scholarly journals Severe Conservation Risks of Roads on Apex Predators

Author(s):  
Itxaso Quintana ◽  
Edgar Fernando Cifuentes ◽  
Jeffrey A. Dunnink ◽  
Maria Ariza ◽  
Daniela Martinez-Medina ◽  
...  

Abstract The global expansion of road networks threatens apex predator conservation and ecosystem functioning. This occurs through wildlife-vehicle collisions, habitat loss and fragmentation, reduced genetic connectivity and increased poaching. We reviewed road impacts on 36 apex predator species and created a new index to assess their current vulnerability to roads. Our findings reveal all apex predators are currently exposed to road impacts. Five of the nine most vulnerable species occur in Asia, the sloth bear being the most severely affected. Critically endangered species such as the Iberian lynx and red wolf are severely affected by roads. Using a widely applicable novel index we assessed the potential impact of future roads on apex predators in three areas: the Brazilian Amazon, Africa, and Nepal. Proposed roads will have an impact on forest predators over the whole Brazilian Amazon. In Africa and Nepal, roads will fragment the distribution ranges of nine and seven apex predators, respectively. Roughly 500 protected areas will be intersected by roads, threatening core apex predator habitat. Therefore, we advocate the need for rigorous road development planning to apply effective mitigation measures as an urgent priority, and to avoid construction in wilderness areas and predator strongholds.

Mammalia ◽  
2019 ◽  
Vol 83 (5) ◽  
pp. 415-427 ◽  
Author(s):  
Flávia P. Tirelli ◽  
Thales R.O. de Freitas ◽  
Fernanda Michalski ◽  
Alexandre R. Percequillo ◽  
Eduardo Eizirik

Abstract Accurate identification of predator species is a critical requirement to investigate their diet using faecal samples. We used non-invasive sampling and two methods of predator identification to investigate the diets of sympatric carnivores in a highly deforested region of the Brazilian Amazon. Of 108 scats, 81 could be identified at the species level using DNA sequencing and/or trichology. The former performed better than the latter (81.5% vs. 54.3% of the identified samples), and results were quite congruent (89.7% concordance in the 29 samples that could be assessed with both approaches). Nine species were identified, out of which four (crab-eating fox, ocelot, puma and jaguar) presented a sufficient number of samples to allow dietary analyses. The crab-eating fox was the most generalist (BA=0.92); ocelots focused on small- to medium-sized prey; pumas fed mostly on medium-sized items; and jaguars mostly targeted large-sized prey. A considerable overlap was observed between ocelots and pumas in all estimations (O=0.47–0.83). The presence of jaguars in the same region could be driving pumas to select medium- and small-sized prey. The results of this study highlight the importance of reliable predator identification and the need for in-depth ecological studies in areas where carnivore species are sympatric.


2020 ◽  
Vol 287 (1938) ◽  
pp. 20202202
Author(s):  
L. Mark Elbroch ◽  
Jake M. Ferguson ◽  
Howard Quigley ◽  
Derek Craighead ◽  
Daniel J. Thompson ◽  
...  

Top-down effects of apex predators are modulated by human impacts on community composition and species abundances. Consequently, research supporting top-down effects of apex predators occurs almost entirely within protected areas rather than the multi-use landscapes dominating modern ecosystems. Here, we developed an integrated population model to disentangle the concurrent contributions of a reintroduced apex predator, the grey wolf, human hunting and prey abundances on vital rates and abundance of a subordinate apex predator, the puma. Increasing wolf numbers had strong negative effects on puma fecundity, and subadult and adult survival. Puma survival was also influenced by density dependence. Overall, puma dynamics in our multi-use landscape were more strongly influenced by top-down forces exhibited by a reintroduced apex predator, than by human hunting or bottom-up forces (prey abundance) subsidized by humans. Quantitatively, the average annual impact of human hunting on equilibrium puma abundance was equivalent to the effects of 20 wolves. Historically, wolves may have limited pumas across North America and dictated puma scarcity in systems lacking sufficient refugia to mitigate the effects of competition.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260046
Author(s):  
Patrick Nalepka ◽  
Paula L. Silva ◽  
Rachel W. Kallen ◽  
Kevin Shockley ◽  
Anthony Chemero ◽  
...  

