Progress 07/01/06 to 06/30/10
Outputs
OUTPUTS: The project was focused around a field experiment designed to test for interactions of environmental gradients of resource availability with plant strategies of resource allocation to growth and regeneration mode. The experiment was conducted by the PI supervising four undergraduate research assistants, one of whom undertook a concurrent EPSCoR summer internships. The experiment was implemented in two parts that were geographically separated (in different parts of western Nevada) but conceptually continuous along an elevation/precipitation/temperature gradient: (1) from the crest of the Carson Range at c. 8000 ft elevation to flats of the Carson River valley at c. 5000 ft elevation (4 elevational sites), and (2) from a high point in the Desatoya Range at c. 6000 ft elevation to a low point in the Gabbs Valley at c. 4000 ft elevation (6 elevational sites). For all woody species abundant at each site, five randomly selected individuals of average plant size were excavated, their entire structure separated into component tissue types, the tissues dried and weighed, subsamples taken, and ground and prepared for analysis of carbon and nitrogen content and mineral, sugar and starch content In addition, at each site, twenty plants of each woody species were randomly selected and assigned to one of four clipping treatments (0, 10, 30 and 90 % removal of canopy) for assessment of resprouting response over the next 12 months.. Although there was significant variation between species and individuals within-species, non-sprouters tended to low allocations to roots and starch, but higher allocations to stems (rather than leaves) and simple sugars and higher tissue nitrogen concentrations. Non-sprouters showed little response along the elevation/ productivity gradient. Sprouters, tended to high allocations to roots and starch, and low allocation to stems and simple sugars, and low nitrogen concentrations. Sprouters responded to productivity differences, allocating proportionately less to roots and starch at higher precipitation. This result suggests, at least in the short term, a greater resilience of sprouters to decreasing precipitation as predicted for the Great Basin by some climate change models. Progressive results and implications have been communicated in a series of conference papers during the project and continue to be disseminated in journal papers in submission and preparation. The work has also been presented at three seminars for BLM and USFS staff in Nevada, California and Oregon and three University of Nevada Reno Ag Experiment Station open days. Broader outreach includes presentation of results and conclusions in the contents of two UNR undergraduate courses (NRES493/693 Forest and Range Ecology and NRES495/695 Fire Ecology and Management), one informal graduate seminar program (UNR Plant Talk), two Washoe County school science fairs, and two Washoe County school field trips on fire ecology. Mid-project, a new collaboration has been established with Dr Lars Walker (UNLV) to apply the theory behind this project more widely to ecosystems throughout the USA. PARTICIPANTS: 1. Ashley Sparrow (PI). Overall project management. Established liaison with land managers in local government and federal agencies for permission to undertake experiments and collection samples. Submitted materials required to obtain research permits, including NEPA clearances. Designed experimental set-up and selected analytical protocols. Selected field plots. Mapped and harvested plants. Supervised sample preparation for chemical analyses. Managed data collation and checking prior to analysis. 2. Jonathon Ebert, Doug Holderman, Galen Smith, Annie Staehlin (undergraduate research assistants). Under PI supervision, obtained equipment to conduct field experiment. Mapped plants on experimental plots. Applied clipping treatments to randomly selected plants. Harvested plants to determine total biomass and obtain specimens of leaves, coarse and fine stems, fruits and coarse roots. Dried and weighed tissue specimens. Ground subsamples of tissues ready for chemical analysis. Prepared tissue samples for analysis of carbon, nitrogen, total minerals (ashed), sugar and starch content. 3. John Cushman, Biochemistry Dept, University of Nevada Reno (new collaborator). Advised on selection of sugar and starch analysis methods. Provided training to undergraduate research assistants. 4. Bob Blank and Tye Morgan, USDA ARS, Reno (new collaborators). Analyzed tissue specimens for carbon, nitrogen and mineral (ashed) content. TARGET AUDIENCES: 1. Current federal agency staff. The Bureau of Land Management and the Forest Service are the principle agencies that benefit from a broader understanding of how plant species' growth, resource allocation, life history and regeneration characteristics under different environmental conditions can be used to predict future ecosystem change associated with climate change, changes in the wildfire regime and further introductions or spreading of exotic species. For the project duration, agency interactions focused around the Carson City field office of BLM, through their involvement in establishment of experiments and demonstration of experimental results and their interpretation. USFS staff have been made aware of the results through local meetings of staff professional organizations, specifically local branches of the Society of American Foresters. 2. Future agency staff i.e. undergraduate and graduate students undertaking degrees in resource management. There has been direct involvement of four undergraduate research assistants in the project, but wider exposure to project concepts and results was achieved by using project materials in University of Nevada Reno classes, especially NRES493/693 Forest and Range Ecology and NRES495/695 Fire Ecology and Management. 3. Private landholders, federal-lands permittees, and the general public. communication about project goals and results occur throughout the project via a variety of pathways, which have included annual Nevada Agriculture Experiment Station open days, the state convention of the Future Farmers of America in 2008, and numerous school science fairs in Washoe County, Nevada. PROJECT MODIFICATIONS: The nature of the experiment was modified in 2008. Rather than a two-site experiment based on a phylogenetically independent contrast of two species of Artemisia (sagebrush) subject to different manipulated water regimes, the experiment used a natural precipitation gradient and compared plant responses across eight species at ten sites. The change was experimentally more tractable in the field and gave a more generalizable result for woody plant species common throughout the Great Basin.
