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Antonarakis AS, Bogan SA, Goulden ML, Moorcroft PR. Impacts of the 2012-2015 Californian drought on carbon, water and energy fluxes in the Californian Sierras: Results from an imaging spectrometry-constrained terrestrial biosphere model. GLOBAL CHANGE BIOLOGY 2022; 28:1823-1852. [PMID: 34779555 DOI: 10.1111/gcb.15995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/15/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Accurate descriptions of current ecosystem composition are essential for improving terrestrial biosphere model predictions of how ecosystems are responding to climate variability and change. This study investigates how imaging spectrometry-derived ecosystem composition can constrain and improve terrestrial biosphere model predictions of regional-scale carbon, water and energy fluxes. Incorporating imaging spectrometry-derived composition of five plant functional types (Grasses/Shrubs, Oaks/Western Hardwoods, Western Pines, Fir/Cedar and High-elevation Pines) into the Ecosystem Demography (ED2) terrestrial biosphere model improves predictions of net ecosystem productivity (NEP) and gross primary productivity (GPP) across four flux towers of the Southern Sierra Critical Zone Observatory (SSCZO) spanning a 2250 m elevational gradient in the western Sierra Nevada. NEP and GPP root-mean-square-errors were reduced by 23%-82% and 19%-89%, respectively, and water flux predictions improved at the mid-elevation pine (Soaproot), fir/cedar (P301) and high-elevation pine (Shorthair) flux tower sites, but not at the oak savanna (San Joaquin Experimental Range [SJER]) site. These improvements in carbon and water predictions are similar to those achieved with model initializations using ground-based inventory composition. The imaging spectrometry-constrained ED2 model was then used to predict carbon, water and energy fluxes and above-ground biomass (AGB) dynamics over a 737 km2 region to gain insight into the regional ecosystem impacts of the 2012-2015 Californian drought. The analysis indicates that the drought reduced regional NEP, GPP and transpiration by 83%, 40% and 33%, respectively, with the largest reductions occurring in the functionally diverse, high basal area mid-elevation forests. This was accompanied by a 54% decline in AGB growth in 2012, followed by a marked increase (823%) in AGB mortality in 2014, reflecting an approximately 10-fold increase in per capita tree mortality from ~55 trees km-2 year-1 in 2010-2011, to ~535 trees km-2 year-1 in 2014. These findings illustrate how imaging spectrometry estimates of ecosystem composition can constrain and improve terrestrial biosphere model predictions of regional carbon, water, and energy fluxes, and biomass dynamics.
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Affiliation(s)
| | - Stacy A Bogan
- Department of Geography, Sussex University, Brighton, UK
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Michael L Goulden
- Department of Earth Sciences, University of California, Irvine, California, USA
| | - Paul R Moorcroft
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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Roberts LJ, Burnett R, Tietz J, Veloz S. Recent drought and tree mortality effects on the avian community in southern Sierra Nevada: a glimpse of the future? ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01848. [PMID: 30786092 DOI: 10.1002/eap.1848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 10/31/2018] [Accepted: 12/04/2018] [Indexed: 06/09/2023]
Abstract
Birds respond rapidly to changes in both habitat and climate conditions and thus are good indicators of the ecological effects of a changing climate, which may include warmer temperatures, changing habitat conditions, and increased frequency and magnitude of extreme events like drought. We investigated how a widespread tree mortality event concurrent with a severe drought influenced the avian community of the Sierra Nevada mountain range in California. We assessed and compared the separate effects of climate stresses and altered habitat conditions on the avian community and used this information to evaluate the changes that are likely to occur in the near future. We built tree mortality maps from freely available Landsat imagery with Google Earth Engine. We analyzed avian point counts from 2010 to 2016 in the southern Sierra Nevada, to model temperature, water deficit, and tree mortality effects on the abundances of 45 bird species, and then used these models to project abundances into the future based on three climate projections. A large portion of the avian community, 47%, had a positive relationship with temperature increase, compared to 20% that responded negatively. More species (36%) declined with drier conditions than increased (29%). More species declined in response to high tree mortality (36%) than increased (9%). A preponderance of species adapted to colder temperatures (higher elevation) had negative responses to high tree mortality and water deficit, but positive responses to increasing temperature. We projected the highest total bird abundances in the future under the warmest climate scenario that we considered, but habitat modification (e.g., tree mortality) and water deficit could offset the positive influence of temperature for many species. As other studies have shown, climate warming may lead to substantial but idiosyncratic effects on wildlife species that could result in community composition shifts. We conclude that future climate conditions may not have a universally negative effect on biodiversity in the Sierra Nevada, but probable vegetation changes and increased likelihood of extreme events such as drought should be incorporated into climate-smart forest and wildlife management decisions.
