Sand and incubation temperatures in a Sea turtle nesting beach at the Cayos de San Felipe National Park, Pinar del Río, Cuba, during the 2012-2013 season.
Sand temperature at 50 cm depth was measured in three profiles along El Sijú nesting beach, Cayos de San Felipe National Park, Pinar del Río, Cuba during the 2012-2013 nesting season. Sand and incubation temperatures inside and close to nests of Hawksbill (Eret-mochelys imbricata), Loggerhead (Caretta caretta) and Green turtle (Chelonia mydas) were also measured. We compared sand temper-atures among locations with different environmental conditions as well as incubation and sand temperatures during the thermosensitive period. Using regression analysis, we modelled expected nest temperature from sand temperature for assessing the feasibility of using the latter as a proxy for estimating nesting temperature. Temperature at 50 cm depth of all locations during summer were significantly higher than pivotal while in winter it was significantly lower even in sunny areas. Average sand temperature during the peaks of the nesting seasons of the three species were significantly different (F (2,1214) = 942.39, p <0.01), with Green turtle season being the hottest and above pivotal temperature. Mean incubation tem-peratures in nests of C. mydas and C. caretta were higher than those of E. imbricata. Nests incubated during winter (all of E. imbricata) generally became cooler as the winter advanced (F(5,105) = 47.07, p < 0.001), while those incubated during the period of July to October (summer) had mean temperatures above 30.5°C irrespective of the species. We found significant positive differences in the thermo-sensitive period between nest and pivotal temperatures in four (the three species) and negative in two (E. imbricata) out of eight nests. Furthermore, sand temperature during nesting was significantly higher than 29.2°C in four out of the six nests sampled. These re-sults point out a possible skew in hatchlings sex proportion towards females mainly during summer time, when the peak of C. mydas nesting season occurs. The difference between daily average of nest and sand temperatures increased as the incubation progressed. When modelling expected differences and estimating nest temperatures accordingly, we found strong, significant linear relation (r = 0.91, p <0.05) and no significant differences between observed and estimated temperatures (t = 0.96, p = 0.34). Moreover, we were able to estimate nest temperature with good accuracy (R2=0.83, average error=± 0.35ºC), which indicates that sand temperature could be a good proxy for determining average nest temperature during the middle third of the incubation period, which can provide clues about the oc-currence of sex biases.
| Main Authors: | , , , , , , |
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| Format: | Journal Contribution biblioteca |
| Language: | English |
| Published: |
2018
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| Subjects: | Incubation temperature, Sea turtles, Climate change, Temperatura de incubación, Tortugas marinas, Cambio climático, |
| Online Access: | http://hdl.handle.net/1834/14988 |
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