Impacts
Change of knowledge: The experiments provided evidence of the strong dependence of the relatively uncommon phenomenon of post-fire resprouting on landscape position within the broad Great Basin region. Resprouting is more abundant in higher elevation, higher precipitation zones (with a significant fire regime) and lower precipitation (with a rare-fire regime) than in intermediate precipitation zones. This hypothesis about the interaction of site productivity and ecophysiological controls on resprouting has significant implications for the potential patterns of invasion of Great Basin sagebrush ecosystems by exotic post-fire resprouting species in the long term. Change of action: Preliminary discussions have been held with BLM managers about the using these results to improve assessment of long-term potential invasion threats beyond current foci on annual species such as cheatgrass and whitetop. Recent data obtained at the conclusion of the experiment continue to provide greater leverage for convincing managers to plan and monitor on a longer time horizon for climate change and invasive species within the landscape heterogeneity and inter-annual variability of the Great Basin.
Publications
- Sparrow, A.D. 2006. Fire in arid and semi-arid landscapes: special characteristics, ecological impacts and evolutionary outcomes. 3rd International Fire Ecology and Management Congress. San Diego, USA, 13-17 November 2006.
- Ko, D., Weisberg, P. & Sparrow, A. 2007. Landscape simulation modeling of anthropogenic impacts on pinyon-juniper woodland distribution during early settlement: Nevada Great Basin. 22nd US Conference of the International Association for Landscape Ecology, Tucson, USA, 9-13 April, 2007.
- Bellingham, P.J & Sparrow, A.D. 2009. Multi-stemmed trees in rain forests: relationships with environment and implications for forest dynamics. Journal of Ecology, 97: 472-483.
- Rodriguez Barahona, L., Sparrow, A. and Rollins, K. 2009. A resilience-based model for the sagebrush steppe subject to invasive annual grasses and wildfires. Environmental and Resource Economics Early Career Researcher Workshop (E-CReW 2009), Bathurst, Australia, 3-4 November 2009.
- Rodriguez, L., Sparrow, A., and Rollins, K. 2009. A resilience-based model for the sagebrush steppe subject to invasive annual grasses and wildfires. SageStep Annual Meeting, Winnemucca, NV, 9-11 June 2009.
- Sparrow, A.D., Bellingham, P.J. Dungan, R.J., Young, L.M. & Kelly, D. 2010 Resprouters and seeders: their utility as functional groups in a novel fire regime. Annals of Botany, submitted.
- Sparrow, A.D. 2010 Interpreting wildfire regimes in the Great Basin sagebrush ecosystems: Logical consistency to underpin management. In advanced preparation for Rangeland Ecology and Management.
