Two of the most pervasive human impacts on ecosystems are alteration of global nutrient budgets and changes in the abundance and identity of consumers. Fossil fuel combustion and agricultural fertilization have doubled and quintupled, respectively, global pools of nitrogen and phosphorus relative to pre-industrial levels. In spite of the global impacts of these human activities, there have been no globally coordinated experiments to quantify the general impacts on ecological systems. This experiment seeks to determine how nutrient availability controls plant biomass, diversity, and species composition in a desert grassland. This has important implications for understanding how future atmospheric deposition of nutrients (N, S, Ca, K) might affect community and ecosystem-level responses. This study is part of a larger coordinated research network that includes more than 40 grassland sites around the world. By using a standardized experimental setup that is consistent across all study sites, we are addressing the questions of whether diversity and productivity are co-limited by multiple nutrients and if so, whether these trends are predictable on a global scale.Above-ground net primary production is the change in plant biomass, represented by stems, flowers, fruit and and foliage, over time and incoporates growth as well as loss to death and decomposition. To measure this change the vegetation variables, including species composition and the cover and height of individuals, are sampled twice yearly (spring and fall) at permanent 1m x 1m plots within each site. Volumetric measurements are made using vegetation data from permanent plots (SEV231, "Effects of Multiple Resource Additions on Community and Ecosystem Processes: NutNet NPP Quadrat Sampling") and regressions correlating species biomass and volume constructed using seasonal harvest weights from SEV157, "Net Primary Productivity (NPP) Weight Data."
Knowledge Network for Biocomplexity (KNB) Identifier
Data Policies: This dataset is released to the public and may be freely downloaded. Please keep the designated Contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement of the Sevilleta LTER. Datasets must be cited as in the example provided. A copy of any publications using these data must be supplied to the Sevilleta LTER Information Manager. By downloading any data you implicitly acknowledge the LTER Data Policy (http://www.lternet.edu/data/netpolicy.html).
2008-05-13 - 2012-01-10
Location: Deep Well is located on McKenzie Flats and is site of the longest running SEV LTER met station, number 40, which has been active since 1988. In addition to studies of meteorological variables, core line-intercept vegetation transects and line-intercept transects from the 1995 and 2001 Deep Well fires are sampled here. The mini-rhizotron study, blue and black grama compositional comparison, blue and black grama patch dynamics investigation, and kangaroo rat population assessement are all ongoing here. Deep Well Blue/Black Grama Mixed is also the location of the warming and monsoon experiments, as well as portions of the line-intercept and vegetation removal studies. On August 4, 2009, a lightning-initiated fire began on the Sevilleta National Wildlife Refuge. By August 5, 2009, the fire had reached the area of Deep Well Blue/Black Grama Mixed. While portions of this site were burned, the entirety was not. See individual projects for further information on the effects of the fire.Vegetation: The vegetation of Deep Well Blue/Black Grama Mixed is Chihuahuan Desert Grassland, dominated by black grama (Bouteloua eriopoda) and blue grama (B. gracilis). Other grasses found at the site include dropseeds (Sporobolus spp.) and threeawns (Aristida spp.). Shrubs are uncommon but those that occur include Yucca glauca, Ephedra torreyi, and four-wing saltbush (Atriplex canescens). Herbaceous plants include Plantago purshii, Hymenopappus filifolius, and globe mallows (Sphaeralcea spp.).
Collins, Scott (2015): Effects of Multiple Resource Additions on Community and Ecosystem Processes: NutNet Seasonal Biomass and Seasonal and Annual NPP Data at the Sevilleta National Wildlife Refuge, New Mexico. Long Term Ecological Research Network. http://dx.doi.org/10.6073/pasta/5fee5a4260ad2e8848e24dce87c12efa