D.P.J. Kuijper

• Dr hab.associate professor
• Mammal Research Institute, Polish Academy of Sciences

Effective conservation of biodiversity requires a good understanding of ecosystem dynamics in response to natural and anthropogenic influences. Long-term studies (LTS) conducted over multiple decades provide essential insights into ecological processes and interactions over time, which can inform conservation strategies, but they are anchored withi...

After a long period of persecution, wolves are recolonizing Europe's human-dominated landscapes. Previous studies from areas with low human presence or ongoing human risk find wolves to avoid humans. However, close human-wolf encounters are increasingly reported in areas where wolves are strictly protected and raise concerns about the potential hab...

Plants adopt particular growth‐forms when they are exposed to extreme environmental conditions. In this study, we describe a unique woody plant growth‐form induced by large mammalian herbivores and discuss that this growth‐form could have evolved as a strategy for escaping the browser zone in herbivore driven ecosystems. We analysed responses of ke...

Herbivorous insects alter biogeochemical cycling within forests, but the magnitude of these impacts, their global variation, and drivers of this variation remain poorly understood. To address this knowledge gap and help improve biogeochemical models, we established a global network of 74 plots within 40 mature, undisturbed broadleaved forests. We a...

[This corrects the article DOI: 10.1371/journal.pone.0279672.].

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...

The term “applied ecology of fear” was recently introduced to describe the growing research field that applies the theory of the ecology of fear to manage wildlife behaviour. The management goal is to drive targeted species spatially and temporally away from areas of human interest by inducing cues from real or simulated predators to reduce human‐w...

Predators can affect ecosystems through non‐consumptive effects (NCE) on their prey, which can lead to cascading effects on the vegetation. In mammalian communities, such cascading effects on whole ecosystems have mainly been demonstrated in protected areas, but the extent to which such effects may occur in more human‐dominated landscapes remains d...

The term pyric herbivory was first introduced in 2009, describing how fire shapes herbivory as burned areas attract herbivores and, simultaneously, herbivory shapes fuel load and fire behaviour. Pyric herbivory results in a mosaic of patches with varying levels of herbivory and grazing intensity fire intensity and frequency. The importance of pyric...

Over the last decades, wolves have considerably expanded their distribution in Europe. Their range expansion even led to recolonizing densely human‐populated countries such as Belgium and the Netherlands. The few available studies on the effects of returning wolves in these landscapes focus primarily on the behavioral responses of wild ungulates, s...

The wolf (Canis lupus) is arguably the most successful species at recolonizing its now human‐dominated former ranges in Europe and North America. Over the centuries while the wolf was absent, humans have transformed ecosystems to a large extent. In this paper, we highlight key aspects of these human‐modified ecosystems that include changes to (meso...

Understanding the relationship between a species feeding strategy and its environment (trophic ecology) is critical to assess environmental requirements and improve management policies. However, measuring trophic interactions remains challenging. Among the available methods, quantifying the plant composition of a species’ diet indicates how species...

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...

Relationships among carnivore species are complex, potentially switching from competition to facilitation on a context-dependent basis. Negative associations are predicted to increase with latitude, due to limited resources emphasising competition and/or intra-guild predation. Accordingly, a stronger negative correlation between large- and meso-car...

Camera trapping has revolutionized wildlife ecology and conservation by providing automated data acquisition, leading to the accumulation of massive amounts of camera trap data worldwide. Although management and processing of camera trap‐derived Big Data are becoming increasingly solvable with the help of scalable cyber‐infrastructures, harmonizati...

Terrestrial ecosystems are shaped by interacting top‐down and bottom‐up processes, with the magnitude of top‐down control by large carnivores largely depending on environmental productivity. While carnivore‐induced numerical effects on ungulate prey populations have been demonstrated in large, relatively undisturbed ecosystems, whether large carniv...

Predators can affect ecosystems through non-consumptive effects on their prey, which can lead to cascading effects on the vegetation. In mammalian communities, such cascading effects on whole ecosystems have mainly been demonstrated in protected areas, but the extent to which such effects may occur in more human-dominated landscapes remains disputa...

Camera trapping has revolutionized wildlife ecology and conservation by providing automated data acquisition, leading to the accumulation of massive amounts of camera trap data worldwide. Although management and processing of camera trap-derived Big Data are becoming increasingly solvable with the help of scalable cyber-infrastructures, harmonizati...