- Sparrow, A.D. 2010 Fire regimes in deserts: the universal and the unique. In advanced preparation for Journal of Arid Environments
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: In the absence of a graduate research assistant to help implement and manage previously planned field components of the project, the focus was redirected around an alternative field experiment designed to test for interactions of environmental gradients of resource availability with plant strategies of resource allocation to growth and regeneration mode. The experiment has been conducted by the PI supervising three undergraduate research assistants, two of whom undertook summer internships. The experiment has been designed in two parts that are geographically separated (in different parts of western Nevada) but conceptually continuous along an elevation/precipitation/temperature gradient. Part 1 examines this gradient from the crest of the Carson Range at c. 8000 ft elevation to flats of the Carson River valley at c. 5000 ft elevation. Part 2 examines the gradient from a high point in the Desatoya Range at c. 6000 ft elevation to a low point in the Gabbs Valley at c. 4000 ft elevation. Installation of Part 2 was delayed over the summer of 2008 due to the BLM's timeframe for processing the NEPA application and conducting a cultural resources' assessment required to permit soil disturbance and collection of plant root samples. Because of seasonal constraints, this part must now be installed in Spring 2009. Part 1 was fully implemented in the Carson Range. Four sites were selected and established at elevational intervals of c. 1000 ft. Lower elevation sites are dominated by sagebrush, rabbitbrush and antelope bitterbrush, whilst higher elevation sites contain a mix of sagebrush, bitterbrush, manzanita and tobacco bush. For all woody species abundant at each site, five randomly selected individuals of average plant size were excavated, their entire structure separated into component tissue types, the tissues dried and weighed, subsamples taken, and ground and prepared for analysis of carbon and nitrogen content (complete) and mineral, sugar and starch content (still to be completed, by Spring 2009). New collaborations have been established with Drs John Cushman (UNR) and Bob Blank (ARS) to facilitate these last analyses. In each plot, twenty plants of each woody species were randomly selected and assigned to one of four clipping treatments (0, 10, 30 and 90 % removal of above-ground biomass) for assessment of resprouting response (occurrence and rate) over the next 12 months. A teaching-research nexus has been developed around the experiment. The experimental design was partly inspired by graduate-student discussions and project work in the NRES495/695 Fire Ecology and Management class during 2007 and students in the same course in Spring 2009 will have the opportunity for field visits to see the effects of the clipping treatments and relate these to the growth and resource allocation data that will be available at that time. In addition a new collaboration has been established with Dr Lars Walker (UNLV) to apply the theoretical underpinnings of this project more widely to ecosystem subject to significant disturbance regimes throughout the USA. PARTICIPANTS: 1. Ashley Sparrow (PI). Overall project management. Established liaison with land managers in local government and federal agencies for permission to undertake experiments and collection samples. Submitted materials required to obtain research permits, including NEPA clearances. Designed experimental set-up and selected analytical protocols. Selected field plots. Mapped and harvested plants. Supervised sample preparation for chemical analyses. Managed data collation and checking prior to analysis. 2. Doug Holderman, Galen Smith, Annie Staehlin (undergraduate research assistants). Under PI supervision, obtained equipment to conduct field experiment. Mapped plants on experimental plots. Applied clipping treatments to randomly selected plants. Harvested plants to determine total biomass and obtain specimens of leaves, coarse and fine stems, fruits and coarse roots. Dried and weighed tissue specimens. Ground subsamples of tissues ready for chemical analysis. Prepared tissue samples for analysis of carbon, nitrogen, total minerals (ashed), sugar and starch content. 3. John Cushman, Biochemistry Dept, University of Nevada Reno (new collaborator). Advised on selection of sugar and starch analysis methods. Provided training to undergraduate research assistants. 4. Bob Blank and Tye Morgan, USDA ARS, Reno (new collaborators). Analyzed tissue specimens for carbon, nitrogen and mineral (ashed) content. TARGET AUDIENCES: 1. Current federal agency staff. The Bureau of Land Management and the Forest Service are the principle agencies that will benefit from a broader understanding of how plant species' growth, resource allocation, life history and regeneration characteristics under different environmental conditions can be used to predict future ecosystem change associated with climate change, changes in the wildfire regime and further introductions or spreading of exotic species. In the last twelve months, agency interactions have been focused around the Carson City field office of BLM, through their involvement in establishment of experiments. It is planned to expand and strengthen communications with agencies during 2009 as experimental results, analysis and interpretation with respect to management progress, including via professional organizations such as the Society of Range Management and the Society of American Foresters, especially their local branches. 2. Future agency staff i.e. undergraduate and graduate students undertaking degrees in resource management. There has been direct involvement of three undergraduate research assistants in the project, but wider exposure to project concepts and results is achieved by using project materials in University of Nevada Reno classes, especially NRES493/693 Forest and Range Ecology (Spring 2008) and NRES495/695 Fire Ecology and Management (coming in Spring 2009). 3. Private landholders, federal-lands permittees, and the general public. Communication about project goals and results occur throughout the project via a variety of pathways, which in 2008 have included a Nevada Agriculture Experiment Station open day, the state convention of the Future Farmers of America, and a school science fair. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Change of knowledge: Implementation of the new experimental sites has provided further evidence of the strong dependence of the relatively uncommon phenomenon of post-fire resprouting on landscape position within the broad Great Basin region. Resprouting is more abundant in higher elevation, higher precipitation zones (with a significant fire regime) and lower precipitation (with a rare-fire regime) than in intermediate precipitation zones. This hypothesis about the interaction of site productivity and ecophysiological controls on resprouting will have significant implications for the potential patterns of invasion of Great Basin sagebrush ecosystems by exotic post-fire resprouting species in the long term. Change of action: Preliminary discussions have been held with BLM managers about the using these results to improve assessment of long-term potential invasion threats beyond current foci on annual species such as cheatgrass and whitetop. Complete data at the end of the experiment will provide the ability to justify conclusions rigorously and provide greater leverage for convincing managers to plan and monitor on a longer time horizon.
