Ecological disturbance regimes caused by agricultural land uses and their effects on tropical forest regeneration

Abstract

Aims: Across tropical regions, large forest areas have been converted to different agricultural land uses. These uses impose ecological disturbances affecting forest regeneration potential after field abandonment. Finding ways to identify those agricultural land uses limiting forest regeneration is a critical issue for conserving biodiversity in human-modified landscapes. Here, we developed a fast and inexpensive index, useful for quantifying ecological disturbance regimes associated with agricultural land uses, and tested its power to predict forest regeneration potential.Location: Municipality of Marqu es de Comillas, southeast Mexico.Methods: Interviews were conducted with local farmers to quantify disturbance components (size, duration and severity) associated with agricultural land uses. The scaled values of these disturbance components were added in a simple ecological disturbance index (EDI). In each one of nine recently abandoned fields representing a wide range of EDI values, two 10-m 2 plots, one close to and one far from nearby forest remnants, were established. On each plot, all woody plants of 10-100 m in height were counted, identified and measured in four 1m 2 subplots, at the time of field abandonment and 2 yr later. In addition, at each plot, 18 site condition (microclimate and soil) attributes were quantified at the time of abandonment. Plant density, biomass, species richness and species diversity were used as regeneration variables, and EDI and site condition attributes as independent ones.Results: Two years after abandonment, most regeneration variables declined exponentially with EDI. Biomass was not explained by EDI but changed positively with light availability. EDI was strongly correlated to vapour pressure deficit, which also predicted regeneration potential (except biomass).Conclusions: EDI is a cheap and easy tool for quantifying the ecological disturbance produced by a wide range of agricultural land uses. The index predicted several regeneration variables as well as or better than direct measurements of the site condition at the time of abandonment. EDI can be used to identify biodiversity-friendly agricultural land uses in human-modified landscapes.

Assessment of Land Use-Cover Changes and Successional Stages of Vegetation in the Natural Protected Area Altas Cumbres, Northeastern Mexico, Using Landsat Satellite Imagery

“…After major disturbances where the removal of vegetation was complete, or nearly so [71], it has been recognized that early stages of succession post disturbance are characterized by dominance of pioneer species such as grasses, shrubs, and other short-lived species [72,73]. Therefore, besides the evidently disturbed bare-soil areas, we include the low and dense herbaceous vegetation in the disturbance category as early transition stages for Scrub vegetation, because the abandonment of cultivars, grasslands and other disturbed areas is related to recovery of the vegetation [74]. In this regard, evidence shows that abandonment of cultivated areas and pasture fields results in the development of thorny vegetation [75], this being one of the communities considered within the Scrub vegetation in our study.…”

Effects of livestock management on the supply of ecosystem services in pastures in a tropical dry region of western Mexico

“…We characterized the livestock management regimes using a set of indicators using an ad hoc approach drawing from the growing literature on ecological, agronomic and socio-ecological assessments of ecosystem management (Alkemade et al, 2013;Van Oudenhoven, 2015;Zermeño-Hernández et al, 2015). The land use is pasture for livestock production and the land management involves planting alien grasses, slashing and burning for pasture maintenance, and managing livestock by modifying stocking density and grazing periods, which together comprise the components of these management regimes.…”

“…From a social-ecological perspective (Reyers et al, 2013), management regimes are also dependent on the biophysical and social conditions within which the different management practices are undertaken (Van Oudenhoven, 2015). While a range of management regime indicators (Alkemade et al, 2013;Zermeño-Hernández et al, 2015) have been derived from the intersection of these approaches, and the range of ecosystem service indicators is growing (Layke et al, 2012;Van Oudenhoven et al, 2012), the impact of alternative management regimes and their components on ecosystem services needs to be further assessed.…”

Agricultural land-use diversity and forest regeneration potential in human- modified tropical landscapes

“…In the tropics, however, there is a wide array of agricultural land uses, and their impact on forest regeneration potential, once a field is abandoned, is poorly known (Melo et al, 2013;Zermeño-Hernández et al, 2015). In this context, a first step for exploring agriculture land uses which are friendly to biodiversity conservation is to quantify the diversity of agricultural land uses in the landscape, assess the ecological disturbance regimes imposed by such uses, and evaluate the impact of these disturbance regimes on forest regeneration potential (Zermeño-Hernández et al, 2015). Because in recent times there has been a global trend of land abandonment in the tropics (Cramer et al, 2008;Aide et al, 2013), this issue is of wide relevance.…”

“…We based this analysis on an ecological disturbance index (EDI) we developed elsewhere with information provided by farmers and landowners (Zermeño-Hernández et al, 2015). We have shown that EDI is an inexpensive, quickly and efficiently predictor of forest regeneration potential at the field scale; we proved that plant density, richness, and species diversity of regenerating forest trees decrease exponentially as EDI increases.…”