Balvanera, P., T. M. Daw, T. Gardner, B. Martín-López, A. Norström, C. Ifejika Speranza, M. Spierenburg, E. M. Bennett, M. Farfan, M. Hamann, J. N. Kittinger, T. Luthe, M. Maass, G. D. Peterson, and G. Pérez-Verdin. 2017. Key features for more successful place-based sustainability research on social-ecological systems: a Programme on Ecosystem Change and Society (PECS) perspective. Ecology and Society 22(1):14. https://doi.org/10.5751/ES-08826-220114

Biological diversity can be defined as variability among living organisms from all sources, including terrestrial organisms, marine and other aquatic ecosystems, and the ecological complexes which they are part of. This includes diversity within species, between species, and of ecosystems. Numerous diversity indices combine richness and evenness in a single expression, and several climate-based explanations have been proposed to explain broad-scale diversity patterns. However, climate-based water-energy dynamics appears to be an essential factor that determines patterns of diversity. The Mexican Sierra Madre Occidental occupies an area of about 29 million hectares and is located between the Neotropical and Holarctic ecozones. It shelters a high diversity of flora, including 24 different species of Pinus (ca. 22% on the whole), 54 species of Quercus (ca. 9–14%), 7 species of Arbutus (ca. 50%) and many other trees species. The objectives of this study were to model how tree species diversity is related to climatic and geographic factors and stand density and to test the Metabolic Theory, Productivity-Diversity Hypothesis, Physiological Tolerance Hypothesis, Mid-Domain Effect, and the Water-Energy Dynamic Theory on the Sierra Madre Occidental, Durango. The results supported the Productivity-Diversity Hypothesis, Physiological Tolerance Hypothesis and Water-Energy Dynamic Theory, but not the Mid-Domain Effect or Metabolic Theory. The annual aridity index was the variable most closely related to the diversity indices analyzed. Contemporary climate was found to have moderate to strong effects on the minimum, median and maximum tree species diversity. Because water-energy dynamics provided a satisfactory explanation for the patterns of minimum, median and maximum diversity, an understanding of this factor is critical to future biodiversity research. Quantile regression of the data showed that the three diversity parameters of tree species are generally higher in cold, humid temperate climates than in dry, hot climates.

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.

Un elemento clave para favorecer un manejo forestal sustentable es conocer las compensaciones, sinergias y relaciones de los servicios ecosistémicos generados por los bosques. Este estudio tuvo como objetivo describir la relación entre el manejo forestal y algunos servicios ecosistémicos, en particular la conservación de la diversidad vegetal, producción de madera, regulación de los flujos del agua y el secuestro y almacenamiento de carbono en bosques templados de México. Se revisaron varias bases de datos bibliográficos para encontrar los estudios más relacionados con estos temas, compilándose 57 trabajos. El manejo forestal se materializa a través de prácticas que incluyen aclareos, cortas de regeneración, selección y otros tratamientos complementarios. De manera general, el manejo forestal impacta de forma positiva el abastecimiento de madera (materia prima) y el secuestro y almacén de carbono. Tiene un efecto variable en la conservación de la diversidad vegetal y negativo en el abastecimiento de flujos de agua, al menos al inicio de la intervención silvícola. El impacto y resiliencia del ecosistema depende de la escala espacial y temporal de la perturbación. La identificación, cuantificación y evaluación de las interacciones de los servicios ecosistémicos en los bosques templados de México, puede ayudar a los tomadores de decisiones a minimizar los impactos posibles del manejo forestal sobre los servicios ecosistémicos.