Top PDF Grazing effects on soil characteristics and vegetation of grassland in northern China

Grazing effects on soil characteristics and vegetation of grassland in  northern China

Grazing effects on soil characteristics and vegetation of grassland in northern China

Soil physical characteristics have been shown to be the main factors controlling spatial patterns of soil water and soil nutrients (Zhao et al., 2011). Soil compaction follow- ing heavy grazing can lead to a homogeneous spatial dis- tribution of soil characteristics and increase the vulnerabil- ity of soil water and soil loss, and consequently reduce wa- ter availability for plants and rangeland production (Zhao et al., 2011). With increasing grazing intensity, heterogeneity of soil and plant characteristics changed from a patchy to a homogeneous distribution (Zhao et al., 2011). This was also confirmed in our study where heavy grazing decreased vari- ation in soil properties (SWC, SOC, TN) at the 10 m scale, strongly modified soil property patterns and changed species composition. In our study, 4 years after grazing intensity was changed from heavy grazing to moderate grazing at the MG site, spatial variability of soil properties increased at the MG site compared to the HG site. Livestock grazing resulted in changes to litter input, which may have influenced SOC (Zhao et al., 2005; Su et al., 2006; Lin et al., 2010; Komac et al., 2014). Although Lin et al. (2010) thought those factors resulted in a more homogeneous grazing distribution, they were not strong enough to alter the pre-existing spatial pat- terns of vegetation and soil fertility in their desert steppe. They found that neither SOC nor total N responded to graz- ing intensity at a coarse scale (1–18 m), while soil water con- tent and SOC decreased with increasing grazing intensity at a fine scale (< 2 m) (Lin et al., 2010). Our findings from the typical steppe confirmed that livestock grazing can change the spatial patterns of soil properties at a 10 m 2 scale and make them more homogeneous. The heterogeneity of SOC patches decreased with increasing grazing pressure, which was in agreement with the long-term (> 25 years) responses of SOC spatial patterns to grazing in a semi-arid steppe in Inner Mongolia (Wiesmeier et al., 2009). This was also con- firmed by the findings of Augustine and Frank (2001) who found that semivariance was positively correlated with dis- tance between sampling points in grazed grassland at Yellow- stone National Park, indicating that homogeneous patches occurred at a scale > 30 m for soil N.
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Effects of Simulated Nitrogen Deposition and Precipitation Manipulation on Soil Microorganisms in the Desert Steppe of Northern China

Effects of Simulated Nitrogen Deposition and Precipitation Manipulation on Soil Microorganisms in the Desert Steppe of Northern China

Moreover, Griffiths et al. (2011) provided large-scale confirmation of the role of pH in structuring bacterial taxa. Yuan et al. (2016) also showed that alterations in soil pH and plant composition indirectly affect bacterial community composition. Ramirez et al. (2010) suggested responses in microbial respiration to N addition resulted from direct effects of N availability. A recent study found the change in bacterial structure was caused by nitrogen addition (Zhang and Han, 2012). Our results were inconsistent with the results of the above study. Our data supported that the assemblage of the microbial community driven by arid climates may adapt to desiccation stress and become less sensitive to precipitation changes (Sun et al., 2014; Yao et al., 2017) and low N addition (Sun et al., 2014) in such arid steppe conditions. Due to high evaporation and transpiration with little precipitation, N availability was limited, and N addition plus precipitation manipulation did not result in significant variation in the cultivable bacterial community structure.
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Effects of habitat and landscape characteristics on medium and large mammal species richness and composition in northern Uruguay

