Risky Sites Research Articles

Predation risk regulates prey assortative mating by reducing the expected reproductive value of mates.

Many animals exhibit size assortative mating (SAM), but how predation affects it remains largely unknown. We hypothesized that predation risk may turn prey less choosy, disrupting SAM, or reduce the expected reproductive value of mates, maintaining SAM but with different size ratio between mates. Using a manipulative field experiment, we found that desert isopods under risk of scorpion predation maintained SAM, but that males that choose and fight over females were on average smaller for a given female size. Less pairs were formed in risky sites, but there were no differences in female sizes and progeny number, size and age near and away from scorpion burrows. Our complementary behavioral experiments revealed that bigger males stayed longer near safe burrows, and won more male-male contests than smaller conspecifics. Our findings highlight that prey can anticipate future costs of predation and use this information to assess the expected reproductive value of mates.

CNN-LSTM-ATTENTION DEEP LEARNING MODEL FOR MAPPING LANDSLIDE SUSCEPTIBILITY IN KERALA, INDIA

Abstract. As a typical type of natural disaster, landslides may result in injuries to humans, threats to property security, and economic loss. As such, it is important to understand or predict the probability of landslide occurrence at potentially risky sites. Using typically machine learning (ML) to estimate landslide susceptibility based on a landslide inventory and a set of factors that impact the occurrence of landslides is a common practice. However, in landslide susceptibility assessment, existing DL-based neural network methods use a fully connected layer to optimize the selection of factors, which limits their efficiency in extracting features of those contributing factors. In response to those problems, this study proposed a CNN-LSTM model with an attention mechanism (AM) to avoid the complex optimization of input factors while the same or even better prediction accuracy can be achieved. To compare our method with the existing ones, the historical landslide inventory and the remote sensing data of Kerala, India were used to produce the input variables needed in the methods considered. The results show that our method produced more accurate results, compared to those existing neural network methods (e.g. CNN, LSTM and CNN-LSTM).

CLINICAL AND PATHOLOGIC CRITERIA TO DIAGNOSE PROLIFERATIVE VERRUCOUS LEUKOPLAKIA: AN UPDATE REVIEW AND A CASE REPORT

Objectives The objectives of this study were to describe clinical and pathologic features of the proliferative verrucous leukoplakia (PVL), including differential diagnosis and current criteria to diagnose PVL, and to report a case of PVL. Study Design Electronic research was carried out for the previous 5 years in the PubMed, BVS, and Scielo databases using “proliferative verrucous leukoplakia” as search the term. Results A total of 76 papers were found through databases, and 34 of them were eligible. We identified 3 studies that proposed new diagnosis clinical and histologic criteria. The lesion size and architectural histologic features are important factors to diagnose PVL. Not all PVLs exhibit a verrucous appearance. The most common differential diagnoses reported were lichenoid and reactive lesions. The risky sites to develop PVL and cancer are gingiva, especially that forming a “ring around the collar” in marginal gingiva, followed by buccal mucosa, tongue, and palate in female patients. Our case initially involved the tongue of a 79-year-old female patient with malignant transformation after 13 years of follow-up. Conclusions Even though the findings are helpful, there is no standardized criteria to diagnose PVL. Therefore, close clinical follow-up with periodic biopsies is the best approach to diagnose PVL and its progression to carcinoma. The objectives of this study were to describe clinical and pathologic features of the proliferative verrucous leukoplakia (PVL), including differential diagnosis and current criteria to diagnose PVL, and to report a case of PVL. Electronic research was carried out for the previous 5 years in the PubMed, BVS, and Scielo databases using “proliferative verrucous leukoplakia” as search the term. A total of 76 papers were found through databases, and 34 of them were eligible. We identified 3 studies that proposed new diagnosis clinical and histologic criteria. The lesion size and architectural histologic features are important factors to diagnose PVL. Not all PVLs exhibit a verrucous appearance. The most common differential diagnoses reported were lichenoid and reactive lesions. The risky sites to develop PVL and cancer are gingiva, especially that forming a “ring around the collar” in marginal gingiva, followed by buccal mucosa, tongue, and palate in female patients. Our case initially involved the tongue of a 79-year-old female patient with malignant transformation after 13 years of follow-up. Even though the findings are helpful, there is no standardized criteria to diagnose PVL. Therefore, close clinical follow-up with periodic biopsies is the best approach to diagnose PVL and its progression to carcinoma.

