Investigaciones Geográficas, Boletín del Instituto de Geografía,UNAM ISSN 0188-4611, Núm. 76, 2011, pp. 71-83 Erosion and marginalization in Pahuatlán municipality, Puebla: A binomial of causality? Received: 27 January 2010. Final version accepted: 30 May 2011. Rosalía Castelán Vega* Gladys Linares Fleites* Víctor Tamaríz Flores* Jesús Ruiz Careaga* Abstract. An understanding of the interaction between analysis and was confirmed by Pearson´s Chi-square test. deterioration of the environment and marginalization Erosion could be assigned to one of three grades: moderate, of communities is essential in order to formulate public severe and very severe. In the 32 towns that constitute the policies that will combine social and environmental ob- municipality, marginalization was moderate in 5, severe in jectives. The aim of the present study was to explore the 14 and very severe in 13. The correspondence analysis and relationship between erosion and marginalization in the mu- the Chi-square test showed a causal relationship between nicipality of Pahuatlán, Puebla, Mexico. The erosion was erosion and marginalization, although it was not possible assessed by the methods developed by FAO and Ruiz et al. to detect with certainty which is the cause and which the Marginalization was determined by the Consejo Nacional effect. However, the results can contribute to the design of de Población (CONAPO) method using Instituto Nacional de sustainable strategies for the municipality. Estadística, Geografía e Informática (INEGI) indicators. The relationship was established by a simple correspondence Key words: Erosion, marginalization, causality. Erosión y marginación en el municipio de Pahuatlán, Puebla: ¿Un binomio de causalidad? Resumen. Entender la interacción entre deterioro am- grados de erosión: moderada, fuerte y muy fuerte; de las 32 biental y marginación es esencial para formular políticas localidades que lo conforman, cinco presentan marginación públicas que combinen objetivos sociales y ambientales. media, 14 alta y 13 muy alta. El análisis de correspondencia Por lo que este trabajo tiene como objetivo contribuir al y la chi cuadrada muestran la relación entre las variables; establecimiento del vínculo entre erosión y marginación por lo que se concluye que existe relación de causalidad en el municipio de Pahuatlán, Puebla. La erosión se evaluó entre las variables erosión y marginación; no obstante, no según la metodología de la FAO y Ruiz y colaboradores; la es posible discernir de manera concreta cuál de ellas actúa marginación se determinó con la metodología del Consejo como causa y cuál resulta ser el efecto; sin embargo, los Nacional de Población (CONAPO) e indicadores del Instituto resultados sirven como herramienta objetiva para el diseño Nacional de Estadística, Geografía e Informática (INEGI). de estrategias sustentables del municipio. La relación se estableció con un análisis de correspondencia simple y se confirmó con la prueba chi cuadrada de Pearson. Palabras clave: Erosión, marginación, causalidad. Los resultados demuestran que el municipio presenta tres *Departamento de Investigación en Ciencias Agrícolas, Benemérita Universidad Autónoma de Puebla, 14 Sur 6301, Col. San Manuel, 72570, Puebla, Puebla, Mexico. E-mail: [email protected]; [email protected]; jtamariz@ siu.buap.mx; [email protected] bltn76_art_e.indd 71 08/11/2011 03:00:28 p.m. Rosalía Castelán Vega, Gladys Linares Fleites, Víctor Tamaríz Flores y Jesús Ruiz Careaga INTRODUCTION of the population who are indigenous peoples (INE- GI, 2005). Despite this situation, there have been Erosion is one of the most serious environmental no studies to test the causality of this relationship. problems at present confronting Mexico, above all Hence, the principal objective of the present study in the mountainous zones whose soils are particu- was to establish the relationship between various larly vulnerable and are transported by the runoff grades of erosion and the degrees of marginalization that affects various of their ecosystems (Maass, in this municipality. 