At least 59 species of native birds have become extinct in the Hawaiian Islands since humans arrived there some 1000-1300 years ago. Early reports indicate that the endangered Hawaiian Petrel once "darkened the skies", but later declined in numbers until it was nearly extinct by the early 20th century. This study will address: 1) how large the Hawaiian Petrel population was before human arrival, 2) if Hawaiian Petrels on different islands are genetically distinct subpopulations, 3) if the diet and feeding location of Hawaiian Petrels changed over time, and 4) how changes in the population genetics or feeding ecology relate to human activities. These topics can be unmasked by analyzing DNA sequences, stable isotope values, and radiocarbon dates from bones of petrels that died during the past 3000 years - beginning before and continuing after human arrival. The study will also assess whether dramatic declines in numbers of breeding seabirds affected Hawaiian plant communities by reducing the flow of nutrients from ocean to land in the islands.
The effects of humans on island and ocean ecology can be understood through studies like this one. By analyzing modern and ancient bird bones, Hawaii's past is brought to life and offers a baseline for ecological restoration and management. For example, understanding marine nutrient flow could prove important for forest and watershed conservation, and reconstructing change in petrel diets over time can enlighten fisheries management. The project engages several students and captures the interest of young Hawaiians who participate in the fieldwork, and also the interest of the press (e.g. http://the.honoluluadvertiser.com/article/2007/Aug/07/ln/hawaii708070352.html). It will include the development of creative media for the public and K-12 students.
The forebears of modern Polynesians first spread eastward into the Pacific Ocean approximately 3500 years ago and by 800 years ago had colonized virtually every inhabitable island in Oceania. The vast marine ecosystem and islands of the central Pacific were essentially untouched by human ecological impacts until then. It is well known that human impacts in the Pacific caused ecological change to island ecosystems leading to the extinction of hundreds to thousands of bird species and forests. The myriad of islands in the Pacific provide a network of breeding sites to seabirds, which are important carnivores in the marine ecosystem but particularly vulnerable to predation on land. During the Human era in Oceana, paleontological and archaeological records document extirpation of many colonies, predominantly of procellariids, a group of seabirds that includes the Hawaiian Petrel (HAPE). In the Hawaiian Islands, the Hawaiian terrestrial ecosystem was strongly affected by human-induced change. As many as 50 species endemic land birds became extinct following human arrival. A well-known biologist, Munro, quoted native Hawaiians who said HAPE was previously so abundant that it "darkened the skies". HAPE was one of the few species that survived human impacts and this endangered species is available to study today. Yet prior to this NSF award, little was known certain aspects of the biology of HAPE. Other scientists showed that HAPE flies across large expanses of the North Pacific Ocean in search for food (e.g. from Hawaii to the Aleutian Islands sometimes in less than two weeks) and that it spends 6 years entirely at sea before breeding. Yet we did not know what it foraged, what it ate or if there were genetic differences that separated populations of HAPE living on Maui, Lanai, Hawaii or Kauai. Our goals were to learn about these aspects of HAPE so as to assist conservation of HAPE and other Hawaiian seabirds. Working with Hawaiian conservation biologists we obtained feathers and bones from birds that had died (e.g. from cat predation) and used molecular techniques (DNA sequencing and analysis of the stable isotopes of carbon and nitrogen) to assess foraging habits (trophic level and foraging location) and genetic relationships among colonies from different islands. We also obtained bone samples from museums and reconstructed molecular records extending back 3000 years. We found isotopic and genetic differences among modern colonies on the Hawaiian Islands. Isotope data appear to reflect differences in the feeding location of birds originating from colonies on Hawaii, Kauai and Maui and suggest that adults from Kauai feed in one part of the ocean but provision their chicks from a different location. However, Hawaii adults provision their chicks from the same place that they obtain their own food. These differences among colonies identify an important conservation strategy to managers, biologists need to manage colonies on different islands as distinct units. Our study is remarkable. It reveals an unexpected level of genetic structure, and differentiation in foraging habits, within a species that can use a large portion of the North Pacific and provides insight into the causes of speciation in pelagic seabirds. DNA analysis from ancient bones detected no change in the genetic diversity of HAPE over the past 2000 years, even though humans arrived in the islands about 1000 years ago. The ability of the HAPE to maintain genetic diversity despite its population decline might be explained by traits commonly found in seabirds, such as long lives, delayed breeding, and high mobility. Stable isotope data is suggesting a change in HAPE’s foraging habits sometime in the 20th century. Further study is needed to determine whether this shift is adversely affecting the population viability of HAPE and other pelagic seabirds. Our grant was able to support several related spinoff projects involving DNA analyses of other Hawaiian seabirds. These include a comparison of the species limits and divergence times of the Hawaiian and Galapagos petrels, two close sister species that were once considered the same species; a study of a new species of shearwater found in the Hawaiian Islands; and the genetic relationships of an extinct and unique procellariid (Pterodroma jugabilis) from the Hawaiian Islands based on subfossil bone DNA sequences (Welch et al., in preparation). Finally, GIS software will map known and modeled former breeding distributions of Hawaiian seabird species We published or have in review 10 papers and presented our results at numerous meetings, invited talks, and seminars. We helped students learn scientific techniques and how to write successful fellowships including 2 doctoral students, one Masters student and several undergraduates, 2 of which were awarded fellowships to work on this project and the project contributed to 3 differente classes. For more information, you may read the publications below or visit a beautiful web site describing our project (ej.msu.edu/hawaii_2/index.html), and an online report (livescience.com/environment/080815-bts-hawaii-petrels-html).
