49 research outputs found

    Global biogeography of coral recruitment: tropical decline and subtropical increase

    Get PDF
    Despite widespread climate-driven reductions of coral cover on tropical reefs, little attention has been paid to the possibility that changes in the geographic distribution of coral recruitment could facilitate beneficial responses to the changing climate through latitudinal range shifts. To address this possibility, we compiled a global database of normalized densities of coral recruits on settlement tiles (corals m(-2)) deployed from 1974 to 2012, and used the data therein to test for latitudinal range shifts in the distribution of coral recruits. In total, 92 studies provided 1253 records of coral recruitment, with 77 % originating from settlement tiles immersed for 3-24 mo, herein defined as long-immersion tiles (LITs); the limited temporal and geographic coverage of data from short-immersion tiles (SITs; deployed for 20 degrees latitude). These trends indicate that a global decline in coral recruitment has occurred since 1974, and the persistent reduction in the densities of recruits in equatorial latitudes, coupled with increased densities in sub-tropical latitudes, suggests that coral recruitment may be shifting poleward

    Economic Support to Patients in HIV and TB Grants in Rounds 7 and 10 from the Global Fund to Fight AIDS, Tuberculosis and Malaria.

    Get PDF
    People with TB and/or HIV frequently experience severe economic barriers to health care, including out-of-pocket expenses related to diagnosis and treatment, as well as indirect costs due to loss of income. These barriers can both aggravate economic hardship and prevent or delay diagnosis, treatment and successful outcome, leading to increased transmission, morbidity and mortality. WHO, UNAIDS and the ILO argue that economic support of various kinds is essential to enable vulnerable people to protect themselves from infection, avoid delayed diagnosis and treatment, overcome barriers to adherence, and avert destitution. This paper analyses successful country proposals to the Global Fund to Fight AIDS, Tuberculosis and Malaria that include economic support in Rounds 7 and 10; 36 and 20 HIV and TB grants in Round 7 and 32 and 26, respectively, in Round 10. Of these, up to 84 percent included direct or indirect economic support for beneficiaries, although the amount constituted a very small proportion of the total grant. In TB grants, the objectives of economic support were generally clearly stated, and focused on mechanisms to improve treatment uptake and adherence, and the case was most clearly made for MDR-TB patients. In HIV grants, the objectives were much broader in scope, including mitigation of adverse economic and social effects of HIV and its treatment on both patients and families. The analysis shows that economic support is on the radar for countries developing Global Fund proposals, and a wide range of economic support activities are in place. In order to move forward in this area, the wealth of country experience that exists needs to be collated, assessed and disseminated. In addition to trials, operational research and programme evaluations, more precise guidance to countries is needed to inform evidence-based decision about activities that are cost-effective, affordable and feasible

    Extinction Debt in Source-Sink Metacommunities

    Get PDF
    In an increasingly modified world, understanding and predicting the consequences of landscape alteration on biodiversity is a challenge for ecologists. To this end, metacommunity theory has developed to better understand the complexity of local and regional interactions that occur across larger landscapes. While metacommunity ecology has now provided several alternative models of species coexistence at different spatial scales, predictions regarding the consequences of landscape alteration have been done exclusively for the competition-colonization trade off model (CC). In this paper we investigate the effects of landscape perturbation on source-sink metacommunities. We show that habitat destruction perturbs the equilibria among species competitive effects within the metacommunity, driving both direct extinctions and an indirect extinction debt. As in CC models, we found a time lag for extinction following habitat destruction that varied in length depending upon the relative importance of direct and indirect effects. However, in contrast to CC models, we found that the less competitive species are more affected by habitat destruction. The best competitors can sometimes even be positively affected by habitat destruction, which corresponds well with the results of field studies. Our results are complementary to those results found in CC models of metacommunity dynamics. From a conservation perspective, our results illustrate that landscape alteration jeopardizes species coexistence in patchy landscapes through complex indirect effects and delayed extinctions patterns

    How Plastic Can Phenotypic Plasticity Be? The Branching Coral Stylophora pistillata as a Model System

    Get PDF
    Phenotypic plasticity enables multicellular organisms to adjust morphologies and various life history traits to variable environmental challenges. Here, we elucidate fixed and plastic architectural rules for colony astogeny in multiple types of colonial ramets, propagated by cutting from genets of the branching coral Stylophora pistillata from Eilat, the Red Sea. We examined 16 morphometric parameters on 136 one-year old S. pistillata colonies (of seven genotypes), originating from small fragments belonging, each, to one of three single-branch types (single tips, start-up, and advanced bifurcating tips) or to structural preparative manipulations (representing a single or two growth axes). Experiments were guided by the rationale that in colonial forms, complexity of evolving phenotypic plasticity can be associated with a degree of structural modularity, where shapes are approached by erecting iterative growth patterns at different levels of coral-colony organization. Analyses revealed plastic morphometric characters at branch level, and predetermined morphometric traits at colony level (only single trait exhibited plasticity under extreme manipulation state). Therefore, under the experimental manipulations of this study, phenotypic plasticity in S. pistillata appears to be related to branch level of organization, whereas colony traits are controlled by predetermined genetic architectural rules. Each level of organization undergoes its own mode of astogeny. However, depending on the original ramet structure, the spherical 3-D colonial architecture in this species is orchestrated and assembled by both developmental trajectories at the branch level, and traits at the colony level of organization. In nature, branching colonial forms are often subjected to harsh environmental conditions that cause fragmentation of colony into ramets of different sizes and structures. Developmental traits that are plastic, responding to fragment structure and are not predetermine in controlling astogeny, allow formation of species-specific architecture product through integrated but variable developmental routes. This adaptive plasticity or regeneration is an efficient mechanism by which isolated fragments of branching coral species cope with external environmental forces

