Detection of process-related changes in plant patterns at extended spatial scales during early dryland desertification

被引:38
作者
Ares, J [1 ]
Del Valle, H [1 ]
Bisigato, A [1 ]
机构
[1] Natl Patagon Ctr, RA-9120 Puerto Madryn, Argentina
关键词
desertification; drylands; Patagonia; remote sensing; spatial-explicit models; spatial vegetation patterns; wind erosion;
D O I
10.1046/j.1365-2486.2003.00690.x
中图分类号
X176 [生物多样性保护];
学科分类号
090705 ;
摘要
Arid and semiarid shrublands occupy extensive land areas over the world, are susceptible to desertification by anthropic use and can contribute to regional climate change. These prompt the interest to monitor and evaluate these lands adequately in order to detect early stages of degradation. Evaluation topics must refer to biology-relevant characteristics of these systems, while simultaneously satisfying sampling consistency over extended landscape areas. We present an analysis of process-relevant parameters related to changes in the spatial arrangement of the plant canopy of shrublands inferred from high-resolution panchromatic aerial photos and Interferometric Synthetic Aperture Radar imagery. We obtained low-altitude images systematically located along several gradients of land-use intensity in a Patagonian Monte shrubland in Argentina. Images were digitized to spatial resolutions ranging from 0.09 to 0.72 m (pixel size) and the average values and an-isotropic characteristics of the plant canopy patterns were quantified by means of a Fourier metric. We used radar-derived imagery to overlay the panchromatic images on a digital elevation model in order to study the correspondence of potential runoff patterns and the spatial arrangement of plants. We related an-isotropic features of the plant canopy images to the prevailing wind regime. Observed trends were further interpreted on the basis of a spatial-explicit simulation model describing the dynamics of the main functional groups in the plant community. We conclude that early stages of anthropic-driven dryland degradation in the Patagonian Monte can be characterized by the incipient un-coupling of spatial vegetation patterns from those of runoff at a landscape scale, and a progressive coupling to the spatial pattern of the wind regime. The method and metrics we present can be used to quantify early desertification changes in other similar drylands at extended spatial scales.
引用
收藏
页码:1643 / 1659
页数:17
相关论文
共 54 条
[1]   The effect of grazing on the spatial heterogeneity of vegetation [J].
Adler, PB ;
Raff, DA ;
Lauenroth, WK .
OECOLOGIA, 2001, 128 (04) :465-479
[2]   Grass-mediated capture of resource flows and the maintenance of banded mulga in a semi-arid woodland [J].
Anderson, VJ ;
Hodgkinson, KC .
AUSTRALIAN JOURNAL OF BOTANY, 1997, 45 (02) :331-342
[3]  
[Anonymous], 1988, J ARID ENVIRON
[4]   Modeling and measurement of structural changes at a landscape scale in dryland areas [J].
Ares, J ;
Bertiller, M ;
Bisigato, A .
ENVIRONMENTAL MODELING & ASSESSMENT, 2003, 8 (01) :1-13
[5]   Estimates of dryland degradation in Argentina with Fourier signatures from low-altitude monochromatic images with high spatial resolution [J].
Ares, JO ;
Bertiller, MB ;
Bisigato, A .
LANDSCAPE ECOLOGY, 2003, 18 (01) :51-63
[6]  
ARES JO, 1990, MANAGED GRASSLANDS R, P268
[7]  
Baker WL, 1989, LANDSCAPE ECOL, V2, P112
[8]   ECOSYSTEM CHANGES ASSOCIATED WITH GRAZING INTENSITY ON THE PUNTA-NINFAS RANGELANDS OF PATAGONIA, ARGENTINA [J].
BEESKOW, AM ;
ELISSALDE, NO ;
ROSTAGNO, CM .
JOURNAL OF RANGE MANAGEMENT, 1995, 48 (06) :517-522
[9]   Magnitude-frequency analysis of water redistribution along a climate gradient in Spain [J].
Bergkamp, G ;
Cerdà, A ;
Imeson, AC .
CATENA, 1999, 37 (1-2) :129-146
[10]   Multiscale indicators of land degradation in the Patagonian Monte, Argentina [J].
Bertiller, MB ;
Ares, JO ;
Bisigato, AJ .
ENVIRONMENTAL MANAGEMENT, 2002, 30 (05) :704-715