Percentage Of Vegetation Cover Research Articles

Reproductive Modes in Leiothrix (Eriocaulaceae) in South-eastern Brazil: The Role of Microenvironmental Heterogeneity

The genus Leiothrix (Eriocaulaceae) is restricted to South America and contains 37 taxa. The genus is most species-rich in the mountains of Minas Gerais, where 25 species occur, 19 of them in the Serra do Cipó. Leiothrix taxa that inhabit different microhabitats exhibit a number of reproductive modes. Rhizomatous taxa produce seeds plentifully; therefore, this group were defined as rhizomatous seed-producing. The pseudoviviparous reproductive mode was divided into canopy-forming and rooted. In the first, ramets remain attached to a parental rosette suspended by scapes, whereas in the second, ramets take root and may or may not remain attached to a parental rosette. In this study, it is proposed that microenvironmental heterogeneity is an important factor generating and maintaining reproductive modes in Leiothrix. Soil analyses and vegetation cover estimates were performed for five Leiothrix taxa occurring in 19 areas along the Serra do Cipó. In these 19 points of the Serra do Cipó, soil data were collected from 27 populations of each species, and vegetation cover data were collected from 20 populations, due to fire that occurred in the region and destroyed most of the vegetation. For each population, three replicates were made. A discriminant function analysis was performed, in an attempt to test the effect of microhabitat features in the differentiation of the reproductive modes. Discriminant function analyses separated the three groups of reproductive modes based mainly on percentage vegetation cover. The pseudoviviparous canopy-forming group occurs under densely crowded conditions, while the pseudoviviparous rooted and rhizomatous seed-producing groups occur in areas with sparse vegetation cover. However, the group pseudoviviparous rooted occurs in soils constituted of exposed sand, while the rhizomatous seed-producing group occurs, frequently, on mat-forming mosses. Microenvironmental heterogeneity, specifically heterogeneity in percentage cover of vegetation, appears to have influenced the generation and maintenance of reproductive modes in Leiothrix. Reproductive variation within Leiothrix taxa occupying different microenvironments results from a response to fine-scale habitat variation. Therefore, it is proposed that ecological speciation is an important process in adaptive radiation in this genus.

Rabbit populations and game management: the situation after 15 years of rabbit haemorrhagic disease in central-southern Spain

Over recent decades wild rabbit populations have undergone a sharp decline in Spain with consequent negative impact both on a game-based economy, and on the conservation of threatened species that depend on rabbits. We investigated the relationships between rabbit population change and habitat and game management in central-southern Spain. To determine recent rabbit population changes we revisited 60 localities during summer 2002 to repeat surveys previously carried out in 1993. Each survey consisted of 4-km walked transects to record indices of rabbit abundance. The percentage of vegetation cover and of different soil types were also estimated during these transects. In the same areas, the type and intensity of game management practices were obtained by interviewing hunting managers, hunters or gamekeepers. Rabbit populations were stable or increasing only in 26.6% of the studied populations, more commonly in areas with soft soils where warren building is easier for rabbits and where rabbits were an important game species and managed to increase their numbers. Although we could not establish causality, habitat management and predator removal were the main management practices related to rabbit population change. Rabbit scarcity in Spain constitutes a serious problem for conservation, so hunters, researchers and policy makers need to reach a consensus to establish a long-term program to monitor rabbit population trends and share results obtained, especially when intense manage programs are being carried out to improve rabbit abundance.

Does the endangered Knysna seahorse, Hippocampus capensis, have a preference for aquatic vegetation type, cover or height?

The Knysna seahorse, Hippocampus capensis, is an endangered teleost confined to three South African estuaries. Its abundance within these systems is low and distributions are patchy. Consequently, monitoring population sizes is labour-intensive. The aim of this study was to establish if Knynsa seahorses are associated with specific regions within the estuaries, on which conservation efforts could concentrate. The relationship of Knysna seahorses with aquatic vegetation was analysed in the Knysna Estuary (the largest of the three estuarine systems inhabited by H. capensis) to determine whether this species shows a preference for a particular plant species, vegetation density or vegetation height. Seahorses were associated with five dominant aquatic plants: Zostera capensis, Caulerpa filiformis, Codium extricatum, Halophila ovalis and Ruppia cirrhosa. Together, these comprised 96% of the submerged objects with which seahorses were associated. The relative abundance of plant species changed along the estuary, but seahorses were present throughout the system, except at the estuary mouth, which was characterized by low plant densities and strong currents. No significant difference was found between the proportion of plant species present in a particular region of the estuary and the proportion of plants that seahorses used as holdfasts. However, when Z. capensis and C. filiformis were present at the same sites, adult seahorses preferred C. filiformis as holdfast. Adult seahorse density (individuals/m2) was significantly correlated with percentage vegetation cover and with holdfast length, but juvenile seahorse density was not. Nonetheless, significantly more adult and juvenile seahorses were found at sites characterized by high vegetation cover (>75%) than at sites with lower cover. Our results indicate that although there is some evidence that Knynsa seahorses prefer certain plant species over others, they are likely to be encountered anywhere in the estuary where aquatic plants are present. Conservation efforts in the Knysna Estuary should thus concentrate on such vegetated areas, which comprise approximately 11% of the total submerged surface area.

