Livestock Density Research Articles

Responses of forest structure, functions, and biodiversity to livestock disturbances: A global meta-analysis.

Habitat degradation and land-use change driven by the livestock sector are among the major causes of global biodiversity loss. Forests are crucial in maintaining biodiversity and mitigating climate change. Apart from continuing deforestation, forests also face increasing pressure from livestock grazing in the system, which is less understood compared to grasslands. Through a meta-analysis of 156 articles with 1936 data entries, this study assesses the effect of livestock on forest biodiversity, structure, and functions, varying with livestock types, livestock density, grazing history, and climatic factors. Our results show that livestock overall had a negative impact on the forest structure and functions, reduced species abundance but increased richness. Medium and large mammals, plant communities, and soil were more negatively affected compared to other groups such as birds and invertebrates. Livestock also influenced the role of forests in mitigating climate change. They changed forest carbon stock by reducing plant biomass; however, they did not significantly impact the soil carbon stock or soil greenhouse gas emissions. Ecosystem attributes were more affected in warmer and drier regions and by single species grazing than the mixed grazing. Past livestock grazing history moderates the impacts of livestock, with the strongest negative effect occurred with a history of 1-5years. Nonetheless, livestock activities also had a positive impact on forest management, such as reducing forest flammability. Our results also indicate the lack of studies on how higher trophic levels respond to livestock disturbances and how grazing intensity moderates the effect, which includes grazing duration and livestock density. The complex responses of forests to livestock in different conditions call for more adaptive management depending on the conservation targets and evolution history.

Analysis of conflicts with wild carnivores in the Humid Chaco, Argentina

Interactions between humans and carnivores tend to be conflictual, especially due to predation on domestic animals. As certain landscape characteristics predispose the occurrence of carnivore attacks, spatial modelling of predation events can be particularly useful when developing management plans. In this study we determined the incidence of predation on the mortality of domestic animals by interviewing local inhabitants. In addition, we identified the spatial variables that explain the distribution of the conflicts and we created a two–scale model based on the Maxent algorithm. The results showed that Puma concolor (41.2 %) and the foxes Lycalopex gymnocercus and Cerdocyon thous (33.3 %) were the most conflictive species. Predation accounted for only 5.6 % of the causes of domestic animal mortality. The distribution models showed that the most probable variables for predicting conflicts were the distance from the roads, livestock density and the proportion of anthropized areas. High–risk areas represented 28 % of the study area and were distributed in broad patches around the protected areas and in the eastern sector of the area.

Increasing risks for emerging infectious diseases within a rapidly changing High Asia

The cold and arid mountains and plateaus of High Asia, inhabited by a relatively sparse human population, a high density of livestock, and wildlife such as the iconic snow leopard Panthera uncia, are usually considered low risk for disease outbreaks. However, based on current knowledge about drivers of disease emergence, we show that High Asia is rapidly developing conditions that favor increased emergence of infectious diseases and zoonoses. This is because of the existing prevalence of potentially serious pathogens in the system; intensifying environmental degradation; rapid changes in local ecological, socio-ecological, and socio-economic factors; and global risk intensifiers such as climate change and globalization. To better understand and manage the risks posed by diseases to humans, livestock, and wildlife, there is an urgent need for establishing a disease surveillance system and improving human and animal health care. Public health must be integrated with conservation programs, more ecologically sustainable development efforts and long-term disease surveillance.

An assessment of nitrogen loading and biogas production from Italian livestock: A multilevel and spatial analysis

The management of livestock effluents to reduce their environmental impact requires knowledge of not only the quantity produced but also the availability of agricultural areas, the condition of contiguous areas and the opportunity to exploit the energetic value of effluents. In this paper, a description of the Italian livestock system is provided, with a focus on its consequences in terms of the nitrogen load and biogas potential produced by the management of effluents. The analysis considered 9,589 million animal units (AU) and indicated an overall nitrogen production of 508 × 106 tons, while the methane potential can reach 1,764 × 106 m3, equal to 6.1% of the national electric energy consumption. To organize effective collection and treatment of effluents, their spatial distribution was investigated using spatial statistical tools: Moran's index and local indicator of spatial association (LISA). Moran's index analysis showed that animal units (Moran's I = 0.63), nitrogen load per hectare of UAA (Moran's I = 0.35) and methane potential per square kilometre (Moran's I = 0.58) were significantly clustered. Using LISA, a series of maps and scatter plots were elaborated to identify clusters of high nitrogen loads and high methane production. The analysis showed that 764 municipalities are included in clusters of a high density of livestock, and 635 municipalities resulted in clusters of high methane potential. The results demonstrated the robustness of these instruments to evaluate the presence of nitrogen/biogas production clusters and the possibility of combining the treatment of nitrogen and the production of biogas from animal effluents. Analysing the distribution of livestock and the 2,723 biogas plants operating in Italy, the study found that 75.0% of the bioresources are available 5 km from the nearest biogas plant, 89.9% at 10 km, 94.7% at 15 km and 97.4% at 20 km.