UAV-Based Landfill Land Cover Mapping: Optimizing Data Acquisition and Open-Source Processing Protocols

Earth observation technologies offer non-intrusive solutions for monitoring complex and risky sites, such as landfills. In particular, unmanned aerial vehicles (UAVs) offer the ability to acquire data at very high spatial resolution, with full control of the temporality required for the desired application. The versatility of UAVs, both in terms of flight characteristics and on-board sensors, makes it possible to generate relevant geodata for a wide range of landfill monitoring activities. This study aims to propose a robust tool and to provide data acquisition guidelines for the land cover mapping of complex sites using UAV multispectral imagery. For this purpose, the transferability of a state-of-the-art object-based image analysis open-source processing chain was assessed and its sensitivity to the segmentation approach, textural and contextual information, spectral and spatial resolution was tested over the landfill site of Hallembaye (Wallonia, Belgium). This study proposes a consistent open-source processing chain for the land cover mapping using UAV data with accuracies of at least 85%. It shows that low-cost red-green-blue standard sensors are sufficient to reach such accuracies and that spatial resolution of up to 10 cm can be adopted with limited impact on the performance of the processing chain. This study also results in the creation of a new operational service for the monitoring of the active landfill sites of Wallonia.

Revealing XRF data quality level, comparability with ICP-ES/ICP-MS soil PTE contents and similarities in PTE induced health risk.

Portable X-ray fluorescence spectroscopy (XRF) was recognized as an efficient and promising tools to study the contents of chemical elements in various media including soils under the impact of anthropogenic activities. However, the quality of data and the equality of chemical elements with other common analytical methods such as aqua-regia extraction vary depending on site, sample conditions, and analysis time. In this study, we examine the adequacy of XRF and ICP-ES/ICP-MS aqua-regia extractable (AR) results obtained for lab-type pretreated samples (N = 15) for Ti, Fe, Mn, Co, V, Pb, Zn, Cu, Cr, Mo, Sr, and As contents in soils under the impact of copper smelter and assess the equality of PTE contents induced health risk. The obtained results suggested that XRF reached definitive data quality level for As, Zn, and Mn and screening (quantitative) data quality level established for Cu, Pb, Fe, Mo, Cr, V, and Ti. Moreover, in some cases (i.e., for Ti) XRF overperformed AR indicating the high efficiency of XRF application when sparingly soluble mineral matricesare presented. At the same time, PTE induced health risk assessment at the established data quality level showed that equality of non-carcinogenic children health risk was observed for As, Zn, Cu, Pb, Mn, and V. The latter indicating the applicability of XRF to generate reliable base for risky sites identification and characterization.

Parental Investment Under Predation Threat in Incubating Common Eiders (Somateria mollissima): A Hormonal Perspective

