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Titolo:
TREE-GRASS DYNAMICS IN A PROSOPIS-THORNSCRUB SAVANNA PARKLAND - RECONSTRUCTING THE PAST AND PREDICTING THE FUTURE
Autore:
ARCHER S;
Indirizzi:
TEXAS A&M UNIV,DEPT RANGELAND ECOL & MANAGEMENT COLLEGE STN TX 77843
Titolo Testata:
Ecoscience
fascicolo: 1, volume: 2, anno: 1995,
pagine: 83 - 99
SICI:
1195-6860(1995)2:1<83:TDIAPS>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
WOODY PLANT INVASION; SUBTROPICAL SAVANNA; SHRUB INVASION; ARID SAVANNA; SOUTH TEXAS; VEGETATION; FOREST; SUCCESSION; PRAIRIE; GLANDULOSA;
Keywords:
BOUNDARIES; COMPETITION; FACILITATION; PROSOPIS GLANDULOSA; SOIL DELTA(13); SUCCESSION;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
134
Recensione:
Indirizzi per estratti:
Citazione:
S. Archer, "TREE-GRASS DYNAMICS IN A PROSOPIS-THORNSCRUB SAVANNA PARKLAND - RECONSTRUCTING THE PAST AND PREDICTING THE FUTURE", Ecoscience, 2(1), 1995, pp. 83-99

Abstract

Although trends toward increased woody plant abundance in grasslands and savannas in recent history have been reported worldwide, our understanding of the processes involved is limited. Here I review and integrate a series of studies which quantify the rates, dynamics, spatial patterns and successional processes involved in tree patch and woody plant community development at a savanna parkland site in southern Texas, U.S.A. Stable carbon isotope ratios of soil organic carbon indicate C-3 woody plants currently occupy sites once dominated by C-4 grasses. Historical aerial photographs (1941-1990), tree ring analysis and plant growth models all indicate this displacement has occurred over the past 100 to 200 years. Succession from grass- to woody plant-domination occurs when the N-2-fixing arborescent, honey mesquite (Prosopis glandulosa (Torr.) var. glandulosa), invades and establishes in herbaceous patches. Over time, this plant modifies soils and microclimate to facilitate the ingress and establishment of additional woody species. The result is a landscape comprised of shrub clusters of varying ages organized around a Prosopis nucleus. As new clusters form and existing clusters enlarge, coalescence occurs. This process appears to be in progress on upland portions of the landscape and has progressed to completion on lowlands. Rates of cluster development and patterns of distribution appear regulated by subsurface variations in clay content and byvariations in annual rainfall. Simulation models based on reconstructions and forward projections indicate succession from grassland to woodland steady states would require 400-500 years, with the most dramatic changes occurring over a 200-year period. The shrubs initially facilitated by Prosopis appear to contribute to its demise and prevent its re-establishment. Structure and function of future communities may therefore depend on how remaining woody plants react to changes in microclimate and nitrogen cycling that occur after Prosopis is gone.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 00:26:19