The European grey wolf (Canis lupus) and the domestic dog (Canis lupus familiaris) share not only a common origin but also many similarities in their behavior. Due to the implementation of protection wolves repopulated large parts of Europe. The increase of wolves in human-dominated landscapes also leads to a growing potential for interactions betw...

The gray wolf Canis lupus was extirpated from western Poland, but since enforcement of strict protection in 1998 recolonized most of the suitable habitats. One of such recently recolonized areas is Tuchola Forest, a large forest complex in northwestern Poland, where an alien medium-sized ungulate species, fallow deer Dama dama, was introduced for h...

The European grey wolf (Canis lupus) and the domestic dog (Canis lupus familiaris) share not only a common origin, but also many similarities in their behavior. Because of their improved protection, wolf populations have increased in Poland and across Europe. The increasing presence of wolves in human-dominated landscapes brings them increasingly i...

Aim Several large‐mammal species in Europe have recovered and recolonized parts of their historical ranges. Knowing where suitable habitat exists, and thus where range expansions are possible, is important for proactively promoting coexistence between people and large mammals in shared landscapes. We aimed to assess the opportunities and limitation...

Understanding the relationship between a species feeding strategy and its environment (trophic ecology) is critical to assess environmental requirements and improve management policies. However, measuring trophic interactions remains challenging. Among the available methods, quantifying the plant composition of a species' diet indicates how species...

Large carnivores not only supress mesocarnivores via killing and instilling fear, but also facilitate them through carrion provisioning. Hence, mesocarnivores frequently face a trade-off between risk avoidance and food acquisition. Here we used the raccoon dog and red fox in Białowieża Forest, Poland as models for investigating how large carnivores...

Altered interactions between pathogens, their hosts and vectors have potential consequences for human disease risk. Notably, tick-borne pathogens, many of which are associated with growing deer abundance, show global increasing prevalence and pose increasing challenges for disease prevention. Human activities can largely affect the patterns of deer...

Tree architectures reflect the main abiotic and biotic selection pressures determining tree growth and survival. Studies have shown that trees growing in herbivore‐dominated ecosystems, such as savannas, develop denser, more divaricate ‘cage’‐like architectures in response to chronic browsing pressure (also known as ‘brown world’ architectures). In...

Wild ungulates are a major consumer of agricultural crops in human dominated landscapes. Across Europe, ungulate populations are leading to intensified human-wildlife conflicts. At the same time, ungulates play a vital role in the structuring and functioning of ecosystems, and are highly appreciated for recreational hunting. Thus, managers often fa...

There are several mechanisms that allow plants to temporarily escape from top-down control. One of them is trophic cascades triggered by top predators or pathogens. Another is satiation of consumers by mast seeding. These two mechanisms have traditionally been studied in separation. However , their combined action may have a greater effect on plant...

The recolonization of human-dominated landscapes by large carnivores has been followed with considerable scientific interest; however, little is known about their interactive effect on ungulate foraging behavior. This study compared the risks imposed by humans and lynx on ungulate foraging behavior by examining the effects of browsing intensity (at...

Humans are increasingly acknowledged as apex predators that shape landscapes of fear to which herbivores adapt their behaviour. Here, we investigate how humans modify deer space‐use and their effects on vegetation at two spatial scales; zones with different types of human use (largescale risk factor) and, nested within that, trails (fine‐scale risk...

Fire and herbivory are fundamental top‐down processes, structuring grass–tree ratios in ecosystems across a diversity of climates. Both are plant consumers that can strongly control the recruitment of woody seedlings and saplings to taller height classes. Without consumer control, many grass‐dominated ecosystems would convert into woodlands or fore...

Camera traps are used worldwide to monitor wildlife. Despite the increasing availability of Deep Learning (DL) models, the effective usage of this technology to support wildlife monitoring is limited. This is mainly due to the complexity of DL technology and high computing requirements. This paper presents the implementation of the light-weight and...

This study examined the effect of perceived predation risk imposed by lynx (Lynx lynx) and wolf (Canis lupus) on red deer (Cervus elaphus) foraging behavior under experimental conditions. We hypothesized that in response to large carnivore scent red deer would increase their vigilance, although reducing the frequency and duration of visits to forag...

