Hot spots and hot moments of diamondback terrapin road‐crossing activity

Crawford, Brian A.; Maerz, John C.; Nibbelink, Nathan P.; Buhlmann, Kurt A.; Norton, Terry M.; Albeke, Shannon E.

doi:10.1111/1365-2664.12195

Cited by 39 publications

(29 citation statements)

References 34 publications

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“…Surveys were carried out between 3 h before and 3 h after the scheduled high tide, coinciding with peaks of nesting activity (Crawford et al . ). We only intercepted females after observing nesting activity and palpated individuals to confirm that all eggs were deposited at that location.…”

Section: Methodsmentioning

confidence: 97%

Estimating the consequences of multiple threats and management strategies for semi‐aquatic turtles

Crawford

Maerz

Nibbelink

et al. 2014

Journal of Applied Ecology

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Summary1. Roads are pervasive fixtures on most landscapes but are typically among many factors contributing to wildlife population declines. Addressing road mortality as part of larger conservation efforts is challenging because it can be difficult to measure per capita mortality from roads and other concurrent threats. 2. We used 4 years of mark-recapture-recovery data for diamondback terrapins Malaclemys terrapin on a causeway in Georgia, USA, to directly estimate threats of adult road mortality and nest predation, contrast the consequences to population growth using stage-based matrix models and make management recommendations to stabilize the population. 3. Mean estimated annual adult road mortality was 11Á1% (range = 4Á4-16Á4%). Estimated annual nest predation was 61Á9%. We estimated that the population was declining (k < 0Á98) in all scenarios where both threats were included. Variation in adult survival was the most influential (highest elasticity) contributor to population growth relative to other demographic rates; however, k would remain below 1 with any nest predation rate exceeding our estimate even if actions to mitigate road mortality were 100% effective. 4. Synthesis and applications. Our study provides some of the first direct estimates of vehicle mortality rates and shows that mortality can remain sufficiently high among years to cause population declines. We also demonstrate that management actions focused on singular threats are inadequate for recovering populations. We conclude that integrated road and predator management is necessary to conserve turtle populations, and we suggest alternative strategies to compensate for some vehicle mortality and nest depredation.

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Section: Methodsmentioning

confidence: 97%

Estimating the consequences of multiple threats and management strategies for semi‐aquatic turtles

Crawford

Maerz

Nibbelink

et al. 2014

Journal of Applied Ecology

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“…In fact, many of the research studies undertaken on road mortality tended to explore the differences between and within species with the intention of informing more targeted mitigation. For instance, studies considered in this review found that a variety of species-associated factors influenced the rate of wildlife-vehicle collisions, such as age (particularly dispersing juveniles; [19][20][21][22][23]), activity patterns (such as nocturnal and migratory activities; [6,7,24,25]), season (primarily breeding season; [12,[26][27][28][29]), gender (such as males ranging further in the breeding season in search a mate; [23,26,[30][31][32]), diet preferences (e.g., one study found that omnivorous mammals and herbivorous birds were most vulnerable; [33]), mobility (including low-flying species; [15,21,34,35]), behavioral responses (e.g., certain species do not respond to oncoming traffic; [15,36]), and home range size (i.e., the larger the home range the higher the probability of crossing a road; [37]). Another study found that species that were more inconspicuous on the roads were more vulnerable to wildlife-vehicle collisions [38].…”

Section: Direct Impacts Of Roads On Wildlifementioning

confidence: 99%

Effects of Road Density and Pattern on the Conservation of Species and Biodiversity

Bennett

2017

Curr Landscape Ecol Rep

137

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The development and presence of roads can reduce landscape permeability, lead to habitat loss, and increase habitat fragmentation. It is these fundamental changes in landscape structure that can have both direct and indirect impacts on the conservation of species and biodiversity. In this review, I examine 215 research studies conducted between 2011 and 2015 that explore the impacts of roads and road networks on a wide range of species. I divided these studies into four main categories: 1) the direct effects of roads on wildlife, 2) the indirect effects of roads on wildlife, 3) the consequences of road networks on wildlife populations, and 4) survey design and mitigation including both innovations and evaluations. I found that the majority of studies (38%) explored the indirect effects of roads on wildlife, including displacement, fitness consequences, and road crossing ability of wildlife. Nevertheless, despite there being a pressing need to understand how existing road networks impact wildlife and how increasing road density may influence local and regional population persistence, only 10% of the studies considered the implications of road networks on wildlife. However, there is an increasing trend towards the development of predictive models that can be used for a better understanding of road network impacts, assess landscape connectivity, and devise mitigation. This review also highlighted the continued need to devise and evaluate mitigation measures so transportation authorities and conservation practitioners may be better equipped to address the ecological implications of roads and proposed road development.

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“…, Crawford et al. ). Within the flourishing subdiscipline of road ecology, however, rarely are both intrinsic and extrinsic factors explicitly and quantitatively assessed within the same system.…”

Section: Introductionmentioning

confidence: 99%

To cross or not to cross: modeling wildlife road crossings as a binary response variable with contextual predictors

2016

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Citation: Siers, S. R., R. N. Reed, and J. A. Savidge. 2016. To cross or not to cross: modeling wildlife road crossings as a binary response variable with contextual predictors. Ecosphere 7(5):e01292. 10. 1002/ecs2.1292 Abstract. Roads are significant barriers to landscape-scale movements of individuals or populations of many wildlife taxa. The decision by an animal near a road to either cross or not cross may be influenced by characteristics of the road, environmental conditions, traits of the individual animal, and other aspects of the context within which the decision is made. We considered such factors in a mixed-effects logistic regression model describing the nightly road crossing probabilities of invasive nocturnal Brown Treesnakes (Boiga irregularis) through short-term radiotracking of 691 snakes within close proximity to 50 road segments across the island of Guam. All measures of road magnitude (traffic volume, gap width, surface type, etc.) were significantly negatively correlated with crossing probabilities. Snake body size was the only intrinsic factor associated with crossing rates, with larger snakes crossing roads more frequently. Humidity was the only environmental variable affecting crossing rate. The distance of the snake from the road at the start of nightly movement trials was the most significant predictor of crossings. The presence of snake traps with live mouse lures during a portion of the trials indicated that localized prey cues reduced the probability of a snake crossing the road away from the traps, suggesting that a snake's decision to cross roads is influenced by local foraging opportunities. Per capita road crossing rates of Brown Treesnakes were very low, and comparisons to historical records suggest that crossing rates have declined in the 60+ yr since introduction to Guam. We report a simplified model that will allow managers to predict road crossing rates based on snake, road, and contextual characteristics. Road crossing simulations based on actual snake size distributions demonstrate that populations with size distributions skewed toward larger snakes will result in a higher number of road crossings. Our method of modeling per capita road crossing probabilities as a binary response variable, influenced by contextual factors, may be useful for describing or predicting road crossings by individuals of other taxa provided that appropriate spatial and temporal resolution can be achieved and that potentially influential covariate data can be obtained.

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Hot spots and hot moments of diamondback terrapin road‐crossing activity

Cited by 39 publications

References 34 publications

Estimating the consequences of multiple threats and management strategies for semi‐aquatic turtles

Estimating the consequences of multiple threats and management strategies for semi‐aquatic turtles

Effects of Road Density and Pattern on the Conservation of Species and Biodiversity

To cross or not to cross: modeling wildlife road crossings as a binary response variable with contextual predictors

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