Conservation science for common ground: developing the necessary tools to manage livestock grazing pressure in Bale Mountains National Park, Ethiopia

One of the greatest proximate threats facing biodiversity is habitat change as a result of the combined effects of agricultural development and livestock grazing. Extensive livestock systems are increasingly competing with wildlife for access to land and natural resources in African rangelands. Ethiopia has the highest numbers of livestock in Africa with most livestock production taking place in highland systems. The Bale Mountains contain the largest extent of afroalpine habitat in Africa and are the most important conservation area in Ethiopia as one of thirty-four Conservation International Biodiversity Hotspots. The Bale Mountains National Park was established forty years ago to protect the endemic, and rodent-specialist Ethiopian wolf (Canis simensis) and the afroalpine habitats upon which they depend. I use a 21 year time-series of livestock counts in the park to detect changes in the Oromo traditional livestock production system or godantu. I show that a seasonal transhumant livestock production regime, akin to godantu, only appears to persist in the Web valley today and I also find some evidence that the type of livestock is changing with smaller stock, such as sheep and goats, being more frequently kept. Despite reportedly growing numbers of households in the Web valley, I do not detect an overall increase in livestock numbers, suggesting that the area may have reached its carrying capacity in terms of livestock. In contrast, the number of livestock on the Sanetti Plateau increased over the monitoring period, including the remote and inhospitable western section of the plateau. Furthermore, I detect an increase in the risk of contact and disease transmission between Ethiopian wolves and free-roaming dogs in wolf optimal habitats. I subsequently estimate, through the use of transects, the densities of livestock in the Web valley, Morebawa and Sanetti and calculate the ratio of observed to maximum sustainable livestock density (based on rainfall and vegetation productivity). The conservative results suggest that the Web valley and Morebawa are overstocked given the rangeland predicted productivity for those areas, and that the problem of overstocking is at its worst during the dry season. I then establish critical relationships between vegetation conditions, livestock grazing pressure and rodent populations (Tachyoryctes macrocephalus, Lophuromys melanonyx and Arvicanthis blicki) in the afroalpine, under both natural and controlled experimental conditions. Rodent biomass declines as the livestock index increases along a natural grazing gradient, but rodents‟ body condition, use of the habitat or breeding ecology and most vegetation variables measured do not significantly vary across the livestock grazing gradient. Rodent populations do respond to the experimental removal of livestock inside exclosures, although this response is site and species-specific, and I find some evidence that these responses are concurrent with changes in the vegetation. Grazed plots have higher plant species richness and diversity compared to the exclosure sites which harbour reduced bareground cover and taller vegetation. Differences among rodent species in their responses to grazing may be mediated by interaction between the direct effects of grazing on habitat quality and species-specific habitat requirements, although the specific mechanism of this interaction could not be tested. Livestock may negatively affect rodents by increasing their predation risk (through removing vegetation cover), by reducing the soil suitability for maintaining burrow systems (through trampling) or, less likely, by competing for food resources. A series of simple dynamic food chain models are developed to explore the interactions between Ethiopian wolves, rodents and vegetation and how they may be affected by increasing levels of livestock grazing. I also explore how predictions made about these trophic dynamics are affected by the type of functional response linking the different levels. The models suggest that the pastures of the Web valley and Morebawa are likely to be incapable of maintaining wolves at current livestock densities, while the Sanetti plateau may be able to sustain only slight increases in livestock density before tipping into a trophic configuration unable to sustain wolves. This model is a first step in assessing the seriousness of conflict between pastoralists and wildlife in BMNP. Resource selection functions are developed and validated for cattle and sheep/goats grazing in the Bale afroalpine in an attempt to understand some of the drivers behind the heterogeneous use of the landscape by livestock. Habitat use by livestock is focused on lower-lying pastures in the vicinity of water sources (rivers or mineral springs). Only cattle strongly select for/against particular vegetation types. The probability of habitat use is also linked to the distance from the nearest villages. The models developed highlight a strong association between livestock use and rodent biomass in Morebawa and Eastern Sanetti, suggesting that livestock grazing poses a threat to Ethiopian wolves‟ persistence in marginal habitats in which rodent availability is already limited. Furthermore, the concentration of livestock around water sources has serious implications for the degradation of the park‟s hydrological system and the livelihoods and food security of the millions of people living in the dependent lowlands. Integrating research and practice is a fundamental challenge for conservation. I discuss how the methodological tools developed and the insights gained into the dynamics of the afroalpine system can contribute to the management of livestock grazing pressure in Bale Mountains National Park and highlight gaps in the knowledge of the afroalpine ecosystem where more research is needed