Land use influence on distribution and abundance of herbivores in Samburu-Laikipia, Kenya

The distribution and abundance of different wildlife herbivores was studied in Samburu-Laikipia landscape. The study sites included; Mpala and Oljogi, both commercial ranches in Laikipia district; Oldonyiro and Kipsing community areas in Isiolo district; West Gate Conservancy, Ngaroni Community area, Kalama Community area and Sessia-Barsalinga Community area in Samburu district; and Buffalo Spring National Reserve and Samburu National Reserve both protected areas in the landscape. The objectives of the study were: 1) Determine the influence of different land use on seasonal abundances and distribution wildlife species and 2) Examine the influence of livestock, human settlements and water on wildlife species in Samburu-Laikipia landscape. Distance sampling was used to estimate wildlife, livestock and bomas densities. Distance to nearest water was projected from GPS coordinates for both wildlife and livestock sighting using ARCGIS. Our analysis showed non-uniform distributions of wildlife groups across the Samburu-Laikipia ecosystem largely driven by seasonal rainfall patterns and land use types. Like predicted, most wildlife groups occurred in higher abundances on protected areas, Laikipia commercial ranches and community conservancies unlike in community grazing areas in both dry and wet season. However, large grazers increased substantially in community grazing areas over the wet season when livestock grazing was heavy, stimulating growth of short annuals plants of high-quality nutrients. Human activities had negative influences on all wildlife groups. Our findings indicate that the type of land -use influenced herbivore distribution and abundance in Samburu-Laikipia landscape. This suggests that human activities, including pastoralism, in conjunction with season rainfall patterns and land-use shape herbivore distribution and abundance in the area. Conservation strategies for successfully increasing survival of wildlife therefore, requires maintenance of a mixture of land-use types with well controlled and sustainable development.

Robustness to import declines of three types of European farming systems assessed with a dynamic nitrogen flow model

CONTEXTAgriculture in Western Europe is predominantly input-intensive (fertilisers, water, fuel, pesticides) and relies on feed imports. As a result, it is dependent on oil, which may start to decline in production in the 2020s, thus exposing the agricultural sector to potential economic stress, including increased input prices and decreased farmer purchase capacities. Therefore, it is necessary to assess the capacity of European farming systems (FS) to maintain production levels despite a decline in oil production (i.e., robustness). OBJECTIVEWe aimed to model and compare the time variations in the animal- and crop-sourced production of three French FS under three scenarios of decreased availability of feed and synthetic fertiliser imports. METHODSWe developed a FS-scale dynamic model that considers nitrogen flows between livestock, plant, and soil compartments. Plant production is a function of soil mineral nitrogen levels, and livestock numbers depend on feed availability. The three FS are characterised by different crop-grassland-livestock balances: (i) field crop (Plateau Picard), (ii) intensive monogastric (Bretagne Centrale), and (iii) extensive ruminant (Bocage Bourbonnais). The three scenarios consist of different combinations of synthetic nitrogen fertilisers and feed import availability declines until 2050: a decrease in synthetic fertilisers only (Synth-), a decrease in feed imports (Feed-), and a decrease in both external inputs (Synth-Feed-). RESULTS AND CONCLUSIONSThe first two scenarios highlight the positive role of livestock effluents and permanent grasslands on the robustness of food production. In the Synth-Feed- scenario, the extensive ruminant FS exhibits robustness (no decline in food production) for 13 years, whereas the field crop FS exhibits robustness for 4 years. In contrast, the intensive monogastric FS shows decreased food production within the first year. The difference between the two crop-livestock FS can be explained by livestock density, herd composition but also plant cover composition. In the long term, all three FS show a decrease in food production between 45 and 60%. SIGNIFICANCEOur modelling work shed some light on the role of ruminants and permanent grasslands in making FS more robust to decreases in synthetic fertiliser and feed import availability, increasing the time without production decline after the beginning of the perturbation. For longer-time resilience, configurational changes are still necessary, however a greater robustness gives more time to implement them, therefore facilitating adaptation and transformation. Our model paves the way to the study of resilience of FS from the point of view of their crop-grassland-livestock configuration and their dependence on external inputs.

