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Abstract: Tropical forests provide a variety of goods and services to humanity. Although efforts to protect and manage these forests have increased in recent decades, forest loss continues. The last decade and a half has seen considerable research on reforestation with native species in Mesoamerica, including both biophysical and social aspects. Advances in knowledge have led to increasingly sophisticated reforestation treatments as well as novel ways of deriving forest goods and services from human dominated landscapes. This Special Issue includes articles produced as the result of a conference held in Panama City, Panama in January 2010 with the goal to summarize the state of knowledge of native species reforestation and associated ecosystems services in Mesoamerica. The introduction concludes with a call for continued research, including a mechanistic understanding of tree interactions with the biophysical environment in order to advance or knowledge of ecosystem services and their interactions. Results from these and other studies aimed at socioeconomic aspects of reforestation are critical to land use planning. [Copyright &y& Elsevier]

The meaning of the term biodiversity and the challenge of its evaluation are discussed in this paper. Requirements for its conservation within indigenous production forests are weighed in context of the homogeneity of rain forested landscapes for different organisms, and the impact of logging on biodiversity. A hypothesis, aimed at defining that method of management which can optimize both sustainable timber production and biodiversity conservation, is presented for testing by research. [ABSTRACT FROM AUTHOR]

Abstract: As managing forests for biodiversity becomes more common, it is important to understand how understory species respond to disturbance. We monitored changes in species’ dominance, calculated as importance values, over a 4-year period in order to determine how species’ dominance varied with disturbance intensity and gap position. An experimental linear canopy opening was created in a southern New England mixed-oak forest, and plots were established on the south side, center, and north side of the opening. All vegetation was removed in half of the plots, simulating a lethal disturbance. In the other half of the plots, only the overstory was removed, simulating minimal disturbance (release plot). Before the disturbance, Dennstaedtia punctilobula dominated the plots, but typical forest understory species such as Kalmia latifolia, Trientalis borealis, Maianthemum canadense, and Mitchella repens were very common. After the disturbance, D. punctilobula expanded and continued to remain dominant in all types of plots. Early successional species, such as Carex pensylvanica, Poaceae species, Rubus ideaus, and Rubus allegheniensis dominated the lethal and center plots; late successional forest understory species experienced a reduction in frequency and cover in these plots. However, in release and edge plots, late successional species maintained relatively similar frequencies and covers to pre-disturbance values. The ability of early successional species to seed into lethal plots and grow rapidly in the high light environment of the center plots allowed them to dominate in these plots. Late successional species were able to remain relatively dominant in release plots through clonal expansion and in edge plots through exclusion of early successional species from low light levels. Three years after the disturbance, most of the residual forest understory species had attained similar frequencies and covers to pre-disturbance values in all types of plots. Thus, although there is some initial loss of residual species in highly disturbed areas and in the center of the opening, most of these species are able to recover in a relatively short time period. However, locally uncommon species may be vulnerable to permanent loss. In order to minimize loss of species from the understory, forest managers should attempt to keep groundstory disturbance as minimal as possible where desirable late-successional species exist and create edge-partial shade effects with the remaining canopy for regeneration treatments. [Copyright &y& Elsevier]

We investigate the geographical and historical context of diversification in a complex of mutualistic Crematogaster ants living in Macaranga trees in the equatorial rain forests of Southeast Asia. Using mitochondrial DNA from 433 ant colonies collected from 32 locations spanning Borneo, Malaya and Sumatra, we infer branching relationships, patterns of genetic diversity and population history. We reconstruct a time frame for the ants’ diversification and demographic expansions, and identify areas that might have been refugia or centres of diversification. Seventeen operational lineages are identified, most of which can be distinguished by host preference and geographical range. The ants first diversified 16–20 Ma, not long after the onset of the everwet forests in Sundaland, and achieved most of their taxonomic diversity during the Pliocene. Pleistocene demographic expansions are inferred for several of the younger lineages. Phylogenetic relationships suggest a Bornean cradle and major axis of diversification. Taxonomic diversity tends to be associated with mountain ranges; in Borneo, it is greatest in the Crocker Range of Sabah and concentrated also in other parts of the northern northwest coast. Within-lineage genetic diversity in Malaya and Sumatra tends to also coincide with mountain ranges. A series of disjunct and restricted distributions spanning northern northwest Borneo and the major mountain ranges of Malaya and Sumatra, seen in three pairs of sister lineages, further suggests that these regions were rain-forest refuges during drier climatic phases of the Pleistocene. Results are discussed in the context of the history of Sundaland's rain forests. [ABSTRACT FROM AUTHOR]