Does waterproofing Thermochron iButton dataloggers influence temperature readings?

How turtles keep their cool: Seasonal and diel basking patterns in a tropical turtle

Behavioural thermoregulation by ectotherms is an important mechanism for maintaining body temperatures to optimise physiological performance. Experimental studies suggest that nocturnal basking by Krefft's river turtles (Emydura macquarii krefftii) in the tropics may allow them to avoid high water temperatures, however, this hypothesis has yet to be tested in the field. In this study, we examined the influence of environmental temperature on seasonal and diel patterns of basking in E. m. krefftii in tropical north Queensland, Australia. Wildlife cameras were used to document turtle basking events for seven consecutive days and nights for each month over a year (April 2020-March 2021). Air and water temperatures were recorded simultaneously using temperature loggers. We used a negative binomial mixed effects model to compare mean basking durations (min) occurring among four environmental temperature categories based on population thermal preference (26 °C): 1) air temperature above and water temperature below preferred temperature; 2) air temperature below and water temperature above preferred temperature; 3) air and water temperatures both above preferred temperature; and 4) air and water temperatures both below preferred temperature. Basking behaviour was influenced significantly by the relationship between air and water temperature. During the day, turtles spent significantly less time basking when both air and water temperatures were above their preferred temperatures. Conversely, at night, turtles spent significantly more time basking when water temperatures were warm and air temperatures were cool relative to their preferred temperature. This study adds to the growing body of work indicating pronounced heat avoidance as a thermoregulatory strategy among tropical reptile populations.

Climate warming drives a temperate-zone lizard to its upper thermal limits, restricting activity, and increasing energetic costs

Lizards are considered vulnerable to climate change because many operate near their thermal maxima. Exposure to higher temperatures could reduce activity of these animals by forcing them to shelter in thermal refugia for prolonged periods to avoid exceeding lethal limits. While rising temperatures should reduce activity in tropical species, the situation is less clear for temperate-zone species where activity can be constrained by both low and high temperatures. Here, we measure the effects of natural variation in environmental temperatures on activity in a temperate grassland lizard and show that it is operating near its upper thermal limit in summer even when sheltering in thermal refuges. As air temperatures increased above 32 °C, lizard activity declined markedly as individuals sought refuge in cool microhabitats while still incurring substantial metabolic costs. We estimate that warming over the last two decades has required these lizards to increase their energy intake up to 40% to offset metabolic losses caused by rising temperatures. Our results show that recent increases in temperature are sufficient to exceed the thermal and metabolic limits of temperate-zone grassland lizards. Extended periods of high temperatures could place natural populations of ectotherms under significantly increased environmental stress and contribute to population declines and extinction.

High resolution thermal remote sensing and the limits of species' tolerance

Extinction risks for many insect species, particularly across very broad spatial extents, have been linked to the growing frequency and severity of temperatures that exceed the boundaries of their realized niches. Measurement and mitigation of such impacts is hindered by the availability of high-resolution measurements of species-specific severity of extreme weather, especially temperature. While techniques enabling interpolation of broad-scale remote sensing metrics are vital for such efforts, direct remote sensing measurements of thermal conditions could improve habitat management by providing detailed insights that interpolative approaches cannot. Advances in unmanned aerial vehicle (UAV) technology have created opportunities to better evaluate the role of microclimates in local species extinctions. Here, we develop a method to create high-resolution maps of microclimates using UAV and thermal imaging technology that use species' realized niche boundaries to assess potential effects of severity of extreme temperatures. We generated air temperature maps (5 cm resolution) and canopy height maps (1 cm resolution) for 15 sites in a rare alvar ecosystem in eastern Ontario. We validated these remote sensing observations against independent, in situ temperature observations using iButtons. Temperature observations were accurate and related to physical heterogeneity in alvar habitats. We converted temperature measures into estimates of proximity of thermal niche boundaries for three butterfly species found during field surveys. This is the first time that this method has been applied to high resolution remote sensing observations and offers potential to assess the availability and adequacy of microclimates within habitats at resolutions relevant for conservation management.

Internal Temperatures of Packaging for Overnight Cross-country Shipping of Zebrafish (Danio Rerio)

As the use of zebrafish (Danio rerio) as a research model continues to rise, so too will the shipping and sharing of zebrafish strains across collaborating institutions. If done incorrectly, shipping can result in significant mortality, welfare concerns, and loss of valuable resources for researchers and research institutions. Here we introduce a novel method to track temperatures of zebrafish containers during shipping and show that internal packaging temperatures are directly affected by the external temperatures. We used temperature logging Thermochron iButtons to track the temperatures of 2 packages containing adult zebrafish that were shipped overnight from Dallas, TX to Columbus, OH during winter following recommended fish shipping guidelines. We found that the external packaging of both boxes of fish were exposed to temperatures that had previously been shown to be lethal to zebrafish. However, internal temperatures and, more specifically, water temperature, stayed within 24.0 to 26.5^°C during shipment, resulting in 100% survival of adult zebrafish. This novel method of tracking packaging temperatures of live fish during shipping can help to inform fish health status on arrival.

