An assessment of natural and human disturbance effects on Mexican ecosystems: current trends and research gaps

Abstract

Mexico harbors more than 10% of the planet's endemic species. However, the integrity and biodiversity of many ecosystems is experiencing rapid transformation under the influence of a wide array of human and natural disturbances. In order to disentangle the effects of human and natural disturbance regimes at different spatial and temporal scales, we selected six terrestrial (temperate montane forests, montane cloud forests, tropical rain forests, tropical semi-deciduous forests, tropical dry forests, and deserts) and four aquatic (coral reefs, mangrove forests, kelp forests and saline lakes) ecosystems. We used semiquantitative statistical methods to assess (1) the most important agents of disturbance Electronic supplementary material The online version of this article (affecting the ecosystems, (2) the vulnerability of each ecosystem to anthropogenic and natural disturbance, and (3) the differences in ecosystem disturbance regimes and their resilience. Our analysis indicates a significant variation in ecological responses, recovery capacity, and resilience among ecosystems. The constant and widespread presence of human impacts on both terrestrial and aquatic ecosystems is reflected either in reduced area coverage for most systems, or reduced productivity and biodiversity, particularly in the case of fragile ecosystems (e.g., rain forests, coral reefs). In all cases, the interaction between historical human impacts and episodic high intensity natural disturbance (e.g., hurricanes, fires) has triggered a reduction in species diversity and induced significant changes in habitat distribution or species dominance. The lack of monitoring programs assessing before/after effects of major disturbances in Mexico is one of the major limitations to quantifying the commonalities and differences of disturbance effects on ecosystem properties.

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

“…However, the area occupied by the categories associated with disturbance or modified vegetation was also significant. Urban and bare soil areas increased progressively by more than 40.00 km 2 Regarding the adjacent areas, outside the NPAAC, the Scrub vegetation was the dominant category during almost the entire evaluated period, with a proportion of 26.41% and 33.1% of the total adjacent area; except for the year 2000, when Temperate forests represented the most extensive cover (162.3312 km 2 ). However, the area occupied by the categories associated with disturbance or modified vegetation was also significant.…”

“…The analysis extended from 1973 to 2015 in order to summarize the process of the LULCC over the 42-year period. The units in the change matrix were obtained as km 2 and percentages, and were calculated separately for the interior and exterior of the NPA.…”

“…However, the area occupied by the categories associated with disturbance or modified vegetation was also significant. Urban and bare soil areas increased progressively by more than 40.00 km 2 …”

“…It can be due to a variety of causes, both anthropogenic and natural, including forest fires, urbanization, and land modification as a result of intense agricultural and livestock activities [2]. These factors modify the structure of vegetation, and cause the loss of original plant cover [3][4][5].…”

Vegetation patch dynamics and tree diversity in a diverse conifer and oak forest in central Mexico

“…Conifer and oak forests were largely converted to agriculture since the beginning of Spanish colonization (1521) on the plateaus and montane valleys of central Mexico (Challenger, 2003). Where such forests are still dominant, their structure, composition and area remain affected by natural and human disturbances, particularly cattle grazing, and forest management (Minnich et al, 2000;Mas et al, 2004, Calderon-Aguilera et al, 2012. In this study we analyze patch dynamics in a conifer and oak forest in Aguascalientes State in Central Mexico, and evaluate the implications for these dynamics in terms of tree diversity preservation.…”