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Effective conservation of group-living forest wildlife requires information on how forest age moderates population parameters. Relationships between forest age and demographics can guide long-term management for wildlife populations that are expanding in relatively young second-growth forests in response to ongoing habitat management. We examined how forest age moderates effects of group density on long-term trends in group size and fledgling production in the endangered red-cockaded woodpecker Dryobates borealis (RCW) on the Savannah River Site, SC (SRS). We used 32 years of RCW monitoring data and generalized additive models to: 1) model long-term changes in average RCW group size and fledgling production; and 2) model effects of neighboring group density and neighboring group sizes across a gradient of forest age within 800 m of a group's cavity tree cluster. Average fledgling production oscillated over 2–3 year periods, but longer term evaluation indicated oscillations dampened and average fledgling production slightly decreased over time. Average group size fluctuated abruptly over 2–3 year periods from 1985 to 1994, but longer term evaluation indicated a general increase in group sizes from 1985 to 1994, followed by declines from 1995 to 2007, and a steady increase after 2010. Average fledgling production increased in response to neighboring group density but decreased as neighboring group sizes increased. In contrast, average group sizes increased in response to greater neighboring group density and neighboring group sizes. Stand age did not affect these relationships. Collectively, these results suggest forest age does not directly moderate effects of neighboring group density or group sizes on long-term average group size and fledgling production in the SRS RCW population. Although forest structure has been linked to increased RCW group sizes and productivity, our results suggest that with ongoing habitat management, long-term changes in group size and fledgling production will be driven primarily by group density conditions rather than changing forest age.
Fabio A. Abade dos Santos, Carina L. Carvalho, M. Conceição Peleteiro, Sofia Isabel Gabriel, Rui Patrício, João Carvalho, Mónica V. Cunha, Margarida D. Duarte
In the last decades, the European wild rabbit, particularly the Oryctolagus cuniculus algirus, a keystone species in the Iberian Peninsula ecosystems, declined severely, raising concerns from the wildlife authorities. The hunting calendar in Portugal limits sampling collection to a narrow window of few months annually. Nevertheless, governmental wildlife protection laws allow live rabbit sampling for population and sanitary evaluations. The aim of this study is to adjust blood collection protocols from the external jugular vein (EJV) described for domestic rabbits to the wild rabbit. Collection of peripheral blood is problematic in the wild rabbit given its small body size and the reduced calibre of vessels but mostly its nervous disposition and fragility. We describe in detail a procedure for EJV blood collection in 30 wild rabbits after sedation with midazolam. Emphasis is given to protocol adjustments for wild rabbit. Heart rate, respiratory rate and body temperature were assessed before sedation, after sedation but before collection and after blood collection. Sedation onset took on mean (SD) 8 ± 2 min. The technique allowed the collection at least 1 ml of blood, a satisfactory volume for routine laboratory testing. The differences observed in heart and respiratory rates before and after blood collection were not statistically significant, indicating that no cardiorespiratory interference occurred due to venepuncture. Recovery from sedation took on mean (SD) 17 ± 2 min. All animals were set free during the first hour after blood collection. This work aims to demonstrate that blood collection under sedation is a safe and feasible procedure in wild rabbits when practiced by experienced veterinarians. At no time, whatsoever, was the physiological homeostasis at risk and no injuries were inflicted on the animals. To our knowledge this report constitutes the first guided description of blood collection from the EJV in sedated O. c. algirus and the first collection of physiological parameters measured under different conditions.
Moose Alces alces is abundant throughout the boreal zone. However, in the landscapes occupied by moose the density of predators and human influence often vary considerably, as do the arrival of spring and phenology of vegetation – all crucial factors for moose, especially during their calving period.
During calving, female moose are faced with a dilemma between choosing a habitat offering high quality forage or one offering protection for the vulnerable calf. This study examined the timing of calving and habitat structure of female moose during and after calving in two areas of Finland with different predator and human densities. Data from 14 GPS-collared moose were integrated with data on landscape composition and forest structure from airborne Lidar.
In both study areas, calves were born in May and mostly in drained forests (with ditches) on peatland soils. After giving birth, females in the more human-influenced landscape moved to more fertile forests on mineral soils, whereas the females in the landscape with little human influence stayed mostly on the drained and pine-dominated peatland forests, which also had less shrub vegetation. Moose were also seen giving birth near human settlements (farms) and staying close to them (<500 m) throughout summer. Thus, females in both study areas illustrated a high degree of adaptability by selecting the highly modified drained landscapes or areas near humans for calving sites over other available landscapes.
In recent decades, wild goose populations have grown considerably. Geese forage extensively in agricultural fields leading to frequent conflicts with agricultural stakeholders and calls for effective methods to reduce economic impacts. In this study, we explored the use of handheld lasers to displace grazing barnacle geese Branta leucopsis and dark-bellied brent geese Branta bernicla from farmland pastures on the Wadden Sea island Mandø in Denmark. We evaluate the efficiency of the laser to displace geese, the resultant impact on goose usage and the derived effect on pasture vegetation height. The laser was effective in displacing geese from pastures, but range and efficiency were affected by time of day, light conditions, distance and flock size. Fields subject to laser treatments experienced seven times lower dropping densities and had a mean vegetation height that was 3.3 cm taller than control fields where geese were not exposed to lasers. While the use of laser reduced goose exploitation of experimental fields, a simple cost-benefit analysis revealed that the personnel-hours needed to find geese and operate the laser carried economic costs outweighing the potential economic benefits. We discuss the potential in displacing geese with lasers, and suggest conditions when the method may be a suitable way to reduce goose damages locally.
Assessments of terrestrial carnivore diet are often required for ecological management and conservation purposes. Analysis and identification of food remains in scats is an important method often employed for these objectives. Proportions of consumed biomass estimated from scat samples may provide an accurate approximation of the actual diet when correction factors (CFs) are used. The red fox Vulpes vulpes is a widespread generalist carnivore that includes a wide range of foods in its diet, including livestock and plays a potential role as wildlife predator. We performed controlled feeding trials with red foxes to derive CFs for eight food categories, including both from animal and vegetal origin. CFs were calculated on a daily basis as the ratio between eaten fresh mass and total dry mass of the resulting scats. Red foxes consumed daily 615 ± 19 g (mean ± SE) of food and produced 6.4 ± 0.3 scats weighing 31 ± 1.2 g. The CFs varied significantly among food types, with the lowest values for partridges Alectoris rufa (CF = 12.5 ± 0.7) and the highest for red deer Cervus elaphus (CF = 47.3 ± 7.3), increasing linearly and significantly in relation to the individual body mass for the animal food types. CF precision was low for deer, fruit and hare Lepus granatensis, but more importantly, the CFs differed considerably among food types. We recommend considering intra-food variability when using CFs for estimating proportions of ingested biomass in studies of generalist carnivores such as red fox as a better support for management and conservation decisions.
