How will changes in local climate affect hawksbill hatchling production in Brazil?

Abstract

23Local climatic conditions can influence sea turtle embryonic development and hatchling 24 viability. Therefore, it is crucial to understand these influences as well as potential ramifications 25 to population stability under future climate change. Here, we examined the influences of five 26 climatic variables (air temperature, accumulated and average precipitation, humidity, solar 27 radiation, and wind speed) at different temporal scales on hawksbill sea turtle (Eretmochelys 28 imbricata) hatchling production at ten nesting beaches within two regions of Brazil (five nesting 29 beaches in Rio Grande do Norte and five in Bahia). Air temperature and accumulated 30 precipitation were the main climatic drivers of hawksbill hatching success across Brazil and in 31 Rio Grande do Norte, while air temperature and average precipitation were the main climatic 32 drivers of hatching success at Bahia. Solar radiation was the main climatic driver of emergence 33 rate at both regions. Conservative and extreme climate scenarios show air temperatures are 34 projected to increase, while precipitation projections vary between scenarios and regions 35 throughout the 21 st century. We predicted hatching success of undisturbed nests (no recorded 36 depredation or storm-related impacts) will decrease in Brazil by 2100. This study shows the 37 determining effects of different climate variables and their combinations on an important and 38 critically endangered marine species. 39 Introduction 40Changes in climate have already impacted the physiology, phenology, behavior, 41 distribution, and reproduction of many species [1][2][3]. Species that are expected to be most 42 vulnerable are those that are heavily reliant on environmental temperature for their life history 43 traits and/or those that exhibit temperature dependent sex determination (TSD) [4][5][6][7]. This is the 3 44 case for sea turtles, as their life history, physiology, and behavioral traits are heavily influenced 45 by environmental temperature, particularly while their eggs are incubating [8-10]. Successful 46 incubation of sea turtle eggs typically occurs within a specific thermal range of 25°C -35°C [8], 47 with reduced embryonic development and altered hatchling physiology being observed at 48 extreme temperatures [11-13]. Moisture content also influences embryos with reduced 49 development being observed when conditions are too moist/dry [14-16]. Further, the sex of sea 50 turtle hatchlings is temperature dependent, with warmer temperatures producing a higher 51proportion of female hatchlings [17, 18]. Thus, any changes to the nesting environment can alter 52 hatchling phenotype and survival, impacting sea turtle populations [19][20][21]. 53The impacts of climate change on hatchling production have already been observed through 54 skewed sex ratios, malformations in hatchlings, lowered hatching success, and altered hatchling 55 behavior [13, 22, 23]. Therefore, concern exists over the potential impacts of climate change on 56 hatchling production and populatio...

Adaptation of sea turtles to climate warming: Will phenological responses be sufficient to counteract changes in reproductive output?

“…It is also important to consider that our study focuses on temperature‐driven hatching success whereas other environmental factors, such as precipitation and moisture have also been found to influence hatching success (Montero, Marcovaldi, et al., 2018; Rafferty et al., 2017). For instance, embryos can die from suffocation if the nest is flooded from heavy rainfall for an extended period or from desiccation in the opposite case.…”

“…to influence hatching success (Montero, Marcovaldi, et al, 2018;Rafferty et al, 2017). For instance, embryos can die from suffocation if the nest is flooded from heavy rainfall for an extended period or from desiccation in the opposite case.…”