Diversity-Productivity Relationship in the Northeastern Tamaulipan Thornscrub Forest of Mexico

This research examines the diversity-productivity relationship in a semiarid scrubland, initially under late successional conditions and subsequently under early successional conditions created by experimental clearing, to explore the roles that productivity and stochastic mortality play in species exclusion in this environment. A total of fifteen plots were studied by measuring environmental conditions and biomass components of shrubs and seedlings. These stands were distributed along a productivity gradient across five different landforms. A hypothesis about the stochastic self-thinning mortality model along the gradient was evaluated with the diversity-productivity-environment data. The diversity-productivity relationship was linear and reversed between the early and late succession stages. The hypothesis of stochastic mortality of species exclusion was rejected in the early stages of succession and partially accepted in the mature stage of succession. Species exclusion was negatively related to productivity gradients, suggesting that strong interspecific competition occurs in high productivity plots and that a larger number of species can survive in higher abiotic stress landscapes. Further research is needed to understand the temporal and spatial variations of the ecological interactions that shape this plant community

Use of the Analytic Hierarchy Process in Forest Budget Allocation in Durango, Mexico

From the Proceedings of the 2004 Meetings of the Hydrology Section - Arizona-Nevada Academy of Science - April 12, 2004, Midwestern University, Glendale, ArizonaThis article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]

Multiobjective Forest Management in San Miguel, Mexico

From the Proceedings of the 2002 Meetings of the Hydrology Section - Arizona-Nevada Academy of Science - April 6, 2002, Midwestern University, Glendale, ArizonaThis article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]

A Spatial and Temporal Multiobjective Forest Management Analysis in Ejidos of Durango, Mexico

From the Proceedings of the 2006 Meetings of the Hydrology Section - Arizona-Nevada Academy of Science - April 8, 2006, University of Arizona, TucsonThis article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]

The effect of payments for ecosystem services on forest cover, land use, and capacity building in northern Mexico

The endorreic watershed of Laguna de Santiaguillo, located in Durango, Mexico, provides important ecosystem services to local communities. Due to its size and forest diversity, it is the refuge for many reptiles and migratory birds. It captures a large amount of carbon dioxide in its soil and vegetation, all while catching the water that will then be used for agriculture and aquifer recharge. To improve these ecosystem services, as well as maintain a collaborative relationship with the watershed, several community-owned properties in this area, known as ejidos, enrolled in a federally supported Payments for Ecosystem Services (PES) program. This program grants economic subsidies to landowners to help protect forest resources. However, there is little information on the effect that this program has on these types of community-owned properties. Through a spatial analysis, the vegetation index was estimated, as well as the impact that this program has had on the communities and their resources. A Difference-in-Differences (DiD) method was used to test for differences in remotely sensed vegetation cover and land use between PES and non-PES ejido recipients. Socioeconomic indicators, obtained from surveys, were also evaluated. Results show that changes in vegetation cover and land use were significant in secondary forests but not in primary forests in the selected periods. The overall difference, given by the DiD model, show no significant differences in land use changes. This study can help resource managers to monitor the additionality on forest resources and internal organization of ejido participants

Bioenergy from Woody Biomass, Potential for Economic Development, and the Need for Extension

This article reviews the economic impacts of woody biomass utilization for bioenergy development and the role of Extension. Woody biomass is an alternative to reduce foreign oil dependency and mitigate greenhouse emissions. It is renewable, abundant, and can be virtually produced everywhere. Studies suggest that recovery of woody biomass, construction, and operation of biofuels or biopower facilities are a reliable source of employment generation and bring additional income to local communities. Extension should focus on the analysis of areas with the greater potential (e.g., feedstock, infrastructure, and labor availability) to promote sustainable woody biomass utilization

