Setts Research Articles

Use of European badger setts by invasive raccoons and other mesocarnivores in western Poland

AbstractWe describe a cases of main setts of European badger Meles meles being used by non-native raccoons Procyon lotor and raccoon dogs Nyctereutes procyonoides and native red foxes Vulpes vulpes in western Poland. From April to June 2022 and from November 2022 to mid-April 2023, we monitored the main badger setts (27 in spring and 14 in winter) using camera traps. We recorded the presence of red foxes in 63.0%, raccoon dogs in 48.1% and raccoons in 22.2% of the setts. These species were more likely to occupy badger setts in winter. The raccoon is the second invasive species after the raccoon dog to use badger setts for shelter in Poland. In four setts, we observed that two native (badger and red fox) and two non-native (raccoon and raccoon dog) mesocarnivores cohabited the same sett.

Trapping Sets Search Using the Method of Mixed Integer Linear Programming with a Priori List of Variable Nodes

Purpose of research is to develop a new high-speed method for searching trappin sets in graph codes, ensuring the completeness of the search.Methods. There are two approaches to finding trappin sets. The first, based on the Monte Carlo method with a biased probability estimation using Importance Sampling, involves the use of a decoder. The advantage of this approach is its high performance. The disadvantages are the dependence on decoder parameters and channel characteristics and the finite probability of missing trappin sets. The second approach is based on the use of linear programming methods. The advantage of this approach is the completeness of the resulting list of trappin sets, due to its independence from the decoder parameters and channel characteristics. The disadvantage of this approach is its high computational complexity. In the article, within the framework of the second approach, a new method for searching trappin sets with less computational complexity is proposed. The method involves solving a mixed integer linear programming problem using an a priori list of code vertices participating in the shortest cycles in the code graph. Results. Using the proposed method, a search for trappin sets was performed for several low-density codes. For this purpose, the mathematical linear programming package IBM CPLEX version 12.8 was used, which was run on 32 threads of a 16-core AMD Ryzen 3950X processor with 32GB of RAM (DDR4). In the Margulis code (2640, 1320), using the proposed method, the trappin set TS(6,6) was found in a time of 0.53 s. The speedup provided by the method proposed in the paper compared to the Velazquez-Subramani method is 8252.415 times. Thanks to the high speed and completeness of the search, trappin sets were found for the first time TS(62,16) and TS(52,14) in the Margulis code (4896, 2474 ).Conclusion. The paper proposes a new method for searching trapping sets by solving a mixed integer linear programming problem with an a priori list of code. The method is fast and provides completeness of the search.

Badgers remain fearless in the face of simulated wolf presence near their setts.

Many mesocarnivores are fossorial and use burrow systems to avoid predators. But fossorial animals cannot stay safely underground forever; they must also risk emerging overground to forage and find mates. To make this trade-off effectively and maximise their own fitness, it is imperative they assess how risk varies in space and time and adapt their denning behaviour accordingly. We used the badger in Białowieża Forest, Poland, as a model for investigating how the denning behaviour of a fossorial mesocarnivore varies in response to short-term large carnivore risk. To this end, we experimentally simulated perceived wolf presence outside 10 badger setts using audio playbacks of wolves (their howls). We assayed two behavioural measures of fear: badger emergence time from setts on the day playbacks were broadcast and their presence in setts on the day after. We found that neither badger emergence time nor next-day sett use varied in response to wolf playbacks. The results of the present study contrast with a previous study of ours that found badgers used setts in areas with high landscape level perceived wolf risk less often than those in lower-risk areas. Together, these papers' findings suggest that different spatiotemporal scales of perceived risk can have differential effects on badger behaviour. We conclude that rather than take risk avoidance measures at all risky times and places, badgers likely display a diversity of reactions to large carnivore presence that depend on the context and spatiotemporal scale of the risk being perceived.