Effects of habitat and landscape characteristics on medium and large mammal species richness and composition in northern Uruguay

these species are listed as extinct in the country (the jaguar Pantera onca Linnaeus, 1758; and the puma Puma concolor Linnaeus, 1771). Other species have only been observed a few times in other locations in Rivera (the southern tamandua Tamandua tetradactyla Linnaeus, 1758; and the greater naked- tailed armadillo Cabassous tatouay Desmarest, 1804) and oth- ers are more common, e.g. the brown-nosed coati Nasua nasua Linnaeus, 1766 (Jessica Castro-Prieto pers. comm.). Species such as the lutrine opossum Lutreolina crassicaudata Desmarest, 1804 and the coypu Myocastor coypus Molina, 1782 were not recorded because their typical habitats (e.g. wetlands, and lagoons) were not surveyed. Probably due to its arboreal habits, the Para- guayan hairy dwarf porcupine Sphiggurus spinosus F. Cuvier, 1823 was not recorded. However, one individual was previously observed in one of the study sites. One track of the ocelot Leopardus pardalis Linnaeus, 1758 was found at one of the for- est sites (F1) during a rapid survey in 2006, but the species was not recorded in the present study, probably due to its low abun- dance in the region. The only widely distributed and common species in the country which was not recorded in our study was the southern long-nosed armadillo Dasypus hybridus Desmarest, 1804, a grassland specialist armadillo.
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Growing season methane emission from a boreal peatland in the continuous permafrost zone of Northeast China: effects of active layer depth and vegetation

Growing season methane emission from a boreal peatland in the continuous permafrost zone of Northeast China: effects of active layer depth and vegetation

Gas fluxes were measured by the closed chamber and gas chromatography techniques (Wang and Wang, 2003; Song et al., 2009). The closed chamber was made by stainless steel and consisted of two parts: a square base collar (length: 50 cm, width: 50 cm and height: 20 cm) and a top chamber (length: 50 cm, width: 50 cm and height: 50 or 70 cm) opened at the bottom. The collar was inserted directly into the peat layer to a depth of 15 cm, and kept in the soil during the entire observation period. The top chamber was put on the collar during gas sampling, and immediately removed after gas samples were collected. Two fans were fixed on the in- side symmetrical corners of each chamber to keep the air mixed in the chamber closure during sampling. The cham- bers were wrapped with Styrofoam to prevent an increase in headspace air temperature due to heating when sampling. We built boardwalks to minimize disturbance on the plant and soil microenvironments around collars after the collars were installed.
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Effects of straw incorporation on soil organic matter and soil water-stable aggregates content in semiarid regions of Northwest China.

Effects of straw incorporation on soil organic matter and soil water-stable aggregates content in semiarid regions of Northwest China.

Soil aggregate structural stability is widely recognized as a key indicator of soil quality, which is closely related to a number of soil properties, processes, and functions, e.g., the quantity and composition of SOM [48], infiltration capacity [53], soil biotic activity [54] and the resistance to erosion [55,56]. Wei et al. [57] showed that the addition of crop residues was the most effective measure for increasing the rhizosphere aggregate stability. Sonnleitner et al. [24] and Karami et al. [41] also found that straw application improved the aggregate stability and other soil properties. In our study, the soil aggregate stability of the straw incorporation treatments were significantly higher than CK in 2010, and it was decreased with the soil layer depth. These results agreed with studies by Tripathy and Singh [42] and Karami et al. [41]. Our results also indicated that straw incorporation was positively related to the physical protection of organic matter [20] and an increased aggregate quantity [58], but it also improved the soil aggregate stability [20] and reduced soil degeneration [22,23]. Many studies have shown that soil is a porous medium with fractal characteristics [59–60]. Thus, fractal theory can be used to describe the complex characteristic of soil structure [61]. Castrignano` and Stelluti [62] reported that a higher fractal dimension indicated the heavier texture of a soil and its inferior permeation properties. This showed that fractal theory is an effective method to describing the soil aggregate distribution [37] and changed with different levels of straw incorporation [31]. The fractal dimensions of the 0–40 cm layers with the four treatments
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Clodoaldo Leites Pinheiro2 Fernando Luiz Ferreira de Quadros