Microhabitat Associations for the Threatened Cheat Mountain Salamander in Relation to Early-stage Red Spruce Restoration Areas

The Central Appalachian Spruce Restoration Initiative was formed to promote restoration of red spruce Picea rubens forests in Central Appalachia. One goal of the initiative is to increase availability and enhance quality of habitat for wildlife, including the threatened Cheat Mountain salamander Plethodon nettingi. The purpose of this research was to compare microhabitat characteristics between an occupied Cheat Mountain salamander site and early-stage spruce restoration sites, and between four occupied sites and proximal non-detection sites. We found that soil pH was higher and soil moisture was lower at spruce restoration sites compared to the occupied site, and that light intensity, sub-canopy air temperature, and ground-level air temperature were higher in spruce restoration prescriptions with reduced canopy cover. We found that soil moisture was higher at occupied sites compared to proximal non-detection sites, but soil pH was not significantly different. Our study suggests that Cheat Mountain salamanders are associated with low soil pH and high soil moisture, and thus spruce restoration could enhance habitat quality for this species in the long-term.

Facing up to climate change: Community composition varies with aspect and surface temperature in the rocky intertidal

Marine rocky intertidal organisms are amongst those most affected by climate change with regional distributional changes observed for many species. Although often ascribed to increased sea surface temperatures, precise assessment of the local habitat conditions underpinning observed and predicted changes in community assembly is lacking. Here we examine how aspect (i.e. north-south orientation) affects intertidal community composition and how rock surface temperatures and stress responses of two dominant grazer species (Patella spp.) elucidate emergent differences. We quantified year-round temperature variation and surveyed intertidal community composition on paired natural rock gullies with Equator- (EF) and Pole-facing (PF) surfaces. We also investigated variation in limpet (Patella spp.) reproductive phenology and osmotic stress. Average annual temperatures were 0.8 °C (1.6 °C at low tide) higher, with six-fold more frequent extremes (i.e. > 30 °C) on EF than PF surfaces. Intertidal community composition varied with aspect across trophic levels with greater overall species richness, abundance of primary producers and grazers on PF-surfaces, and greater barnacle abundance on EF-surfaces. Although species richness of organisms from different biogeographical origins ('Boreal' or 'Lusitanian') did not vary, the Lusitanian limpet Patella depressa exhibited earlier reproductive development on EF-surfaces and both limpet species exhibited greater thermal stress on EF-surfaces. We argue that our study system provides a good model for understanding how temperature variation at local scales can affect community composition, as well as ecophysiological and ecological responses to climate change and so better inform and predict regional range shifts over coming decades.

Automated Monitoring of Cattle Heat Stress and Its Mitigation

Climate change related global warming is likely to continue, despite all mitigation measures taken by humans, due to the lag effect of long-term anthropogenic activities. Warming of the atmosphere can impact worldwide cattle production directly by compromising health, welfare and productivity, and indirectly by reducing the quality and quantity of animal feed. Under warm thermal conditions, cattle adjust their physiological and behavioural responses as an integral part of thermoregulation to maintain internal body temperature within a safe range. However, a greater intensity and duration of heat exposure can exceed thermoregulatory capacity leading to an increase in internal body temperature beyond the normal limit that ultimately evokes different animal responses to heat. In cattle, response to heat stress can be visually observed as elevated respiration rate or panting, but continuous visual monitoring is labour intensive, time consuming and subjective. Therefore, different weather-based indices have been developed such as the temperature humidity index (THI) and heat load index (HLI) which are commonly used weather-based indices for monitoring cattle heat stress at commercial level. However, the thermal comfort level of cattle based on weather-based indices has limited use at a microclimatic and individual animal level. Varying sensor-based approaches have shown promise to shift the focus of heat stress management to the individual level. Monitoring individual animal response and mitigation strategies for isolated heat-susceptible cattle could save on heat management costs whilst improving animal welfare and productivity. Here we review the technologies that enable automatic, continuous, and real-time cattle heat stress monitoring and mitigation under commercial conditions. Future platforms for autonomous monitoring and mitigation of heat stress in cattle are likely to be based on minimally-invasive smart technologies either singly, or in an integrated system, enabling real-time solutions to animal responses under various production systems and environmental conditions.