Combined electrical resistivity tomography and ground penetrating radar to map Eurasian badger (Meles Meles) burrows in clay-rich flood embankments (levees)

Globally, earth embankments are used to protect against flooding. Raised above the surrounding water table, these embankments make ideal habitats for many burrowing animals whose burrows can impact their structural integrity. Ground Penetrating Radar (GPR) is commonly used to identify and map animal burrows and other small cavities. However, the depth of investigation of a GPR survey can be severely limited in saline and clay-rich environments, soil properties commonly associated with flood embankments. In contrast, Electrical Resistivity Tomography (ERT) can image subsurface voids in conductive ground conditions but has been rarely used to image animal burrows. Here we aim to assess the efficacy of ERT and GPR to image two badger burrow networks, called ‘setts’, located in clay embankments on the River Ouse, Yorkshire, UK. The two setts were excavated to validate the geophysical results, and the soil was characterised through logging and geotechnical analysis to develop a ground model of the site. We find that ERT can accurately resolve tunnels down to 1.5 m depth, map the structure of a multi-entrance badger sett and successfully identify the end of the tunnels. This result compares favourably to the GPR surveys, which mapped all but the deepest tunnels, limited by its penetration depth due to clay soils. Our results show that ERT can be used as a primary survey tool for animal burrows in clay-rich environments and can be validated using co-located GPR surveys if penetration depth is sufficient. The implications of this study may allow embankment managers to map burrow networks, assess flood embankment stability, minimise repair costs, and reduce unexpected failures during flood events. Additionally, a better understanding of how, for example, local heterogeneities impact badgers' burrow geometry may be achievable using these geophysical methods, as they provide a non-destructive, repeatable method for imaging setts.

“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.

Engaging With Farmers to Explore Correlates of Bovine Tuberculosis Risk in an Internationally Important Heritage Landscape: The Burren, in the West of Ireland.

Bovith recene tuberculosis (bTB) continues to be a pathogen of concern in several countries globally. Analysis of areas that have higher incidences of bTB outbreaks has demonstrated how risk is not equally distributed, and local data collection, analysis and participatory engagement is required to develop tailored approaches. The Burren, an internationally important heritage landscape, has been an area of higher bTB incidence for many years in Ireland, and owing to its unique geology and farming heritage a survey was developed to engage with local farmers to gain greater insight into farming practices and bTB control to inform tailored approaches. The survey gathered data on the farm and animal management approaches being used within the Burren, including local farming techniques like the use of “winterage” (grazing exposed limestone dominated uplands). Thematic analysis of free text responses was undertaken. Quantitative data were then explored using statistical models to assess associations with recent (<3 years) self-reported bTB breakdown risk. There was a high number of responses demonstrating a high degree of willingness to engage on the issue. Thematic analysis suggested that wildlife and its management (culling and vaccination), testing quality, and its impact on the bTB scheme, and pessimism around eradication were important themes. Statistical analysis suggested that increasing bTB risk was primarily related to increasing herd-size and the percentage of herd owner's land inaccessible to those attempting to locate badger setts. There was less evidence for associations relating to the amount of time, or which season (i.e., summer), farmers utilized “winterage”. The results of the study will feed back directly to local bTB management plans and further stakeholder engagement and is an exemplar for local tailoring of national control measures in situations of high incidences of bTB outbreaks in particular areas.

Northern Ireland farm-level management factors for recurrent bovine tuberculosis herd breakdowns.

