@inbook {JRN54669, title = {Grassland Communities and Ecosystems}, booktitle = {Reference Module in Life Sciences}, year = {2017}, publisher = {Elsevier}, organization = {Elsevier}, abstract = {

This chapter describes global grassland communities and grassland ecosystems.

Grasslands represent one of the largest vegetation types on Earth and their existence is determined by water scarcity that in turn depends on precipitation and temperature. This vegetation type harbors a high diversity of plant species that mostly occurs at fine spatial scales because grasslands tend to be structurally simpler at coarser scales. Grassland species richness has strong and positive effects on primary production as a result of increasing niche complementarity with increasing diversity. Grasslands are among the most vulnerable ecosystems in the world because their diversity is threatened by human activity, mostly as a consequence of conversion into croplands.

}, keywords = {grassland communities, grassland ecosystems}, issn = {978-0-12-809633-8}, doi = {10.1016/B978-0-12-809633-8.02201-9}, author = {O. E. Sala and L. Vivanco and P. Flombaum} } @inbook {JRN54687, title = {Rangeland ecosystem services: nature{\textquoteright}s supply and humans{\textquoteright} demand}, booktitle = {Rangeland Systems: Processes, Management and Challenges}, year = {2017}, pages = {467-489}, publisher = {Springer}, organization = {Springer}, chapter = {14}, address = {New York}, abstract = {

Ecosystem services are the benefits that society receives from nature and they include the regulation of climate, the pollination of crops, the provisioning of intellectual inspiration and recreational environment, as well as many essential goods such as food, fiber, and wood. Rangeland ecosystem services are often valued differently by different stakeholders interested in livestock production, water quality and quantity, biodiversity conservation, or carbon sequestration. The supply of ecosystem services depends on biophysical conditions and land use history and it is assessed using surveys of soils, plants and animals. The demand for ecosystem services depends on educational level, income and location of residence; and it is assessed with stakeholder interviews and questionnaires/surveys. Rangeland management affects the supply of different ecosystem services by producing tradeoffs among services. Tradeoffs result when an increase in one service is associated with a decline in another and win-win situations occur when an increase in one service is associated with an increase in other services. This chapter provides a conceptual framework in which range management decisions are seen as a challenge of reconciling supply and demand of ecosystem services.

}, keywords = {cultural, ecosystem services, human well-being, provisioning, regulation, stakeholders, trade-offs, win{\textendash}win}, issn = {978-3-319-46709-2}, doi = {10.1007/978-3-319-46709-2_14}, url = {files/bibliography/17-008.pdf}, author = {O. E. Sala and Laura Yahdjian and Kris Havstad and M. Aguiar} } @article {JRN54167, title = {Enhanced precipitation variability effects on water losses and ecosystem functioning: differential response of arid and mesic regions}, journal = {Climate Change}, volume = {131}, year = {2015}, month = {07/2015}, pages = {213-227}, chapter = {213}, abstract = {

Climate change will result in increased precipitation variability with more extreme events reflected in more frequent droughts as well as more frequent extremely wet conditions. The increase in precipitation variability will occur at different temporal scales from intra to inter-annual and even longer scales. At the intra-annual scale, extreme precipitation events will be interspersed with prolonged periods in between events. At the inter-annual scale, dry years or multi-year droughts will be combined with wet years or multi-year wet conditions. Consequences of this aspect of climate change for the functioning ecosystems and their ability to provide ecosystem services have been underexplored. We used a process-based ecosystem model to simulate water losses and soil-water availability at 35 grassland locations in the central US under 4 levels of precipitation variability (control, +25, +50+75 \%) and six temporal scales ranging from intra- to multi-annual variability. We show that the scale of temporal variability had a larger effect on soil-water availability than the magnitude of variability, and that inter- and multi-annual variability had much larger effects than intraannual variability. Further, the effect of precipitation variability was modulated by mean annual precipitation. Arid-semiarid locations receiving less than about 380 mm yr-1 mean annual precipitation showed increases in water availability as a result of enhanced precipitation variability while more mesic locations (\>380 mm yr-1) showed a decrease in soil water availability. The beneficial effects of enhanced variability in arid-semiarid regions resulted from a deepening of the soil-water availability profile and a reduction in bare soil evaporation. The deepening of the soil-water availability profile resulting from increase precipitation variability may promote future shifts in species composition and dominance to deeper-rooted woody plants for ecosystems that are susceptible to state changes. The break point, which has a mean of 380-mm with a range between 440 and 350 mm, is remarkably similar to the 370-mm threshold of the inverse texture hypothesis, below which coarse-texture soils had higher productivity than fine-textured soils.