An integrated modelling approach to derive the grey water footprint of veterinary antibiotics

Water pollution by veterinary antibiotics (VAs) resulting from livestock production is associated with severe environmental and human health risks. While upward trends in global animal product consumption signal that these risks might exacerbate toward the future, VA related water pollution is currently insufficiently understood. To increase this understanding, the present research assesses processes influencing VA pollution from VA administration to their discharge into freshwater bodies, using an integrated modelling approach (IMA). For the VAs amoxicillin, doxycycline, oxytetracycline, sulfamethazine, and tetracycline we estimate loads administered to livestock, excretion, degradation during manure storage, fate in soil and transport to surface water. Fate and transport are modelled using the VA transport model (VANTOM), which is fed with estimates from the Pan-European Soil Erosion Risk Assessment (PESERA). The grey water footprint (GWF) is used to indicate the severity of water pollution in volumetric terms by combining VA loads and predicted no effect concentrations. We apply our approach to the German-Dutch Vecht river catchment, which is characterized by high livestock densities. Results show a VA mass load decrease larger than 99% for all substances under investigation, from their administration to surface water emission. Due to metabolization in the body, degradation during manure storage and degradation in soil, VA loads are reduced by 45%, 80% and 90% on average, respectively. While amoxicillin and sulfamethazine dissipate quickly after field application, significant fractions of doxycycline, oxytetracycline and tetracycline accumulate in the soil. The overall Vecht catchment's GWF is estimated at 250,000 m3 yr−1, resulting from doxycycline (81% and 19% contribution from the German and Dutch catchment part respectively). Uncertainty ranges of several orders of magnitude, as well as several remaining limitations to the presented IMA, underscore the importance to further develop and refine the approach.

Towards a flood vulnerability assessment of watershed using integration of decision-making trial and evaluation laboratory, analytical network process, and fuzzy theories.

Among natural disasters, flood is increasingly recognized as a serious worldwide concern that causes the most damages in parts of agriculture, fishery, housing, and infrastructure and strongly affects economic and social activities. Universally, there is a requirement to increase our conception of flood vulnerability and to outstretch methods and tools to assess it. Spatial analysis of flood vulnerability is part of non-structural measures to prevent and reduce flood destructive effects. Hence, the current study proposes a methodology for assessing the flood vulnerability in the area of watershed in a severely flooded area of Iran (i.e., Kashkan Watershed). First interdependency analysis among criteria (including population density (PD), livestock density (LD), percentage of farmers and ranchers (PFR), distance to industrial and mining areas (DTIM), distance to tourist and cultural heritage areas (DTTCH), land use, distance to residential areas (DTRe), distance to road (DTR), and distance to stream (DTS)) was conducted using the decision-making trial and evaluation laboratory (DEMATEL) method. Hence, the cause and effect factors and their interaction levels in the whole network were investigated. Then, using the interdependency relationships among criteria, a network structure from flood vulnerability factors to determine their importance of factors was constructed, and the analytical network process (ANP) was applied. Finally, with the aim to overcome ambiguity, reduce uncertainty, and keep the data variability, an appropriate fuzzy membership function was applied to each layer by analyzing the relationship of each layer with flood vulnerability. Importance analysis indicated that land use (0.197), DTS (0.181), PD (0.180), DTRe (0.140), and DTR (0.138) were the most important variables. The flood vulnerability map produced by the integrated method of DEMATEL-ANP-fuzzy showed that about 19.2% of the region has a high to very high flood vulnerability.