Bovine tuberculosis (bTB) is a chronic, infectious and zoonotic disease of domestic and wild animals caused mainly by Mycobacterium bovis. This study investigated farm management factors associated with recurrent bTB herd breakdowns (n = 2935) disclosed in the period 23 May 2016 to 21 May 2018 and is a follow-up to our 2020 paper which looked at long duration bTB herd breakdowns. A case control study design was used to construct an explanatory set of farm-level management factors associated with recurrent bTB herd breakdowns. In Northern Ireland, a Department of Agriculture Environment and Rural Affairs (DAERA) Veterinarian investigates bTB herd breakdowns using standardised guidelines to allocate a disease source. In this study, source was strongly linked to carryover of infection, suggesting that the diagnostic tests had failed to clear herd infection during the breakdown period. Other results from this study associated with recurrent bTB herd breakdowns were herd size and type (dairy herds 43% of cases), with both these variables intrinsically linked. Other associated risk factors were time of application of slurry, badger access to silage clamps, badger setts in the locality, cattle grazing silage fields immediately post-harvest, number of parcels of land the farmer associated with bTB, number of land parcels used for grazing and region of the country.

Ecological factors influencing the selection of sett location by the Asian badger Meles leucurus

We studied the sett characteristics and habitat variables of the Asian badger Meles leucurus in a temperate forest in South Korea. Logistic regression models were utilized to explain the effects of habitat variables on the location of badger setts. The presence of rocks and trees nearby and of dense ground vegetation and sub-overstory vegetation were correlated positively with sett location. Abundance of setts was higher in deciduous forest compared with coniferous forest, mixed forest and non-forest. The animals showed a preference for a steeper slope of sett location, which likely allows for easier removal of soil during sett settling, as well as improved drainage in that area. In low and high altitudinal areas disturbed by humans, a lower abundance of setts was found. Thus, selection of sett location was strongly influenced by structures around the setts, vegetation cover, forest type, slope and altitude. These variables should be considered and handled carefully though forest management for the conservation of the mammals and their habitats.

Current status and management of sugarcanesmut disease in North India

Sugarcane an important cash crop suffers from several fungal, bacterial, phytoplasmal and viral diseases. Of the fungal diseases, smut had been a major constraint to sugarcane production in most of the sugarcane growing tracts of the country. The disease is caused by fungus Sporisoriumscitamineum (Syn: Ustilago scitaminea).Primary transmission of the disease takes place trough infected setts. Earlier this disease was kept under control through heat therapy (Aerated steam therapy /moist hot air treatment) of seed canes by the sugar mills and sugarcane research centers. However, since last couple of years, sett treatment practice has been stopped and smut incidence increased by many folds. To know the current scenario of sugarcane diseases in the subtropical region, authors surveyed the reserved areas of 44 sugar mills in Haryana, Punjab, Uttar Pradesh, Bihar and Uttrakhand states during 2010-2019 crop seasons regularly. In Haryana, smut prevails as major disease in most of the sugar mills and its incidence is increasing rapidly. The disease incidence ranged from 1.0 to 40.0% in ratoons and traces to 9.0% in plant crops of varieties viz. Co 0238, Co 89003, CoH 116, CoH 119, CoH 150, CoH 152, CoH 156, CoH 160, CoJ 85, CoJ 88 and CoS 8436. In Shahabad area most of the fields of variety CoH 160 had severe smut incidence i.e. up to 40.0% in ratoon and 9.0% on plant crops. Similarly in the varieties Co 0238, Co 89003 and CoJ 88 cultivated under Punjab, traces to 11.0% incidence in ratoon and up to 5.0% in plant crops was found. Further, in western UP occurrence of smut was moderate to 6.5% in ratoon and traces to 1.5% in plant crops of cultivated varieties. The maximum disease incidence (T-2.5%) was noted in Harinagar (Bihar) on variety CoSe98231, whereas, under Laksar (Uttrakhand) it observed to a tune of 4.5% and 6.0% on varieties CoSe 03234 and CoSe 01434, respectively. In the light of observations recoded over the period, advisories were issued regularly to the sugar mills for its prevention and farmers of the state have adopted smut management practices i.e. roguing of smut whips followed by spray of Propiconazole 25EC @ 0.1%. Farmers and sugar mill officials of the state have been advised to adopt seed cane treatment practices with Sett Treatment Device, recently developed by ICAR-SBI, Coimbatore to combat this disease. The Haryana sugar Federation is also advised to promote sett treatment practice in the state. Since last four years all the Co-operative sugar mills have been running tractor driven sett treatment units for seed cane treatment at farmer fields to manage sett borne diseases. Since smut has emerged as a serious disease, sugar industry should take up the disease management in a systematic way to sustain sugarcane cultivation in the region and also to prevent buildup of disease epidemics.