Predation risk affects the costs and benefits of prey life-history decisions. Predation threat is often higher during reproduction, especially in conspicuous colonial breeders. Therefore, predation risk may increase the survival cost of breeding, and reduce parental investment. The impact of predation risk on avian parental investment decisions may be hormonally mediated by prolactin and corticosterone, making them ideal tools for studying the trade-offs involved. Prolactin is thought to promote parental care and commitment in birds. Corticosterone is involved in allostasis and may either mediate reduced parental investment (corticosterone-fitness hypothesis), or promote parental investment through a reallocation of resources (corticosterone-adaptation hypothesis). Here, we used these hormonal proxies of incubation commitment to examine the impact of predation risk on reproduction in common eiders (Somateria mollissima) breeding in the Baltic Sea. This eider population is subject to high but spatially and temporally variable predation pressure on adults (mainly by the white-tailed eagle Haliaeetus albicilla and introduced mammalian predators) and nests (by the adult predators and exclusive egg predators such as hooded crows Corvus cornix). We investigated baseline hormonal levels and hatching success as a function of individual quality attributes (breeding experience, female and duckling body condition), reproductive investment (clutch weight), and predation risk. We expected individuals nesting in riskier environments (i.e., on islands where predation on adults or nests is higher, or in less concealed nests) to reduce their parental investment in incubation, reflected in lower baseline prolactin levels and either higher (corticosterone-fitness hypothesis) or lower (corticosterone-adaptation hypothesis) baseline corticosterone levels. Contrary to our predictions, prolactin levels showed a positive correlation with nest predation risk. The unexpected positive relationship could result from the selective disappearance of low-quality females (presumably having low prolactin levels) from risky sites. Supporting this notion, female body condition and hatching success were positively correlated with predation risk on females, and baseline prolactin concentrations were positively correlated with duckling body condition, a proxy of maternal quality. In line with the corticosterone-adaptation hypothesis, baseline corticosterone levels increased with reproductive investment, and were negatively associated with nest predation risk. Hatching success was lower on islands where nest predation risk was higher, consistent with the idea of reduced reproductive investment under increased threat. Long-term individual-based studies are now needed to distinguish selection processes occurring at the population scale from individually plastic parental investment in relation to individual quality and variable predation risk.

Collateral flow at circle of Willis in healthy condition.

Experimental simulation of cerebrovascular system would be very beneficial tool to evaluate millions of human body cascade sequence. The Circle of Willis (CoW) recently named Cerebral Arterial Circle (CAC) is a main loop structure of cerebral circulatory system which positioned at the cranium base. In this research, we investigate cerebral artery flow pattern in cerebral arteries including afferent, Willisian, and efferent arteries of CAC emphasizing on communicating and connecting arteries which are main routes in CAC and as a risky sites when autoregulation is occurred in terminal parts of middle cerebral arteries (MCAs) by PMMA (Polymethyl methacrylate) chip and high quality camera which depict Sequential images. This novelty study analyze flow pattern in CAC that have been challenging subject area for many years which have investigated by scientists yet, because flow pattern in CAC indicate complication progression. This research tries to construct new platform in cerebral circulation analyzing method by reliable experimental in-vitro approach. The outcomes of this study demonstrate that communicating arteries especially anterior communicating artery (ACoA) is main artery in CAC flow distribution.

Temporal–Spatial Distribution of Risky Sites for Feeding Cattle in China Based on Temperature/Humidity Index

This study identifies risk areas for cattle husbandry based on temperature and a relative humidity index (THI) derived from climate data (1987 to 2016) at 839 meteorological stations in China using geostatistics (ordinary and indicator kriging) in the geographical information system (GIS). In general, monthly mean THI values were the highest in July and the lowest in January for all regions. The correlation analysis showed that there were negative relationships between THI values and latitude or elevation for the whole year (p < 0.01). The THI values were higher at low latitudes in coastal areas and at high latitudes in arid areas in summer. The healthy risk for cattle production varied depending on the time of the year and region. The study shows that cattle production is suitable throughout the whole year in the Qinghai-Tibet Plateau; from October to April for most areas, except the southern coastal areas; in May and September in Northeast China, North China, and parts of Northwest China; in June in Heilongjiang and Inner Mongolia. The information obtained in this study can provide a regional distribution of risk for the cattle industry in China.