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Affiliation(s)
- L Jay Roberts
- Point Blue Conservation Science, 3820 Cypress Drive, #11, Petaluma, California, 94954, USA
| | - Ryan Burnett
- Point Blue Conservation Science, 3820 Cypress Drive, #11, Petaluma, California, 94954, USA
| | - James Tietz
- Point Blue Conservation Science, 3820 Cypress Drive, #11, Petaluma, California, 94954, USA
| | - Sam Veloz
- Point Blue Conservation Science, 3820 Cypress Drive, #11, Petaluma, California, 94954, USA
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Fernandez i Marti A, Dodd RS. Using CRISPR as a Gene Editing Tool for Validating Adaptive Gene Function in Tree Landscape Genomics. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00076] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Rogers BM, Solvik K, Hogg EH, Ju J, Masek JG, Michaelian M, Berner LT, Goetz SJ. Detecting early warning signals of tree mortality in boreal North America using multiscale satellite data. GLOBAL CHANGE BIOLOGY 2018; 24:2284-2304. [PMID: 29481709 DOI: 10.1111/gcb.14107] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 02/12/2018] [Indexed: 05/19/2023]
Abstract
Increasing tree mortality from global change drivers such as drought and biotic infestations is a widespread phenomenon, including in the boreal zone where climate changes and feedbacks to the Earth system are relatively large. Despite the importance for science and management communities, our ability to forecast tree mortality at landscape to continental scales is limited. However, two independent information streams have the potential to inform and improve mortality forecasts: repeat forest inventories and satellite remote sensing. Time series of tree-level growth patterns indicate that productivity declines and related temporal dynamics often precede mortality years to decades before death. Plot-level productivity, in turn, has been related to satellite-based indices such as the Normalized difference vegetation index (NDVI). Here we link these two data sources to show that early warning signals of mortality are evident in several NDVI-based metrics up to 24 years before death. We focus on two repeat forest inventories and three NDVI products across western boreal North America where productivity and mortality dynamics are influenced by periodic drought. These data sources capture a range of forest conditions and spatial resolution to highlight the sensitivity and limitations of our approach. Overall, results indicate potential to use satellite NDVI for early warning signals of mortality. Relationships are broadly consistent across inventories, species, and spatial resolutions, although the utility of coarse-scale imagery in the heterogeneous aspen parkland was limited. Longer-term NDVI data and annually remeasured sites with high mortality levels generate the strongest signals, although we still found robust relationships at sites remeasured at a typical 5 year frequency. The approach and relationships developed here can be used as a basis for improving forest mortality models and monitoring systems.