The caracal Caracal caracal is the largest of Africa's small felids (<20 kg). Across much of Africa, particularly where larger predators have been extirpated, caracal are one of the main carnivores contributing to livestock predation. Caracal dietary studies are outdated, typically have small sample sizes and have mainly relied on scat analysis. We used a combination of scat analysis (n = 250 scats) and GPS cluster visitation (n = 458 clusters visited; n = 91 clusters with feeding events) to estimate caracal diet in South Africa's Succulent Karoo, a global biodiversity hotspot. Based on both methods, rock hyrax Procavia capensis was the caracal's main prey. Small mammals accounted for 25.3% of total biomass consumed by caracal using scat analysis, however, were absent based on GPS cluster investigations. Domestic sheep Ovis aries biomass consumed was much higher (59.5%) when inferred from GPS cluster visitation than from scats (5%). Wild medium-to-large mammalian prey had little variation between the two methods. GPS telemetry did not enable detection of small prey (<1 kg) and possibly over-represented large prey items, including livestock. Scat analysis provided a broader representation of caracal diet, but scat investigations could have underestimated larger prey since caracals ingest only small amounts of hair from large-bodied animals. We recommend a combination of GPS cluster visitation and scat analysis to determine the diet of caracal and other mesocarnivores across a range of prey sizes.
Knowledge of patterns of occupancy is crucial for planning sound biological management and for identifying areas which require paramount conservation attention. The European wildcat Felis silvestris is an elusive carnivore and is classified as ‘least concern' on the IUCN red list, but with a decreasing population trend in some areas. Sicily hosts a peculiar wildcat population, which deserves conservation and management actions, due to its isolation from the mainland. Patterns of occupancy for wildcats are unknown in Italy, and especially in Sicily. We aimed to identify which ecological drivers determined wildcat occurrence on Mt Etna and to provide conservation actions to promote the wildcats’ long-term survival in this peculiar environment. The genetic identity of the wildcat population was confirmed through a scat-collection which detected 22 different wildcat individuals. We analysed wildcat detections collected by 91 cameras using an occupancy frame work to assess which covariates influenced the detection (p) and the occupancy (ψ) estimates. We recorded 70 detections of the target species from 38 cameras within 3377 trap-days. Wildcat detection was positively influenced by the distance to the major paved roads and negatively affected by the presence of humans. Wildcat occupancy was positively associated with mixed forest and negatively influenced by pine forest, fragmentation of mixed forest and altitude. A spatially explicit predicted occupancy map, validated using an independent dataset of wildcat presence records, showed that higher occupancy estimates were scattered, mainly located on the north face and at lower altitude. Habitat fragmentation has been claimed as a significant threat for the wildcat and this is the first study that has ascertained this as a limiting factor for wildcat occurrence. Conservation actions should promote interconnectivity between areas with high predicted wildcat occupancy while minimising the loss of habitat.
The anthropic transformation of the landscape has brought the arrival of novel ecosystems. Since these ecosystems will likely become increasingly common in the future it is important to know if they can provide food for wildlife. Here we test whether European otters Lutra lutra can have high foraging success in human-made reservoirs. Rhythms of daily activity were studied in a small (365 ha) and shallow (6–15 m) reservoir in NW Spain in which otters show diurnal activity and can be observed directly when foraging. We studied time of permanence in the water and fish catch rate during the period in which water levels were kept artificially low (autumn–winter 2015, 2016 and 2017). Results indicate that otters had at least two peaks of diurnal activity (from 10:00 to 11:00 a.m. far from sunrise and from 06:00 to 07:00 p.m. immediately before sunset). Otters spent an average of 74 min (54–94, 95% CI) in the water foraging daily, and had a minimum fish catch rate of ca 600 g h–1 of small fish. According to a pre-existing theoretical model, otters eating at that rate can satisfy their daily energy requirements with just 1.5 h of daily foraging activity, what roughly coincides with the upper confidence limit of the parameter estimate. When considering as well the capture of large fish otters obtained ca 850 g of fish per day in only 1.2 h in the water. Otters in the reservoir satisfy their daily requirements in autumn–winter with the same time investment than Shetland Island otters foraging during the day on marine fish during the summer. This coincidence is most likely due to the fact that winter water temperature in our study site is similar to that in the Shetland Islands in summer.
Peter S. Coates, Gregory T. Wann, Gifford L. Gillette, Mark A. Ricca, Brian G. Prochazka, John P. Severson, Katie M. Andrle, Shawn P. Espinosa, Michael L. Casazza, David J. Delehanty
Counts of grouse present at leks (breeding grounds) during spring are widely used to monitor population numbers and assess trends. However, only a proportion of birds available to count are detected resulting in a biased population index. We designed a study using an aerial integrated infrared imaging system (AIRIS) and experimental pseudo-leks to quantify sightability (proportion of birds detected) of conventional ground-based visual (GBV) surveys for greater sage-grouse Centrocercus urophasianus. Specifically, we calibrated AIRIS at pseudo-leks composed of known numbers of captively-raised birds, primarily ring-necked pheasant Phasianus colchicus. We then carried out AIRIS and GBV surveys, simultaneously, on nearby sage-grouse leks, allowing us to model AIRIS and GBV sightability. AIRIS detected ∼93% of birds on pseudo-leks while GBV detected ∼86% of sage-grouse on leks. Thus, the ground count observation error was –14% from the ‘true' number of male sage-grouse attending the leks. We also found sagebrush cover decreased sightability for GBV counts but did not influence sightability by AIRIS. Because standard GBV protocols typically make repeated counts of sage-grouse in a single morning, we also modeled repeated GBV counts using N-mixture models and found an 88% sightability, which was nearly the same as GBV sightability from the AIRIS analysis. This suggests that the use of repeated morning counts can potentially account for imperfect detection in the standard GBV surveys currently implemented. We also provide generalized correction values that could be employed by resource managers using either GBV or AIRIS to better estimate ‘true’ numbers of sage-grouse attending leks within similar environments to this study. The findings and interpretation presented can help guide effective monitoring protocols that account for observation error and improve accuracy of data used for population trend and abundance estimation.