Spatial analysis of water quality and income in Europe

The purpose of this study is to empirically investigate the environmental Kuznets curve (EKC) relationship between water quality and income within the European Union, considering spatial interdependences across countries. To this end, we apply a spatial econometrics framework using panel data, at the national level, for twenty EU countries across seventeen years, 1998 to 2014. Furthermore, we account for the role of human and livestock population size, institutional quality and economic openness for water quality. Results show that a significant EKC relationship is seen with an inverted N -shaped relationship between income and water quality. Water quality is decreasing in income for low income levels, increasing in income when GDP per capita for medium income levels, and deteriorating for high income levels. Eight out of twenty countries have income levels associated with a declining water quality. Spatial spillovers between countries are significant. Higher livestock density levels are associated with lower levels of water quality, while institutional quality and openness to trade are positively associated with water quality. • We study the linkage between water quality and income in 20 EU countries. • We use spatial econometrics to account for spillovers between countries. • Results show an inverted N-shape relationship between income and water quality. • 8 out of 20 countries have income levels associated with deteriorating water quality. • Improved governance and economic openness positively affect water quality.

Antimicrobial Resistance Profiles of Coagulase-Negative Staphylococci in Community-Based Healthy Individuals in Germany.

Coagulase-negative staphylococci (CoNS) are common opportunistic pathogens, but also ubiquitous human and animal commensals. Infection-associated CoNS from healthcare environments are typically characterized by pronounced antimicrobial resistance (AMR) including both methicillin- and multidrug-resistant isolates. Less is known about AMR patterns of CoNS colonizing the general population. Here we report on AMR in commensal CoNS recovered from 117 non-hospitalized volunteers in a region of Germany with a high livestock density. Among the 69 individuals colonized with CoNS, 29 had reported contacts to either companion or farm animals. CoNS were selectively cultivated from nasal swabs, followed by species definition by 16S rDNA sequencing and routine antibiotic susceptibility testing. Isolates displaying phenotypic AMR were further tested by PCR for presence of selected AMR genes. A total of 127 CoNS were isolated and Staphylococcus epidermidis (75%) was the most common CoNS species identified. Nine isolates (7%) were methicillin-resistant (MR) and carried the mecA gene, with seven individuals (10%) being colonized with at least one MR-CoNS isolate. While resistance against gentamicin, phenicols and spectinomycin was rare, high resistance rates were found against tetracycline (39%), erythromycin (33%) and fusidic acid (24%). In the majority of isolates, phenotypic resistance could be associated with corresponding AMR gene detection. Multidrug-resistance (MDR) was observed in 23% (29/127) of the isolates, with 33% (23/69) of the individuals being colonized with MDR-CoNS. The combined data suggest that MR- and MDR-CoNS are present in the community, with previous animal contact not significantly influencing the risk of becoming colonized with such isolates.

Gender-specific determinants of Zai technology use intensity for improved soil water management in the drylands of Upper Eastern Kenya

Degraded landscapes and soil water stress are long-standing problems to smallholder agriculture in the drylands. Despite the important roles of zai technology in restoring degraded landscapes and improving agricultural productivity, the technology is yet to be adopted to its fullest extent. This can be attributed to gender-linked disparities in agricultural technology utilization. The study, therefore, sought to determine gender-specific determinants of zai technology choice and use-intensity. A multistage sampling technique was employed in randomly selecting 133 female-headed households and 267 male-headed households in Tharaka South sub-county. Quantitative data were collected in a cross-sectional survey using an interviewer-administered questionnaire. Using sex-disaggregated data, Chi-square and t-test statistic were employed to test the statistical significance of dummy and mean value of continuous variables, respectively. Gender specific determinants of zai technology choice and use-intensity were determined using the Heckman-two-step econometric model. The results revealed that, more women farmers (44%) were using zai technology as compared to men (38%). Among women farmers, total cultivated land, access to animal-drawn farm implements, and group membership had an influence on zai technology choice. For men, total cultivated land, group membership and access to extension services positively influenced choice of zai technology. With regard to zai technology use-intensity, total land cultivated, livestock densities, group membership and frequency of trainings on soil and water management were important determinants among women farmers. For men, zai technology use-intensity was determined by total cultivated land and farmers’ perceptions on soil erosion. We recommend that, gender-sensitive farm-level policies oriented towards farmer socioeconomic profiles are important deliberations towards choice and intense application of soil and water conservation strategies such as the zai technology.