Clodoaldo Leites Pinheiro2 Fernando Luiz Ferreira de Quadros

ABSTRACT: Remnant areas of Pampas grassland have a distinct double structure. Efficiency of livestock farming on these grasslands depends on practices that are synchronized with natural variation. This study examined the changes in vegetation composition and forage mass during winter to understand the effects of grazing methods in a natural pasture with a double structure that was grazed by heifers. An experimental area in the municipality of Bagé, Rio Grande do Sul, was subjected to continuous or rotational grazing treatments, with two replicates each. Frequency of the structural composition and forage mass of the lower stratum and animal weight was measured at the beginning and end of the experimental period (June 7 to October 7, 2016, respectively). Data were analysed with PCA ordination, regression and variance analysis. Both structural composition and forage mass changed during the experimental period. Axonopus affinis and Paspalum notatum were characteristic of continuous grazing, while Mnesithea selloana and Axonopus argentinus characterized rotational grazing (the latter had the highest levels of forage mass). Although, grazing methods changed the composition of forage mass in winter, they did not affect average daily gain of the animals.
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Effects of water and nitrogen addition on species turnover in temperate grasslands in northern China.

Effects of water and nitrogen addition on species turnover in temperate grasslands in northern China.

types between our experiment and the other three studies. N addition had no effects on species richness in the present study, which was inconsistent with majority of previous studies but in line with the findings gained from four artificial communities in the UK [37]. The absence of statistical significance of N addition on species richness (Table 1; Fig. 1) may be partly resulted from the relatively short study period of 5 years. Species richness was stimulated by N addition during the first two years, and then decreased for the following years (data not shown). The effect of N addition on species richness was not significant when analyzing the pooled data across the 5-year treatment period (Table 1). These observations suggest that the response of species richness to N addition in semi-arid grasslands may require relatively long-term studies, but the effects of water addition on species richness occurred much more rapidly. Alternatively, the effects of N on species richness are also likely dependent upon soil water conditions and species composition. The lower species richness in the old field than in the steppe is probably because the more competitive exclusion of A. cristatum to other species and the shortage of diverse propagules in the old field.
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Managing Semi-Arid Rangelands for Carbon Storage: Grazing and Woody Encroachment Effects on Soil Carbon and Nitrogen.

Managing Semi-Arid Rangelands for Carbon Storage: Grazing and Woody Encroachment Effects on Soil Carbon and Nitrogen.

infiltration rates into the soil [54, 58]. In our study, soil bulk density was lower in the enclo- sures compared to the open grazing land and the difference was particularly high at low encroachment levels, which may be linked to the fine, sandy clay textured soils of this site. The effect of grazing intensity on bulk density is especially pronounced in wet and fine textured soils[14] as it is susceptible to soil compaction caused by trampling through livestock[14, 58]. Soil compaction potentially reduces water infiltration and increase runoff which often results in decreasing water availability for plant growth [14]. In addition this can lead to loss of top soil and nutrients especially under intense grazing conditions [14, 54]. As a result this can reduce plant productivity and SOC and TSN storage as observed in most of our open grazing lands. Increased soil erosion due to a decrease in vegetation cover associated with continuous, heavy grazing was reported as the main causes for the loss of soil OM in many parts of African and Central Asian grasslands [7, 14, 55].The lack of significant differences in SOC and TSN between the grazing regimes at severely encroached sites (e.g., SE and HE sites) may be the result of both labile and minerals associated OM loss in the top soil due to livestock trampling induced soil erosion, which amplify the negative effects of heavy grazing on herbaceous pro- ductivity and C inputs [59]. Our findings suggest that intensified grazing decreases SOC and TSN stocks, and the losses from the top soil layer can not effectively be restored by short period (< 15 years) grazing exclusion at severely woody encroached sites, particularly on coarse, sandy loam textured soils,which are less resistant to rainfall(e.g., at SE and HE sites).
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The effects of warming and nitrogen addition on soil nitrogen cycling in a temperate grassland, northeastern China.

The effects of warming and nitrogen addition on soil nitrogen cycling in a temperate grassland, northeastern China.