In Eurasia, forest grouse have been declining throughout most of their geographical ranges. Presumably, poor recruitment due to high predation of nests and chicks is one important causal factor. In a southeastern Norwegian forested landscape (Fjella), we provided diversionary food to predators – directed mainly at the red fox Vulpes vulpes – during the nesting and early brood season of capercaillie Tetrao urogallus and black grouse T. tetrix in three nearby areas. In Eidsberg, where populations were censused during 33 years (1985–2017), food was provided during the last 22 years. In two other areas, a six-year experimental program was conducted (2003–2008) by providing food in one area for three years, then switching feeding to the other area for three years. During May and June, 10 kg of food – mainly moose offal and ungulate carcasses – was deposited at feeding stations once a week. In Eidsberg, black grouse breeding success increased by 43% after feeding was initiated, mainly due to larger brood sizes. In capercaillie, overall breeding success tended to increase, solely due to more females successfully rearing chicks. In the experimental areas, feeding increased breeding success an estimated 57% in black grouse. In capercaillie there was also a tendency for a positive effect, but sample sizes were too small for statistical inference. No increases were detected in adult birds. However, in capercaillie, increased breeding success after feeding led to a significant skew in sex ratio favouring males. A similar tendency in black grouse suggested source–sink dynamics and a net loss of young females during natal dispersal. We conclude that diversionary feeding of foxes in spring and early summer might be a feasible management tool to increase the reproductive output in local grouse populations, but that it needs to be implemented on a larger scale in order to improve breeding numbers.
Forage quality is rarely the focus of studies on grouse performance. The plant stress hypothesis predicts that the protein digestibility of a focal food plant for grouse in Norway, the bilberry Vaccinium myrtillus should be highest after a peak in seed production. Protein digestibility may also be affected positively by cosmic ray (muon) fluxes, which fluctuate with the 9.3-year lunar nodal phase cycle, and negatively by high temperatures in the preceding summers. The annual change (first difference) in ln-transformed black grouse Tetrao tetrix and capercaillie T. urogallus hunting statistic indices from southern Norway 1999–2017 was positively related to the mean June temperature, which is assumed to have a direct positive impact on chick survival. In multiple regression models, there was also a positive relationship with the seed production of bilberry in the preceding year, the lunar nodal phase index with a two-year time lag, and a negative relationship with the combined mean June–September temperature of the two preceding years. Small rodent numbers did not contribute significantly in these models. In further monitoring of grouse populations, the seed production of bilberry or other important food plants should also be recorded.
Amphibian nutrition has been highlighted as one of the disciplines requiring more investigation to support ex situ conservation programs. Specifically, anuran metabolism related to dietary nutrients is not yet investigated in detail. Thirty (n = 30) free-range frogs from four families (Telmatobiidae, Hylidae, Leptodactylidae, Bufonidae) were collected in Bolivia, and opportunistic blood samples were drawn to determine acylcarnitines and amino acid profiles in order to evaluate metabolic activity. The overall profiles showed Telmatobiidae with higher numerical values of amino acids, while comparison with Hylidae displayed differences (p < 0.05) in metabolites related to amino acid catabolism, suggesting specific ketogenic pathways in Telmatobiidae as an adaptation to its extreme environmental (hypoxic) conditions. Multivariate analysis demonstrated both lipids and amino acids as the main forces in frog energy metabolism, confirming the carnivorous nature of anurans. Pathways detecting free carnitine and long chain acylcarnitines driving fat metabolism, as well as protein-derived utilisation of amino acid catabolites documented glucose sparing and energy production through both proteinogenic and ketogenic routes. Moreover, malonyl carnitine is suggested to play a role as a modulator of food intake and feeding status of frogs.
European ungulates such as the roe deer face seasonally varying climatic conditions as well as food availability and quality. In some European countries, including Austria, it is common practice to provide game animals with supplemental feeding in winter. In this study we investigated if supplemental feeding significantly affects the composition of the bacterial rumen community. The rumen microbial composition of eight adult female roe deer was analysed by Illumina MiSeq 16S rRNA gene amplicon sequencing. Animals from a study area with supplemental feeding sites were compared to individuals relying on natural feed. Furthermore, the microbial community composition of different ruminal compartments (liquid phase, solid phase and wall) was compared. Our results revealed a significant qualitative difference between the microbiota composition of the two populations studied. Easily fermentable supplemental feeding promoted the proliferation of phylotypes correlated with conditions of acidosis in domestic ruminants, suggesting a possible similar adaptation and a hypothetical negative effect on health status also in roe deer. The results furthermore confirmed that in roe deer, like in other ruminant species, the most represented phyla are Firmicutes (63.2%) and Bacteroidetes (23.5%), and that the ruminal microenvironments influence the microbial community composition, with the lowest species richness and variation in the epimural microbiota.
The endangered Amur tiger Panthera tigris altaica is confined primarily to a narrow area along the border with Russia in northeast China. Little is known about the foraging strategies of this small subpopulation in Hunchun Nature Reserve on the Chinese side of the border; at this location, the prey base and land use patterns are distinctly different from those in the larger population of the Sikhote-Alin Mountains of Russia. Using dietary analysis of scats and camera-trapping data from Hunchun Nature Reserve, we assessed spatiotemporal overlap of tigers and their prey and identified prey selection patterns to enhance understanding of the ecological requirements of tigers in northeast China. Results indicated that wild prey constituted 94.9% of the total biomass consumed by tigers; domestic livestock represented 5.1% of the diet. Two species, wild boar Sus scrofa and sika deer Cervus nippon, collectively represented 83% of the biomass consumed by tigers. Despite lower spatial overlap of tigers and wild boar compared to tigers and sika deer, tigers preferentially preyed on boar, likely facilitated by high temporal overlap in activity patterns. Tigers exhibit significant spatial overlap with sika deer, likely favoring a high level of tiger predation on this large-sized ungulate. However, tigers did not preferred roe deer Capreolus pygargus and showed a low spatial overlap with roe deer. Overall, our results suggest that tiger prey selection is determined by prey body size and also overlap in tiger and prey use of time or space. Also, we suggest that strategies designed to minimize livestock forays into forested lands may be important for decreasing the livestock depredation by tigers. This study offers a framework to simultaneously integrate food habit analysis with the distribution of predators and prey through time and space to provide a comprehensive understanding of foraging strategies of large carnivores.
