The Yucatan Peninsula is included as part of the initiative for the Mesoamerican Biological Corridor. In its central area, are located three Protected Natural Areas (PNA): the Biocultural Puuc Reserve (RBP, by its Spanish acronym), the Bala’an K’aax flora and fauna protected area (APB, by its Spanish acronym), Quintana Roo, and the Calakmul Biosphere Reserve (RBC, by its Spanish acronym), Campeche. The Puuc-Chenes region is located in the center of the Yucatan Peninsula - among these PNAs - which included important fragments of vegetation that in the past formed a continuum through the forests of the Yucatan Peninsula, constituting an important link to keep the connectivity of the Mayan forest. However, the expansion of the agricultural frontier is causing the fragmentation of the habitat. In the present study, the structural and functional connectivity of the Puuc-Chenes region is analyzed, based on habitat requirements of the Panthera onca (jaguar) by sex. Both, male and female, prefer tropical forest, however, P. onca males dare to transit in secondary vegetation and inclusively in agricultural areas. Males make inroads to villages more often than females, coming close to, and even crossing roads. P. onca males have a home range of 60 km2. In the present study, the ArcMap, FRAGSTATS and IDRISI software were used to analyses the structural and functional connectivity of the landscape, based on the known differences of habitat requirements for P. onca males and females. A vegetation and land use map of the studied area was elaborated, based on Landsat 7 ETM+ images, with 30 m size pixels. The following cover classes were differentiated: tropical forest, secondary forest, agriculture, urban, and water polls, which were validated in the fields. The Puuc-Chenes has an extension of 972 578 ha. Tropical forest was the dominant vegetation cover (49.8%) with the largest patch index covering 19.7% of the total landscape. The landscape had 2 509 fragments, from which 1 254 y 935 corresponded to secondary forest and anthropic patches, respectively. The contagion index was 62.5%, which indicates the existence oflarge and contiguous fragments. The total edge contrast index indicates the degree of landscape connectivity was 43.7%, meaning a medium contrast among the different class fragments. Likewise, forest had the highest area-weighted mean proximity index (PROX_AM de 8 701), confirming that the forest had bigger and less isolated fragments than the rest of the classes. The area of study, still have high value for the conservation of the habitat of the P onca. According to the results, we conclude that the Puuc-Chenes region has intermediate structural landscape connectivity, since a suitable corridor was identified for males and three corridors for both, males and females. Four priority fragments of forest were identified in the Puuc-Chenes landscape to be protected: the Puuc fragment with 1 916 km2
{"title":"Evaluación de la conectividad del paisaje en la región Puuc-Chenes, México, con base en los requerimientos de hábitat del jaguar (Panthera onca)","authors":"Eduardo Salazar , Jorge Mendoza , Susana Ochoa-Gaona , Víctor Ku-Quej , Mircea Hidalgo-Mihart","doi":"10.14350/rig.52210","DOIUrl":"10.14350/rig.52210","url":null,"abstract":"<div><p>The Yucatan Peninsula is included as part of the initiative for the Mesoamerican Biological Corridor. In its central area, are located three Protected Natural Areas (PNA): the Biocultural Puuc Reserve (RBP, by its Spanish acronym), the Bala’an K’aax flora and fauna protected area (APB, by its Spanish acronym), Quintana Roo, and the Calakmul Biosphere Reserve (RBC, by its Spanish acronym), Campeche. The Puuc-Chenes region is located in the center of the Yucatan Peninsula - among these PNAs - which included important fragments of vegetation that in the past formed a continuum through the forests of the Yucatan Peninsula, constituting an important link to keep the connectivity of the Mayan forest. However, the expansion of the agricultural frontier is causing the fragmentation of the habitat. In the present study, the structural and functional connectivity of the Puuc-Chenes region is analyzed, based on habitat requirements of the Panthera onca (jaguar) by sex. Both, male and female, prefer tropical forest, however, <em>P. onca</em> males dare to transit in secondary vegetation and inclusively in agricultural areas. Males make inroads to villages more often than females, coming close to, and even crossing roads. P. onca males have a home range of 60 km<sup>2</sup>. In the present study, the ArcMap, FRAGSTATS and IDRISI software were used to analyses the structural and functional connectivity of the landscape, based on the