Browsing by Author "Price, Jonathan"

Now showing 1 - 3 of 3
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    A landscape-based assessment of climate change vulnerability for all native plants.
    (2016-01-25) Fortini, Lucas; Price, Jonathan; Jacobi, James; Vorsino, Adam; Burgett, Jeff; Brinck, Kevin; Amidon, Fred; Miller, Steve; Gon III, Sam; Koob, Gregory; Paxton, Eben
    In Hawaiʽi and elsewhere, research efforts have focused on two main approaches to determine the potential impacts of climate change on individual species: estimating species vulnerabilities and projecting responses of species to expected changes. We integrated these approaches by defining vulnerability as the inability of species to exhibit any of the responses necessary for persistence under climate change (i.e., tolerate projected changes, endure in microrefugia, or migrate to new climate-compatible areas, but excluding evolutionary adaptation). To operationalize this response-based definition of species vulnerability within a landscape-based analysis, we used current and future climate envelopes for each species to define zones across the landscape: the toleration zone; the microrefugia zone; and the migration zone. Using these response zones we calculated a diverse set of factors related to habitat area, quality, and distribution for each species, including the amount of habitat protection and fragmentation and areas projected to be lost to sea-level rise. We then calculated the probabilities of each species exhibiting these responses using a Bayesian network model and determined the overall climate change vulnerability of each species by using a vulnerability index. As a first iteration of a response-based species vulnerability assessment (VA), our landscape-based analysis effectively integrates species-distribution models into a Bayesian network-based VA that can be updated with improved models and data for more refined analyses in the future. Our results show that the species most vulnerable to climate change also tend to be species of conservation concern due to non-climatic threats (e.g., competition and predation from invasive species, land-use change). Also, many of Hawaiʽi’s taxa that are most vulnerable to climate change share characteristics with species that in the past were found to be at risk of extinction due to non-climatic threats (e.g., archipelago endemism, single-island endemism). Of particular concern are the numerous species that have no compatible-climate areas remaining by the year 2100. Species primarily associated with dry forests have higher vulnerability scores than species from any other habitat type. When examined at taxonomic levels above species, low vulnerabilities are concentrated in families and genera of generalists (e.g., ferns or sedges) and typically associated with mid-elevation wet habitats. Our results replicate findings from other regions that link higher species vulnerability with decreasing range size. This species VA is possibly the largest in scope ever conducted in the United States with over 1000 species considered, 319 of which are listed as endangered or threatened under the U.S. Endangered Species Act, filling a critical knowledge gap for resource managers in the region. The information in this assessment can help prioritize species for special conservation actions, guide the management of conservation areas, inform the selection of research and monitoring priorities, and support adaptive management planning and implementation.
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    Development of Decision Support Systems for Ecosystem Management: A case study on Hawai`i Island
    (2016-05) Kimball, Heather; Price, Jonathan; Tropical Conservation Biology & Environmental Science
    Ecosystem management decisions are inherently complex, requiring the integration of ecological science, economics, policy, cultural values, and stakeholder needs. Decision support systems (DSS) are tools intended to facilitate communication between researchers, land managers and policy makers, with the goal of more informed and holistic decision making at the ecosystem scale. The objective of this thesis was to assess the process of DSS development and generate components of a DSS for an individual land owner to assist in planning ecosystem management. The study area selected to demonstrate this process is 23,000 hectares in the Humu`ula tract on Hawai`i Island administered by the Department of Hawaiian Home Lands. This site was selected because it has an existing land management plan, the `Āina Mauna Legacy Plan, and it represents two main threats to ecosystems in Hawai`i, habitat degradation and non-native plant and animal species invasions. Based on nearly three years of discussions with the stakeholders, the following management goals were identified for the study area: restoration and protection of native plant and bird habitat, gorse (Ulex europaeus) removal, watershed restoration, fire reduction, and most importantly, increased and more consistent funding to support the aforementioned goals. This study is divided into three sections. The first section describes establishing Gross Primary Productivity and Net Primary Productivity parameter estimates for the different land cover classes in the study area in order to project the capacity of the ecosystem to capture carbon under the alternative scenarios. The second section evaluates the use of high resolution imagery to model the current land cover of the study area, particularly the spatial distribution of the invasive shrub gorse. The final section covers a summary, conclusion and the next steps for this project including the parameterization of a state and transition model, used in the Carbon Assessment of Hawai`i, to generate projections and data layers to develop a decision support system for the study area as an appendix.
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    ESTIMATING AND APPLYING BIOLOGICAL PARAMETERS TO ENHANCE MANAGEMENT OF RAUVOLFIA VOMITORIA AN INVASIVE TREE IN NORTH KOHALA, HAWAIʻI
    (2017-06) Sullivan, Timothy Olson; Price, Jonathan; Tropical Conservation Biology & Environmental Science
    Introduced tree species can cause environmental harm through invasive traits like fast growth rates, long-term seed longevity, and long-distance seed dispersal. I estimated these rates for Rauvolfia vomitoria, a tree native to tropical Africa, which was introduced to Hawaii Island in the 1950’s. I then compared these rates to other local trees species, both native and invasive, in order to understand R. vomitoria’s relative invasive risk. It appears to be slow growing at ~1.4mm DBH growth annually, but its seeds can survive over 3 years and can be dispersed up to 1km. Managers have concluded R. vomitoria warrants control, and have decided to contain the invasion. Based on my estimates for growth and dispersal, I calculated the cost for a number of containment scenarios, which ranged from $36,000-$88,000 annually. Given that average annual funding for R. vomitoria control is ~$35,000, managers may need to request more funding or change management-tactics.