KEYWORDS: anthropogenic impact, ecosystem health, faecal glucocorticoid metabolite, land use types, Micaelamys namaquensis, non-invasive stress hormone monitoring, South Africa
Stress in animals has been linked to behavioural and physiological changes in response to environmental, social and anthropogenic stimuli. Hence, stress-related responses in animals, especially in rodents, have been used as biological indicators of ecosystem health. This study aimed to establish an enzyme immunoassay (EIA) for monitoring adrenocortical activity in free-ranging Namaqua rock mice Micaelamys namaquensis (Rodentia: Muridae) using faeces as a prerequisite for assessing the effects of anthropogenic land use and season on faecal glucocorticoid metabolite (fGCM) concentration. Rodents were live-trapped seasonally across four land use types: an agricultural crop farm, an agricultural livestock farm, a human-populated site and a nature reserve; all situated in Limpopo Province, South Africa. Determined fGCM concentrations from capture and recapture events were used for biologically validating an EIA detecting steroids with a 5α-3β-11β-diol structure. Recapturing resulted in a significant overall 40% elevation of individual fGCM concentrations demonstrating the effectiveness of the chosen EIA to reliably detect glucocorticoid output in the study species. Neither land use type nor season affected fGCM concentrations in the species, suggesting that land use and season-related environmental changes do not necessarily act as stressors for M. namaquensis, presumably due to their adaptive and resilient nature. Such species can be used to identify ecosystems affected by human-mediated disturbances and allow insights into the management and restoration of these threatened ecosystems and their associated species.
Wild boar are currently one of the most widespread mammals of the world and in many regions populations keep expanding. In Flanders (Belgium), the wild boar has returned since 2006 after almost half a century of absence and numbers are increasing fast. The Flemish landscape is severely fragmented and is one of the most densely populated areas in the world. Understanding the relationship between landscape structures and species biology is the basis of landscape ecology and increases the understanding of factors driving habitat use, recolonisation and expansion. We conducted a landscape genetics study to identify factors driving wild boar expansion in Flanders. A total of 838 DNA-samples collected from the wild boar hunting bag between 2007 and 2016 were genotyped for 140 single nucleotide polymorphisms (SNPs). We show that the wild boar population expansion started from two local gene pools while staying relatively genetically distinct, though with some admixture. A third gene pool emerged around 2013 in the northwest coming from the Netherlands and Germany. The landscape genetic analysis revealed that the main factors explaining the spatial genetic pattern are isolation by distance and forest cover which influenced gene flow positively. Forest fragmentation had no significant effect on genetic distances. As human–wildlife conflicts are increasing in line with wild boars' expanding distribution range, understanding factors driving expansion during recolonisation is essential for assessing the future dispersal of wild boar in Flanders. With a better insight in future dispersal, it will be possible to conduct risk assessments which target more efficient management actions to limit human–wildlife conflicts.
A growing body of evidence suggests that hunter effort varies temporally and spatially, affecting game populations in unexpected ways. We set out to identify sources of variation in the spatial distribution of hunter effort by ring-necked pheasant Phasianus colchicus hunters during two time periods representing different spatial decisions: where to access a hunting location at the start of a hunt and where to hunt within it for the duration of the hunt. Pheasant hunters used direct and indirect information about the availability and accessibility of pheasants to make spatial decisions throughout their hunts, but the sources of information used at the beginning of hunts differed from those used for the duration of hunts. Hunter access point effort at the start of hunts was positively associated with proximity to public access signs and declined near marked safety zones around occupied structures and livestock, indicating that hunters responded to the spatial distribution and information content of public access infrastructure. Hunter effort within fields for the duration of hunts was positively related to predicted pheasant habitat use and negatively associated with correlates of physical exertion and increasing distance from field edges. Our findings indicate that hunters in the field are making spatial decisions in response to information about public land access, their own physical state, and perceived opportunity to encounter pheasants. Our results further suggest managers may be able to optimize public lands for wildlife habitat and recreational value without imposing new regulations by managing the information provided to hunters.
Abundance estimators are often evaluated with simulations, or by comparing estimates to populations of known size. Advances in noninvasive genetic sampling have fueled an increase in the use of noninvasive genetic sampling-based capture–recapture. However, when working with free-ranging populations of unknown size, managers often lack data necessary to select the appropriate estimator. This leads to uncertainty regarding how choice of estimator or sampling design influence estimates, and managers may select estimators based on funding or logistical constraints. Alternatively, comparing estimates from multiple estimators can provide managers with greater confidence in estimates, or highlight potential differences. We used noninvasive genetic sampling to estimate the abundance of free-ranging kit foxes Vulpes macrotis and coyotes Canis latrans. We generated estimates of abundance with two non-spatial likelihood-based estimators: 1) robust design Huggins capture–recapture models and 2) single-occasion capture with replacement (CAPWIRE) models. We compared these with recently published estimates derived from spatially explicit capture–recapture (SECR) models. For both species, estimates from Huggins models were generally lower than those from SECR. Abundance estimates from CAPWIRE, which was developed specifically for noninvasive genetic sampling and generates estimates from a single sampling occasion, tended to be biased low with high precision. Our results suggest that choice of estimator and sampling design can significantly influence estimates, and that the relationship between estimators varied between species. Our results further suggest that single-occasion sampling often employed with CAPWIRE abundance estimation may produce biased results and be inappropriate for species requiring dispersed sampling strategies.
Understanding how top–down and bottom–up effects influence population dynamics of ungulates is essential for effective management and conservation, and there is an emerging consensus that forage productivity and quality interact with predation to influence survival. From 2009 to 2013, we captured and monitored 135 neonatal black-tailed deer Odocoileus hemionus columbianus in coastal California to study possible interactions between forage and predation on survival. We estimated seasonal and annual survival rates, assessed the cause of all mortalities (n = 93), measured available forage and diet quality, estimated relative abundances of predators on summer range each year, and used remote sensing to quantify habitat types on winter range. We evaluated the relationship between fawn survival and environmental covariates with cumulative incidence and proportional hazards functions. Summer survival rates averaged 0.40 (SE = 0.05) across all years and the mean annual survival rate was 0.26 (SE = 0.04). We found that most juvenile mortality resulted from predation during summer, and spatial differences in summer survival persisted until recruitment. Variation in mortality risk from all causes was related to the birth weight of juveniles and available oak forage but not predator abundance. The risk of black bear predation, the single largest cause of mortality, was unrelated to birth weight and showed an interaction between bear abundance and the amount of oak forage. Additionally, the good body condition of adult females in spring and a lack of relationship between mortality risk and variation in deer density did not provide evidence for purely bottom–up limitation. Rather our results provide evidence that both bottom–up and top–down effects were influencing fawn survival in this declining population, and that predator identity and the timing of mortality affected the impact of predation.