Evaluating the Multi-Functionality of Forest Ecosystems in Northern Mexico

Managing multiple ecosystem services is a complex task that involves special interactions among different resources, services, and stakeholders. Mexican forests have been traditionally managed for the single purpose of obtaining wood, benefiting a small sector of society. In this study, we evaluated the interactions among various ecosystem services, namely carbon content, tree diversity, surface water runoff, and the net present value of timber production. We also attempted to determine the most suitable basal area level that best satisfies the management of these services combined. Bivariate correlations, non-linear regression models, and a multiobjective decision-making technique are used to analyze the data in the study. Results indicate that trade-offs exist between surface water runoff and tree basal area. A synergistic relationship, between net present value and carbon content with basal area, was also observed. Tree diversity has a synergistic relationship with basal area in open forests, but a trade-off relationship in denser forests. The most preferred forest management level that satisfies the desired ecosystem services is between 17 and 21 m2/ha of residual basal area. We hope that adopting this multiobjective study can cement collaborative strategies among Mexican resource managers, landowners, environmental groups, and others interested in forest management

Effects of stand variables on stemflow and surface runoff in pine-oak forests in northern Mexico.

The flow of water in temperate forests depends on the amount of precipitation, type of soil, topographic features, and forest cover, among other factors. Unlike the first three, forest cover can be modified by silvicultural treatments, the effects of which manifest in the quality and quantity of water, as well as in the transport of sediments and soil nutrients. The objective of this study was to analyze the effect of some stand variables on surface runoff and stemflow in pine-oak forests of northern Mexico. The stand variables included tree diameter at breast height, basal area, canopy cover, and volume. They were collected in eight 0.1-ha circular plots, measured in 2016 and re-measured in 2018. Nonlinear quantile regression was used to determine the best-fit relationships between the variables. Results indicated that surface runoff was most closely and inversely related to basal area. Stemflow was related to diameter at breast height, while showing no statistical significance. A stemflow funneling ratio did show an inverse, statistically-significant relationship with diameter at breast height. These results can help determine best forest management regimes compatible with the quantity and quality of water fluxes in this type of ecosystem

Effect of forest management on tree diversity in temperate ecosystem forests in northern Mexico.

An important challenge for silvicultural practices is the conservation of tree diversity while fulfilling the traditional objectives of forest management, most notably timber harvesting. The purpose of this study was to compare the tree diversity before and after the application of silvicultural treatments in a temperate forest in northern Mexico. Fifteen experimental plots, each measuring 2500 m2, were established to evaluate the immediate effect of four silvicultural treatments. These treatments were identified by their levels of management: intensive (clearcut, removal 100%), semi-intensive (removal of 59-61% of basal area), conservative (removal of 29-31% of basal area), and a control group. New forest guidelines, in contrast to conventional approaches, were applied to the semi-intensive and conservative treatments based on health and diversity conditions. Basal area, canopy cover, tree and total volume were measured in each plot. The Importance Value Index, alpha diversity, and evenness were estimated before and after treatments. Eighteen species belonging to five genera and five families were found in the study area. The species with the highest ecological values were Pinus durangensis, P. teocote, Quercus sideroxyla, and Quercus convallata with IVI numbers between 13.6 and 24.5%. Alpha diversity was intermediate (Margalef: 2.9 to 3.8), while dominance and evenness were above average compared to other studies (Simpson: 0.69 to 0.77; Shannon-Wiener: 1.44 to 1.6; Pielou: 0.76 to 0.85). The species evenness index in the conservative treatment was high (Sorensen, Jaccard, quantitative Sorensen and Morisita-Horn; 88 to 99%), although abundance decreased. Overall, there were no significant differences in IVI values and diversity indicators before and after treatments, with the exception of the clearcut treatment. When associating the diversity indices with stand variables, only the Pielou's evenness index showed a significant relationship between them. We concluded that both the conservative and semi-intensive treatments did not generate significant changes in tree diversity, but the former had slightly higher alpha diversity indices. These results can provide a better insight on silvicultural practices and their effects on species composition