Biophysical and Biocultural Upheavals in Mesoamerica, a Conservation Perspective: Mountains, Maize-Milpa, and Globalization

Abstract

Three upheavals shaped southern Mexico to Panama (SMP) biodiversity: 1. The Great American Interchange that allowed migrations between the Neotropical and the Nearctic biogeographic realms; 2. human colonization with the generation of Mesoamerican cultures; and 3. the Spaniards’ arrival and globalization.Tectonic events generated a narrow piece of land with steep topography and high environmental heterogeneity, demanding high levels of local adaptation. Habitat size is usually restricted and reduced by frequent disturbances. Topography imposes few options for individuals forced to displace. Thus, extinction risks should be unusually high. Humans initiated an ongoing defaunation process and introduced the maize and the milpa, an itinerant maize-based slash-and-burn polyculture, which depends on revegetation to re-establish soil fertility. Also, the milpa is a most important pre-Hispanic legacy, a biocultural and landrace reservoir actively affecting landscape configuration, succession, soil development, and the genetic architecture of the species. Unprecedented human epidemics and soil, biodiversity, and culture erosion followed behind the Spanish aftermath and the subsequent globalization. > 63 million people and ≈100 ethnic groups inhabit SMP in 2020, which, with the biota, share the same problems of climate change, disturbance, and acculturation. SMP has been the scenario of severe climate change, fastest and deadliest extinction events (amphibians), a most spectacular exotic-species invasion (Africanized honeybees), and accelerated deforestation, defaunation, and acculturation. Biocultural conflicts between native and non-native people are globalization byproducts and sources of habitat destruction and species decline. Bottom-up initiatives are likely the best option for conservation in indigenous areas, whereas honest (i.e., with truly conservation intentions) top-down initiatives are helpful if the affected people are considered subjects (no objects) of conservation plans. We suggest some unique areas requiring conservation attention and analyzed current conservation initiatives. Not a single initiative is best suited for all conservation needs in SMP. Protection of all successional stages is critical for resilience and revegetation. Conservation of the milpa system (crop fields and subsequent fallows) is an optimal option for minimizing tradeoffs between conservation and people needs and safeguarding traditional culture and local landraces but is limited to areas with indigenous people and may not work for species with large home ranges.

Mid‐ and long‐term ecological changes after enrichment planting with native tree species in Mexican tropical mountain forests

“…Within the time period of this study (30+ years), we did not find differences in soil variables in comparison to paired nearby plots under unassisted forest regeneration. This coincides with findings in southern Mexican cloud forests from Oaxaca (del Castillo & Blanco-Macías 2007;Negrete-Yankelevich et al 2007;Bautista-Cruz et al 2012), where soil changes were studied along several successional chronosequences spanning from cornfields up to old-growth stands with 100+ years without apparent disturbance. Contradictory trends in values of total organic carbon from early successional forest stages (15 years after agricultural abandonment), up to those in old-growth stands were reported by these authors.…”

“…Because of these wide arrays of disturbance regimes, multiple trajectories of secondary succession may occur, resulting in several alternative communities (Ramírez‐Marcial et al 2001; González‐Espinosa et al 2006). The resulting landscape from these land‐use changes includes a complex mosaic of intermediate and early secondary forests (fallows), scrublands, and permanent pastures and crop fields (González‐Espinosa et al 1991; Ochoa‐Gaona & González‐Espinosa 2000; del Castillo & Rivera‐García 2022). Similar consequences of this pattern of disturbance and forest degradation have been observed in other tropical highland regions of Mexico and Guatemala where traditional agricultural practices and firewood extraction have prevailed for centuries (Veblen 1976; Figueroa‐Rangel et al 2011; Harvey et al 2021).…”

“…Shade-tolerant species include long-lived oaks (Quercus spp. ), which may recruit early in succession but typically become dominant in the canopy of old-growth stands; other long-lived shade-tolerant broadleaved non oak species usually remain in the understory layer of mature forests (Gonz alez-Espinosa et al 1991;del Castillo & Blanco-Macías 2007).…”

Enhancing Tropical Artificial Forests With Cubic Picture Fuzzy Fairly Aggregation Operators

“…Step 1: In the MCDM process, a crucial step involves evaluating the importance assigned to each DM's expertise to determine their weight. The significance grade assessment, derived from their expertise-based evaluations, is quantified using Equation (8), which gives ζ 1 = 0.3990, ζ 2 = 0.2760, and ζ 3 = 0.3250. These values reflect the relative importance of each DM's expertise in the decisionmaking process.…”

“…One key consideration is the location's climate, as it affects the growth and survival of the target species. Tropical forests typically require a warm, humid climate with consistent rainfall throughout the year [8], and the location should have a suitable temperature range for the target species. The soil quality is also essential, affecting nutrient availability and waterholding capacity.…”