For many species, burrowing is used for a variety of purposes, such as finding food, sheltering from elements and predators, or raising offspring. For threatened species, differentiating among burrow types allows effective conservation efforts, and provides insight into habitat attributes needed at different stages in their life-history. This study investigated whether burrow characteristics for the North American badger Taxidea taxus allowed discrimination among summer, winter and natal burrows, and whether these characteristics reflected different requirements by the animals. Radio-telemetry was used to monitor badgers and classify burrows based on seasonal occupancy. Characteristics relating to thermal and security cover, along with features that could correlate with prolonged usage, were measured across winter, natal and summer burrows. Winter and natal burrows showed greater vegetation cover than summer burrows, potentially indicating increased thermal protection and predator avoidance. However, for winter burrows, greater vegetation cover did not translate into warmer, winter subterranean temperatures compared to summer burrows. Winter and natal burrows also had larger soil fans and, in the case of natal burrows, also had more entrances than summer burrows. These features may be indicative of prolonged usage. All told, it appeared summer burrows were distinguishable from winter and natal burrows based on the dimensions and construction of the burrow, location and surrounding vegetation. However, because badgers are capable of modifying their environment (including existing burrows) it is difficult to make precise predictions of where certain burrow types will occur. Still, the results of this study allow protection efforts or other management considerations to be apportioned more effectively among different burrow types. Comparable work is needed in other regions to understand how burrow characteristics spatially vary in importance.
Individuals in substandard physical condition are predicted to be more vulnerable to predation. Support for this prediction is inconsistent partly as a result of differences across systems in the life histories of predator and prey species. Our objective was to examine the physical condition of woodland caribou Rangifer tarandus caribou calves depredated by two predators with different life histories in Newfoundland, Canada. Black bears Ursus americanus are capable of chasing calves at high speeds over short distances and primarily prey on calves <1 month of age. Coyotes Canis latrans are cursorial predators that pursue prey over longer distances, which is expected to result in the selection of substandard individuals. We hypothesized that 1) black bears will kill calves in substandard physical condition, while 2) coyotes will kill calves from across the distribution of individual conditions. We used mitochondrial DNA species identification tests to assign predator species to calf mortalities. We then used molecular identifications and field observations to build a predictive model using generalized boosted trees to predict the predator species where a molecular identification was unavailable. We tested our hypotheses using Cox proportional hazards models under a competing risks framework. Bears killed younger calves and lighter calves, while coyotes killed heavier calves. Coyotes also killed more late-born calves, which might suggest prey switching as calves become more abundant later in the season. Our findings suggest that the physical constraints of predators play a greater role than predator hunting strategies in this system, but other processes are likely influential. The tendency for coyotes to kill heavier calves might result from sustained coyote predation over time, following the removal by black bears of lighter calves during their first month of age. This research illuminates the complexity of predator–prey interactions in Newfoundland and highlights an important source of variability for predator–prey systems.
Grasslands are inherently dynamic systems having developed with frequent disturbance from fire and grazing that varies in space and time to create heterogeneity. Today, many management practices emphasize the even use of grasslands by grazers and either no fire or uniform fires, resulting in grasslands that lack the variability in plant structure and composition to support the entire suite of grassland biodiversity. Previous research has suggested that the reintroduction of variable disturbance may be among the best conservation strategies for grassland birds, as these practices promote diversity and abundance of many species. However, the reintroduction of heterogeneity is taking place in the context of the continued development of grasslands for energy production, and the utility of heterogeneity based management practices may decline in fragmented landscapes. We investigated how fragmentation from oil and gas may constrain management efforts to promote biodiversity by evaluating changes in bird abundance with distance from roads and conventional oil wells across a gradient of times since fire. We found that time since fire was the primary driver of grassland bird distribution, with dickcissels, eastern meadowlark and grasshopper sparrows occurring in all vegetation patches, while Henslow's sparrows primarily occurred in patches that were greater than 13 months post-fire and upland sandpipers were mostly detected in recent burns. Further, Henslow's sparrows avoided oil wells for considerable distances, while eastern meadowlark was more abundant in areas close to oil wells in vegetation patches that were one-year post-fire. Grasshopper sparrows avoided roads in recent burns and dickcissels, and eastern meadowlarks were attracted to roads in patches that were recently burned and one-year post-fire, respectively. The restoration of heterogeneous fire regimes will benefit bird communities by creating variable vegetation structure that can support multiple grassland bird species; however, energy development has the potential to fragment grasslands for some species.
In western Europe, the majority of wild goose populations have increased exponentially over the last decades. Such increase is the source of many socio–ecological conflicts. The need for coordinated management actions to handle the goose-related conflicts at the European scale has led to the establishment of a specific European Goose Management Platform (EGMP) under the auspices of the Agreement on the Conservation of African–Eurasian Migratory Waterbirds (AEWA). The northwest/south-west (NW/SW) European population of greylag goose Anser anser has been considered as a priority concern, and an AEWA international single species management plan has been recently adopted. Because of the complex structure of the greylag goose population (e.g. spatial differences in migration strategies), and management (e.g. different hunting schemes among the range states), delineation of management units (MUs) based on goose movement characteristics was deemed necessary to further implement effective management actions. Based on neckband marking in various breeding regions and subsequent resighting locations, we conducted spatio–temporal analysis based on kernel methods to infer spatio–temporal and migratory movements of greylag geese in the NW/SW European flyway. The results highlight the existence of contrasted migratory behaviour, dispersal patterns and phenology within the flyway. From these results three international management units could be delineated. The first MU would include migratory birds from Norway. Birds from breeding grounds in Sweden and Denmark would represent the second MU. Finally, a third central MU was delineated, including primarily breeding birds from the Netherlands and northwestern Germany, which do not show migratory behaviour at the flyway scale. The delineation of these MUs has to be considered within an adaptive process, and future studies will enable a refinement of the definition of such units in order to continuously improve the efficiency of management plans.
Legitimacy is a prerequisite of sustainable forms of governance. Existing structures and functions of large carnivore governance have often yielded legitimacy deficits. In northeast North Carolina, USA, recovery of the critically endangered red wolf Canis rufus suffers from a legitimacy deficit, chiefly among its critics. This article operationalizes legitimacy and investigates its predictors in the North Carolina red wolf case. We developed a framework that explores three dimensions of legitimacy (input, output and throughput) to simplify the concept within the red wolf recovery and management system. Our challenge was to identify the relevant predictors of legitimacy in totality to improve governance. We analyzed 2577 survey responses from citizens owning property or living within the red wolf recovery area and used multilevel modeling to analyze the relationships between contextual or individual variables and perceived legitimacy. Results revealed that a higher number of red wolf mortalities in a respondent's county may be an ecological predictor of perceived lower legitimacy. Results also indicate that women, formally educated, and smaller parcel-owning landowners were more likely to find red wolf recovery legitimate. Tolerance of red wolves, normative ethics about red wolf recovery, and the instrumental value of wolves were also strong predictors of legitimacy. We conclude that situating legitimacy at the center of a nested social–ecological system may more accurately reveal expressions of its core elements, criteria, or sources in order to identify and treat the pathologies of large carnivore governance.