TEMPERATURE AS A DRIVER OF THE PATHOGENICITY AND VIRULENCE OF AMPHIBIAN CHYTRID FUNGUS BATRACHOCHYTRIUM DENDROBATIDIS: A SYSTEMATIC REVIEW

Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is a leading cause of global amphibian declines. Severe infections with Bd can lead to cardiac arrest, and mass deaths during epidemics have been reported. Temperature, pH, salinity, and moisture are important determinants of the survival, growth, reproduction, and pathogenicity of Bd, as well as its effect on amphibian populations. Here, we synthesize current knowledge on the role of temperature as a driver of the pathogenicity and virulence of Bd to better understand the effects of temperature on amphibian defense mechanisms against infection. This review advises on research direction and management approaches to benefit amphibian populations affected by Bd. We conclude by offering guidelines for four levels of temperature monitoring in amphibian field studies to improve consistency between studies: regional climate, habitat, microhabitat, and amphibian host.

sUAS Remote Sensing to Evaluate Geothermal Seep Interactions with the Yellowstone River, Montana, USA

Small unmanned aerial systems (sUAS) are becoming increasingly popular due to their affordability and logistical ease for repeated surveys. While sUAS-based remote sensing has many applications in water resource management, their applicability and limitations in fluvial settings is not well defined. This study uses a combined thermal-optic sUAS to monitor the seasonal geothermal influence of a 1-km-long reach of the Yellowstone River, paired with in-situ streambed temperature profiles to evaluate geothermal seep interactions with Yellowstone River in Montana, USA. Accurate river water surface elevation along the shoreline was estimated using structure from motion (SfM) photogrammetry digital surface models (DSMs); however, water surface elevations were unreliable in the main river channel. Water temperature in thermal infrared (TIR) orthomosaics was accurate in temperature ranges of tens of degrees (>≈30 °C), but not as accurate in temperature ranges of several degrees (>≈15 °C) as compared to in-situ water temperature measurements. This allowed for identification of geothermal features but limited the ability to identify small-scale temperature changes due to river features, such as pools and riffles. The study concludes that rivers with an average width greater than or equal to 123% of the ground area covered by a TIR image will be difficult to study using structure from motion photogrammetry, given Federal Aviation Administration (FAA) altitude restrictions and sensor field of view. This study demonstrates the potential of combined thermal-optic sUAS systems to collect data over large river systems, and when combined with in-situ measurements, can further increase the sUAS utility in identifying river characteristics.

Connectivity over a disease risk gradient enables recovery of rainforest frogs

Chytridiomycosis has been a key driver of global frog declines and extinctions, particularly for high-altitude populations across Australia and the Americas. While recent evidence shows some species are recovering, the extent of such recoveries and the mechanisms underpinning them remain poorly resolved. We surveyed the historical latitudinal and elevational range of four Australian rainforest frogs that disappeared from upland sites between 1989 and 1994 to establish their contemporary distribution and elevational limits, and investigate factors affecting population recovery. Five rainforest streams were surveyed from mountain-base to summit (30 sites in total), with swabs collected from the target species (Litoria dayi, L. nannotis, L. rheocola, and L. serrata) to determine their infection status, and data loggers deployed to measure microclimatic variation across the elevational gradient. Infection probability increased with elevation and canopy cover as it was tightly and inversely correlated with stream-side air temperature. Occupancy patterns suggest varying responses to this disease threat gradient. Two species, L. rheocola and L. serrata, were found over their full historical elevational range (≥1,000 m above sea level [asl]), while L. dayi was not detected above 400 m (formerly known up to 900 m asl) and L. nannotis was not detected above 800 m (formerly known up to 1,200 m asl). Site occupancy probability was negatively related to predicted infection prevalence for L. dayi, L. nannotis, and L. rheocola, but not L. serrata, which appears to now tolerate high fungal burdens. This study highlights the importance of environmental refuges and connectivity across disease risk gradients for the persistence and natural recovery of frogs susceptible to chytridiomycosis. Likewise, in documenting both interspecific variation in recovery rates and intraspecific differences between sites, this study suggests interactions between disease threats and host selection exist that could be manipulated. For example, translocations may be warranted where connectivity is poor or the increase in disease risk is too steep to allow recolonization, combined with assisted selection or use of founders from populations that have already undergone natural selection.

Feeding alters the preferred body temperature of Cururu toads, Rhinella diptycha (Anura, Bufonidae)

Ectothermic organisms depend primarily on external heat sources and behavioural adjustments to regulate body temperature. Under controlled conditions, in a thermal gradient, body temperature often clusters around a more or less defined range of preferred body temperatures (T_pref). However, T_pref may be modified in response to environmental parameters and/or physiological state. For example, meal ingestion is sometimes followed by a post-prandial thermophilic response leading to a transient increment in T_pref. Although thought to optimize digestive processes, its occurrence, magnitude, and possible determinants remains scarcely documented for anuran amphibians. Herein, we investigated whether the Cururu toad, Rhinella diptycha, exhibits a post-prandial thermophilic response by monitoring the body temperature of fasting and fed toads while they were maintained in a thermal gradient. We found that the toads' T_pref increased by about 13% from day 2 to 4 after feeding, in comparison with the T_pref recorded under fasting. Also, fed animals exhibited a broader range for T_pref at days 2 and 3 post-prandial, which reflects a greater level of locomotor activity compared to fasting individuals. We conclude that R. diptycha is capable to exhibit a post-prandial thermophilic response under the controlled conditions of a thermal gradient. Although this thermoregulatory adjustment is thought to optimize meal digestion yielding important energetic and ecological benefits, its occurrence in anuran amphibians in nature remains uncertain.