Does the endangered Knysna seahorse, Hippocampus capensis, have a preference for aquatic vegetation type, cover or height?

The Knysna seahorse, Hippocampus capensis, is an endangered teleost confined to three South African estuaries. Its abundance within these systems is low and distributions are patchy. Consequently, monitoring population sizes is labour-intensive. The aim of this study was to establish if Knynsa seahorses are associated with specific regions within the estuaries, on which conservation efforts could concentrate. The relationship of Knysna seahorses with aquatic vegetation was analysed in the Knysna Estuary (the largest of the three estuarine systems inhabited by H. capensis) to determine whether this species shows a preference for a particular plant species, vegetation density or vegetation height. Seahorses were associated with five dominant aquatic plants: Zostera capensis, Caulerpa filiformis, Codium extricatum, Halophila ovalis and Ruppia cirrhosa. Together, these comprised 96% of the submerged objects with which seahorses were associated. The relative abundance of plant species changed along the estuary, but seahorses were present throughout the system, except at the estuary mouth, which was characterized by low plant densities and strong currents. No significant difference was found between the proportion of plant species present in a particular region of the estuary and the proportion of plants that seahorses used as holdfasts. However, when Z. capensis and C. filiformis were present at the same sites, adult seahorses preferred C. filiformis as holdfast. Adult seahorse density (individuals/m2) was significantly correlated with percentage vegetation cover and with holdfast length, but juvenile seahorse density was not. Nonetheless, significantly more adult and juvenile seahorses were found at sites characterized by high vegetation cover (>75%) than at sites with lower cover. Our results indicate that although there is some evidence that Knynsa seahorses prefer certain plant species over others, they are likely to be encountered anywhere in the estuary where aquatic plants are present. Conservation efforts in the Knysna Estuary should thus concentrate on such vegetated areas, which comprise approximately 11% of the total submerged surface area.

Comparison of Vegetation Indices and Red‐edge Parameters for Estimating Grassland Cover from Canopy Reflectance Data

AbstractThere has been a great deal of interests in the estimation of grassland biophysical parameters such as percentage of vegetation cover (PVC), aboveground biomass, and leaf‐area index with remote sensing data at the canopy scale. In this paper, the percentage of vegetation cover was estimated from vegetation indices using Moderate Resolution Imaging Spectroradiometer (MODIS) data and red‐edge parameters through the first derivative spectrum from in situ hypserspectral reflectance data. Hyperspectral reflectance measurements were made on grasslands in Inner Mongolia, China, using an Analytical Spectral Devices spectroradiometer. Vegetation indices such as the difference, simple ratio, normalized difference, renormalized difference, soil‐adjusted and modified soil‐adjusted vegetation indices (DVI, RVI, NDVI, RDVI, SAVIL = 0.5 and MSAVI2) were calculated from the hyperspectral reflectance of various vegetation covers. The percentage of vegetation cover was estimated using an unsupervised spectral‐contextual classifier automatically. Relationships between percentage of vegetation cover and various vegetation indices and red‐edge parameters were compared using a linear and second‐order polynomial regression. Our analysis indicated that MSAVI2 and RVI yielded more accurate estimations for a wide range of vegetation cover than other vegetation indices and red‐edge parameters for the linear and second‐order polynomial regression, respectively.