    Telephone Consultation for Improving Health of People Living with or at Risk of HIV: A Systematic Review

    Get PDF
    BACKGROUND: Low cost, effective interventions are needed to deal with the major global burden of HIV/AIDS. Telephone consultation offers the potential to improve health of people living with HIV/AIDS cost-effectively and to reduce the burden on affected people and health systems. The aim of this systematic review was to assess the effectiveness of telephone consultation for HIV/AIDS care. METHODS: We undertook a comprehensive search of peer-reviewed and grey literature. Two authors independently screened citations, extracted data and assessed the quality of randomized controlled trials which compared telephone interventions with control groups for HIV/AIDS care. Telephone interventions were voice calls with landlines or mobile phones. We present a narrative overview of the results as the obtained trials were highly heterogeneous in design and therefore the data could not be pooled for statistical analysis. RESULTS: The search yielded 3321 citations. Of these, nine studies involving 1162 participants met the inclusion criteria. The telephone was used for giving HIV test results (one trial) and for delivering behavioural interventions aimed at improving mental health (four trials), reducing sexual transmission risk (one trial), improving medication adherence (two trials) and smoking cessation (one trial). Limited effectiveness of the intervention was found in the trial giving HIV test results, in one trial supporting medication adherence and in one trial for smoking cessation by telephone. CONCLUSIONS: We found some evidence of the benefits of interventions delivered by telephone for the health of people living with HIV or at risk of HIV. However, only limited conclusions can be drawn as we only found nine studies for five different interventions and they mainly took place in the United States. Nevertheless, given the high penetration of low-cost mobile phones in countries with high HIV endemicity, more evidence is needed on how telephone consultation can aid in the delivery of HIV prevention, treatment and care

    Contrasting Light Spectra Constrain the Macro and Microstructures of Scleractinian Corals

    Get PDF
    The morphological plasticity of scleractinian corals can be influenced by numerous factors in their natural environment. However, it is difficult to identify in situ the relative influence of a single biotic or abiotic factor, due to potential interactions between them. Light is considered as a major factor affecting coral skeleton morphology, due to their symbiotic relation with photosynthetic zooxanthellae. Nonetheless, most studies addressing the importance of light on coral morphological plasticity have focused on photosynthetically active radiation (PAR) intensity, with the effect of light spectra remaining largely unknown. The present study evaluated how different light spectra affect the skeleton macro- and microstructures in two coral species (Acropora formosa sensu Veron (2000) and Stylophora pistillata) maintained under controlled laboratory conditions. We tested the effect of three light treatments with the same PAR but with a distinct spectral emission: 1) T5 fluorescent lamps with blue emission; 2) Light Emitting Diodes (LED) with predominantly blue emission; and 3) Light Emitting Plasma (LEP) with full spectra emission. To exclude potential bias generated by genetic variability, the experiment was performed with clonal fragments for both species. After 6 months of experiment, it was possible to detect in coral fragments of both species exposed to different light spectra significant differences in morphometry (e.g., distance among corallites, corallite diameter, and theca thickness), as well as in the organization of their skeleton microstructure. The variability found in the skeleton macro- and microstructures of clonal organisms points to the potential pitfalls associated with the exclusive use of morphometry on coral taxonomy. Moreover, the identification of a single factor influencing the morphology of coral skeletons is relevant for coral aquaculture and can allow the optimization of reef restoration efforts

    Time constraints do not limit group size in arboreal guenons but do explain community size and distribution patterns

    Get PDF
    To understand how species will respond to environmental changes, it is important to know how those changes will affect the ecological stress that animals experience. Time constraints can be used as indicators of ecological stress. Here we test whether time constraints can help us understand group sizes, distribution patterns and community sizes of forest guenons (Cercopithecus/Allochrocebus). Forest guenons typically live in small to medium sized one-male multi-female groups and often live in communities with multiple forest guenon species. We developed a time-budget model using published data on time budgets, diets, body sizes, climate, and group sizes to predict maximum ecologically tolerable group and community sizes of forest guenons across 202 sub-Saharan African locations. The model correctly predicted presence/absence at 83% of these locations. Feeding-foraging time (an indicator of competition) limited group sizes, while resting and moving time constraints shaped guenon biogeography. Predicted group sizes were greater than observed group sizes but comparable to community sizes, suggesting community sizes are set by competition among guenon individuals irrespective of species. We conclude that time constraints and intra-specific competition are unlikely to be the main determinants of relatively small group sizes in forest guenons. Body mass was negatively correlated with moving time, which may give larger bodied species an advantage over smaller bodied species under future conditions when greater fragmentation of forests is likely to lead to increased moving time. Resting time heavily depended on leaf consumption and is likely to increase under future climatic conditions when leaf quality is expected to decrease
    corecore