Learning semantic information from Internet Domain Names using word embeddings

Word embeddings is a well-known set of techniques widely used in Natural Language Processing (NLP). These techniques are able to learn words’ semantic based on the distributional hypothesis which states that words that are used and occur in the same contexts tend to purport similar meanings.This paper explores the usage of word embeddings in a new scenario to create a Vector Space Model (VSM) for Internet Domain Names (DNS). Our goal is to find semantically similar domains only using information of DNS queries without any knowledge about the content of those domains.The results presented here have practical applications in many engineering activities including websites recommendations, identification of fraudulent or risky sites, parental-control systems and anomaly detection in network traffic analysis (among others).We use the distributional hypothesis to learn the semantic of domain names from users’ web navigation patterns, validating empirically that domain names that occur in the same web sessions tend to have similar semantic.We also test different word embeddings techniques: word2vec, app2vec (considering time intervals between DNS queries), and fastText (which includes sub-word information).Due to the characteristics of domain names, we found fastText as the best option for building a VSM for DNS, being 10.5% superior than word2vec with Skip-Gram which was the next best technique considering the Mean Average Precision at k (MAP@k) metric, which compares the most similar domains in our VSM with the most similar domains provided by a third party source, namely, similar sites service offered by Alexa Internet, Inc.

Mammalian nest predation induces small-scale nest site switching in territorial tawny owl (Strix aluco) females

Nest predation is a major factor affecting fitness in birds. Individuals are expected to respond to nest predation by selecting safe nesting sites and by moving away from risky sites. Thereby, perceived risk or experience of predation should lead to shifts in nest site selection. Experimental studies on behavioural and life-history consequences of nest predation have traditionally manipulated the risk of predation and studied the immediate consequences thereof. Fewer studies have however analysed the behavioural consequences of perceived predation risk to future breeding events and we know little about how sedentary territorial species respond to nest predation. We experimentally manipulated tawny owl (Strix aluco) breeding nest site choice by providing an additional alternative nest box within the territory, nearby the original nesting sites. The new nest box was provided either after a successful reproductive event (control group), or following a failed reproductive event caused by a nest predator (i.e. pine marten Martes martes, predated group).

Effects of bathing intensity, rainfall events, and location on the recreational water quality of stream pools in southern Ecuador.

Bathing in natural waters is a highly demanded recreational activity in tropical countries because of climatic conditions and availability of bathing sites; but, do users know the water quality of these sites? We determined the physicochemical and microbiological water quality of a highly used bathing site in southern Ecuador. We assessed how bather attendance, rainfall events, and pool location alters the recreational water quality (RWQ). Most of the parameters measured in the stream pools did not accomplish the Ecuadorian and international regulations for recreational water quality. Microbiological water quality diminishes from upstream to downstream pools because of human activities and bathing intensity having potential effects on bather health and eco-touristic development. We found that an increase of bathers is strongly associated with a growing concentration of Escherichia coli. It is suggested better land-use practices and review thoroughly the Ecuadorian regulation to assure a healthy RWQ. Further efforts are needed to identify more risky bathing sites, determine pollution sources, and establish a long-term monitoring program to support the touristic development in countries looking for diversifying their economy.

Probing of mortality rate by staying alive: The growth‐reproduction trade‐off in a spatially heterogeneous environment

Abstract In many annual plants, mollusks, crustaceans and ectothermic vertebrates, growth accompanies reproduction. The growth curves of these organisms often exhibit a complex shape, with episodic cessations or accelerations of growth occurring long after maturation. The mixed allocation to growth and reproduction has poorly understood adaptive consequences, and the life‐history theory does not explain if complex growth in short‐lived organisms can be adaptive. We model the trade‐off between growth and reproduction in a short‐lived organism evolving in a metapopulation. Individuals occupy risky or safe sites throughout their lives, but are uncertain regarding the risk of death. Modelled organisms are allowed to grow and produce offspring at specified time points (moults), although we also consider scenarios that approximate continuous growth and reproduction. Certain combinations of risky to safe sites select for strategies with mixed allocation to growth and reproduction that bet‐hedge offspring production in safe and risky sites. Our model shows that spatially heterogeneous environments select for mixed allocation only if safe sites do not become the prevailing source of recruits, for example, when risky sites are frequent. In certain conditions, growth curves are multi‐phasic, with allocation to growth that stops, remains constant or accelerates during adult life. The resulting complex growth curves are more likely to evolve in short‐lived organisms that moult several times per adult life. Our work shows that spatial heterogeneity can select for growth that accompanies reproduction and provides insights into the adaptive significance of complex growth curves. Short‐lived crustaceans are particularly predisposed to exhibit complex growth patterns as an adaptive response to spatially heterogeneous environments. Our results suggest that standard statistical growth models assuming adult growth rate to only decelerate over life are not well suited to approximate growth curves of short‐lived crustaceans. A free Plain Language Summary can be found within the Supporting Information of this article.