Hunting, including drive hunts, can be considered as a predation process. Although drive hunts are spatially and temporally well defined, the scale at which the hunting risk triggers anti-predator responses of prey remains poorly documented. The present study aims at 1) characterizing the delayed movement responses of female red deer Cervus elaphus to hunters and 2) understanding the main environmental determinants modulating these post-disturbance responses at the individual level. We hypothesized that red deer alter their movement behaviour for several days after a drive hunt by increasing their speed and exploring more space. Then, we predicted that individuals close to the hunting area would exhibit stronger responses (i.e. higher speed and larger home range size) than individuals located further away. We also expected topographic obstacles and vegetation cover to reduce the magnitude of the post-disturbance responses. We used GPS data from a large dataset collected on 91 female red deer in the National Hunting and Wildlife Reserve of La Petite Pierre (France), between 2004 and 2018. Each year, drive hunts are conducted by about 43 hunters and 6 dogs, once a week from October to February. Our results suggest that, over a 72-h period after a drive hunt, female red deer could show two contrasting strategies: 1) flight-type movements (i.e. higher maximum speed) associated with more space explored due to a temporary avoidance of the disturbed area and 2) lower movements to avoid detection and contacts with hunters. These two delayed responses are situation-specific, depending on risk proximity, landscape features, hunting conditions and individual characteristics. This study highlights that ungulate management using a ‘hunting for fear’ approach may be adjusted considering spatial and temporal scales of the effects of drive hunts on red deer movement patterns.
Low ungulate density can be a factor in limiting tiger populations, so to better manage tiger reserves one must be able assess if this is the case or if other factors might be more important. Here, we quantify ungulate density in a tiger reserve in India, compare it to other reserves, and estimate the tiger carrying capacity in order to assess this reserve can support a viable tiger population. Specifically, we studied the Similipal Tiger Reserve (STR), Odisha, India, from 2011 to 2014. The line transect method was used to estimate population density of available major ungulate prey species, i.e. sambar Rusa unicolor, wild pig Sus scrofa, barking deer Muntiacus muntjac, chital Axis axis and mouse deer Moschiola indica. A remarkable increase in ungulate prey density was noted in the intensive study area over the study period from 4.3 animals per km2 in the pre-monsoon season of 2011 to 28.9 animals per km2 in the post-monsoon season of 2014. This estimated ungulate density is very low compared to other tiger reserves of India. Density figures of ungulates when multiplied with the average weight of the respective species gave a biomass density of 1599.4 kg km-2. This data was then used in two published empirical models to obtain estimates of tiger carrying capacity in STR. We used two empirical models from the published literature and concluded that the tiger carrying capacity of Similipal Tiger Reserve ranges between 1.3 and 3.8 tigers per 100 km2, much lower than our current estimates of tiger density. This suggests that the tiger population is below carrying capacity or that the estimated tiger population in critical tiger habitat falls below the threshold number. We suggest that the creation of large meadows for herbivores and the establishment of suitable fenced areas to augment breeding of the prey species chital and sambar are necessary to support a viable tiger population in the Similipal Tiger Reserve.
Restoration of top carnivore populations, such as gray wolves, may have many cascading effects on the ecosystems they inhabit. In many areas of North America without wolves, coyotes become dominant predators and can suppress the abundance of smaller carnivores such as foxes. Ecological theory and studies would suggest that recovering wolf populations could benefit foxes by limiting the abundance of coyotes and thus releasing foxes from the suppressive effects of coyotes. Using long-term (38 year) monitoring data, we evaluated the effects of recovering wolf populations on the abundance of coyotes and foxes in two regions of Wisconsin (USA). Overall, we found no evidence to support the hypothesis that increasing wolf populations limited coyote abundance, and instead found limited evidence that intrinsic density-dependence was more important to structuring coyote population growth based on model selection results. However, we did find some evidence to suggest that coyote populations are limiting fox population growth in one of our study regions. That wolves do not appear to limit coyote populations in Wisconsin could be the result of changing prey abundance and landscape configuration that favor coyotes, or the comparatively low wolf densities in Wisconsin as compared to areas where wolf effects on coyotes have been documented. We suggest that future research directly address the interactions among canids in the Great Lakes region, as there is large potential for cascading ecological effects as abundance of these species changes over time and space.
To better understand the mechanisms driving the distribution of a threatened carnivore, wolverine Gulo gulo, in the southern Columbia Mountains, we contrasted four hypotheses; climate, food, human disturbance and trapping harvest. We used non-invasive hair snagging methods to examine wolverine occupancy with respect to these factors, collectively and by sex, at a 5 km radius scale around sampling sites and at a larger 10 km radius to evaluate consistency over changes in scale. For all analyses our top models included food and human disturbance. Of the four food items examined; caribou Rangifer tarandus, mountain goat Oreamnos americanus, moose Alces alces and hoary marmot Marmota caligata, wolverine occurrence was most closely related to hoary marmot habitat. With regards to human disturbance, we documented a negative association with forestry road density and a positive association with protected areas. The importance of climate was low compared to the food and disturbance hypotheses. Somewhat surprisingly, recent harvest was positively associated with subsequent wolverine presence. Our top 10 km scale models were similar to the 5 km scale, but with a stronger positive link to caribou distribution. We show that marmot habitat is important to wolverine in winter and suggest that management actions for conservation prioritize factors related to female occurrence, as these were more clearly defined than male. We demonstrate that human disturbance is a major driver of wolverine distribution. Protected areas appear to be providing secure habitat, and reducing road density or mechanized use of roads in winter should be considered for species conservation. A positive spatial relationship with recent harvest, in the context of a heavily harvested population, suggests that harvest data alone may not be useful in detecting population declines.
Predation by mammalian and avian predators is an important cause of mortality in grouse species during all life stages and has been linked to impaired reproductive performance. Some grouse species are important game birds, but many populations are red-listed at the national level. In consequence, predator control is often conducted as a grouse conservation measure, but remains a contentious issue, also because evidence of its effectiveness is lacking. Here, we review the evidence on predation as a limiting factor for grouse populations and perform a quantitative assessment of the effectiveness of predator control to benefit grouse population parameters. We found support that grouse populations appear to be typically limited by their predators. Predator control was associated with an overall positive effect size on grouse population parameters (i.e. mean of 1.43 times the reference value, 95% CI of 1.22–1.68). We found positive effect sizes for most population parameters (reproductive success; adult abundance and survival), but not all (brood size, nest success). Our results suggest that predator control is likely to achieve short-term conservation benefits for grouse if well-designed and rigorously conducted. We suspect, however, that the majority of control programmes conducted for conservation do not meet this standard.
