Traditional Agroforestry Systems and Conservation of Native Plant Diversity of Seasonally Dry Tropical Forests

Abstract

Traditional agroforestry systems (TAFS), which integrate crops with wildlife, are important reservoirs of human culture and technical experiences with a high capacity for biodiversity conservation. Our study aimed to evaluate the capacity of TAFS to conserve the floristic diversity of tropical dry forests (TDF) in the Tehuacán-Cuicatlán Valley, Mexico. We compared TAFS and TDF by measuring their forest cover, floristic composition, and structure, in addition to documenting the motivations of people to maintain native vegetation in their agricultural fields. We conducted a restricted randomized sampling of perennial plant species, including nine sites of TAFS and nine of TDF to determine the alpha, beta, and gamma diversity. Furthermore, we conducted semi-structured interviews with peasants who managed the agricultural plots we studied. We also performed workshops with people of the communities where surveys were performed. Our findings show that TAFS can maintain, on average, 68% of the species (95% of them native to the region) and 53% of the abundance of individuals occurring in the adjacent TDF. TAFS harbour 30% (39 species) of plants endemic to Mexico. Total species richness of TDF and TAFS were similar, as well as the effective number of species or communities estimated for the alpha, beta, and gamma diversity, but differed in the abundance of individuals. The high species turnover recorded in TDF (72%) and TAFS (74%) has profound implications for conservation, suggesting that it would be necessary to maintain several sites in order to conserve the regional diversity of native vegetation. Material, non-material, and regulatory contributions were reported to be the reason that peasants take into account maintaining natural vegetation. TAFS associated with TDF in the region (also called “Apancles”) contain an important richness, diversity, and endemism of components of natural ecosystems, as well as provide multiple socio-ecological contributions. These systems could represent a viable alternative to reconcile biological conservation with social well-being.

Peasants’ Motivations to Maintain Vegetation of Tropical Dry Forests in Traditional Agroforestry Systems from Cuicatlán, Oaxaca, Mexico

“…Our study was conducted in the peasant communities of Santiago Quiotepec, Cuicatlán, and Santiago Dominguillo, where the land tenure is communal and ejidal (two forms of collective tenure regimes). These communities have primary activities like traditional "milpa" agriculture (a multi-crop system with maize, beans and squash), cultivation of fruit trees (lemon, mango, sapodilla, spondias plum, annona, black sapote) in irrigated areas, raising of goats, and gathering of timber and nontimber forest products (Brunel, 2008;Rendón-Sandoval et al, 2020).…”

“…For obtaining the information we carried out: 1) 10 semistructured interviews with peasants whose agricultural fields were sampled for previous ecological studies (see Rendón-Sandoval et al, 2020). These interviews yielded results that reached the principle of information saturation, which refers to the stage in qualitative data collection when collecting more data produces little important new information or understanding relevant to the research questions (Newing et al, 2011).…”

“…Nevertheless, this ecosystem is highly threatened, and its conservation is one priority worldwide (Janzen, 1988;Olson and Dinerstein, 2002). In Mexico, it is relevant its high level of endemism (Rendón-Sandoval et al, 2020), the highest of the TDF in the Neotropical region, with 60-73% of species restricted to the Mexican territory (Rzedowski, 1991;Banda et al, 2016).…”

“…It has been documented that TAFS provide multiple benefits or contributions to societies (Moreno-Calles et al, 2010;Altieri and Toledo, 2011;Vallejo et al, 2016;Rendón-Sandoval et al, 2020). Nature's contributions to people are all socio-ecological contributions that humans obtain from nature, including goods and functions from ecosystems (Díaz et al, 2018).…”

“…Previous studies have documented that both maintenance and removal of forest elements from agricultural fields are regulated by needs, values, or potential damage perceived and mediated through different management practices (Moreno-Calles et al, 2010, Moreno-Calles et al, 2012Blancas et al, 2013;Vallejo et al, 2014, Vallejo et al, 2015, Vallejo et al, 2016Rangel-Landa et al, 2017). In particular, our team previously documented that TAFS associated with TDF can harbor -on average-44% of forest cover, 68% of species (30% of them endemic to Mexico), and 53% of the individuals of plants from the neighboring wild vegetation; where 96 species of useful plants (73% of the total) were recorded (Rendón-Sandoval et al, 2020). Therefore, this study seeks to deepen the understanding of the most determinant motivations for maintaining vegetation in the peasants' parcels, and the contribution of their TAFS to human well-being.…”