Camera traps are used worldwide to monitor wildlife. Despite the increasing availability of Deep Learning (DL) models, the effective usage of this technology to support wildlife monitoring is limited. This is mainly due to the complexity of DL technology and high computing requirements. This paper presents the implementation of the light-weight and...

Impediments, such as tree logs, can prevent access to saplings for deer, and can increase perceived predation risk by blocking view and escape possibilities for deer in areas with large carnivores. Therefore, impediments can influence deer foraging decisions and the trade-off between safety and food of different quality indirectly influencing tree...

Context Ungulate prey can use increased vigilance to reduce their risk of predation, but little is known of the combined and interactive risk effects from humans and wolves in determining ungulate behaviour across time and space. Understanding the interplay between these risk effects is increasingly important, considering the recolonisation of seve...

We analyzed the effect of forest management and wolf (Canis lupus) space-use on diet composition of red deer (Cervus elaphus) and European bison (Bison bonasus) in Białowieża Primeval Forest (BPF), Poland. The red deer is the main prey species for the wolf, whereas the European bison is rarely preyed upon. As both species behave as intermediate fee...

Many 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 predat...

African swine fever (ASF) has been spreading in the Eurasian continent for more than 10 years now. Although the course of ASF in domestic pigs and its negative economic impact on the pork industry are well-known, we still lack a quantitative assessment of the impact of ASF on wild boar (Sus scrofa) populations under natural conditions. Wild boar is...

In Europe brown bears are currently largely confined to mountainous areas and eastern European refugia with sparse human populations. Poland typifies this distribution, with bears being present in the Carpathian Mountains, but absent from the lowlands. Recently large carnivore populations have been recovering throughout Europe, raising the question...

Large carnivores are recolonizing many regions in Europe, where their ungulate prey have lived without them for >150 years. Whether the returning large carnivores will modify ungulate behavior and indirectly affect lower trophic levels, depends on the ability of ungulates to recognize risk based on past encounters and cues indicating carnivore pres...

Large herbivores influence ecosystem functioning via their effects on vegetation at different spatial scales. It is often overlooked that the spatial distribution of large herbivores result from their responses to interacting top-down and bottom-up ecological gradients that create landscape-scale variation in the structure of the entire community....

The long‐term influence of persistent small herbivores on successional plant community configuration is rarely studied. We used a herbivore exclusion experiment along the successional gradient in a salt‐marsh system, to investigate the effects of hares and geese, and hares alone, on plant diversity at five successional stages (the earliest, two ear...

Landscapes of fear have become widely studied in the northern hemisphere, but are still largely understudied in the more complex, diverse carnivore-prey communities of Africa. Habitat changes brought about by a mega-herbivore, the African elephant (Loxodonta africana), can modify the perceived landscape of fear by predation vulnerable prey species...

The recolonization of wolves in European human-dominated landscapes poses a conservation challenge to protect this species and manage conflicts. The question of how humans can co-exist with large carnivores often triggers strong emotions. Here we provide an objective, science-based discussion on possible management approaches. Using existing knowle...

Article impact statement: Participation is not a panacea for the Białowieża conflict; scientific evidence exists and can inform valid policy options.

Pellet counts are widely used to monitor ungulates but rely on the assumption that pellets of different species are correctly identified in the field. Recent studies question this assumption using DNA barcoding techniques to check field identification rates. For Europe, which is undergoing a rapid shift towards more diverse ungulate assemblages, su...

Spatial variation in habitat riskiness has a major influence on the predator–prey space race. However, the outcome of this race can be modulated if prey shares enemies with fellow prey (i.e., another prey species). Sharing of natural enemies may result in apparent competition, and its implications for prey space use remain poorly studied. Our objec...

Large carnivores can reduce ungulate numbers by predation and via induced risk effects alter ungulate behavior, indirectly affecting lower trophic levels. However, predator-induced risk effects probably act at different spatial scales, which have often been ignored in trophic cascade studies. We studied how a fine-scale risk factor (distance from t...

Loggings in biodiversity hot-spots are perceived as very serious threat to forest species and habitats of high conservation interest. In this paper we scrutinize the spatial impacts of recent loggings in the Polish part of the renowned Białowieża Forest being the last remaining area of lowland temperate forest with a primeval character in Europe wi...

Ecology and conservation biology have recently become increasingly data intensive, mainly due to technological advances and the growing inter-disciplinary character. However, a data-intensive science needs specific information infrastructure and tools to efficiently manage, integrate, share and (re)use massive amounts of data. An open source softwa...