The search for an elusive worm in the tropics, the past as a key to the present, and reverse uniformitarianism

The distribution of trace-making organisms in coastal settings is largely controlled by changes in physicochemical parameters, which in turn are a response to different climatic and oceanographic conditions. The trace fossil Macaronichnus and its modern producers are typical of high-energy, siliciclastic foreshore sands in intermediate- to high-latitude settings characterized by cold-water conditions. However, it has been found in Miocene Caribbean deposits of Venezuela, prompting the hypothesis that upwelling of cold, nutrient-rich waters rather than latitude was the main control of its distribution. To test this hypothesis that was solely based on the fossil record, several trenches and sediment peels were made in two high-energy sand beaches having different oceanographic conditions along the Pacific and Caribbean coasts of the Central American Isthmus. As predicted, the burrows were found only in the highly productive waters of the Pacific coast of Costa Rica in connection with upwelling, while they were absent from the warm, oligotrophic waters of the Caribbean coast of Panama. This finding demonstrates that sometimes the past may be a key to the present, providing one of the few documented examples of reverse uniformitarianism.

Reduced thermal variability in cities and its impact on honey bee thermal tolerance

Urbanization is one of the most significant land cover transformations, and while climate alteration is one of its most cited ecological consequences we have very limited knowledge on its effect on species’ thermal responses. We investigated whether changes in environmental thermal variability caused by urbanization influence thermal tolerance in honey bees (Apis mellifera) in a semi-arid city in central Mexico. Ambient environmental temperature and honey bee thermal tolerance were compared in urban and rural sites. Ambient temperature variability decreased with urbanization due to significantly higher nighttime temperatures in urban compared to rural sites and not from differences in maximum daily temperatures. Honey bee thermal tolerance breadth [critical thermal maxima (CT_max)—critical thermal minima (CT_min)] was narrower for urban bees as a result of differences in cold tolerance, with urban individuals having significantly higher CT_min than rural individuals, and CT_max not differing among urban and rural individuals. Honey bee body size was not correlated to thermal tolerance, and body size did not differ between urban and rural individuals. We found that honey bees’ cold tolerance is modified through acclimation. Our results show that differences in thermal variability along small spatial scales such as urban-rural gradients can influence species’ thermal tolerance breadths.

Tracking microhabitat temperature variation with iButton data loggers

PREMISE OF THE STUDY

Fine-scale variation in temperature and soil moisture contribute to microhabitats across the landscape, affecting plant phenology, distribution, and fitness. The recent availability of compact and inexpensive temperature and humidity data loggers such as iButtons has facilitated research on microclimates.

METHODS AND RESULTS

Here, we highlight the use of iButtons in three distinct settings: comparisons of empirical data to modeled climate data for rare rock ferns in the genus Asplenium in eastern North America; generation of fine-scale data to predict flowering time and vernalization responsiveness of crop wild relatives of chickpea from southeastern Anatolia; and measurements of extreme thermal variation of solar array installations in Vermont.

DISCUSSION

We highlight a range of challenges with iButtons, including serious limitations of the Hygrochron function that affect their utility for measuring soil moisture, and methods for protecting them from the elements and from human interference. Finally, we provide MATLAB code to facilitate the processing of raw iButton data.

Limited prospects for future alpine treeline advance in the Canadian Rocky Mountains

Treeline advance has occurred throughout the twentieth century in mountainous regions around the world; however, local variation and temporal lags in responses to climate warming indicate that the upper limits of some treelines are not necessarily in climatic equilibrium. These observations suggest that factors other than climate are constraining tree establishment beyond existing treelines. Using a seed addition experiment, we tested the effects of seed availability, predation and microsite limitation on the establishment of two subalpine tree species (Picea engelmannii and Abies lasiocarpa) across four treelines in the Canadian Rocky Mountains. The effect of vegetation removal on seedling growth was also determined, and microclimate conditions were monitored. Establishment limitations observed in the field were placed in context with the effects of soil properties observed in a parallel experiment. The seed addition experiment revealed reduced establishment with increasing elevation, suggesting that although establishment within the treeline ecotone is at least partially seed limited, other constraints are more important beyond the current treeline. The effects of herbivory and microsite availability significantly reduced seedling establishment but were less influential beyond the treeline. Microclimate monitoring revealed that establishment was negatively related to growing season temperatures and positively related to the duration of winter snow cover, counter to the conventional expectation that establishment is limited by low temperatures. Overall, it appears that seedling establishment beyond treeline is predominantly constrained by a combination of high soil surface temperatures during the growing season, reduced winter snowpack and unfavourable soil properties. Our study supports the assertion that seedling establishment in alpine treeline ecotones is simultaneously limited by various climatic and nonclimatic drivers. Together, these factors may limit future treeline advance in the Canadian Rocky Mountains and should be considered when assessing the potential for treeline advance in alpine systems elsewhere.

