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Effects of land cover on chemical characteristics of streams in the Cerrado region of Brazil

Journal Articles & Books
Dezembro, 2011
Brasil

The Cerrado is the second largest Brazilian biome and contains the headwaters of three major hydrological basins in Brazil. In spite of the biological and ecological relevance of this biome, there is little information about how land use changes affect the chemistry of low-order streams in the Cerrado. To evaluate these effects streams that drain areas under natural, rural, and urban land cover were sampled near Brasília, Brazil. Water samples were collected between September 2004 and December 2006. Chemical concentrations generally followed the pattern of Urban > Rural > Natural.

Bacterial pathogens in Hawaiian coastal streams—Associations with fecal indicators, land cover, and water quality

Journal Articles & Books
Dezembro, 2011

This work aimed to understand the distribution of five bacterial pathogens in O’ahu coastal streams and relate their presence to microbial indicator concentrations, land cover of the surrounding watersheds, and physical–chemical measures of stream water quality. Twenty-two streams were sampled four times (in December and March, before sunrise and at high noon) to capture seasonal and time of day variation. Salmonella, Campylobacter, Staphylococcus aureus, Vibrio vulnificus, and V. parahaemolyticus were widespread —12 of 22 O’ahu streams had all five pathogens.

Aphid parasitoids respond to vegetation heterogeneity but not to fragmentation scale: An experimental field study

Journal Articles & Books
Dezembro, 2016

How animal populations respond to habitat manipulations is a central theme in ecology. In recent years, the role that vegetation heterogeneity plays in regulating arthropod populations has received particular attention in both conservation science and agricultural ecology. Numerous observational studies have demonstrated that herbivores and their natural enemies are sensitive to vegetation heterogeneity, but the individual effects of percentage land cover, degree of fragmentation and patch size remain little understood.

Using modeled runoff to study DOC dynamics in stream and river flow: A case study of an urban watershed southeast of Boston, Massachusetts

Journal Articles & Books
Dezembro, 2012

The origin, function, and fate of dissolved organic carbon (DOC) in stream flow are not well-understood. This study explores the environmental factors controlling the spatial and temporal variation of DOC in terrestrial ecosystems of a watershed southeast of Boston, Massachusetts. Our hypothesis is that environmental factors: stream flow, land cover type, vegetation density, and drainage area are significant in estimating DOC export from an urban watershed.

Does landscape composition affect pest abundance and their control by natural enemies? A review

Journal Articles & Books
Dezembro, 2013

Landscape management could contribute to sustainable pest control. Landscape composition, in particular, could either directly impact a pest abundance by affecting its dispersal, mortality or reproduction, or indirectly by affecting its natural enemies. We performed an analysis of the scientific literature to assess how the proportion of different land covers at the landscape level is related to the abundance of pests or to their control by natural enemies. Of 72 independent case studies, 45 reported an effect of landscape composition.

Detecting land use/land cover changes in the Lake Hayq (Ethiopia) drainage basin, 1957–2007

Journal Articles & Books
Dezembro, 2015
Etiópia

Land use/land cover changes in a lake drainage basin reflect changes in the magnitude of the water balance components and rate of sediment deposition in a lake as a reflection of the fundamental linkage between what happens in a lake considered against what is happening in the drainage basin of the lake. The objective of this study was to quantify the spatio‐temporal land cover/land use changes across the Lake Hayq closed drainage basin in north‐east Ethiopia over a 50‐years period, using multitemporal remote sensing and geospatial data.

Flora biodiversity change detection: a case study

Journal Articles & Books
Dezembro, 2013

Changes in flora biodiversity are a dilemma facing managers in order to cope with challenges of extinction or endangering plant species as well as replacement by invasive species. Such problems can occur in the region as disruption of ecosystem balance. The first step of proper management of a watershed is obtaining accurate information about plant communities and their dominance and biodiversity status. Such information will help decision makers to adopt an appropriate management approach.

multifaceted view on the impacts of shrub encroachment

Journal Articles & Books
Dezembro, 2016

Shrub encroachment, a global phenomenon with management implications, is examined in two papers in the current issue of Applied Vegetation Science. Barbosa da Silva et al. show that encroachment simplifies the herbaceous community, and Pittarello et al. illustrate how pastoral practices can restore encroached grasslands. While detrimental effects of shrub encroachment on grassland vegetation are often reported, we argue for a more holistic view when assessing this land‐cover change.

hydrologic consequences of land cover change in central Argentina

Journal Articles & Books
Dezembro, 2012
Argentina
América do Sul

Vegetation exerts a strong control on water balance and key hydrological variables like evapotranspiration, water yield or even the flooded area may result severely affected by vegetation changes. Particularly, transitions between tree- and herbaceous-dominated covers, which are taking place at increasing rates in South America, may have the greatest impact on the water balance.

Deforestación en ecosistemas templados de la precordillera andina del centro-sur de Chile

Journal Articles & Books
Dezembro, 2010
Chile

A multitemporal analysis to determine the land cover change was conduced in the pre-Andean range of Maule region of Chile. We used satellite imagery from the year 1989 and 2003 to analyze the likely causes of native forest change. In this period, there was a reduction in native forest area of 44% in the study area, which is equivalent to an annual forest loss rate of 4.1%. The native forest area is replaced by shrublands (29%) and exotic forest plantations (27%). A great proportion of current exotic forest plantations are established on lands that were native forest in 1989 (63%).

Vegetation change and land tenure in Mexico: A country-wide analysis

Journal Articles & Books
Dezembro, 2013
México

There is an ongoing debate on the effect different property regimes have on the use of natural resources and land conversion (i.e., deforestation or reforestation). Much of the discussion has been centered on the two main forms of tenure regime: common-pool system and private property. Case studies around the world have provided evidence on whether one is more effective at preventing deforestation than the other, but there is not a clear pattern. Part of the problem is that evidence comes from theoretical models or isolated case studies instead of comparative studies across large areas.

Distribution and nesting success of ferruginous hawks and Swainson's hawks on an agricultural landscape in the Great Plains

Journal Articles & Books
Dezembro, 2014
Estados Unidos

We studied nest site land cover associations, and reproductive success of two Buteo species of conservation concern on the southern Great Plains, USA. The study area was in Cimarron County, Oklahoma, where land use is dominated by row crop agriculture, livestock grazing, and Conservation Reserve Program grasslands. Ferruginous Hawks (B. regalis) were uncommon and nested primarily in and around the Rita Blanca National Grassland (NG). Swainson’s Hawks (B. swainsoni) were common and nested throughout the study area.