Microclimate Preferences Research Articles

The affinity of vascular plants and bryophytes to forest microclimate buffering

Abstract With recent advances in technology and modelling, ecologists are increasingly advised to use microclimate, not the usual coarse scale macroclimate based on weather stations, to better reflect the proximal conditions that species experience. This is especially relevant in forest ecosystems, where natural disturbances and management create substantial heterogeneity in microclimates. Under dense canopies, species may experience buffered (less extreme) microclimate temperatures relative to macroclimate, as well as increased relative humidity, reduced light and wind. Focusing on understorey plants, we investigated species response curves to the buffering capacity of the canopy layer, measured as the log‐transformed slope parameter of the microclimate to macroclimate linear relationship. If lower or higher than zero, microclimate temperatures are buffered or amplified, respectively, relative to macroclimate. During leaf‐on conditions (July–September 2021), we measured hourly microclimate temperatures in 157 plots across three temperate deciduous forests with contrasted macroclimates. We used paired hourly macroclimate measurements from nearby weather stations to derive the slope parameter, quantifying microclimate buffering. We surveyed vascular plant and bryophyte communities in 400 m2 plots centred on our microclimate sensors. Species were classified into three groups of forest affinity: core specialists; edge specialists; and generalists. We fitted generalized linear mixed‐effects models, by forest affinity group and by species, to obtain logistic response curves of the probability of occurrence against microclimate buffering. The species' optimum was computed as the microclimate effect that maximizes the species' probability of presence. We found contrasted microclimate preferences: Most bryophytes as well as the vascular plants classified as forest core specialists had an optimum in microclimate buffering, while forest edge specialists and generalists among vascular plants had an optimum in microclimate amplification. As canopies undergo increased disturbance frequency and intensity, more generalists and less forest core specialists might thus be expected in understorey communities, especially for bryophytes. Synthesis. Understorey plants have a species‐specific affinity to the forest microclimate, which we quantify for the first time. The investigation of species response curves to microclimate processes—buffering or amplification—can improve our understanding of the ecology of understorey plants, and help us anticipate their redistribution under climate change.

Study on the elderly's perception of microclimate and activity time in residential communities

The significance of outdoor environment is increasingly being recognized, particularly for the elderly. Using residential community green spaces is beneficial for their physical and mental health. This study aims to explore the thermal comfort, usage patterns, and microclimate preferences of the elderly through environmental factors and demographic information. Field measurements and questionnaire surveys were conducted across 19 residential communities in 3 cities within Building Climate Zone II in China during the summer. Descriptive and logistic regression analyses were employed to examine various factors related to the elderly's thermal comfort, duration of activity, and microclimate preferences. The study revealed that elderly residents in communities of various types experience different thermal comfort levels and have different durations of activity and preferences for microclimates. In addition, elderly adults with longer activity durations are less likely to prefer windless, drier, and more sunlight environments in the summer. Built environmental factors, personal factors, and features of public facilities were also found to have an impact on thermal comfort and activity. These empirical findings provide urban planners with insights to better cater to the needs of the elderly in residential area design, emphasizing the importance of considering thermal comfort and microclimate preferences in the planning process.

Micro‐ and macroclimate interactively shape diversity, niches and traits of Orthoptera communities along elevational gradients

AbstractAimTemperature is one of the main drivers shaping species diversity and assembly processes. Yet, site‐specific effects of the local microclimate on species and trait compositions of insect communities have rarely been assessed along macroclimatic temperature clines.LocationBavarian Alps, Germany.MethodsBayesian joint species distribution models were applied to investigate how ecological and morphological traits drive variation in the climatic niches of 32 Orthoptera species on 93 grassland sites with contrasting microclimatic conditions along a steep elevational macroclimatic gradient in an Alpine region in Central Europe.ResultsSpecies richness and abundance decreased along the elevational macroclimatic gradient, and both benefitted from warm microclimate. Interactive effects of elevation and microclimate on the abundance were, however, species‐specific, and partly mediated by traits: Warm microclimatic conditions facilitated the occurrence of demanding xerophilic and late‐hatching species, resulting in marked community dissimilarities at mid‐elevations where colder sites harboured only a subset of the species. The latter mainly occurred at low elevations together with long‐winged species. Abundance peaks of non‐xerophilic species were further upslope when microclimate was warm. Intraspecifically, the body sizes and wing lengths of the larger females, but not the males, decreased with elevation akin the community mean, and brown colour morphs were more frequent at sites with warm microclimate.Main ConclusionsOur nuanced results reveal that trait‐dependent responses of species to microclimate play a key role in the assembly and structuring of insect communities along macroclimatic gradients. Since microclimate preferences changed with elevation, we conclude that species temperature niches are narrower than the elevational range suggests and both macro‐ and microclimatic conditions must be considered when predicting species responses to climate change. Microclimatic contrasts among sites at similar elevations enhanced species turnover mediated by moisture preferences and phenology, highlighting the importance of mountains for conservation as climatic refugia where species with diverging niches can persist in proximity.

