Value of Small Patches in the Conservation of Plant-Species Diversity in Highly Fragmented Rainforest

Abstract:  We evaluated the importance of small (<5 ha) forest patches for the conservation of regional plant diversity in the tropical rainforest of Los Tuxtlas, Mexico. We analyzed the density of plant species (number of species per 0.1 ha) in 45 forest patches of different sizes (1–700 ha) in 3 landscapes with different deforestation levels (4, 11, and 24% forest cover). Most of the 364 species sampled (360 species, 99%) were native to the region, and only 4 (1%) were human-introduced species. Species density in the smallest patches was high and variable; the highest (84 species) and lowest (23 species) number of species were recorded in patches of up to 1.8 ha. Despite the small size of these patches, they contained diverse communities of native plants, including endangered and economically important species. The relationship between species density and area was significantly different among the landscapes, with a significant positive slope only in the landscape with the highest deforestation level. This indicates that species density in a patch of a given size may vary among landscapes that have different deforestation levels. Therefore, the conservation value of a patch depends on the total forest cover remaining in the landscape. Our findings revealed, however, that a great portion of regional plant diversity was located in very small forest patches (<5 ha), most of the species were restricted to only a few patches (41% of the species sampled were distributed in only 1–2 patches, and almost 70% were distributed in 5 patches) and each landscape conserved a unique plant assemblage. The conservation and restoration of small patches is therefore necessary to effectively preserve the plant diversity of this strongly deforested and unique Neotropical region.     

Identifying Potential Impact of Lead Contamination Using a Geographic Information System

/ The main objective of this research was to identify the potential hazards associated with lead contami-nation from fixed sources in the city of Tijuana. An exploratory model is presented that describes the potential polluting sources as well as the exposed universe. The results of the analysis provide a clear picture of the geographic distribution of hazards areas for potential lead pollution in Tijuana. The findings are indicative of the dramatic consequences of rapid industrialization and urbanization in a city where there have not been significant planning efforts to mitigate the negative effects of this growth. The approach followed helps to narrow the universe of potential pollution sources, which can help to direct attention, research priorities, and resources to the most critical areas.KEY WORDS: Lead contamination; Industrial hazards; GIS; Tijuana; Mexico     

Potential Ecological Distribution of Alien Invasive Species and Risk Assessment: a Case Study of Buffel Grass in Arid Regions of Mexico

Abstract:  Alien invasive species represent a severe risk to biodiversity. Such is the case of buffel grass ( Cenchrus ciliaris L.), a native species of Southern Asia and East Africa, which was introduced to the United States and Mexico for use in improved pasture. Here we present a coarse-grain approach to determine areas where buffel grass can potentially invade in Mexico. Potential species distributions, suitable for an invasion by buffel grass, were obtained through genetic algorithms. We generated the algorithms with databases of herbaria specimens; environmental digital covers of climate, soil texture, and vegetation; and the program called Genetic Algorithm for Rule-Set Prediction. This spatial modeling approach was validated with a case study for the state of Sonora, Mexico, where the occurrence of buffel grass has been proven. The most threatened vegetation types for the specific case of Sonora were desert scrub, mesquite woodlands, and tropical deciduous forest. The model prediction agreed with the field observations recorded in Sonora and allowed us to apply the same procedure to produce a map of the potential sites of buffel grass invasion for Mexico. The areas at risk of invasion mostly occurred in desert scrub, located in the arid and semiarid regions of northern Mexico. This methodology provides an initial baseline for assessment, prevention, and management of alien species that may become invasive under certain environmental conditions. Additionally this modeling approach provides a tool for policy makers to use in making decisions on land-use management practices when alien species are involved.     

Disturbance-Response Analysis: a Method for Rapid Assessment of the Threat to Species in Disturbed Areas

Abstract:  We developed a method with which to analyze a specie's response to chronic anthropogenic disturbance (CAD). We regressed density of individuals on the intensity of 3 disturbance agents (human activities, raising livestock, and land degradation) along CAD gradients to determine how much CAD is experienced by a species; whether species are ruderal (achieving maximum densities in disturbed sites); whether density declines as a result of CAD; which disturbance agents are responsible for this reduction; and the number of populations that decline as a result of CAD. We tested the method on 9 threatened Mammillaria species (Cactaceae). Seven species were ruderal. In 4 species, actual disturbance surpassed the CAD intensity in which plants achieved their maximum densities; thus, the density of those 4 species appeared to be declining. For 7 species, some populations were threatened by human activities or livestock, whereas others were favored by them. Land degradation negatively affected all species. Our results allowed us to distinguish 4 groups of species that had similar responses and thus may require different forms of management. Our method provided an estimation of the growth rate (λ) of the studied populations that was significantly correlated with λs obtained from demographic studies. The size structures of populations were consistent with the predictions of the analysis, which suggests our results are consistent and reliable. Disturbance–response analysis provides a basis for management in heavily populated areas, where conservation must be achieved along with development activities that cause CAD. The method provides readily interpretable information, which facilitates participative decision making; the data are rapidly generated, which makes it appropriate when results are required promptly or for assessment of large numbers of species; and it provides a comprehensive perception of how threatened species behave in the real world.     

