Creekside Center for Earth Observation

Menlo Park, CA, United States

Creekside Center for Earth Observation

Menlo Park, CA, United States

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Tran T.J.,Western Washington University | Bruening J.M.,Western Washington University | Bunn A.G.,Western Washington University | Salzer M.W.,University of Arizona | Weiss S.B.,Creekside Center for Earth Observation
Environmental Research Letters | Year: 2017

Tree rings have long been used to make inferences about the environmental factors that influence tree growth. Great Basin bristlecone pine is a long-lived species and valuable dendroclimatic resource, but often with mixed growth signals; in many cases, not all trees at one location are limited by the same environmental variable. Past work has identified an elevational threshold below the upper treeline above which trees are limited by temperature, and below which trees tend to be moisture limited. This study identifies a similar threshold in terms of temperature instead of elevation through fine-scale topoclimatic modeling, which uses a suite of topographic and temperature-sensor data to predict temperatures across landscapes. We sampled trees near the upper limit of growth at four high-elevation locations in the Great Basin region, USA, and used cluster analysis to find dual-signal patterns in radial growth. We observed dual-signal patterns in ring widths at two of those sites, with the signals mimicking temperature and precipitation patterns. Trees in temperature-sensitive clusters grew in colder areas, while moisture-sensitive cluster trees grew in warmer areas. We found thresholds between temperature- and moisture-sensitivity ranging from 7.4°C to 8°C growing season mean temperature. Our findings allow for a better physiological understanding of bristlecone pine growth, and seek to improve the accuracy of climate reconstructions. © 2017 IOP Publishing Ltd.


Bruening J.M.,Western Washington University | Tran T.J.,Western Washington University | Bunn A.G.,Western Washington University | Weiss S.B.,Creekside Center for Earth Observation | Salzer M.W.,University of Arizona
Environmental Research Letters | Year: 2017

Great Basin bristlecone pine (Pinus longaeva) and foxtail pine (Pinus balfouriana) are valuable paleoclimate resources due to their longevity and climatic sensitivity of their annually-resolved rings. Treeline research has shown that growing season temperatures limit tree growth at and just below the upper treeline. In the Great Basin, the presence of precisely dated remnant wood above modern treeline shows that the treeline ecotone shifts at centennial timescales tracking long-term changes in climate; in some areas during the Holocene climatic optimum treeline was 100 meters higher than at present. Regional treeline position models built exclusively from climate data may identify characteristics specific to Great Basin treelines and inform future physiological studies, providing a measure of climate sensitivity specific to bristlecone and foxtail pine treelines. This study implements a topoclimatic analysis - using topographic variables to explain patterns in surface temperatures across diverse mountainous terrain - to model the treeline position of three semi-arid bristlecone and/or foxtail pine treelines in the Great Basin as a function of growing season length and mean temperature calculated from in situ measurements. Results indicate: (1) the treeline sites used in this study are similar to other treelines globally, and require a growing season length of between 147-153 days and average temperature ranging from 5.5°C-7.2°C, (2) site-specific treeline position models may be improved through topoclimatic analysis and (3) treeline position in the Great Basin is likely out of equilibrium with the current climate, indicating a possible future upslope shift in treeline position. © 2017 IOP Publishing Ltd.


Heller N.E.,Dwight Center for Conservation Science at Pepperwood Preserve | Heller N.E.,Duke University | Kreitler J.,U.S. Geological Survey | Ackerly D.D.,University of California at Berkeley | And 6 more authors.
Ecosphere | Year: 2015

Climate change is raising challenging concerns for systematic conservation planning. Are methods based on the current spatial patterns of biodiversity effective given long-term climate change? Some conservation scientists argue that planning should focus on protecting the abiotic diversity in the landscape, which drives patterns of biological diversity, rather than focusing on the distribution of focal species, which shift in response to climate change. Climate is one important abiotic driver of biodiversity patterns, as different climates host different biological communities and genetic pools. We propose conservation networks that capture the full range of climatic diversity in a region will improve the resilience of biotic communities to climate change compared to networks that do not. In this study we used historical and future hydro-climate projections from the high resolution Basin Characterization Model to explore the utility of directly targeting climatic diversity in planning. Using the spatial planning tool, Marxan, we designed conservation networks to capture the diversity of climate types, at the regional and sub-regional scale, and compared them to networks we designed to capture the diversity of vegetation types. By focusing on the Conservation Lands Network (CLN) of the San Francisco Bay Area as a realworld case study, we compared the potential resilience of networks by examining two factors: the range of climate space captured, and climatic stability to 18 future climates, reflecting different emission scenarios and global climate models. We found that the climate-based network planned at the sub-regional scale captured a greater range of climate space and showed higher climatic stability than the vegetation and regional based-networks. At the same time, differences among network scenarios are small relative to the variance in climate stability across global climate models. Across different projected futures, topographically heterogeneous areas consistently show greater climate stability than homogenous areas. The analysis suggests that utilizing high-resolution climate and hydrological data in conservation planning improves the likely resilience of biodiversity to climate change. We used these analyses to suggest new conservation priorities for the San Francisco Bay Area. © 2015 Heller et al.