Microhabitat and Microclimate Preferences of Anuran Species Inhabiting Restoration and Adjacent Forest of Cameron Highlands, Pahang, Malaysia

The conversion of forests to agricultural farmland modifies lands into small patches, making amphibians more susceptible to external environmental changes. It is important to restore the forest ecosystem so that fauna species, especially anurans, could gradually recover and help create a balanced ecosystem in the restoration process. The aims of this study are to determine diversity, richness, and evenness of the anuran species, and to investigate the relationship of the anuran species with environmental variables of restoration areas and adjacent forests of Terla Forest Reserve (FR), Cameron Highlands, Pahang. The study recorded 14 species belonging to six families with higher species diversity, whereby the Shannon Wiener (H’) value in the adjacent forest (H’ = 1.71) was higher as compared to the restoration area (H’ = 0.77). The anuran species in the restoration area showed an adaptation to bare soil, herbs, and shrubs. Meanwhile, in the forest, forest litter was favoured by the anuran species. Species abundance demonstrated correlation towards microclimate. The adaption of two species to the restoration area showed that temperature had a significant and negative correlation with Duttaphrynus melanostictus; relative humidity was significant and positively correlated with Polypedates leucomystax; while relative humidity had a significant and negative correlation with Microhyla annectens, a forest specialist. A deeper understanding of environmental factors that affect the presence of anurans, especially in restoration areas, can facilitate forest management in evaluating the effectiveness of forest restoration in this region.

Canopy distribution and microclimate preferences of sterile and wild Queensland fruit flies

Insects tend to live within well-defined habitats, and at smaller scales can have distinct microhabitat preferences. These preferences are important, but often overlooked, in applications of the sterile insect technique. Different microhabitat preferences of sterile and wild insects may reflect differences in environmental tolerance and may lead to spatial separation in the field, both of which may reduce the control program efficiency. In this study, we compared the diurnal microhabitat distributions of mass-reared (fertile and sterile) and wild Queensland fruit flies, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). Flies were individually tagged and released into field cages containing citrus trees. We recorded their locations in the canopies (height from ground, distance from canopy center), behavior (resting, grooming, walking, feeding), and the abiotic conditions on occupied leaves (temperature, humidity, light intensity) throughout the day. Flies from all groups moved lower in the canopy when temperature and light intensity were high, and humidity was low; lower canopy regions provided shelter from these conditions. Fertile and sterile mass-reared flies of both sexes were generally lower in the canopies than wild flies. Flies generally fed from the top sides of leaves that were lower in the canopy, suggesting food sources in these locations. Our observations suggest that mass-reared and wild B. tryoni occupy different locations in tree canopies, which could indicate different tolerances to environmental extremes and may result in spatial separation of sterile and wild flies when assessed at a landscape scale.

Body mass and hibernation microclimate may predict bat susceptibility to white-nose syndrome.

In multihost disease systems, differences in mortality between species may reflect variation in host physiology, morphology, and behavior. In systems where the pathogen can persist in the environment, microclimate conditions, and the adaptation of the host to these conditions, may also impact mortality. White‐nose syndrome (WNS) is an emerging disease of hibernating bats caused by an environmentally persistent fungus, Pseudogymnoascus destructans. We assessed the effects of body mass, torpid metabolic rate, evaporative water loss, and hibernaculum temperature and water vapor deficit on predicted overwinter survival of bats infected by P. destructans. We used a hibernation energetics model in an individual‐based model framework to predict the probability of survival of nine bat species at eight sampling sites across North America. The model predicts time until fat exhaustion as a function of species‐specific host characteristics, hibernaculum microclimate, and fungal growth. We fit a linear model to determine relationships with each variable and predicted survival and semipartial correlation coefficients to determine the major drivers in variation in bat survival. We found host body mass and hibernaculum water vapor deficit explained over half of the variation in survival with WNS across species. As previous work on the interplay between host and pathogen physiology and the environment has focused on species with narrow microclimate preferences, our view on this relationship is limited. Our results highlight some key predictors of interspecific survival among western bat species and provide a framework to assess impacts of WNS as the fungus continues to spread into western North America.