The combined warming and N addition caused an antagonistic effect. This antagonistic effect could be largely explained by the relative changes of soil microbial community structure (B: F) and aboveground plant N content in the combined warming and N addition treatment. The relative lower B: F (Fig. 2B) due to the increase of fungal biomass (Fig. 2D) under combined factors than the single factors may reduce the decomposition process. Firstly, fungal hyphae have long been recognized to enmesh microaggre- gates (,250 m m) into macroaggregates (.250 m m) [28,29], which contributes to SOM stabilization and protection by enhancing soil aggregation. Secondly, fungal cell walls contain more polymers such as melanin and chitin, which can persist in soil for years and account for significant pool of SOM compared with bacteria [30]. In addition, the strongly positive response of aboveground plant N content to combined warming and N addition (Fig. 2G) may also lead to more N uptake by local plants and the rapid decline of soil AN content, which could suppress the positive N effects on soil N mineralization. Similar to warming or N addition, combined warming and N addition only slightly increased soil AN concentration after the three growing season which might have been caused by absorption by local plants and microbes (Fig. 2F, G, H). Thus, these findings suggest that the multifactor effects can differ from simple combinations of single-factor responses. Considering the unprecedented climate warming associated with increasing N deposition under global climate change, multifactor experiments are needed in the future to fully understand the impacts of climatic and atmospheric changes on ecosystem N cycling.
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Field data on vegetation structure and effects of human use of the Dambos ecosystem in northern Mozambique

Field data on vegetation structure and effects of human use of the Dambos ecosystem in northern Mozambique

The six dambos sampled in this study were selected using Google Earth and MODIS satellite images. After the identi fication of the dambos, an exploratory field trip was made to verify whether the candidate dambos were appropriate for the establishment of the survey plots. The selection was required to offer a representative sample size and proximity to the Mbatamila Center Of fice of the Reserve, due to budget constraints and poor road access. A preliminary, basic characterization was conducted in each dambo, which consisted of assessing the occurrence of fire in the last two years, shifting cultivation (Sc), artisanal fishing (Af), soils and vegetation characteristics, seasonal water (Sw)
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Variation in the stable carbon and nitrogen isotope composition of plants and soil along a precipitation gradient in northern China.

Variation in the stable carbon and nitrogen isotope composition of plants and soil along a precipitation gradient in northern China.

In drought-prone ecosystems, water availability controls eco- system structure and processes by affecting long-term balances between ecosystem inputs and outputs of elements and the cycling of carbon and nutrients within ecosystems [1]. The effects of water availability on nutrient cycling in ecosystems are complex. Studies along natural gradients of water availability are helpful and can address these controls [2]. Plant performance along environmental gradients offers one way to evaluate potential plant responses to climate change [3]. Stable carbon and nitrogen isotopic signatures (d 13 C and d 15 N) of plants and soil can serve as valuable non- radioactive tracers and nondestructive integrators of how plants today and in the past have integrated with and responded to their abiotic and biotic environments [4,5,6].
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Traditional cattle grazing in a mosaic alkali landscape: effects on grassland biodiversity along a moisture gradient.

Traditional cattle grazing in a mosaic alkali landscape: effects on grassland biodiversity along a moisture gradient.

Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional grazing management is a crucial issue in grassland conservation actions worldwide. Traditional grazing with robust cattle breeds in low stocking rates is considered to be especially useful to mimic natural grazing regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle grazing as a conservation action in a mosaic alkali landscape. We asked the following questions: (i) How does cattle grazing affect species composition and diversity of the grasslands? (ii) What are the effects of grazing on short-lived and perennial noxious species? (iii) Are there distinct effects of grazing in dry-, mesophilous- and wet grassland types? Vegetation of fenced and grazed plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands) was sampled from 2006–2009 in East-Hungary. We found higher diversity scores in grazed plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their grazed counterparts in the last year in every studied grassland type. We found an increasing effect of grazing from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle grazing is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable livestock type.
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Effects of changed grazing regimes and habitat fragmentation on Mediterranean grassland birds

