Regional warming and the thermal regimes of American crocodile nests in the Tempisque Basin, Costa Rica

Murray, Christopher M.; Easter, Michael; Padilla, Sergio E.; Marín, Mahmood Sasa; Guyer, Craig

doi:10.1016/j.jtherbio.2016.06.004

Cited by 17 publications

(11 citation statements)

References 33 publications

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“…For example, some organisms differentiate based on environmental cues, such as temperature 1 . This can occur when seasonal differences in development between the sexes optimizes adult fecundity, in some cases, allowing females to grow larger than males 2 – 4 . In stable populations, these skewed sex ratios typically average to a 1:1 ratio over time 5 , 6 , however little is known about how organisms with this sensitive physiology may be influenced by anthropogenic stressors.…”

Section: Introductionmentioning

confidence: 99%

Combined effects of increased temperature and endocrine disrupting pollutants on sex determination, survival, and development across generations

DeCourten

Brander

2017

Sci Rep

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Understanding the combined effects of anthropogenic impacts such as climate change and pollution on aquatic ecosystems is critical. However, little is known about how predicted temperature increases may affect the activity of endocrine disrupting compounds (EDCs), particularly in species with plasticity in sex determination. We investigated the effects of a concomitant increase in temperature and exposure to estrogenic EDCs on reproduction and development in an estuarine model organism (Menidia beryllina) across multiple generations. Parents (P) were exposed to environmental levels of the estrogenic insecticide bifenthrin or ethinylestradiol (EE2) at 22 °C and 28 °C for 14 days prior to the initiation of spawning trials. Embryos in the F1 generation were exposed to EDCs until 21 days post hatch (dph), reared to adulthood in clean water at elevated temperatures, and spawned. F1 sex ratios were significantly influenced by elevated temperature and EDCs, potentially altering adaptive development. We also observed fewer viable offspring and increased developmental deformities in the F1 and F2 generations, with a greater impact on F2 juveniles. These findings enhance our understanding of responses to EDCs in the context of climate change and may demonstrate heritable effects. Our study represents the first multigenerational assessment of elevated temperatures in combination with environmentally relevant concentrations of commonly detected endocrine disruptors in a model vertebrate species.

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Section: Introductionmentioning

confidence: 99%

Combined effects of increased temperature and endocrine disrupting pollutants on sex determination, survival, and development across generations

DeCourten

Brander

2017

Sci Rep

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“…But each egg experiences a different temperature fluctuation due to its location inside the nest and the depth of nest itself. Eggs in the top layer of the nest usually experience highest fluctuations being in closest proximity to external temperature whereas eggs in lower layer experience low fluctuations (Murray et al., 2016).…”

Section: Discussionmentioning

confidence: 99%

Sand addition promotes gharial nesting in a regulated river‐reservoir habitat

Vashistha

Lang

Dhakate

et al. 2021

Ecol Sol and Evidence

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1. The gharial (Gavialis gangeticus) is a critically endangered, long-snouted crocodilian, endemic to the Indian sub-continent. Today, the species' distribution and numbers have reduced by more than 95% in all the large rivers where it was formerly abundant. Living upstream in a reservoir dammed in 1976, the Katerniaghat gharial population has continued to nest along the Girwa River, subject to seasonal flooding in recent decades. In 2010, a natural flood upstream in Nepal resulted in a permanent reduction in the mainstream river flow. As a consequence of reduced flow, the formerly open sand banks and mid-river islands have converted gradually to riverbanks with woody vegetation. Coincident with the increased vegetation growth, gharial nesting sites and nest numbers declined by more than 40% by 2018.2. In an attempt to reverse the observed decline in nesting, we intervened with vegetation removal (VR) in 2019 and sand addition (SA) in 2020, to augment available nesting opportunities at previous and potential nesting locations.3. The number of nests increased with SA (n = 36 in 2020) but decreased with VR (n = 19 in 2019), relative to the prior year without intervention (n = 25 in 2018). Furthermore, hatching success increased significantly to 93% with SA, compared to 63% in VR. Creating an artificial sand bank required approximately one-third work hours and cost much less than removing vegetation. Substrate temperatures in and around nests approximated the viable incubation range (29-33.5 • C) when vegetation is absent, but were lower in sites covered with woody vegetation and/or dense, high grass.4. Our study indicates that gharial will respond favourably to newly created sand banks that provide open, sandy riverside nesting areas, in contrast to cut-over sites with dense vegetation removed.5. Finally, we note that this strategy of augmenting nesting sites is only an interim attempt to solve the 'nesting site' dilemma for the river-adapted gharial. Landscapelevel solutions related to resumption of seasonal flooding, and particularly naturalThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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“…Previous studies have successfully deployed similar data loggers with built in sensors and data storage (López-Luna et al, 2015;González-Desales et al, 2016;Murray et al, 2016). However, these projects did not experience the same apparent level of instrument loss (Charruau, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…It is a federally threatened species that may be affected by ecosystem restoration projects, particularly those related to the greater Everglades and Florida Bay (Mazzotti et al, 2007a;Mazzotti et al, 2009). As documented across other crocodylian species (Thorbjarnarson, 1996;Cañas & Anderson, 2002;Piña, Merchant & Verdade, 2015), environmental changes within American crocodile nests can significantly affect the health and survival of the developing young (Lutz & Dunbar-Cooper, 1984;Mazzotti et al, 1986;Mazzotti, Kushlan & Dunbar-Cooper, 1988;Mazzotti, 1989;Charruau, 2012;Charruau, Hénaut & Álvarez Legorreta, 2013;Murray et al, 2016). Crocodylus acutus exhibits temperature-dependent sex determination (Murray et al, 2016;Charruau, Cantón & De la Cruz, 2017), and developing embryos are vulnerable to both flooding and desiccation (Mazzotti, Kushlan & Dunbar-Cooper, 1988;Kushlan & Mazzotti, 1989;Charruau, Thorbjarnarson & Hénaut, 2010).…”

Section: Introductionmentioning

confidence: 99%

Crocodylus acutus (American crocodile) bite marks on a nest data logger

Drumheller

Nestler

Farris

et al. 2020

PeerJ

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Several data loggers deployed to monitor temperature and humidity of Crocodylus acutus (American crocodile) nests in South Florida could not be located after hatching. One badly damaged data logger was retrieved, providing insight into the possible fate of the others. Using a taphonomic approach, we identified numerous indentations, consistent with crocodylian bite marks, and inconsistent with potential mammalian or squamate bites. It seems most likely that the data logger was damaged by the nesting C. acutus rather than during attempted nest predation. Estimated bite forces for reproductive age, female C. acutus exceed the predicted material properties of the data logger’s housing, suggesting that the bites were exploratory in nature. We suggest that data loggers be removed prior to hatching or permit remote data storage.

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Regional warming and the thermal regimes of American crocodile nests in the Tempisque Basin, Costa Rica

Cited by 17 publications

References 33 publications

Combined effects of increased temperature and endocrine disrupting pollutants on sex determination, survival, and development across generations

Combined effects of increased temperature and endocrine disrupting pollutants on sex determination, survival, and development across generations

Sand addition promotes gharial nesting in a regulated river‐reservoir habitat

Crocodylus acutus (American crocodile) bite marks on a nest data logger

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