Male long-distance migrant turned sedentary; The West European pond bat (Myotis dasycneme) alters their migration and hibernation behaviour.

During autumn in the temperate zone, insectivorous male bats face a profound energetic challenge, as in the same period they have to make energy choices related to hibernation, mating and migration. To investigate these energetic trade-offs, we compared the body mass of male and female pond bats (Myotis dasycneme) through the summer season, characterized the known hibernacula in terms of male or female bias, and subsequently compared their population trend during two study periods, between 1930–1980 and 1980–2015. Towards the end of summer, males began losing weight whilst females were simultaneously accumulating fat, suggesting that males were pre-occupied with mating. We also found evidence for a recent adaptation to this energetic trade-off, males have colonised winter roosts in formerly unoccupied areas, which has consequently led to a change in the migration patterns for the male population of this species. As male bats do not assist in raising offspring, males have ample time to restore their energy balance after hibernation. Our results suggest that choosing a hibernacula closer to the summer range not only decreases energy cost needed for migration, it also lengthens the mating season of the individual male. Our findings have important conservation implications, as male and female biased hibernation assemblages may differ critically in terms of microclimate preferences.

Exotic Epiphytes on Tree Ferns in Cibodas Botanical Gardens: The Importance of Light Preferences and Host Characteristics

The study of exotic epiphytes on tree ferns is relatively scarce. Biological invasion of exotic epiphytes may imply negative consequences to native epiphytes and tree ferns, which are important components in tropical mountainous rainforest ecosystems. This study surveyed exotic epiphytes on tree ferns in Cibodas Botanical Gardens (CBG) and adjacent forests next to CBG. The objectives of this study are: a) to conduct inventory study of exotic epiphyte species on tree ferns, b) to examine how different these exotic epiphytes from each other based on their micro-climate preferences, c) to conduct invasive risk assessment of those exotic epiphytes, and d) to model the effect of environmental factors and host (tree ferns) characteristics to the occurrence of exotic epiphytes on tree ferns. We conducted multi-dimensional analysis to examine how different these exotic epiphytes based on their micro-climate parameters. We used Weed Risk Assessment (WRA) framework to estimate the invasion risks of surveyed exotic epiphytes. We performed Bayesian logistic regression to test the correlation between environmental and host characteristics and the occurrence probability of exotics epiphytes on tree ferns. We found 13 exotic epiphyte species on two native tree ferns species ( Cyathea junghuhniana and Cyathea contaminans ). Multidimensional analysis showed that Axonopus compressus is very different from other exotic epiphytes due to its environmental preferences. Ageratina riparia and Clidemia hirta were exotic epiphytes with the highest invasion risks. Therefore, we suggested that A. riparia and C. hirta are more likely to become invasive and may contribute significant impacts to native ecosystems. Lastly, the presence of Austroeupatorium inulaefolium as exotic epiphytes in tree ferns negatively correlated with the host height. Further study is needed to incorporate biological traits of the exotic epiphytes and more specific environmental parameters such as light chromatic quality in to the exotic epiphyte occurrence model. This study provides evidence for the existences of exotic epiphytes on tree ferns. The result of this study may also indicate that host characteristics and micro-climate factors could play important roles to inhibit the occurrence of exotic epiphytes on tree ferns.

Drivers of variation in species impacts for a multi-host fungal disease of bats.

Disease can play an important role in structuring species communities because the effects of disease vary among hosts; some species are driven towards extinction, while others suffer relatively little impact. Why disease impacts vary among host species remains poorly understood for most multi-host pathogens, and factors allowing less-susceptible species to persist could be useful in conserving highly affected species. White-nose syndrome (WNS), an emerging fungal disease of bats, has decimated some species while sympatric and closely related species have experienced little effect. We analysed data on infection prevalence, fungal loads and environmental factors to determine how variation in infection among sympatric host species influenced the severity of WNS population impacts. Intense transmission resulted in almost uniformly high prevalence in all species. By contrast, fungal loads varied over 3 orders of magnitude among species, and explained 98% of the variation among species in disease impacts. Fungal loads increased with hibernating roosting temperatures, with bats roosting at warmer temperatures having higher fungal loads and suffering greater WNS impacts. We also found evidence of a threshold fungal load, above which the probability of mortality may increase sharply, and this threshold was similar for multiple species. This study demonstrates how differences in behavioural traits among species-in this case microclimate preferences-that may have been previously adaptive can be deleterious after the introduction of a new pathogen. Management to reduce pathogen loads rather than exposure may be an effective way of reducing disease impact and preventing species extinctions.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.