Life cycle assessment for printed newspapers in Northwestern Mexico

This paper aims to present the relevant results of a Life Cycle Assessment (LCA) study conducted on printed matter under a sheet-fed offset printing process by a company located in northwestern Mexico. Different scenarios were simulated in order to support decisions related to the improvement of environmental performance along the production processes. The study design was based on the European Platform on Life Cycle Assessment (EPLCA), which is in line with the ISO 14040 and 14044:2006 standards on LCA. The scope of the study was cradle-to-gate, with emphasis on the production of printed matter. The method chosen for the impact assessment was Impact 2002+ with a combined midpoint–damage approach. The results of the study showed that the major contributors to adverse effects were, primarily electricity consumption followed by paper consumption during the printing operation, as well as consumption of ink to a small degree. As for the plate-making operation along with the generation of secondary products, the result was negative. This is essentially due to involvement of recyclable materials, thus contributing to the prevention of raw material extraction. The smallest impact was observed from processes involving cleaning products and LP gas. The main issues of concern stemming from the results are electricity consumption and printing – both activities dominate almost all the midpoint categories. Generation of secondary products also had a relative environmental impact along the supply chain. Cleaning agents and LP gas did not have a significant impact on the final results of the process.     

New ‘renewable’ frontiers: contested palm oil plantations and wind energy projects in Brazil and Mexico

ABSTRACT

This paper argues that new land conflict frontiers are emerging in the context of renewable energy production. The novel aspect of these frontiers is a ‘green’ framing of the use of land considered ‘degraded’, expressing it as a climate protection strategy, and consequently causing similar dynamics of conflict in different regions. With reference to political ecology debates on the notion of frontiers, we analyze the social conflicts over palm oil production for biodiesel and wind energy development in Brazil and Mexico, respectively. We show that green narratives, understood as forms of knowledge production concerning the protection of the climate and sustainable development, not only represent legitimization strategies for new land grabs, but also come with their own dynamics of social conflict and their own constellations of actors.     

Building Consensus in Environmental Impact Assessment Through Multicriteria Modeling and Sensitivity Analysis

Multicriteria decision analysis (MCDA) increasingly is being applied in environmental impact assessment (EIA). In this article, two MCDA techniques, stochastic analytic hierarchy process and compromise programming, are combined to ascertain the environmental impacts of and to rank two alternative sites for Mexico City’s new airport. Extensive sensitivity analyses were performed to determine the probability of changes in rank ordering given uncertainty in the hierarchy structure, decision criteria weights, and decision criteria performances. Results demonstrate that sensitivity analysis is fundamental for attaining consensus among members of interdisciplinary teams and for settling debates in controversial projects. It was concluded that sensitivity analysis is critical for achieving a transparent and technically defensible MCDA implementation in controversial EIA.     

Dutch disease and policy adjustments to the oil boom: A comparative study of Indonesia and Mexico

Dutch disease and, more recently, resource curse thesis have been critical issues for development of resource abundant economies. This paper attempts a comparison between Indonesia and Mexico in their policy adjustments to the oil boom with special reference to the Dutch disease. There exists a striking contrast, especially in their fiscal, foreign borrowing, and exchange rate policies, and confirms the conventional understanding that a booming government should be conservative, as was the case in Indonesia, in its macroeconomic management to avoid the Dutch disease. Equally significant, investment use of oil revenues to strengthen the tradable sector is another factor responsible for Indonesian success. Mexico provides a clear-cut example of the resource curse thesis, but Indonesia is an exception.     

Sustainable Land Use Requires Attention to Ecological Signals

This case study details the difficulties of landscape management, highlighting the challenges inherent in managing natural resources when multiple agencies are involved, when the land users have no incentive for conservation, and when government agencies have too few resources for effective management. Pumping of groundwater from the aquifer of La Costa de Hermosillo in the state of Sonora, Mexico, began in 1945 and developed so quickly that by the late 1950s salinity intrusion from the Gulf of California was occurring in the wells. In the 1970s, the irrigatable land in La Costa peaked at 132,516 ha and the extracted volume of water from the aquifer peaked at around 1.14 billion cubic meters annually. By the 1980s, 105 wells of the total of 498 were contaminated with seawater and, therefore, identified for closure. At present La Costa de Hermosillo still represents 15% of the total harvested land, 16% of the total annual production, and 23% of the gross agricultural production of the state of Sonora. However, there are approximately 80,000 ha of abandoned fields due to salt water intension, lack of water and/or lack of credit available to individual farmers. This unstable situation resulted from the interplay of water management policies and practices, and farm-land policies and practices. While government agencies have been able to enforce better water use for agricultural production, there remains a significant area that requires restoration from its degraded state. For this piece of the ecosystem management puzzle, government agencies have thus far been unable to affect a solution.     

Socio-economic vulnerability to climate change in the central mountainous region of eastern Mexico

Climate change effects are expected to be more severe for some segments of society than others. In Mexico, climate variability associated with climate change has important socio-economic and environmental impacts. From the central mountainous region of eastern Veracruz, Mexico, we analyzed data of total annual precipitation and mean annual temperature from 26 meteorological stations (1922–2008) and from General Circulation Models. We developed climate change scenarios based on the observed trends with projections to 2025, 2050, 2075, and 2100, finding considerable local climate changes with reductions in precipitation of over 700 mm and increases in temperature of ~9°C for the year 2100. Deforested areas located at windward were considered more vulnerable, representing potential risk for natural environments, local communities, and the main crops cultivated (sugarcane, coffee, and corn). Socio-economic vulnerability is exacerbated in areas where temperature increases and precipitation decreases.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0690-4) contains supplementary material, which is available to authorized users.