Social animals have the remarkable ability to organize into collectives to achieve goals unobtainable to individual members. Equally striking is the observation that despite differences in perceptual-motor capabilities, different animals often exhibit qualitatively similar collective states of organization and coordination. Such qualitative similarities can be seen in corralling behaviors involving the encirclement of prey that are observed, for example, during collaborative hunting amongst several apex predator species living in disparate environments. Similar encirclement behaviors are also displayed by human participants in a collaborative problem-solving task involving the herding and containment of evasive artificial agents. Inspired by the functional similarities in this behavior across humans and non-human systems, this paper investigated whether the containment strategies displayed by humans emerge as a function of the task’s underlying dynamics, which shape patterns of goal-directed corralling more generally. This hypothesis was tested by comparing the strategies naïve human dyads adopt during the containment of a set of evasive artificial agents across two disparate task contexts. Despite the different movement types (manual manipulation or locomotion) required in the different task contexts, the behaviors that humans display can be predicted as emergent properties of the same underlying task-dynamic model.


2019 ◽  
Vol 30 (5) ◽  
pp. 1324-1335 ◽  
Author(s):  
Carolyn R Shores ◽  
Justin A Dellinger ◽  
Eric S Newkirk ◽  
Shannon M Kachel ◽  
Aaron J Wirsing

Abstract Apex predators can influence ecosystems through density and behaviorally mediated effects on herbivores and mesopredators. In many parts of the world, apex predators live in, or are returning to, landscapes that have been modified by people; so, it is important to understand their ecological role in anthropogenic landscapes. We used motion-activated game cameras to compare the activity patterns of humans and 2 mesopredators, coyotes (Canis latrans) and bobcats (Lynx rufus), in areas with and without an apex predator, the gray wolf (Canis lupus), in a multiuse landscape of the northwestern United States. In areas with wolves, there was a significant increase in temporal niche overlap between the mesopredators owing to higher levels of coyote activity at all time periods of the day. Temporal overlap between mesopredators and humans also increased significantly in the presence of wolves. Coyotes exposed to wolves increased their activity during dawn, day, and dusk hours. The increase in coyote activity was greatest during the day, when wolves were least active. The direction of change in bobcat activity in areas with wolves was opposite to coyotes, suggesting a behaviorally mediated cascade between wolves, coyotes, and bobcats, although these findings would need to be confirmed with further research. Our findings suggest that mesopredators in human-dominated systems may perceive humans as less dangerous than apex predators, that humans may be more likely to encounter mesopredators in areas occupied by top predators, and that behaviorally mediated effects of apex predators on mesopredators persist in human-dominated landscapes.


2021 ◽  
Vol 75 (2) ◽  
Author(s):  
Mariana Rossa ◽  
Sandro Lovari ◽  
Francesco Ferretti

Abstract Spatial and temporal occurrence can mediate behavioural interactions between apex predators, mesocarnivores and herbivores. Predators should adapt their activity to that of prey, whereas predator avoidance would be expected to influence activity patterns and space use of prey and smaller competitors. We evaluated interspecific spatiotemporal relationships in a prey-rich community including an apex predator (the wolf), three wild ungulates and several smaller herbivores/mesocarnivores, through camera trapping. All considered species (i.e. wolves and potential prey/smaller competitors: wild boar, fallow deer, roe deer, crested porcupine, red fox and European badger) were active especially at night and/or twilight. Among wild ungulates, the wolf showed the greatest temporal overlap with the wild boar and the lowest one with the least abundant and used of them, i.e. the roe deer. The main prey (i.e. the fallow deer) showed more diurnal activity and a lower temporal overlap with the predator in sites with high wolf activity than in low-activity ones. Among mesocarnivores, the red fox showed extensive temporal overlap with the wolf: the overlap between the two canids was greater in sites intensively used by this apex predator than in sites with low wolf activity, supporting a concurrent study which suggested a potential for facilitative—rather than competitive—interactions. Spatiotemporal relationships suggest complex interactions between the apex predator, prey and smaller carnivores, for which a substantial temporal or spatial association was often supported. Significance statement There is a growing interest in the influence of apex predators on ecosystems through their effects on the behaviour of prey and smaller carnivores, especially in the light of the ongoing recovery of large carnivores in temperate areas. Predators should synchronise their activity to that of prey; conversely, prey and smaller carnivores would be expected to avoid predators. In a rich community including the wolf, three wild ungulates and several mesomammals, we detected (i) a substantial temporal overlap between wolves and wild boar, porcupines and mesocarnivores; (ii) a negative temporal association between the predator and its main prey (i.e. the fallow deer) and (iii) a great temporal overlap between the wolf and the red fox. We provide a baseline to evaluate temporal changes of predator-prey-mesocarnivore behavioural interactions along with variations of carnivore-prey densities.


