Persistence of desertified ecosystems: Explanations and implications

TitlePersistence of desertified ecosystems: Explanations and implications
Publication TypeConference Proceedings
Year of Publication1995
AuthorsWhitford WG, Martinez-Turanzas G, Martinez-Meza E
EditorMouat DA, Hutchinson CF(eds.)
Conference NameDesertification in developed countries
VolumeReprinted from Environmental Monitoring and Assessment, Volume 37, Nos. 1-3, 1995
Number of Volumes363
Pagination319-332
Date PublishedOctober 24-29, 1
PublisherKluwer Academic Publishers
Conference LocationTucson, Arizona
ISBN Number0-7923-3919-3
Accession NumberJRN00194
Call NumberN0002
Keywordsabstract, abstracts, conference, conference proceedings, conferences, desertification, shrubs, desertification,Prosopis dunelands, herbicide impact, Prosopis duneland, proceeding, proceedings, rainfall simulation,Larrea, shrub, desertification, shrub, stemflow, stemflow, shrub
Abstract Studies of rainfall partitioning by shrubs, responses of shrub-dominated ecosystems to herbicide treatment, and experiments using drought and supplemental rainfall were done to test the hypothesis that the shrub-dominated ecosystems that have replaced desert grasslands are resistant and resilient to disturbance. Between 16 and 25% of the intercepted rainfall is channelized to deep soil storage by stemflow and root channelization. Stemflow water is nutrient enriched and contributes to the "islands of fertility" that develop under desert shrubs. Drought and rainfall augmentation experiments during the growing season after 5 consectuvie years of summer drought found that (1) growth of creosotebushes, Larrea tridentata, was not significantly affected, (2) perennial grasses and forbs disappeared on droughted plots, (3) nitrogen mineralization increased in the short term, and (4) densities and biomass of spring annual plants increased on the droughted plots. Doubling summer rainfal for 5 consecutive years had less-significant effects. Coppice dunes treated with herbicide in 1979 to kill mesquite (Prosopis glandulosa) had the same frequency of occurrence of the shrub as the untreated dunes when remeasured in 1993. These data indicate that the shrub-dominated ecosystems persist because they are resistant and resilient to climatic and anthropogenic stresses.
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