Animal Density Research Articles

Material properties and broadband backscatter measurements of individual euphausiids from the California coastal ecosystem

During the 14–24 May 2019 leg of the NOAA juvenile rockfish survey, zooplankton and small nekton were sampled off the coast of Northern California using a midwater trawl. This talk will focus on three euphausiid species (E. pacifica, T. spinifera, N. difficilis) which were present in most catches. Krill morphology (size and shape) and animal density relative to seawater were measured for 175 live (or very recently expired) individuals. Roughly 150 individual krill were frozen and brought back to land for mass measurements. Soundspeed relative to seawater was measured for 15 mixed-species aggregations of krill. Broadband (38–73 and 130–210 kHz) and narrowband (38, 50, 70, 120, 150, and 200 kHz) backscatter measurements were made on 32 live (or very recently expired) individual krill. These empirical measurements were then compared to predictive backscatter measurements using scattering model parameters measured for those individuals (when available). Differences between predicted and measured backscatter were generally small, although there were individual krill where measurements at some frequencies varied significantly (i.e. more than 3dB). Understanding the variability in scattering model inputs among and within these species, and the accuracy of scattering model predictions provides context (i.e. uncertainty estimates) for acoustic measures (or indices) of krill biomass.

A serological screening for potential viral pathogens among semi-domesticated Eurasian tundra reindeer (Rangifer tarandus tarandus) in Finland

BackgroundReindeer herding and husbandry is a traditional and important livelihood in Fennoscandia, and about 200,000 semi-domesticated reindeer are herded in Finland. Climatic changes, leading to ice-locked winter pastures, and encroachment of pasture-land have led to changes in reindeer husbandry, increasing the extent of supplementary or full ration feeding, which has become very common in Finland. Keeping reindeer in corrals or gathering them at permanent feeding sites will increase nose-to-nose contact between animals and they may be exposed to poor hygienic conditions. This may impact the epidemiology of infectious diseases, such as viral infections. The aim of this study was to investigate Finnish semi-domesticated reindeer for exposure to viral pathogens. Blood samples were collected from 596 reindeer (358 calves, 238 adults) in 2015, from nine reindeer slaughterhouses, representing most of the reindeer herding regions in Finland. Plasma samples were investigated for antibodies against a selection of known and potential reindeer viral pathogens by using enzyme linked immunosorbent assays (ELISA).ResultsThe screening suggested that alphaherpesvirus and gammaherpesvirus (malignant catarrhal fever virus group; MCFV) were enzootic in the reindeer population, with a seroprevalence of 46.5% (range at slaughterhouse level 28.6–64.3%) and 29.0% (range 3.5–62.2%), respectively. Whereas the seroprevalence was significantly higher for alphaherpesvirus among adult reindeer (91.2%) as compared to calves (16.8%), no age difference was revealed for antibodies against gammaherpesvirus. For alphaherpesvirus, the seroprevalence in the northernmost region, having the highest animal density (animals/km2), was significantly higher (55.6%) as compared to the southernmost region (36.2%), whereas the seroprevalence pattern for gammaherpesvirus indicated the opposite, with 8.1% in the north and 50.0% in the south. Four reindeer (0.7%) had antibodies against Pestivirus, whereas no antibodies were detected against Bluetongue virus or Schmallenbergvirus.ConclusionsAlphaherpesvirus and gammaherpesvirus (MCFV) seems to be enzootic in the Finnish reindeer population, similar to other reindeer herds in Fennoscandia, whereas the exposure to Pestivirus was low compared to findings in Norway and Sweden. The ongoing changes in the reindeer herding industry necessitate knowledge on reindeer health and diseases that may impact animal welfare and health of reindeer as well as the economy of the reindeer herding industry.

