Search

Rangeland assessment in the arid and semi-arid regions of Patagonia, Argentina, is a key tool both in livestock management and in environmental evaluations and monitoring of complex processes such as desertification and the impact of climate change. Although most rangeland assessment methods have assigned efforts to data resolution (field assessment plots) or information extension (landscape-scale classifications using remote sensing), the temporal variation of the vegetation has received less attention. It can be argued that the reasons for this deficit respond to the cost of carrying out field evaluations over time and/or to the short series of satellite data available until a couple of decades ago. However, a current advantage is that there are already more than 20 years of satellite data series, which opens up new possibilities to guide greater efforts in the study of the dynamics, that is, the temporal and spatiotemporal variability of the vegetation productivity. Our objective was to evaluate the application of a vegetation functional classification method, analyzing the complementation of information between structural and functional aspects of rangelands at a farm scale. In particular, we compared the results obtained by a classification of landscape units and physiognomy of vegetation and the results of a classification with a characterization of the dynamics of the vegetation productivity from the protocol that we have called Rangeland Functional Archetypes. The results emphasize the need to incorporate the dynamics of vegetation productivity as a classifying factor and not as a dependent variable of a previously defined structural classification. We discuss the potential and future steps to move forward in the integration of both approaches at the farm scale in the livestock systems of Patagonia, as a tool for a complementary structural and functional assessment of rangelands, oriented towards planning and adaptive management. [ABSTRACT FROM AUTHOR]

The Mira River basin is considered a socio-ecological mosaic. However, the productive and economic dynamics of the area have been the main activities that have endangered its richness and endemism. This study determines how changes in vegetation cover inflence the potential distribution of Croton wagneri Müll. arg. (Müller, 1872), using Landsat satellite images of the years 2010 and 2018 as inputs in a maximum entropy model (MaxEnt), together with environmental variables. The results obtained show that during the study period there were losses of forest cover (2.26%), shrub vegetation (3.24%), xerophytic vegetation (1.72%) and an increase in crops (3.73%), pastures (1.93%) and urban areas (0.38%). This is how changes in land cover significantly influence the potential distribution of the species, since the areas highly suitabale in the period 2000-2010 occupied 0.80% of the surface area, covering parishes such as San Miguel de Ibarra, Ambuquí, Salinas, San Vicente de Pusir, Juan Montalvo and La Concepción, while in the period (2010-2020) this area reduced to 0.19%. These results highlight the importance of implementing conservation measures to protect the local biodiversity. [ABSTRACT FROM AUTHOR]

In 2000, a massive die-off resulted in a drastic reduction of the guanaco (Lama guanicoe) population of Cabo Dos Bahías Reserve, Chubut, Argentina. This event became an emblematic example of guanaco population dynamics in which it is presumed that the lack of regulatory mechanisms induced a population excess that damaged forage resources to an extreme that the population crashed due to starvation. Although this case poorly represents the relevant ecological scenarios, it has a disproportionate influence on current debates regarding the management of guanaco populations. Some authors even claim that, unless guanaco populations are culled, this degradation process will propagate across Patagonian rangelands. In this paper we aimed to synthetize the available evidence and to socialize the results obtained after 15 years following guanaco and vegetation dynamics at Cabo Dos Bahías to contribute to the discussion on the causes and consequences of mentioned guanaco die-off. The available evidence shows that population density is compatible with forage availability and it is coupled with its inter-annual variability. Range condition at the reserve is similar or better, upon the indicator considered, than range condition at neighbouring ranches with traditional livestock management. Our analysis indicates that, although Cabo dos Bahías presented high guanaco densities, which fluctuated more than other populations, there is no evidence to support the lack of regulation, population excess or environmental damage. Finally, we discuss our results in the context of the current debate about guanaco management in Patagonia. [ABSTRACT FROM AUTHOR]

This work presents the first paleobiogeographical study of the forests of the Sierra del Tablón, one of the northernmost mountain massifs of the Serranía de Ronda (Spain) and the highest point in the province of Seville at 1,129 m a.s.l. The mesological approach is used to analyse the physical characteristics of the mountain massif (geology, geomorphology and climate). Study of past and present vegetation is also addressed, identifying the dominant plant formations and their evolution since the mid-twentieth century, with particular attention to the forest facies representative of the climax stages. Finally, the results of the pedoantracological analysis carried out in the study area are included, which enables us to delve into the dynamics of their vegetation by carrying out two pedological samples. [ABSTRACT FROM AUTHOR]