Effects of environmental variables on the calling behaviour of Northern Leopard Frogs (Lithobates pipiens) in Alberta, Canada

Breeding behaviour of Temperate Zone amphibians is influenced by environmental variables, but the initiation of calling (phenology) and influences on calling activity may vary with species and region. We investigated the influence of the timing of ice melt, water temperature, and photoperiod on the breeding phenology of the Northern Leopard Frog (Lithobates pipiens (Schreber, 1782)) in southern Alberta, Canada, using automated recording units. We also examined the influence of wind speed, relative humidity, water temperature, and time of day on calling activity. The initiation of calling varied by 13 days at our three sites, suggesting that calling was influenced more by water temperature and timing of ice melt than photoperiod. Calling was first observed 8–11 days after ice melt at water temperatures of 7.5–8 °C at our sites. No calling was detected at water temperature <5 °C. We recorded nocturnal and diurnal calling at all sites; >50% of calling was diurnal, even on days with warm overnight temperatures. Calling activity was influenced by time of day, water temperature, wind, and relative humidity. Our results suggest that date of initiation of calling varies considerably among breeding ponds and that the time of day of peak calling varies with both site and water temperature.

Long-distance transport of hair lambs: effect of location in pot-belly trailers on thermo-physiology, welfare and meat quality

Livestock transport exposes animals to a range of potential stressors that may compromise their welfare and final product quality, and those effects typically increase with the distance travelled. In North America, producers often use pot-belly vehicles for long hauls but little is known about their suitability for transporting lambs. We followed two long-distance trips using pot-belly trailers carrying 500 lambs (each) from Northern to Central Mexico in winter, to measure possible effects on animal welfare and meat quality. Sixty lambs per trip were placed at different locations within the pot-belly trailer. Animals were equipped with iButton Thermochron® temperature devices, which registered body temperature throughout pre- and post-slaughter stages. Despite the rather cool winter conditions, lambs placed in the "belly" and "nose" compartments had higher body temperatures at loading, during transport and lairage and after slaughter (carcass temperature). Those lambs also had higher levels of plasma cortisol, glucose and creatine kinase (CK), and a higher neutrophil/lymphocyte ratio. Regarding meat quality, ultimate pH (24 h) was higher in all locations, especially in LT4 location. Overall, the results suggest a link between thermal stress during transport, elevated physiological indicators of stress and poorer meat quality.

Measurement of bovine body and scrotal temperature using implanted temperature sensitive radio transmitters, data loggers and infrared thermography

Synchronous and continuous measurement of body (BT) and scrotal temperature (ST) without adverse welfare or behavioural interference is essential for understanding thermoregulation of the bull testis. This study compared three technologies for their efficacy for long-term measurement of the relationship between BT and ST by means of (1) temperature sensitive radio transmitters (RT), (2) data loggers (DL) and (3) infrared imaging (IRI). After an initial pilot study on two bulls to establish a surgical protocol, RTs and DLs were implanted into the flank and mid-scrotum of six Wagyu bulls for between 29 and 49 days. RT frequencies were scanned every 15 min, whilst DLs logged every 30 min. Infrared imaging of the body (flank) and scrotum of each bull was recorded hourly for one 24-h period and compared to RT and DL data. After a series of subsequent heat stress studies, bulls were castrated and testicular tissue samples processed for evidence of histopathology. Radio transmitters were less reliable than DLs; RTs lost >11 % of data, whilst 11 of the 12 DLs had 0 % data loss. IRI was only interpretable in 35.8 % of images recorded. Pearson correlations between DL and RT were strong for both BT (r > 0.94, P < 0.001) and ST (r > 0.80, P < 0.001). Surgery produced temporary minor inflammation and scrotal hematoma in two animals post-surgery. Whilst scar tissue was observed at all surgical sutured sites when bulls were castrated, there was no evidence of testicular adhesion and normal active spermatogenesis was observed in six of the eight implanted testicles. There was no significant correlation of IRI with either DL or RT. We conclude that DLs provided to be a reliable continuous source of data for synchronous measurement of BT and ST.

Lizard Activity and Abundance Greater in Burned Habitat of a Xeric Montane Forest

Restoring the natural or historical state of ecosystems is a common objective among resource managers, but determining whether desired system responses to management actions are occurring is often protracted and challenging. For wildlife, the integration of mechanistic habitat modeling with population monitoring may provide expedited measures of management effectiveness and improve understanding of how management actions succeed or fail to recover populations. Southern Appalachia is a region of high biodiversity that has undergone dramatic change as a result of human activities such as historic logging, exotic invasions, and alteration of disturbance regimes—including reduction in application of fire. Contemporary efforts to restore fire-maintained ecosystems within southern Appalachian forests require tools to assess the effects of fire management practices on individual animal fitness and relate them to corresponding influences on species abundance. Using automated sensing equipment, we investigated the effects of burned forests on reptile habitat suitability within the western portion of Great Smoky Mountains National Park, Tennessee. Specifically, we used microclimate measurements to model northern fence lizard Sceloporus undulatus hyacinthinus diurnal activity budgets in unburned and variable burn age (3–27-y) forest stands. We estimated northern fence lizard occurrence and abundance along transects through burned and unburned forests. Burned forest stands had microclimates that resulted in longer modeled daily activity periods under most conditions during summer. S. undulatus abundance was 4.75 times greater on burned stands compared to paired unburned stands, although the relationship between burn age and abundance was not well determined. Results suggest the more open habitat structure of burned areas within these xeric pine–oak forests may benefit S. undulatus.