Chornesky E.A.,Carmel | Beier P.,Northern Arizona University | Davis F.W.,National Center for Ecological Analysis And Synthesis | Flint L.E.,U.S. Geological Survey | And 9 more authors.
BioScience | Year: 2015

Significant efforts are underway to translate improved understanding of how climate change is altering ecosystems into practical actions for sustaining ecosystem functions and benefits. We explore this transition in California, where adaptation and mitigation are advancing relatively rapidly, through four case studies that span large spatial domains and encompass diverse ecological systems, institutions, ownerships, and policies. The case studies demonstrate the context specificity of societal efforts to adapt ecosystems to climate change and involve applications of diverse scientific tools (e.g., scenario analyses, downscaled climate projections, ecological and connectivity models) tailored to specific planning and management situations (alternative energy siting, wetland management, rangeland management, open space planning). They illustrate how existing institutional and policy frameworks provide numerous opportunities to advance adaptation related to ecosystems and suggest that progress is likely to be greatest when scientific knowledge is integrated into collective planning and when supportive policies and financing enable action. © The Author(s) 2015. Published by Oxford University Press on behalf of the American Institute of Biological Sciences.


Lawler J.J.,University of Washington | Ackerly D.D.,University of California at Berkeley | Albano C.M.,University of California at Davis | Anderson M.G.,The Nature Conservancy | And 6 more authors.
Conservation Biology | Year: 2015

Most conservation planning to date has focused on protecting today's biodiversity with the assumption that it will be tomorrow's biodiversity. However, modern climate change has already resulted in distributional shifts of some species and is projected to result in many more shifts in the coming decades. As species redistribute and biotic communities reorganize, conservation plans based on current patterns of biodiversity may fail to adequately protect species in the future. One approach for addressing this issue is to focus on conserving a range of abiotic conditions in the conservation-planning process. By doing so, it may be possible to conserve an abiotically diverse "stage" upon which evolution will play out and support many actors (biodiversity). We reviewed the fundamental underpinnings of the concept of conserving the abiotic stage, starting with the early observations of von Humboldt, who mapped the concordance of abiotic conditions and vegetation, and progressing to the concept of the ecological niche. We discuss challenges posed by issues of spatial and temporal scale, the role of biotic drivers of species distributions, and latitudinal and topographic variation in relationships between climate and landform. For example, abiotic conditions are not static, but change through time-albeit at different and often relatively slow rates. In some places, biotic interactions play a substantial role in structuring patterns of biodiversity, meaning that patterns of biodiversity may be less tightly linked to the abiotic stage. Furthermore, abiotic drivers of biodiversity can change with latitude and topographic position, meaning that the abiotic stage may need to be defined differently in different places. We conclude that protecting a diversity of abiotic conditions will likely best conserve biodiversity into the future in places where abiotic drivers of species distributions are strong relative to biotic drivers, where the diversity of abiotic settings will be conserved through time, and where connectivity allows for movement among areas providing different abiotic conditions. © 2015 Society for Conservation Biology.


PubMed | The Nature Conservancy, University of Washington, James Cook University, University of Montana and 6 more.
Type: Journal Article | Journal: Conservation biology : the journal of the Society for Conservation Biology | Year: 2015

Most conservation planning to date has focused on protecting todays biodiversity with the assumption that it will be tomorrows biodiversity. However, modern climate change has already resulted in distributional shifts of some species and is projected to result in many more shifts in the coming decades. As species redistribute and biotic communities reorganize, conservation plans based on current patterns of biodiversity may fail to adequately protect species in the future. One approach for addressing this issue is to focus on conserving a range of abiotic conditions in the conservation-planning process. By doing so, it may be possible to conserve an abiotically diverse stage upon which evolution will play out and support many actors (biodiversity). We reviewed the fundamental underpinnings of the concept of conserving the abiotic stage, starting with the early observations of von Humboldt, who mapped the concordance of abiotic conditions and vegetation, and progressing to the concept of the ecological niche. We discuss challenges posed by issues of spatial and temporal scale, the role of biotic drivers of species distributions, and latitudinal and topographic variation in relationships between climate and landform. For example, abiotic conditions are not static, but change through time-albeit at different and often relatively slow rates. In some places, biotic interactions play a substantial role in structuring patterns of biodiversity, meaning that patterns of biodiversity may be less tightly linked to the abiotic stage. Furthermore, abiotic drivers of biodiversity can change with latitude and topographic position, meaning that the abiotic stage may need to be defined differently in different places. We conclude that protecting a diversity of abiotic conditions will likely best conserve biodiversity into the future in places where abiotic drivers of species distributions are strong relative to biotic drivers, where the diversity of abiotic settings will be conserved through time, and where connectivity allows for movement among areas providing different abiotic conditions.


