An official website of the United States government
Abstract Climate change is intensifying extreme weather events, including marine heatwaves, which are prolonged periods of anomalously high sea surface temperature that pose a novel threat to aquatic animals. Tropical animals may be especially vulnerable to marine heatwaves because they are adapted to a narrow temperature range. If these animals cannot acclimate to marine heatwaves, the extreme heat could impair their behavior and fitness. Here, we investigated how marine heatwave conditions affected the performance and thermal tolerance of a tropical predatory fish, arceye hawkfish (Paracirrhites arcatus), across two seasons in Moorea, French Polynesia. We found that the fish’s daily activities, including recovery from burst swimming and digestion, were more energetically costly in fish exposed to marine heatwave conditions across both seasons, while their aerobic capacity remained the same. Given their constrained energy budget, these rising costs associated with warming may impact how hawkfish prioritize activities. Additionally, hawkfish that were exposed to hotter temperatures exhibited cardiac plasticity by increasing their maximum heart rate but were still operating within a few degrees of their thermal limits. With more frequent and intense heatwaves, hawkfish, and other tropical fishes must rapidly acclimate, or they may suffer physiological consequences that alter their role in the ecosystem.
more »
« less
Diet effects on ectotherm thermal performance
ABSTRACT The environment is changing rapidly, and considerable research is aimed at understanding the capacity of organisms to respond. Changes in environmental temperature are particularly concerning as most animals are ectothermic, with temperature considered a key factor governing their ecology, biogeography, behaviour and physiology. The ability of ectotherms to persist in an increasingly warm, variable, and unpredictable future will depend on their nutritional status. Nutritional resources (e.g. food availability, quality, options) vary across space and time and in response to environmental change, but animals also have the capacity to alter how much they eat and what they eat, which may help them improve their performance under climate change. In this review, we discuss the state of knowledge in the intersection between animal nutrition and temperature. We take a mechanistic approach to describe nutrients (i.e. broad macronutrients, specific lipids, and micronutrients) that may impact thermal performance and discuss what is currently known about their role in ectotherm thermal plasticity, thermoregulatory behaviour, diet preference, and thermal tolerance. We finish by describing how this topic can inform ectotherm biogeography, behaviour, and aquaculture research.
more »
« less
- Award ID(s):
- 2305704
- PAR ID:
- 10524136
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Biological Reviews
- Volume:
- 99
- Issue:
- 4
- ISSN:
- 1464-7931
- Page Range / eLocation ID:
- 1537 to 1555
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Climate change has the potential to disrupt species interactions across global ecosystems. Ectotherm–endotherm interactions may be especially prone to this risk due to the possible mismatch between the species in physiological response and performance. However, few studies have examined how changing temperatures might differentially impact species' niches or available suitable habitat when they have very different modes of thermoregulation. An ideal system for studying this interaction is the predator–prey system. In this study, we used ecological niche modeling to characterize the niche overlap and examine biogeography in past and future climate conditions of prairie rattlesnakes (Crotalus viridis) and Ord's kangaroo rats (Dipodomys ordii), an endotherm–ectotherm pair typifying a predator–prey species interaction. Our models show a high niche overlap between these two species (D = 0.863 andI = 0.979) and further affirm similar paleoecological distributions during the last glacial maximum (LGM) and mid‐Holocene (MH). Under future climate change scenarios, we found that prairie rattlesnakes may experience a reduction in overall suitable habitat (RCP 2.6 = −1.82%, 4.5 = −4.62%, 8.5 = −7.34%), whereas Ord's kangaroo rats may experience an increase (RCP 2.6 = 9.8%, 4.5 = 11.71%, 8.5 = 8.37%). We found a shared trend of stable suitable habitat at northern latitudes but reduced suitability in southern portions of the range, and we propose future monitoring and conservation be focused on those areas. Overall, we demonstrate a biogeographic example of how interacting ectotherm–endotherm species may have mismatched responses under climate change scenarios and the models presented here can serve as a starting point for further investigation into the biogeography of these systems.more » « less
-