Underground diversity: Uropodina mites (Acari: Mesostigmata) from European badger (Meles meles) nests

Badgers can gather huge quantities of organic material to build their nests for winter time and to rear their cubs. Moreover, badger burrows (setts) are characterized by specific microclimate with quite stable temperature and humidity. Their fauna is poorly studied, especially in respect of saprobiontic Uropodina mites. In 2018–2019, we monitored 94 badger setts to search for nest material that had been thrown away during cleaning of the chambers after mating and winter sleep. In the collected material from 32 badger nests, we found 413 Uropodina mites of 16 species, in various stages of development (adults, protonymphs, and deutonymphs). The community was dominated by three mite species: Trematura patavina (22.5%, n = 93), Oodinychus ovalis (17.2%, n = 71), and Olodiscus minima (15.5%, n = 64). Other nidicolous—i.e., nest-dwelling—species included: Nenteria oudemansi (14.8%, n = 61), Phaulodiaspis borealis (7.0%, n = 29), Phaulodiaspis rackei (4.6%, n = 19), Uroseius hunzikeri (1.7%, n = 7), Uropoda orbicularis (1.5%, n = 6), and Apionoseius infirmus (1.0%, n = 4). The most frequent species were: Oodinychus ovalis (62.5%, 20 nests), N. oudemansi (46.9%, 15 nests), and Olodiscus minima (40.6%, 13 nests). Detrended correspondence analysis indicated that the Uropodina community from badger nests differed from that of mole nests, studied earlier. In setts, the Uropodina community included T. patavina and N. oudemansi, which were for the first time recorded from underground badger nests. This is the first record of N. oudemansi from Poland.

Fossoriality in a risky landscape: badger sett use varies with perceived wolf risk

AbstractMany medium‐sized carnivores are fossorial and use burrow systems to reduce predation risk or avoid predators. But fossorial species cannot stay safely underground forever, and they must also risk emerging overground, to forage and find mates. To make this trade‐off effectively and maximize their own fitness, it is imperative they assess how predation risk varies in space and time, and adapt their denning behaviour accordingly. We used European badger (Meles meles) burrows (setts) in Białowieża Forest, Poland as a model for investigating how the denning behaviour of a fossorial mesocarnivore varies across gradients of landscape scale perceived risk imposed by wolves (Canis lupus) and humans, defined as wolf space use and distance to settlements, respectively. We monitored seventeen setts with varying levels of perceived human and wolf risk with camera traps for two months to study three denning behaviours: frequency of badger sett use, frequency of badger sett sharing with other mesocarnivore species and badger emergence time. Frequency of sett use varied relative to perceived wolf but not human risk. Setts in the highest risk areas were used ca. 60% less often than those in the lowest perceived risk areas, and setts with juveniles were only present in areas of lower perceived risk. Food availability, quantified as earthworm abundance in an area of 2.1 km2 around setts, did not affect the frequency setts were used. Emergence time and frequency of sett sharing with other mesocarnivores, which have been proposed to be anti‐predator strategies, did not vary with either perceived risk factor. These results show fossorial species can adapt their use of burrows to the prevailing risk landscape and suggest burrows deserve more attention in studies on the ecological impacts of apex predators.