The study of the potential development of goat and sheep in North Labuhanbatu Regency to support North Sumatera Province as a producer of goat and sheep

North Labuhanbatu Regency is one of the districts in North Sumatera that has potential in the development of livestock. This research aims to find out the potential of agriculture and plantation waste as well as areas that can be used as a development area for goat and sheep livestock in North Labuhanbatu Regency. The type of research used is descriptive research to describe the potential of agriculture and plantation waste in determining the development area of goat and sheep livestock using LQ methods combined with livestock density, waste support index and capacity to increase ruminants livestock population. This research was conducted in North Labuhanbatu Regency in February–April 2020. The results showed that North Labuhanbatu Regency has development potential in supporting North Sumatra Province a producer of goat and sheep livestock. Regional strategy I namely Aek Natas Sub-District, Kualuh Hilir, Kualuh Leidong. Regional strategy group namely Na IX-X, Aek Kuo, Kualuh Selatan, Kualuh Hulu sub-districts. Group III strategy namely Marbau sub-district. Alternative strategies for utilizing agriculture and plantation waste in the development of goat and sheep livestock one of them is the integration system in order to use crop waste as a source of animal feed in North Labuhanbatu Regency.

Land-use change and the livestock revolution increase the risk of zoonotic coronavirus transmission from rhinolophid bats.

The extent to which humans facilitate zoonotic transmission of infectious diseases is unclear. Human encroachment into wildlife habitats as a consequence of expanding urbanization, cropland area and intensive animal farming is hypothesized to favour the emergence of zoonotic diseases. Here we analyse comprehensive, high-resolution datasets on forest cover, cropland distribution, livestock density, human population, human settlements, bat species' distribution and land-use changes in regions populated by Asian horseshoe bats (>28.5 million km2)-the species that most commonly carry severe acute respiratory syndrome (SARS)-related coronaviruses. We identify areas at risk of SARS-related coronavirus outbreaks, showing that areas in China populated by horseshoe bats exhibit higher forest fragmentation and concentrations of livestock and humans than other countries. Our findings indicate that human-livestock-wildlife interactions in China may form hotspots with the potential to increase SARS-related coronavirus transmission from animals to humans.

Risk and Environmental Factors Associated with the Presence of Canine Parvovirus Type 2 in Diarrheic Dogs from Thessaly, Central Greece.

Canine parvovirus type 2 (CPV-2) primarily infects dogs, which are the main host reservoir, causing severe gastrointestinal disease associated with immunosuppression. The present study was conducted in Thessaly, Greece and aimed to identify risk and environmental factors associated with CPV-2 infection in diarrheic dogs. Fecal samples were collected from 116 dogs presenting diarrhea and were tested by polymerase chain reaction (PCR) for the presence of CPV-2 DNA. Supplementary data regarding clinical symptoms, individual features, management factors and medical history were also gathered for each animal during clinical evaluation. Sixty-eight diarrheic dogs were found to be positive for the virus DNA in their feces. Statistical analysis revealed that CPV-2 DNA was less likely to be detected in senior dogs, while working dogs, namely hounds and shepherds, had higher odds to be positive for the virus. Livestock density and land uses, specifically the categories of discontinuous urban fabric and of human population density, were identified as significant environmental parameters associated with CPV-2 infection by using Geographical Information System (GIS) together with the Ecological Niche Model (ENM). This is the first description of the environmental variables associated with the presence of CPV-2 DNA in dogs’ feces in Greece.

Three decades of regulation of agricultural nitrogen losses: Experiences from the Danish Agricultural Monitoring Program

Excess nitrogen (N) losses from intensive agricultural production are a world-wide problem causing eutrophication in vulnerable aquatic ecosystems such as estuaries. Therefore, Denmark as one of the most intensively farmed countries in the world has enforced mandatory regulations on agricultural production since the late 1980s. We demonstrate the outcome of the regulations imposed on agriculture by analyzing decadal trends in nitrate (NO3−) concentrations and loads in streams using 29 years of detailed monitoring data and survey information on agricultural practices at field level from five intensively cultivated headwater catchments. The analysis includes the importance of four main drivers (climate, land use, agricultural practices, and biogeophysical properties of catchments), each divided into different factors that may influence stream NO3− loads during three subperiods defined by the time of introduction of different mitigation measures: i) 1990–1998, ii) 1999–2007, and iii) 2008–2018.Significant correlations with annual flow-weighted stream NO3− concentrations and/or loads were found for factors representing all of the four main drivers including precipitation, large scale climate fluctuations, runoff, previous year's runoff, baseflow index, number of annual frost days, agricultural area, livestock density, field N surplus, catch crop cover, manure storage capacity, method and time of manure spreading, and time of soil tillage.Changes in the four drivers were reflected by the load-runoff (L-Q) relationships for each of the three subperiods within each of the five headwater catchments. The five catchments experienced large but catchment-specific downward shifts in the L-Q relationship attributable to changes in land use and agricultural management within the catchments. The documented large downward shifts in NO3− loads demonstrated for the five catchments (30–52%) as a consequence of mandatory regulation over a period of nearly three decades are a unique example of how agriculture can reduce its environmental impact.