Studies on dietary habits and niche overlap of sympatric carnivore species can be vital for their conservation. They can reveal the potential level of inter-specific competition and prey species overlap, thus highlighting species specific conservation requirements. We investigated diet composition of two such sympatric carnivore species Asiatic jackal Canis aureus and the Kashmir hill fox Vulpes vulpes grifithii in and around Pir Lasura National Park, in northeastern Himalayan region of Pakistan by using fecal analysis after confirming the carnivore species by genetic analyses. The scats of the two carnivores were collected during four different seasons of the year and analyzed in the laboratory. Results revealed sixteen prey species in the diet of Asiatic jackal and 21 species in the diet of the Kashmir hill fox. For Asiatic jackal, wild prey contributed approximately 18%, whereas 60% of the diet comprised of domestic prey. For Kashmir hill fox, the wild prey consumption was approximately 18%, while consumption of domestic prey was 51% and plants contributed 28%. Niche breadth of the Asiatic jackal was broader (0.78) compared to Kashmir hill fox (0.31). Niche overlap between these two sympatric carnivores was found to be a rather high 0.81.
Although the proliferation of the wild boar in Europe makes capturing and handling necessary for both management and research, the behavioural responses of this species to capture are still unknown. We evaluated how capture affects wild boar behaviour during the first 30 days after the release, focusing on the animals' total activity, mobility and activity rhythms and their variation in response to different drug mixtures used for sedation. Low levels of activity and mobility characterized the first 10 post-capture days. After this period, a gradual restoring of stable levels occurred. Wild boar captured by using different drug mixtures exhibited slightly different patterns of activity depression. We also showed capture to produce a partial effect on wild boar behavioural rhythmicity. Our findings highlight the case study variability of the capture effect and offer useful insights into several conservation and management implications.
Research and management programs of wild animal populations often require intensive field actions, which make direct interventions on animals such as capture, immobilization and manipulation, frequently necessary. Such events, however, could induce a stress response causing physiological and behavioural alterations in the individuals. Knowing the impact of these practices in the post-release phase is of crucial importance when studying the spatial behaviour of wild species. Our study aimed to investigate the potential effect of narcosis and application of GPS collars on 17 red deer Cervus elaphus hinds living in a mountainous area in northern Apennine, Italy. We conducted the analysis at a temporal scale of 45 days after release, in order to assess the response of animals in terms of changes in movement rates, distance from the barycentre of their positions and distance from the capture sites. We then compared habitat selection between the period of disturbance and the following days. This work represents the first study of the behavioural responses of wild red deer to capture and handling procedures. We showed that these operations significantly affect the spatial behaviour of hinds by inducing a short-term increase in movement rates and by keeping the animals away from the centre of their activity, for a period no longer than 10 days. The habitat selection analysis remarked a tendency to escape from human disturbance, by avoiding hunting sites and anthropized locations in favour of forest cover. Red deer hinds thus, seem to cope with stressful events and disturbance by adopting a flight behaviour, which includes moving away from the capture area and seeking refuges. The differences highlighted between the ‘stressful’ period and the following one, showed that such modifications persist for a limited time frame and suggested that this capture method is unlikely to lead to permanent alterations of behaviour.
High numbers of red deer Cervus elaphus pose a challenge for natural forests because of their high browsing intensities, especially during winter months. To mitigate this human–wildlife conflict, conservation management in central Europe involves luring red deer into fenced winter-feeding sites. The supplementary food provided in these so-called winter enclosures strongly differs from the natural diet of red deer. Dietary shifts, however, can lead to an imbalance of the gut microbiota, which could promote bacterial pathogens. Moreover, increased inter-individual contact in winter enclosures enhances the exchange of symbiotic but also pathogenic bacteria. In this study, we used high-throughput sequencing of the 16S rRNA gene in fecal samples of red deer inhabiting the Bavarian Forest National Park to investigate differences in the gut bacterial microbiota between individuals in winter enclosures and individuals that ranged freely in the forests in winter. We also investigated the occurrence of potential zoonotic bacterial pathogens in both study groups. Our results revealed that proportions of bacterial taxa, alpha- and beta-diversities, and relative abundances of amplicon sequence variants in the gut bacterial microbiota of the two groups differed. These differences were attributed to the enrichment of bacterial taxa involved in the digestion of the supplementary food and to different natural diets consumed before entering the winter enclosures. We detected sequences with high similarities to known red deer pathogens in both study groups, but their relative abundances were low, which suggests that the population of red deer of the Bavarian Forest National Park is healthy.
Collar-mounted monitoring devices for collecting behavioural or positional data (e.g. sound recorders, accelerometers, GPS, VHF) are increasingly used in wildlife research. Although these tools represent an improvement in terms of data quality, they require capturing animals. Using remotely releasable collars allows for reducing the number of captures by half; however, currently this technology is primarily available for large mammals. Here, we present a locking mechanism design that is remotely releasable and light enough (22 g) for medium-sized mammals (>1 kg), can run in low-power mode for years, is reusable directly after recharge, and has a material cost of less than €50. An Android application operates this mechanism over a Bluetooth connection. We developed custom-purpose software for both the locking mechanism and the Android application. We tested two collars equipped with this locking mechanism in field-like conditions on two ring-tailed lemurs Lemur catta. The release mechanism has an operational range of 10–50 m and can run in active mode (allowing remote release) for several hours. Implementation of the presented release mechanism for collars on medium-sized mammals provides a low-cost solution to reduce the number of captures. We demonstrate that some low-cost technical improvements of tools used for studying wildlife can have significant effects on reducing the stress experienced by animals during capture. Detailed description of this new mechanism design provides a starting-block for potential adaptations for a broader range of species.
