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Although climate change is predicted to place mountain-top and other narrowly endemic species at severe risk of extinction, the ecological processes involved in such extinctions are still poorly resolved. In addition, much of this biodiversity loss will likely go unobserved, and therefore largely unappreciated. The Haleakalā silversword is restricted to a single volcano summit in Hawai‘i, but is a highly charismatic giant rosette plant that is viewed by 1–2 million visitors annually. We link detailed local climate data to a lengthy demographic record, and combine both with a population-wide assessment of recent plant mortality and recruitment, to show that after decades of strong recovery following successful management,...
Transmission of avian malaria in the Hawaiian Islands varies across altitudinal gradients and is greatest at elevations below 1500 m where both temperature and moisture are favorable for the sole mosquito vector, Culex quinquefasciatus, and extrinsic sporogonic development of the parasite, Plasmodium relictum. Potential consequences of global warming on this system have been recognized for over a decade with concerns that increases in mean temperatures could lead to expansion of malaria into habitats where cool temperatures currently limit transmission to highly susceptible endemic forest birds. Recent declines in two endangered species on the island of Kaua’i, the ‘Akikiki (Oreomystis bairdi) and ‘Akeke’e (Loxops...
Hawaiian forest birds serve as an ideal group to explore the extent of climate change impacts on at-risk species. Avian malaria constrains many remaining Hawaiian forest bird species to high elevations where temperatures are too cool for malaria’s life cycle and its principal mosquito vector. The impact of climate change on Hawaiian forest birds has been a recent focus of Hawaiian conservation biology, and has centered on the links between climate and avian malaria. To elucidate the differential impacts of projected climate shifts on species with known varying niches, disease resistance and tolerance, we use a comprehensive database of species sightings, regional climate projections and ensemble distribution models...
Publication titled “​Statistical downscaling of rainfall changes in Hawai‘i based on the CMIP5 global model projections”
Climate change is anticipated to affect freshwater resources, but baseline data on the functioning of tropical watersheds is lacking, limiting efforts that seek to predict how watershed processes, water supply, and streamflow respond to anticipated changes in climate and vegetation change, and to management. To address this data gap, we applied the distributed hydrology soil vegetation model (DHSVM) across 88 watersheds spanning a highly constrained, 4500 mm mean annual rainfall (MAR) gradient on Hawai‘i Island to quantify stream flow at 3-h time-steps for eight years in response to the independent and interactive effects of (1) large observed decrease in MAR; (2) projected warming and altered precipitation; and...
Since the beginning of the industrial revolution, the concentration of atmospheric CO2 has been rising due to the burning of fossil fuels. increased absorption of this CO2 by the oceans is lowering the seawater pH and aragonite saturation state (Ωar). This process is known as ocean acidification (OA). numerous studies have shown a direct correlation between declining ocean pH, declining Ωar, and declining coral growth, but the mechanism is not understood. Various experiments designed to evaluate the relative importance of pH, CO3 2–, Ωar, HCO3 –, aqueous CO2, total alkalinity, and total inorganic carbon (Ct) to coral calcification have led to opposing conclusions. A reanalysis of existing data suggests that the...
For many species the threats of climate change occur in a context of multiple existing threats. Given the current focus of global change ecology in identifying and understanding species vulnerable to climate change, we performed a global analysis to characterize the multi-threat context for species threatened by climate change. Utilizing 30,053 species from the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species, we sought to evaluate if species threatened by climate change are more likely threatened by a greater number of non-climatic threats than species not threatened by climate change. Our results show that species threatened by climate change are generally impacted by 21%...
Montane plant communities throughout the world have responded to changes in precipitation and temperature regimes by shifting ranges upward in elevation. Continued warmer, drier climate conditions have been documented and are projected to increase in high-elevation areas in Hawai‘i, consistent with climate change effects reported in other environments throughout the world. Organisms that cannot disperse or adapt biologically to projected climate scenarios in situ may decrease in distributional range and abundance over time. Restoration efforts will need to accommodate future climate change and account for the interactive effects of existing invasive species to ensure long-term persistence. As part of a larger, ongoing...
Determination of carbon isotope (δ13C) values of tree-ring tissue is a well-established method to reconstruct past climate variability at annual resolution, but such records are limited in tropical latitudes due to the lack of well-defined annual growth bands. Recent work has demonstrated the potential for high-resolution, intra-ring δ13C records to help define ring boundaries in tropical environments and provide additional climate information at sub-annual resolution. Here we present a high-resolution, intra-ring carbon isotope (δ13C) record of the Hawaiian endemic species Sophora chrysophylla(also known as “māmane”) in order to assess the ability to extract seasonal climate information from these drought tolerant...
Global sea-level rise (SLR) is projected to accelerate over the next century, with research indicating that global mean sea level may rise 18–48 cm by 2050, and 50–140 cm by 2100. Decision-makers, faced with the problem of adapting to SLR, utilize elevation data to identify assets that are vulnerable to inundation. This paper reviews techniques and challenges stemming from the use of Light Detection and Ranging (LiDAR) digital elevation models (DEMs) in support of SLR decision-making. A significant shortcoming in the methodology is the lack of comprehensive standards for estimating LiDAR error, which causes inconsistent and sometimes misleading calculations of uncertainty. Workers typically aim to reduce uncertainty...
