scholarly journals Aves de pastizal invernando en México: relaciones de densidad y hábitat//Wintering grasslands birds in Mexico: density and habitat relationships

Biotecnia ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 163-170
Author(s):  
Daniel De León-Mata ◽  
José Hugo Martínez-Guerrero ◽  
Martín Pereda-Solís ◽  
Daniel Sierra Franco ◽  
Christian Wehenkel ◽  
...  
Keyword(s):  
Vegetation Cover ◽  
Chihuahuan Desert ◽  
Good Condition ◽  
Bare Soil ◽  
Conservation Strategies ◽  
Focal Species ◽  
Ammodramus Savannarum ◽  
Anthus Spragueii ◽  
Wintering Areas ◽  
Northwestern Mexico

Las poblaciones de aves de Norteamérica, y en particular las de pastizales, están disminuyendo. En un área de pastizales del noroeste de México, entre 2009 y 2011, estimamos la densidad invernal de tres especies de pastizal: Centronyx bairdii (BAIS), Ammodramus savannarum (GRSP) y Anthus spragueii (SPPI) y su relación con los atributos de la vegetación y cobertura de suelo. Los promedios de densidad calculados para BAIS, GRSP y SPPI fueron 50.8, 76.7 y 12.6 (aves/km2) respectivamente, estas densidades son mayores que las estimaciones en la mayoría de las áreas de invernada en el Desierto Chihuahuense. El test de Kruskal-Wallis, demuestra que existen algunas diferencias en el uso de hábitat entre las tres especies. Las estimaciones de la cobertura y altura de la vegetación para cada especie mostraron algunas diferencias entre años (2010, 2011). Los valores de covariación de Gregorius (C), muestran que las especies estudiadas tienen una correlación significativa (P <0.025) con seis variables de atributos de vegetación invernal (altura y cobertura de pasto y hierba, suelo desnudo, y cobertura de arbusto). Los resultados de este estudio permiten reconocer que las tres especies de aves estudiadas requieren áreas de pastizal en buena condición. Por ello, es necesario establecer estrategias de conservación que mitiguen la alteración de los pastizales del Desierto de Chihuahuense.ABSTRACTBird populations in North America and in particular, grassland populations, are declining. We estimated winter density in three grassland focal species: Centronyx bairdii (BAIS), Ammodramus savannarum (GRSP) and Anthusspragueii (SPPI) and its relationship with vegetation cover between 2009 and 2011, in a grassland area of northwestern Mexico. The density averages calculated for BAIS, GRSP and SPPI were 50.8, 76.7 and 12.6 (birds / km2) respectively, are higher than previous estimations in most wintering areas in the Chihuahuan desert. The Kruskal-Wallis test shows that there are some differences in habitat use between the three species. Estimates of vegetation cover and height for each species showed some differences between years (2010 and 2011). Gregorius covariation values (C) indicate that the studied species have a significant correlation (P <0.025), with six variables of winter vegetation attributes (height and grass and grass cover, bare soil, and bush cover). The results found allow us to recognize that these birds require grassland areas in good condition, so it is necessary to establish conservation strategies that might help mitigate the alteration of the grasslands of the Chihuahuan desert.

scholarly journals Environmental effectiveness of GAEC cross-compliance Standard 1.1a (temporary ditches) and 1.2g (permanent grass cover of set-aside) in reducing soil erosion and economic evaluation of the competitiveness gap for farmers

2016 ◽  
Vol 10 (1s) ◽  
Author(s):  
Paolo Bazzoffi ◽  
Rosa Francaviglia ◽  
Ulderico Neri ◽  
Rosario Napoli ◽  
Alessandro Marchetti ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Vegetation Cover ◽  
Bare Soil ◽  
Runoff Water ◽  
Rusle Model ◽  
Environmental Effectiveness ◽  
Additional Costs ◽  
Soil Erosion By Water ◽  
Cross Compliance ◽  
Made In

