The effects of tropical secondary forest regeneration on avian phylogenetic diversity

The conversion of tropical forests to farmland is a key driver of the current extinction crisis. With the present rate of deforestation unlikely to subside, secondary forests that regenerate on abandoned agricultural land may provide an option for safeguarding biodiversity. While species richness (SR) may recover as secondary forests get older, the extent to which phylogenetic diversity (PD)—the total amount of evolutionary history present in a community—is conserved is less clear. Maximizing PD has been argued to be important to conserve both evolutionary heritage and ecosystem function. Here, we investigate the effects of secondary forest regeneration on PD in birds. The regeneration of secondary forests could lead to a community of closely related species, despite maintaining comparable SR to primary forests, and thus have diminished biodiversity value with reduced evolutionary heritage. We use a meta-dataset of paired primary and secondary forest sites to show that, over time, forest specialist species returned across all sites as secondary forest age increased. Forest specialists colonize secondary tropical forests in both the Old World and the New World, but recovery of PD and community composition with time is only evident in the Old World. Synthesis and applications. While preserving primary tropical forests remains a core conservation goal, our results emphasize the important role of secondary forest in maintaining tropical forest biodiversity. Biodiversity recovery differs between Old and New World secondary forests and with proximity to primary forest, highlighting the need to consider local or regional differences in landscape composition and species characteristics, especially resilience to forest degradation and dispersal capability. While farmland abandonment is increasing across marginal areas in the tropics, there remains a critical need to provide long-term management and protection from reconversion to maximize conservation benefits of secondary forests. Our study suggests such investments should be focused on land in close proximity to primary forests

Sexual behaviors and their correlates among young people in Mauritius: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Little is known about the HIV/AIDS epidemic in the Indian Ocean region, including Mauritius. National records suggest a prevalence of HIV in Mauritius of < 1% in the general population, which is one of the lowest prevalence rates in southern Africa. However, HIV-positive cases have been increasing recently in Mauritius. We conducted a cross-sectional survey in January 2003 to assess the prevalence of HIVrelated sexual behaviors and their correlates among young people aged 15–24 years in Mauritius.</p> <p>Methods</p> <p>We identified 1200 participants using two-stage cluster sampling. Demographic, social, sexual, and knowledge of HIV/AIDS data were obtained in face-to-face interviews using a structured questionnaire administered by trained interviewers. The prevalence of sexual behaviors was described in relation to gender, and the correlates of ever having had sex and nonuse of condom at last sex were analyzed using logistic regression.</p> <p>Results</p> <p>In the target population, 30.9% of males and 9.7% of females reported a history of sexual intercourse. Of the currently sexually active participants, 50.6% of men and 71.2% of women did not use condoms at their last sexual encounter. Logistic regression revealed that work experience and marijuana use were significantly associated with men's sexual experience, whereas being out of school and drinking experience were significantly associated with women's sexual experience. For both men and women, being Christian and visiting nightclubs were associated with having ever had sexual intercourse (P < 0.05). In addition, not using a condom at the first sexual encounter and lack of exposure to a nongovernmental organization (NGO) dealing with HIV/AIDS were associated with the nonuse of condoms at the last sexual encounter (P < 0.05).</p> <p>Conclusion</p> <p>Young people in Mauritius are at risk of a future HIV epidemic because behaviors predisposing to HIV infection are prevalent among sexually experienced youth. A focused prevention program targeting young people should be reinforced as part of the National AIDS Control Program, taking into account the predictors of sexual behaviors identified here.</p