Influence of landscape morphology and vegetation cover on the sampling of mixed plutonic bodies

A plethora of evidence indicates that magma mixing processes can take place at any evolutionary stage of magmatic systems and that they are extremely common in both plutonic and volcanic environments. Furthermore, recent studies have shown that the magma mixing process is governed by chaotic dynamics whose evolution in space and time generates complex compositional patterns. The fact that magma mixing processes can produce igneous bodies exhibiting a large compositional complexity brings up the key question about the potential pitfalls that may be associated with the sampling of these systems for petrological studies. In particular, since commonly only exiguous portions of the whole magmatic system are available as outcrops for sampling, it is important to address the point whether the sampling may be considered representative of the complexity of the magmatic system. Here, we attempt to address this crucial point by performing numerical simulations of magma mixing processes in 3D, and by evaluating the best conditions for sampling by considering different landscape morphologies and percentages of vegetation cover. It is shown that the goodness of sampling is strongly dependant on the roughness of the landscape, with highly irregular morphologies being the best candidates to give the most complete information on the whole magma body. Vegetation cover, on the contrary, does not appear to significantly influence the representativeness of sampling.

Composition, Diversity, and Spatial Relationships of Anurans Following Wetland Restoration in a Managed Tropical Forest

We investigated the composition, diversity, and patterns of spatial use of an anuran community following a wetland restoration project in a managed tropical monsoon forest in southern Taiwan. Anurans comprising eight species in seven genera and four families reached a mean density of 0.025+/-0.004 anurans m(-2) within a year. The three most important species in terms of frequency of occurrence and relative abundance all had an early appearance; only the most abundant Fejervarya limnocharis (62.2% of total accounts), however, remained present throughout the entire year. The distribution of anurans observed among habitat zones was non-random, with most records occurring in densely planted (42.8%) and running-water (23.9%) zones, and the fewest in a buffer zone adjacent to a paved road. Mean numbers of anurans were correlated with the mean percent vegetation cover among individually divided small pools. Microhyla ornate, M. heymonsi, Polypedates megacephalus, and F. limnocharis appeared to be more heterogeneous in their use of space than Buergeria japonicus. Species differed in their most frequently used habitat zones within the wetland site, with the pairs F. limnocharis and P. megacephalus, and M. ornate and Bufo melanostictus, exhibiting similar respective distributions among zones. Our study demonstrates the value of even a small, isolated wetland in contributing to and maintaining regional amphibian diversity. Patterns of spatial relationships of this anuran community have important implications for the conservation of local populations across species.

Response of a desert lizard community to habitat degradation: Do ideas about habitat specialists/generalists hold?

We report the impact of human-induced desertification on the species richness, abundance, and composition of sand dune flora and herpetofauna of North Sinai, Egypt. Our hypothesis was that degraded habitats would have reduced vegetation complexity, richness, and abundance, and consequently lower reptile species richness and abundance. We also hypothesized that desert lizards would not follow the typical generalist/specialist responses to habitat degradation found in other biomes. Instead, we predicted that because vegetation loss intensifies the environmental extremity of deserts, those species specialized for open and sandy environments would be more likely to persist in desertified habitats than would desert generalists. Our results showed that areas protected from vegetation loss did not have significantly higher vegetation richness or abundance except for only a few species. However, protected sites did have significantly higher percent vegetation cover and height. Habitat protection clearly had strong effects on the reptile community as species richness and abundances were significantly higher in protected sites. The composition of the reptile community between protected and unprotected sites differed significantly. Contrary to past studies in other environments, desert generalist species were not able to persist in degraded sites and were only found in protected sites. Specialist species were ubiquitous in that they occurred in both areas protected and unprotected from vegetation loss. We propose that the effects of disturbance on species composition (specialists or generalists) depends on whether the disturbance exacerbates or reduces environmental harshness and the conditions that favor specialization. In extreme environments, specialist and generalist responses to habitat degradation are opposite to that of more productive environments.

Salvage Logging, Edge Effects, and Carabid Beetles: Connections to Conservation and Sustainable Forest Management

We used pitfall traps to study the effects of fire and salvage logging on distribution of carabid beetles over a forest disturbance gradient ranging from salvaged (naturally burned and subsequently harvested) to unsalvaged (naturally burned and left standing). Significantly more carabids were caught in the salvaged forest and the overall catch decreased steadily through the edge and into the unsalvaged forest. We also noted a strong negative correlation between carabid abundance and percent vegetation cover. Beetle diversity as measured through rarefaction was significantly greater at the edge relative to both the unsalvaged and salvaged forest. This stand level study suggests that the amount of edge habitat created by salvage logging has significant implications for recovery of epigaeic beetle assemblages in burned forests by inflating the abundance of “open habitat” species in the initial communities. Carabid beetle responses to salvage logging can differ from responses to harvesting in unburned boreal forest suggesting that management of postfire forests requires special consideration.

