Gerardo Bocco

Predicting land-cover and land-use change in the urban fringe A case in Morelia city, Mexico

Land-cover and land-use (LCLU) change was quantified for the last 35 years within and in the vicinity of a fast growing city in Mexico, using rectified aerial photographs and geographic information systems (GIS). LCLU change was projected for the next 20 years using Markov chains and regression analyses. The study explored the relationships between urban growth and landscape change, and between urban growth and population growth. The analysis of Markov matrices suggests that the highest LCLU attractor is the city of Morelia, followed by plantations and croplands. Grasslands and shrublands are the least stable categories. The most powerful use of the Markov transition matrices seems to be at the descriptive rather than the predictive level. Linear regression between urban and population growth offered a more robust prediction of urban growth in Morelia. Hence, we suggest that linear regression should be used when projecting growth tendencies of cities in regions with similar characteristics.

Remote sensing and GIS-based regional geomorphological mapping—a tool for land use planning in developing countries

Abstract Land use planning and necessary supporting data are crucial to developing countries that are usually under severe environmental and demographic strains. Approaches and methods to map the variability of natural resources are important tools to properly guide spatial planning. In this paper, we describe a method to quickly map terrain at reconnaissance (1:250,000) and semi-detailed (1:50,000) levels. This method can be utilized as a basis for further land evaluation and land use planning in large territories. The approach was tested in the state of Michoacan, central-western Mexico, currently undergoing rapid deforestation and subsequent land degradation. Results at the reconnaissance level describe the geographic distribution of major landforms and dominant land cover, and provide a synoptic inventory of natural resources. Results at the semi-detailed level indicate how to nest individual landforms to major units and how they can be used to run procedures for land evaluation. If combined with appropriate socioeconomic data, governmental guidelines for land use planning can be formulated on the basis of reconnaissance and semi-detailed terrain analysis.

Land use-cover change processes in highly biodiverse areas: the case of Oaxaca, Mexico

Abstract Land use-cover changes (LUCC) such as deforestation, have resulted as global warming and a reduction of environmental services, with large negative consequences for mankind. Effects based on statistics alone have not been sufficient enough to detect, stop and eventually revert negative LUCC processes that are strongly related to biodiversity loss. It is, therefore, of prime concern to assess and depict cartographically, major LUCC processes simultaneously. Mexico harbors a large pool of biodiversity, mostly restricted to a few locations among which, The State of Oaxaca plays a major role. In this state, nevertheless, drastic negative LUCC processes are taking place. Land cover types, mapped in previous surveys, overlaid on recent Landsat imagery and 300 ground truth sites, were used to detect current LUCC. Rates of conversion of the most important LUCC processes were computed and mapped simultaneously. Oaxaca has lost over half a million hectares of forested areas during the last 20 years. The core results may contribute to the understanding of how LUCC and GIS methods can provide better and more targeted information that may help to improve conservation policies and land use planning strategies.

SOLID WASTE MANAGEMENT IN MUNICIPALITIES IN MEXICO: GOALS AND PERSPECTIVES

Mexico is faced with serious environmental and administrative challenges with respect to solid waste (SW) management. Just as in other developing countries, the public sanitation system lacks because of inadequate planning, as well as unsustainable SW management. The country is experiencing an urbanization process in which approximately 70% of the population are concentrated in its ten largest cities; the rest are spread throughout 200 000 towns in Mexicos 2 000 000 km2. This has caused a change in the populations consumption patterns, which has resulted in a more heterogeneous composition of SW and an increase in its generation rate. The current situation of the SW management systems in Mexico is analyzed, and the environmental, technical, administrative, economic and social goals with which Mexicos public sanitation systems face, are discussed. The principal goal facing these public sanitation systems is the development of adequate disposal of SW, since the municipalities find themselves unable to administer sanitary landfills according to Mexican legislation because they lack financial means and the technical and human infrastructure. SW collection in Mexico depends heavily on personnel with no technical training and the separation of the waste is carried out by an ever-increasing number of scavengers. The importance of including these groups in the decision-making process in order to assure the success of SW management programs is presented, along with the need to create interdisciplinary work groups that could collaborate in driving forward the agenda.

Gully erosion: processes and models

Confusing and sometimes contradictory results and reports have led to a sizeable body of literature on, but unfortunately not to a clear understanding of, gully erosion processes. In the following review, relevant concepts on gully erosion are summarized. Their implications for gully erosion modelling are presented along with some recommendations for future research.