Effects of changed grazing regimes and habitat fragmentation on Mediterranean grassland birds

The study was conducted in Southern Portugal, mostly within the Special Protection Area (SPA) of Castro Verde (85,000 ha). Cli- mate is Mediterranean, with hot summers (averaging 24.2 ◦ C in July), mild winters (averaging 9.3 ◦ C in January), and more than 75% of annual rainfall (500–600 mm) concentrated in October–March. The landscape is flat or gently undulating (100–300 m a.s.l.) and is dominated by an open agricultural mosaic of cereal, fallow and ploughed fields, created by rotational dry cereal cultivation. From north to south there is a gradient of intensification-abandonment, associated with spatial variation in soil productivity. The northern part is flatter and soils more productive, and so the proportion of land cultivated each year is high and fallow fields are short-term (<3 years). In the south there is a mosaic of shrubland interspersed with old fallow fields (up to 10 years), as a result of agricultural aban- donment and shrub encroachment. Finally, in the central part of the study area the cultivation of cereals is associated with medium to long rotations (2–5 years), and so grazed fallow fields predom- inantly occupy the arable land. Throughout the region there are holm oak (Quercus rotundifolia) pastoral woodlands of variable tree cover (montados). Forest plantations are increasing due to afforesta- tion of abandoned arable land with umbrella pine (Pinus pinea) and holm and cork oaks (Q. suber). In part of the area there is an agri- environment subsidy scheme, whereby farmers are compensated for maintaining agricultural practices favouring bird conservation. Details of the study area are provided elsewhere (Moreira et al., 2007).
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EFFECTS OF STUMP CHARACTERISTICS AND SOIL FERTILITY ON STUMP RESPROUTING OF Schima superba

EFFECTS OF STUMP CHARACTERISTICS AND SOIL FERTILITY ON STUMP RESPROUTING OF Schima superba

Schima superba is a widely distributed and broadly planted broadleaf tree in southern China. Information regarding the probability of stump resprouting, characteristics of the growth of resprouts and their infl uencing factors after disturbance is lacking. In this study, plant survey plots were established in fertile and barren soil conditions one month after a severe ice-snow storm disaster and the resprouting investigations were conducted four years after the treatment. The species showed a rather high (87.8% in total) resprouting probability and independent of stump diameter and soil fertility condition but positively affected by stump height. Stumps in fertile soil can generate more resprouts than in barren soil and there is no infl uence in the subsequent resprouts survival and growth. Stump diameter has no infl uence on the number of resprouts per stump generated, but facilitated the survival and growth of resprouts. Stump height had a positive infl uence on resprouts number per stump generated and a negative infl uence on resprouts growth, but had no signifi cant infl uence on resprouts survival rate and dominant resprouts growth. We recommend conducting a harvest of S. superba at <30 cm aboveground level (traditional method). Fertilization immediately following logging or disturbance and artifi cial resprouts thinning is not recommended for this species.
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Filtration of aluminum alloys and its influence on mechanical properties and shape of eutectical silicium

Filtration of aluminum alloys and its influence on mechanical properties and shape of eutectical silicium

This paradoxical effect can be probably explained by the influence of multiple re-melting. Every re-melt is material exposed to surrounding atmosphere, what results in a formation of more oxide films. The surface oxide films are entrained into the melt, what causes high porosity of test sample and so reduce effective section during a tensile impact test.

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Analysis of the drought resilience of Andosols on southern Ecuadorian Andean páramos

Analysis of the drought resilience of Andosols on southern Ecuadorian Andean páramos

of its soils. Shallow organic soils – classified according to the WRB as Andosols and Histosols – are the two main groups of soils that can be found in this Andean region. These soils are characterized by high levels of organic matter. They have an immense water storage capacity which reduces flood hazards for the downstream areas, while sustaining the low flows all year round for domestic, industrial and environmental uses.