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Affiliation(s)
| | | | - Edward H Hogg
- Northern Forestry Centre, Canadian Forest Service, Natural Resources Canada, Edmonton, AB, Canada
| | - Junchang Ju
- Biospheric Science Laboratory (Code 618), NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Jeffrey G Masek
- Biospheric Science Laboratory (Code 618), NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Michael Michaelian
- Northern Forestry Centre, Canadian Forest Service, Natural Resources Canada, Edmonton, AB, Canada
| | - Logan T Berner
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Scott J Goetz
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
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Thorne JH, Choe H, Boynton RM, Bjorkman J, Albright W, Nydick K, Flint AL, Flint LE, Schwartz MW. The impact of climate change uncertainty on California's vegetation and adaptation management. Ecosphere 2017. [DOI: 10.1002/ecs2.2021] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- James H. Thorne
- Department of Environmental Science and Policy University of California Davis California 95616 USA
| | - Hyeyeong Choe
- Department of Environmental Science and Policy University of California Davis California 95616 USA
| | - Ryan M. Boynton
- Department of Environmental Science and Policy University of California Davis California 95616 USA
| | - Jacquelyn Bjorkman
- Department of Environmental Science and Policy University of California Davis California 95616 USA
| | - Whitney Albright
- California Department of Fish and Wildlife 1416 Ninth Street, Suite 1221 Sacramento California 95814 USA
| | - Koren Nydick
- Sequoia and Kings Canyon National Parks Three Rivers California 93271 USA
| | - Alan L. Flint
- US Geological Survey Placer Hall, 6000 J Street Sacramento California 95819‐6129 USA
| | - Lorraine E. Flint
- US Geological Survey Placer Hall, 6000 J Street Sacramento California 95819‐6129 USA
| | - Mark W. Schwartz
- Department of Environmental Science and Policy University of California Davis California 95616 USA
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Detecting Drought-Induced Tree Mortality in Sierra Nevada Forests with Time Series of Satellite Data. REMOTE SENSING 2017. [DOI: 10.3390/rs9090929] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A five-year drought in California led to a significant increase in tree mortality in the Sierra Nevada forests from 2012 to 2016. Landscape level monitoring of forest health and tree dieback is critical for vegetation and disaster management strategies. We examined the capability of multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) in detecting and explaining the impacts of the recent severe drought in Sierra Nevada forests. Remote sensing metrics were developed to represent baseline forest health conditions and drought stress using time series of MODIS vegetation indices (VIs) and a water index. We used Random Forest algorithms, trained with forest aerial detection surveys data, to detect tree mortality based on the remote sensing metrics and topographical variables. Map estimates of tree mortality demonstrated that our two-stage Random Forest models were capable of detecting the spatial patterns and severity of tree mortality, with an overall producer’s accuracy of 96.3% for the classification Random Forest (CRF) and a RMSE of 7.19 dead trees per acre for the regression Random Forest (RRF). The overall omission errors of the CRF ranged from 19% for the severe mortality class to 27% for the low mortality class. Interpretations of the models revealed that forests with higher productivity preceding the onset of drought were more vulnerable to drought stress and, consequently, more likely to experience tree mortality. This method highlights the importance of incorporating baseline forest health data and measurements of drought stress in understanding forest response to severe drought.
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Recent Patterns in Climate, Vegetation, and Forest Water Use in California Montane Watersheds. FORESTS 2017. [DOI: 10.3390/f8080278] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Young DJN, Stevens JT, Earles JM, Moore J, Ellis A, Jirka AL, Latimer AM. Long‐term climate and competition explain forest mortality patterns under extreme drought. Ecol Lett 2016; 20:78-86. [DOI: 10.1111/ele.12711] [Citation(s) in RCA: 255] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/22/2016] [Accepted: 11/04/2016] [Indexed: 12/16/2022]
Affiliation(s)
- Derek J. N. Young
- Graduate Group in Ecology and Department of Plant Sciences University of California‐Davis Davis, CA, USA
| | - Jens T. Stevens
- John Muir Institute of the Environment University of California‐Davis Davis, CA, USA
| | - J. Mason Earles
- School of Forestry and Environmental Studies Yale University New Haven, CT, USA
| | - Jeffrey Moore
- USDA Forest Service Pacific Southwest Region Davis, CA, USA
| | - Adam Ellis
- USDA Forest Service Pacific Southwest Region Davis, CA, USA
| | - Amy L. Jirka
- USDA Forest Service Pacific Southwest Region Davis, CA, USA
| | - Andrew M. Latimer
- Department of Plant Sciences University of California‐Davis Davis, CA, USA
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