RESUMO
Scavenging by large carnivores is integral for ecosystem functioning by limiting the build-up of carrion and facilitating widespread energy flows. However, top carnivores have declined across the world, triggering trophic shifts within ecosystems. Here, we compare findings from previous work on predator decline against areas with recent native mammalian carnivore loss. Specifically, we investigate top-down control on utilization of experimentally placed carcasses by two mesoscavengers-the invasive feral cat and native forest raven. Ravens profited most from carnivore loss, scavenging for five times longer in the absence of native mammalian carnivores. Cats scavenged on half of all carcasses in the region without dominant native carnivores. This was eight times more than in areas where other carnivores were at high densities. All carcasses persisted longer than the three-week monitoring period in the absence of native mammalian carnivores, while in areas with high carnivore abundance, all carcasses were fully consumed. Our results reveal that top-carnivore loss amplifies impacts associated with carnivore decline-increased carcass persistence and carrion access for smaller scavengers. This suggests that even at low densities, native mammalian carnivores can fulfil their ecological functions, demonstrating the significance of global carnivore conservation and supporting management approaches, such as trophic rewilding.
Assuntos
Carnívoros , Ecossistema , Gatos , Animais , Cadeia Alimentar , Comportamento Predatório , Aves , PeixesRESUMO
Global road networks facilitate habitat modification and are integral to human expansion. Many animals, particularly scavengers, use roads as they provide a reliable source of food, such as carrion left after vehicle collisions. Tasmania is often cited as the 'roadkill capital of Australia', with the isolated offshore islands in the Bass Strait experiencing similar, if not higher, levels of roadkill. However, native mammalian predators on the islands are extirpated, meaning the remaining scavengers are likely to experience lower interference competition. In this study, we used a naturally occurring experiment to examine how the loss of mammalian carnivores within a community impacts roadside foraging behaviour by avian scavengers. We monitored the locations of roadkill and forest ravens Corvus tasmanicus, an abundant scavenger species, on eight road transects across the Tasmanian mainland (high scavenging competition) and the Bass Strait islands (low scavenging competition). We represented raven observations as one-dimensional point patterns, using hierarchical Bayesian models to investigate the dependence of raven spatial intensity on habitat, season, distance to roadkill and route location. We found that roadkill carcasses were a strong predictor of raven presence along road networks. The effect of roadkill was amplified on roads on the Bass Strait islands, where roadside carrion was a predictor of raven presence across the entire year. In contrast, ravens were more often associated with roadkill on Tasmanian mainland roads in the autumn, when other resources were low. This suggests that in the absence of competing mammalian scavengers, ravens choose to feed on roadside carrion throughout the year, even in seasons when other resources are available. This lack of competition could be disproportionately benefiting forest ravens, leading to augmented raven populations and changes to the vertebrate community structure. Our study provides evidence that scavengers modify their behaviour in response to reduced scavenger species diversity, potentially triggering trophic shifts and highlighting the importance of conserving or reintroducing carnivores within ecosystems.
Assuntos
Carnívoros , Ecossistema , Animais , Teorema de Bayes , Cadeia Alimentar , Ilhas , Estações do AnoRESUMO
Soil degradation is a worsening global phenomenon driven by socio-economic pressures, poor land management practices and climate change. A deterioration of soil structure at timescales ranging from seconds to centuries is implicated in most forms of soil degradation including the depletion of nutrients and organic matter, erosion and compaction. New soil-crop models that could account for soil structure dynamics at decadal to centennial timescales would provide insights into the relative importance of the various underlying physical (e.g. tillage, traffic compaction, swell/shrink and freeze/thaw) and biological (e.g. plant root growth, soil microbial and faunal activity) mechanisms, their impacts on soil hydrological processes and plant growth, as well as the relevant timescales of soil degradation and recovery. However, the development of such a model remains a challenge due to the enormous complexity of the interactions in the soil-plant system. In this paper, we focus on the impacts of biological processes on soil structure dynamics, especially the growth of plant roots and the activity of soil fauna and microorganisms. We first define what we mean by soil structure and then review current understanding of how these biological agents impact soil structure. We then develop a new framework for modelling soil structure dynamics, which is designed to be compatible with soil-crop models that operate at the soil profile scale and for long temporal scales (i.e. decades, centuries). We illustrate the modelling concept with a case study on the role of root growth and earthworm bioturbation in restoring the structure of a severely compacted soil.
