Conserving Tropical Tree Diversity and Forest Structure: The Value of Small Rainforest Patches in Moderately-Managed Landscapes

Abstract

Rainforests are undergoing severe deforestation and fragmentation worldwide. A huge amount of small forest patches are being created, but their value in conserving biodiversity and forest structure is still controversial. Here, we demonstrate that in a species-rich and moderately-managed Mexican tropical landscape small rainforest patches (<100 ha) can be highly valuable for the conservation of tree diversity and forest structure. These patches showed diverse communities of native plants, including endangered species, and a new record for the country. Although the number of logged trees increased in smaller patches, patch size was a poor indicator of basal area, stem density, number of species, genera and families, and community evenness. Cumulative species-area curves indicated that all patches had a similar contribution to the regional species diversity. This idea also was supported by the fact that patches strongly differed in floristic composition (high β-diversity), independently of patch size. Thus, in agreement with the land-sharing approach, our findings support that small forest patches in moderately-managed landscapes should be included in conservation initiatives to maintain landscape heterogeneity, species diversity, and ecosystem services.

Conservation of the Ethiopian church forests: Threats, opportunities and implications for their management

“…Individual species occurred on average in only 13 out of the 78 sampled forest patches . Similar and even lower occurences of tree species have been found in other sets of small tropical forest fragments, for instance in tropical rainforest fragments in Los Tuxtlas, Mexico, where 41% of the recorded species occurred in only one or two patches (Arroyo-Rodriguez et al 2009), and in rainforest patches in Chiapas, Mexico, that shared on average only 27% of species (Hernandez-Ruedas et al 2014). Individual forests were also rather species-poor, each containing on average only 25 species of woody plants or 16.9% of the sampled species pool.…”

“…To maintain species diversity and associated ecosystem services, a high proportion of patches needs to be conserved (see also Hernandez-Ruedas et al 2014). This is because low frequencies of species entail high extinction risks when patches are lost, and because extinction risks are high in landscapes with low vegetation cover, low connectivity, degraded vegetation and intensive land use in the matrix (Fischer and Lindenmayer 2007).…”

Estructura de la selva alta perennifolia de Nahá, Chiapas, México

“…as selvas altas perennifolias representan uno de los ecosistemas más vulnerables en el mundo, al poseer los más elevados valores de riqueza de especies que cualquier otro ecosistema terrestre aunado a un fuerte deterioro debido a las actividades del ser humano (Challenger & Soberón 2008, Hernández-Ruedas et al 2014, Clark et al 2015, Durán-Fernández et al 2016. Según Leopold (1950), el área potencial de lo que denominó "tropical rain forest" era alrededor de 12.8 % de la superficie del territorio mexicano.…”

“…La región Lacandona preserva algunos de los remanentes más extensos de selvas altas perennifolias y mejor conservados en México y es refugio de un número importante de especies de flora y fauna (Martínez et al 1994, Levy-Tacher et al 2006, Van Breugel et al 2006, AvilaTorresagatón et al 2012, Garmendia et al 2013, Hernández-Ruedas et al 2014, Durán-Fernán-dez et al 2016. Es así que ha sido considerada como una de las áreas de mayor prioridad para la conservación de la biodiversidad en el país, a pesar de que en menos de cinco décadas su cobertura selvática ha disminuido en más del 50 %.…”

“…Es así que ha sido considerada como una de las áreas de mayor prioridad para la conservación de la biodiversidad en el país, a pesar de que en menos de cinco décadas su cobertura selvática ha disminuido en más del 50 %. Como consecuencia de las actividades humanas en las regiones tropicales del mundo, se aprecia una clara tendencia continua y creciente hacia la eliminación y modificación de las selvas húmedas, principalmente por: (i) aumento de la población humana y su correspondiente demanda de alimentos y otros recursos; (ii) extracciones desmesuradas de los recursos selváticos provocando fuertes procesos degradativos; (iii) orientaciones equívocas al considerar inagotables los recursos de la selva; y (iv) poca atención a su conservación y al desarrollo de sistemas de aprovechamiento persistente (Miranda 1975, Farnworth & Golley 1977, Nelson 1977, Muench-Navarro 1978, Rzedowski 1978, UNESCO 1980, Nations & Nigh 1980, Casco-Montoya 1984, Anderson 1990, Vaśquez-Sańchez & Ramos-Olmos 1992, FAO 1994, Martínez et al 1994, Challenger & Soberón 2008, Hernández-Ruedas et al 2014.…”