1998; Becerra, 1999; Carabias, 2001; SEMARNAT, 2003). According to data supplied by the Ministry for the Environment and Natural Resources (SE- MATERIALS AND METHODS MARNAT, 2004), 64% of the country’s soils show signs of this process, with Puebla being the third Study area most affected State owing to its geographic position The municipality of Pahuatlán is in the north- and characteristics. Within the State, the municipa- western part of Puebla State (Figure 1), lying on a lity of Pahuatlán in the Sierra Norte is particularly small plain on the slopes of Ahila Hill, at 20°13’12” noteworthy for its severe erosion problems (Ruiz to 20°21’98” N, and 98°04’18” to 98°12’12” W. et al., 2001). Previous studies (Castelán, 2003 and It is bordered to the north by Tlacuilotepec and 2009) have shown that this process is favoured Hidalgo State, to the south by Naupan and Hidalgo by a combination of natural factors including the State, to the east by Naupan and Tlacuilotepec, and mountainous relief, the high rate of precipitation to the west by Honey and Hidalgo State. With an and the introduction of traditional crops such as area of 80.37 km2 it is the 140th largest municipa- maize and beans without conservation measures, lity of the State, and has 32 towns or villages orga- but also by the high marginalization of the popula- nized within ten local authorities (INEGI, 2000b). tion and the social and economic inequality in the It is part of the eastern Sierra Madre and belongs region, expressed by the inequitable distribution of to the subprovince of Carso Huasteco (Consejo land to the conspicuous disadvantage of the 49% de Recursos Minerales, 1995); a small area in the Figure 1. Pahuatlán municipality, Puebla. Pahuatlán Puebla México 72 ][ Investigaciones Geográficas, Boletín 76, 2011 bltn76_art_e.indd 72 08/11/2011 03:00:29 p.m. Erosion and marginalization in Pahuatlán municipality, Puebla: A binomial of causality? west has a temperate sub-humid climate with sum- of erosion, were designated ‘Reference Profiles’ and mer rains, but the bulk of the municipality has a were representative of the study area in terms of temperate humid climate with abundant summer soil. A detailed knowledge of their morphological rain; mean annual precipitation varies between characteristics allowed them to be compared with 1500 and 2000 mm. The dominant vegetation is the profiles of the sites described in order to identify mesophyll mountain pine-oak woodland. It is a the losses suffered. Erosion was then categorized zone of mountains and low ranges (Figure 2) with according to the following classification: none, pronounced gradients (Figure 3). The soils are light, moderate, severe and very severe. cambisols, calcisols and leptosols (Fuentes, 1972; INEGI, 2000b). Defining the marginalization At the same time as the soil sampling, there was Edaphic characteristics a direct survey of 288 rural workers selected ran- An edaphic survey established 31 sampling sites. domly in the 32 towns of the municipality. The description of the profiles, the setting and the The survey was designed so that the individual degree of erosion followed the methods of FAO responses could be compared by locality, and so (1980) and Ruiz et al. (1999); the best conserved that a database could be created (Azorín and profiles, i.e. those that have suffered the least effects Sánchez, 1996; PRECESAM, 2002). The activities Symbols Main river Tributary 580 - 884 m asl 884 - 1188 m asl 1188 - 1492 m asl 1492 - 1796 m asl 1796 - 2100 m asl Scale: 1: 250, 000 Digital elevation map of terrain of Pahuatlán, Puebla Produced by: Rosalía Castelán Vega Figure 2. Relief and height above sea level of the Pahuatlán municipality, Puebla. Investigaciones Geográficas, Boletín 76, 2011 ][ 73 bltn76_art_e.indd 73 08/11/2011 03:00:31 p.m. Rosalía Castelán Vega, Gladys Linares Fleites, Víctor Tamaríz Flores y Jesús Ruiz Careaga Symbols Main river Tributary 0 -18 18 -36 36 -54 54 -72 72 -90 Scale 1: 250, 000 Gradient map of Pahuatlán, Puebla Produced by: Rosalía Castelán Vega Figure 3. Gradient percentages in the Pahuatlán municipality, Puebla. undertaken in the plots and/or units of production RESULTS were identified in terms of deforestation, produc- tive systems, agricultural practices and backyard Edaphic characteristics practices, socio-economic status and the various The municipality includes various sectors with means of earning income (León, 2002). moderate, severe or very severe degrees of erosion, The information generated was analysed and as follows (Figure 4). compared with indicators supplied by INEGI Sectors with moderate erosion. These lie (2000a) and CONAPO (2001). Marginalization in within the north-western, western and eastern parts the 32 towns was then classified according to the of the municipality and are characterized by mar- following grades: low, medium, high and very high ked gradients that constitute a potential risk factor (CONAPO, 2001). for erosion, since the gradients are about 25%. The vegetation is remains of pine-oak woodland with Relationship between the degrees of erosion signs of secondary growth; years ago, an intense and marginalization deforestation favoured the loss of a great quantity Finally, the information collected was subjected to of soil, so that there is still moderate erosion in a simple correspondence analysis and a Pearson’s these sectors. However, the period of exploitation Chi-square test in the MINITAB 15 (Linares, 2006) to