Findings of the Global Desertification Assessment by the Millennium Ecosystem Assessment – A Perspective for Better Managing Scientific Knowledge

Adeel, Zafar

doi:10.1007/978-1-4020-6970-3_57

Cited by 19 publications

(18 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Huenneke et al 2002;Jackson et al 2002;Bestelmeyer 2005;Duval & Whitford 2008;Eldridge et al 2009) and South Africa (e.g. Adeel 2008;Sankaran & Anderson 2009). The term ÔdesertificationÕ has been widely (and loosely) applied and has now been invoked to describe almost any compositional or successional changes in dryland vegetation that are regarded by society in a negative sense, at least in the context of pastoralism.…”

Section: Is Encroachment Synonymous With Degradation or Desertification?mentioning

confidence: 99%

“…In Australia, extensive areas of semi-arid woodland are now occupied by native shrubs at higher densities than thought to exist prior to European settlement (Noble 1997). In southern Africa, 13 million hectares are subject to bush encroachment (Trollope et al 1989), and, along with the loss of savanna systems, are believed to affect more than two billion people worldwide (Adeel 2008). In the Mediterranean Basin, encroachment seems to be associated with the cessation of sheep grazing and activities related to grass fibre cultivation and woody fuel extraction (Maestre et al 2009), and with the natural regeneration of oak woodlands (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis

et al. 2011

View full text Add to dashboard Cite

Encroachment of woody plants into grasslands has generated considerable interest among ecologists. Syntheses of encroachment effects on ecosystem processes have been limited in extent and confined largely to pastoral land uses or particular geographical regions. We used univariate analyses, meta-analysis and structural equation modelling to test the propositions that (1) shrub encroachment does not necessarily lead to declines in ecosystem functions and (2) shrub traits influence the functional outcome of encroachment. Analyses of 43 ecosystem attributes from 244 case studies worldwide showed that some attributes consistently increased with encroachment (e.g. soil C, N), and others declined (e.g. grass cover, pH), but most exhibited variable responses. Traits of shrubs were associated with significant, though weak, structural and functional outcomes of encroachment. Our review revealed that encroachment had mixed effects on ecosystem structure and functioning at global scales, and that shrub traits influence the functional outcome of encroachment. Thus, a simple designation of encroachment as a process leading to functionally, structurally or contextually degraded ecosystems is not supported by a critical analysis of existing literature. Our results highlight that the commonly established link between shrub encroachment and degradation is not universal.

show abstract

Section: Is Encroachment Synonymous With Degradation or Desertification?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Additional data are needed to interpret low LNS, particularly with field observation. Given the extremely large areas of provincial, national, regional, and global degradation that are frequently stated (Bai et al, 2008;Bridges and Oldeman, 1999;Kassas, 1995;Oldeman, 1994;UNEP, 1997;Zika and Erb, 2009) and the far-reaching effects of degradation on human livelihoods (Adeel, 2008;UNCCD, 1994), rigorous, quantitative, and objective measurements are urgently needed. While reduction of NPP is a single type of degradation, it is a quantitative measure of the outcome of most forms of degradation relevant to human needs -but not all (e.g., loss of palatable species with no change in NPP; Asner and Heidebrecht, 2005).…”

Section: Anthropogenic and Environmental Degradationmentioning

confidence: 99%

Degradation of net primary production in a semiarid rangeland

Jackson

Prince

2016

Biogeosciences

View full text Add to dashboard Cite

Abstract. Anthropogenic land degradation affects many biogeophysical processes, including reductions of net primary production (NPP). Degradation occurs at scales from small fields to continental and global. While measurement and monitoring of NPP in small areas is routine in some studies, for scales larger than 1 km 2 , and certainly global, there is no regular monitoring and certainly no attempt to measure degradation. Quantitative and repeatable techniques to assess the extent of deleterious effects and monitor changes are needed to evaluate its effects on, for example, economic yields of primary products such as crops, lumber, and forage, and as a measure of land surface properties which are currently missing from dynamic global vegetation models, assessments of carbon sequestration, and land surface models of heat, water, and carbon exchanges. This study employed the local NPP scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland, Australia, from 2000 to 2013. The method starts with land classification based on the environmental factors presumed to control (NPP) to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference in units of mass of carbon and percentage loss were the measure of degradation. The entire BDT (7.45 × 10 6 km 2 ) was investigated at a spatial resolution of 250 × 250 m. The average annual reduction in NPP due to anthropogenic land degradation in the entire BDT was −2.14 MgC m −2 yr −1 , or 17 % of the non-degraded potential, and the total reduction was −214 MgC yr −1 . Extreme average annual losses of 524.8 gC m −2 yr −1 were detected. Approximately 20 % of the BDT was classified as "degraded". Varying severities and rates of degradation were found among the river basins, of which the Belyando and Suttor were highest. Interannual, negative trends in reductions of NPP occurred in 7 % of the entire region, indicating ongoing degradation. There was evidence of areas that were in a permanently degraded condition. The findings provide strong evidence and quantitative data for reductions in NPP related to anthropogenic land degradation in the BDT.

show abstract

“…Arid zones, which make up about 30 percent of China's total territory, are areas characterized by sparse vegetation, shortage of water resources, and fragile environment [1]. The oasis-desert ecotone plays an important ecological role in the arid region.…”

Section: Introductionmentioning

confidence: 99%

Spatial Analysis of a Haloxylon Ammodendron Plantation in an Oasis-Desert Ecotone in the Hexi Corridor, Northwestern China

Zhao

Zhang

2017

Forests

View full text Add to dashboard Cite

Abstract:Haloxylon ammodendron is a commonly used sand-fixing species in the desert area of northwestern China; it has been abundantly planted in areas where annual precipitation is about 120 mm in the Hexi Corridor since the 1970s. Spatial patterns and associations of an H. ammodendron plantation in five stages of community development were analyzed in an oasis-desert ecotone to gain insights into population dynamics over a course of succession. Five 0.3-ha (50 m × 60 m) permanent plots were established in each of five developmental stages; H. ammodendron was classified as seedlings, juvenile and mature trees, and all individuals were measured and stem-mapped. The univariate spatial analysis by the L-function and the bivariate L 12 -function were used to describe the spatial patterns of all trees and examine the spatial association among trees between different tree size-classes. Results showed that at scales >2 m, the spatial pattern of H. ammodendron shifted from initially clustered to random, and back to clustered; at scales <2 m, a transition from uniform to clustered was observed with stand age. In 5-10-year, 10-20-year and 20-30-year stages, competition between conspecifics may be the dominant factor which influenced plant survival. In 30-40-year and >40-year stages, interactions between conspecifics may be the dominant factor in conditions of tree-size-asymmetric competition, but abiotic stress may be more important in tree-size-symmetric competition. The H. ammodendron plantation experienced highest mortality at the 5-10-year stage as a result of fierce competition for soil water, while with respect to growth, it entered into a relatively stable stage, where the gaps generated due to mortality of adult trees and improved soil conditions provided opportunities for regeneration. In the >40-year stage, the regeneration experienced a decline under enhanced competition for water, and the plantation showed a clustered pattern at all scales due to water stress.

show abstract

Findings of the Global Desertification Assessment by the Millennium Ecosystem Assessment – A Perspective for Better Managing Scientific Knowledge

Cited by 19 publications

References 1 publication

Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis

Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis

Degradation of net primary production in a semiarid rangeland

Spatial Analysis of a Haloxylon Ammodendron Plantation in an Oasis-Desert Ecotone in the Hexi Corridor, Northwestern China

Contact Info

Product

Resources

About