Editorial : Women in veterinary epidemiology and economics

While the number of women graduating from veterinary schools has increased globally over the last few decades, this has not translated into reduced gender bias and inequity in academia and veterinary science research (1). Gender-based discrimination starts at university where women veterinary students are pushed toward “women-majority fields” (e.g., small animal medicine) (2) or where they face discrimination during animal husbandry placements (3). Following graduation, there is clear evidence that gender differences persist in pay and attainment of senior and leadership positions (4). Women's advancement and standing in academic veterinary medicine may in part be influenced by pronounced gender differences in the authorship of veterinary research articles. Women are less likely to be a senior author on a research paper and they are significantly underrepresented in some fields such as surgical and production animal research (5). Gender disparity in professional leadership roles like editorial boards—the median publisher in veterinary sciences had 27.5% editorships belonging to women (6)—can summate by impairing peer recognition and academic advancement.Instituto de VirologíaFil: Capozzo, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; ArgentinaFil: Capozzo, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vial, Flavie. Animal and Plant Health Agency; Reino Unid

Value of evidence from syndromic surveillance with delayed reporting

ObjectiveWe apply an empirical Bayesian framework to perform changepoint analysis on multiple cattle mortality data streams, accountingfor delayed reporting of syndromes.IntroductionTaking into account reporting delays in surveillance systems isnot methodologically trivial. Consequently, most use the date of thereception of data, rather than the (often unknown) date of the healthevent itself. The main drawback of this approach is the resultingreduction in sensitivity and specificity1. Combining syndromicdata from multiple data streams (most health events may leave a“signature” in multiple data sources) may be performed in a Bayesianframework where the result is presented in the form of a posteriorprobability for a disease2.MethodsWe used a historical national database on Swiss cattle mortality tomodel daily baseline counts of two syndromic time series3. Reportingdelay was defined as the number of days between reported occurrenceand reporting date. The cumulative probability distribution of theestimated reporting delays was used to calculate for each day theproportion of cases that were reported either on the same day or witha delay of 1 to 14 days.We evaluated outbreak detection performance under threescenarios: (A) delayed data reporting occurs but is not accountedfor; (B) delayed data reporting occurs and is accounted for; and (C)absence of delayed data reporting (i.e. an ideal system). Outputsare presented as the value of evidence (V) in favour of an ongoingoutbreak accumulated overnpoints in time (30 days in this case).At each timet, V is defined as the ratio between the posterior andprior odds for H1versus H0:[insert equation 1 here]Using sensitivity, time to detection and in-control run length,performance of the (V-based) system on large and small non-specificoutbreaks was measured.ResultsThe evolution of V based on the information available on the 1st,5th and 10th day after the onset of an outbreak can be visualised inFig. 1. After 5 days, V shows evidence in favour of an outbreak forboth syndromes combined, as well as for on-farm deaths alone, only inthe “Delay aware” and “No delay” scenarios. The development of Vfor the perinatal deaths alone highlights the importance of consideringmultiple syndromic data streams for outbreak detection, as it speaksin favour of an outbreak at a later stage than on-farm deaths alone orboth syndromes combined.ConclusionsOur empirical Bayes approach is an attractive alternative tomultivariate CUSUM algorithms offering a logical approach toweighting variables and incorporating additional information such asdelayed reporting, and a performance on a comparable level to anideal (no delay) system. Outbreaks are detected earlier and with onlya marginal loss of specificity compared to a system where reportingdelay is present but unaccounted for.We also found that the accumulation of evidence from severaldays resulted in a significantly better outbreak detection timeliness,for a given specificity; or a similar timeliness, but higher specificity,compared to an algorithm4that only looks for days with unusual highnumber of counts.Fig. 1: Evolution of V over three time points (t) for the three scenarios.Outbreak starts at t=651. Number of observed perinatal (circle) and on-farmdeaths (cross), V for both (solid grey) and individual syndromes (dotted greyand black respectively), prior probability that an outbreak is ongoing (greydashed) and posterior probability that an outbreak is ongoing given theevidence (black dashed). Horizontal grey solid line shows V=1