Using Diurnal Temperature Signals to Infer Vertical Groundwater-Surface Water Exchange

Heat is a powerful tracer to quantify fluid exchange between surface water and groundwater. Temperature time series can be used to estimate pore water fluid flux, and techniques can be employed to extend these estimates to produce detailed plan-view flux maps. Key advantages of heat tracing include cost-effective sensors and ease of data collection and interpretation, without the need for expensive and time-consuming laboratory analyses or induced tracers. While the collection of temperature data in saturated sediments is relatively straightforward, several factors influence the reliability of flux estimates that are based on time series analysis (diurnal signals) of recorded temperatures. Sensor resolution and deployment are particularly important in obtaining robust flux estimates in upwelling conditions. Also, processing temperature time series data involves a sequence of complex steps, including filtering temperature signals, selection of appropriate thermal parameters, and selection of the optimal analytical solution for modeling. This review provides a synthesis of heat tracing using diurnal temperature oscillations, including details on optimal sensor selection and deployment, data processing, model parameterization, and an overview of computing tools available. Recent advances in diurnal temperature methods also provide the opportunity to determine local saturated thermal diffusivity, which can improve the accuracy of fluid flux modeling and sensor spacing, which is related to streambed scour and deposition. These parameters can also be used to determine the reliability of flux estimates from the use of heat as a tracer.

Diversity of fungi from the mound nests ofFormica ulkeiand adjacent non-nest soils

Culture-based methods were employed to recover 3929 isolates of fungi from soils collected in May and July 2014 from mound nests of Formica ulkei and adjacent non-nest sites. The abundance, diversity, and richness of species from nest mounds exceeded those of non-mound soils, particularly in July. Communities of fungi from mounds were more similar to those from mounds than non-mounds; this was also the case for non-mound soils with the exception of one non-mound site in July. Species of Aspergillus, Paecilomyces, and Penicillium were dominant in nest soils and represented up to 81.8% of the taxa recovered. Members of the genus Aspergillus accounted for the majority of Trichocomaceae from nests and were represented almost exclusively by Aspergillus navahoensis and Aspergillus pseudodeflectus. Dominant fungi from non-mound sites included Cladosporium cladosporioides, Geomyces pannorum, and species of Acremonium, Fusarium, Penicillium, and Phoma. Although mound nests were warmer than adjacent soils, the dominance of xerotolerant Aspergillus in soils from mounds and the isolation of the majority of Trichocomaceae at 25 and 35 °C suggests that both temperature and water availability may be determinants of fungal community structure in nests of F. ulkei.

Thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road

The study was conducted to evaluate the thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road. A total of 44 Chamarita breed adult ewes were randomly allotted to one of two groups, one control group (untransported) and transported group (journey of 4 h), and blood stress indicators were measured 1 day before transport and at four time points post-transport (0, 4 and 24 h). Thermophysiological profiles of ewes were measured by temperature buttons (iButton Thermochron^® ) and placed in intravaginal sponges. Direct observations, with a combination of scan and behaviour sampling, were carried out to collect information on individual behaviour and the time it took the ewes to drink water, eat and rest after returning to their pen respectively. Transported ewes lost approximately 1 kg live weight compared to controls and had higher body temperatures until 12 h post-transport. Cortisol, glucose, non-esterified fatty acid (NEFA) concentrations as well as the neutrophil-lymphocyte ratio (N/L) and other physiological indicators were higher immediately after unloading in transported ewes but mostly returned to normal after 4 h, with complete recovery after 24 h. Behavioural analysis post-transport demonstrated that transported ewes chose to eat before drinking and spent less time resting than controls in the first 3 h after unloading. The study demonstrates that transportation even under short-journey conditions induced behavioural, physiological and thermophysiological responses indicative of the induction of significant stress, leading to live weight shrinkage that may jeopardize farmer's incomes. Finally, results of this study validated the use of iButton Thermochron^® data loggers for monitoring the stress response during transport.

Population differentiation and countergradient variation throughout the geographic range in the fern gametophyte Vittaria appalachiana

PREMISE OF THE STUDY

Theory predicts that limited gene flow between populations will promote population differentiation, and experimental studies have found that differentiation is often explained by local adaptation in sexually reproducing angiosperms. However, few experiments have examined the drivers of differentiation among populations in asexual land plants with limited dispersal potential. Here, we evaluated the role of temperature in driving population differentiation in an asexual, obligate gametophyte fern species.