Using cost‐effectiveness analysis to compare density‐estimation methods for large‐scale wildlife management

AbstractDensity estimates for animal populations often inform conservation and management decisions. Many methods to estimate animal density exist but deciding between competing alternatives traditionally has depended upon assessing multiple factors (e.g., precision, total cost, area sampled) independently and often in an ad hoc manner. Cost‐effectiveness analysis is a tool that economists use to decide objectively between competing alternatives. We extend cost‐effectiveness analysis to simultaneously integrate precision and per‐area cost of sampling when selecting between competing techniques used to estimate animal density both after a single application of a method and across several applications of capital equipment. Our extension allows for weighting of factors that may vary with the objectives and constraints of decision makers. We apply our extension of cost‐effectiveness analysis to a case study in which population density of white‐tailed deer (Odocoileus virginianus) was estimated in 3 large management units in Indiana, USA, using 3 competing distance‐sampling methods: fecal‐pellet, camera‐trap, and aerial sampling. The unweighted cost effectiveness of aerial sampling with color and infrared sensors was usually superior after a single application of each method and was always superior across several applications in differing landscapes. Pellet sampling was the most cost effective after a single application of each method in an agriculturally‐dominated management unit. Although camera sampling has increased in popularity, the cost effectiveness of camera sampling was poorer than the other 2 methods, even when allowing for potential future innovations to streamline data processing. Cost‐effectiveness analysis can be useful when selecting among competing methods for monitoring animal populations of conservation and management importance. The same principles used in our cost‐effectiveness analysis can be used to decide between competing alternatives related to any ecological monitoring in addition to density estimation.

A meta‐analysis of shrub density as a predictor of animal abundance

Facilitative interactions between shrub and animal species influence the structure and composition of communities. The benefits associated with woody shrub species can critically influence local animal populations, in particular. Here, we tested the relative importance of the density of shrub species on the local abundance of animal populations using a meta‐analysis. Full‐text review for shrub density, animal abundance or density and sampling effort, resulted in a total of 113 independent observations that reported both shrub density and animal abundance. A meta‐regression of shrub density on animal density with feeding functional group of the animal species as a moderator was used to test the predictive capacity of this simple vegetation measure on animal populations. Shrub density positively predicted animal abundance in these studies – particularly in deserts and grasslands. Shrub and woody plant density can thus be used as a potential rapid proxy for habitat in predicting local animal abundances. This method can support restoration and conservation of resident animal species in impacted ecosystems structured by woody shrubs globally.

Adaptive grazing and animal density implications for stocking rate and drought in northern mixed-grass prairie

Grazing management is critical for ruminant livestock enterprises affecting both animal performance and land sustainability. Intensification of grazing management is important for increasing food production, however, linear stocking rate models are not ideal in rangeland environments due to complexities such as drought. We conducted a study in a semiarid northern mixed-grass prairie in Wyoming, USA from 2017 to 2021. Grazing treatments were moderate rotational grazing (MRG; 4 heifers), ultra-high density rotational grazing (UHD; 33 cow-calf pairs), and no grazing (NG) organized in a randomized complete block design using 0.4 ha paddocks. Baseline vegetation was measured prior to grazing each year to determine grazing time available using a modified Robel pole coupled with forage biomass clippings. Planned and realized stocking rates were then calculated for all MRG and UHD treatments and potential stocking rates for NG and relativized to effective precipitation (March 1 to timing of sampling in mid-June). For the UHD treatment, cattle time in paddocks ranged from 0.29 to 1 d while for the MRG treatment, cattle time in paddocks ranged from 4.5 d to 12.5 d Effective precipitation ranged from 130 mm in 2020 to 251 mm in 2018 with a five year mean of 205.4 mm. Planned/potential stocking rate ranged from 1.40 to 5.17 Animal Unit Months per hectare (AUMs ha−1) and realized stocking rate ranged from 1.38 to 4.87 AUMs ha−1 across paddocks and years. Vegetation visual obstruction and stocking rate did not differ by treatment any of the years of the study (all p-values > 0.05) with the exception of 2020 when the NG treatment was higher than the MRG and UHD treatments (p < 0.05). Planned and realized stocking rates for both grazing treatments had highly correlated (both r2-values ≥ 0.80) and significant relationships (both p-values < 0.05) with effective precipitation. Five year mean planned or realized stocking rates did not differ by treatment. Accomplishing planned stocking rates proved to be difficult for the UHD grazing scheme that requires rapid moves as indicated by the broader range of ΔAUMs ha−1 (Planned – Realized) in that treatment compared to the MRG treatment. The effect of precipitation on stocking rates, and specifically relative to potential stocking in the NG treatment, was most influential during the significant deficit year but was non-existent during average years or surplus years. Using annual visual obstruction readings (VOR) to adapt stocking rates may be useful for more intense grazing management.

