Great news for our Nu‘u Refuge! Through a generous gift of an anonymous donor, we will begin a project in the Nu‘u pond to explore the formation of the pond, the history of the vegetation around the pond and in the Kaupo district and the history of early Hawaiian settlement in the area. We will do this by taking small sediment cores and analyzing them for pollen and charcoal. In other areas of Hawai‘i, such studies have provided a window into the past going back thousands of years.
Islands ecosystems are very fragile, and Hawai‘i is no exception. Over 50% of the birds that inhabited these islands are now extinct, and many of those who remain are holding on by a thread. Since 2007, the land trust has been restoring the ecosystem around the Nu‘u pond to benefit two endangered species, the ae‘o, or Hawaiian Stilt, and the ‘Alae Ke‘oke‘o, or Hawaiian Coot. Both of these waterbirds are found in abundance at the Nu‘u Pond.
Habitat restoration is a complex process of returning an ecosystem to its pre-disturbance structure, function and composition, measured against the productivity, resilience and biodiversity of that system. One of the biggest challenges of habitat restoration lies in our inability to see into the past to know what plants and animals are appropriate to an ecosystem. This is particularly true when many of the plant and animal species are extinct, or no longer exist in that area. This is the problem of finding the appropriate reference ecosystem. Simply put, ecosystems change over time, and until we can understand what plants and animals existed in an ecosystem in the past, we usually have to make educated guesses of what we want the restored system to look like in the future. As you might imagine, it is easy to make mistakes, and a challenge to get it right.
Restoration ecologists often wish there was a window we could look back through to get a glimpse of a site’s history, at different times and under different environmental conditions. In a certain sense, we can do that. Wetlands offer such a window into the past. Pollen and charcoal in particular collect in water, and along with sediment blown in from distant points, accumulate in the water, settle to the bottom and act like an ecological library. Over the past 70 years, incredible advances have been made in pollen and charcoal analysis that when extracted from sediment cores, tell an incredible story of the environmental past.
Recently, an anonymous donor made a gift to the land trust to fund a coring and analysis project in the Nu‘u Pond. Along with several archaeologists experienced in wetlands coring who have offered to volunteer their time and expertise, we look forward to extracting sediment cores from several areas of the Nu‘u Pond. The goal of this project will include several elements, including analysis of the types of plants found in the Kaupo area at different times, and, with luck, some analysis of the relative abundance of these plants in the past. We also hope to find evidence of past fires in the form of charcoal. Charcoal is particularly important since fire is extremely uncommon in Hawaiian ecosystems, and a spike in the amount of charcoal indicates the arrival of humans into the area. Charcoal is also relatively easy to date using Carbon-14 dating methods.
We are extremely grateful to our donors, and to get started on this exciting project. I really look forward to present some of the findings of this study in the near future.
Photos: Courtesy of Haley and Dawn Jernaill