptus (Eucalyptus spp.), ash (Fraxinus spp.), redwood (Sequoia spp.) and cedar (Thuja spp). These birds express differences in their behavior and ecology that have allowed them to exploit these new environments.
In 2013 graduate student Peter Motyka at Northern Arizona University in conjunction with MFBRP began research to investigate the use of non-native forest by native birds will facilitate the ability to evaluate the management of non-native forest for the benefit of native forest bird species. The objectives of this study were to: 1.) Conduct a multi-scale assessment of habitat use by the Maui ‘Alauahio in the Kula Forest Reserve; 2.) Determine the occurrence, distribution, and variable densities of Maui ‘Alauahio in the Kula Forest Reserve; 3.) Investigate potential correlations between bird occurrence and vegetation composition and structure; and 4.) Investigate home range and nesting substrates of Maui ‘Alauahio to determine habitat preference. The project included color-banding and resighting Maui ‘Alauahio, quantification of vegetation structure for foraging habits, variable circular plot point counts for bird densities, and nest searching and monitoring for Maui ‘Alauahio.
The remaining native forests on Maui are small and in order to prevent further extinctions conservation efforts need to consider the value of non-native, fragmented habitats as well. Current conservation efforts are focused on preservation and restoration, but the value of non-native forests for the conservation of native bird species may be of key importance. Many researchers have assessed the effects of forest fragmentation on avian populations but much of this work has focused on patch-level processes such as presence/absence and population turnover rather than demographic processes and there is a paucity of information on how non-native forest fragments are used by native species.
It is important to examine responses of species and ecosystems to landscape modification, and this can help lead to management strategies for natural ecosystem integrity in human-dominated ecosystems. This study advanced both our ability to make practical conservation recommendations as well as our perception of the potential for managing unnaturally altered habitat areas for the benefit and support of native species. The Maui ‘Alauahio is a native passerine under a high threat of extinction.
For more information, see the full thesis here.
This research project was led by Northern Arizona University graduate student Peter Motyka, advised by Dr. Jeffrey Foster.
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