Assuntos
Oligoquetos , Solo , Agricultura , Animais , PlantasRESUMO
BACKGROUND: Antenatal care (ANC), facility delivery and postnatal care (PNC) are proven to reduce maternal and child mortality and morbidity in high-burden settings. However, few pregnant rural women use these services sufficiently. This study aims to assess the impact, cost-effectiveness and scalability of conditional cash transfers to promote increased contact between pregnant women or women who have recently given birth and the formal healthcare system in Kenya. METHODS: The intervention tested is a conditional cash transfer to women for ANC health visits, a facility birth and PNC visits until their newborn baby reaches 1 year of age. The study is a cluster randomized controlled trial in Siaya County, Kenya. The trial clusters are 48 randomly selected public primary health facilities, 24 of which are in the intervention arm of the study and 24 in the control arm. The unit of randomization is the health facility. A target sample of 7200 study participants comprises pregnant women identified and recruited at their first ANC visit over a 12-month recruitment period and their subsequent newborns. All pregnant women attending one of the selected trial facilities for their first ANC visit during the recruitment period are eligible for the trial and invited to participate. Enrolled mothers are followed up at all health visits during their pregnancy, at facility delivery and for a number of visits after delivery. They are also contacted at three additional time points after enrolling in the study: 5-10days after enrolment, 6 months after the expected delivery date and 12 27 months after birth. If they have not delivered in a facility, there is an additional follow-up 2 wees after the expected due date. The impact of the conditional cash transfers on maternal healthcare services and utilization will be measured by the trial's primary outcomes: the proportion of all eligible ANC visits made during pregnancy, delivery at a health facility, the proportion of all eligible PNC visits attended, the proportion of referrals attended during the pregnancy and the postnatal period, and the proportion of eligible child immunization appointments attended. Secondary outcomes include; health screening and infection control, live birth, maternal and child survival 48 h after delivery, exclusive breastfeeding, post-partum contraceptive use and maternal and newborn morbidity. Data sources for the measurement of outcomes include routine health records, an electronic card-reader system and telephone surveys and focus group discussions. A full economic evaluation will be conducted to assess the cost of delivery and cost effectiveness of the intervention and the benefit incidence and equity impact of trial activities and outcomes. DISCUSSION: This trial will contribute to evidence on the effectiveness and cost-effectiveness of conditional cash transfers in facilitating health visits and promoting maternal and child health in rural Kenya and in other comparable contexts. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03021070 . Registered on 13 January 2017.
Assuntos
Continuidade da Assistência ao Paciente/economia , Apoio Financeiro , Financiamento Pessoal/economia , Custos de Cuidados de Saúde , Cooperação do Paciente , Assistência Perinatal/economia , Serviços de Saúde Rural/economia , Análise Custo-Benefício , Feminino , Humanos , Lactente , Recém-Nascido , Quênia , Motivação , Assistência Perinatal/métodos , Pobreza/economia , Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de TempoRESUMO
We introduce RadiO, a prototype application ontology for the support of electronic radiology reporting. This application ontology is implemented in Protégé and comprises three layers: 1. a radiology report layer, capturing observations made on patient examinations through the use of a controlled vocabulary of the radiographic imaging domain (RadLex), 2. an imaging domain ontology, representing knowledge about image entities and their image features, and 3. a reference ontology for anatomy (Foundational Model of Anatomy), representing canonical anatomical knowledge. The aim of this prototype is to support the identification of image features of image entities and their use in diagnostic interpretations, as well as to provide a basis for structured reporting applications in the domain of medical imaging.
Assuntos
Radiografia/classificação , Vocabulário Controlado , Humanos , SoftwareRESUMO
Medical ontologies like GALEN, the FMA or SNOMED represent a kind of "100% certain" medical knowledge which is not inherent to all medical sub-domains. Clinical radiology uses computerized imaging techniques to make the human body visible and interprets the imaging findings in a clinical context delivering a textual report. For clinical radiology few standardized vocabularies are available. We examined the definitions given in the glossary of terms for thoracic radiology published by the Fleischner Society. We further classified these terms with regard to their definitions in terms of (a) describing visible structures on the image itself, (b) referring to ontological entities of the body (anatomical or pathological), and (c) terms imposing knowledge on structures visible on the image, epistemologically representing ontological entities of the body. Each ontological/epistemological definition was rated on a scale of vague/weak-sound/strong and put in context with the evaluation comments for the use of the terms given in the glossary itself. The result of this distinction shows that clinical radiology uses many terms referring to ontological entities valid for representation in a medical ontology. However, many epistemological terms exist in the terminology which impose epistemological knowledge on ontological entities. The analysis of the evaluation comments reveals that terms classified as sound (ontologically) and strong (epistemologically) are evaluated higher than terms bearing vague or weak definitions. On the basis of this, we argue that the distinction between ontological and epistemological definitions is necessary in order to construct epistemologically-sensitive application ontologies for medical sub-domains, like clinical radiology, where knowledge is fragmented in terms of description, inferred from a description, concluded on the basis of imaging, or other additional information with varying degrees of certainty.