A general framework for jointly modelling thermal and hydric constraints on developing eggs

Abstract

Eggs are a vulnerable stage because they are sensitive to thermal and hydric conditions and yet cannot behaviourally avoid stressful environments. A general mechanistic model of egg development in natural nests requires microclimatic predictions of temperature, humidity, radiation (if above ground) and water potential (if buried in soil) to be integrated with models of heat and water exchange of the egg and the metabolism of the developmental process. Although all the required pieces for such a model now exist, they have not been integrated into a general modelling framework. We developed such an integration using NicheMapR package for mechanistic niche modelling. Specifically, we took an existing general model of egg water exchange and connected it with the microclimate model in NicheMapR to simulate nest thermal and hydric environments, including the effects of soil water potential on liquid and vapour exchange and moisture‐mediated soil thermal conductivity on heat exchange. We then used the Dynamic Energy Budget model within the ectotherm model of NicheMapR as the mechanistic engine for the developmental process, allowing the explicit computation of the dynamics of metabolic heat production and all aspects of mass exchange. We illustrate the modelling framework using existing laboratory and field data on reptiles, insects, and birds. We show that it can capture laboratory observations of water exchange and metabolic heat production and how it can be used to map potential development and water uptake under natural conditions at the continental scale. The modelling framework can be used to interpret laboratory experiments and allows strong inferences to be made about the abiotic constraints on egg development in natural nests under past, present, and future environmental change.

Creating landscape‐appropriate habitat restoration strategies: success of a novel nesting habitat design for imperiled freshwater turtles

“…physiology, performance, morphology, and behavior) of hatchlings incubated in created versus natural nests, as the nest environment impacts many aspects of a turtle's phenotype (Nobel et al 2018). Lastly, application of a mechanistic model of egg development in natural nests permits future studies to elucidate the effects of past and future environmental change on egg development (Kearney & Enriquez‐Urzelai 2023).…”

Effect of moisture, temperature, and maternal influence on the hatching, phenotype, and performance of hawksbill turtles Eretmochelys imbricata

“…During extreme weather events (tropical storms, hurricanes, or seasonal drought conditions), sea turtle embryos will be at even greater risk of mortality (Hewavisenthi & Parmenter 2001, Pike & Stiner 2007, Caut et al 2010, Santidrián Tomillo et al 2012. Therefore, it is necessary to incorporate physiological data related to fitness and survival at various life stages of sea turtles, in order to create more accurate models for longterm conservation efforts (Sanger et al 2018, Kearney & Enriquez-Urzelai 2023. It may be necessary to identify priority areas for conservation that include appropriate temperature and moisture for successful embryonic development and hatchling production, as climate change may reduce the availability of such habitats in the future.…”

Bedrock morphology influences rock barrens turtle nesting habitat energy dynamics

“…Temperature is the most commonly recorded abiotic variable when assessing nesting habitat and the incubation environment (Gedeon et al., 2010 ; Gillooly et al., 2002 ; Maziarz et al., 2017 ). However, energy is another important abiotic factor that directly controls nest temperature yet is understudied within the context of nest habitat conditions, likely due to the complexity in its calculation (Kearney & Enriquez‐Urzelai, 2023 ). The spatial and temporal variability in moisture content, nest material porosity, thermal conductivity, and specific heat capacity all influence the magnitude of the flow of energy.…”

“…Furthermore, biological models for embryo development are often not clearly coupled to these larger‐scale environmental models (e.g., Craig et al., 2020 ; Pomeroy et al., 2007 ). Recent work has shown the potential of coupling abiotic models to biotic models (Kearney & Enriquez‐Urzelai, 2023 ) for understanding climate change impacts on nesting habitat, and so it is important to quantify these abiotic‐biotic linkages and processes to improve our modeling capabilities and ultimately aid in conservation efforts.…”

“…This is especially true when it comes to creating fully integrated ecohydrological models that extend beyond the ground and vegetation into the animal kingdom. As models of reptile egg development become more robust (e.g., Kearney & Enriquez‐Urzelai, 2023 ; Mitchell et al., 2016 ), there will be a need for a more physically accurate representation of the processes that link the surrounding landscape's function, and how it may change under climate and land use changes, to egg development. Ultimately, these complex interactions that drive everything from egg development to the evaporation of the soil moisture in the nest are driven by energy, and so quantifying heat flux and heat storage represents a unique linkage between these different fields.…”