}, keywords = {climate change, drought, model, precipitation variability, rainfall variability, soil-water availability}, doi = {10.1007/s10584-015-1389-z}, url = {/files/bibliography/15-013.pdf}, author = {O. E. Sala and Laureano A. Gherardi and Debra C. Peters} } @proceedings {JRN54535, title = {Effects of interannual precipitation variability on ecosystem water balance and its consequences for aboveground net primary production}, volume = {OOS 12-6}, year = {2012}, month = {08/2012}, publisher = {Ecological Society of America Abstracts}, address = {Portland, Oregon}, abstract = {Climate change will result in an increase in the variability of precipitation within and among years as a result of different atmospheric phenomena. For many locations, there will be larger precipitation events interspersed with longer periods of droughts within a year, and more sequences of extreme dry years followed by multi-year extremely wet periods. Here, we focused on the inter-annual scale and hypothesize that increased inter-annual variability in precipitation will differentially affect the major components of water loss from arid to subhumid ecosystems. We expect this variability will have consequences for the amount of water available to plants for primary production. We tested our hypothesis using the model SOILWAT parameterized for arid (Jornada Basin) and mesic (Konza Prairie) grassland sites in the US. SOILWAT is a multi-layer, daily time-step model that simulates soil water content by depth in the soil profile. We increased precipitation variability at the inter-annual scale by randomly adding or subtracting a percentage of daily precipitation for each year in the 100-year record. Thus, total precipitation was the same as the control simulations, but the variability was 25\% higher. We repeated the exercise for 25, 50, 75, and 100\% increased variability. Our results show that increased interannual precipitation variability increased plant available water in the arid site and decreased it in the mesic site. High variability resulted in a high frequency of large rainfall events, which in turn resulted in a downward shift of the distribution of water availability in the soil profile that reduced bare-soil evaporative losses and enhanced deep percolation losses. Therefore, an increase in variability decreased losses in arid ecosystems where losses occurred predominantly via bare-soil evaporation. On the contrary, increased precipitation variability increased losses in the mesic ecosystem, where major losses occurred via deep percolation. Given the tight relationship that exists between transpiration and photosynthesis, we expect that an increase in precipitation interannual variability will increase productivity in the arid site and reduce it in the mesic site.}, author = {O. E. Sala and Laureano A. Gherardi and Debra C. Peters} } @article {49902, title = {Legacies of precipitation fluctuations on primary production: theory and data synthesis}, journal = {Philosophical Transactions of the Royal Society B}, volume = {367}, year = {2012}, month = {08/2012}, pages = {3135-3144}, chapter = {3135}, abstract = {Variability of above-ground net primary production (ANPP) of arid to sub-humid ecosystems displays a closer association with precipitation when considered across space (based on multiyear averages for different locations) than through time (based on year-to-year change at single locations). Here, we propose a theory of controls of ANPP based on four hypotheses about legacies of wet and dry years that explains space versus time differences in ANPP\–precipitation relationships. We tested the hypotheses using 16 long-term series of ANPP. We found that legacies revealed by the association of current- versus previous-year conditions through the temporal series occur across all ecosystem types from deserts to mesic grasslands. Therefore, previous-year precipitation and ANPP control a significant fraction of current-year production. We developed unified models for the controls of ANPP through space and time. The relative importance of current-versus previous-year precipitation changes along a gradient of mean annual precipitation with the importance of current-year PPT decreasing, whereas the importance of previous-year PPT remains constant as mean annual precipitation increases. Finally, our results suggest that ANPP will respond to climate-change-driven alterations in water availability and, more importantly, that the magnitude of the response will increase with time.}, keywords = {legacies, precipitation effects, primary production, spatial and temporal models}, doi = {10.1098/rstb.2011.0347}, url = {/files/bibliography/12-039.pdf}, author = {O. E. Sala and Laureano A. Gherardi and Lara Reichmann and Esteban Jobb{\'a}gy and Debra C. Peters} } @inbook {49991, title = {Grassland ecosystems}, booktitle = {Encyclopedia of Biodiversity}, year = {2011}, publisher = {Elsevier}, organization = {Elsevier}, keywords = {biodiversity, grassland ecosystems}, author = {O. E. Sala and L. Vivanco and P. Flombaum} } @inbook {50279, title = {Changes in biodiversity and their consequences for human health}, booktitle = {Biodiversity change and human health: from ecosystem services to spread of disease}, year = {2008}, note = {//OTHER//LTER-V//entered 06/02/2008 per DEPProCite field[6]: In}, month = {2008}, publisher = {Island Press}, organization = {Island Press}, address = {Washington, DC}, keywords = {biodiversity, book, chapter, disease, ecosystem services, human health, report}, author = {O. E. Sala and Meyerson, L. A. and C. Parmesan}, editor = {O. E. Sala and Meyerson, L. A. and C. Parmesan} } @article {50501, title = {Determinants of biodiversity change: ecological tools for building scenarios}, journal = {Ecology}, volume = {87}, year = {2006}, note = {//Other//LTER-V//entered 08/15/2007}, month = {2006}, pages = {1875-1876}, abstract = {

