San José, Costa Rica
San José, Costa Rica

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Rivas M.L.,Endangered Wildlife Trust NGO | Rivas M.L.,University of Granada | Marco A.,CSIC - Doñana Biological Station
Marine Biology | Year: 2016

Leatherback turtles, Dermochelys coriacea, are affected by a range of anthropogenic stressors throughout their range. However, little is known about the species’ responses to natural threats such as dune vegetation, which can have a negative effect on the quality of nesting habitats. In this study, we assessed the potential impact of Ipomoea pes-caprae on the sea-finding abilities of leatherback hatchlings at the Pacuare Nature Reserve on the Caribbean coast of Costa Rica. To analyse their effects on hatchling behaviour, we measured and compared the speed at which hatchlings managed to reach the water at open beach locations and vegetated locations. We recorded nest locations of 1491 nests, which were left in situ, and 784 that were relocated between 2012 and 2014. The majority of in situ nests were located in areas where the vegetation was denser than in open beach. We found that dune vegetation had a negative effect on hatchling speed, which led to an increased exposure time to predators and dehydration and could potentially entail extreme physiological stress affecting hatchling mortality. Thus, the presence of vegetation might negatively influence the suitability of nesting habitats if beach erosion processes increase on nesting grounds in the future. © 2016, Springer-Verlag Berlin Heidelberg.

Rivas M.L.,Endangered Wildlife Trust NGO | Rivas M.L.,University of Granada | Tomillo P.S.,CSIC - Mediterranean Institute for Advanced Studies | Dieguez-Uribeondo J.,Real Jardin Botanico | Marco A.,CSIC - Doñana Biological Station
Marine Ecology Progress Series | Year: 2016

Beaches are constantly being reshaped by storms and tidal action; however, the increased frequency of storms and the sea-level rise due to climate change could cause loss of beaches that are vital breeding habitats for sea turtles. Here we evaluated the effects that erosion/ accretion cycles have on the nesting behavior (nest site selection in relation to the presence of dune scarps) and nesting success (the proportion of nesting activities with oviposition) of leatherback turtles Dermochelys coriacea at Pacuare Nature Reserve, in Caribbean Costa Rica. Dune scarps accounted for over 20% of the beach, creating a barrier which prevented turtles from accessing the upper parts of the beach where nests would be safe from high tides and the storm line. About a quarter of the turtles, 24.1% (n = 20) in 2013 and 18.6% (n = 19) in 2014, did not crawl over scarps when they were present, regardless of their height, and laid their eggs below them. Additionally, during the period 2008 to 2014, the percentage of nests laid in high-risk areas sig - nificantly increased (R2 = 0.91). The end result of the formation of scarps was that nests were laid in areas at risk of being flooded, threatening the survival of those eggs, and therefore the longterm population survival. Since sea levels have been rising significantly in the Caribbean between 1950 and 2010, and projections show a further increase throughout the 21st century, beach erosion may become an important threat not just for leatherbacks, but for many other endangered coastal species. © 2016 Inter-Research.

Rivas M.L.,Endangered Wildlife Trust NGO | Santidrian Tomillo P.,CSIC - Mediterranean Institute for Advanced Studies | Dieguez Uribeondo J.,Real Jardin Botanico | Marco A.,CSIC - Doñana Biological Station
Journal of Experimental Marine Biology and Ecology | Year: 2015

Over the last decades, growing human populations have led to the rising occupation of coastal areas over the globe causing light pollution. For this reason, it is important to assess how this impact threatens endangered wildlife. Leatherback turtles ( Dermochelys coriacea) face many threats of anthropogenic origin including light pollution on nesting beaches. However, little is known about the specific effects. In this study we studied the effect of different light wavelengths (orange, red, blue, green, yellow and white lights) on hatchling orientation under the presence and absence of moonlight by analyzing: (i) the mean angle of orientation, (ii) crawling duration, and (iii) track patterns.Hatchling orientation towards the sea was always better under controlled conditions. In the absence of moonlight, leatherback hatchlings were phototaxically attracted to the experimental focus of light (misoriented) for the colours blue, green, yellow and white lights. Orange and red lights caused a lower misorientation than other colors, and orange lights produced the lowest disrupted orientation (disorientation). On nights when moonlight was present, hatchlings were misorientated under blue and white artificial lights. Crawling duration was low for misoriented hatchlings and high for the disoriented individuals. Our conclusion to this is that hatchlings can detect and be impacted by a wide range of the light spectrum and we recommend avoiding the presence of artificial lights on nesting beaches. Additionally, actions to control and mitigate artificial lighting are especially important during dark nights when moonlight is absent. © 2014 Elsevier B.V.

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