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Deforestation is one of the most critical problems facing humanity. Ecuador is one of the Latin American countries with the highest rate of forest clearing compared to its size, mainly due to the increase in agricultural area. The objective of this work was to determine the dynamics and changes that have occurred in the agricultural frontier in the last 30 years in the hydrographic basins belonging to the Zapotal using remote sensing tools. The images were obtained from the Sentinel 2 and Landsat satellites from 1990 to 2020. The free QGIS software was obtained to analyze, classify and process the satellite images; Through a confusion matrix and the kappa index, precision was evaluated. High-quality satellite images and resolutions corresponding to the period from 1990 to 2020 will be needed and processed. The Normalized Difference Vegetation Index (NDVI) allowed us to know the dynamics of the vegetation conformation of the studied period and, consequently, the uses of the soil depending on the vegetation cover. The dynamics of the agricultural frontier, determined through the remote sensing tools used in this study, shows a decrease of approximately 15%. The methodology used in this study will prove to be effective and economical to understand the dynamics of the agricultural frontier, which provides an effective tool to monitor, plan, and execute various territorial planning and local development projects. [ABSTRACT FROM AUTHOR]

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Migraciones is the property of Universidad Pontificia Comillas, Instituto Universitario de Estudios sobre Migraciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural forest´s covers are changing due to the spread of the urban, agricultural and livestock frontier, affecting the availability of shelters and resources for the breeding of birds. Despite our knowledge of the influence of anthropic interventions on biodiversity, investigations that show the anthropic effect on natural history of birds, included the breeding phase, are limited. To describe the anthropic effect on nest predation, 108 artificial nests were established in an anthropic intervention gradient in the jurisdiction of Leticia, Amazonas, Colombia. The 38 nests that were predated, six were in the site with the least anthropic intervention, 15 in the intermediate intervention site and 17 in the site with the highest intervention. In particular, the effect of changes in the vegetation cover mediated by anthropic disturbance on bird nests is assessed, expecting that denser vegetation cover around the nest will positively affect the nest success. Variables associated with the structure of the vegetation near the nests (e.g., Coverage around the nest, low vegetation cover, canopy opening), showed a significant positive relationship with the destination of the nest. This research suggests that the ongoing urbanization process (e.g., house construction and roads) in the Amazon region influences loss of artificial nests, and that changes in the structure of the vegetation mediated by the degradation of natural covers could play a fundamental role in the predation of nests. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Alternative Biome States theory (ABS) helps to explain the presence of open biomes (grasslands, shrublands) in environments sufficiently warm and humid for the development of forest biomes. In these environments it is possible to find areas dominated by open biomes that, according to this theory, respond mainly to fire and herbivory. The aims of this work are to identify whether there are different types of forest biome-open biome ecotones based on woody composition, describe them and explore their relationship with livestock management and environmental variables, using a protected area in Uruguay as a case study. We sampled woody vegetation and other environmental variables in transects (delimited in 200m) in 10 sites across four livestock management systems. We identified two types of forest biome-open biome ecotones, one dominated by shrubland and the other dominated by grassland. Our results agree with the ABS theory and suggest the mechanisms determining the woody composition and the structure of the ecotone vegetation are cattle and use of fire and/or rotary cutter. The changes in vegetation structure and woody richness were partly abrupt, which is consistent with what is proposed by the ABS theory. However, the composition also interacted with site factors such as rockiness and distance to the watercourse, suggesting that site-level environmental variables are acting synergistically with vegetation removal to determine vegetation composition. We found that these ecotones are sensitive to management and environmental variables; so, it is necessary to incorporate this landscape and site heterogeneity to articulate productive activity with nature conservation. [ABSTRACT FROM AUTHOR]

Climate and anthropogenic factors control vegetation dynamics, and its study provides indicators to address the multi-scale analysis of environmental trends. In this article, an inter-annual analysis of NDVI 2000-2020 trends in Andalusia was conducted using the MODIS Vegetation Index Products. The main findings show: 1) the annual median NDVI showed a significant trend (p-value <0.05) in 42% of the study area, with significant increasing trends of 95.5%; 2) the annual median NDVI showed a significant trend (p-value <0.05) in 44.1% of the study area, with significant increasing trends of 93.1%; and, 3) the annual median NDVI showed a significant trend (p-value <0.05) in 64.9% of the study area, with significant increasing trends of 98.4%. This greening trend was found both in agricultural and forest covers. However, this greening was more relevant in some land cover types: olive groves and fruit trees; and sclerophyll scrubs with scattered trees and forests. The findings suggest the importance of anthropogenic factors and how they interact with climate change, while also cautioning against the limitations of vegetation greening. [ABSTRACT FROM AUTHOR]

