Expanding a Dynamic Model of Species Vulnerability to Climate Change for Hawai‘i and Other Pacific Island Ecosystems

Science Center Objects

Initial studies suggest terrestrial Hawaiian plant species may be vulnerable to climate change. However, these models lack information on species-specific traits that affect ecological and evolutionary responses of species to climate change. Research is needed to refine current vulnerability models and apply these to Pacific Islands outside Hawai‘i.

Hawaiian rainforest, Moloka'i, Hawai'i
Native Hawaiian rainforest on Moloka‘i. Photo: L. Fortini

Overview:

Initial studies suggest terrestrial Hawaiian plant species may be vulnerable to climate change. However, these models lack information on species-specific traits that affect ecological and evolutionary responses of species to climate change. Research is needed to refine current vulnerability models and apply these to Pacific Islands outside Hawai‘i.

As global climate change continues to impact Pacific Islands, the need for local and regional adaptation has made vulnerability assessments (VA) an increasingly useful decision-making tools for biocultural resource managers. A VA can help resource managers prioritize conservation actions and strategically allocate funding, offering a source of information that can guide adaptive management planning and implementation.

As a collaboration among USGS, US Fish & Wildlife Service (USFWS), The Nature Conservancy Hawai‘i (TNCH), Univerisity of Hawai‘i at Hilo (UH Hilo), Hawai‘i Cooperative Studies Unit (HCSU), and US Department of Agriculture Natural Resources Conservation Service (NRCS), we have devised a flexible approach that effectively tailors our VA approach to the Pacific Islands, for which information is often limited and fragmented and large future climate uncertainties exist. The approach is based on a Bayesian Network (BN) model that allows integration of multiple types/sources of information necessary to determine species responses to projected climate shifts (e.g., migration to new compatible climate areas). In a first application of this approach, we have integrated species spatial distribution models with a suite of landscape indicators that attenuate (e.g., distribution of protected areas) or exacerbate (e.g., highly degraded areas) climate change impacts. We have identified vulnerable species as those less likely to exhibit any of the three responses required for a species to persist under climate change: migrate in pace with shifting climate, tolerate changes within the current range, or find micro-climatic refugia within areas generally not suitable in climate by 2100.

However, this first iteration of our approach is an incomplete picture of vulnerability because it does not consider species traits known to contribute to the vulnerability of species to climate change (e.g., reproductive capacity, population numbers, dispersal characteristics, etc.). Without these traits, past assessment results do not consider, among other things, the likelihood of species evolutionary adaptation to a shifting climate, a potentially important response of individual species to climate change.

Previous and existing work does not contain analyses that rigorously define and dynamically update research and monitoring priorities to ensure future efforts tackle the most important remaining uncertainties in species responses to climate change.

Furthermore, the existing work is focused on the Hawaiian Islands, and there is a need to generate a well-documented toolset that can be used in other Pacific Islands and elsewhere.

Project Objectives:

PIERC_Collaborator meeting
Hawai‘i plant vulnerability assessment research team. Photo: L. Fortini
  1. Expand a climate change vulnerability assessment model recently applied to all Hawaiian native plant species to include species traits that can influence ecological and evolutionary responses of species to climate change
  2. Build expanded Bayesian Network-based species vulnerability model to create a robust research and monitoring prioritization tool for improved future predictions of climate impacts on Hawaiian flora
  3. With the completion of these substantial assessment improvements, create an assessment toolset that can be applied to other species groups and other areas across the Pacific Islands and beyond.

While research on climate change impacts has typically focused on uncertainties of climate projections, the uncertainties in the underlying ecological responses to climate shifts are perhaps an even greater challenge to address in Hawai‘i and other Pacific islands. The proposed dynamic research prioritization tool starts an effort to address the biological impacts of climate change on Pacific Island ecosystems. This species vulnerability assessment is possibly the largest in scope for the entire country, with over 1000 species considered and comprising a substantial proportion (319 species) of all threatened and endangered species listed under the endangered species act.

Progress:

Research is ongoing.

Manuscripts highlighting a portion of the reults of this project are available:

Beyond exposure, sensitivity and adaptive capacity: a response based ecological framework to assess species climate change vulnerability (2017) in the journal Climate Change Responses

At a global scale, do climate change threatened species also face a greater number of non-climatic threats? (2017) in the journal Global Ecology and Conservation