Network Structure of Vertebrate Scavenger Assemblages at the Global Scale: Drivers and Ecosystem Functioning Implications

The organization of ecological assemblages has important implications for ecosystem functioning, but little is known about how scavenger communities organize at the global scale. Here, we test four hypotheses on the factors affecting the network structure of terrestrial vertebrate scavenger assemblages and its implications on ecosystem functioning. We expect scavenger assemblages to be more nested (i.e. structured): 1) in species‐rich and productive regions, as nestedness has been linked to high competition for carrion resources, and 2) regions with low human impact, because the most efficient carrion consumers that promote nestedness are large vertebrate scavengers, which are especially sensitive to human persecution. 3) We also expect climatic conditions to affect assemblage structure, because some scavenger assemblages have been shown to be more nested in colder months. Finally, 4) we expect more organized assemblages to be more efficient in the consumption of the resource. We first analyzed the relationship between the nestedness of the scavenger assemblages and climatic variables (i.e. temperature, precipitation, temperature variability and precipitation variability), ecosystem productivity and biomass (i.e. NDVI) and degree of human impact (i.e. human footprint) using 53 study sites in 22 countries across five continents. Then, we related structure (i.e. nestedness) with its function (i.e. carrion consumption rate). We found a more nested structure for scavenger assemblages in regions with higher NDVI values and lower human footprint. Moreover, more organized assemblages were more efficient in the consumption of carrion. However, our results did not support the prediction that the structure of the scavenger assemblages is directly related to climate. Our findings suggest that the nested structure of vertebrate scavenger assemblages affects its functionality and is driven by anthropogenic disturbance and ecosystem productivity worldwide. Disarray of scavenger assemblage structure by anthropogenic disturbance may lead to decreases in functionality of the terrestrial ecosystems via loss of key species and trophic facilitation processes

Scavenging in the Anthropocene: Human impact drives vertebrate scavenger species richness at a global scale

Understanding the distribution of biodiversity across the Earth is one of the most challenging questions in biology. Much research has been directed at explaining the species latitudinal pattern showing that communities are richer in tropical areas; however, despite decades of research, a general consensus has not yet emerged. In addition, global biodiversity patterns are being rapidly altered by human activities. Here, we aim to describe large‐scale patterns of species richness and diversity in terrestrial vertebrate scavenger (carrion‐consuming) assemblages, which provide key ecosystem functions and services. We used a worldwide dataset comprising 43 sites, where vertebrate scavenger assemblages were identified using 2,485 carcasses monitored between 1991 and 2018. First, we evaluated how scavenger richness (number of species) and diversity (Shannon diversity index) varied among seasons (cold vs. warm, wet vs. dry). Then, we studied the potential effects of human impact and a set of macroecological variables related to climatic conditions on the scavenger assemblages. Vertebrate scavenger richness ranged from species‐poor to species rich assemblages (4–30 species). Both scavenger richness and diversity also showed some seasonal variation. However, in general, climatic variables did not drive latitudinal patterns, as scavenger richness and diversity were not affected by temperature or rainfall. Rainfall seasonality slightly increased the number of species in the community, but its effect was weak. Instead, the human impact index included in our study was the main predictor of scavenger richness. Scavenger assemblages in highly human‐impacted areas sustained the smallest number of scavenger species, suggesting human activity may be overriding other macroecological processes in shaping scavenger communities. Our results highlight the effect of human impact at a global scale. As speciesrich assemblages tend to be more functional, we warn about possible reductions in ecosystem functions and the services provided by scavengers in human‐dominated landscapes in the Anthropocene

Functional biogeography of vertebrate scavengers drives carcass removal across biomes

Resumen del trabajo presentado en el XVI Congreso Nacional de la AEET 2023: la ecología en una biosfera humanizada, celebrado en Almería entre el 16 y el 20 de octubre de 2023.Vertebrate scavengers play a crucial role in food web stability and cycling of organic matter and nutrients. However, the global factors that influence their functional biogeography and impact on ecosystem functioning at regional and local levels remain poorly understood. We aim to address this challenge by analyzing a global dataset covering 49 regions in all inhabited continents, including information on 1,847 locally monitored carcasses and 204 vertebrate scavenger species along with their functional traits. We investigate the importance of biogeographical (spatial), environmental and anthropogenic factors in structuring vertebrate scavengers¿ functional trait composition, diversity and abundance. Additionally, we investigate how these biodiversity attributes affect carcass removal at regional and local scales. Our results show that the functional trait composition of assemblages across studied regions was primarily explained by latitude and lon¬gitude, suggesting a strong biogeographical signature. In addition, while functional richness remained unexplained, scavenger abundance responded to both environmental and spatial factors. Further, we found that carcass removal was mainly driven by functional composition, but with the relative importance of particular functional traits varying from local to regional scales. At the local scale, carcass removal was positively related to large carnivorous species with large home ranges, while at the regional scale, carcass removal was better explained by the presence of vultures, other raptors and diurnal birds. Our study provides a better understanding of the factors controlling the func¬tional biogeography of terrestrial vertebrates and their role in maintaining essential ecological functions and services.Peer reviewe

Pregnancy Desire, Partner Serodiscordance, and Partner HIV Disclosure among Reproductive Age HIV-Infected Women in an Urban Clinic