Phytoplankton and Zooplankton Associations in a Set of Alpine High Altitude Lakes: Geographic Distribution and Ecology

Species composition and interactions, biomass dominance, geographic distribution and driving variables were investigated for two key elements of the pelagic food web of Alpine lakes, the phytoplankton and the zooplankton, based on a single sampling campaign during summer 2000. Altogether, 70 lakes were surveyed, 49 of which located in three different lake districts of the west and eastern Italian Alps and 21 in the central Austrian Alps (within the uppermost Danube catchment). In addition to the analysis of environmental variables affecting distribution and species structure of the two planktonic compartments, a brief review of the main research lines and hypotheses adopted in the past for the study of phytoplankton and zooplankton in high Alpine lakes is given. The lakes, investigated partly within the European project EMERGE (EVK1-CT-1999-00032) and partly within a regional project in the eastern Alps, comprise a wide range of morphological, chemical and trophic conditions. The phytoplankton communities were found to be diverse and mostly dominated by flagellates (chrysophytes, cryptophytes and dinoflagellates), and only to a lesser extent by non-motile green algae, desmids and centric diatoms. The zooplankton communities were mainly dominated by Alpine cladocerans and copepod species, while rotifers were abundant within one group of Italian lakes (sampled in early summer). The multivariate statistical analyses (CCA) showed that catchment features (i.e. percentage of vegetation cover and geochemical composition) and nitrate concentration are essential drivers for the phytoplankton, whereas for zooplankton also trophic status of the lakes and phytoplankton structure are important. The combined variance analysis of the lake clusters outlined by the multivariate analyses on phytoplankton and zooplankton data, respectively, allowed the identification of four principal lake types (three located on siliceous and one on carbonaceous bedrock), each one characterised by a certain combination of habitat features, which in their turn influence trophic state, and phytoplankton and zooplankton species composition and functionality.

DIFFERENT SPATIAL DISTRIBUTION OF AEDES AEGYPTI AND AEDES ALBOPICTUS ALONG AN URBAN–RURAL GRADIENT AND THE RELATING ENVIRONMENTAL FACTORS EXAMINED IN THREE VILLAGES IN NORTHERN THAILAND

A larval survey of dengue vectors was conducted from July to November 1966 and from May to November 1997 in Chiangmai Province, Thailand. Three villages in urban, transition, and rural areas were selected for the survey to clarify the spatial distribution of Ae. aegypti and Ae. albopictus along an urban-rural ecological gradient. The average number of Ae. aegypti larvae in larvitraps was higher in the urban area than in the rural area, as we expected, whereas the opposite was found for Ae. albopictus, rural area > urban area. A house survey of larvae-inhabiting containers showed significant differences in the number and composition of these containers among the study areas. Significant differences were also found in the average distance between houses, average tree height, and average percentage of vegetation cover for each house. The seasonal pattern of rainfall recorded in each study area did not show great differences among the study areas. The response of Ae. aegypti and Ae. albopictus to the urban-rural gradient is discussed in relation to the possibility of applying geographic information system techniques to plan the control strategy and surveillance of dengue vectors.

Studying the Relationship Between Vegetation and Physico-Chemical Properties of Soil, Case Study: Tabas Region, Iran

In order to study the relationship between vegetation and physico-chemical properties of soil of the margins of Tabas Kavir (salty desert), vegetation and soil components were surveyed. Regarding to the soil and vegetation distribution and land use in this region, four distinct areas were selected and classified covering all factors. Then, based on different vegetation cover percentage, the minimum plots necessary for validating statistical calculations were assessed. In this case, the plots equal to two fold of assessed value for maximum vegetation cover percentage, i.e 310 spots, were randomly and systematically selected and sampled. According to the observations and based on soil properties in each sampling spots, statistical calculations were done using linear regression to determine the relationship between the distribution of species and soil properties including CaSO , CaCO , gravel percentage, pH and EC. The best equation was 4 3 then selected among the 11 suggested equations. This case studied also focused on the some soil factors as variables and their effects on the growth of some plant species (Seidlitzia rosmarinus, Haloxylon aphylum, Alhagi camelorum, Tamarix sp, Prosopis srephaniana, Artemisia siberi, Salsola spp). Generally, in other similar areas like Tabas, these plant species are recommended which show resistant behaviors to such harsh conditions. More efforts should be done to realize other aspects of relationship between soil factors and plants, especially in dry lands.