METHODS

We reciprocally transplanted Vittaria appalachiana gametophytes among six populations that spanned the species' geographic range in the Appalachian Mountains and Plateau. Temperature, survival, and senescence rates were measured for 1 year.

KEY RESULTS

Populations had significantly different fitness responses to different sites, consistent with the hypothesis that populations have differentiated across the species' range. There was some evidence for local adaptation in marginal populations and for countergradient selection favoring particularly robust genotypes at the northern range edge. Most populations had relatively high fitness at the site with the most stable temperature conditions and were negatively affected by decreasing minimum temperatures.

CONCLUSIONS

Populations of Vittaria appalachiana exhibit highly variable responses to transplantation across the species' range, and only a small subset of these responses are due to local adaptation. Differences in daily minimum temperature explain some variation in fitness, but other site-specific factors also have significant impacts on transplant fitness. These results indicate that asexual, patchily distributed species with limited dispersal may exhibit population-specific responses to global climate change that have not been elucidated by empirical work focused on sexually reproducing angiosperms.

Natural disturbance reduces disease risk in endangered rainforest frog populations

Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture, and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis). Reductions in canopy cover increased the temperatures and rates of evaporative water loss in frog microhabitats, which reduced B. dendrobatidis infection risk in frogs by an average of 11–28% in cyclone-damaged areas, relative to unaffected areas. Natural disturbances to the rainforest canopy can therefore provide an immediate benefit to frogs by altering the microclimate in ways that reduce infection risk. This could increase host survival and reduce the probability of epidemic disease outbreaks. For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.

Seasonal Ecology and Behavior of an Endangered Rainforest Frog (Litoria rheocola) Threatened by Disease

One of the most devastating wildlife diseases ever recorded is chytridiomycosis, a recently emerged amphibian disease that is caused by the chytrid fungus Batrachochytrium dendrobatidis. Understanding, predicting, and managing the impacts of chytridiomycosis on any amphibian species will require detailed information on its ecology and behavior because this pathogen is transmitted by contact with water or other individuals, and pathogen growth rates are thermally sensitive. The common mistfrog (Litoria rheocola) is an endangered tropical rainforest frog that has declined due to chytridiomycosis. We tracked L. rheocola during the winter (cool/dry) and summer (warm/wet) seasons at a low- and high-elevation site. We found that seasonal differences in environmental temperatures and frog behavior should render this species most vulnerable to B. dendrobatidis during cooler months and at higher elevations, which matches observed patterns of infection prevalence in this species. During winter, frogs moved shorter distances than during summer, and they spent less time in vegetation and more time in the stream, which should increase exposure to aquatic B. dendrobatidis zoospores. At a low-elevation site (40 m ASL), estimated body temperatures were within the optimal range for B. dendrobatidis growth (15-25°C) most of the time during winter, but they reached temperatures above this threshold frequently in summer. At a higher elevation (750 m ASL), estimated body temperatures were within the range most favorable for B. dendrobatidis year-round, and did not exceed 25°C, even during summer. Our study provides the first detailed information on the ecology and behavior of L. rheocola and suggests ecological mechanisms for infection dynamics that have been observed in this endangered species.

Effects of timber harvests and silvicultural edges on terrestrial salamanders

Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (<20 m). Small harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years. Long-term monitoring will be necessary to understand the full impacts of forest management on terrestrial salamanders.

Using pairs of physiological models to estimate temporal variation in amphibian body temperature

Physical models are often used to estimate ectotherm body temperatures, but designing accurate models for amphibians is difficult because they can vary in cutaneous resistance to evaporative water loss. To account for this variability, a recently published technique requires a pair of agar models that mimic amphibians with 0% and 100% resistance to evaporative water loss; the temperatures of these models define the lower and upper boundaries of possible amphibian body temperatures for the location in which they are placed. The goal of our study was to develop a method for using these pairs of models to estimate parameters describing the distributions of body temperatures of frogs under field conditions. We radiotracked green-eyed treefrogs (Litoria serrata) and collected semi-continuous thermal data using both temperature-sensitive radiotransmitters with an automated datalogging receiver, and pairs of agar models placed in frog locations, and we collected discrete thermal data using a non-contact infrared thermometer when frogs were located. We first examined the accuracy of temperature-sensitive transmitters in estimating frog body temperatures by comparing transmitter data with direct temperature measurements taken simultaneously for the same individuals. We then compared parameters (mean, minimum, maximum, standard deviation) characterizing the distributions of temperatures of individual frogs estimated from data collected using each of the three methods. We found strong relationships between thermal parameters estimated from data collected using automated radiotelemetry and both types of thermal models. These relationships were stronger for data collected using automated radiotelemetry and impermeable thermal models, suggesting that in the field, L. serrata has a relatively high resistance to evaporative water loss. Our results demonstrate that placing pairs of thermal models in frog locations can provide accurate estimates of the distributions of temperatures experienced by individual frogs, and that comparing temperatures from model pairs to direct measurements collected simultaneously on frogs can be used to broadly characterize the skin resistance of a species, and to select which model type is most appropriate for estimating temperature distributions for that species.