<p>This paper shows the results of the monitoring carried out in three hilly farms of the MONACO project in order to verify the effectiveness of the Standard 1.1 <sub>(commitment a)</sub> (temporary ditches) and Standard 1.2 <sub>(commitment g)</sub> (Vegetation cover throughout the year in set-aside land) in the reduction in soil erosion, contained in Rule 1: ‘minimum land management that meets specific conditions’ of the decree Mipaaf 2009 and following modifications, until the recent decree No. 180 of January 23, 2015. In addition, the assessment of the competitiveness gap was done. That is the evaluation of the additional costs borne by the beneficiary of the single payment determined from agronomic commitments. Monitoring has also compared the erosion actually observed in the field with that predicted by RUSLE model (Revised Universal Soil Loss Equation) (Renard et al., 1997) in the two situations: with and without the presence of temporary ditches, i.e. assuming Factual (compliance rules) and in that Counterfactual (infringement). This comparison was made in view of the fact that the RUSLE model was chosen by the 'European Evaluation Network for Rural Development (EEN, 2013) as a forecasting tool for the quantification of' Common Indicator ‘soil erosion by water’. The results of soil erosion survey carried out by using a new  UAV-GIS methodology  on two monitoring farms in two years of observations have shown that temporary ditches were effective in decreasing erosion, on average, by 42.5%, from 36. 59 t ha<sup>-1</sup> to 21.05 t ha<sup>-1</sup> during the monitoring period. It was also evaluated the effectiveness of grass strips (at variance with the commitment of temporary ditches). The results showed a strong, highly significant, reduction in erosion by about 35% times respect soil erosion observed in bare soil and also a significant reduction in the volume of runoff water.  With regard to Standard 1.2 <sub>(commitment g)</sub> the statistical analysis shows a strong and highly significant decrease in the erosion due to the vegetation cover of the soil compared to bare soil. The economic competitiveness gap of  Standard 1.1<sub>(commitment a)</sub> stood at € 4.07±1.42 € ha<sup>-1</sup> year<sup>-1</sup>, while CO<sub>2</sub> emissions due to execution of temporary ditches was 2.58 kg ha<sup>-1</sup>year<sup>-1</sup>. As for the Standard 1.2 <sub>(commitment g) </sub>the average differential competitiveness gap amounted to  50.22±13.7 € ha<sup>-1</sup> year<sup>-1</sup> and an output of CO<sub>2</sub> equal to 31.52  kg ha<sup>-1</sup> year.</p>

Dietary selection by goats and the implications for range management in the Chihuahuan Desert: a review

2016 ◽  
Vol 38 (4) ◽  
pp. 331 ◽  
Author(s):  
M. Mellado
Keyword(s):  
Chihuahuan Desert ◽  
Good Condition ◽  
Secondary Compounds ◽  
Field Studies ◽  
Arid Environment ◽  
Larrea Tridentata ◽  
Desert Rangelands ◽  
Lactating Goats ◽  
Varied Diet ◽  
Sources Of Variation

Field studies characterising the forage resources of mixed-breed goats on Chihuahuan Desert rangelands were reviewed and the principal sources of variation in their diet choices discussed. Goats eat a varied diet comprising at least 126 plant species in this landscape. Goats are highly selective feeders, changing their diet from predominantly forbs (8–64%) to browse (35–88%). Graminoids make up only ~5% of the diet, but grasses could be important dietary components on rangelands in good condition. Feed intakes range between 0.8% and 3.4% of bodyweight, depending on the season. DM digestibility of forage selected by goats ranges between 44% and 65%. Annual crude protein (CP) in forages selected by goats varies from 80 to 160 g CP kg–1 DM. Overall, pregnant and lactating goats manage to ingest food that contains higher amounts of CP and lower amounts of cell wall than non-pregnant, non-lactating goats. Goats not adapted to severe shortage of forage select a diet that does not match their nutritional requirements and fetal losses occur. Goat kids select higher quality diets than do mature goats (94.5 vs 88.5 g CP kg–1 DM). Granadina goats eat ~20% more shrubs, including 3-fold more Larrea tridentata (DC) Cav., than Nubian goats. Goats with severely eroded incisors avoid grasses, focusing on tender-leaved shrubs. During the rainy season, bucks select mainly shrubs (78% of the diet) and avoid grasses (1.7% of the diet), whereas does rely heavily on forbs (about one-third of their diet). Alternating use of grazing grounds increases shrub ingestion by 25%. No evidence exists indicating that food choice by goats in this arid environment is biased towards forages with lower secondary compounds. It is concluded that the flexible, broad-scale and opportunistic feeding behaviour of goats make them an effective animal to sustainably exploit the forage resources of the Chihuahuan Desert.