The understory vegetation of the Eurasian boreal forest is dominated by several ericaceous species (e.g. bilberry Vaccinium myrtillus). These species invest large amounts of energy in their sexual reproduction by producing seed-containing berries, which are apparent adaptations for endozoochory. Their seedlings are, however, almost never found in the wild, and they reproduce virtually exclusively through clones. Brown bears Ursus arctos consume enormous amounts of ericaceous berries (predominantly bilberry in central Scandinavia) during hyperphagia, and may facilitate sexual reproduction in such species. If ericaceous species would benefit from endozoochory by brown bears, one would predict that endozoochory would have no negative impacts on germination. We experimentally evaluated this prediction using germination trials under controlled conditions of bilberry seeds that were 1) extracted from brown bear feces, 2) extracted from ripe berries and 3) contained in berries. Using time-to-event analyses, we showed that passing the gut by itself did not stimulate or limit germination. However, seeds that were released from the berries germinated about one month earlier compared to seeds contained in berries. This implies that being released from a fruit, for example through endozoochory, can have a large temporal germination and growth advantage, especially in northern ecosystems a with short growing season.
The use of detection dogs in conservation studies has expanded across species, conditions and habitats. However, it is incorrect to assume the potential associated with these surveys is automatically linked to the dog's sense of smell. Instead, an accurate detection dog rate is directly linked to many caveats in dog–handler training. Selecting a detection dog is directly linked to a clearly defined study design and must balance various factors, including: olfactory ability, physical structure, energy level, personality and social traits. Selection of training samples should ensure sufficient variation in target and nontarget species, independent of whether the goal is to locate evidence of the animal (e.g. scat, feather) or the physical animal. Just as not all dogs are appropriate, not all persons are suitable for this type of work, as the handler must be consistent and attentive to details with an incredible physical and mental endurance to sustain the time in the field. Testing in controlled and field situations can determine if the personalities of the dog and handler balance, with time needed for each to gain the ability to ‘read’ the other. Proper training for the dog and handler is essential, with special attention paid to the innate reactions of the latter. After training of the team is complete, testing trials should mimic field conditions. While there is no single model to becoming a handler in wildlife detection dog studies, incorporating these fundamental concepts with professional training can help optimize sample detection rate, minimize handler and dog frustration, and maximize overall success with this technique.
Christopher Beirne, Chase L. Nuñez, Melissa Baldino, Seokmin Kim, Julia Knorr, Taylor Minich, Lingrong Jin, Shuyun Xiao, Walter Mbamy, Guichard Ndzeng Obiang, Juliana Masseloux, Tanguy Nkoghe, Médard Obiang Ebanega, Colin Rundel, Justin P. Wright, John R. Poulsen
Seed gut passage times, the time from ingestion to defecation, and frugivore movement patterns determine patterns of seed deposition across the landscape and are thus crucial parameters to quantify in wild populations. Recent advancements in satellite and telemetry technologies mean that animal movement patterns are readily quantifiable in increasingly high resolution. However, data on wild frugivore gut passage times are scarce to non-existent due to the difficulty of monitoring seed ingestion and defecation in natural habitats; therefore, GPT estimates are often extrapolated from captive species whose diets and activity patterns may have limited transferability to free-ranging populations. Here we develop, trial and deploy a suite of model seeds to address this shortfall in wild African forest elephants Loxodonta cyclotis – one of the most effective seed dispersers in the tropics. We use a combination of ‘active’ seed mimics, which indirectly measure gut passage through recording temperature fluctuations, and ‘passive’ seed mimics, which serve to mark the point of defecation to allow gut passage estimation from time-stamped GPS collar data. In doing so, we present the first ever GPT estimates from wild forest elephants: mean = 39.8 h (min = 16.6 h; max = 113.7 h). The estimates were derived exclusively from passive seed mimics (plastic beads and modified native seeds) as all active seed mimics were rejected by the focal elephant. The methods described are translatable to other free-ranging, GPS-collared, species and if widely adopted, will begin to address the current gap in our understanding of seed dispersal by wild frugivores.
The aim of this study was to determine the seasonal activity patterns and asynchrony between different antler stages in male axis deer from the Mediterranean island of Rab in Croatia using camera traps. Nine cameras with an infrared motion detection system were used to track animal activity over a 12-month period, 24 h per day. Stags were divided into two categories of antler development: regeneration stage and hard antler stage. The frequency of detection of each category in the photographs allowed us to investigate seasonal activity patterns. To describe the seasonal activity pattern in each category, we fitted the segmented linear regression and predicted that the ratio of monthly activity of stags in the two antler categories would interchange regularly during the research period. Over the 12-month study period, 36 862 photographs were analysed. A significant difference in frequency was found between the two antler categories (p < 0.01), with a consistently greater presence of hard-antlered stags. The highest frequency of detection of both antler categories was found in the winter season, and the lowest in spring. The segmented linear regression clearly distinguished three break points in April, June and December in the hard antler stage, with a significant difference in activity pattern among the months for each slope. On the other hand, no significant difference was found for the regeneration stage. Therefore, the expected proportional interchange in the number of stags in the two antler stages throughout the year did not occur. This study revealed that the Mediterranean axis deer population showed a unique activity pattern, where antler stage may act as a possible driver regulating stag movements.
Eurasian lynx Lynx lynx L. are recolonizing parts of their former range in Europe. Not only are lynx strictly protected as a species, but also their habitat and in particular their resting sites are protected. As the known characteristics of lynx resting sites are restricted to vegetation structure, it is difficult to take resting sites into account in planning processes. Here, we show the importance of rock formations for potential resting sites selection and analyzed the frequencies at which GPS-collared lynx returned to potential resting sites in the Bohemian Forest Ecosystem at the border between the Czech Republic and Germany. Lynx showed a strong selection for proximity of rocks for resting site selection, and the distance of potential resting sites to rocks was an important predictor for determining whether lynx return to the resting site or not. Furthermore, the frequency of returns to the resting site was positively influenced by the distance to roads and geomorphology. Our findings highlight the importance of rock formations as resting sites for lynx, which can help with the implementation of concrete protection measures.
Many deforested areas worldwide have been planted with Alnus spp. to protect watersheds and soils. However, the effects of these plantations on biodiversity are little known yet. Contrasting forest types may impose strong environmental filters to some behavioural traits, leading to dissimilar communities. Insectivorous birds are known to be sensitive to changes in habitat structure due to their specialized foraging behaviour. We contrasted species richness, abundance and composition of insectivorous birds, according to functional behaviour groups (foraging strategy and stratum), between secondary forest stands and Andean alder Alnus acuminata plantations, to assess how contrasting forest types affect this bird group in the Colombian Andes. Insectivorous bird species richness and abundance were higher at the Alder plantation rather than at the secondary forest, resulting in dissimilar communities. In this regard, forest plantations act as a positive filter for foliage gleaners and flycatchers, whereas secondary forests act as a positive filter for bark foragers. Secondary forests and alder plantations impose different ecological scenarios to insectivorous birds, related to foraging strategies and foraging stratum, which ultimately leads to a dissimilar species composition.
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