Data analysis supports monitoring and surveillance of goat health and welfare in the Netherlands

Monitoring and surveillance systems have an increasingly important role in contemporary society ensuring high levels of animal health and welfare, securing export positions, and protecting public health by ensuring animal health and product safety. In the Netherlands, a voluntary monitoring and surveillance system is in place since 2003 to provide a broad overview of livestock trends in addition to disease-specific surveillance systems, including insight into the occurrence and prevalence of new and emerging non-notifiable diseases and disorders. Being a major surveillance component of this monitoring and surveillance system for small ruminant health in the Netherlands, an annual data analysis on routine census data is performed to retrospectively monitor trends and developments regarding goat health and welfare. This paper aims to describe the process of the data analysis on goat farms in the Netherlands in 2020 and subsequent results are discussed. The data analysis provides key monitoring indicators such as animal and farm density, mortality, animal movements, and numbers and origin of imported small ruminants. Trends were analysed over a five-year, period and associations between herd characteristics and herd health are evaluated. Results showed that in 2020 the Dutch goat population consisted of 670,842 goats, distributed over 14,730 unique herds and increased by 2.3 % compared to 2019. Between 2016 and 2020, although probably underestimated, recorded mortality rates showed a decline on both small-scale and professional farms, with a strongest decrease on farms with herd sizes over more than 200 animals. Seventy-five percent of all professional farms registered animal introductions, in addition to 63 % of small-scale farms, including 2439 imported goats. Performing risks analyses requires demographic knowledge of the goat industry. During and after several disease outbreaks, such as bluetongue and Schmallenberg virus disease, the data analysis proved to function as a valuable tool, however, appeared just as important for recording outbreak-free data. Since its start in 2006, the concept of the data-analysis has continuously been improved, and will in the future be further developed, especially if more complete data sets become available. Subsequently, data analysis will increasingly support monitoring and surveillance of goat health and welfare.

Immigration drives ship rat population irruptions in marginal high‐elevation habitat in response to pulsed resources

AbstractPest animal populations, such as rodents, often irrupt in response to pulsed resources. However, few studies have considered how understanding the propagation of irruptions across landscapes could lead to more efficient pest suppression. Resource pulses might create temporary source–sink dynamics in heterogeneous environments, whereby reservoirs of animals living in high‐quality habitat increase and spill over into more marginal habitat. Low‐density populations in marginal habitat could also increase through in situ breeding by residents in response to increased food availability. Understanding the relative importance of these two nonmutually exclusive processes is important as pest outbreaks could potentially be more efficiently controlled by targeting source populations early in an outbreak. We used a Bayesian hierarchical model to estimate the importance of density‐dependent emigration from lower elevation habitats versus in situ breeding by resident animals to the population growth of invasive ship rats (Rattus rattus) in marginal, high elevation habitats during a pulsed resource event (beech seed mast). We found that emigration from lower elevations was important for facilitating rapid population growth at high elevations, enabling rats to reach peak densities of 10.6 rats ha−1. Without immigration, rats were predicted to reach peak densities of only 1.8 rats ha−1 at high elevation, given their densities in that habitat when we started monitoring (0.6 rats ha−1). This result suggests that rat control that targets low and mid‐elevations only may be sufficient to suppress irruptions in high‐elevation habitat if control effectively prevents immigration. Our study suggests spillover from higher quality habitats may enable outbreaks to rapidly propagate over landscapes. However, for r‐selected taxa such as rodents, even very low densities of animals living in marginal habitats can increase significantly when resource pulses occur, albeit at lower densities than for populations in higher quality habitat.

Global trends in antimicrobial use in food-producing animals: 2020 to 2030.