Copyright of Investigación Agraria is the property of Investigacion Agraria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There are more than 4 billion hectares of forests in the world, which corresponds to 31 % of the surface of our planet. In Chile, 17 million ha of forests cover the country where more than 3 million correspond to plantations. The role of vegetation cover in the dynamics of precipitation, in the generation of runoff and in the protection and conservation of degraded land is known. This cover plays an important role in the hydrological cycle and its balance, especially in the north central zone to the south. A new impulse is required in research, both from the Government and the private sector, as well as reformation to public policies, thus articulating research in forest hydrology with an imperative sense of integrality. Therefore, this document presents a proposal for the development of research in forest hydrology with an integral and decentralization approach. Highly capable scientific human capital in Chile, organized in geographically defined nuclei, would be capable of answering relevant research questions in forest hydrology that would support public policies based on scientific evidence. All this, under the auspices of a technical integrating entity to allow a fluid conversation and discussion of the actors of the forestry sector, both in research matters and in the generation of public policies from an integral and multidisciplinary perspective at the catchment level. [ABSTRACT FROM AUTHOR]

The autumn of 2021 in Spain was thermally normal but the coldest since 2012. Precipitation was generally scarce, being below normal in some regions such as Andalusia, Murcia, Galicia, and Extremadura. There was meteorological drought in some areas of the Canary Islands, Galicia, and Andalusia. The grape harvest started early in some regions, but intermittent rains affected the quality of the grapes. Snowfall in the mountains of the northern peninsula and floods in some places are also mentioned. Additionally, changes in vegetation and fauna during these months are described. [Extracted from the article]

An experiment was carried out to evaluate the effects of grazing rest on the vegetation structure, the hydrological function, and the ecological status in grasslands of regular condition for cattle. The study area is located at 4 095 meters above sea level, in the Cordillera Blanca peasant community, Ancash Region, Peru. The experimental design was factorial 2 x 2 in blocks, where the factors were: a) two grazing systems P1: Uncontrolled grazing on communal usufruct lands and P2: Rest or total exclusion of grazing, and b) three years of monitoring between 2011 and 2013. At the end of the study, the vegetation structure changed according to the regime of the rangeland use, where the rest favored the increase of native gramineae species and to the detriment of herbs, pseudogramineae, and shrubs. Resting increased the vegetation cover, the accumulation of biomass and mulch on the ground with respect to grazing (P < 0.01). The hydrological function improved with the application of rest compared to grazing, which was reflected in a higher infiltration capacity and soil moisture content (P < 0.01). The ecological processes improved with resting compared to grazing expressed by the increase of the ecological status of the pasture, in response to the improvement of the components that determine its value, such as forage species and vigor (P < 0.01). [ABSTRACT FROM AUTHOR]

The fragmentation of aquatic and riparian environments has damaged diversity into ecosystems. These injuries are pronounced in areas as tropical dry forests in Colombia, which are endangered zones that could be disappear in few years. In this situation, diversity and composition in Odonata insects, which are influenced by abiotic factors, could be excellent tools for understanding environmental status. Thus, we aim to observe changes in Odonata diversity and composition in different riparian vegetation during a year, along a stream from a remnant of dry forest. At the same time, we hypothesize that there are differences in Odonata diversity and composition. To take this, we sampled Odonata, larvae and adults, and environmental variables in four sampling stations, with different riparian vegetation during a year. We collected a total of 272 specimens corresponding to 16 species. In one hand, we noted variations in Odonata composition, showed in species records and similarity index. In other hand, we do not observe differences in Odonata diversity. Lastly, we approve in part our hypothesis exposing only Odonata composition changes with riparian vegetation, during sampling year. [ABSTRACT FROM AUTHOR]

Genista longipes Pau is part of orophile pulvinular baetic scrubs, one of the one of the plant communities most vulnerable to global warming. Its easternmost distribution in the Iberian Peninsula is located at the culmination of the Serra d'Aitana (Alicante), considered a refuge of extreme fragility in the face of any climatic alteration. In 2004, a detailed corological cartography was made with the distribution of the species in the eastern sector of the sierra, preferably from 1475 mamsl, registering a small isolated subpopulation at 1300 mamsl. To try to understand this disjunct location, the Thermicity Index has been calculated for squares of 200 m on each side in order to determine the extension and subdivision of the supra-Mediterranean level, modeling a scenario of increased temperatures that would cause its extinction. To verify this hypothesis, since 2014 a follow-up is carried out through an exhaustive fieldwork with centimeter accuracy GPS. The results show controversial data, since the population increased significantly between 2004 and 2014 and is in a sustained decline from 2014 to 2018. The value of temperature is discussed as the only variable to be treated and the need to analyze the role of wind and the historical management of vegetation to understand its dynamics. [ABSTRACT FROM AUTHOR]