known differences of habitat requirements for <em>P. onca</em> males and females. A vegetation and land use map of the studied area was elaborated, based on Landsat 7 ETM+ images, with 30 m size pixels. The following cover classes were differentiated: tropical forest, secondary forest, agriculture, urban, and water polls, which were validated in the fields. The Puuc-Chenes has an extension of 972 578 ha. Tropical forest was the dominant vegetation cover (49.8%) with the largest patch index covering 19.7% of the total landscape. The landscape had 2 509 fragments, from which 1 254 y 935 corresponded to secondary forest and anthropic patches, respectively. The contagion index was 62.5%, which indicates the existence oflarge and contiguous fragments. The total edge contrast index indicates the degree of landscape connectivity was 43.7%, meaning a medium contrast among the different class fragments. Likewise, forest had the highest area-weighted mean proximity index (PROX_AM de 8 701), confirming that the forest had bigger and less isolated fragments than the rest of the classes. The area of study, still have high value for the conservation of the habitat of the <em>P onca</em>. According to the results, we conclude that the Puuc-Chenes region has intermediate structural landscape connectivity, since a suitable corridor was identified for males and three corridors for both, males and females. Four priority fragments of forest were identified in the Puuc-Chenes landscape to be protected: the Puuc fragment with 1 916 km<sup>2</sup","PeriodicalId":39866,"journal":{"name":"Investigaciones Geograficas","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.14350/rig.52210","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130575111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J.A. Paz Tenorio , R. González Herrera , M. Gómez Ramírez , J.A. Velasco Herrera
The city of Tuxtla Gutiérrez, Chiapas, has historically presented processes landslides in the southern part of the valley, specifically in deposits of slope whose genesis is determined from La Mesa karst of Copoya, geological forms subjected to intense fracturing processes dissolution and erosion, giving as a result the breaking into large blocks. These are distributed in the margins of La Mesa being altered and destroyed by mechanical and chemical weathering, which generated smaller particles that rest on siltstones, shale and sandstones. This condition determines that the slopes are unstable by nature.
A 1000 x 1000 m grid was constructed, corresponding to the canvass of the Mercator Transverse Universal Coordinate System (UTM) of the topographic map scale 1:50 000 (INEGI, 1984;emsp Instituto, 2004, Lugo-Hubp, 1988). In each cell a centroid was generated to apply the interpolation process and draw isolines. For numerical variables such as drainage density and unevenness, defined ranges (number of equal intervals) were used by ArcMap software (version 9.3). For the non-quantitative variables such as geology, edaphology and soil use and vegetation, the same AHP method was used, obtaining numerical values for the cartographic representation.
In all three cases, the normalized values and a Consistency Index (CI) and Consistency Ratio (CR) (the latter according to the dimension of the matrix) were obtained, below 10%, so that the weights are correct.
In order to obtain information on the changes in the use of the ground, images of Google Earth of 2006, 2008 and 2010 were revised. Subsequently, a very high resolution orthophoto was added (pixel of 0.2 m), obtained for cadastral purposes by Town Hall of Tuxtla Gutierrez between the end of 2012 and the beginning of 2013.
Finally, five layers of information are defined, one for each variable, and the final result overlaps with the events recorded in the last nine years (2006 to date), which shows that the areas classified as Very High Threat are the more susceptible to the occurrence of these events. It is to be expected that in time, the incidence of this type of phenomena is manifested in the levels of High and Very High Threat.
Applying the Analytic Hierarchy Process (AHP) developed by Saaty (1988), which consists of matrix analysis and involves value judgments. In this way the matrix of preference over the selected criteria was generated, obtaining the weighting of the five chosen variables. It was important the knowledge of the study area, the documentation and local studies generated to date, where the criteria of the specialists are taken up.
The process was done in an Excel spreadsheet (2007 version), applying the corresponding formulas. Because only five variables and the size of the area (250 km2) were handled, no specialized software was required.