Question Functional plant traits often express consistent changes along ecological gradients and, hence, are often used as indicators of environmental change (e.g. nutrient availability, temperature changes). Besides being driven by edaphic conditions, functional plant composition is filtered by herbivory, and traits responsive to nutrient availabi...

Understanding how the relationships between large carnivores and humans have evolved and have been managed through centuries can provide relevant insights for wildlife conservation. The management history of many large carnivores has followed a similar pattern, from game reserved for nobility, to persecuted pests, to conservation targets. We recons...

Large carnivores can be a key factor in shaping their ungulate prey's behavior, which may affect lower trophic levels. While most studies on trade-offs between food acquisition and risk avoidance by ungulate prey species have been conducted in areas with limited human impact, carnivores are now increasingly returning to highly anthropogenic landsca...

Predation is a major selective pressure for prey; however, the stress response to predation risk and the relative importance of natural versus anthropogenic stress factors in wild populations of animals have rarely been studied. We investigated the level of fecal glucocorticoid metabolites (FGMs) in 6 populations of red deer and roe deer exposed to...

Plant biomass consumers (mammalian herbivory and fire) are increasingly seen as major drivers of ecosystem structure and function but the prevailing paradigm in temperate forest ecology is still that their dynamics are mainly bottom‐up resource‐controlled. Using conceptual advances from savanna ecology, particularly the demographic bottleneck model...

Large carnivores are frequently presented as saviours of biodiversity and ecosystem functioning through their creation of trophic cascades, an idea largely based on studies coming primarily out of relatively natural landscapes. However, in large parts of the world, particularly in Europe, large carnivores live in and are returning to strongly human...

Dorresteijn et al . [[1][1]] recently addressed the question what influence humans have on predator–prey interactions in human-modified landscapes. Their study follows increasing evidence from relatively natural landscapes that large carnivores are central drivers of ecosystem structure and

Pasturing of livestock in forests has had profound consequences for Europe's landscapes. In Białowieża Primeval Forest (BPF), cattle pasturing was a part of traditional forest use that ceased only in the second half of the twentieth century. We collected information on the institutional changes governing forest cattle pasturing and the changes in s...

The reduction of human use in many grassland systems across Europe has led to bush encroachment and a loss of biodiversity. Low intensity grazing systems by livestock has often been used as a cost-effective management tool to counteract this process. However, not all semi-natural grasslands are suitable for this due to large distance from human set...

Camera trapping is increasingly becoming an important tool in ecological research. However, the organization of large collections of multimedia files and especially efficient searching for subsets of data is a challenging task. While the development of project‐specific software solutions is dominating in the camera trapping community, little attent...

There is a growing evidence that members of animal groups synchronize their vigilance behavior to minimize predation risk. Because synchronized vigilance deviates from the classical vigilance models, which assume independent scanning, it is important to understand when and why it occurs. We explored vigilance behavior of wild boar (Sus scrofa) in a...

Climate changes also affect European forests. Some species of trees, like Norway spruce Picea abies, are sensitive to high temperatures and water deficiency. After having been weakened by summer droughts they become vulnerable to more intensive colonization of tree-eating insects. Spruce trees which become infested by the European spruce bark beetl...

The widespread decline of the European brown hare (Lepus europaeus) in Europe has been attributed to both bottom-up and top-down factors, as well as climate change. Few studies have attempted to study the relative importance of these factors considered simultaneously. In this study we tested the hypotheses that hare population density is regulated...

Large mammalian carnivores create areas perceived as having high and low risk by their ungulate prey. Human activities can indirectly shape this landscape of fear by altering behavior and spatial distribution of carnivores. We studied how red deer perceive the landscape of fear in an old-growth forest system (Białowieża Primeval Forest, Poland) bot...

A crucial element in the “the landscape of fear” concept is that prey animals are aware of varying levels of predation risk at a spatial scale. This often leads to a negative spatial relationship between prey and predator in which prey avoid the most risky sites in the landscape. In this paper we argue that our understanding of large carnivore-ungu...

Ambush predators provide more persistent cues of predation risk compared to coursing predators and are predicted to exert stronger effects on behaviour of their prey. We studied anti-predator responses of ungulates by means of camera traps to an olfactory cue (fresh scat) of an ambush predator, the Eurasian lynx (Lynx lynx). Roe deer (Capreolus cap...