Use of antimicrobials in farming has enabled the growth of intensive animal production and helped in meeting the global increase in demand for animal protein. However, the widespread use of veterinary antimicrobials drives antimicrobial resistance, with important consequences for animal health, and potentially human health. Global monitoring of antimicrobial use is essential: first, to track progress in reducing the reliance of farming on antimicrobials. Second, to identify countries where antimicrobial-stewardship efforts should be targeted to curb antimicrobial resistance. Data on usage of antimicrobials in food animals were collected from 42 countries. Multivariate regression models were used in combination with projections of animal counts for cattle, sheep, chicken, and pigs from the Food and Agriculture Organization to estimate global antimicrobial usage of veterinary antimicrobials in 2020 and 2030. Maps of animal densities were used to identify geographic hotspots of antimicrobial use. In each country, estimates of antimicrobial use (tonnes) were calibrated to match continental-level reports of antimicrobial use intensity (milligrams per kilogram of animal) from the World Organization for Animal Health, as well as country-level reports of antimicrobial use from countries that made this information publicly available. Globally, antimicrobial usage was estimated at 99,502 tonnes (95% CI 68,535-198,052) in 2020 and is projected, based on current trends, to increase by 8.0% to 107,472 tonnes (95% CI: 75,927-202,661) by 2030. Hotspots of antimicrobial use were overwhelmingly in Asia (67%), while <1% were in Africa. Findings indicate higher global antimicrobial usage in 2030 compared to prior projections that used data from 2017; this is likely associated with an upward revision of antimicrobial use in Asia/Oceania (~6,000 tonnes) and the Americas (~4,000 tonnes). National-level reporting of antimicrobial use should be encouraged to better evaluate the impact of national policies on antimicrobial use levels.

Savanna resilience to droughts increases with the proportion of browsing wild herbivores and plant functional diversity

Abstract Maintaining the resilience and functionality of savannas is key to sustaining the ecosystem services they provide. This maintenance is largely dependent on the resilience of savannas to stressors, such as prolonged droughts. The resilience to drought is largely determined by the interaction of herbivores and the functional composition of vegetation. So far, our understanding and ability to predict the response of savannas to drought under different types of rangeland use and as a function of vegetation composition are still limited. In this study, we used the ecohydrological, spatially‐explicit savanna model EcoHyD to determine if the resilience of a savanna rangeland towards prolonged droughts can be enhanced by the choice of rangeland use type (grazer‐dominated, mixed‐feeders or browser‐dominated) and animal density. We evaluated the ability of a Namibian savanna system to withstand droughts and recover from droughts based on its perennial grass cover and the overall species composition. Generally, we determined a low resilience under high grazer densities. Most importantly, we found that functional diversification of herbivores and plants acted as resilience insurance against droughts, leading to greater resistance and recovery of perennial grasses. In particular, a higher proportion of herbivores allowed for higher resilience, probably also due to a short‐term switch to more drought‐resistant or unpalatable species. In this case, herbivore diversification was of high self‐regulatory value by reestablishing trophic complexity, reducing the need for additional management interventions. Synthesis and applications: Savanna systems will be more resistant to drought if (i) a dense perennial grass cover is maintained, protecting the topsoil from heat‐induced water losses and erosion, encompassing functionally important species that are particularly well adapted to water stress and that are palatable, if (ii) the grazing pressure is adjusted to the productivity of the system, and (iii) the herbivore community includes browsers.

Wild animal densities as predictors of cattle disease risks and breed types in southwestern Uganda.

This study investigated the spatial distribution of wild ungulates that pastoralist communities perceive as culprits in the transmission of cattle diseases outside protected areas in southwestern Uganda.Diseases are hypothesized as having influence on pastoralists' choice of cattle breed types. Until now, there have been no studies conducted on spatial patterns of wild animal species association with cattle breeds reared in Lake Mburo Conservation Area (LMCA), and how diseases transmitted therein potentially influence cattle breed herd sizes. Animal population survey was carried out on cattle and wild ungulate species along transect lines laid perpendicular to the northern boundary of Lake Mburo National Park (LMNP). Data on the costs of cattle mortality and disease control were gathered using face-to-face interviews. We used SPSS version 17 for descriptive statistics to summarize unit cost of disease control at herd level, whereas chi-square (χ2) tests of goodness-of-fit were used to analyze observations on frequency of wild animal sightings, whose association with spatial distribution patterns of cattle breeds was examined using Pearson correlation test. Our results show inverse association of distance away from LMNP with wild animal populations and the cost of cattle disease control. The mean population of exotic cattle significantly increased as that of indigenous cattle decreased with increasing distance from LMNP. In a similar way, the cost of disease control and cattle abortion incidences were much lower in rangelands far away from LMNP (R2 = 0.965,p < 0.001). Spatial distribution of wild ungulates was significantly associated with reported cattle mortality, disease, and cost of disease control. Diseases and their costs of control potentially influenced spatial patterns of cattle breeds and breed herd sizes in LMCA, which in turn could affect range resource use for conserving different species of wild animals outside protected area.