Proactive behavior-based system for controlling safety risks in urban highway construction megaprojects

Abstract Urban highway construction megaprojects are commonly beset by significant and dynamic safety risks because of their large size, the scattered nature of the works involved, compressed construction schedules, technical difficulties and numerous participants. However, traditional on-site safety inspection cannot fully address all challenges, particularly those with behavior-based safety (BBS) risks. To deal with these challenges, this study describes the novel use of the proactive construction management system (PCMS) with a third-party safety inspection program. The definition, abstraction and implementation processes of the PCMS-aided third-party inspection program are demonstrated and tested through a case study of the Shanghai Central Loop Pudong highway construction project with multi-section sites. Based on a “before and after” comparative study, quantitative and qualitative data are triangulated to evaluate variations in the effectiveness of third-party inspection programs with and without the PCMS aided at the macro, meso, and micro levels. Results indicate the usefulness of the novel idea that applies the PCMS as a part of a third-party inspection program to improve BBS risk control on certain risky sites and incorporates its feedback into third-party inspection on all section sites to strengthen the overall safety training, safety inspection, and timely safety risk responses. These results not only provide an increased understanding of the role of PCMS in the safety management of highway megaprojects and the guidelines required for its future application but also serve as a precursor to future research into megaproject safety management.

Foragers of sympatric Asian honey bee species intercept competitor signals by avoiding benzyl acetate from Apis cerana alarm pheromone

While foraging, animals can form inter- and intraspecific social signalling networks to avoid similar predators. We report here that foragers of different native Asian honey bee species can detect and use a specialized alarm pheromone component, benzyl acetate (BA), to avoid danger. We analysed the volatile alarm pheromone produced by attacked workers of the most abundant native Asian honey bee, Apis cerana and tested the responses of other bee species to these alarm signals. As compared to nest guards, A. cerana foragers produced 3.38 fold higher levels of BA. In foragers, BA and (E)-dec-2-en-1-yl acetate (DA) generated the strongest antennal electrophysiological responses. BA was also the only compound that alerted flying foragers and inhibited A. cerana foraging. BA thereby decreased A. cerana foraging for risky sites. Interestingly, although BA occurs only in trace amounts and is nearly absent in sympatric honeybee species (respectively only 0.07% and 0.44% as much in A. dorsata and A. florea), these floral generalists detected and avoided BA as strongly as they did to their own alarm pheromone on natural inflorescences. These results demonstrate that competing pollinators can take advantage of alarm signal information provided by other species.

Human health risk assessment and riskiest heavy metal origin identification in urban soils of Yerevan, Armenia