Grazing cattle exposure to neighbouring herds and badgers in relation to bovine tuberculosis risk

Bovine tuberculosis (bTB) can be spread between and among cattle and wildlife hosts e.g. European badger (Meles meles). The majority of cattle in the UK and Ireland are grazed during the summer, potentially exposing them to Mycobacterium bovis. 18 farms were surveyed (39% dairy, 61% beef; fields n = 697) for one grazing season (May-November 2016, n = 148,461 field days) to quantify the co-occurrence of cattle with badger setts and latrines and adjacency to neighbouring cattle herds. 3% (n = 24) of the fields had a badger sett or latrine recorded, dairy cattle were significantly more likely to co-occur with badger setts and latrines than beef cattle. Most farms (89%) grazed cattle adjacent to a neighbouring herd, which accounted for 18% of the grazing season. Potential exposure to neighbouring herds did not differ between production systems but did vary between life stages. A significant positive association between the proportion of time cattle spent grazing fields with setts present and the historic 1-, 3- and 5- year bTB status (p = 0.007, p = 0.013 and p = 0.013 respectively) was found. However, when cattle were grazed in fields with latrines, a significant negative association was found between the proportion of time cattle spent grazing fields with latrines present and the historic 3- and 5- year bTB status (p = 0.033 and p = 0.012 respectively). Historic bTB status and percentage of days spent beside a neighbouring herd was unrelated. Idiosyncrasies at farm-level and between risk factors indicated that individual farm assessments would be beneficial to understand potential exposure risk.

Interspecific visitation of cattle and badgers to fomites: A transmission risk for bovine tuberculosis?

In Great Britain and Ireland, badgers (Meles meles) are a wildlife reservoir of Mycobacterium bovis and implicated in bovine tuberculosis transmission to domestic cattle. The route of disease transmission is unknown with direct, so‐called “nose‐to‐nose,” contact between hosts being extremely rare. Camera traps were deployed for 64,464 hr on 34 farms to quantify cattle and badger visitation rates in space and time at six farm locations. Badger presence never coincided with cattle presence at the same time, with badger and cattle detection at the same location but at different times being negatively correlated. Badgers were never recorded within farmyards during the present study. Badgers utilized cattle water troughs in fields, but detections were infrequent (equivalent to one badger observed drinking every 87 days). Cattle presence at badger‐associated locations, for example, setts and latrines, were three times more frequent than badger presence at cattle‐associated locations, for example, water troughs. Preventing cattle access to badger setts and latrines and restricting badger access to cattle water troughs may potentially reduce interspecific bTB transmission through reduced indirect contact.

Predicting badger visits to farm yards and making predictions available to farmers.

The use of agricultural resources or environments by wildlife may result in opportunities for transmission of infections amongst wild animals, livestock and humans. Targeted use of biosecurity measures may therefore reduce disease risks, although this requires practical knowledge of where such measures would be most effective, and effective means of communicating risks so that stakeholders can make informed decisions about such investment. In parts of Europe, the European badger Meles meles may act as a wildlife reservoir for Mycobacterium bovis, the causative agent of bovine tuberculosis, and badger visits to farmyards may provide potential opportunities for transmission of M. bovis to cattle. Biosecurity measures are effective in reducing badger activity in farmyards, although it is unclear which farms should be targeted with such measures. We used cameras to monitor badger activity in 155 farmyards in south west England and Wales, and related variations in the presence and frequency of badger visits to farm characteristics. Badgers were recorded on camera in 40% of farmyards monitored. However, the frequency of visits was highly variable, with badgers recorded on >50% of nights in only 10% of farms. The presence of badgers in farmyards was positively associated with the density of badger setts, the number of feed stores and the number of cattle sheds, and negatively associated with the distance to the nearest active badger sett, the presence of a house/dwelling and the number of cattle housed on the farm. The frequency of visits was negatively associated with the distance to the nearest active badger sett and the number of cattle housed. Models predicted the presence/absence of badgers in farmyards with 73% accuracy (62% sensitivity, 81% specificity, using a cut off value of 0.265). Models could not distinguish between farms with low/high frequency of visits, although farms predicted as having badgers present typically had a higher frequency of visits than those that were not. We developed and present an interactive web based application: the Badger Farm Assessment Tool (BFAT), to allow users to enter the characteristics of a farm and generate a relative risk score describing the likelihood of badger visits.

