Responses of transplanted native tree species to invasive alien grass removals in an abandoned cattle pasture in the Lacandon region, Mexico

We tested the early performance of 16 native early-, mid-, and late-successional tree species in response to four intensities of grass removal in an abandoned cattle pasture dominated by the introduced, invasive African grass, Cynodon plectostachyus, within the Lacandon rainforest region, southeast Mexico. The increase in grass removals significantly improved the performance of many species, especially of early-and mid-successional species, while performance of late-successional species was relatively poor and did not differ significantly among treatments. Good site preparation and at least one additional grass removal four months after seedling transplant were found to be essential; additional grass removals led to improved significantly performance of saplings in most cases. In order to evaluate the potential of transplanting tree seedlings successfully in abandoned tropical pastures, we developed a "planting risk index", combining field performance measurements and plantation cost estimations. Our results showed a great potential for establishing restoration plantings with many early-and mid-successional species. Although planting risk of late-successional species was considered high, certain species showed some possibilities of acclimation after 18 months and should be considered in future plantation arrangements in view of their long-term contributions to biodiversity maintenance and also to human welfare through delivery of ecosystem services. Conducting a planting risk analysis can help avoid failure of restoration strategies involving simultaneous planting of early-, mid-, and late-successional tree species. This in turn will improve cost-effectiveness of initial interventions in large-scale, long-term restoration programs.

Dangerous waters: outbreak of eye lesions caused by fresh water sponge spicules

Purpose To describe an extremely uncommon outbreak of eye lesions in a specific area of the Brazilian Amazonia. Methods Prospective noncomparative case series. Fifty-nine patients who developed eye lesions after swimming in the Araguaia river of Tocantins state in Brazil were examined. A team of ophthalmologists equipped with a slit-lamp, gonioscopic lenses, and indirect ophthalmoscopy performed full eye examination. Analysis of the flora and fauna of the river water was undertaken by a group of experts. Results and Conclusions Eighty-three eyes were affected. The most common lesions were corneal opacities seen in 34 eyes and conjunctival nodules diagnosed in 12 eyes. Severe visual acuity loss was detected in seven children with unilateral anterior chamber lesions. Spicules of the sponge species Drulia uruguayensis and Drulia ctenosclera were found inside three blind eyes that have been enucleated for diagnostic purposes. All eye lesions could be attributed to an outbreak of foreign bodies from fresh water sponges. Organic enrichment of the water resulting from the absence of sanitation probably was the key factor, which initiated a cycle of ecological imbalance that provoked human disease.