2019 ◽  
Author(s):  
Ian James Radford ◽  
Leigh-Ann Woolley ◽  
Chris R. Dickman ◽  
Ben Corey ◽  
Dane Trembath ◽  
...  

AbstractApex predators are fundamentally important in regulating many ecosystems, and perturbations of their populations are frequently implicated in ecosystem declines or collapses. In considering small mammal declines in northern Australia, most attention has focused on interactions between a mammalian apex predator—the dingoCanis dingo—and a meso-predator, the feral cat—Felis catus. Little consideration has been given to the possible implications of changed reptilian predator assemblages resulting from invasion by a toxic anuran invader, the cane toad (Rhinella marina), on small mammals. We used reptile removal records from licenced reptile catchers in three widely spaced towns in the savannas of northern Australia to explore potential impacts of toads on apex and meso-predatory snakes and large lizards. In addition, simultaneous fauna survey data from one town with reptile removal records, coinciding with toad invasion, were used to identify cascading impacts through the savanna ecosystem. Intervention analyses revealed empirical linkages between toad invasion, apex predator declines, meso-predator increases and declines of small mammals and other prey groups. Based on the timing and strength of intervention we postulate a novel conceptual model linking recent mammal declines with trophic cascades following toad invasion, where the loss of large, anurophagous (toad-eating) reptilian apex predators allowed increases in mammal-eating meso-predatory snakes. The conceptual model is discussed in relation to prevailing hypotheses regarding northern Australia’s dramatic small mammal declines. Future studies will need to quantify these putative interactions and test their comparative importance so that appropriate management can be implemented to stem the ongoing losses of mammal fauna.


2021 ◽  
Author(s):  
Jérôme G. Prunier ◽  
Géraldine Loot ◽  
Charlotte Veyssiere ◽  
Nicolas Poulet ◽  
Simon Blanchet

ABSTRACTRivers are heavily fragmented by man-made instream barriers such as dams and weirs. This hyper-fragmentation is a major threat to freshwater biodiversity and restoration policies are now adopted worldwide to mitigate these impacts. However, there is surprisingly little feedback on the efficiency of barrier mitigation measures in restoring riverine connectivity, notably for non-migratory fish species. Here, we implemented a “before-after genetic monitoring” of the restoration of 11 weirs in France using a dedicated genetic index of fragmentation (the FINDEX), with a focus on five fish species from two genera. We found that most obstacles actually had a significant impact on connectivity before restoration, especially the highest and steepest ones, with an overall barrier effect of about 51% of the maximal theoretical impact. Most importantly, we demonstrated for the first time that mitigation measures such as dam removal or fish pass creation significantly and rapidly improved connectivity, with –for some barriers-a complete recovery of the genetic connectivity in less than twelve months. Our study provides a unique and strong proof-of-concept that barrier removal is an efficient strategy to restore riverine connectivity and that molecular tools can provide accurate measures of restoration efficiency within a few months.Graphical Abstract


2016 ◽  
Vol 7 (5) ◽  
pp. 557-563 ◽  
Author(s):  
Aja Tumavičė ◽  
Alfredas Laurinavičius

