Date
2012
Abstract
The distribution, structure and function of mesic savanna grasslands are strongly driven by fire regimes, grazing by large herbivores, and their interactions. This research addresses a general question about our understanding of savanna grasslands globally: Is our knowledge of fire and grazing sufficiently general to enable us to make accurate predictions of how these ecosystems will respond to changes in these drivers over time? Some evidence suggests that fire and grazing influence savanna grassland structure and function differently in South Africa (SA) compared to North America (NA). These differences have been attributed to the contingent factors of greater biome age, longer evolutionary history with fire and grazing, reduced soil fertility, and greater diversity of plants and large herbivores in SA. An alternative hypothesis is that differences in methods and approaches used to study these systems have led to differing perspectives on the role of these drivers. If the impacts of shared ecosystem drivers truly differ between NA and SA, this calls into question the generality of our understanding of these ecosystems and our ability to forecast how changes in key drivers will affect savanna grasslands globally. Since 2006, an explicitly comparative research program has been conducted to determine the degree of convergence in ecosystem (productivity, N and C cycling) and plant community (composition, diversity, dynamics) responses to fire and grazing in SA and NA. Thus far, initial support has been found for convergence at the ecosystem level and divergence at the community level in response to alterations in both fire regimes and grazing. However, there have also been two unexpected findings (1) the ways in which fire and grazing interact differed between NA and SA, and (2) the rate of change in communities when grazers were removed was much greater in NA than in SA. These unexpected findings raise a number of important new questions: (Q1) Will exclusion of grazing eventually affect community structure and composition across all fire regimes in SA? (Q2) Will these effects differ from those observed in NA? (Q3) What are the determinants of the different rates of community change? (Q4) How will these determinants influence future trajectories of change? (Q5) Will the different rates and trajectories of community change be mirrored by responses in ecosystem function over time? This project is based on a large herbivore exclusion study established within the context of long-term (25-50+ yr) experimental manipulations of fire frequency at the Konza Prairie Biological Station (KPBS) in NA and the Kruger National Park (KNP) in SA. The suite of core studies and measurements include plant community composition, ANPP, and herbivore abundance and distribution at both study sites to answer these research questions.
Handle
http://hdl.handle.net/1928/29961.1
Other Identifier
SEV264
Knowledge Network for Biocomplexity (KNB) Identifier
knb-lter-sev.264.161080
Document Type
Dataset
Rights
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).
Source
http://dx.doi.org/10.6073/pasta/0075b5e92e0c4d9248e6336592b9dd55
Temporal coverage
2005-01-01 - 2012-03-06
DOI
doi:10.6073/pasta/0075b5e92e0c4d9248e6336592b9dd55
Permanent URL
http://dx.doi.org/10.6073/pasta/0075b5e92e0c4d9248e6336592b9dd55
Recommended Citation
Knapp, Alan; Smith, Melinda; Blair, John; Collins, Scott; Burkepile, Deron; Kirkman, Kevin: Konza Prairie, Kansas Plant Species List. Long Term Ecological Research Network. http://dx.doi.org/10.6073/pasta/0075b5e92e0c4d9248e6336592b9dd55
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knb-lter-sev.264.161080-provenance.xml (6 kB)
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knb-lter-sev.264.161080-report.html (28 kB)
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sev264_konzaspplist_03062012.txt (15 kB)
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Comments
This dataset was originally published on the Long Term Ecological Research (LTER) Network Data Portal, https://portal.lternet.edu, and potentially via other repositories or portals as described. The Digital Object Identifier (DOI) of the source data package is doi:10.6073/pasta/0075b5e92e0c4d9248e6336592b9dd55, and may be accessed at http://dx.doi.org/10.6073/pasta/0075b5e92e0c4d9248e6336592b9dd55. Metadata and files included in this record mirror as closely as possible the source data and documentation, with the provenance metadata and quality report generated by the LTER portal reproduced here as '*-provenance.xml' and *-report.html' files, respectively.