Coastal wetlands of Peru are important because of the multiple services they provide to surrounding towns. To protect these ecosystems, it is important to monitor their areas and the changes that occurred in them. Los Pantanos de Villa is a Ramsar wetland in the city of Lima, and, like many coastal wetlands in the region, has undergone multiple natural and anthropogenic changes. In this work, high and medium resolution satellite images were used (such as WorldView 3 images dated May 2018 and CBERS2, 2B and 4 from 2004, 2008 and 2018) with the objective of defining, identifying and characterizing vegetation units and the analysis of changes in vegetation cover in the area using the NDVI (Normalized Difference Vegetation Index). The methodology included obtaining and acquiring satellite images, basic and thematic cartographic information. These were sometimes a geometric correction, reality techniques and algorithms of classification and obtaining of the NDVI; all this using the ARGIS software and making multiple field outputs. As a result, 8 vegetation units were identified that correspond to the gramadal, totoral, intervened area-bodies of water, juncal, short-cut, aquatic, carrizal, and salicornial. The result obtained from the NDVI analysis indicates that the area without vegetation went from occupying 1.96 ha in 2004 to occupying 38.75ha in 2018; the mixed vegetation class went from 100.24 ha in 2004 to 148,344 ha in 2018; Dense vegetation class went from 130,146 ha to 40,285 ha in 2018. The increase in the area without vegetation is a sign of how the change in land use, due to different human activities, can affect a coastal wetland. [ABSTRACT FROM AUTHOR]

Copyright of Boletín Científico Centro de Museos de Historia Natural is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Geospatial analysis, based on comparative studies of satellite images through geographical information systems, has allowed to highlight territorial changes generated by the interaction between natural morphological processes and anthropogenic activities. The Grijalva-Villahermosa sub-basin is part of one of the largest watersheds in Mexico, the Grijalva-Usumacinta basin. Based on geographical location and geological characteristics Grijalva River is formed by sediments of recent quaternary alluvial Holocene. Geomorphology corresponds to the fluviodeltaic plain with an almost flat slope, so floods are constant. In order to evaluate the effect of water control systems in the dynamics of the fluvial terraces an environmental assessment was developed, taking into account the effect of flood mitigation structures. The fluvial terraces were identified through spectral analysis of 2011 LiDAR images and verified through photo-interpretation and field visits. The environmental assessment was based on Landsat images 1986 and 2016, to which the analysis of change trend with Markov chains was applied. The environmental criterion of the analysis was based on the evaluation of change on the vegetation coverage, wetlands, water bodies, soil and anthropic infrastructure. The most significant results on the dynamics of the fluvial terraces in terms of surface gain occurred in wetlands with 13034 ha and a loss of 6475 ha, in anthropic infrastructure gaining was 3242 ha and losing 3793 ha, as well as a gain of 1145 ha and a loss of 3519 ha in water bodies. The results showed an intensive change trend in wetlands coverage on the analysis period. The current dynamics in the Subbasin shows a regular behavior in the formation of the fluvial terraces, but a negative impact due to anthropic factors. [ABSTRACT FROM AUTHOR]

Chaco vegetation is conditioned by several environmental pressures affecting the physiognomy of the landscape. With the aim to recognize the spatial changes of vegetation and distinguish indicators of natural (floods, droughts) and/or anthropogenic disturbances (fires, weeds of crops and grazing), we analyzed the composition and distribution of pollen assemblages of surface sediments along an environmental in the north of Argentine Chaco region (23°-27° S, 59°-63° W). Thirty-five samples were taken into an environmental gradient comprising 600 km length in SE-NW direction. The analyses was performed by multivariate methods and the importance value index (IVI). Zonation showed a gradual replacement of biotypes and taxa. In the Eastern zone, the pollen of palms (Copernica alba), herbs (Poaceae) and high trees (Schinopsis balansae) were dominant. Towards the middle zone, the pollen of low trees (Schinus, Prosopis ruscifolia, Pisonia zapallo), shrubs (Celtis, Castela) and herbs (Amaranthaceae/Chenopodiaceae, Poaceae) were dominant. The western zone recorded the highest content of pollen of high trees (Schinopsis balansae, Schinopsis lorentzii, Astronium). Pollen types were detected that allowed to discern environmental contingencies, such as floods (Copernicia alba, Juncaginaceae, Cyperaceae) and anthropic activities, such as fires (Trithrinax, Shinus, Aspidosperma quebracho-blanco), weeds of crops (Amaranthaceae/Chenopodiaceae, Gomphrena, Urticaceae, Ambrosia) and grazing (Prosopis ruscifolia, Prosopis kuntzei, Capparicordis, Cerciduim praecox). The most important pollen types were: Schinopsis balansae (9 %), Celtis (8.4 %), Poaceae (7.5 %), Schinus (6.9 %), Copernicia alba (3.7 %), among others. Three pollen assemblages were differentiated which represent the follow communities: 1) palms and savannas, 2) low forests and scrublands and 3) high forests, that are distributed in precipitation thresholds corresponding to, 1 100 - 1 000, 1 000 - 850 and 850 - 700 mm respectively. Results expand the knowledge about the pollen assemblages of the Argentine Chaco region, offering a good perspective to interpret the dynamic of the landscape during the Holocene in the region. [ABSTRACT FROM AUTHOR]

