Josip Kusak

University of Zagreb · Department of Biology

Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group‐level processes such as subgroup formation and fission–fusion dynamics. Although critical t...

The estimation of foraging parameters is fundamental for understanding predator ecology. Predation and feeding can vary with multiple factors, such as prey availability, presence of kleptoparasites and human disturbance. However, our knowledge is mostly limited to local scales, which prevents studying effects of environmental factors across larger...

Gray wolves Canis lupus comprise one of the most widely distributed carnivore species on the planet, but they face myriad environmental and anthropogenic pressures. Previous research suggests that wolves adjust their time‐ and space‐use seasonally to mitigate risks from humans, conspecifics, and other predators while maximizing their hunting and re...

Wildlife in the Anthropocene is increasingly spatially and temporally constrained by lethal and non-lethal human disturbance. For large carnivores with extensive space requirements, like wolves and Eurasian lynx, avoiding human disturbance in European landscapes is challenging when sufficient space with low disturbance is rarely available. Conseque...

Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amo...

Rehabilitation of injured or immature individuals has become an increasingly used conservation and management tool. However, scientific evaluation of rehabilitations is rare, raising concern about post-release welfare as well as the cost-effectiveness of spending scarce financial resources. Over the past 20 years, events of juvenile Eurasian lynx p...

Aim: The increasing availability of animal tracking datasets collected across many sites provides new opportunities to move beyond local assessments to enable detailed and consistent habitat mapping at biogeographical scales. However, integrating wildlife datasets across large areas and study sites is challenging, as species' varying responses to d...

Large carnivores are known for altering their life-history strategies in response to environmental change. One such shift was recently discovered in Eurasian brown bears ( Ursus arctos arctos ) in Sarıkamış, Eastern Türkiye where an open city garbage dump has led to the emergence of two distinct life strategists: sedentary bears that use the city d...

Human-wildlife conflict is increasing steadily worldwide and is rapidly becoming an important challenge for the success of conservation programs. Brown bears, which suffer from reduced habitat suitability and quality globally, frequently conflict with humans. These animals need large home ranges to fulfill their habitat requirements. When space and...

Integrating data across studies with traditional microsatellite genetic markers requires careful calibration and represents an obstacle for investigation of wide-ranging species where populations require transboundary management. We used the “yardstick” method to compare results published across Europe since 2002 and new wolf (Canis lupus) genetic...

COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no c...

Terrestrial top carnivores are susceptible to renal and hepatic accumulation of persistent inorganic pollutants due to their trophic position. Toxic potential of metal(loid)s taken up by prey consumption carries the risk of adverse effects for exposed predator. Eurasian lynx (Lynx lynx) and European wildcat (Felis silvestris silvestris) are strictl...

Context Adjustments in habitat use by large carnivores can be a key factor facilitating their coexistence with people in shared landscapes. Landscape composition might be a key factor determining how large carnivores can adapt to occurring alongside humans, yet broad-scale analyses investigating adjustments of habitat use across large gradients of...

Mountain regions have long been important for maintaining populations and genetic diversity of wild species, especially those species that require large areas to sustain viable populations. We examined wolves (Canis lupus) in the Caucasus, Carpathian, and Dinaric–Balkan regions, expecting these persistent populations to contain high genetic diversi...

Trace element pollution can adversely affect the brains of individuals and thus impact the entire population of apex predators, such as large European carnivores. We assessed exposure to prominent neurotoxicants As, Cd, Hg and Pb by measuring their brain stem levels in brown bears (n = 114), grey wolves (n = 8), Eurasian lynx (n = 3), and golden ja...

Hematology is one of the best population health indicators, and the quickest way to gain insight into some hematological parameters is blood film evaluation. Sometimes, due to the inability to store blood, the unavailability of hematological instruments during field work, or the insufficient amount of blood for complete hematological analysis, bloo...

ContextBehavioral adjustments by large carnivores can be a key factor facilitating their coexistence with people in shared landscapes. Landscape composition might be a key factor determining how large carnivores can adapt to occurring alongside humans, yet broad-scale analyses investigating adjustments of habitat use across large gradients of human...

Intra- and inter-specific gene flow are natural evolutionary processes. However, human-induced hybridization is a global conservation concern across taxa, and the development of discriminant genetic markers to differentiate among gene flow processes is essential. Wolves (Canis lupus) are affected by hybridization, particularly in southern Europe, w...