On urban heat island of Beijing based on landsat TM data

Land surface temperature (LST) of Beijing area was retrieved from Landsat TM thermal band data utilizing a radiative transfer equation and the urban heat island (HUI) effects of Beijing and its relationship with land cover and normalized difference vegetation index (NDVI) were discussed. The result of LST showed that the urban LST was evidently higher than the suburban one. The average urban LST was found to 4. 5°C and 9°C higher than the suburban and outer suburban temperature, respectively, which demonstrated the prominent UHI effects in Beijing. Prominent negative correlation between LST and NDVI was found in the urban area, which suggested the low percent vegetation cover in the urban area was the main cause of the urban heat island.

Assessing factors related to wolf depredation of cattle in fenced pastures in Montana and Idaho

Managing wolf (Canis lupus) depredation on livestock is expensive and controversial; therefore, managers seek to improve and develop new methods to mitigate conflicts. Determining which factors put ranches at higher risk to wolf depredation may provide ideas for ways to reduce livestock and wolf losses. We sampled cattle pastures in Montana and Idaho that experienced confirmed wolf depredations (n = 34) from 1994–2002 and compared landscape and selected animal husbandry factors with cattle pastures on nearby ranches where depredations did not occur (n = 62). Pastures where depredations occurred were more likely to have elk (Cervus elaphus) present, were larger in size, had more cattle, and grazed cattle farther from residences than pastures without depredations. Using classification tree analysis, we found that a higher percentage of vegetation cover also was associated with depredated pastures in combination with the variables above. We found no relationship between depredations and carcass disposal methods, calving locations, calving times, breed of cattle, or the distance cattle were grazed from the forest edge. Most pastures where depredations occurred during the wolf denning season (April 15-June 15) were located closer to wolf dens than nearby cattle pastures without depredations. Physical vulnerability, especially of calves, also may increase risk of depredation.

Vegetation responses along environmental gradients on the Ordos plateau, China

AbstractThe Ordos plateau is a unique ecotone and is a focal region for the campaign to reduce or reverse desertification in China. This paper explores the relationship between vegetation and environmental gradients on the Ordos plateau based on a field survey of species distribution, vegetation distribution patterns, plant community structure, ecophysiological properties, and soil water content along an environmental gradient. The vegetation on the Ordos plateau may be divided into three types from east to west: steppe (eastern part), desert steppe (middle part) and steppe desert (western part). From east to west, precipitation declines significantly (from 400 mm to 150 mm). The spatial distribution pattern of vegetation at different sites was random. The density of shrub islands decreased from east to west, and their height and diameter were negatively correlated with precipitation. From east to west, the transpiration rate increased as temperature increased. Stomatal conductance was positively correlated with percentage of sunshine hours and negatively correlated with temperature. Water‐use efficiency was positively correlated with average annual precipitation but negatively correlated with increasing percentage of sunshine hours. The results suggest that for effective revegetation, highly drought‐tolerant species, such as Caragana tibetica and C. stenophylla, should be used and a lower percentage of vegetation cover expected (30–40%) in the western half of the Ordos plateau. In the eastern half, moderately drought‐tolerant species, such as Artemisia ordosica and C. korshinskii, could be used and a higher percentage vegetation cover expected (40–50%).

Habitat preferences of lesser rheas in Argentine Patagonia

This work reports the first results of a 3-year study (1998–2001) on habitat use and preferences by wild lesser rheas (Rhea pennata pennata) in the ecotone Monte–Patagonian steppe of Argentina. Ponds and four different habitat alternatives for lesser rheas were determined using satellite images and different structural vegetation characteristics: steppe, shrubland, shrub steppe, and mallines. Lesser rheas (adults, juveniles and chicks) used all habitats available to feed, although they showed preference for mallines, open areas that offer good visibility and abundant food resource. Rheas used shrub steppe and steppe for nesting, but they did not show preference for either habitat type. Nest site had a higher percentage of vegetation cover than control sites. Lesser rheas apparently preferred concealed sites for nesting since they offer protection from severe climate conditions and from predators. Our results suggest that habitat preference by lesser rheas counterbalances profitability of feeding to the corresponding cost of predation.