Publications
- Ko, D., Weisberg, P., Sparrow, A. & Condon, L. 2008. Fire regime, legacy effects, and cheatgrass invasion in the Great Basin of central Nevada. 23rd US International Association of Landscape Ecology Symposium. Madison, USA, 6-10 April 2008.
- Standish, R.J., Williams, P.A., Hobbs, R.J. and Sparrow, A.D. 2008. A state-and-threshold model for the restoration of abandoned farmland. In. R.J. Hobbs & K.N. Suding (eds). New Models for Ecosystem Dynamics and Restoration. Island Press, Washington DC. pp.189-205.
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Progress 01/01/07 to 12/31/07
Outputs
An experiment has been established in the Sierra Valley, near Loyalton, CA. The site offers a unique opportunity to test the project's hypotheses about the dearth of resprouting in the Great Basin flora, since two species of sagebrush with different abilities to resprout (mountain big sage, Artemisia tridentata, a non-sprouter; silver sage, A. cana, a strong resprouter) grow almost side by side in adjoining habitats. Plants of both species have been selected for manipulation of precipitation received and measurement of growth responses above and below ground. To examine the effects of reduced precipitation, a precipitation throughfall interception device, previous developed by others for forest ecosystems, has been modified and extensively tested for use with sagebrush. The device consists of gently sloping parallel rows of half-pipe that intercept 50% of falling snow and rain, and then transport the precipitation (when liquid) downslope away from the rooting zone of
focal plants. This runoff is then "recycled" to water other plants, thereby providing a second treatment that simulates increased precipitation, with the distinct benefit that the precipitation is delivered at the same time as the natural precipitation falls and/or melts - i.e. precipitation is pulsed with natural timing, but greater magnitude, a significant advance in terms of other low-technology means of supplemental experimental watering. A PhD-level graduate research assistant, Sarah Luxton, was appointed to the project in January 2007, but for personal reasons chose to terminate studies in August 2007. In her absence, two UNR undergraduate research assistants, Doug Holderman and Kari-Anne Staehlin, have had the opportunity to develop hands-on experience of ecological research by close participation in the experimental set-up. These undergrads have received a high level of mentoring by PI Sparrow, and one (Holderman) applied for and received an NSF/EPSCOR Summer Scholarship. In
January 2008, a new MS-level graduate research assistant, Mark Rincon, will join the project team. The project aims and methods have been incorporated into teaching of the UNR natural resources curriculum at both undergraduate (NRES100 Natural Resources and NRES 493 Fire Ecology t) and graduate level, including class visits to the experimental area. The project has also been the subject of outreach and publicity, including an extended interview of PI Sparrow about wildfire in the Great Basin on local radio (station KTHX) and a series of wildfire-focused fieldtrips for elementary school students (Mountain View Montessori) guided by PI Sparrow (with local newspaper coverage). Range management program staff from Federal agencies in Nevada, California and Oregon have been kept abreast of project progress. Consultative meetings have been held with four BLM offices and with Death Valley National Park. Agency staff reacted by seeking advice on expanding their management models for local
sagebrush rangeland to include larger landscape scales and longer-term evolutionary perspectives. In response, four new research/contract proposals were submitted and are pending for funding to start in 2008.
Impacts
Change in Knowledge: There have been two principle advancements in knowledge during 2007. Firstly, the search for suitable experimental sites revealed the strong dependence of the relatively uncommon phenomenon of post-fire resprouting on landscape position within the broader Great Basin sagebrush ecosystem. This finding has provided a series of new hypotheses about site productivity and ecophysiological controls on resprouting, which have been incorporated into the experimental design at the Sierra Valley site. These hypotheses, if supported, will have significant implications for the potential patterns of invasion of Great Basin sagebrush ecosystems by exotic post-fire resprouting species in the long term. Secondly, the project has developed an inexpensive, passive, low-technology and robust means for experimental manipulation of precipitation regimes in shrubby desert ecosystems. Given the importance of plant-available water to the long-term sustainability of arid
Western ecosystems, this tractable method will have significant benefits for future research on our ability to understand and predict the impacts of changed precipitation regimes. Change in Actions: Two discussion documents about wildfire regimes and long-term ecological change (past and future) circulated amongst range management staff at BLM and Death Valley National Park, and follow-up small-group meetings offered by PI Sparrow, have prompted agency staff to rethink their expectations of ecosystem function in terms of "natural" processes and potential future change, including the threats from invasive exotic species and encroaching native species. Whilst there have yet to be changes in policy or regulation or their respective implementation on the ground, agency staff have responded by requesting proposals for further research that relates to their specific management areas (see Outputs section). In the case of Death Valley National Park, PI Sparrow has been asked to join a science
strategy advisory group to be chaired by Park Assistant Chief of Resources Management, David Ek.