With the data obtained a table was created in
恰帕斯州的Tuxtla gutisamurez市在历史上曾在山谷的南部出现过滑坡过程，特别是在坡的沉积物中，其成因由Copoya的La Mesa喀斯特决定，地质形式受到强烈的压裂过程的影响，溶解和侵蚀，导致其破碎成大块。它们分布在拉梅萨边缘，在机械和化学风化作用下被改变和破坏，产生了更小的颗粒，这些颗粒落在粉砂岩、页岩和砂岩上。这种情况决定了边坡本质上是不稳定的。按照1:50 000比例尺的墨卡托横向通用坐标系(UTM)的标尺(INEGI, 1984;emsp Instituto, 2004; Lugo-Hubp, 1988)，构建了一个1000 x 1000 m的网格。在每个单元中生成一个质心来应用插值过程并绘制等值线。对于排水密度和不均匀度等数值变量，ArcMap软件(9.3版)使用定义范围(相等间隔的数量)。对于地质、地貌学、土壤利用和植被等非定量变量，采用相同的层次分析法，获得数值用于制图表示。在这三种情况下，得到的归一化值和一致性指数(CI)和一致性比率(CR)(后者根据矩阵的维数而定)均低于10%，因此权重正确。为了获取地表利用变化的信息，对2006年、2008年和2010年的Google Earth图像进行了修改。随后，Tuxtla Gutierrez市政厅在2012年底至2013年初期间获得了用于地籍目的的高分辨率正射影像(像素为0.2 m)。最后，定义了五层信息，每个变量一个，最终结果与过去9年(2006年至今)记录的事件重叠，这表明被归类为极高威胁的地区更容易发生这些事件。可以预期，随着时间的推移，这类现象的发生率将表现为“高威胁”和“非常高威胁”的级别。运用Saaty(1988)提出的层次分析法(AHP)，其中包括矩阵分析和价值判断。通过这种方式，生成了对选定标准的偏好矩阵，获得了五个选定变量的权重。重要的是研究领域的知识、迄今为止产生的文件和当地研究，在这些方面采用了专家的标准。这个过程是在一个Excel电子表格(2007版)中完成的，应用了相应的公式。因为只处理了5个变量和面积(250平方公里)，所以不需要专门的软件。根据获得的数据，创建了一个表，其中创建了名为“威胁”的列，该列对应于上述六个标准的参数之和。这反映在大规模清除过程的威胁地图中。因此，在其中极值包含在从0到1的范围内。采用多准则分析方法的启发组合方法，绘制了山体滑坡清除过程危害图，确定了城市区域的5个威胁等级，分别为极低5%、低27.1%、中39.3%、高15.3%和极高13.3%，其中极高的威胁等级主要分布在Copoya La Mesa周围的斜坡沉积物中，为最大危害等级。据估计，Tuxtla Gutierrez的人口约为62,500人(占总人口的11.6%)(市区537.102人)，他们居住在城市的南部和Copoya La Mesa两侧的30个农村城镇;估计约有28,000个住宅暴露在850个街区中。当前城市发展的趋势表明，管理和规范新建筑的必要性。虽然南坡是自然不稳定的，但北坡的住宅小区正在改变边坡的几何组合，这在中短期内可能是诱发滑坡发生的因素。
{"title":"Metodología para elaborar mapas de susceptibilidad a procesos de remoción en masa, análisis del caso ladera sur de Tuxtla Gutiérrez, Chiapas","authors":"J.A. Paz Tenorio , R. González Herrera , M. Gómez Ramírez , J.A. Velasco Herrera","doi":"10.14350/rig.52822","DOIUrl":"10.14350/rig.52822","url":null,"abstract":"<div><p>The city of Tuxtla Gutiérrez, Chiapas, has historically presented processes landslides in the southern part of the valley, specifically in deposits of slope whose genesis is determined from La Mesa karst of Copoya, geological forms subjected to intense fracturing processes dissolution and erosion, giving as a result the breaking into large blocks. These are distributed in the margins of La Mesa being altered and destroyed by mechanical and chemical weathering, which generated smaller particles that rest on siltstones, shale and sandstones. This condition determines that the slopes are unstable by nature.</p><p>A 1000 x 1000 m grid was constructed, corresponding to the canvass of the Mercator Transverse Universal Coordinate System (UTM) of the topographic map scale 1:50 000 (<span>INEGI, 1984</span>;emsp <span>Instituto, 2004</span>, <span>Lugo-Hubp, 1988</span>). In each cell a centroid was generated to apply the interpolation process and draw isolines. For numerical variables such as drainage density and unevenness, defined ranges (number of equal intervals) were used by ArcMap software (version 9.3). For the non-quantitative variables such as geology, edaphology and soil use and vegetation, the same AHP method was used, obtaining numerical values for the cartographic representation.</p><p>In all three cases, the normalized values and a Consistency Index (CI) and Consistency Ratio (CR) (the latter according to the dimension of the matrix) were obtained, below 10%, so that the weights are correct.</p><p>In order to obtain information on the changes in the use of the ground, images of Google Earth of 2006, 2008 and 2010 were revised. Subsequently, a very high resolution orthophoto was added (pixel of 0.2 m), obtained for cadastral purposes by Town Hall of Tuxtla Gutierrez between the end of 2012 and the beginning of 2013.</p><p>Finally, five layers of information are defined, one for each variable, and the final result overlaps with the events recorded in the last nine years (2006 to date), which shows that the areas classified as Very High Threat are the more susceptible to the occurrence of these events. It is to be expected that in time, the incidence of this type of phenomena is manifested in the levels of High and Very High Threat.</p><p>Applying the Analytic Hierarchy Process (AHP) developed by <span>Saaty (1988)</span>, which consists of matrix analysis and involves value judgments. In this way the matrix of preference over the selected criteria was generated, obtaining the weighting of the five chosen variables. It was important the knowledge of the study area, the documentation and local studies generated to date, where the criteria of the specialists are taken up.</p><p>The process was done in an Excel spreadsheet (2007 version), applying the corresponding formulas. Because only five variables and the size of the area (250 km2) were handled, no specialized software was required.