Ecological restoration of forest in desertified lands, where the soil has been seriously damaged by erosion, is a long-term process. Understanding this process requires an exhaustive analysis of the forest structure, composition and function, and the actions necessary to reach the appropriate ecosystem. We analyzed a fifty year-old hydrology-forest restoration in central Spain, using an ecological forest restoration framework with phases of forest cover rehabilitation and subsequent monitoring and follow-up. Although full recovery the previously existing oak forest is still a longer-term goal, the short-term establishment of a pine forest has helped to restore ecosystem function and to mitigate serious erosion problems. The establishment of pine forest allowed progress in reconstituting the soil, introducing native oak seedlings, and regulating the hydrological cycle. [ABSTRACT FROM AUTHOR]

In this study we address the relationship between climate and vegetation in the territory of the Mexican Pacific rim, a strip of 100 km wide that extends from the coast landwards with its north and south limits coinciding with Mexico's border with the United States of America and Guatemala, respectively. Relationships were established from bioclimatic analysis performed with temperature and precipitation data from 691 weather stations existing in the study area. The bioclimatic diagnosis identified the Mediterranean and Tropical macrobioclimates, the Mediterranean Pluviseasonal Oceanic, Mediterranean Xeric Oceanic, Mediterranean Desert Oceanic, Mediterranean Hyperdesertic Oceanic, Tropical Pluvial, Tropical Pluviseasonal, Tropical Xeric, Tropical Desertic and Tropical Hiperdesertic bioclimates, and 30 isobioclimates. The field sampling was focused towards physiognomic and floristic characterization of the natural potential vegetation of the different bioclimatic units, thereby establishing the main diagnostic features (bio- indicators and physiognomic-structural elements) of the bioclimatic sequence along the latitudinal gradient. [ABSTRACT FROM AUTHOR]

The Chemical composition ( pH, elements major and minor, % S.B., CIC, % M.O. and N.T) on soils in open areas and forest fir (Abies guatemalensis Rehder ) in a successional gradient was studied. These results were related to vegetation through correlation analysis and Canonical Correspondence analysis. The aim was to show the relationships present between vegetation and soil chemistry through ecological succession in areas of cold climate. The results indicate that the vegetation is composed of 82 species of which 20 are the lower herbaceous layer, 34 the herbaceous layer of the upper, 21 shrubs and seven trees. The chemical characteristics of the soil through five successional stages have only few significant differences and not show a clear tendency to increase according to the degree of ecosystem development. A low percentage of correlations between vegetation and soil chemical characteristics are presented. The correspondence canonical analysis shows that the features that correlate with sites through vegetation are the K, and % S.B. and CIC. One can conclude that the approach of the study of the chemical composition of soils in areas of ecological sequence is complex, especially in high regions where, besides other factors, the temperature and humidity play an important role on the soil-vegetation dynamic. [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The values of green biomass (Bv) measured in a grassland were associated with index values of normalized difference vegetation index (NDVI) from satellite data in three relict natural grassland on stream Chucul, from his beginning site 1 (32 49'21, 0 '' S and 64 ° 24 '07.0 '' W) until its demise in plain area: site 3 (33 ° 06' 25.5 '' S and 63 ° 32 '49.1 '' W). Under the hypothesis of correspondence of Bv and data obtained by images, the aim of this work is to determine the relationship between measured field data and satellite data in natural grasslands. Seasonally during the 2009-2011 cycle were sampled at random with 10 replicates of 0.25 m² recording floristic list. To determine Bv in each plot the biomass was cut and separated in green and dry compartments and dryed to constant weight. For digital analysis bands 3 and 4 of Landsat 5 TM image (Path 228 Row 083) were used for each site close to the sampling date. The highest values of green biomass were determined for site 3, in December 2011: 189.6 g/m² and in March for sites 1 and 2: 105.74 and 115.22 g/m². Among all the observed values of biomass and NDVI estimated the correlation coefficient was highest at site 3 (R = 0.50). The results of the work for site 3 validate the hypothesis and indicats of the aptitude of digital images for study the status and changes in vegetation. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Entomología is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present an approach to the dynamics that determine current distribution of vegetation in the semiarid enclave Canyon Chicamocha River (Pescadero sector). The disturbance regime determine different successional patterns in a high spatial and temporal heterogeneity. The main types of dynamics and vegetation changes are related to disturbances such as landslides or soil removal in hillside areas, grazing goats estabulizado not, agroecosystems Quaternary terraces and fluctuations in river levels. In the case of landslides are different processes in succession high slopes areas and in areas of low slopes. We evaluated areas with primary successions submitted after landslides and river fluctuations, secondary successions agricultural product, and estate regeneration on slopes with grazing goats. The grazing of goats is a continuous disturbance and more decisive in the transformation of plant communities for loss of tree elements and increasing the abundance of unpalatable species. We found that on the slopes overlooking Lippia origanoides, forming extensive homogeneous matrix and mixed with patches of Prosopis juliflora and Stenocereus griseus slopes at the base of sloping floor or cones produced by landslides. The use of agricultural land on slopes low and terraced dynamics is related to the types short cycle crop. The dynamics associated with seasonal fluctuations in the water level of the river Chicamocha generates colonizing of short life cycle species and low requirements in structuring their micro-habitat. Finally, we present a conceptual model for the interpretation of the dry forest degradation and its relationship with the aridity phenomena. [ABSTRACT FROM AUTHOR]