Buried propagule bank of a high subalpine site: microsite variation and comparisons with aboveground vegetation

1993 ◽  
Vol 71 (5) ◽  
pp. 712-717 ◽  
Author(s):  
Cheryl A. Ingersoll ◽  
Mark V. Wilson
Keyword(s):  
Spatial Pattern ◽  
Key Words ◽  
Seed Bank ◽  
Vegetation Cover ◽  
Bare Soil ◽  
Soil Cores ◽  
Cascade Mountains ◽  
Greenhouse Soil ◽  
Propagule Bank ◽  
Bare Soils

We assessed the composition and spatial pattern of the persistent buried propagule bank (seeds and vegetative structures) of a treeline site in the Oregon Cascade Mountains. We monitored emergence from soil cores removed from four microsite types and recorded vegetation cover and seedling abundance on the site. Over 3100 seedlings/m2 emerged from the greenhouse soil cores; the seed bank was dominated by Juncus species. Few vegetative sprouts emerged. Vegetated microsites produced significantly more emergents than did bare soils, but even bare soils contained abundant seeds. Overall site cover was low and few seedlings occurred on the site. Discrepancies between aboveground and belowground abundance were common. Phyllodoce empetriformis and Luetkea pectinata were abundant in the vegetation and produced many seeds but were poorly represented in the seed bank and as seedlings on the site. Other species were abundant in the seed bank, but rare in the vegetation. Our results indicate that despite the abundance of seeds in bare soil, colonization is likely to be extremely slow. Key words: seed bank, subalpine, seedlings, microsite, spatial pattern.

scholarly journals Aplicação do protocolo de avaliação rápida (par) na caracterização da qualidade ambiental de trechos do Rio Piumhi, Minas Gerais - Brasil

ForScience ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. e00968
Author(s):  
Eline dos Santos Oliveira ◽  
Júlia Helena Passos Veloso ◽  
Hygor Aristides Victor Rossoni
Keyword(s):  
Water Resources ◽  
Environmental Quality ◽  
Vegetation Cover ◽  
Good Condition ◽  
Minas Gerais ◽  
Rapid Evaluation ◽  
Evaluation Protocol ◽  
Water And Sediment

Nas últimas décadas, os ecossistemas aquáticos têm sido alterados de maneira significativa. Diante disso, faz-se necessária a conservação dos recursos hídricos. O objetivo deste trabalho é estimar a qualidade ambiental do Rio Piumhi, que já sofreu transposição de suas águas, por meio de protocolo de avaliação rápida das características da água e sedimentos, situação e estado de conservação das margens, matas ciliares, cobertura vegetal e presença de erosão e assoreamento. A aplicação do protocolo gera empoderamento da sociedade quanto à gestão dos recursos hídricos. O protocolo com treze parâmetros foi aplicado em seis locais sujeitos às atividades humanas, na qual foram atribuídas pontuações. Foi possível constatar que três dos seis locais analisados se encontraram em boa, um em ótima e dois em regular condição. A maior parte dos locais apresentou cobertura vegetal nativa degradada, sendo urgente a preservação desse curso hídrico. Palavras-chave: Rio Piumhi. Protocolo de avaliação rápida. Bacia hidrográfica. Application of the rapid evaluation protocol (rep) on the characterization of the environmental quality of the Rio Piumhi sections, Minas Gerais - Brazil Abstract In recent decades, aquatic ecosystems have changed significantly. Therefore, it is necessary to conserve water resources. The objective of this work is to estimate the environmental quality of the Piumhi River, which has already undergone transposition of its waters, by means of a rapid evaluation protocol of water and sediment characteristics, situation and state of conservation of banks, riparian forests, vegetation cover and presence of erosion and siltation. The application of the protocol generates the empowerment of society regarding the management of water resources. The protocol with thirteen parameters was applied in six locations subject to human activities, in which scores were assigned. It was possible to verify that three of the six places analyzed were in good condition, one in excellent condition and two in regular condition. Most of the locations had degraded native vegetation cover, making it imperative to preserve this water course Keywords: Piumhi River. Rapid evaluation protocol. Watershed.

scholarly journals MULTI-TEMPORAL ANALYSIS OF LAND USE AND VEGETATION COVER IN SÃO FRANCISCO DO SUL AND ITAPOÁ, SANTA CATARINA STATE - BRAZIL: IMPLICATIONS TO GROUNDWATER CONTAMINATION

2021 ◽  
Vol XLIII-B3-2021 ◽  
pp. 305-311
Author(s):  
A. C. S. J. V. Ferreira ◽  
L. S. Osako
Keyword(s):  
Land Use ◽  
Groundwater Contamination ◽  
Vegetation Cover ◽  
Groundwater Vulnerability ◽  
Temporal Analysis ◽  
Bare Soil ◽  
Unconsolidated Sediments ◽  
Northern Coast ◽  
Santa Catarina ◽  
Urbanized Area