Soil amendments reduce trace element solubility in a contaminated soil and allow regrowth of natural vegetation

We tested the effects of three amendments (a biosolid compost, a sugar beet lime, and a combination of leonardite plus sugar beet lime) on trace element stabilisation and spontaneous revegetation of a trace element contaminated soil. Soil properties were analysed before and after amendment application. Spontaneous vegetation growing on the experimental plot was studied by three surveys in terms of number of taxa colonising, percentage vegetation cover and plant biomass. Macronutrients and trace element concentrations of the five most frequent species were analysed. The results showed a positive effect of the amendments both on soil chemical properties and vegetation. All amendments increased soil pH and TOC content and reduced CaCl 2-soluble-trace element concentrations. Colonisation by wild plants was enhanced in all amended treatments. The nutritional status of the five species studied was improved in some cases, while a general reduction in trace element concentrations of the aboveground parts was observed in all treated plots. The results obtained show that natural assisted remediation has potential for success on a field scale reducing trace element entry in the food chain.

Establishment and Growth of Experimental Grass Species Mixtures on Coal Mine Sites Reclaimed with Municipal Biosolids

The Surface Mining Control and Reclamation Act of 1977 requires that coal mine sites in the United States be reclaimed to establish vegetative cover that is diverse, native, and capable of plant succession. However, there is a question as to whether vegetation established on coal mine sites reclaimed with biosolids is diverse and capable of plant succession. The influx of nutrients with the addition of biosolids leads to long-term dominance by early-successional species, most notably grasses, and consequently, a low establishment of woody and volunteer species. Additionally, many grass species commonly planted in reclamation have aggressive growth habits that lead to their dominance in coal mine plant communities. The establishment and growth of selected grass mixes was evaluated to determine whether alternative grass mixes would be less competitive with woody and volunteer species as compared to commonly used grass mixes. Percent vegetative cover, species richness, and the survival of direct-seeded woody species were assessed for each treatment grass mixture. It was found that Poa compressa and a mixture of P. compressa, Panicum virgatum, and Trifolium repens provided adequate coverage while still allowing the highest species richness and survival of woody species. Use of these species mixtures in coal mine reclamation with biosolids in the eastern United States would likely lead to establishment of a more species-rich plant community with a greater woody species component while still providing erosion control and site protection.

Land and vegetation degradation in war-affected areas in the Sabah Al-Ahmad Nature Reserve of Kuwait: A case study of Umm. Ar. Rimam

Following the liberation of Kuwait from Iraqi aggression, the remaining munitions were disposed by detonating them in large pits in the Umm. Ar. Rimam depression of the Sabah Al-Ahmad Nature Reserve of Kuwait. These pits were then back-filled. After 10 years, the status of the soil and vegetation in the munition disposal pits and adjacent areas were assessed to assist with the design of a pilot study to rehabilitate the impacted area to its pre-invasion state. Based on a reconnaissance survey, a site measuring 120,000 m 2 (12 ha) was selected in Umm. Ar. Rimam depression. On-site observations showed that damage to this site was caused by (i) munition disposal pits (11.3% of the area), (ii) compacted area between pits (36.4%) and, (iii) compacted road tracks (3.6%). The field investigations of soil profiles and laboratory characterization of soil samples indicated serious disruption of pedogenic processes, loss of top soil, severe soil compaction, reduction in infiltration rate, contamination with munition materials and alterations in chemical properties. Based on a rating scale of 0 (no impact) to 4 (very severely impacted), the areas covered under munitions disposal pits and compacted areas between pits and under road tracts are categorized as severely and very severely disturbed sites. Although the pits contained higher vegetation cover than the adjacent compacted areas, the percent vegetation cover was significantly lower than that during the pre-disturbance period. Soil and vegetation assessment also confirmed that the natural recovery did not restore land and vegetation to their pre-disturbance status.

Land degradation indicators in Kuwait

AbstractIn arid regions, such as Kuwait, land degradation is exacerbated by the scarcity of rainfall and intensive wind and water erosion. In Kuwait seven land degradation indicators were recognized and described. These are: soil erosion by wind and/or water; deterioration of vegetation cover; soil crusting and sealing; soil compaction; soil contamination by oil; and soil salinization. Four areas in Kuwait, namely Al Mutlaa, Ras Al‐Sabiyah, Sulaibiyah and Ahmadi‐Al‐Dahr, were studied to assess the extent and magnitude of land degradation. Remote sensing images and the following parameters were investigated in each area: vegetation cover; soil bulk density; infiltration capacity; and top soil resistance. The areas showed significant variations in vegetation cover, and increase in erosion by wind and water and soil compaction. Based on the percentage of vegetation cover and the physical properties of the soil, three classes of land degradation are identified. These classes are: severe; moderate; and slight. Overgrazing was shown as a main cause of land degradation, followed by military operations, quarrying and camping. Copyright © 2005 John Wiley & Sons, Ltd.