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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVED PLANT GENETIC RESOURCES FOR PASTURES AND RANGELANDS IN THE TEMPERATE SEMIARID REGIONS OF THE WESTERN U.S. Title: Long-term redevelopment of resource islands in shrublands of the Great Basin, USA

Authors
item Morris, Lesley -
item Monaco, Thomas
item Blank, Robert
item Sheley, Roger

Submitted to: Ecosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 27, 2012
Publication Date: January 1, 2013
Citation: Morris, L.R., Monaco, T.A., Blank, R.R., Sheley, R.L. 2013. Long-term redevelopment of resource islands in shrublands of the Great Basin, USA. Ecosphere. 4:12.

Interpretive Summary: Soil resource availability in semi-arid and arid shrubland ecosystems is highly heterogeneous and includes patterns of resource accumulation primarily beneath shrubs as opposed to shrub interspaces. These resource islands contribute to ecosystem resilience after natural disturbances such as fire, yet very little is known regarding their redevelopment following soil disturbance and shrub re-colonization. Cultivation involves the removal of native vegetation and mixing of soils both vertically and horizontally. The old fields in this study offered a unique look at the long-term redevelopment of resource islands under shrubs where cultivation was abandoned nearly a century ago. Using adjacent pairs of previously cultivated and native shrubland from three soil series, we sampled surface soils (0-5 cm) in microsites under shrubs and in the interspaces between them to examine if soil fertility (C, N, P, Ca, Mg, K) had regained similar microsite patchiness to the native shrubland, if the values of each soil fertility measure were different, and if the microsites under shrubs were still distinct from non-disturbed microsites. We found that while most of the resource island patterning had redeveloped, the content of each fertility measure had not recovered to pre-disturbance levels. Further, the recovery was different between the soil series and between dominant shrub species. There were also differences between sites within the same soil series, suggesting that historical cultivation practices may influence resource island recovery in multiple ways. Overall, under-shrub microsites in previously cultivated areas were still distinct from comparable under-shrub microsites in native areas in two out of the three soil series. These findings suggest that it may take over a century for resource islands to fully re-establish in formerly cultivated soils.

Technical Abstract: Soil resource availability in semi-arid and arid shrubland ecosystems is highly heterogeneous and includes patterns of resource accumulation primarily beneath shrubs as opposed to shrub interspaces. These resource islands contribute to ecosystem relience after natural disturbances such as fire, yet very little is known regarding their redevelopment following soil disturbance and shrub re-colonization. Cultivation involves the removal of native vegetation and mixing of soils both vertically and horizontally. The old fields in this study offered a unique look at the long-term redevelopment of resource islands under shrubs where cultivation was abandoned nearly a century ago. Using adjacent pairs of previously cultivated and native shrubland from three soil series, we sampled surface soils (0-5 cm) in microsites under shrubs and in the interspaces between them to examine if soil fertility (C, N, P, Ca, Mg, K) had regained similar microsite patchiness to the native shrubland, if the values of each soil fertility measure were different, and if the microsites under shrubs were still distinct from non-disturbed microsites. We found that while most of the resource island patterning had redeveloped, the content of each fertility measure had not recovered to pre-disturbance levels. Further, the recovery was different between the soil series and between dominant shrub species. There were also differences between sites within the same soil series, suggesting that historical cultivation practices may influence resource island recovery in multiple ways. Overall, under-shrub microsites in previously cultivated areas were still distinct from comparable under-shrub microsites in native areas in two out of the three soil series. These findings suggest that it may take over a century for resource islands to fully re-establish in formerly cultivated soils.

Last Modified: 12/28/2014
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