</p><p>With the data obtained a table was created in","PeriodicalId":39866,"journal":{"name":"Investigaciones Geograficas","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.14350/rig.52822","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126462687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study area is located in the south-west coast of Araya in Sucre State, between 10° 33’30” N, 10°33’59” N y 64°15’32” W, 64°15’36” W, which it is affected by erosion processes impacting the population center that sits there. Hence the research is to analyze the geomorphological processes developed, based on a model no-experimental and design field, in descriptive and explanatory levels, operationalized in three phases: a) field, to collect 21 samples of surface sediment (0-20 cm) distributed in 12 samples in the first badlands and 9 samples in the second and lift the morphometry of these landforms erosion; (b) image analysis, three stages such as the development of thematic maps from the Topographical maps of Cumana, Geological Araya Peninsula and The Cadastral Charter covered: Punta Caracare; followed by drawing sketches of gullies, from the data collected in the field, refer to height, length and width of the land. Corresponding to the last two variables data were corrected by the equation suggested by Wolf and Ghilani (2008), for data collected on slopes using measuring tape; and finally drawing the sketch of the apical cliff line drawn from the interpretation of the captured images of Google Earth for the years 2003, 2006, 2009 and 2011, based on the proposal of Soriano (2009) and (c) laboratory, to analyze the comportamientode physical properties such as: hygroscopic water content, determined by gravimetric method, based on the arguments presented by Rivera, et al. (2006) and Toledo (2009); size distribution of the particles (Method Bouyoucos) following the protocol reported by Lara (1985); Percentage of dispersion and soil (double hydrometer method) based on the specifications referred by porters and Alva (1999). As for the chemical-mineralogical properties, it was determined from 10 samples analysis of total rocks and clay mineralogy, for both analyzes samples were prepared, processed and analyzed in the laboratory Diffraction x-ray (xrd), assigned to the Departmental Management Exploration pdvsa-intevep. Being used for analysis brand panalytical diffractometer X’Pert model equipped with a curved crystal monochromator graphite (Cu Ka radiation) and operated by the X-Pert Data collector ltupw3240 / 92 (version 2.2b) software, applying a range scanning of 5 ° θ 45 ° θ. For all rock and 0 2 ° to 35 ° θ clay minerals for less than 2 microns (<2μ) fraction. As to biochemical properties, the organic carbon were analyzed on the floor (COs) using in method Wlakley and Black, reported by Arrieche and Pacheco (sf) and Toledo (2008), and content of organic matter (mo) by the conventional factor Vammelen, referred to by Navarro (2007) and Toledo (2008) and checked against the proposal by palmaven (1992) qualitative scale In general, you have to cliff erosion affected by the retrograde type badlands, It consi
{"title":"Geomorfología y sedimentología del sistema de cárcavas en el borde costero al suroeste del Castillo de Araya, Estado Sucre, Venezuela","authors":"Franklin Antonio Nuñez Ravelo","doi":"10.14350/rig.53428","DOIUrl":"10.14350/rig.53428","url":null,"abstract":"<div><p>The study area is located in the south-west coast of Araya in Sucre State, between 10° 33’30” N, 10°33’59” N y 64°15’32” W, 64°15’36” W, which it is affected by erosion processes impacting the population center that sits there. Hence the research is to analyze the geomorphological processes developed, based on a model no-experimental and design field, in descriptive and explanatory levels, operationalized in three phases: a) field, to collect 21 samples of surface sediment (0-20 cm) distributed in 12 samples in the first badlands and 9 samples in the second and lift the morphometry of these landforms erosion; (b) image analysis, three stages such as the <em>development of thematic maps</em> from the Topographical maps of Cumana, Geological Araya Peninsula and The Cadastral Charter covered: Punta Caracare; <em>followed by drawing sketches of gullies</em>, from the data collected in the <span></span>field, refer to height, length and width of the