Copyright of Revista Luna Azul is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A states and transitions model is presented for the Laguna Blanca National Park wetlands. For the description of the states, vegetable community characteristics, such as dominating life form, coverage, and floristic diversity; soil characteristics, as texture, pH, and salinity; and geomorphologic characteristics were used. The combined action of variations in hydrologic regime and wetland management (continuous grazing) has promoted changes in the original vegetation, which allowed four states to be described-grouped in hydrophytes, mesophytes, halophytes, and xe­rophytes, and six transitions to be considered. From the tendencies observed, we can conclude that the states show different stability to continuous grazing. Prolonged drought and consequent system salinization affects the ecosystem forage diversity and productivity. It can be established that the system currently maintains itself due to lateral water recharge and local precipitation, which would imply that, if the perturbation continues, there will be a decrease of hydrophytes and mesophytes prairies, and an increase of halophytes and xerophytes [ABSTRACT FROM AUTHOR]

River floodplains have a high biological diversity that is intensely influenced by vegetation dynamics, changes in space and time scales, and the river`s hydrological regime. The vegetation composition of the medium and lower Paraná River has been analyzed previously, with different approaches and criteria that cannot be compared. The aim of this study is to analyze the diversity of the herbaceous vegetation over long time spans, from its regeneration after a catastrophic flood to its recovery, in the North and South sites of the flooding valley of the Medium Paraná River. The first sampling of a pioneer community was performed after the 1982-83 catastrophic flood, and included the surveillance of two plots in two successive recovery stages. Floristic composition and cover-abundance of all species were recorded per plot. Floristic richness, using jackknife, Shannon and Hurlbert diversity and Simpson dominance curves were calculated for each site and for each survey, using EcoSim (software). Floristic richness was higher in the North of Medium Paraná, while dominance was higher in the South. Diversity indexes did not varied significantly and resulted in relatively stable values, because its components compensate each other. [ABSTRACT FROM AUTHOR]

The objective of the study was to assess the capacity of vegetation to reduce the noise in the Aburrá valley. The methodology comprised two phases: the first was the revision of secondary information related to the role of vegetation and to obtain the conceptual bases for further experimental development. The second phase was the measurement of noise levels 10 m from the sound source (high traffic road) in urban public green zones with different plant coverage (tree, shrub, and a mixture of trees and shrubs) and without vegetation. Results showed no significant differences between the sites with and without vegetation, allowing us to infer that under conditions of the study, characterized by having few individuals of trees and shrubs dispersed, the vegetation does not play a significant role in reducing noise. Therefore, for its control in urban areas measures other than the planting of trees must be taken, or wider, longer, denser, and higher live barriers should be established. [ABSTRACT FROM AUTHOR]