The present phylogeographic pattern of red deer in Eurasia is not only a result of the contraction of their distribution range into glacial refugia and postglacial expansion, but probably also an effect of replacement of some red deer s.l. mtDNA lineages by others during the last 50 000 years. To better recognize this process, we analysed 501 seque...

Scientific data on distribution and abundance of endangered species are the foundation for their effective conservation and management. In this paper, we present results of the first scientifically – based estimation of lynx population size in Croatia. The goal of the study was to determine the area of lynx distribution and to estimate the minimum...

The Balkan Peninsula and the Dinaric Mountains possess extraordinary biodiversity and support one of the largest and most diverse wolf (Canis lupus) populations in Europe. Results obtained with diverse genetic markers show west-east substructure, also seen in various other species, despite the absence of obvious barriers to movement. However, the s...

Predator-prey interactions and human presence are among the key factors shaping large mammal activity patterns. In human-dominated landscapes, large carnivores must balance their activity rhythms between optimizing their feeding opportunities and avoiding encounters with humans. In north-eastern Turkey, the Caucasian lynx (Lynx lynx dinniki), a thr...

Horvatov brijeg, zemljani brežuljak smješten na sjeverozapadnom dijelu perivoja Veterinarskog fakulteta u Zagrebu nazvan je prema svom idejnom tvorcu, znamenitom hrvatskom znanstveniku, botaničaru i profesoru, Ivi Horvatu. Veterinarski fakultet zakonom je zaštićeni povijesni paviljonski kompleks, odnosno dio Povijesne urbane cjeline Grada Zagreba s...

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundr...

Turkey is the only country in the world that is almost entirely covered by three global biodiversity hotspots (Caucasus, Iran-Anatolian and Mediterranean), and yet its biodiversity and ecosystems are greatly threatened. Nevertheless in the northeast, where the human population is declining, there is still some potential for the conservation of larg...

Studying how animals interact with their environment is fundamental to informing conservation and management efforts, especially when examining large, wide-ranging carnivores in human-dominated landscapes. We hypothesized that the home ranges of bears are configured to exploit supplemental food (corn) and avoid people. In 2004–2016, we tracked 10 b...

The feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) may cause persistent, lifelong and lethal infections in domestic and wild felids worldwide. FIV has been confirmed in most Felidae species, while FeLV infection is rare among non-domestic cats. The view that retroviruses are pathogenic in domestic cats but not in other free-ra...

Seasonal migrations (i.e. seasonal round‐trips between disjunct areas) have been rarely documented for large carnivores. The Dinaric‐Pindos brown bear (Ursus arctos) population is the third largest in Europe, but little information is currently available on individual movement patterns. We studied movement patterns by 12 GPS‐collared adult and suba...

Bears have fascinated people since ancient times. The relationship between bears and humans dates back thousands of years, during which time we have also competed with bears for shelter and food. In modern times, bears have come under pressure through encroachment on their habitats, climate change, and illegal trade in their body parts, including t...

Bosnia and Herzegovina (B&H) is considered as a core area for Dinaric-Pindos/Dinaric-Balkan large carnivore populations. Unfortunately, little is known about their population parameters as well as feeding ecology which represents a serious threat to the management of those populations. This particularly applies to wolves (Canis lupus), which are co...

Tensions between humans and wolves have led to intensive worldwide studies of wolf feeding habits and their relative preference for domestic and wild ungulates. The aim of this study was to provide further insight into the diet composition of wolves in Croatia, based on stomach contents of dead wolves. We examined spatial variation in wolf diet and...

While constrained by endogenous rhythms, morphology and ecology, animals may still exhibit flexible activity patterns in response to risk. Temporal avoidance of interspecific aggression can enable access to resources without spatial exclusion. Apex predators, including humans, can affect mesopredator activity patterns. Human context might also modi...

The raccoon dog (Nyctereutes procyonoides) was recorded for the first time in Turkey on May 10, 2019, and June 5, 2019, in the same location after 4668 nights of camera trapping in the forests of the Sarıkamış region and Allahuekber Mountains in eastern Turkey. It was recorded in a Scots pine (Pinus sylvestris) forest at 2340 m above sea level with...

The purpose of this guidebook is to provide detailed information for field investigations to identify the cause of death of livestock when attacks by carnivores are suspected. It will assist damage inspectors, agricultural advisers, and others in determining the species of wildlife that cause damage. Additionally, this guide will help users recogni...

Anthropogenic hybridization is widely perceived as a threat to the conservation of biodiversity. Nevertheless, to date, relevant policy and management interventions are unresolved and highly convoluted. While this is due to the inherent complexity of the issue, we hereby hypothesize that a lack of agreement concerning management goals and approache...

