Thermoregulatory strategies of songbird nestlings reveal limited capacity for cooling and high risk of dehydration

Authorea (Authorea), Год журнала: 2023, Номер unknown

Опубликована: Апрель 4, 2023

Developing young are particularly sensitive to environmental challenges, often with life-long consequences, but the risks of climate warming during this period not well understood. To quantify physiological effects increasing temperatures for developing endotherms, we measured metabolic rate, water loss, and heat dissipation behaviours between 25-45°C in nestlings a free-living songbird. The thermoneutral zone ranged from 33.1–42.3°C – higher narrower than adults rate increased sharply above below range. Water loss was constant 33.5°C, which it sharply, when also drooped their wings lose heat. Despite initiating panting (p50) around 40°C, never sufficient dissipate metabolically produced heat, indicating poor cooling capabilities. Our data show that while appear relatively tolerant temperatures, they at high risk dehydration hyperthermia, limited ability mitigate these temperatures.

Язык: Английский

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Moose responses to anthropogenic disturbance across a range of spatial scales: Diet, habitat use, and movement

Опубликована: Янв. 1, 2024

Habitat loss and climate change are two of the leading causes global decline biodiversity. Declines in abundance moose (Alces americanus) British Columbia, Canada, 2000s were hypothesized to result from an interaction between a severe climate-induced insect outbreak resulting increases salvage harvest affected forests. I investigated behavioral distributional responses forest harvesting disturbance across range spatial scales tested use N-mixture models camera trap data estimate population abundance. At fine scale, used microhistological analysis fecal samples assess effects logging on diet moose. In areas with greater intensities harvesting, consumed fewer forbs, shrubs, fir trees, their was more diverse. These dietary consistent Niche Expansion Hypothesis, which predicted that generalist herbivore would eat diversity plants compensate for decreased availability or quality preferred forage. LiDAR GPScollar test hypotheses explained horizontal vertical cover by Risk predation hunting (Direct Mortality Hypothesis) primary factor influenced cover. Moose different structures, ranging open closed, depending threat (predation hunting) response modulated maternal status. coarser assessed suite concerning partial migration, migration habitat used, fitness migration. Wildfire winter driver most migratory experienced less wildfire after leaving range. Migrants displaying specific movement tactics (e.g., distance timing movements) increased probability parturition neonate survival. Migration exposed risk but residents vulnerable health-related mortality. While provided some benefits, it did not fully mitigate amount summer range, particularly seasons. Finally, sensitivity estimates produced parameterized ecological conditions, scale covariates, potential temporally non-independent detections, model choice based parsimony. Nmixture accurate reasonably precise robust formulation, associated criteria define independent detection. However, recommend avoiding measures parsimony selecting generate estimate. total, results my dissertation suggest land management should maintain communities vary structure composition. particular, large-scale can alter moose, expose mortality, and, case wildfire, could lead behaviors populations.

Язык: Английский

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Effects of lead on avian thermoregulation in the heat: An experimental test with pied crows (Corvus albus)

Environmental Toxicology and Pharmacology, Год журнала: 2024, Номер 110, С. 104519 - 104519

Опубликована: Июль 24, 2024

Many of the negative physiological effects lead involve hypothalamus, but possibility that thermoregulation is affected has received little attention. We tested hypothesis exposure reduces avian thermoregulatory performance under hot conditions in pied crows (Corvus albus) experimentally exposed to their diet. Crows our high treatment (blood [Pb] = 87.3 ± 44.7 μg dL

Язык: Английский

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Mind the polar sun: Solar radiations trigger frequent heat stress in breeding king penguins, despite relatively cool air temperatures.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Сен. 13, 2024

Polar and sub-polar animals evolved to thrive in cold climates may thus be particularly vulnerable the rising temperatures associated with climate change. penguins especially due their dual habitat, alternating between foraging waters breeding/moulting on an increasingly warm land. Here, we characterized heat stress occurrence breeding king through behavioural observations subcutaneous body temperature measurements. We show that is frequent (> 20% of at mid-day) sub-Antarctic region, thermoregulatory mechanisms appear insufficient maintain stable sub-cutaneous temperature. Air alone was a poor predictor occurrence, while combination high solar radiations, low wind speed its best predictor. Importantly, reproductive failure occurred days warmer than average, suggesting potential significant sublethal effects being likely affect population dynamics.

Язык: Английский

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Body temperature and thermoregulatory behaviour in the Endangered African Penguin Spheniscus demersus

Bird Conservation International, Год журнала: 2024, Номер 34

Опубликована: Янв. 1, 2024

Summary Heat stress from high temperatures has been recognised as a threat to several bird species and one that is likely increase in severity frequency result of global environmental change. Many seabirds are particularly vulnerable their adaptations forage cold water can make it hard for them resist heat gain while on land. The African Penguin Spheniscus demersus forages cool (10–20°C) but breeds moults land where exceed 30°C. Little known about its thermal physiology when will occur. Here, we provide the first account changes body temperature behaviour Penguins response an experimental ambient 20°C 35°C. Surprisingly, highest observed (39.2°C) was recorded at start study. Presumably, this due transport handling. returned normal (37.3°C) after 3.5 hours maintained normothermia roughly hour. We then onset storage 29°C, whereafter increased steadily rate ca .0.2°C per 1°C temperature. Panting commenced 31.4°C, 37.8°C. In addition panting, penguins changed posture facilitate dissipation by standing, raising heads, extending flippers. Our results corroborate field observations support argument highly near future extreme events become more severe frequent climate also confirm sensitive handling, which elicits hyperthermic response. Given general sensitivity disturbance, conservation perspective, advise cautionary measures be implemented colonies during critical life-history stages.

Язык: Английский

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