Introduction. In the last years, the incursions and domiciliary populations of Panstrongylus geniculatus Latreille 1811 have increased in Venezuela. Objective. To analyze the P. geniculatus introduction in homes of the center-north of Venezuela, relating it with peri and intra-domiciliary macro and micro ambient, characterize interaction with human and domestic animals and the Trypanosoma cruzi natural infection index (TcNII) is evaluated. Materials and Methods. Captures of P. geniculatus in the center-north of Venezuela (Caracas and Aragua, Miranda and Vargas states) are related with the macro-environment (altitude, humidity, temperature and precipitation); the home (housing type-color, type-color of external illumination and it distances to the forest); inhabitants' density and housings; percentage of vegetation; housings distribution in the space of and public illumination. The interrelations are analyzed with ANOVA, Multiple regression and Lineal Regression Forward Step Wise, and satellite images. The triatominebites to humans are correlated with abundances of potential sources of blood ingestion (human and/or animal). The TcNII was determined in triatomine feces. Results. In the center-north of Venezuela the presence of P. geniculatus during the evening, in the area to be domiciled related with: vegetation <21%, temperature 24-26°C, HR50-80%, number of animal/housing >5 and number people more animals/housing ≥13. From 1906 interviewed people, 159 had contacted with P. geniculatus being 86 triatomine-bitten. The TcNII was between 20 and 100%. Conclusions. The presence of P. geniculatus adults during the evening was independent of the housing type, increasing with the decrease of: % of vegetation, domestic animals, distances from the forest and when the lights were on. [ABSTRACT FROM AUTHOR]

In order to study gene flow between common wild and cultivated cultivated bean, the rate of allogamy was estimated in a location where wild common bean grows naturally and at an experimental station. In 2004, natural outcrossing between wild Mexican bean G23511A (Phaseolus vulgaris L.) and white cultivar PAN68 was estimated at Fabio Baudrit Experimental Station of the University of Costa Rica in Alajuela. Two experimental plots were sown; each one had two blocks of ten rows of PAN68 (15m long and 0,6m spaced). Between blocks and at their upper border, three rows of wild Mexican common bean were sown as pollen donors. Each of the rows and plants in the white blocks was numbered. In 2005 and 2006 in Quircot, Cartago, where wild common bean grows naturally, plants of common bean (Vainica de Palo) were sown in six locations adjacent to wild common bean populations. In both locations, flowering of wild and cultivated bean was coincident. All seeds from assays were harvested and germinated in seedling trays, estimating the rate of allogamy through the color of the hipocotyl (purple), which indicates what seedlings were crossed. In Alajuela, natural crossing ranged from 0,007 to 0,028 %, whereas in Quircot from 0 to 0,199 %. [ABSTRACT FROM AUTHOR]

Copyright of SHILAP Revista de Lepidopterologia is the property of Sociedad Hispano-Luso-Americana de Lepidopterologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Corredor Biológico Chichinautzin is a natural protected area with an extension of 65,901 ha. Within its boundaries seven vegetation types are represented in an altitudinal range from 1200 to 3400 m. Revision of herbarium collections and bibliography, and field specimens collections, let us to obtain the inventory of native monocots species present in the area. the inventory comprises 359 species, 132 genera and 25 families. Orchidaceae and Bromeliaceae stand out by their endemism level. In the area grow six exclusive species. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Coastal ecosystems of Lomas are constituted by plant communities developing under winter fog influences. In order to explore this issue we determined the relationship between vegetation dynamics and meteorological conditions at Atiquipa Lomas, Barrera and Lagunillas hills (15°46′ LS y 74°22′ LW, 800 m.a.s.l. aprox.) from February 2005 to February 2006. Forty-five 0,5 x 0,5 m plots were installed in each hill, with monthly plot evaluations of species number, individuals per species (seedlings and adults), species cover, fallen leaves cover and phenological status. Simpson and Shannon--Wiener indexes were calculated. Natural precipitation, fog collection and medium temperature were also monthly registered. With these data we ran lineal correlations between environment parameters (3) and vegetation (10). Several significant relationships (p<0.05) were found, fog had 5 significant relationships: direct with total individuals in Barrera (r=0.79), with seedling emergence in Barrera (r=0.79) and Lagunillas (r=0.77), and with Simpson's predominance in Barrera (r=0.65), and inverse with Shannon-Wiener's diversity in Barrera (r=-0.76). There was an inverse relationship between temperature and predominance in the community (Barrera r=-0.61; Lagunillas r=-0.59). Natural precipitation did not show any significant relationships, although a cumulative effect between July and August which unleashed seedling emergence in September can be suggested. More research concerning these relationships is necessary, especially in a climate change scenario which could affect moisture regimes in these dynamic fragile ecosystems. [ABSTRACT FROM AUTHOR]