land. Corresponding to the last two variables data were corrected by the equation suggested by Wolf and Ghilani (2008), for data collected on slopes using measuring tape; and finally <em>drawing the sketch of the apical cliff line drawn</em> from the interpretation of the captured images of Google Earth for the years 2003, 2006, 2009 and 2011, based on the proposal of Soriano (2009) and (c) laboratory, to analyze the comportamientode physical properties such as: hygroscopic water content, determined by gravimetric method, based on the arguments presented by Rivera, et al. (2006) and Toledo (2009); size distribution of the particles (Method Bouyoucos) following the protocol reported by Lara (1985); Percentage of dispersion and soil (double hydrometer method) based on the specifications referred by porters and Alva (1999). As for the chemical-mineralogical properties, it was determined from 10 samples analysis of total rocks and clay mineralogy, for both analyzes samples were prepared, processed and analyzed in the laboratory Diffraction x-ray (<span>xrd</span>), assigned to the Departmental Management Exploration <span>pdvsa-intevep</span>. Being used for analysis brand <span>pan</span>alytical diffractometer X’Pert model equipped with a curved crystal monochromator graphite (Cu Ka radiation) and operated by the X-Pert Data collector <span>ltu</span> <span>pw</span>3240 / 92 (version 2.2b) software, applying a range scanning of 5 ° θ 45 ° θ. For all rock and 0 2 ° to 35 ° θ clay minerals for less than 2 microns (<2μ) fraction. As to biochemical properties, the organic carbon were analyzed on the floor (COs) using in method Wlakley and Black, reported by Arrieche and Pacheco (sf) and Toledo (2008), and content of organic matter (<span>mo</span>) by the conventional factor Vammelen, referred to by Navarro (2007) and Toledo (2008) and checked against the proposal by <span>palmaven</span> (1992) qualitative scale In general, you have to cliff erosion affected by the retrograde type badlands, It consi","PeriodicalId":39866,"journal":{"name":"Investigaciones Geograficas","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.14350/rig.53428","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129073278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marcos Salas Pascual , Emilio Fernández Negrín , Gregorio Quintana Vega , Marcelino J. del Arco Aguilar
For the correct distribution of vegetation in an area, it is essential to manage accurate information on the variables that condition information. Most likely, the parameter that determines further the type of vegetation that can grow in one place is the amount of water available to plants. In this sense, and leaving aside the formations linked to watercourses, lakes, etc., the main source of this resource is the rain. Thus, the study of the distribution of vegetation in any territory is closely related to the analysis of rainfall it receives. To know the amount of rainwater that receives a zone always uses data provided by meteorological stations located in the same. The data collected by these stations are applied to a hypothetical, uniform and flat surface. This information is accurate enough when the scale at which it works is small (1: 100,000, 1: 50,000), but when it requires greater detail, especially in arid areas where the vegetation structure is open and the soil directly receives much of the rainfall, soil conditions exist that determine the distribution of rainwater and therefore access to this resource plants. Two of these variables, perhaps the most important are the inclination and the presence of rocky outcrops or stoniness on the floor.
In short, our job is to propose different mathematical models that allow to know the actual amount of water available to plants, we call A. This value is obtained from rainfall data (P), relating to the sloping terrain and the percentage of it occupied by rocks (af). The relationship between precipitation and tilt gives us a value we call the real precipitation (P’), which is lower the greater the inclination, since the amount of rainfall should be distributed over a larger area. The amount of rocky outcrop increases runoff, accumulating water in the earthy areas between the rocks, so a higher percentage of stoniness in soil involves an accumulation of water in the surrounding soil. Thus a model that allows both better explain the distribution of vegetation in arid areas and on large scales (: 25.000 or higher 1) is provided.