As researchers try to predict the effects of human modification at all trophic levels and mediate the impact of rapid environmental change, it has become clear it is no longer a matter of agreeing that both bottom-up and top-down forces play important roles in diverse ecosystems. Rather, the question is: how do these forces interact across aquatic...

As researchers try to predict the effects of human modification at all trophic levels and mediate the impact of rapid environmental change, it has become clear it is no longer a matter of agreeing that both bottom-up and top-down forces play important roles in diverse ecosystems. Rather, the question is: how do these forces interact across aquatic...

Body size of vertebrate herbivores is strongly linked to other life history traits, most notably (1) tolerance of low quality forage and (2) vulnerability to predation, which both impact the composition and dynamics of natural communities. However, no study has thus far explored how the combination of these two body-size related traits affect the l...

Body size of vertebrate herbivores is strongly linked to other life history traits, most notably (1) tolerance of low quality forage and (2) vulnerability to predation, which both impact the composition and dynamics of natural communities. However, no study has thus far explored how the combination of these two body-size related traits affect th...

Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in the Białowieża Primeval Forest (Poland), whether pe...

Large carnivores can either directly infuence ungulate populations or indirectly afect their behaviour. Knowledge from European systems, in contrast to North American systems, on how this might lead to cascading efects on lower trophic levels is virtually absent. We studied whether wolves Canis lupus via density-mediated and behaviorally-mediated e...

In forested ecosystems, oak saplings can be found in association with coarse woody debris (CWD) that offers protection against herbivore browsing. In this study we investigated whether CWD is already a safe site during the earlier stages of oak recruitment, i.e. at the seed and seedling phase, or whether these phases require different micro-environ...

1. There is a growing theoretical basis for the role of predation risk as a driver of trophic interactions, conceptualized as the ‘ecology of fear’. However, current ungulate management ignores the role of nonlethal risk effects of predation. 2. We introduce the concept of ‘hunting for fear’ as an extension of the more classical ‘hunting to kill’ t...

While oaks contribute to the ecology and economy of temperate lowland forests, recruitment into larger size classes is generally scarce. Ungulate herbivory is a limiting factor for tree recruitment, thus natural structures protecting against ungulates may be important for recruitment success. We studied oak recruitment in relation to coarse woody d...

Small vertebrate herbivores retard vegetation succession in young stages of barrier-island salt-marsh succession. They cannot do so at later successional stages due to increasing soil productivity by the sedimentation of nitrogen containing clay. At later, productive stages of succession, grazing by livestock can reduce the dominance of late succes...

Across Europe, ungulate numbers have greatly increased over the past decades, leading to increasing concerns about the ecological and economical impacts and pleas for stronger population control. However, focussing on population control only ignores other underlying factors which may enhance the wildlife–forestry conflict. I reviewed factors which...

On minerogenic barrier-island salt marshes, sedimentation is spatially heterogeneous. Although the main forcing factors for sedimentation are known, much less is known about the characteristic sizes of this spatial patterning. Such patterning gives information on the spatial component of salt-marsh formation and on the uncertainty in measured accre...

Browsing lawns, as an analogue of the influential grazing lawn concept, received increased recent interest. We revisit this concept and ask whether the underlying characteristics of a grazing lawn can indeed be generalized to browser–woody plant interactions. Based on previous studies, we define a lawn as a grazed or browsed patch in which intense...

Wooded pastures grazed by livestock are believed to be landscapes that provide favourable conditions for spontaneous regeneration of oaks, including Quercus robur. A key mechanism for oak regeneration in these systems is ‘associational resistance’, spatial association with unpalatable plants which offer protection against herbivory. There is little...

Studies in the Canadian Arctic show dramatic effects of increased goose grazing on vegetation structure and soil conditions, but little is known of the role of goose grazing in the European Arctic. We focused on how geese might affect plant recruitment via effects on seed production and soil seed bank in High Arctic Svalbard. Experimental grazing b...

Question: What are the main driving factors in 70 years of natural dynamics in tree recruitment in the Białowieża National Park?Location: Białowieża National Park, Poland, is one of the least disturbed temperate, lowland forest systems in Europe.Methods: We tested whether fluctuations in large herbivore populations, changes in climate and openness...