Small carnivores’ cave-dwelling: neo-taphonomic study of a badger (Meles meles) sett and its archaeological implications

ABSTRACT The interaction between hominins and carnivores can lead to archaeological scenarios where these relationships materialise in palimpsests. The alternate use of caves and shelters results in overlapped occupations where the action of both predators becomes difficult to trace. Their presence in archaeological sites like cave/shelter-environments have been sufficiently contrasted, but despite this, few neo-taphonomic studies of small carnivore burrows have been developed, and mostly in open-air sites. Here we present data from a cave identified as a badger sett through photo/video-trap systems. The material recovered was located in 3D, and subsequently analysed from a taphonomic perspective. The scavenging behaviour of this small carnivore shows a wide range of animals with a bias for appendicular elements. Taphonomically, pits/punctures and scores are the most abundant alteration, although some other mechanical damage has been identified, such as crenulated edges and crushing. Small-sized bones present the highest percentage of tooth-marks and, as to skeletal regions, appendicular elements and girdles are the most affected items.

Reduced occupancy of hedgehogs (Erinaceus europaeus) in rural England and Wales: The influence of habitat and an asymmetric intra-guild predator

Agricultural landscapes have become increasingly intensively managed resulting in population declines across a broad range of taxa, including insectivores such as the hedgehog (Erinaceus europaeus). Hedgehog declines have also been attributed to an increase in the abundance of badgers (Meles meles), an intra-guild predator. The status of hedgehogs across the rural landscape at large spatial scales is, however, unknown. In this study, we used footprint tracking tunnels to conduct the first national survey of rural hedgehog populations in England and Wales. Single and two-species occupancy modelling was used to quantify hedgehog occupancy in relation to habitat and predator covariates. Hedgehog occupancy was low (22% nationally), and significantly negatively related to badger sett density and positively related to the built environment. Hedgehogs were also absent from 71% of sites that had no badger setts, indicating that large areas of the rural landscape are not occupied by hedgehogs. Our results provide the first field based national survey of hedgehogs, providing a robust baseline for future monitoring. Furthermore, the combined effects of increasing badger abundance and intensive agriculture may have provided a perfect storm for hedgehogs in rural Britain, leading to worryingly low levels of occupancy over large spatial scales.

Drivers of sett site location by European badgers in Portugal

European badgers (Meles meles) are considered central-place foragers, whose spatial ecology is predominantly determined by sett location. Many studies have assessed the factors determining sett site selection throughout this species’ range, but these have often been geographically limited and have primarily identified locally dependent factors. To infer key factors determining sett location, a broader scale approach is needed. Between June 2014 and January 2017, we surveyed mainland Portugal to detect badger setts in 10 × 10 km cells, corresponding to a total of 657.5 km walked line transects. We detected 54 main setts in 136 surveyed cells. Each sett and non-sett site (i.e. transects without setts) was characterised using bioenvironmental variables (e.g. land cover, presence of human infrastructure, soil). We used generalized linear mixed models to test five hypotheses potentially explaining sett location: land cover composition; anthropogenic disturbance; abiotic environmental drivers; trophic resource availability; and a combined effect of all these factors. Our findings show that the key factors for badger sett site selection in Portugal are: (1) disturbance avoidance (low beehive density; absence of livestock; far from hunting reserves), but with a tendency to be located close to highways and unpaved roads; and (2) ease of excavation (avoidance of sedimentary/metamorphic composite rocks). Although specific factors among these drivers may be more important locally or regionally, these major drivers have also been identified elsewhere in Europe. Our nationwide approach contributes to a broader understanding of general patterns of sett site selection by badgers in southern Europe. Furthermore, it provides the national authorities with novel and broad-scale data to facilitate sustainable species conservation of badgers in the southwestern limit of their range.