Hernandez D.L.,Carleton College | Vallano D.M.,University of California at Santa Cruz | Zavaleta E.S.,University of California at Santa Cruz | Tzankova Z.,University of California at Santa Cruz | And 4 more authors.
BioScience | Year: 2016

Nitrogen (N) pollution is increasingly recognized as a threat to biodiversity. However, our understanding of how N is affecting vulnerable species across taxa and broad spatial scales is limited. We surveyed approximately 1400 species in the continental United States listed as candidate, threatened, or endangered under the US Endangered Species Act (ESA) to assess the extent of recognized N-pollution effects on biodiversity in both terrestrial and aquatic ecosystems. We found 78 federally listed species recognized as affected by N pollution. To illustrate the complexity of tracing N impacts on listed species, we describe an interdisciplinary case study that addressed the threat of N pollution to California Bay Area serpentine grasslands. We demonstrate that N pollution has affected threatened species via multiple pathways and argue that existing legal and policy regulations can be applied to address the biodiversity consequences of N pollution in conjunction with scientific evidence tracing N impact pathways. © 2016 The Author(s) 2016. Published by Oxford University Press on behalf of the American Institute of Biological Sciences. All rights reserved.


Ackerly D.D.,University of California at Berkeley | Loarie S.R.,Carnegie Institution for Science | Cornwell W.K.,University of California at Berkeley | Weiss S.B.,Creekside Center for Earth Observation | And 4 more authors.
Diversity and Distributions | Year: 2010

Aim: Climate change poses significant threats to biodiversity, including impacts on species distributions, abundance and ecological interactions. At a landscape scale, these impacts, and biotic responses such as adaptation and migration, will be mediated by spatial heterogeneity in climate and climate change. We examine several aspects of the geography of climate change and their significance for biodiversity conservation. Location: California and Nevada, USA. Methods: Using current climate surfaces (PRISM) and two scenarios of future climate (A1b, 2070-2099, warmer-drier and warmer-wetter), we mapped disappearing, declining, expanding and novel climates, and the velocity and direction of climate change in California and Nevada. We also examined fine-scale spatial heterogeneity in protected areas of the San Francisco Bay Area in relation to reserve size, topographic complexity and distance from the ocean. Results: Under the two climate change scenarios, current climates across most of California and Nevada will shrink greatly in extent, and the climates of the highest peaks will disappear from this region. Expanding and novel climates are projected for the Central Valley. Current temperature isoclines are projected to move up to 4.9 km year-1 in flatter regions, but substantially slower in mountainous areas because of steep local topoclimate gradients. In the San Francisco Bay Area, climate diversity within currently protected areas increases with reserve size and proximity to the ocean (the latter because of strong coastal climate gradients). However, by 2100 of almost 500 protected areas (>100 ha), only eight of the largest are projected to experience temperatures within their currently observed range. Topoclimate variability will further increase the range of conditions experienced and needs to be incorporated in future analyses. Main Conclusions: Spatial heterogeneity in climate, from mesoclimate to topoclimate scales, represents an important spatial buffer in response to climate change, and merits increased attention in conservation planning. © 2010 Blackwell Publishing Ltd.


Ackerly D.D.,University of California at Berkeley | Cornwell W.K.,University of New South Wales | Weiss S.B.,Creekside Center for Earth Observation | Flint L.E.,U.S. Geological Survey | Flint A.L.,U.S. Geological Survey
PLoS ONE | Year: 2015

Changes in climate projected for the 21st century are expected to trigger widespread and pervasive biotic impacts. Forecasting these changes and their implications for ecosystem services is a major research goal. Much of the research on biotic responses to climate change has focused on either projected shifts in individual species distributions or broadscale changes in biome distributions. Here, we introduce a novel application of multinomial logistic regression as a powerful approach to model vegetation distributions and potential responses to 21st century climate change. We modeled the distribution of 22 major vegetation types, most defined by a single dominant woody species, across the San Francisco Bay Area. Predictor variables included climate and topographic variables. The novel aspect of our model is the output: a vector of relative probabilities for each vegetation type in each location within the study domain. The model was then projected for 54 future climate scenarios, spanning a representative range of temperature and precipitation projections from the CMIP3 and CMIP5 ensembles. We found that sensitivity of vegetation to climate change is highly heterogeneous across the region. Surprisingly, sensitivity to climate change is higher closer to the coast, on lower insolation, north-facing slopes and in areas of higher precipitation. While such sites may provide refugia for mesic and cool-adapted vegetation in the face of a warming climate, the model suggests they will still be highly dynamic and relatively sensitive to climate-driven vegetation transitions. The greater sensitivity of moist and low insolation sites is an unexpected outcome that challenges views on the location and stability of climate refugia. Projections provide a foundation for conservation planning and land management, and highlight the need for a greater understanding of the mechanisms and time scales of potential climate-driven vegetation transitions. © 2015, Public Library of Science. All rights reserved. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

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