scholarly journals Inference in road ecology research: what we know versus what we think we know

2020 ◽  
Vol 16 (7) ◽  
pp. 20200140 ◽  
Author(s):  
Fernanda Z. Teixeira ◽  
Trina Rytwinski ◽  
Lenore Fahrig
Keyword(s):  
Habitat Quality ◽  
Road Ecology ◽  
Relative Importance ◽  
Road Kill ◽  
Single Mechanism ◽  
Traffic Impacts ◽  
Wildlife Populations

Roads and traffic impacts on wildlife populations are well documented. Three major mechanisms can cause them: reduced connectivity, increased mortality and reduced habitat quality. Researchers commonly recommend mitigation based on the mechanism they deem responsible. We reviewed the 2012–2016 literature to evaluate authors' inferences, to determine whether they explicitly acknowledge all possible mechanisms that are consistent with their results. We found 327 negative responses of wildlife to roads, from 307 studies. While most (84%) of these responses were consistent with multiple mechanisms, 60% of authors invoked a single mechanism. This indicates that many authors are over-confident in their inferences, and that the literature does not allow estimation of the relative importance of the mechanisms. We found preferences in authors' discussion of mechanisms. When all three mechanisms were consistent with the response measured, authors were 2.4 and 2.9 times as likely to infer reduced habitat quality compared to reduced connectivity or increased mortality, respectively. When both reduced connectivity and increased mortality were consistent with the response measured, authors were 5.2 times as likely to infer reduced connectivity compared to increased mortality. Given these results, road ecologists and managers are likely over-recommending mitigation for improving habitat quality and connectivity, and under-recommending measures to reduce road-kill.

The relative importance of habitat quality and landscape context for reptiles in regenerating landscapes

2016 ◽  
Vol 193 ◽  
pp. 37-47 ◽  
Author(s):  
Melissa J. Bruton ◽  
Martine Maron ◽  
Craig E. Franklin ◽  
Clive A. McAlpine
Keyword(s):  
Habitat Quality ◽  
Landscape Context ◽  
Relative Importance

scholarly journals When environmentally persistent pathogens transform good habitat into ecological traps

2016 ◽  
Vol 3 (3) ◽  
pp. 160051 ◽  
Author(s):  
Clinton B. Leach ◽  
Colleen T. Webb ◽  
Paul C. Cross
Keyword(s):  
Habitat Quality ◽  
Transmission Rate ◽  
Pathogen Transmission ◽  
Ecological Trap ◽  
Patch Occupancy ◽  
Environmental Persistence ◽  
High Quality ◽  
Patch Occupancy Model ◽  
Wildlife Populations ◽  
Persistent Pathogens

Habitat quality plays an important role in the dynamics and stability of wildlife metapopulations. However, the benefits of high-quality habitat may be modulated by the presence of an environmentally persistent pathogen. In some cases, the presence of environmental pathogen reservoirs on high-quality habitat may lead to the creation of ecological traps, wherein host individuals preferentially colonize high-quality habitat, but are then exposed to increased infection risk and disease-induced mortality. We explored this possibility through the development of a stochastic patch occupancy model, where we varied the pathogen’s virulence, transmission rate and environmental persistence as well as the distribution of habitat quality in the host metapopulation. This model suggests that for pathogens with intermediate levels of spread, high-quality habitat can serve as an ecological trap, and can be detrimental to host persistence relative to low-quality habitat. This inversion of the relative roles of high- and low-quality habitat highlights the importance of considering the interaction between spatial structure and pathogen transmission when managing wildlife populations exposed to an environmentally persistent pathogen.

Koala feeding and roosting trees in the Campbelltown area of New South Wales.

2001 ◽  
Vol 23 (2) ◽  
pp. 173 ◽  
Author(s):  
AF Sluiter ◽  
RL Close ◽  
SJ Ward
Keyword(s):  
Habitat Quality ◽  
New South ◽  
Relative Importance ◽  
Radio Tracking ◽  
Separate Study ◽  
Phascolarctos Cinereus ◽  
Faecal Pellets ◽  
Dietary Preference ◽  
South Wales ◽  
Preferred Species

IN assessing habitat quality for koalas (Phascolarctos cinereus), the relative importance of trees used for food and for roosting must be established. Robbins and Russell (1978) and Hindell et al. (1985) suggested that trees in which P. cinereus roosted by day reliably predicted the trees they browsed. Tun (1993) and Hasegawa (1995), however, using leaf cuticle analysis of P. cinereus faecal pellets, questioned that suggestion . Phillips and Callaghan (2000) investigated preferences of P. cinereus in the Campbelltown area, 40 km southwest of Sydney, by recording the presence of faecal pellets beneath trees in survey quadrats. They concluded that Eucalyptus punctata (grey gum) and E. agglomerata (blue-leaved stringy bark) were preferred species on shale-based soils. However, this method still does not distinguish between trees used for roosting and those used for feeding. Cuticle analysis was therefore used at Campbelltown as a test of dietary preference (Table 1). These data on species use were compared with sightings from a radio-tracking study of the same individuals (Table 2), in a separate study (Ward 2002).

scholarly journals Predicting spatial and seasonal patterns of wildlife-vehicle collisions in high-risk areas

2021 ◽  
Author(s):  
Hanh K.D. Nguyen ◽  
Jessie C. Buettel ◽  
Matthew W. Fielding ◽  
Barry W. Brook
Keyword(s):  
Road Ecology ◽  
Additive Model ◽  
Predictive Modelling ◽  
Encounter Rate ◽  
Road Mortality ◽  
Vehicle Collisions ◽  
Road Kill ◽  
Management Interventions ◽  
Forested Areas ◽  
High Level