Badger setts provide thermal refugia, buffering changeable surface weather conditions

Den use can be crucial in buffering environmental conditions and especially to provide an insulated environment for raising altricial young. Through Sept-Dec 2016 we monitored temperature and humidity at 11 badger setts (burrow systems), using thermal probes inserted over 4–13 sett entrances to a depth of ca. 2 m, supplemented by continuous daily logging at one entrance per sett. Setts were cooler than exterior conditions Sept-Oct, and warmer than exterior conditions Nov-Dec. Setts cooled down when badgers left them to forage by night, and warmed up when badgers occupied them by day. Soil type and aspect also influenced sett temperature. Sett temperature did not affect the weight or body-condition of either adults or maturing cubs in autumn. However, cubs born into setts that were relatively warmer through the preceding autumn-winter were heavier in the following spring than contemporaries born in cooler setts (badgers exhibit delayed implantation), and so warmer setts might benefit early cub growth. We posit that sett quality may be important in providing badgers with a stable thermal refuge from variable weather conditions. More broadly, den use may buffer climate change effects for many fossorial carnivore species.

European badger habitat requirements in the Netherlands – combining ecological niche models with neighbourhood analysis

European badger populations in the Netherlands suffered strong declines in the 1900s, becoming endangered in the 1980s. Despite mitigation actions, recovery of the population has been slow. Here, we use ecological niche modelling, relating 1515 badger sett (burrow) localities to data on topographic, groundwater table, soil type and land‐cover variables, to investigate the factors defining badger habitat suitability. Niche modelling of mobile animals such as badgers is challenging, as relevant features that determine habitat suitability surrounding animal sightings or burrow locations are often unaccounted for. In this study, habitat properties of the entire home range of individuals were incorporated via neighbourhood analysis on land‐cover variables. The neighbourhood analysis was applied at different spatial scales, to assess maximum model fit at the scale most representative of badger home‐range area in the Netherlands, which was approximately 3.6 km2. Our results showed that marine and river clay render highly unsuitable habitat for badgers. Grassland and maize crops presence, typically reported as driving factors, had little effect on badger distribution in the Netherlands. Instead, moderate vegetation cover, remoteness from urban infrastructures and low groundwater tables resulted in optimal conditions. We conclude that food availability is not a limiting factor for badgers in the Netherlands, but rather appropriate soil conditions for sett digging and non‐urban landscapes with sufficient cover for hideout determine their distribution. Our predictions indicate suitable areas that are not currently colonized. The results presented have important implications for management and conservation strategies in the Netherlands. Furthermore, we provide a useful general approach for niche modelling of mobile animals.

Effect of competition and landscape characteristics on mesocarnivore cohabitation in badger setts

AbstractMesocarnivores are becoming increasingly influential in ecosystems due to the ongoing loss of large carnivores. However, interactions within mesocarnivore communities remain poorly understood. We studied how competitive coexistence influences cohabitation of badgers (Meles meles) with other European mesocarnivores, and badger habitat selection at sett site and sett environ scales (within a 700 m radius buffer). We used data on the location and use of 234 badger setts in a 39 000 km2 area of mainland Estonia (Northern Europe) to assess the importance of sett occupancy by badgers, the regional abundance of other mesocarnivores (fox/raccoon dog), bedrock complex and landscape in explaining the presence of other mesocarnivores at badger setts. We also compared data from observed setts and random locations to study sett site selection. Setts where foxes or raccoon dogs were present had a lower proportion of active badger entrances and were more likely to be found in forests of agricultural areas, compared with setts where these species were absent. Sett locations tended to occur more frequently in older meso‐ and eutrophic forests on sandy soils. Badgers tended to avoid human infrastructure at sett locations and in the sett environ when selecting sett locations. Our results reveal the influence of habitat fragmentation and competitive relationships on cohabitation between terrestrial carnivores.