Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822
Performing Department
Natural Resources & Environmental Management
Non Technical Summary
The Hawaiian Islands house some of the rarest and most unique bird species in the world and these endemic species are integral to the biological and cultural heritage of the Hawaiian Islands and their people. Unfortunately, many of these species are highly endangered or already extinct. Although 107 endemic land bird species were present in Hawai'i prior to human colonization, only about 6.5% of these are extant and face no immediate threats of extinction. Of the 71 endemic species or subspecies persisting after western contact (ca. 1778), 51 are listed as endangered or more imperiled, with 43 of these on the brink of extinction (i.e. critically endangered, extinct in the wild, or possibly extinct) or already extinct. Nearly every species among these 43 is a forest bird. However, despite these great threats and relatively large research expenditures directed at saving endemic forest birds, some of the most basic science necessary for understanding species of concern has never been done. For instance, population models and population viability analyses (PVA) have not been conducted for 66% of Hawai'i's endangered avifauna, representing a critical gap in knowledge. This lack of knowledge is problematic, given that population viability is one of the criteria used for down listing (or de-listing) a species and that the draft recovery plan for Hawaiian Forest birds ranked PVA as an action necessary to prevent a significant decline in the population. In order to accurately assess the viability of these forest bird species in the face of a changing climate, invasive species, and habitat alteration, and to provide the basis for conservation and management of these critical species, population models and PVAs are urgently needed. Hence, the overarching goal of this research is to model native Hawaiian forest bird populations under current and potential future management scenarios in order to determine their potential efficacy in aiding in the management.
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Goals / Objectives
The overarching goal of this research is to model native Hawaiian forest bird populations under current and potential future management scenarios in order to determine their potential efficacy in aiding in the management. To address this goal, the objectives of the research are to: 1) create and evaluate population viability models of individual forest bird species; 2) develop metapopulation models of forest birds; and, 3) evaluate both types of models under different climate change scenarios and management options.
Project Methods
Hawaii forest bird demographic data, collected by such groups as the Forest Bird Project Recovery Projects for each island, and existing published demographic information (Woodworth and Pratt 2009) and the Birds of North America will be used as the basis for modeling and development of model parameters. Using a selection of well established PVA software packages (e.g., Vortex, RAMAS, GAPPS and/or INMAT) and, if necessary, a matrix-oriented programming environment such as Matlab or R, PVA models will be constructed using the demographic parameters of adult and juvenile mortality, life span, nest success, age at first reproduction, and length of reproductive life. Prior to modeling, available data will be analyzed to estimate parameters, including carrying capacity and stable age distributions, in addition to calculating ranges and variability within the demographic parameters. Each model will be simulated 1000 times (Owen-Smith 2007), measuring the probability of the species persisting at 50, 100 and 1000 years. Models will use initial population sizes ranging based upon current or published estimates. Once the basic PVAs are constructed, the effects of predation on juvenile and adult mortality, as well as changes in mortality due to predator control will be estimated. Next, models of the potential impact of increased malarial infection due to climate change will be carried out via manipulating the adult mortality, as well as a potential decrease in the incidence of malaria in the advent of disease resistance. As appropriate to individual species, the third component of the models will be to consider establishment of several subpopulations to investigate metapopulation dynamics, and the effects of supplementing the extant population with captive bred individuals. Models with interactions between parameters and management scenarios will be run as well. Currently available data will be used to make accurate estimates and to perform sensitivity analysis to understand how data errors or variations affect model outcomes (Akçakaya and Sjögren-Gulve 2000). Once valid models have been run and validated in each of the PVA software programs, the results will be compared between programs in order to develop the most rigorous and realistic model possible. Models will be constructed on individual species basis. One use of the completed models will be to evaluate the possibility of translocations of forest birds to other forest systems. Translocation is of interest given that as the climate warms and mosquitos potentially penetrate malarial free zones, potentially increasing the malaria threat, and invasive species alter the food network on which the species relies, the persistence of forest birds in their relicts of forest becomes more precarious. Furthermore, as evidenced after the 1982 and 1992 hurricanes 'Iwa and 'Iniki, in which five of the six endangered species in the Alaka'i Swamp on Kauai went extinct, small populations existing only in one place, are extremely vulnerable to catastrophic events. Modeling approaches can be of great use in these situations. In fact, this method has previously helped managers of Hawaiian endangered species make tough conservation decisions. For instance, the Nihoa Millerbird PVA (Morin and Conant 1998) was an important factor which prompted the US Fish and Wildlife Service to undertake the recent, and so far successful, translocation of millerbirds from Nihoa to Laysan, an atoll from which millerbirds have been absent for over 100 years. This translocation was done in an effort to create two widely-separate, independent populations of the species in order to reduce the chances that catastrophic disturbance events such as hurricanes or introduction of invasive predators will extirpate the species, after the Morin and Conant's PVA highlighted the species vulnerability to these events. Along these same lines, as appropriate to individual species, models will be developed of potential outcomes of translocating individuals of a species to another population and attempts made to identify the optimal levels of effort and support necessary to successfully create the new population. To accomplish this assessment, key habitat data (e.g., land cover, precipitation, elevation) will be integrated into a niche/species distribution model framework to identify potential sites for population establishment.