As the impacts of global climate change on species are increasingly evident, there is a clear need to adapt conservation efforts worldwide. Species vulnerability assessments (VAs) are increasingly used to summarize all relevant information to determine a species’ potential vulnerability to climate change and are frequently the first step in informing climate adaptation efforts. VAs commonly integrate multiple sources of information by utilizing a framework that distinguishes factors relevant to species exposure, sensitivity, and adaptive capacity. However, this framework was originally developed for human systems, and its use to evaluate species vulnerability has serious practical and theoretical limitations. By...
A comparison of the equations for photosynthesis and calcification in reef corals suggests that the two processes compete for available inorganic carbon; yet reef corals exhibit simultaneous high rates of photosynthesis and calcification during daylight hours. Also, the extreme metabolic activity observed in corals at high irradiance requires a large net efflux of protons at sites of rapid calcification and respiration. Corals have resolved these problems through development of morphologies that separate the zone of rapid calcification (ZC) from the zone of rapid photosynthesis (ZP), with the fixed-carbon energy supply from the ZP being rapidly translocated to the ZC. Translocation of photosynthate from the ZP serves...
Projections of climate change impacts on coral reefs produced at the coarse resolution (~1°) of Global Climate Models (GCMs) have informed debate but have not helped target local management actions. Here, projections of the onset of annual coral bleaching conditions in the Caribbean under Representative Concentration Pathway (RCP) 8.5 are produced using an ensemble of 33 Coupled Model Intercomparison Project phase-5 models and via dynamical and statistical downscaling. A high-resolution (~11 km) regional ocean model (MOM4.1) is used for the dynamical downscaling. For statistical downscaling, sea surface temperature (SST) means and annual cycles in all the GCMs are replaced with observed data from the ~4-km NOAA...
Local and traditional ecological knowledge (TEK) systems are thought to be particularly valuable for fostering adaptation and resilience to environmental and climate change. This paper investigates the role of TEK in adaptation to social–ecological change at the community level. It is unique because it takes a longitudinal perspective and draws on historical and contemporary data. We focus on a case study from Hawai‘i where TEK, cultural identity, and their relationships to environmental stewardship are locally seen as the basis for social resilience. We describe how coping strategies and indicators of social resilience have changed over time; the role of TEK in resilience; and the implications for climate change...
Waves are the dominant influence on coastal morphology and ecosystem structure of tropical Pacific islands. Wave heights, periods, and directions for the 21st century were projected using near-surface wind fields from four atmosphere–ocean coupled global climate models (GCM) under representative concentration pathways (RCP) 4.5 and 8.5. GCM-derived wind fields forced the global WAVEWATCH-III wave model to generate hourly time series of bulk wave parameters around 25 islands in the mid to western tropical Pacific Ocean for historical (1976–2005), mid-century, and end-century time periods for the December–February and June–August seasons. The December–February regional wave climate is dominated by strong winds and...
Climate-change impacts on coral reefs are expected to include temperature-induced spatially extensive bleaching events1. Bleaching causes mortality when temperature stress persists but exposure to bleaching conditions is not expected to be spatially uniform at the regional or global scale2. Here we show the first maps of global projections of bleaching conditions based on ensembles of IPCC AR5 (ref. 3) models forced with the new Representative Concentration Pathways4 (RCPs). For the three RCPs with larger CO2 emissions (RCP 4.5, 6.0 and 8.5) the onset of annual bleaching conditions is associated with ∼ 510 ppm CO2 equivalent; the median year of all locations is 2040 for the fossil-fuel aggressive RCP 8.5. Spatial...
Anticipating potential shifts in plant communities has been a major challenge in climate change ecology. In Hawaiʻi, where conservation efforts tend to be habitat focused, the lack of projections of vegetation shifts under future climate is a major knowledge gap for developing management actions aimed at climate change mitigation and adaptation. • As a first approximation of such changes, we have modeled potential shifts of terrestrial vegetation across the Hawaiian landscape between now and the end of this century. Our approach relies on modeling the relation between current climate and the distribution of broad, climatically determined moisture zones (for example, dry, mesic, and wet areas) that form the basis...
BackgroundDetailed assessments of species responses to climate change are uncommon, owing to the limited nature of most ecological and local climate data sets. Exceptions, such as the case of the Haleakalā silversword, can provide important insights into the complexity of biological responses to changing climate conditions. We present a time series of decadal population censuses, combined with a pair of early population projections, which together span the past 80 years of demographic history for this alpine plant.ResultsThe time series suggests a strong population recovery from the 1930s through the 1980s, likely owing at least in part to management actions taken on its behalf. In contrast, the population is estimated...
Publication titled “Projection of changes in the frequency of heavy rain events over Hawaii based on leading Pacific climate modes”
Non-native species invasions, growing human populations, and climate change are central ecological concerns in tropical island communities. The combination of these threats have led to losses of native biota, altered hydrological and ecosystem processes, and reduced ecosystem services. These threats pose complex problems to often underfunded management entities. We developed a watershed decision support tool (WDST) for the windward coast of Hawai‘i Island aimed at prioritizing catchments for invasive species removal and native forest protection from non-native species invasions. Using the Ecosystem Management Decision Support (EMDS) system, we integrated spatial data from four sources: (i) native and invasive species...