Since the biggest threat to large carnivore survival is habitat fragmentation and loss, the best approach for reduction and avoidance of individual and cumulative impacts is appropriate spatial positioning of windfarms and individual wind turbines. Therefore the Manual propose an assessment methodology based on the sensitivity map (Fig 1), which wa...

Pan-European legislation stimulates international cooperation to overarching challenges of large carnivore management across jurisdictions. We present an analysis for current transboundary brown bear (Ursus arctos) population management in Croatia and Slovenia. Slovenia's bear management attempts aimed to reduce human-bear conflicts, by limiting th...

Habitat loss and fragmentation can severely hamper species ability to undertake long-distance movements (e.g. dispersal, migration), impeding both gene ow and access to critical habitat. In some European brown bear populations, the need for increasing pre-wintering food intake can lead to individual migration-like movement patterns, with animals co...

Where direct killing is rare and niche overlap low, sympatric carnivores may appear to coexist without conflict. Interference interactions, harassment and injury from larger carnivores may still pose a risk to smaller mesopredators. Foraging theory suggests that animals should adjust their behaviour accordingly to optimise foraging efficiency and o...

This article presents the first case of intestinal adenocarcinoma in a free living, culled 12 year old, European female brown bear (Ursus arctos), with its characteristic macropathological and histopathological manifestations. Necropsy revealed thoracic gunshot injuries (compassionate shot) and the poor physical condition of the animal, with body f...

Wolf-dog hybridization is considered as one of the main threats for wolf conservation since the admixture and introgression of domestic genes may disrupt local adaptations and threaten the long term survival of wild wolf populations. We investigated the occurrence of wolf-dog hybridization in Croatia by analyzing a panel of 12 autosomal microsatell...

Reproductive control is regularly implemented in bear facilities to prevent crowding of enclosures and surplus animals. Ovariectomy may represent an efficient method of sterilizing bears yet has not been reported in the literature. A 73 kg female brown bear, age two years and three months, was anesthetized for ovariectomy with tiletamin and zolazep...

Tissue element investigations of apex terrestrial mammals are very scarce in Europe. We quantified 16 essential and non-essential elements in the kidney cortex, liver and muscle tissue of 467 brown bears (Ursus arctos), 125 grey wolves (Canis lupus), one Eurasian lynx (Lynx lynx) and three golden jackals (Canis aureus) from Croatia by inductively c...

Context. The preservation of denning habitat is paramount to the recovery of threatened bear populations because of the effect that den site disturbance can have on cub mortality. Understanding habitat suitability for denning can allow management efforts to be directed towards the regions where conservation interventions would be most effective. Ai...

Background Babesia spp. and Theileria spp. are important emerging causes of disease in dogs. Alongside these domesticated hosts, there is increasing recognition that these piroplasms can also be found in a range of wild animals with isolated reports describing the presence of these pathogen in foxes (Vulpes vulpes) and captive grey wolves (Canis lu...

OPEN ACCESS FULL TEXT AT: http://rdcu.be/qaQl ---------- In order to meet carbon reduction targets, many nations are greatly expanding their wind power capacity. However, wind farm infrastructure potentially harms wildlife, and we must therefore find ways to balance clean energy demands with the need to protect wildlife. Wide-ranging carnivores liv...

The ongoing refugee crisis in Europe has seen many countries rush to construct border security fencing to divert or control the flow of people. This follows a trend of border fence construction across Eurasia during the post-9/11 era. This development has gone largely unnoticed by conservation biologists during an era in which, ironically, transbou...

Plastic behavioral adaptation to human activities can result in the enhancement andestablishment of distinct behavioral types within a population. Such inter-individualbehavioral variations, if unaccounted for, can lead to biases in our understandingof species’feeding habits, movement pattern and habitat selection. We tracked themovements of 16 adu...

We investigated wolf feeding ecology in Kars province, north-eastern Turkey, by analyzing 72 scat samples collected in spring 2013. Ongoing camera trap surveys suggest that large wild ungulates are exceptionally rare in the region. On the contrary, livestock is abundant. Accordingly, scats analysis revealed that livestock constituted most of the bi...

The combination of intensive persecution, habitat loss and prey deficiency led to the extinction of Eurasian lynx (Lynx lynx) in the Dinaric Mountains at the beginning of the 20th century. In 1973, the population was re-established by reintroducing animals from the Slovakian Carpathian Mountains into Slovenia, from where the animals spread into Cro...