The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa

 

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dc.contributor.author Cramer, Michael D en_ZA
dc.contributor.author Hoffman, M Timm en_ZA
dc.date.accessioned 2015-12-20T16:08:29Z
dc.date.available 2015-12-20T16:08:29Z
dc.date.issued 2015 en_ZA
dc.identifier.citation Cramer, M. D., & Hoffman, M. T. (2015). The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa. PloS one, 10(12). doi:10.1371/journal.pone.0144512 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/15932
dc.identifier.uri http://dx.doi.org/10.1371/journal.pone.0144512
dc.description.abstract Globally, mediterranean-climate ecosystem vegetation has converged on an evergreen, sclerophyllous and shrubby growth form. The particular aspects of mediterranean-climate regions that contribute to this convergence include summer droughts and relatively nutrient-poor soils. We hypothesised that winter-precipitation implies stressful summer droughts and leaches soils due to greater water availability (i.e. balance between precipitation and potential evapotranspiration; P-PET) during cold periods. We conducted a comparative analysis of normalised difference vegetation indices (NDVI) and edaphic and climate properties across the biomes of South Africa. NDVI was strongly correlated with both precipitation and P-PET (r 2 = 0.8). There was no evidence, however, that winter-precipitation reduces NDVI in comparison to similar amounts of summer-precipitation. Base saturation (BS), a measure of soil leaching was, however, negatively related to P-PET (r 2 = 0.64). This led to an interaction between P-PET and BS in determining NDVI, indicating the existence of a trade-off between water availability and soil nutrients that enables NDVI to increase with precipitation, despite negative consequences for soil nutrient availability. The mechanism of this trade-off is suggested to be that water increases nutrient accessibility. This implies that along with nutrient-depauperate geologies and long periods of time since glaciation, the winter-precipitation may have contributed to the highly leached status of the soils. Since many of the ecophysiological characteristics of mediterranean-ecosystem flora are associated with low nutrient availabilities (e.g. evergreen foliage, sclerophylly, cluster roots), we conclude that mediterranean-climates promote convergence of growth-forms in these regions through high leaching capacity. en_ZA
dc.language.iso eng en_ZA
dc.publisher Public Library of Science en_ZA
dc.rights This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. en_ZA
dc.rights.uri http://creativecommons.org/licenses/by/4.0 en_ZA
dc.source PLoS One en_ZA
dc.source.uri http://journals.plos.org/plosone en_ZA
dc.subject.other Ecosystems en_ZA
dc.subject.other Grasslands en_ZA
dc.subject.other Rain en_ZA
dc.subject.other South Africa en_ZA
dc.subject.other Summer en_ZA
dc.subject.other Winter en_ZA
dc.subject.other Cation exchange capacity en_ZA
dc.subject.other Water resources en_ZA
dc.title The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa en_ZA
dc.type Journal Article en_ZA
dc.rights.holder © 2015 Cramer, Hoffman en_ZA
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Cramer, M. D., & Hoffman, M. T. (2015). The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa. <i>PLoS One</i>, http://hdl.handle.net/11427/15932 en_ZA
dc.identifier.chicagocitation Cramer, Michael D, and M Timm Hoffman "The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa." <i>PLoS One</i> (2015) http://hdl.handle.net/11427/15932 en_ZA
dc.identifier.vancouvercitation Cramer MD, Hoffman MT. The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa. PLoS One. 2015; http://hdl.handle.net/11427/15932. en_ZA
dc.identifier.ris TY - Journal Article AU - Cramer, Michael D AU - Hoffman, M Timm AB - Globally, mediterranean-climate ecosystem vegetation has converged on an evergreen, sclerophyllous and shrubby growth form. The particular aspects of mediterranean-climate regions that contribute to this convergence include summer droughts and relatively nutrient-poor soils. We hypothesised that winter-precipitation implies stressful summer droughts and leaches soils due to greater water availability (i.e. balance between precipitation and potential evapotranspiration; P-PET) during cold periods. We conducted a comparative analysis of normalised difference vegetation indices (NDVI) and edaphic and climate properties across the biomes of South Africa. NDVI was strongly correlated with both precipitation and P-PET (r 2 = 0.8). There was no evidence, however, that winter-precipitation reduces NDVI in comparison to similar amounts of summer-precipitation. Base saturation (BS), a measure of soil leaching was, however, negatively related to P-PET (r 2 = 0.64). This led to an interaction between P-PET and BS in determining NDVI, indicating the existence of a trade-off between water availability and soil nutrients that enables NDVI to increase with precipitation, despite negative consequences for soil nutrient availability. The mechanism of this trade-off is suggested to be that water increases nutrient accessibility. This implies that along with nutrient-depauperate geologies and long periods of time since glaciation, the winter-precipitation may have contributed to the highly leached status of the soils. Since many of the ecophysiological characteristics of mediterranean-ecosystem flora are associated with low nutrient availabilities (e.g. evergreen foliage, sclerophylly, cluster roots), we conclude that mediterranean-climates promote convergence of growth-forms in these regions through high leaching capacity. DA - 2015 DB - OpenUCT DO - 10.1371/journal.pone.0144512 DP - University of Cape Town J1 - PLoS One LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa TI - The consequences of precipitation seasonality for Mediterranean-ecosystem vegetation of South Africa UR - http://hdl.handle.net/11427/15932 ER - en_ZA


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This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Except where otherwise noted, this item's license is described as This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.