Abstract. By means of the multitemporal approach, we analyze the changes in land use and vegetation cover in the São Francisco do Sul and Itapoá municipalities, located in the northern coast of the State of Santa Catarina, Brazil. LANDSAT satellite images from 1991 to 2019 were analyzed and classified into four classes of soil use and occupation (vegetated area, bare soil, urbanized area, and water body) by the GEOBIA method. Weighted sum analysis was applied to the ‘urbanized area’ class and the data available on geologic units, so as to identify areas vulnerable to groundwater contamination. The vegetated areas of São Francisco do Sul and Itapoá have diminished along the 2000’s, but recovery measures, such as reforesting and restraint of soil exposure, have been adopted, with 89.61% success. The urban zone has increased 3.36% in the last 28 years. The achieved overall accuracy for the classification was of 79.33% and the Kappa coefficient was 0.69. The analysis of groundwater vulnerability to contamination helped identify regions more susceptible to pollution, which coincide almost entirely with those where urbanization was more intense in areas where unconsolidated sediments predominate.

scholarly journals Molt of the Gray Vireo

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 610-618 ◽  
Author(s):  
Gary Voelker
Keyword(s):  
United States ◽  
Late Summer ◽  
Museum Specimens ◽  
Adult Males ◽  
Wintering Grounds ◽  
Dietary Shift ◽  
Breeding Grounds ◽  
Wintering Areas ◽  
Desert Regions ◽  
Northwestern Mexico

AbstractUsing museum specimens, I document the molt cycles and molting grounds of the Gray Vireo (Vireo vicinior). During prebasic molts, adult female Gray Vireos replace their primaries in 57 days, whereas adult males take 70 days; all body plumage is replaced during this molt. Prebasic molts occur almost exclusively on the breeding grounds; just 3 of 41 specimens replacing primaries were collected away from breeding grounds. No molting specimens were collected from wintering areas. Prealternate molt occurs on the wintering grounds, and appears limited to the replacement of innermost secondaries and a limited molt of body plumage. By performing prebasic molt on breeding grounds, the Gray Vireo differs from several other western breeding passerine species that use desert regions of the southwestern United States and northwestern Mexico to exploit late summer food resources. The areas of these southwestern desert regions used by other species form a small portion of the breeding grounds, and encompass the entire wintering grounds, of Gray Vireos. I hypothesize that this contrast in molting regions is not due to differences in the general timing of prebasic molts among these species; rather, the contrast may be due to constraints imposed on Gray Vireos by a dietary shift to fruit during winter and the need to defend winter territories.

scholarly journals Identification of Linear Vegetation Elements in a Rural Landscape Using LiDAR Point Clouds

2019 ◽  
Vol 11 (3) ◽  
pp. 292 ◽  
Author(s):  
Chris Lucas ◽  
Willem Bouten ◽  
Zsófia Koma ◽  
W. Kissling ◽  
Arie Seijmonsbergen
Keyword(s):  
Regional Planning ◽  
Point Cloud ◽  
Agricultural Land ◽  
3D Structure ◽  
Point Clouds ◽  
Bare Soil ◽  
Agricultural Landscapes ◽  
Rural Landscape ◽  
Conservation Strategies ◽  
Rural Landscapes

Modernization of agricultural land use across Europe is responsible for a substantial decline of linear vegetation elements such as tree lines, hedgerows, riparian vegetation, and green lanes. These linear objects have an important function for biodiversity, e.g., as ecological corridors and local habitats for many animal and plant species. Knowledge on their spatial distribution is therefore essential to support conservation strategies and regional planning in rural landscapes but detailed inventories of such linear objects are often lacking. Here, we propose a method to detect linear vegetation elements in agricultural landscapes using classification and segmentation of high-resolution Light Detection and Ranging (LiDAR) point data. To quantify the 3D structure of vegetation, we applied point cloud analysis to identify point-based and neighborhood-based features. As a preprocessing step, we removed planar surfaces such as grassland, bare soil, and water bodies from the point cloud using a feature that describes to what extent the points are scattered in the local neighborhood. We then applied a random forest classifier to separate the remaining points into vegetation and other. Subsequently, a rectangularity-based region growing algorithm allowed to segment the vegetation points into 2D rectangular objects, which were then classified into linear objects based on their elongatedness. We evaluated the accuracy of the linear objects against a manually delineated validation set. The results showed high user’s (0.80), producer’s (0.85), and total accuracies (0.90). These findings are a promising step towards testing our method in other regions and for upscaling it to broad spatial extents. This would allow producing detailed inventories of linear vegetation elements at regional and continental scales in support of biodiversity conservation and regional planning in agricultural and other rural landscapes.

scholarly journals Vegetation height and cover fraction between 60° S and 60° N from ICESat GLAS data