The pollution of urban soils by heavy metals remains a topical issue because of the risks it represents to human health. Heavy metal pollution levels of Yerevan's soils were evaluated using Pollution index and Enrichment factor, while associated health risk was assessed by US EPA model. The heavy metals with significant amount of PI > 1 values were observed for V (100%), Cr (95.4%), Ni (92.5%), Cu (95.6%), Zn (92.9%), Hg (89.0%), Pb (99.9%), As (72.0%), and Ba (61.6% of samples). EF showed that Yerevan topsoils were significantly contaminated with Hg, and moderately contaminated with V, Ni, Cu, Zn, Cr, and As. Topsoils near the smelting plants of molybdenum concentrate have moderately to extremely high contamination levels for Mo. Topsoils were moderate to extremely highly contaminated with Pb, too. The high amounts of samples with heavy metal contents greater than Maximum Acceptable Concentrations were observed for Pb, Cr, Zn, Ni, and Cu. Pb and Cr exceeded corresponding Soil Screening Levels in 3.39% and 2.43% of samples, correspondingly. The risk assessment showed children's multi-elemental non-carcinogenic risk and low level of arsenic carcinogenic risk in the whole Yerevan. The riskiest element was Pb which high contents in 72 risky sites correlate only with the metals having a natural origin. Moreover, its main source is historically polluted soils and Pb supposed to be redistributed in the city environment linked to the sorption complexes of Fe and Mn oxides.

Relationship between peripheral insertion site and catheter-related phlebitis in adult hospitalized patients: a systematic review.

To explore the relationship between the anatomical site of peripheral venous catheterization and risk of catheter-related phlebitis. Peripheral venous catheterization is frequently associated with phlebitis. Recent guidelines, recommend the use of an upper-extremity site for catheter insertion but no univocal consensus exists on the anatomical site with lower risk of phlebitis. Systematic review. We searched Medline (PubMed) and CINAHL (EBSCOhost) databases until the end of January 2017. We also reviewed the reference lists of retrieved articles and gray literature was excluded. Searches were limited to articles published in English with no restriction imposed to date of publication. The primary outcome was the incidence of phlebitis associated with anatomical site of peripheral catheterization. We included randomized controlled trials and observational studies on adult patients who required a peripheral catheter for the administration of medi- cation, intermittent or continuous fluid infusion. Antecubital fossa veins are associated with lower phlebitis rates, while hands veins are the most risky sites to develop phlebitis. There is no consensus regarding vein in forearm. Choosing the right anatomical site to insert a peripheral venous catheter is important to decrease phlebitis rate. Further studies should compare indwelling time in different anatomical sites with phlebitis rate. A more standardized approach in defining and assessing phlebitis among studies is recommended.

Assessment of spatial and seasonal changes in groundwater nitrate pollution of agricultural lands through ordinary and indicator kriging techniques

ABSTRACTGeostatistical approaches (ordinary kriging (OK) and indicator kriging (IK)) were used in this study to investigate the spatial and temporal variations in groundwater nitrate concentrations in Çarşamba plain of Turkey. Groundwater samples were taken in April 2012, July 2012, September 2012 and March 2013 from 78 groundwater wells. The experimental semivariograms were often fitted well by a Gauss model for April 2012 and September 2012, whereas a spherical model was fitted to experimental semivariograms for July 2012 and March 2013. Spatial distribution maps revealed that groundwater nitrate concentrations were above the threshold value of 50 mg L−1 specified for drinking water in 4.3% of the study area in April 2012, 40.8% in July 2012, 32.8% in September 2012 and 19.1% in March 2013. Probability maps created with IK showed that 3.1% and 3.2% of the total area had very strong probability (0.8–1.0) of exceeding the threshold nitrate concentration in July 2012 and September 2012, respectively. Current findings revealed that groundwater nitrate concentrations changed seasonally and increased much more in summer. It was concluded that OK and IK may yield significant outcomes for groundwater management, identification of risky sites for potential pollution and identification of the sites with excessive fertilizer uses.

Titrating the Cost of Plant Toxins Against Predators: a Case Study with Common Duikers, Sylvicapra grimmia.