Potential sources of intra-population variation in painted turtle (Chrysemys picta) hatchling overwintering strategy

Many temperate animals spend half their lives in a non-active, overwintering state, and multiple adaptations have evolved to enable winter survival. One notable vertebrate model is Chrysemys picta whose hatchlings display dichotomous overwintering strategies: some hatchlings spend their first winter aquatically after nest emergence in fall, while others overwinter terrestrially within their natal nest with subsequent spring emergence. Occurrence of these strategies varies among populations and temporally within populations; however, factors that determine the strategy employed by a nest in nature are unknown. We examined potential factors that influence intra-population variation in C. picta hatchling overwintering strategy over two winters in Algonquin Park, Ontario. We found that environmental factors may be a trigger for hatchling overwintering strategy: fall-emerging nests were sloped towards the water and were surrounded by a relatively higher percentage of bare ground compared to spring-emerging nests. Fall-emerging hatchlings were also relatively smaller. Overwintering strategy was not associated with clutch oviposition sequence, or mammalian or avian predation attempts. Instead, fall emergence from the nest was associated with the direct mortality threat of predation by Sarcophagid fly larvae. Body condition and righting response, measured as proxies of hatchling fitness, did not differ between overwintering strategies. Costs and benefits of overwintering aquatically versus terrestrially in hatchling C. picta are largely unknown, and have the potential to affect population dynamics. Understanding winter survival has great implications for turtle ecology, thus we emphasize future research areas on dichotomous overwintering strategies in temperate hatchling turtles.

Elevation, temperature, and aquatic connectivity all influence the infection dynamics of the amphibian chytrid fungus in adult frogs

Infectious diseases can cause population declines and even extinctions. The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), has caused population declines and extinctions in amphibians on most continents. In the tropics, research on the dynamics of this disease has focused on amphibian populations in mountainous areas. In most of these areas, high and low elevation sites are connected by an assemblage of streams that may transport the infectious stage of the pathogen from high to low elevations, and, also, this pathogen, which grows well at cool temperatures, may persist better in cooler water flowing from high elevations. Thus, the dynamics of disease at low elevation sites without aquatic connections to higher elevation sites, i.e., non-contiguous low elevation sites, may differ from dynamics at contiguous low elevation sites. We sampled adult common mistfrogs (Litoria rheocola) at six sites of three types: two at high (> 400m) elevations, two at low elevations contiguous with high elevation streams, and two at low elevations non-contiguous with any high elevation site. Adults were swabbed for Bd diagnosis from June 2010 to June 2011 in each season, over a total of five sampling periods. The prevalence of Bd fluctuated seasonally and was highest in winter across all site types. Site type significantly affected seasonal patterns of prevalence of Bd. Prevalence remained well above zero throughout the year at the high elevation sites. Prevalence declined to lower levels in contiguous low sites, and reached near-zero at non-contiguous low sites. Patterns of air temperature fluctuation were very similar at both the low elevation site types, suggesting that differences in water connectivity to high sites may have affected the seasonal dynamics of Bd prevalence between contiguous and non-contiguous low elevation site types. Our results also suggest that reservoir hosts may be important in the persistence of disease at low elevations.

Evaluation of predator-exclusion cages used in turtle conservation: cost analysis and effects on nest environment and proxies of hatchling fitness

Context A main goal of conservation is to mitigate anthropogenic impacts on natural ecosystems, thus conservation tools themselves should not negatively affect target species. Predator-exclusion cages are effectively used to reduce predation of turtle nests; however, their effects on nest environment and developing hatchlings have not been examined. Aims Our study had the following four goals: (1) to examine effects of cages on the nest environment, (2) determine whether nest caging affects proxies for hatchling fitness, (3) evaluate whether nest predators preferentially interact with certain cage types, and (4) assess the cost-effectiveness of different nest caging designs. Methods In 2010 and 2011 in Algonquin Provincial Park, Ontario, painted turtle (Chrysemys picta; n = 93) and snapping turtle (Chelydra serpentina; n = 91) nests were assigned to one of three treatments (wooden-sided cages, above- and below-ground wire cages) or a control (no nest cage) and outfitted with a data logger to record incubation temperature. After emergence, hatching success and proxies of hatchling fitness were measured. Key results Nest temperature, hatching success, frequency of hatchling deformities and locomotor performance did not differ among cage treatments. However, hatchling body condition differed among treatments; wooden-sided and below-ground cages had the most positive influence on body condition in painted and snapping turtles, respectively. Predator interactions did not differ among treatments, and wooden-sided cages were the most inexpensive to construct. Conclusions Nest cages did not alter the nest environment from natural conditions but did alter hatchling body condition, and nest caging affected species differently. Implications Nest cages are known to reduce nest depredation, and our data indicated that, in general, nest cages also do not affect the nest environment or proxies for hatchling fitness. Thus, our findings indicated that cages are effective conservation tools that do not present secondary deleterious effects on potential recruitment.