Factors affecting the spatial distribution and co‐occurrence of two sympatric mountain ungulates in southern Mongolia

AbstractCo‐occurrence of ungulates in multi‐species assemblages has fascinated ecologists because these species seemingly belong to the same guild – feeding on plants. Across large parts of the high mountains of Central Asia, ibex (Capra sibirica) and argali (Ovis ammon), both predominantly grazers, co‐occur at local and regional scales. However, little is known about the ecological and anthropogenic factors that influence their spatial distribution, co‐occurrence and habitat use. We examined factors affecting the distribution and co‐occurrence of these two sympatric species in Tost Tosonbumba Nature Reserve in southern Mongolia using an occupancy modeling approach. Specifically, we used single species occupancy models to examine the influence of road density, livestock density, terrain ruggedness and elevation on occupancy of these two species separately. We then assessed how these two species influence each other's distribution by using multi‐species occupancy models. The model‐averaged occupancy probabilities for ibex and argali were 0.64 ± 0.3 se and 0.44 ± 0.2 se, respectively. Terrain ruggedness positively influenced ibex distribution, while it negatively affected the occupancy of argali. We found limited evidence of relationship with factors associated with human disturbance. The species interaction factor, which indicates the level of co‐occurrence, suggested that ibex and argali occurred independent of each other ( = 0.72 ± 0.3 se). Together, our results imply that there was limited co‐occurrence between the two species and that this was largely driven by terrain ruggedness at the scale of the home range. These results suggest that topography plays an important role in enabling these two species to co‐occur at the regional scale.

Patterns of rabies cases in South Africa between 1993 and 2019, including the role of wildlife.

Rabies is a global viral zoonosis endemic to South Africa, resulting in fatal encephalitis in warm-blooded animals, including humans. The loss of human lives and economic losses in rural areas through loss of livestock are substantial. A review was conducted of all confirmed animal rabies cases in South Africa from 1993 to 2019, with a total of 11701 cases identified to species level to assess the role that wildlife plays in the epidemiology of rabies. A spatio-temporal cluster analysis using a discrete Poisson space-time probability model, accounting for underlying estimated dog and livestock densities, identified 13 significant clusters (p<.05). These included four long-term clusters lasting more than 8years in duration and seven short-term clusters lasting less than 2years, with the remaining two clusters being of intermediate length. Outside of these endemic clusters, wildlife outbreaks in the remainder of South Africa were often less than one and a half years in duration most likely due to the rapid decline of wildlife vectors, especially jackals associated with rabies infection. Domestic dogs accounted for 59.8% of cases, with domestic cats (3.2%), livestock (21.1%) and wildlife (15.8%) making up the remainder of the cases. Yellow mongoose (Cynictis penicillata) was the most frequently affected wildlife species, followed by bat-eared fox (Otocyon megalotis), black-backed jackal (Canis mesomelas), meerkat (Suricata suricatta) and aardwolf (Proteles cristatus). Rabies in wildlife species followed different spatial distributions: black-backed jackal cases were more common in the north-western parts of South Africa, yellow mongoose cases more frequent in central South Africa, and bat-eared fox and aardwolf cases were more frequent in southern and western South Africa. Clusters often spanned several provinces, showing the importance of coordinated rabies control campaigns across administrative boundaries, and high-risk areas were highlighted for rabies in South Africa.

A Large Spatial Survey of Colistin-Resistant Gene mcr-1-Carrying E. coli in Rivers across Taiwan.