Abstract Climate warming is predicted to increase mean temperatures and thermal extremes on a global scale. Because their body temperature depends on the environmental temperature, ectotherms bear the full brunt of climate warming. Predicting the impact of climate warming on ectotherm diversity and distributions requires a framework that can translate temperature effects on ectotherm life‐history traits into population‐ and community‐level outcomes. Here we present a mechanistic theoretical framework that can predict the fundamental thermal niche and climate envelope of ectotherm species based on how temperature affects the underlying life‐history traits. The advantage of this framework is twofold. First, it can translate temperature effects on the phenotypic traits of individual organisms to population‐level patterns observed in nature. Second, it can predict thermal niches and climate envelopes based solely on trait response data and, hence, completely independently of any population‐level information. We find that the temperature at which the intrinsic growth rate is maximized exceeds the temperature at which abundance is maximized under density‐dependent growth. As a result, the temperature at which a species will increase the fastest when rare is lower than the temperature at which it will recover from a perturbation the fastest when abundant. We test model predictions using data from a naturalized–invasive interaction to identify the temperatures at which the invasive can most easily invade the naturalized's habitat and the naturalized is most likely to resist the invasive. The framework is sufficiently mechanistic to yield reliable predictions for individual species and sufficiently broad to apply across a range of ectothermic taxa. This ability to predict the thermal niche before a species encounters a new thermal environment is essential to mitigating some of the major effects of climate change on ectotherm populations around the globe.more » « less
-
ABSTRACT Thermal acclimation is a key process enabling ectotherms to cope with temperature change. To undergo a successful acclimation response, ectotherms require energy and nutritional building blocks obtained from their diet. However, diet is often overlooked as a factor that can alter acclimation responses. Using a temperate omnivorous fish, opaleye (Girella nigricans), as a model system, we tested the hypotheses that (1) diet can impact the magnitude of thermal acclimation responses and (2) traits vary in their sensitivity to both temperature acclimation and diet. We fed opaleye a simple omnivorous diet (ad libitum Artemia sp. and Ulva sp.) or a carnivorous diet (ad libitum Artemia sp.) at two ecologically relevant temperatures (12 and 20°C) and measured a suite of whole-animal (growth, sprint speed, metabolism), organ (cardiac thermal tolerance) and cellular-level traits (oxidative stress, glycolytic capacity). When opaleye were offered two diet options compared with one, they had reduced cardiovascular thermal performance and higher standard metabolic rate under conditions representative of the maximal seasonal temperature the population experiences (20°C). Further, sprint speed and absolute aerobic scope were insensitive to diet and temperature, while growth was highly sensitive to temperature but not diet, and standard metabolic rate and maximum heart rate were sensitive to both diet and temperature. Our results reveal that diet influences thermal performance in trait-specific ways, which could create diet trade-offs for generalist ectotherms living in thermally variable environments. Ectotherms that alter their diet may be able to regulate their performance at different environmental temperatures.more » « less
-
Abstract The production and consumption of food is one of the main drivers of environmental change globally. Meanwhile, many populations remain malnourished due to insufficient or unhealthy diets. Increasingly, dietary shifts are proposed as a means to address both environmental and health concerns. We have a limited understanding of how dietary shifts could alter where food is produced and consumed and how these changes would affect the distribution of environmental pressures both globally and across different groups of people. Here we combine new food flow data linking producing to consuming country with environmental pressures to estimate how a global shift to each of four diets (Indian, EAT-Lancet, Mediterranean, and mean Food Based Dietary Guidelines (FBDGs)) could affect environmental pressures at the global, country income group, and country level. Globally, cumulative pressures decrease under the Indian, EAT-Lancet, and Mediterranean scenarios and increase under FBDGs. On average, low income countries increase their cumulative consumption and production pressures while high income countries decrease their consumption pressures, and typically decrease their production pressures. Increases in low income countries are likely due to the nutritional inadequacy of current diets and the corresponding increases in consumption quantities with a shift to our diet scenarios. Despite these increases, we believe that three out four of our simulated dietary shifts can be seen as a net benefit by decreasing global pressures while low income countries increase pressures to adequately feed their populations. Additionally, considering principles of fairness applied, some nations are more responsible for causing historical environmental pressures and should shoulder more of the change. To facilitate more equitable shifts in global diets, resources, capacity, and knowledge sharing of sustainable agricultural practices are critical to minimize the increases in pressures that low income countries would incur to adequately feed their populations.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/brv.13081