Women comprise 25% of the US HIV epidemic, with many women of reproductive age. There is a need for providers to address the reproductive needs and desires of women with HIV given that effective antiretroviral therapy has transformed HIV into a chronic disease. This cross-sectional study shows high rates of partner serodiscordance (61%) and moderate HIV disclosure to partners (61%). Patients surveyed reported practitioners discuss condoms (94%) and contraception (71%) more often than pregnancy desire (38%). In our sample, 44% of the surveyed women intended future pregnancy, whereas women who did not intend future pregnancy cited HIV/health and serodiscordance as the most common reasons (56% and 35%, resp.). There was no difference in the knowledge of mother-to-child transmission risk between women who intended or did not intend future pregnancy (p=0.71). These results underline the need for provider training in reproductive counseling to promote risk reduction and education

Disclosure among Reproductive Age HIV-Infected Women in an Urban Clinic

Women comprise 25% of the US HIV epidemic, with many women of reproductive age. There is a need for providers to address the reproductive needs and desires of women with HIV given that effective antiretroviral therapy has transformed HIV into a chronic disease. This cross-sectional study shows high rates of partner serodiscordance (61%) and moderate HIV disclosure to partners (61%). Patients surveyed reported practitioners discuss condoms (94%) and contraception (71%) more often than pregnancy desire (38%). In our sample, 44% of the surveyed women intended future pregnancy, whereas women who did not intend future pregnancy cited HIV/health and serodiscordance as the most common reasons (56% and 35%, resp.). There was no difference in the knowledge of mother-to-child transmission risk between women who intended or did not intend future pregnancy ( = 0.71). These results underline the need for provider training in reproductive counseling to promote risk reduction and education

Human Immunodeficiency Virus (HIV) Quality Indicators Are Similar Across HIV Care Delivery Models

Abstract Background. There are limited data on human immunodeficiency virus (HIV) quality indicators according to model of HIV care delivery. Comparing HIV quality indicators by HIV care model could help inform best practices because patients achieving higher levels of quality indicators may have a mortality benefit. Methods. Using the Partners HIV Cohort, we categorized 1565 patients into 3 HIV care models: infectious disease provider only (ID), generalist only (generalist), or infectious disease provider and generalist (ID plus generalist). We examined 12 HIV quality indicators used by 5 major medical and quality associations and grouped them into 4 domains: process, screening, immunization, and HIV management. We used generalized estimating equations to account for most common provider and multivariable analyses adjusted for prespecified covariates to compare composite rates of HIV quality indicator completion. Results. We found significant differences between HIV care models, with the ID plus generalists group achieving significantly higher quality measures than the ID group in HIV management (94.4% vs 91.7%, P = .03) and higher quality measures than generalists in immunization (87.8% vs 80.6%, P = .03) in multivariable adjusted analyses. All models achieved rates that equaled or surpassed previously reported quality indicator rates. The absolute differences between groups were small and ranged from 2% to 7%. Conclusions. Our results suggest that multiple HIV care models are effective with respect to HIV quality metrics. Factors to consider when determining HIV care model include healthcare setting, feasibility, and physician and patient preference

Non-Communicable Disease Preventive Screening by HIV Care Model

<div><p>Importance</p><p>The Human Immunodeficiency Virus (HIV) epidemic has evolved, with an increasing non-communicable disease (NCD) burden emerging and need for long-term management, yet there are limited data to help delineate the optimal care model to screen for NCDs for this patient population.</p><p>Objective</p><p>The primary aim was to compare rates of NCD preventive screening in persons living with HIV/AIDS (PLWHA) by type of HIV care model, focusing on metabolic/cardiovascular disease (CVD) and cancer screening. We hypothesized that primary care models that included generalists would have higher preventive screening rates.</p><p>Design</p><p>Prospective observational cohort study.</p><p>Setting</p><p>Partners HealthCare System (PHS) encompassing Brigham & Women’s Hospital, Massachusetts General Hospital, and affiliated community health centers.</p><p>Participants</p><p>PLWHA age >18 engaged in active primary care at PHS.</p><p>Exposure</p><p>HIV care model categorized as infectious disease (ID) providers only, generalist providers only, or ID plus generalist providers.</p><p>Main Outcome(s) and Measures(s)</p><p>Odds of screening for metabolic/CVD outcomes including hypertension (HTN), obesity, hyperlipidemia (HL), and diabetes (DM) and cancer including colorectal cancer (CRC), cervical cancer, and breast cancer.</p><p>Results</p><p>In a cohort of 1565 PLWHA, distribution by HIV care model was 875 ID (56%), 90 generalists (6%), and 600 ID plus generalists (38%). Patients in the generalist group had lower odds of viral suppression but similar CD4 counts and ART exposure as compared with ID and ID plus generalist groups. In analyses adjusting for sociodemographic and clinical covariates and clustering within provider, there were no significant differences in metabolic/CVD or cancer screening rates among the three HIV care models.</p><p>Conclusions</p><p>There were no notable differences in metabolic/CVD or cancer screening rates by HIV care model after adjusting for sociodemographic and clinical factors. These findings suggest that HIV patients receive similar preventive health care for NCDs independent of HIV care model.</p></div

Odds of comparative diabetes screening events by specific screening types (A1C vs. fasting glucose).

<p>Odds ratios and 95% confidence intervals are shown for for unadjusted and adjusted analyses.</p

Metabolic/CVD and Cancer Screening Rates by HIV Care Model.

<p>Metabolic/CVD and Cancer Screening Rates by HIV Care Model.</p