Productivity gains, evolution of productive performances, and profitability of organic ruminant farms: farm size and feed self-sufficiency matter

We analyzed the productive and economic performances of a constant sample of 58 organic ruminant farms between 2014 and 2018, in a mountain grassland area (French Massif Central). Over this 5-year period, these farms expanded without increasing their labor productivity or animal density per hectare of forage area. While animal productivity has been maintained, we observed a decrease in feed self-sufficiency, and thus, an increase in feed purchases. Over the period, the volume of inputs used has increased more rapidly than agricultural production, resulting in a decline in the productivity surplus (PS) at a rate of −2.6%/year. As the prices of products and inputs were relatively stable, this decrease in PS was financed at 41% by an increase in public aid (drought aid, agri-environmental climate measures) and at 49% by a decrease in profitability for the farmer (the farm income per farmer fell by 40%). A binary choice estimation model, i.e., which variables determine the positive or negative sign of the PS, showed that farm size was a negative determinant of the PS, as was system specialization, while feed self-sufficiency was a positive determinant. More statistically robust references on price indices of organic farming (OF) products and inputs, as well as long-term follow-ups of OF farms, are needed to validate these original results, which were based on a small sample size and a short period of time.

POPULATION DENSITY OF RESIDENT AND NON-RESIDENT FOREST SMALL MAMMALS

When assessing the abundance of small mammals using traditional methods, an abundance index, the number of individuals per unit of trapping effort, is usually applied. Due to the different relationships of species to various traps and baits, the true ratio of species in nature may not coincide with the estimated one. In most cases, the presence of a non-resident component in the population size remains outside the attention of researchers, while dispersal is a key element for many demographic processes. A method is proposed for calculating the density (individuals per area) of resident and non-resident animals when using mark-recapture live-traps arranged in lines. For three mass species of small forest mammals (red-backed voles, common shrew and masked shrew), the dynamics of the density of the resident and non-resident population were studied over 18 years. In most cases, the red-backed vole dominated the population of small mammals. According to long-term average data, the proportion of non-resident individuals in the population of the three species did not differ, averaging 12.6% of the total density. The dependence of the level of non-resident activity in the red-backed vole on the density of resident animals was shown. In shrews, the density of non-residents did not depend on the density of resident ones. The technique allows for a wide range of ecological problems to be solved and it can be used to monitor the state and structure of communities of small mammals.

Grazing by semi‐feral cattle and horses supports plant species richness and uniqueness in grasslands

AbstractQuestionHow does naturalistic grazing (trophic rewilding with large herbivores), in contrast to mowing and free succession (no grazing), affect plant community composition and species richness in temperate grassland grazed by semi‐feral cattle and horses?LocationMols Laboratory, Denmark.MethodsWe investigated grazing exclosures in the rewilding area of the Mols Laboratory, four years after its establishment. We focused on moist to dry grassland vegetation, that is, excluding scrub and woodland. Each experimental block consisted of five 5 × 9 m plots, representing four fenced treatments, that is, summer‐only grazing, winter‐only grazing, full exclosure with annual autumn mowing and full exclosure with passive succession. The matrix (the fifth treatment) was grazed by large herbivores at close‐to‐natural densities, that is, regulated bottom‐up by the carrying capacity of the area. Hence, even the seasonal grazing treatments were grazed at close‐to‐natural animal density. Quantitative plant community composition was assessed using the point‐intercept method in 25 × 25 cm quadrats, supplemented with biomass calibration models based on additional quadrats, in which above‐ground plant biomass was harvested after recording and the material sorted to species and weighed. Uniqueness was assessed as the sum of inverse range sizes for constituent species (unicity).ResultsWe found an appreciably higher plant species richness in grazing treatments than under both annual mowing and full exclosure, but only minor differences between seasonal grazing treatments. Uniqueness was highest in year‐round and winter‐only grazing and lowest in summer‐only grazing. The forb:graminoid ratio tended to be high in the winter‐only grazing treatment, whereas annual mowing was associated with dominance of graminoids over forbs. Full‐exclosure plots had accumulation of litter and the lowest species richness. Initial heterogeneity between plots within blocks and a systematic difference between blocks in moist and dry grasslands may have diluted treatment effects at this early point after the onset of the experiment. Data analysis using the biomass estimates derived from the calibration models yielded only minor differences in the patterns described above, when compared to the results obtained using the raw number of intercepts.ConclusionsNaturalistic grazing is a goal in itself in ecological restoration, but also proposed as an efficient management tool to promote conservation of grassland plants and communities. We found both plant species richness and the prevalence of regionally rarer species (uni) to be higher with grazing than mowing or abandonment. Similarly, the tendency for forbs to prevail under grazing may translate into enhanced floral resources for anthophilous insects. Summer‐only grazing at low density of large herbivores was not significantly different from winter‐only and year‐round grazing, but this treatment was much closer to natural grazing than intensive summer grazing typical of agri‐environmental practices.