To test the model and test its usefulness, it has made a study of it in different localities in arid areas of the island of Gran Canaria, one of the Canary Islands. On this island 14 towns located in arid environments, with precipitation always less than 200 mm/m2 were chosen. Among these locations, with similar climatic conditions, there is a very important plant diversity. Most are occupied by a crasicaule very open scrub dominated by Euphorbia balsamífera, called tabaibal de tabaiba dulce, typical of the most barren areas of the Canary Islands, and considered the potential of its arid and hyper-arid vegetation areas. But other situations are occupied by a lush vegetation: the cardonal, almost totally enclosed high scrub, dominated by Euphorbia canariensis, the <
为了使一个地区的植被正确分布，必须对影响信息的变量的准确信息进行管理。最有可能的是，进一步决定在一个地方可以生长的植被类型的参数是植物可用的水量。从这个意义上说，撇开与水道、湖泊等有关的地层不谈，这种资源的主要来源是雨水。因此，对任何地区植被分布的研究都与对该地区所受降雨的分析密切相关。要知道接收一个区域的雨水量，通常使用位于该区域的气象站提供的数据。这些台站收集的数据应用于一个假设的均匀平坦的表面。当它的工作规模很小(1:10万，1:5万)时，这些信息是足够准确的，但是当它需要更详细的信息时，特别是在干旱地区，植被结构开放，土壤直接接收大部分降雨，土壤条件决定了雨水的分布，因此可以获得这种资源植物。其中两个变量，也许是最重要的是倾斜度和地表岩石露头或石质的存在。简而言之，我们的工作是提出不同的数学模型，让我们知道植物的实际可用水量，我们称之为a。这个值是从降雨数据(P)中获得的，与倾斜地形和岩石占地形的百分比(af)有关。降水和倾斜之间的关系为我们提供了一个我们称之为实际降水(P ')的值，倾角越大，该值越低，因为降雨量应该分布在更大的区域上。裸露的岩石增加了径流，在岩石之间的含土区域积累了水分，因此土壤中较高比例的石质涉及到周围土壤中的水分积累。因此，提供了一个既能更好地解释干旱地区植被分布，又能在大尺度(2.5万或更高)上解释植被分布的模型。为了测试该模型及其有效性，它在加那利群岛之一大加那利岛干旱地区的不同地区进行了研究。在这个岛上，选择了14个位于干旱环境中的城镇，降雨量总是小于200毫米/平方米。在这些气候条件相似的地点中，植物多样性非常重要。大部分被一种非常开放的灌木占据，主要是大戟balsamífera，称为tabaibal de tabaiba dulce，是加那利群岛最贫瘠地区的典型，被认为是干旱和超干旱植被地区的潜力。但其他地方则被郁郁葱葱的植被所占据:基本的，几乎完全封闭的高灌丛，以canariensis, cardón为主;甚至以树下灌木丛的存在为特征的地层，在那里不同的木本物种，如油橄榄、野生橄榄、刺柏。加那利松，杉木，甚至加那利岛松，加那利松。这些相同的植物构造在降雨量较高的地区似乎具有潜力，因此它们在这些干旱地区的存在应该与影响水资源分布的某些变量有关。对每一个地点的植物可用水量进行了计算，得到的结果符合所谓的矛盾，即在同一气候带找到不同类型的植被，具有不同的需水量。因此，在研究干旱地区植被分布的细节尺度时，所提出的模型提供了改进。可见，在研究任何地域的植被分布时，随着研究规模的缩小，所分析的参数的增加是必不可少的，特别是在分析干旱地区的植被情况时，植被的结构和降雨的季节性使得基质的特征对植被的存在方式有显著的影响。考虑到这些生态系统中水资源的稀缺性，任何影响植物水分可用性的方面都将对了解分布具有重要意义。
{"title":"Efecto de la inclinación y pedregosidad sobre el reparto del agua de lluvia, su cuantificación y aplicación al estudio de la vegetación en zonas áridas","authors":"Marcos Salas Pascual , Emilio Fernández Negrín , Gregorio Quintana Vega , Marcelino J. del Arco Aguilar","doi":"10.14350/rig.55204","DOIUrl":"10.14350/rig.55204","url":null,"abstract":"<div><p><span></span>For the correct distribution of vegetation in an area, it is essential to manage accurate information on the variables that condition information. Most likely, the parameter that determines further the type of vegetation that can grow in one place is the amount of water available to plants. In this sense, and leaving aside the formations linked to watercourses, lakes, etc., the main source of this resource is the rain. Thus, the study of the distribution of vegetation in any territory is closely related to the analysis of rainfall it receives. To know the amount of rainwater that receives a zone always uses data provided by meteorological stations located in the same. The data collected by these stations are applied to a hypothetical, uniform and flat surface. This information is accurate enough when the scale at which it works is small (1: 100,000, 1: 50,000), but when it requires greater detail, especially in arid areas where the vegetation structure is open and the soil directly receives much of the rainfall, soil conditions exist that determine the distribution of rainwater and therefore access to this resource plants. Two of these variables, perhaps the most important are the inclination and the presence of rocky outcrops or stoniness on the floor.</p><p>In short, our job is to propose different mathematical models that allow to know the actual amount of water available to plants, we call A. This value is obtained from rainfall data (<strong>P</strong>), relating to the sloping terrain and the percentage of it occupied by rocks (<strong>af</strong>). The relationship between precipitation and tilt gives us a value we call the real precipitation (<strong>P’</strong>), which is lower the greater the inclination, since the amount of rainfall should be distributed over a larger area. The amount of rocky outcrop increases runoff, accumulating water in the earthy areas between the rocks, so a higher percentage of stoniness in soil involves an accumulation of water in the surrounding soil. Thus a model that allows both better explain the distribution of vegetation in arid areas and on large scales (: 25.000 or higher 1) is provided.