AbstractContextVehicle collisions with wildlife can injure or kill animals, threaten human safety, and threaten the viability of rare species. This has led to a focus in road-ecology research on identifying the key predictors of ‘road-kill’ risk, with the goal of guiding management to mitigate its impact. However, because of the complex and context-dependent nature of the causes of risk exposure, modelling road-kill data in ways that yield consistent recommendations has proven challenging.AimHere we used a novel multi-model machine-learning approach to identify the spatio-temporal predictors, such as traffic volume, road shape, surrounding vegetation and distance to human settlements, associated with road-kill risk.MethodsWe collected data on the location, identity and size of each road mortality across four seasons along eight roads in southern Tasmania – a ‘road-kill hotspot’ of management concern. We focused on three large-bodied and frequently impacted crepuscular Australian marsupial herbivore species, the rufous-bellied pademelon (Thylogale billardierii), Bennett’s wallaby (Macropus rufogriseus) and the bare-nosed wombat (Vombatus ursinus). We fit the point-location data using ‘lasso-regularization’ of a logistic generalized linear model (LL-GLM) and out-of-bag optimization of a decision-tree-based ‘random forests’ (RF) algorithm.ResultsThe RF model, with high-level feature interactions, yielded superior results to the linear additive model, with a RF classification accuracy of 84.8% for the 871 road-kill observations and a true skill statistic of 0.708, compared to 61.2% and 0.205 for the LL-GLM.ConclusionsForested areas with no roadside barrier fence along curved sections of road posed the highest risk to animals. Seasonally, the frequency of wildlife-vehicle collisions increased notably for females during oestrus, when they were more dispersive and so had a higher encounter rate with roads.ImplicationsThese findings illustrate the value of using data-driven approaches to predictive modelling, as well as offering a guide to practical management interventions that can mitigate road-related hazards.

scholarly journals Environmental Factors Determinate Roadkill Levels of the Endemic Iberian Species, Iberian Hare (Lepus Granatensis)

2021 ◽  
Author(s):  
Jesús Duarte ◽  
David Romero ◽  
Pablo Rubio ◽  
Miguel Ángel Farfán ◽  
Julia Fa
Keyword(s):  
Spatial Patterns ◽  
Landscape Heterogeneity ◽  
Road Ecology ◽  
Future Directions ◽  
Road Kill ◽  
Vehicle Accidents ◽  
Small Game ◽  
Lepus Granatensis ◽  
Hunting Quotas ◽  
Iberian Hare

Abstract Lepus granatensis is an Iberian Peninsula endemic species and one of the most important small game species. We surveyed Iberian hare-vehicle accidents in roads network in southern Spain, analysing the Mediterranean landscape, the main habitats of this species. We recorded roadkill of roads during 6-month, compared hare roadkill densities to hare hunting yields. We analyzed the spatial patterns and factors that could be influencing the hare road kill. We detected blackspots of hare road kill in areas with high landscape heterogeneity and included embankments, intersections roads and high traffic intensity. The hare roadkill ranged between 6% and 41% of the annual harvest of hares killed on neighbouring hunting estates. We therefore consider it highly relevant to take into account the hare road kill, especially in hare hunting areas, suggesting to gamekeepers and managers addressing the issue of road kill of hares. It would be necessary that hunting quotas be adjusted in territories where the additive effect of these non-natural hare mortalities converge. Results point to future directions for applied research in road ecology, which would include demographic compensation and roadkill mitigation. Our methodology could be of wide use to identify lagomorphs’ road kill blackspots by analysing environmental spatial patterns.

Relative importance of resource quantity, isolation and habitat quality for landscape distribution of a monophagous butterfly

Ecography ◽  
2005 ◽  
Vol 28 (4) ◽  
pp. 465-474 ◽  
Author(s):  
Jochen Krauss ◽  
Ingolf Steffan-Dewenter ◽  
Christine B. Müller ◽  
Teja Tscharntke
Keyword(s):  
Habitat Quality ◽  
Relative Importance ◽  
Landscape Distribution

Evaluating habitat quality of vertebrates using conservation physiology tools

2010 ◽  
Vol 37 (4) ◽  
pp. 332 ◽  
Author(s):  
Jessica A. Homyack
Keyword(s):  
Population Density ◽  
Habitat Quality ◽  
Stress Hormones ◽  
Habitat Alteration ◽  
Metabolic Rates ◽  
Vital Rates ◽  
Conservation Physiology ◽  
Wildlife Populations ◽  
Field Metabolic Rates

Studies examining how wildlife populations perceive and respond to habitat are common, and many attempt to understand how the quality of available habitats influences population processes such as survival and recruitment. Traditional methods to estimate habitat quality (e.g. population density) have not led to great advancement in our understanding of relationships between habitat and fitness in recent years. Metrics from the discipline of conservation physiology could help researchers to address these difficulties and to meet the challenges that habitat alteration poses to biodiversity. Incorporating physiological metrics that relate energetics or environmental stress to habitats may be powerful measures of habitat quality. By quantifying field metabolic rates, body condition, or concentrations of stress hormones in individual organisms, researchers may identify mechanisms associated with habitat that underlie observed patterns in vital rates (survival and fecundity). Physiological metrics offer useful tools that may identify mechanisms of habitat quality and detect the causes of declines in biodiversity. However, integration among physiologists, ecologists and conservation biologists will require new partnerships and approaches to respond to complex ecological issues.

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