2012 ◽  
Vol 5 (2) ◽  
pp. 413-432 ◽  
Author(s):  
S. O. Los ◽  
J. A. B. Rosette ◽  
N. Kljun ◽  
P. R. J. North ◽  
L. Chasmer ◽  
...  
Keyword(s):  
Vegetation Cover ◽  
Climate Models ◽  
Soil Cover ◽  
Bare Soil ◽  
Ecological Models ◽  
Tree Cover ◽  
Data Sets ◽  
Vegetation Height ◽  
Height Estimates ◽  
Global Vegetation

Abstract. We present new coarse resolution (0.5° × 0.5°) vegetation height and vegetation-cover fraction data sets between 60° S and 60° N for use in climate models and ecological models. The data sets are derived from 2003–2009 measurements collected by the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008) with with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70 m in 0.5 m intervals for each 0.5° × 0.5°. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r = 0.33 to r = 0.78, decreases the root-mean-square error by a factor 3 to about 6 m (RMSE) or 4.5 m (68% error distribution) and decreases the bias from 5.7 m to −1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5–6 m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a global vegetation height product typically used in a climate model, a recent global tree height product, and a vegetation greenness product and is shown to produce realistic estimates of vegetation height. Finally, the GLAS bare soil cover fraction is compared globally with the MODIS bare soil fraction (r = 0.65) and with bare soil cover fraction estimates derived from AVHRR NDVI data (r = 0.67); the GLAS tree-cover fraction is compared with the MODIS tree-cover fraction (r = 0.79). The evaluation indicates that filters applied to the GLAS data are conservative and eliminate a large proportion of spurious data, while only in a minority of cases at the cost of removing reliable data as well. The new GLAS vegetation height product appears more realistic than previous data sets used in climate models and ecological models and hence should significantly improve simulations that involve the land surface.

scholarly journals Modelling and Delineation of Hydrocarbon Micro - Seepage Prone Zones on Soil and Sediment in Ugwueme, South Eastern Nigeria with Soil Adjustment Vegetation Index (SAVI)

2020 ◽  
pp. 13-33
Author(s):  
Mfoniso Asuquo Enoh ◽  
Uzoma Chinenye Okeke ◽  
Needam Yiinu Barinua
Keyword(s):  
Remote Sensing ◽  
Image Classification ◽  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Bare Soil ◽  
Landsat 8 ◽  
Landsat Images ◽  
Landsat 7 ◽  
Soil And Sediment

Remote Sensing is an excellent tool in monitoring, mapping and interpreting areas, associated with hydrocarbon micro-seepage. An important technique in remote sensing known as the Soil Adjusted Vegetation Index (SAVI), adopted in many studies is often used to minimize the effect of brightness reflectance in the Normalized Difference Vegetation Index (NDVI), related with soil in areas of spare vegetation cover, and mostly in areas of arid and semi–arid regions. The study aim at analyzing the effect of hydrocarbon micro – seepage on soil and sediments in Ugwueme, Southern Eastern Nigeria, with SAVI image classification method. To achieve this aim, three cloud free Landsat images, of Landsat 7 TM 1996 and ETM+ 2006 and Landsat 8 OLI 2016 were utilized to produce different SAVI image classification maps for the study.  The SAVI image classification analysis for the study showed three classes viz Low class cover, Moderate class cover and high class cover.  The category of high SAVI density classification was observed to increase progressive from 31.95% in 1996 to 34.92% in 2006 and then to 36.77% in 2016. Moderately SAVI density classification reduced from 40.53% in 1996 to 38.77% in 2006 and then to 36.96% in 2016 while Low SAVI density classification decrease progressive from 27.51% in 1996 to 26.31% in 2006 and then increased to 28.26% in 2016. The SAVI model is categorized into three classes viz increase, decrease and unchanged. The un – changed category increased from 12.32km2 (15.06%) in 1996 to 17.17 km2 (20.96%) in 2006 and then decelerate to 13.50 km2 (16.51%) in 2016.  The decrease category changed from 39.89km2 (48.78%) in 1996 to 40.45 km2 (49.45%) in 2006 and to 51.52 km2 (63.0%) in 2016 while the increase category changed from 29.57km2 (36.16%) in 1996 to 24.18 km2 (29.58%) in 2006 and to 16.75 km2 (20.49%) in 2016. Image differencing, cross tabulation and overlay operations were some of the techniques performed in the study, to ascertain the effect of hydrocarbon micro - seepage.  The Markov chain analysis was adopted to model and predict the effect of the hydrocarbon micro - seepage for the study for 2030.  The study expound that the SAVI is an effective technique in remote sensing to identify, map and model the effect of hydrocarbon micro - seepage on soil and sediment particularly in areas characterized with low vegetation cover and bare soil cover.

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