</p><p>To test the model and test its usefulness, it has made a study of it in different localities in arid areas of the island of Gran Canaria, one of the Canary Islands. On this island 14 towns located in arid environments, with precipitation always less than 200 mm/m<sup>2</sup> were chosen. Among these locations, with similar climatic conditions, there is a very important plant diversity. Most are occupied by a crasicaule very open scrub dominated by Euphorbia balsamífera, called <em>tabaibal de tabaiba dulce,</em> typical of the most barren areas of the Canary Islands, and considered the potential of its arid and hyper-arid vegetation areas. But other situations are occupied by a lush vegetation: the cardonal, almost totally enclosed high scrub, dominated by <em>Euphorbia canariensis</em>, the <","PeriodicalId":39866,"journal":{"name":"Investigaciones Geograficas","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.14350/rig.55204","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134549664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"","authors":"Gerónimo Barrera de la Torre","doi":"10.14350/rig.59439","DOIUrl":"https://doi.org/10.14350/rig.59439","url":null,"abstract":"","PeriodicalId":39866,"journal":{"name":"Investigaciones Geograficas","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.14350/rig.59439","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136612024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Trabajo de campo en el territorio de San Juan Lachao, Oaxaca. Un acercamiento desde las “otras” geografías al paisaje chatino","authors":"Gerónimo Barrera de la Torre","doi":"10.14350/rig.57877","DOIUrl":"https://doi.org/10.14350/rig.57877","url":null,"abstract":"","PeriodicalId":39866,"journal":{"name":"Investigaciones Geograficas","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.14350/rig.57877","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91778245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The morphological features of the relief and its quantitative morphometric quantification are essential elements in interpreting its influence on the hydrogeomorphological dynamics of watersheds in mountainous environments. This is particularly important when studying small spatial units (micro watersheds) and torrential regimes, as this influences the sudden and aggressive hydrological responses of these systems and the likelihood of activation of mass removal processes. In the study region (Vargas State, Venezuela) the most important debris flow recorded in Venezuela's history occurred on December 14, 15 and 16, 1999, as a consequence of extremely heavy rainfall in those dates associated with a very particular weather. For the above reasons, this research conducted a quantitative analysis of the relief features in watersheds of “El Ávila” massive northern hillside and their impact on the local hydrogeomorphological dynamics, aimed at identifying the main attributes influencing these dynamics. The study area is located in the northern-central region of Venezuela, in the central part of Vargas state, delimited by 10°32’25”-10°37’35”N and 66°40’08”- 66°59’12”W, and comprises thirteen micro watersheds of mountainous environment. The methodology consisted of (a) the geomorphological characterization of the area, from the review and interpretation of digitized base maps at scales 1:5 000 and 1:25 000, the digital elevation model (dem), aerial photographs at scale 1:5 000, orthophotomaps at scale 1:25 000, satellite images, Google Earth and Google Maps images, and geomorphological maps (landforms and geomorphological processes) at scale 1:25 000; (b) measurements and calculations of basic morphometric parameters of watershed relief on digital mapping using the ArcGIS 9.2 and their Spatial Analysis and ArcHydro modules, and the mathematical equations that define the other parameters using MS Excel; (c) descriptive statistical analysis (dsa) of morphometric parameters in Excel spreadsheets, based on the following statistics: maximum value, minimum value, mean, mode, median, variance, standard deviation, skewness, kurtosis, coefficient of variation, first quartile, second