Maximum plant-community endemism at intermediate intensities of anthropogenic disturbance in Bolivian Montane Forests

• Published in: Conservation biology Vol. 15; no. 3; pp. 634 - 641
• Main Author: Kessler, Michael
• Format: Journal Article
• Language: English
• Published: Boston, MA, USA Blackwell Science Inc 01.06.2001; Blackwell Science; Blackwell
• Subjects: Animal, plant and microbial ecology; Applied ecology; Araceae; Arecaceae; biodiversity; Biodiversity conservation; Biological and medical sciences; Bolivia; Bromeliaceae; Conservation biology; Conservation, protection and management of environment and wildlife; Endemic species; Forest conservation; Forest habitats; Fundamental and applied biological sciences. Psychology; Habitat conservation; human activity; indigenous species; Montane forests; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; plant communities; Plants; Pteridophyta; Species; Tropical forests; Bolivia; South America; Andes; America; Monocotyledones; Gradient; Endemic species; Plant community; Environmental factor; Tropical forest; Perturbation; Tropical montane forest; Pteridophyta; Araceae; Angiospermae; Spermatophyta; Bromeliaceae; Palmae; Anthropogenic factor
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1046/j.1523-1739.2001.015003634.x

I compared the endemism of four plant groups (Araceae, Bromeliaceae, Palmae, Pteridophyta) along gradients of increasing anthropogenic forest disturbance, from undisturbed mature forest to disturbed forest (logged, grazed, or burned), secondary forest, secondary scrub, and finally pasture, at 16 sites in the Bolivian Andes. I measured endemism as the mean inverse range size (number of 1° cells) of all species per study group encountered in each habitat and site. Overall, endemism was significantly higher in disturbed forest than in mature forest, but it declined in more strongly disturbed habitats. To explain the relationship of range size to habitat disturbance, I propose that endemic species are somewhat competitively inferior to other co-occurring taxa, limited in their ability to establish and maintain new populations following dispersal and thus to expand their ranges. Within their established ranges, endemic species depend on natural habitat disturbances to prevent their competitive exclusion by other species, so they profit from a certain level of anthropogenic disturbance. This pattern and the explanatory hypotheses should be subjected to critical evaluation. Although the pattern does not apply to every endemic tropical plant species, it indicates that conservation of part of the endemic tropical forest flora may be achieved in forest areas subject to sustainable forest use without the need to completely exclude human activities.