Effects of copal resin extraction on the diversity and composition of species in tropical deciduous forests.

Composition and floristic diversity of ecosystems subject to overexploitation, such as tropical deciduous forests where copal resin (Bursera bipinnata, Bursera copallifera) is extracted, are of great importance for understanding the ecological functioning of these ecosystems. This study analyzed the species composition and diversity in a natural population subject to copal extraction in San Juan Raboso Izúcar de Matamoros, Puebla, Mexico. A total of 54 sampling units were established, and the number of individuals and crown diameter for each tree species were recorded. For shrubs, succulents, acaulescent rosetophytes and climbers, the number of individuals and the area of cover were quantified. Based on the parameters of abundance, frequency, and relative dominance, the importance value index (IVI) was calculated. Diversity was evaluated using the Shannon index [Formula: see text]. In total, 29 species were identified, distributed across 11 botanical families and 21 genera. The Fabaceae family was the richest, followed by the Burseraceae family, which includes the species that extract copal, but Opuntia streptacantha was the species with the most ecological weight. In this study, the Shannon index [Formula: see text] averaged 1.45, which indicates that the community was mildly diverse.

Influencia del hábitat en la diversidad de aves insectívoras en un sistema agroforestal enclavado en un Bosque Mesófilo de Montaña / Influence of the habitat on the diversity of insectivorous birds in agroforestry systems embedded in a Mountain Mesophilic Forest

Resumen Los sistemas agroforestales pueden representar importantes nichos ecológicos que coadyuven a la conservación de la diversidad avifaunística. El objetivo de este trabajo fue estimar y comparar la diversidad y uso de hábitat de aves insectívoras en sistemas agroforestales enclavados en un bosque mesófilo de montaña. Se efectuó el monitoreo de aves de agosto de 2018 a enero de 2019 en tres hábitats: café tradicional (CT), potrero (PT) y bosque mesófilo de montaña (BMM). Se determinaron índices de abundancia relativa (IAR), riqueza (Jacknife1), similitud (Jaccard) y diversidad (Shannon-Wiener). El IAR presentó valores bajos para los tres hábitats. El método Jacknife1 denotó una riqueza promedio considerable para las tres áreas (CT: 33.02, PT: 24.20, BMM: 9.98, CT-PT-BMM: 52.22). La técnica de Jaccard registró poca similitud en la riqueza, reafirmando el efecto del hábitat, composición y estructura florística como factores determinantes, al mismo tiempo que estableció promedios de diversidad alta obtenidos mediante el método de Shannon-Wiener (H´= 3.3; 3.1; 2.27; 3.78, respectivamente), revelando una diversidad relativamente estable en los tres hábitats. Por su parte, Kruskal-Wallis advirtió diferencias en la diversidad, pero no para la riqueza y la abundancia. Se evidenció la conformación declústeresy agrupaciones que encontraron mayor similitud entre la riqueza y la abundancia de especies por cada monitoreo aplicado. El análisis de componentes principales indicó mayor correlación del hábitat y la vegetación utilizados para la alimentación en el estrato herbáceo y arbóreo, en alturas que van de 5 m a 10 m, utilizando el estrato aéreo para vuelo. Los sistemas agroforestales estudiados constituyeron un nicho de oportunidad en donde la avifauna halló alimento, áreas de nidación y reproducción. Se recomienda la implementación de buenas prácticas de manejo agroforestal que coadyuven a la conservación de especies.

Abstract Agroforestry systems can represent important ecological niches that contribute to the conservation of bird diversity. The objective of this work was to estimate and compare the diversity and habitat use of insectivorous birds in agroforestry systems located in a montane cloud forest. Bird monitoring was carried out from August 2018 to January 2019 in three habitats: traditional coffee plantation (CT), paddock (PT) and montane cloud forest (BMM). Relative abundance (IAR), richness (Jacknife1), similarity (Jaccard) and diversity (Shannon-Wiener) indices were determined. The IAR presented low values for the three habitats. The Jacknife1 method denoted considerable average richness for the three areas (CT: 33.02, PT: 24.20, BMM: 9.98, CT-PT-BMM: 52.22). The Jaccard technique recorded little similarity in richness, reaffirming the effect of habitat, composition and floristic structure as determining factors, which at the same time established high diversity averages, obtained by the Shannon-Wiener method (H´= 3.3; 3.1 ; 2.27; 3.78, respectively), revealing a relatively stable diversity in the three habitats. For his part, Kruskal-Wallis noticed differences in diversity, but not for richness and abundance. The formation of clusters and groups that found greater similarity between the richness and abundance of species for each applied monitoring was evidenced. Principal component analysis indicated a higher correlation of habitat and vegetation used for feeding in the herbaceous and arboreal stratum, at heights ranging from 5 m to 10 m, using the aerial stratum for flight. The agroforestry systems studied constituted a niche of opportunity where the avifauna found food, nesting and reproduction areas. The implementation of good agroforestry management practices that contribute to the conservation of species is recommended.