quartile and third quartile; (d) linear correlation analysis (lca) between morphometric parameters, based on the application and estimation of the Pearson product-moment correlation using the MS Excel xlstat add-on software; and (e) principal component analysis (pca) of morphometric parameters based on correlations, run with SPSS Statistics v. 17.0. The results show that the watersheds in the study area are conceived as exorheic hydrogeomorphological systems. Three relief units characteristic of these mountain environments systems were distinguished: catchment area, main drain channel and cone or alluvial fan, each with its own morphological features (landforms) and distinctive geomorphological processes. Landforms
{"title":"Análisis cuantitativo del relieve en cuencas de drenaje de la vertiente norte del macizo “El Ávila” (estado Vargas, Venezuela) y su significado hidrogeomorfológico","authors":"Williams José Méndez Mata","doi":"10.14350/rig.47722","DOIUrl":"https://doi.org/10.14350/rig.47722","url":null,"abstract":"<div><p>The morphological features of the relief and its quantitative morphometric quantification are essential elements in interpreting its influence on the hydrogeomorphological dynamics of watersheds in mountainous environments. This is particularly important when studying small spatial units (micro watersheds) and torrential regimes, as this influences the sudden and aggressive hydrological responses of these systems and the likelihood of activation of mass removal processes. In the study region (Vargas State, Venezuela) the most important debris flow recorded in Venezuela's history occurred on December 14, 15 and 16, 1999, as a consequence of extremely heavy rainfall in those dates associated with a very particular weather. For the above reasons, this research conducted a quantitative analysis of the relief features in watersheds of “El Ávila” massive northern hillside and their impact on the local hydrogeomorphological dynamics, aimed at identifying the main attributes influencing these dynamics. The study area is located in the northern-central region of Venezuela, in the central part of Vargas state, delimited by 10°32’25”-10°37’35”N and 66°40’08”- 66°59’12”W, and comprises thirteen micro watersheds of mountainous environment. The methodology consisted of (a) the geomorphological characterization of the area, from the review and interpretation of digitized base maps at scales 1:5 000 and 1:25 000, the digital elevation model (<span>dem</span>), aerial photographs at scale 1:5 000, orthophotomaps at scale 1:25 000, satellite images, Google Earth and Google Maps images, and geomorphological maps (landforms and geomorphological processes) at scale 1:25 000; (b) measurements and calculations of basic morphometric parameters of watershed relief on digital mapping using the ArcGIS 9.2 and their Spatial Analysis and ArcHydro modules, and the mathematical equations that define the other parameters using MS Excel; (c) descriptive statistical analysis (<span>dsa</span>) of morphometric parameters in Excel spreadsheets, based on the following statistics: maximum value, minimum value, mean, mode, median, variance, standard deviation, skewness, kurtosis, coefficient of variation, first quartile, second quartile and third quartile; (d) linear correlation analysis (<span>lca</span>) between morphometric parameters, based on the application and estimation of the Pearson product-moment correlation using the MS Excel <span>xlstat</span> add-on software; and (e) principal component analysis (<span>pca</span>) of morphometric parameters based on correlations, run with SPSS Statistics v. 17.0. The results show that the watersheds in the study area are conceived as exorheic hydrogeomorphological systems. Three relief units characteristic of these mountain environments systems were distinguished: catchment area, main drain channel and cone or alluvial fan, each with its own morphological features (landforms) and distinctive geomorphological processes. Landforms","PeriodicalId":39866,"journal":{"name":"Investigaciones Geograficas","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.14350/rig.47722","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90001808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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