A suite of ecological indicators for evaluating the integrity of structural eco-complexity in Mexican forests

This paper presents a conceptual framework for analyzing forest complexity as the combination of the variety of species and key structures that are associated with the composition, structure, and function of forest stands. Several spatial indicators have been developed to characterize the biodiversity, the structural complexity, and anthropogenic effects that can be observed in Mexican forests. By integrating several stand complexity attributes, the forest condition can be characterized as a function of species composition, stand structural attributes, and forest development. In addition, indicators of anthropogenic effects were also analyzed to identify their influence on forest eco-complexity, and therefore, on the current condition of forests. The results of applying this conceptual framework showed that Mexican forest are ecologically complex, with varying levels of anthropogenic impacts that modify the structural forest characteristics, particularly in tropical forests. The main factor explaining the current eco-complexity condition in tropical forests was associated with early stages of forest development, due to ecological degradation, and showed a generalized loss of attributes, particularly for stand complexity and stand development. In contrast, temperate forests exhibited better eco-complexity conditions, especially for those attributes that define forest stand occupancy and development. Mining activities, forest extraction as selective harvesting, forest fires, land use change, and road openings are critical human activities that directly affect forest structure and, ultimately, modify forest eco-complexity and integrity. This eco-complexity index derived for Mexican forests can be used to integrate measures of forest structure and functioning, and thereby better inform decision making and policy development.