Publications
- Ko, D., Weisberg, P. & Sparrow, A. 2007. Landscape simulation modeling of anthropogenic impacts on pinyon-juniper woodland distribution during early settlement: Nevada Great Basin (abstract). 22nd US Conference of the International Association for Landscape Ecology, Tucson, USA, 9-13 April, 2007.
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Progress 07/01/06 to 12/31/06
Outputs
Whilst Great Basin vegetation types display clear post-fire succession pathways, the flora apparently shows only scant evidence of one life history adaptation - resprouting - that is very common in all other fire-prone ecosystems around the world. This research project addresses two questions arising from the apparent dearth of resprouting: (1) Why is resprouting so uncommon in the Great Basin? and (2) Is the Great Basin under threat of invasion by exotic resprouting species adapted to the modern fire regime? The two overarching goals of the project are to answer these two questions. Progress to date (in the period July 1 - December 31, 2006) can be summarized with respect to the project's specific Milestones: Milestone 1 (July-August 2006): Employment of research assistant. A graduate research assistant, Sarah Luxton (BSc.[Hons.] Univ. Canterbury), was hired and enrolled in the EECB interdisciplinary PhD programme at UNR. However, her start date was delayed until
January 22, 2007, because of personal circumstances and delays with paperwork for her international student visa. A six-month extension of the timeframe for funding of her RAship was sought and approved. Milestone 2 (September-December 2006): Collation of existing data on resprouting by both native and exotic woody species. Two UNR/NRES undergraduate research interns, Trevor Fitcha and Doug Holderman, were employed part-time during the spring semester to undertake the literature review of native and exotic species' life history strategies with respect to disturbance regimes and ecophysiological constraints in the Great Basin. The search results have been summarized as annotated Endnote citation databases, with accompanying collections of papers as PDFs and hardcopy. These databases formed the basis of a conference paper on fire in arid/desert environments, presented at the 3rd International Fire Ecology and Management Congress in San Diego (November 13-17, 2007); see publications
section below). The presentation is being reworked as a review paper for submission to the Journal of Arid Environments (or similar) during 2007. Preparation for Milestones in 2007: Meta-analysis of existing data sets (January-April 2007). The undergraduate interns have begun compilation of a summary spreadsheet of findings from the literature search, in preparation for the meta-analysis of drivers of resprouting in the Great Basin flora. Establishment of experimental sites for both native and exotic species (May-August 2007) A 4x4 pickup truck has been purchased and examination of potential experimental sites near Reno, Austin and Denio has begun.
Impacts
This research will provide new information for federal and state land-management agencies and for individual private land managers with regard to two significant current and near-future land-management issues in the Great Basin: (1) management of native plant communities in ecologically and economically sustainable ways, in the face of fire and other disturbances; (2) monitoring for, and management of, exotic woody weeds. Transfer of project findings, implication and management recommendations has already been foreshadowed through a series of workshops scheduled towards the end of the three-year funding period (final project Milestone). The project has already made an impact. The research question and approach has piqued the interest of several federal agency field offices: BLM Cedarville, BLM Lakeview, FWS Sheldon and Hart Mountain Refuges. BLM Carson City interest could not be sustained upon the retirement of fire ecologist Mike McQueen. These agency offices have
supported and collaborated the preparation of a pending $958,000 application to the Joint Fire Sciences Program to fund a project titled "Resilience of Wyoming big sagebrush ecosystems: Assessing fire management options for long-term habitat sustainability". The project would include experimental manipulations and measurements across three states (northwestern Nevada, northeastern California and southeastern Oregon), plus extensive education and outreach activities with government and private land managers.
Publications
- Sparrow, A.D. 2006. Fire in arid and semi-arid landscapes: special characteristics, ecological impacts and evolutionary outcomes. 3rd International Fire Ecology and Management Congress. San Diego, USA, 13-17 November 2006.
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