Land Change in the Southern Yucatán and Calakmul Biosphere Reserve: Effects on Habitat and Biodiversity

Abstract

The southern Yucatán contains the largest expanse of seasonal tropical forests remaining in Mexico, forming an ecocline between the drier north of the peninsula and the humid Petén, Guatemala. The Calakmul Biosphere Reserve resides in the center of this region as part of the Mesoamerican Biological Corridor. The reserve's functions are examined in regard to land changes throughout the region, generated over the last 40 years by increasing settlement and the expansion and intensification of agriculture. These changes are documented from 1987/1988 to 2000, and their implications regarding the capacity of the reserve to protect the ecocline, forest habitats, and butterfly diversity are addressed. The results indicate that the current landscape matrix serves the biotic diversity of the reserve, with several looming caveats involving the loss of humid forests and the interruption of biota flow across the ecocline, and the amount and proximity of older forest patches beyond the reserve. The highly dynamic land cover changes underway in this economic frontier warrant an adaptive management approach that monitors the major changes underway in mature forest types, while the paucity of systematic ecological and environment-development studies is rectified in order to inform policy and practice.

Ecological feedbacks following deforestation create the potential for a catastrophic ecosystem shift in tropical dry forest

“…Furthermore, clearing mature forest is unlikely because current policies promote cultivation on extant open land or secondary forest. We have not observed either an increase in fallow length or an increase in deforestation of previously uncut forest (42). Adding fertilizer P is not economically viable at present but could be in the future.…”

“…We also sampled bulk deposition of P at an open field. Previous work in ER has shown that forests such as these would be 5.7, 9.3, and 12.1 m tall, with a density of 70, 550, and 880 trees per hectare Ͼ10 cm diameter at breast height, respectively (42). In each stand, fourteen 10-liter plastic buckets were dispersed every 3 m along three 15-m-long transects.…”

Fire Data as Proxy for Anthropogenic Landscape Change in the Yucatán

“…Unless interrupted by specific disturbances such as fire-friendly plant invasion or management practices, post-fire vegetation grows back at a rapid rate after a burn. In much of the Yucatán Peninsula, secondary vegetation can reach a height of 10 m within-five years of clearing [36][37][38]. As a consequence, there is typically only a short window of time to detect land change.…”

Distribución histórica de las especies del género Haematoxylum (Leguminosae) en la Península de Yucatán, México, basada en ejemplares de herbario

“…No se cuenta con información suficiente sobre H. calakmulense y el estado de conservación de sus poblaciones, al ser reconocida como nueva especie hace poco tiempo. Las principales amenazas a que se han enfrentado estas especies están relacionadas con las diferentes actividades antropogénicas que se han desarrollado en sus hábitats (Rico y García, 1991;Escalante y Aroche, 2000), las cuales se mantienen en la actualidad (Roy y Turner II, 2006;Vester et al, 2007).…”