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Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

describe and understanding the evaluated of customer and customer behavior (Tuu & Olsen, 2011:29). Consumer behavior involves risk in the sense that any action of a consumer will produce consequences which he cannot anticipate with anything approximating certainty, and some of which at least are likely to be unpleasant (Bauer, 1960) and sacrifice to obtain a product (Zeithaml, 1988). Value of risk often in empirical study on customer behavior in foods (Knight et al., 2007:794), considering food is basic needs of customer every day. Perceived risk is not only related to consumers’ information acquisition and processing activity but to post- decision processes as well, where people will seek out information that confirms the wisdom of their decision (Horvat & Dosen, 2013:273). Consumer risk perception and its impacts on purchasing behavior are a critical component of the management of food safety (Yeung et al., 2010:306), perceived risk can be explained as consumers’ doubt on the results of their buying decisions (Arslan et al., 2013). It can be interpreted that perception of risk is sacrificed value of customer when buying products as result from selection until interpretation from alternative product. Described of organic product can be measure with financial risk, performance risk, physical risk and social risk (Yee et al., 2011:54). Research on the same years is delivered of measure of risk, especially food include health risk, performance risk, psychosocial risk, and financial risk (Tuu et al., 2011:368). Perception of risk have negative relationship with perception of quality (Kim & Lennon, 2013:33), and on last research found that perception of quality have negative relationship with perception of risk received by customer (Chen & Chang, 2005:521). Based on theoretical study which has been discussed, next determined research hypothesis.
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Beef heifers performance in natural grassland under continuous and rotational grazing in the autumn-winter

Beef heifers performance in natural grassland under continuous and rotational grazing in the autumn-winter

The treatments were two grazing methods: continuous (CONT) and rotational (ROT). In the CONT were used two areas with 4.9ha each and in the ROT were used two areas with 5.6ha subdivided each one in eight paddocks of 0.7ha. In the ROT treatment, the rotational criteria between the animals input and output was the time to thermal accumulative of 375 degree-day (DD). The DD was calculated through the sum of average daily temperatures. Thus, the number of days in each paddock was determined by average daily temperature necessary to reach a similar value to the division of 375 by number of paddocks less one. The rotation established was used to favor the native grass of the functional groups A and B (QUADROS et al., 2009). Furthermore, in the ROT it was selected a representative paddock (in each repetition) from the vegetation characteristics wherein were performed the evaluations of pasture.
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Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Rebonding of sand mix is a common practice in foundry engineering. The sand mix contains used sand whose grains are already coated with the rebonding material. Rebonding of the used sand [3,4] involves disintegration of grain agglomerates and uniform distribution of the rebodning agent in the entire volume of the sand mix batch, coating of sand grains with the rebonding agent and activation of thus formed coating. Turbine (rotor) mixers are now in widespread use as they feature high efficiency and short mixing cycles.
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Assessing land use by cattle in heterogeneous environments

Assessing land use by cattle in heterogeneous environments

The aim of this note is to describe preliminary results on assessment of land use by cattle, obtained in a pilot study using Geographic Information System (GIS). The research was carried out on a semi-natural pasture in Sweden, where the geographic positions of one cow were recorded during 25 consecutive days during summer. The cow, wearing a GPS collar, was integrated in a herd of 53 Hereford cattle. Each location point registered for the animal was considered as a sampling unit (N=3,097). The spatial distribution of ground declivity, water sources, cattle tracks, and classes of woody vegetation cover (forest, grassland with trees and open grassland) were recorded. The storage, processing and data analysis were carried out using the Idrisi and GS+ softwares. Three occupation zones were identified in function of the variation in the space used by the animal, which were occupied in a cyclical pattern; with the animal moving from one zone to another in cycles of five days. It was also clear that the cattle distribution in the area was neither random nor uniform, and it was affected by environmental characteristics that act as conditioners on its distribution. These preliminary results suggest that definition of zones of occupation and the environmental conditioners are promising tools to understand the land use by cattle.
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