АНАЛІЗ СУЧАСНОГО СТАНУ РЕСУРСІВМИСЛИВСЬКИХ ГОСПОДАРСТВ УКРАЇНИ

Тask statement. The hunting industry is an important part of the state's national economy, as it plays one of the key roles in the use and preservation of natural resources and is a source of financial income for the state and regional budgets. However, at the current stage of the development of the economy of Ukraine, the hunting industry faces many problems of resource provision, which can affect the reduction of the industry's potential. Therefore, the analysis of the available resources for hunting farms in Ukraine is of practical importance, which will make it possible to identify the main problems that slow down the development of the industry, and to outline possible ways to solve them. Research results. The hunting industry of Ukraine has natural, geographical, and climatic conditions for successful development. However, during the studied period, there is a decrease in the area of hunting grounds, mainly in the Steppe due to the occupation of the territory by Russia. Among the forms of management in the hunting industry, public organizations of the Ukrainian Society of Hunters and Fishermen and enterprises of the State Forest Resources Agency predominate, however, the number and specific weight of land use by enterprises of other forms of ownership is increasing. As a result, the total number of hunting farms increases and their average size decreases, which will gradually shape their optimal land use. In general, the personnel structure of hunting farms remained almost unchanged, which indicates the possibility of stable operation of hunting farms. However, the number of workers in hunting farms in the Steppe decreased, especially hunters, and in the Forest Steppe and Polissia, it increased. As a result, the actual number of hunters in the Forest Steppe and Polissia farms exceeds the minimum required, and in the Steppe, there is a shortage of hunters. The analysis of the dynamics of the number of hunting animals shows that the number of fur animals in the hunting farms of Ukraine tends to constantly decrease, and the population of ungulates gradually increased after a decrease in the early 2000s, but in 2011-2015 it decreased. The structure and density of the population of hunting animals differ by natural and climatic zones, which objectively forms differences in the organization and effectiveness of hunting farms/ The load of hunting animals per hunter differs in natural and climatic zones and has quantitative and structural differences, as well as differences in dynamics. The higher load per hunter in the Steppe is due to the relatively higher density of fur animals and feathered game and the lower availability of hunter vacancies The minimum number of hunters should be determined taking into account the density of hunting animals, and not only by the area of land use. An effective way to increase the number of hunting species of animals is the creation of aviary farms, which in a limited area have significant advantages over free breeding, however, such resource capabilities of hunting farms have been significantly reduced due to the occupation of territories. Conclusion. The negative trends in the development of the resources of hunting farms actualize the search for ways to increase the efficiency of their functioning, in particular, based on a comprehensive analysis of indicators of the activity of hunting farms in Ukraine.

Ocorrência de laminite clínica após adaptação ao confinamento: efeitos na morfologia, densidade e composição mineral do casco de bovinos Nelore após terminação

ABSTRACT: Laminitis is a disease that affects the dermis and epidermis of the bovine hoof, generating changes in the hoof capsule. This study evaluated the effects of clinical laminitis diagnosed after the adaptation phase to confinement on the morphology, density, and mineral composition of the hoof of Nellore cattle after finishing. The animals were separated in the first weeks of confinement into a sick group (SG), with clinical laminitis, and a healthy group (HG). SG animals had higher heel length, dorsal wall length, toe height, and diagonal hoof length (p&lt;0.05) than healthy animals. The dermal laminae had similar measurements for thickness, length, and spacing between them between SG and HG. Animals with laminitis showed congestion, hemorrhage, and basement membrane irregularities on histology. Computed microtomography (μCT) revealed that the hoof density of sick animals is lower than healthy ones. According to the mineral composition by energy-dispersive X-ray fluorescence (ED-XRF) spectrometry, the hooves of animals with laminitis (SG) and healthy ones (HG) were not biochemically different. Therefore, the occurrence of clinical laminitis in Nellore cattle in the first weeks of confinement causes an increase in the morphometric parameters of the hoof capsule and a reduction in the density of the abaxial hoof wall evaluated after the finishing period. This disease does not promote changes in the histomorphometric parameters of the dermal laminae and the percentage of minerals in the abaxial hoof wall.