Foragers face many variables that influence their food intake. These may include habitat structure, time, climate, resource characteristic, food quality, and plant defenses. I conducted foraging experiments using common duikers that involved: 1) testing the effect of plant toxins on foraging, and 2) titrating toxin intake against safety. I used giving up densities (GUDs, food remaining after foraging) to test for selection among trays containing alfalfa pellets treated with water, with 10% oxalic acid, or 10% quebracho tannin. Pairs of trays were placed within islands of woody vegetation and out in open grass. I also conducted a titration experiment by offering the duikers a choice between a patch with water-treated pellets placed at a risky site, or a patch with one of three oxalic acid-treated pellets at a safe site. This made it possible to determine the concentration of oxalic acid at which the cost of toxin in the safe site equals the predation cost at the risky site. The common duikers showed no selectivity among the three treatments at 10% concentration, however, GUDs in the open grass (i.e., safe) were significantly lower than in the wooded islands (i.e., risky). As the oxalic acid concentration increased at the safe sites, the duiker's food intake from the risky sites increased significantly. The results demonstrate that foraging hazards may come in different forms such as predation and plant toxins, and their interactions may alter habitat use, foraging patterns, and perceptions of risk. These variables occur under natural situations, altering the overall habitat quality.

Analysis of flow and LDL concentration polarization in siphon of internal carotid artery: Non-Newtonian effects

Carotid siphon is known as one of the risky sites among the human intracranial arteries, which is prone to formation of atherosclerotic lesions. Indeed, scientists believe that accumulation of low density lipoprotein (LDL) inside the lumen is the major cause of atherosclerosis. To this aim, three types of internal carotid artery (ICA) siphon have been constructed to examine variations of hemodynamic parameters in different regions of the arteries. Providing real physiological conditions, blood considered as non-Newtonian fluid and real velocity and pressure waveforms have been employed as flow boundary conditions. Moreover, to have a better estimation of risky sites, the accumulation of LDL particles has been considered, which has been usually ignored in previous relevant studies. Governing equations have been discretized and solved via open source OpenFOAM software. A new solver has been built to meet essential parameters related to the flow and mass transfer phenomena. In contrast to the common belief regarding negligible effect of blood non-Newtonian behavior inside large arteries, current study suggests that the non-Newtonian blood behavior is notable, especially on the velocity field of the U-type model. In addition, it is concluded that neglecting non-Newtonian effects underestimates the LDL accumulation up to 3% in the U-type model at the inner side of both its bends. However, in the V and C type models, non-Newtonian effects become relatively small. Results also emphasize that the outer part of the second bend at the downstream is also at risk similar to the inner part of the carotid bends. Furthermore, from findings it can be implied that the risky sites strongly depend on the ICA shape since the extension of the risky sites are relatively larger for the V-type model, while the LDL concentrations are higher for the C-type model.

A “death trap” in the landscape of fear

Abstract 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-ungulate interactions is biased by studies from highly heterogeneous landscapes (e.g. the Yellowstone National Park). Due to a high availability of refuges and foraging sites in such landscapes, prey are able to reduce predation risk by showing habitat shifts. Besides the spatial heterogeneity at the landscape scale, the ungulate response to predation risk can be affected by the hunting mode (stalking vs. cursorial) of the predator. We propose that prey cannot easily avoid predation risk by moving to less risky habitats in more homogenous landscapes with concentrated food resources, especially where the large carnivores’ assemblage includes both stalking and cursorial species. No distinct refuges for prey may occur in such landscapes due to equally high accessibility to predators in all habitats, while concentrated resources make prey distribution more predictable. We discuss a model of a densely forested landscape based on a case study of the Białowieża Primeval Forest, Poland. Within this landscape, ungulates focus their foraging activity on small food-rich forest gaps, which turn out to be “death traps” as the gaps are primarily targeted by predators (stalking lynx and cursorial wolf) while hunting. No alternative of moving to low predation risk areas exist for prey due to risk from wolves in surrounding closed-canopy forest. As a result, the prey is exposed to constant high predation pressure in contrast to heterogeneous landscapes with less concentrated resources and more refuge areas. Future research should focus on explaining how ungulates are coping with predation risk in these landscapes that offer little choice of escaping predation by considering behavioural and physiological (e.g. metabolic, hormonal) responses.