As defined in the recent Millenium Ecosystem Assessment (MA), biodiversity scenarios are "plausible alternative futures." They do not attempt to predict the precise future state of biodiversity, but rather they identify the consequences of the different paths that human society may follow for biodiversity. Scenarios are designed to assist decision makers by identifying costs and benefits, in terms of biodiversity, of alternative actions. Within the framework of the MA, the first stage in developing biodiversity scenarios was to identify the major drivers of biodiversity change in the next 50{\textendash}100 years. Land-use change, climate change, and nutrient enrichment were identified as the major drivers of biodiversity change in terrestrial and freshwater ecosystems. The next steps in constructing successful biodiversity scenarios are (1) assessing changes in drivers of different socioeconomic scenarios and (2) developing the algorithms that relate changes in drivers with changes in biodiversity. This Special Feature focuses on a key component of the second of these two steps: evaluating the current tools used by ecologists to develop scenarios based on changes in drivers of biodiversity change.

}, keywords = {article, biodiversity losses, biodiversity scenario, biodiversity, freshwater, biodiversity, river discharge, ecosystem services, global scenarios, journal, land-use change, model, MA, model, Millenium Ecosystem Assessment}, doi = {10.1890/0012-9658(2006)87\%5B1875:DOBCET\%5D2.0.CO;2}, url = {files/bibliography/JRN00441.pdf}, author = {O. E. Sala and R. B. Jackson} } @article {51113, title = {Global biodiversity scenarios for the year 2100}, journal = {Science}, volume = {287}, year = {2000}, note = {//?//LTER III//}, month = {2000}, pages = {1770}, abstract = {

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

}, keywords = {article, articles, biodiversity, global, journal, journals}, doi = {10.1126/science.287.5459.1770 }, url = {files/bibliography/JRN00301.pdf}, author = {O. E. Sala and L. Huenneke} }