Habitat type affects the structure but not the composition of dung beetle (Coleoptera: Scarabaeinae) assemblages in a tropical deciduous forest of southeastern Mexico

Abstract In this study, we compared the Scarabaeinae (Coleoptera) assemblages between two contrasting habitats (conserved forest versus urban habitat), located between the boundary of an urban zone and a protected area within the Mexican state of Chiapas. We collected 1003 individuals of 22 species and 12 genera. The composition of assemblages was similar between habitats, with a high species dominance. However, the identity of the dominant species differed between habitats, with 11 species considered indicators of one of the two conditions (five species in the conserved forest sites and six species in urban habitat sites), whereas three other species exhibited generalist habits. Large paracoprids predominate in the conserved forest, and small paracoprids in the urban habitat. The apparent homogeneity in the dung beetle assemblages probably is due to the high density of domestic and feral animals replacing native mammals and is promoted by the loss of forest-dependent species caused by continuous landscape fragmentation. Nonetheless, the association of some species with forest habitat and the differences in the structure of functional groups indicate the importance of conserving these forest remnants, which would help to mitigate the negative impact of urbanised areas, as these species are generally sensitive to the habitat fragmentation process.

How Many Reindeer? UAV Surveys as an Alternative to Helicopter or Ground Surveys for Estimating Population Abundance in Open Landscapes

Conservation of wildlife depends on precise and unbiased knowledge on the abundance and distribution of species. It is challenging to choose appropriate methods to obtain a sufficiently high detectability and spatial coverage matching the species characteristics and spatiotemporal use of the landscape. In remote regions, such as in the Arctic, monitoring efforts are often resource-intensive and there is a need for cheap and precise alternative methods. Here, we compare an uncrewed aerial vehicle (UAV; quadcopter) pilot survey of the non-gregarious Svalbard reindeer to traditional population abundance surveys from ground and helicopter to investigate whether UAVs can be an efficient alternative technology. We found that the UAV survey underestimated reindeer abundance compared to the traditional abundance surveys when used at management relevant spatial scales. Observer variation in reindeer detection on UAV imagery was influenced by the RGB greenness index and mean blue channel. In future studies, we suggest testing long-range fixed-wing UAVs to increase the sample size of reindeer and area coverage and incorporate detection probability in animal density models from UAV imagery. In addition, we encourage focus on more efficient post-processing techniques, including automatic animal object identification with machine learning and analytical methods that account for uncertainties.

Identification of familial networks reveals sex-specific density dependence in the dispersal and reproductive success of an endangered ungulate

Density is an important demographic parameter that is commonly overlooked in studies of wild populations. Here, we examined the effects of variable spatially explicit density on a range of demographic parameters in a wild population of a cryptic ungulate, boreal woodland caribou (Rangifer tarandus caribou). Using non-invasive genetic sampling, we applied spatial capture–recapture methods with landscape covariates to estimate the density of boreal woodland caribou across a 108,806 km2 study area. We then created a familial network from the reconstructed parent–offspring relationships to determine whether spatial density influenced sex-specific individual reproductive success, female pregnancy status, and dispersal distance. We found that animal density varied greatly in response to land cover types and disturbance; animal density was most influenced by landscape composition and distance to roads varying from 0 in areas with &amp;gt;20% deciduous cover to 270 caribou per 1,000 km2 in areas presenting contiguous older coniferous cover. We found that both male and female reproductive success varied with density, with males showing a higher probability of having offspring in higher-density areas, and the opposite for females. No differences were found in female pregnancy rates occurring in high- and low-density areas. Dispersal distances varied with density, with offspring moving shorter distances when parents were found in higher-density areas. Familial networks showed lower-closeness centrality and lower-degree centrality for females in higher-density areas, indicating that females found in higher-density areas tend to be less broadly associated with animals across the range. Although high-density areas do reflect good-quality caribou habitat, the observed decreased closeness and degree centrality measures, dispersal rates, and lower female recruitment rates suggest that remnant habitat patches across the landscape may create population sinks.