All over the world railways are of the least-polluting vehicles, and they became increasingly popular. However, the noise emission from railway infrastructure is the most problematic issue, especially at the development planning stage. This article presents analysis of Lithuanian regulations for railway design in the aspect of reduction of acoustic noise. It analyses regulations, which are mandatory for Lithuanian railway designers and builders. In addition, the overview of regulations’provisions, which are related to noise mitigation measures, are presented. Pasaulyje vis labiau populiarėja kelionės geležinkeliais, kurie yra viena iš mažiausiai taršių transporto priemonių. Nuo geležinkelio infrastruktūros sklindantis triukšmas yra viena didžiausių problemų, ypač planuojant jų plėtrą. Straipsnyje pristatyta Lietuvos norminių techninių dokumentų, skirtų geležinkeliams projektuoti, analizė akustinio triukšmo mažinimo aspektu. Buvo išanalizuoti norminiai techniniai dokumentai, kurie privalomi naudoti Lietuvoje geležinkelių projektuotojams ir geležinkelių tiesėjams, bei apžvelgta, kokios yra juose nuostatos, susijusios su triukšmą mažinančiomis priemonėmis.


ZooKeys ◽  
2020 ◽  
Vol 954 ◽  
pp. 109-156 ◽  
Author(s):  
Vanessa Parra ◽  
Pedro M. Sales Nunes ◽  
Omar Torres-Carvajal

Four new species of Pholidobolus lizards are described from poorly explored areas in the Andes of southern Ecuador based on morphological and genetic evidence. Among other morphological characters, Pholidobolus sameksp. nov. and P. condorsp. nov. differ from their congeners in having green dorsolateral stripes on head. Males of P. condorsp. nov. differ from those of P. sameksp. nov. in having reddish flanks and venter. P. dolichoderessp. nov. is distinguished by having a long neck, with more scales between orbit and tympanum, whereas P. fascinatussp. nov. is distinguished by lacking enlarged medial scales on collar and a conspicuous vertebral stripe. In addition, the phylogenetic position of the new species is inferred using DNA sequences of mitochondrial and nuclear genes. The phylogeny supports strongly monophyly of each of the new species and renders P. macbrydei paraphyletic and split into six subclades. Available data suggest that the new species have restricted distribution ranges (< 100 km2 each), and it is proposed that their classification be as Data Deficient or Critically Endangered species. The results reveal unexpected levels of diversity within Pholidobolus in the Andes of southern Ecuador and highlight the importance of improving scientific collections and conservation efforts in this area.


2013 ◽  
Vol 40 (5) ◽  
pp. 427 ◽  
Author(s):  
Bronwyn Isaac ◽  
John White ◽  
Daniel Ierodiaconou ◽  
Raylene Cooke

Context Urbanisation is one of the most damaging landscape-scale disturbance processes leading to significant and potentially irreversible changes in biodiversity. How apex predators respond to urbanisation is poorly understood, largely because of their low density and low detectability. Given the important functional roles of apex predators in ecosystems, it is critical that research investigates how they respond to urbanisation, and how urban systems can be designed to better support apex predators. Aims The present research aims to examine how an avian apex predator, the powerful owl, responds to a complete urban–forest gradient in southern Victoria, Australia. Specifically, the research aims to understand the environmental attributes that drive habitat suitability for powerful owls across the urban–forest gradient. Methods Using a total of 683 independent field- and atlas-derived records of powerful owls across the study site, the research takes a presence-only modelling approach. The presence points were modelled against a series of geospatial variables that were determined a priori on the basis of the known ecology of powerful owls. Key results Potential powerful owl habitat declined in a dramatic fashion in response to increasing levels of urbanisation, ranging from 76% of the forest landscape to 21% of the urban landscape. Powerful owl habitat availability across the urban–forest gradient is positively influenced by tree cover, productivity (normalised difference vegetation index) and proximity to river systems and riparian vegetation. Conclusions Presence-only modelling has provided a useful way for investigating the response of an apex predator to a gradient of urbanisation. Although powerful owl habitat availability is negatively reduced by urbanisation, there is significant scope to manage urban landscapes to either maintain or improve the availability of habitat across the gradient. Implications High resource-requiring species, such as apex predators, have the capacity to be detrimentally affected by urbanisation processes. Presence-only modelling, however, provides a useful tool for investigating how these difficult-to-detect species are affected by urbanisation, and ultimately inform how landscapes can be managed to maximise habitat availability for apex predators.


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