Data-fed, needs-driven: Designing analytical workflows fit for disease surveillance

Syndromic surveillance has been an important driver for the incorporation of “big data analytics” into animal disease surveillance systems over the past decade. As the range of data sources to which automated data digitalization can be applied continues to grow, we discuss how to move beyond questions around the means to handle volume, variety and velocity, so as to ensure that the information generated is fit for disease surveillance purposes. We make the case that the value of data-driven surveillance depends on a “needs-driven” design approach to data digitalization and information delivery and highlight some of the current challenges and research frontiers in syndromic surveillance

Long-term effect of a GnRH-based immunocontraceptive on feral cattle in Hong Kong

Increasing human-wildlife conflicts worldwide are driving the need for multiple solutions to reducing “problem” wildlife and their impacts. Fertility control is advocated as a non-lethal tool to manage free-living wildlife and in particular to control iconic species. Injectable immunocontraceptives, such as GonaCon, stimulate the immune system to produce antibodies against the gonadotrophin-releasing hormone (GnRH), which in turn affects the release of reproductive hormones in mammals. Feral cattle (Bos indicus or Bos taurus) in Hong Kong are an iconic species whose numbers and impacts on human activities have increased over the last decade. Previous studies have proven that a primer vaccination and booster dose of GonaCon in female cattle are safe and effective in reducing pregnancy levels one year post-treatment. The aims of this project were 1. to evaluate the longevity of the effect of GonaCon in feral cattle up to four years post-vaccination; and 2. to assess if a second booster dose of GonaCon, administered at either two or four years post-vaccination, extends the contraceptive effect in this species. Vaccination with Gona- Con, administered as a primer and booster dose, was effective in causing significant infertility in free-living cattle for at least three years post-vaccination, with the percentage of pregnant animals in the vaccinated group decreasing from 76% at vaccination to 35%, 19% and 7% in years 2, 3 and 4 post-vaccination, compared with 67% at vaccination to 50%, 57% and 14% respectively in the control group. A second booster dose of GonaCon administered either 2 or 4 years after vaccination rendered 100% of the Treated cattle infertile for at least another year. These results suggested that vaccination with GonaCon can reduce feral cattle population growth and that a second booster dose can extend the longevity of the contraceptive effect

Long-term effect of a GnRH-based immunocontraceptive on feral cattle in Hong Kong

Increasing human-wildlife conflicts worldwide are driving the need for multiple solutions to reducing “problem” wildlife and their impacts. Fertility control is advocated as a non-lethal tool to manage free-living wildlife and in particular to control iconic species. Injectable immunocontraceptives, such as GonaCon, stimulate the immune system to produce antibodies against the gonadotrophin-releasing hormone (GnRH), which in turn affects the release of reproductive hormones in mammals. Feral cattle (Bos indicus or Bos taurus) in Hong Kong are an iconic species whose numbers and impacts on human activities have increased over the last decade. Previous studies have proven that a primer vaccination and booster dose of GonaCon in female cattle are safe and effective in reducing pregnancy levels one year post-treatment. The aims of this project were 1. to evaluate the longevity of the effect of GonaCon in feral cattle up to four years post-vaccination; and 2. to assess if a second booster dose of GonaCon, administered at either two or four years post-vaccination, extends the contraceptive effect in this species. Vaccination with Gona- Con, administered as a primer and booster dose, was effective in causing significant infertility in free-living cattle for at least three years post-vaccination, with the percentage of pregnant animals in the vaccinated group decreasing from 76% at vaccination to 35%, 19% and 7% in years 2, 3 and 4 post-vaccination, compared with 67% at vaccination to 50%, 57% and 14% respectively in the control group. A second booster dose of GonaCon administered either 2 or 4 years after vaccination rendered 100% of the Treated cattle infertile for at least another year. These results suggested that vaccination with GonaCon can reduce feral cattle population growth and that a second booster dose can extend the longevity of the contraceptive effect