Neotropical Forest Conservation, Agricultural Intensification, and Rural Out-migration: The Mexican Experience

Forest loss in the tropics is one of the most critical contemporary environmental problems. Understanding the complex sociopolitical and ecological forces operative in producing this problem has thus become an important scientific mandate. Some recent literature has suggested that modern market economy trends in Latin America—namely, rural out-migration and policies strongly favoring high-input, industry-based agriculture—have helped curtail and sometimes revert the net loss of tropical forests, mainly through afforestation of land abandoned by smallholders. Government in Mexico, a megadiverse country with one of the biggest out-migration and remittance economies in the world, has excelled in applying free-market policies and in discouraging historical smallholder agriculture. Our analysis of Mexicos development path and of recent deforestation and reforestation trends at the national, regional, and local levels shows that, contrary to expectations, net deforestation is still occurring, and that other development, agricultural, and reforestation strategies are needed.

Urban solid waste generation and disposal in Mexico: a case study

The adequate management of municipal solid waste in developing countries is difficult because of the scarcity of studies about their composition. This paper analyses the composition of urban solid waste (USW) in the city of Morelia, Michoacán, Mexico. Residential and non-residential waste sources were sampled, and a structured interview was made to evaluate the socioeconomic characteristics of the studied area. Also, to determine the seasonal patterns of solid waste generation and the efficiency level of the collection service, quantification of solid waste deposited in the dumping ground was measured. Our results show that the recorded amount of SW deposited in the municipal dumping-ground is less than the estimated amount of SW generated; for this reason, the former amount is not recommended as an unbiased indicator for planning public waste collection services. It is essential that dumping-grounds are permanently monitored and that the incoming waste be weighed in order to have a more efficient record of USW deposited in the dumping-ground per day; these data are fundamental for developing adequate managing strategies.

Forecasting Generation of Urban Solid Waste in Developing Countries—A Case Study in Mexico

ABSTRACT Based on a study of the composition of urban solid waste (USW) and of socioeconomic variables in Morelia, Mexico, generation rates were estimated. In addition, the generation of residential solid waste (RSW) and nonresidential solid waste (NRSW) was forecasted by means of a multiple linear regression (MLR) analysis. For residential sources, the independent variables analyzed were monthly wages, persons per dwelling, age, and educational level of the heads of the household. For nonresidential sources, variables analyzed were number of employees, area of facilities, number of working days, and working hours per day. The forecasted values for residential waste were similar to those observed. This approach may be applied to areas in which available data are scarce, and in which there is an urgent need for the planning of adequate management of USW.

THE USE OF ECOLOGICAL SCIENCE BY RURAL PRODUCERS: A CASE STUDY IN MEXICO

The role of ecological science in promoting sound environmental decisions has concerned ecologists worldwide and it has been stressed that the application of eco- logical knowledge requires new interactive and participatory forms of research, as well as sound partnerships between ecologists and land managers. However, concrete examples of ecological science as part of rural decision making have rarely been examined, especially in intertropical countries. We analyzed interactions between ecological scientists from the National Autonomous University of Mexico (UNAM) and a rural indigenous community involved in forest management in Central-Western Mexico. Using qualitative research meth- ods (such as observing participants, conducting interviews; generally focusing on the mean- ings that social actors give to phenomena), we compared the perspectives of the academic and community sectors in relation to benefits, products, problems, and obstacles faced when conducting integrative forest management. The research showed the relevance of rural communities demanding scientific information for ecosystem management and of academic institutions accepting to respond to these demands. Participatory approaches and continuous communication between sectors were essential for establishing trust and commitment for everyone involved. The obstacles found were related to an academic institutions inability to support such an experience and to accept capacity building of rural managers as part of its scientific mission. We concluded that applied ecological science in developing countries, such as Mexico, should regard rural communities as key ecosystem managers and should respond to their needs and demands in order to convert pure scientific findings into wise environmental decisions.

Classification of sources of municipal solid wastes in developing countries

Abstract The existence of different classifications of municipal solid waste (MSW) creates confusion and makes it difficult to interpret and compare the results of generation analyses. In this paper, MSW is conceptualized as the solid waste generated within the territorial limits of a municipality, independently of its source of generation. Grounded on this assumption, and based on the economic activity that generates a solid waste with determinate physical and chemical characteristics, a hierarchical source classification of MSW is suggested. Thus, a connection between the source and the type of waste is established. The classification categorizes the sources into three divisions and seven classes of sources: residential, commercial, institutional, construction/demolition, agricultural–animal husbandry, industrial, and special. When applied at different geographical scales, this classification enables the assessment of the volume of MSW generated, and provides an overview of the types of residues expected to be generated in a municipality, region or state.