“BACACIX”, a spatial index combining proxies of bovine and badger space use associated with extended Mycobacterium bovis circulation in France

To better prevent and control multi-host pathogen circulation over large areas, it is essential to identify patterns of disease persistence within host communities involved in pathogen circulation at a macroscale. The aim of this study was to design and calculate “BACACIX”, a spatial index of indirect contacts between cattle and badgers, two species involved in the circulation of Mycobacterium bovis, one of the main causative agents of bovine tuberculosis (bTB), in some areas of France. The index combined spatial models of land use distribution (the probable distribution defining animal use of space) based on pasture location for cattle, and based on land cover for badgers, with proxies for animal density for both species. For badgers, we used two series of census data of badger setts in two regions of France to evaluate our model of badger space use distribution (also known as utilization distribution), and analyzed the relationship between BACACIX and the upsurge of bovine tuberculosis observed in several regions of France during the decade after the country obtained the officially bTB-free status in 2001. We observed high values of BACACIX from the southwest to the northeast of France and from Brittany to the Channel coast. Conversely, in two areas (north-central area and Mediterranean coast), index values were low, suggesting that indirect cattle–badger contacts were unlikely. In the two series of census data of badger setts that we analyzed, 96.5% and 87% of the global positioning system (GPS) locations of badger setts, respectively were located in the calculated badger space use distribution. A logistic regression model showed that after controlling bTB over the previous decade, the value of the index was positively associated with the risk of cattle outbreaks between 2001 and 2010 (OR = 1.57). In addition, the risk of bTB occurrence in cattle decreased when the pasture area outside the badger space use distribution increased. In the future, the spatial index of indirect cattle–badger contacts we propose could help to better target bTB surveillance and control in France.

Community Characteristics and Niche Analysis of Soil Animals in Returning Farmland to Forest Areas on the Loess Plateau

Niche theory is significant for understanding the function of community structure, interspecific relationships, and community dynamic succession. However, there are few studies on the soil animal niche in returning farmland to forest areas on the Loess Plateau, making it challenging to comprehend the utilization of soil animal resources, the stability of the local community, and the succession process in the areas. Therefore, this study collected soil animals in five typical vegetation types: Robinia pseudoacacia (R), Hippophae rhamnoides (H), Populus simonii (P), Pinus tabulaeformis (T), and Armeniaca sibirica x Hippophae rhamnoides (M), with abandoned grassland (G) used as a control group. Then, the number of soil animal taxa, individuals, diversity, and niche were sampled and examined in the study areas during the four seasons of spring, summer, autumn, and winter using the manual sorting method and the Tullgren method. The results revealed that 3872 soil animals from 3 Phyla, 8 Classes, 22 Orders, and 49 Families were captured in the study areas. The dominant groups of soil macrofauna were Diptera larvae, Julidae, and Formicidae, and the dominant groups of meso–micro soil fauna were Oribatida, Protospira, and Collembola juveniles. Soil animals have rich nutritional function groups, with the most saprophytic soil animal groups. The individual density and taxa number of soil animals in G were lower than other vegetation on the whole. H, M, and P had a higher Shannon–Winner index than the other vegetation. Seasonal changes had different effects on macro and meso–micro soil fauna. The diversity of soil macrofauna is higher in spring and summer, and that of meso–micro soil fauna is higher in autumn and winter. Oribatida, Diptera Larvae, and Formicidae had a large niche width in the main taxa of soil animals, with universal adaptability to the environment. Cicadellidae and Culicidae had narrow niche widths and were highly dependent on resources and the environment. There were 67 pairs of highly overlapped (Oik &gt; 0.8) taxa of soil animals and 56 pairs of moderately overlapped (0.6 &lt; Oik ≤ 0.8) taxa, accounting for 80.39% of the total number of taxa. Soil animals had high commonality in resource utilization, intense competition, and poor community stability. As a result, we can conclude that the soil animal community in the study areas was in the stage of succession.