The forests of the northeast Yucatan Peninsula supports wild ungulate populations such as the white-tailed deer (Odocoileus virginianus (Hays 1874), brocket deer (Mazama americana Erxleben 1777 and M. pandora Merriam 1901) and collared pecari (Pecari tajacu Merriam 1901). For its conservation and use, it is necessary to know the current status of wild ungulates populations. Basic ecological aspects such as density and distribution of the ungulate populations in different vegetation types were evaluated. The study area was El Edén Ecological Reserve (EER), located in the northern Yucatan Peninsula in Quintana Roo State, Mexico. The method used to assess ungulate density and distribution was the strip transect counts. The transects were set on the existing roads and footpaths. Using GIS, the habitat and five vegetation types were classified: secondary vegetation (acahual), tropical evergreen forest, tintales, savanna of palms and aquatic vegetation. Thirty eight observations of white-tailed deer were obtained, 14 of brocket deer and 6 groups of pecaries in 293.4 km of routes. The observation period was between September 2004 and April 2005 (six months of sampling). The absolute density of the white-tailed deer was 5,5 ± 4,1 ind/km², for the pecan was 1,9 ± 0,8 ind/km² or 0,2 ± 0,1 herd/km² and for brocket deer was 1,7 ± 1,8 ind/km². Acàhual was the vegetation type where white-tailed deer and collared pecan were found. This is the first time that AL americana was registered in this region of the State. These results suggest the important role that have the EER to conserve ungulates, nevertheless the continued risk of hurricanes and fires. The white-tailed deer population is high compared with other tropical zones. [ABSTRACT FROM AUTHOR]

The feasibility to obtain quality agricultural products, irrigated with saline water, makes it necessary to assess areas peripheral to the irrigated oasis in order to determine their suitability for cropping. The goal is to combine diverse methodologies for mapping and assessing ecologically homogeneous units in marginal lands of Mendoza, using plant communities as an indicator of these units. A pilot area was surveyed using LANDSAT/TM image processing, and vegetation, soil and water table were analysed. Assessed vegetation units and their respective salinity ranges (dS m-1), up to 50 cm depth, were: steppe of Heterostachys ritteriana, 91-83; shrubland of Allenrolfea vaginata with H. ritteriana, 83-48; open shrubland of A.vaginata con Prosopis strombulifera, 62-55; open steppe of Suaeda divaricata with Atriplex argentina, 52-83; shrubland of S. divaricata con Lycium tenuispinosum, 40-43; open woodland of Prosopis flexuosa, 37-26; dense shrubland of Prosopis alpataco, 7-6. The concentration of soluble salts exceeds the critical levels tolerated by cultivated plants. No water tables were detected within 15 m from the surface. It is considered that soils have good drainage conditions, so they can be recovered without high investment. This methodological approach showed good correspondence among plant communities, their spectral expression, and soil salinity and drainage conditions. [ABSTRACT FROM AUTHOR]

A very quick regression of vegetation cover after hydroseeding application was reported by previous studies in steep road cuts on marls in submediterranean areas of Navarra. However some local species are able to colonize these surfaces. The colonization ability of these species supplied by seed rain was determined to test if they are constrained as sown species are. Their spatial distribution was also described to check their source of propagules. Despite the abiotic constraints in the slopes, local species were able to establish in low densities. On the other hand, most species decreased as the distance to the upper part of the slope increased. These results point out the relevance of the vegetation placed over the slope as seed source. [ABSTRACT FROM AUTHOR]

Vegetation and floristic composition of the Pachachaca basin, located in north western Huancavelica were studied from 2001 to 2003. There were registered 180 species belonging to 57 families. Herbaceous life forms dominated over other life forms, and only a few native tree species were registered. Eight representative natural plant formations were identified between grasslands and humid, compact slow-growing vegetation named oconales in the high areas, and shrub vegetation almost all over the basin. Floristic composition shows a large richness in species. Asteraceae were most representative in the middle and lowland areas, Poaceae in the high lands, and Fabaceae in the middle and lowland areas of the watershed. [ABSTRACT FROM AUTHOR]

Few studies of vegetation conducted in arid zones have associated soil factors with plant associations. In our study we try to understand which are the most important soil factors that affect composition, distribution and structure of the community. The cacti community was studied at Umarcata Hill and Orobel Valley of the Chillon River Basin. A simple random sampling was carried out in square 15 meter sided plots, with 14 plots per area. Every area was divided into three zones: high, medium and low. Soil samples were analyzed to determine potassium, phosphorus, and organic matter concentration, pH, electrical conductivity and calcium carbonate percentage . The diversity values at Umarcata Hill lie in the rank from 0.75 to 1.789 bits / individual, whereas in Orobel Valley they rank from 1.22 to 1.88 bits / individual. In the latter, specific diversity and equity are higher indicating a stable and organized community. Phosphorus (15 to 42 ppm) and potassium (300 to 800 ppm) are the factors that limit cacti growth in the community. Electric conductivity (0.3 dS/m) is related to diversity due to the fact that it measures soil salinity, which in turn affects plant growth. [ABSTRACT FROM AUTHOR]