Background: Colistin is one of the last-line antimicrobial agents against life-threatening infections. The distribution of the colistin resistance gene mcr-1 has been reported worldwide. However, most studies have focused on the distribution of mcr-1-positive bacteria in humans, animals, food, and sewage; few have focused on their distribution in natural environments. Method: We conducted a large spatial survey of mcr-1-positive Escherichia coli at 119 sites in 48 rivers, covering the entire island of Taiwan. We investigated the relationship between the livestock or poultry density in the surveyed riverine area and the number of mcr-1-positive E. coli in the river water. We then sequenced and characterized the isolated mcr-1-positive plasmids. Results: Seven mcr-1 positive E. coli were isolated from 5.9% of the sampling sites. The mcr-1-positive sites correlated with high chicken and pig stocking densities but not human population density or other river parameters. Four of the mcr-1-positive E. coli strains harbored epidemic IncX4 plasmids, and three of them exhibited identical sequences with a size of 33,309 bp. One of the plasmids contained identical 33,309 bp sequences but carried an additional 5711-bp transposon (Tn3 family). To our knowledge, this is the first demonstration that mcr-1-carrying IncX4 plasmids can contain an insertion of such transposons. All mcr-1-positive isolates belonged to phylogenetic group A and harbored few known virulence genes. Conclusion: This study showed a positive relationship between the number of mcr-1-positive sites and high livestock and poultry density. The sequencing analyses indicated that the epidemic plasmid in the mcr-1 isolates circulates not only in humans, animals, and food but also in the associated environments or natural habitats in Taiwan, suggesting that the surveillance of antibiotics-resistance genes for livestock or poultry farm quality control should include their associated environments.

Agricultural nutrient loading under alternative climate, societal and manure recycling scenarios

This paper introduces a framework for extending global climate and socioeconomic scenarios in order to study agricultural nutrient pollution on an individual catchment scale. Our framework builds on and extends Representative Concentration Pathways (RCPs) and Shared Socioeconomic Pathways (SSPs) at the spatial and temporal scales that are relevant for the drivers of animal husbandry, manure recycling and the application of inorganic fertilisers in crop production. Our case study area is the Aura river catchment in South-West Finland, which discharges into the heavily eutrophic Baltic Sea. The Aura river catchment has intensive agriculture — both livestock and crop production. Locally adjusted and interpreted climate and socioeconomic scenarios were used as inputs to a field-level economic optimisation in order to study how farmers might react to the changing markets and climate conditions under different SSPs. The results on economically optimal fertilisation levels were then used as inputs to the spatially and temporally explicit nutrient loading model (VEMALA). Alternative manure recycling strategies that matched with SSP narratives were studied as means to reduce the phosphorus (P) overfertilisation in areas with high livestock density. According to our simulations, on average the P loads increased by 18% during 2071–2100 from the current level and the variation in P loads between scenarios was large (from −14% to +50%). By contrast, the nitrogen (N) loads had decreased on average by −9% (with variation from −20% to +3%) by the end of the current century. Phosphorus loading was most sensitive to manure recycling strategies and the speed of climate change. Nitrogen loading was less sensitive to changes in climate and socioeconomic drivers.

Assessing agro-food system circularity using nutrient flows and budgets

Nutrient reuse and recycling is a key strategy towards more circular and sustainable food systems and depends on the specific conditions of the area under study, such as geography and the type of agricultural system. In this study we analysed nutrient flows and assessed the circularity of a livestock-dominated and export-oriented agro-food system at different system levels and spatial scales. We quantified the nitrogen (N), phosphorus (P) and potassium (K) flows and soil balances in the Belgian agro-food system at the sub-regional, regional and national scale, and assessed five P-based indicators that capture different aspects of circularity: total inputs, phosphorus use efficiency, share of reused to total input, recycling rate, and losses. We found that nutrient soil balances depend on the type of agricultural system: areas with intense livestock production accumulate up to 108 kgN/ha, 4.8 kgP/ha and 150 kgK/ha in their soil annually, whereas areas of mostly arable production have low N and K surpluses of <20 kg/ha and P deficits of < -10 kg/ha. We further found that Wallonia, the southern region of the country that is characterized by lower livestock densities and a partial reuse of sewage sludge, outperforms the Flemish region in the North in all five indicators. The food system in the whole of Belgium has a 34% phosphorus use efficiency rate and a 63% overall recycling rate, while 84% of the total inputs in agriculture are from secondary sources. Our results show that the type of production system is the most crucial determinant for circularity, and highlight the benefit of working at different levels and spatial scales to capture all aspects of circularity in agro-food systems.