Prey Size Selection of Insular Lizards by Two Sympatric Predatory Bird Species

Padilla, David P.; Nogales, Manuel; Marrero, Patricia

doi:10.3161/068.042.0211

Cited by 34 publications

(17 citation statements)

References 20 publications

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“…Additionally, this risk of predation (and the perception of this risk; Lima ) is likely to increase as the width of the ski runs increases, because lizards will have to travel further to reach refuges. For large‐bodied reptiles (and gravid females), this is particularly important because 1) they may be more susceptible to predation by avian predators that select for larger‐bodied individuals during bird breeding seasons (Padilla, Nogales & Marrero ) and 2) ski resorts encourage larger concentrations of scavenging birds (Storch & Leidenberger ; Jokimaki et al . ) that also may prey on lizards in the area.…”

Section: Discussionmentioning

confidence: 99%

An experiment to test key hypotheses of the drivers of reptile distribution in subalpine ski resorts

Sato

Wood

Schroder

et al. 2013

Journal of Applied Ecology

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Summary Alpine and subalpine ecosystems support many endemic species. These ecosystems are increasingly under threat from human‐induced disturbances such as habitat loss and fragmentation as a consequence of ski resort development and expansion. However, limited peer‐reviewed research has investigated the impacts of ski‐related disturbances on wildlife, particularly on reptiles. To address this knowledge gap, we conducted reptile surveys to determine the patterns of reptile distribution and abundance in Australian ski resorts. Then, using a factorial experimental design, we investigated 1) the influence of temperature and predation in driving observed distributions and 2) how a common ski resort management practice – mowing of modified ski slopes – affected thermal regimes and rates of predation of reptiles on ski runs. We found that the removal of vegetation structural complexity through mowing resulted in significantly higher rates of predation on plasticine models, as well as significantly altered thermal regimes. Crucially, mown ski runs had higher maximum ground temperatures that frequently exceeded the recorded critical maximum body temperatures of the target species of lizards. Thus, mowing has the potential to render these areas unsuitable for thermoregulatory purposes for a large proportion of the potential activity period of reptiles. Together, modifications of the thermal environment and elevated rates of predation appear to explain the avoidance of ski runs by reptiles. To facilitate the persistence of reptiles in disturbed subalpine environments, management plans must focus on implementing strategies that reduce the impact of human activities that alter temperature regimes and predation rates on lizards. Synthesis and Applications. We suggest that the retention of structural complexity on ski runs (e.g. through the cessation of mowing during peak reptile activity periods) and/or revegetation with native plant communities will concurrently provide refuge from predators and buffer against extreme temperatures, making ski runs more hospitable to reptiles. Based on our findings, we emphasize that effective management strategies targeting subalpine biodiversity conservation require an understanding of the drivers that determine species distributions in these landscapes.

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Section: Discussionmentioning

confidence: 99%

An experiment to test key hypotheses of the drivers of reptile distribution in subalpine ski resorts

Sato

Wood

Schroder

et al. 2013

Journal of Applied Ecology

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“…Although predators do not actively select autotomised prey (Downes and Shine 2001; own data) and even avoid them due to their smaller body size (Padilla et al 2007), the risk of predation of tailless lizards may be high (Downes and Shine 2001). Tailless lizards cannot use caudal autotomy during encounters with predators (Kelehear and Webb 2006).…”

Section: Discussionmentioning

confidence: 99%

Locomotor performance of sand lizards (Lacerta agilis): effects of predatory pressure and parasite load

et al. 2013

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Locomotor performance affects foraging efficiency, predator avoidance and consequently fitness. Agility and speed determine the animal's social status and reflect its condition. In this study, we test how predatory pressure and parasite load influences locomotor performance of wild specimens of the sand lizard Lacerta agilis. Animals were chased on a 2-metre racetrack. Lizards with autotomy ran significantly faster than lizards with an intact tail, but there was no significant difference in running speed between individuals with fresh caudal autotomy and regenerated tails. Parasite presence and load, age and sex had no significant effect on speed. Our results indicate that autotomy either alters locomotory behaviour or that individuals with autotomised tails were those that previously survived contact with predators, and therefore represented a subgroup of the fastest individuals. Therefore, in general, predatory pressure but not parasites affected locomotor performance in lizards.

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“…To study prey selection by shrikes along an altitude gradient, we estimated the availability of the main prey (invertebrates and lizards) in Las Cañadas del Teide (high mountain zone) and compared our data with those from Padilla et al (2005Padilla et al ( , 2007 in Malpaís de La Rasca (coastal zone). All the data were collected in the same period using the same sampling methods, to avoid possible biases due to inter-annual fluctuations in prey availability.…”

Section: Methodsmentioning

confidence: 98%

“…The subspecies L. m. koenigi, endemic to the Canary Islands, is one of the few insular shrike populations in the world. It occupies the islands of Lanzarote, Fuerteventura, Gran Canaria and Tenerife (Martín and Lorenzo 2001), but little is known about the biology of the subspecies (Martín and Lorenzo 2001;Grimm 2005;Padilla et al 2005Padilla et al , 2007. The main aim of this study was to describe shrike feeding patterns in the two principal open shrub habitats in the Canary Islands: xeric coastal and high mountain zones.…”

Section: Introductionmentioning

confidence: 98%

Trophic ecology of the Southern Grey Shrike (Lanius meridionalis) in insular environments: the influence of altitude and seasonality

et al. 2009

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The seasonal diet and prey selection of the Southern Grey Shrike (Lanius meridionalis) was studied in two different insular habitats: shrub environments of the Canary Islands in coastal and high mountain zones. We measured, in each season, food availability and prey size in order to determine prey size selection of shrikes along an altitudinal gradient. Moreover, we compared the diet patterns observed with those documented on the continent, to determine if Southern Grey Shrikes in the islands' high mountain zone (which has a continental climate) showed seasonal diet variation similar to those in northern continental areas. We analysed a total of 1,139 shrike pellets collected in 1 year and identified 10,179 prey items. Numerically arthropods (91%), and in terms of biomass lizards (70%) were the main prey consumed by the shrikes. The proportions of the main prey items differed significantly between seasons and habitats. Diet in the coastal areas was less variable than in the high mountain zone. The greater seasonal climatic variation in the high mountain zone was associated with diet patterns similar to those found in some northern continental areas, such as the Iberian Peninsula and southern France. Finally, shrikes selected the largest prey in the high mountain habitat. This suggests that foraging behaviour in this species is related to climatic conditions, as the biggest and most profitable prey were consumed in the most harsh habitats.

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Prey Size Selection of Insular Lizards by Two Sympatric Predatory Bird Species

Cited by 34 publications

References 20 publications

An experiment to test key hypotheses of the drivers of reptile distribution in subalpine ski resorts

An experiment to test key hypotheses of the drivers of reptile distribution in subalpine ski resorts

Locomotor performance of sand lizards (Lacerta agilis): effects of predatory pressure and parasite load

Trophic ecology of the Southern Grey Shrike (Lanius meridionalis) in insular environments: the influence of altitude and seasonality

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