Life Inside an Acorn: How Microclimate and Microbes Influence Nest Organization in Temnothorax Ants

AbstractNests provide a buffer against environmental variation, but conditions may also vary at different locations within a nest. Conditions can vary based on abiotic factors, such as moisture and temperature, as well as biotic factors, such as the presence of microbes and potential pathogens. Therefore, characterizing how animals adjust their position inside their nests to track microclimate preferences while at the same time preventing pathogen exposure is necessary to understand the benefits nests provide. Here we studied how colonies of the acorn‐nesting ant Temnothorax curvispinosus responded to experimental manipulation of moisture, temperature, and microbial growth inside their nests. Colonies showed no response to differences in moisture and moved to the bottom of the acorn regardless of moisture treatment. When nests were heated from the top to simulate warming by the sun, workers preferentially moved brood to the warm, upper half of the acorn, which would stimulate brood development. Finally, the strongest factor that influenced colony position was the presence of microbes inside the nest—colonies avoided the bottom of the nest when it was inoculated with microbes, and colonies in new acorns shifted to the top of the acorn over time as mold and other microbes had time to grow. The relatively strong response of T. curvispinosus to microbial growth inside their nests suggests that pathogen pressures—in addition to microclimate—have a significant impact on how colonies use nest spaces. Social insects are known to invest heavily in antimicrobial compounds that kill or slow the growth of microbes, but avoidance may represent an additional line of defense to prevent pathogen exposure.

Microclimate predicts within‐season distribution dynamics of montane forest birds

AbstractAimClimate changes are anticipated to have pervasive negative effects on biodiversity and are expected to necessitate widespread range shifts or contractions. Such projections are based upon the assumptions that (1) species respond primarily to broad‐scale climatic regimes, or (2) that variation in climate at fine spatial scales is less relevant at coarse spatial scales. However, in montane forest landscapes, high degrees of microclimate variability could influence occupancy dynamics and distributions of forest species. Using high‐resolution bird survey and under‐canopy air temperature data, we tested the hypothesis that the high vagility of most forest bird species combined with the heterogeneous thermal regime of mountain landscapes would enable them to adjust initial settlement decisions to track their thermal niches.LocationWestern Cascade Mountains, Oregon, USA.MethodsWe used dynamic occupancy models to test the degree to which microclimate affects the distribution patterns of forest birds in a heterogeneous mountain environment. In all models we statistically accounted for vegetation structure, vegetation composition and potential biases due to imperfect detection of birds. We generated spatial predictions of forest bird distributions in relation to microclimate and vegetation structure.ResultsFine‐scale temperature metrics were strong predictors of bird distributions; effects of temperature on within‐season occupancy dynamics were as large or larger (1–1.7 times) than vegetation effects. Most species (86.7%) exhibited apparent within‐season occupancy dynamics. However, species were almost as likely to be warm associated (i.e., apparent settlement at warmer sites and/or vacancy at cooler sites; 53.3% of species) as cool associated (i.e., apparent settlement at cooler sites and/or vacancy at warmer sites; 46.7% of species), suggesting that microclimate preferences are species specific.Main conclusionsHigh‐resolution temperature data increase the quality of predictions about avian distribution dynamics and should be included in efforts to project future distributions. We hypothesize that microclimate‐associated distribution patterns may reflect species' potential for behavioural buffering from climate change in montane forest environments.

English

In Southern California, the red willow (Salix laevigata Bebb) hosts a variety of gall-inducing parasitic insects. However, little is known about the ecology of these parasites, particularly the characterization of their microclimate preferences. This study explores the relationship between microclimate and gall frequencies in S. laevigata in the Ballona Wetlands and Temescal Canyon, and gall count correlated with biotic and abiotic factors such as soil pH, soil moisture and willow density. Significantly more galls per leaf were found at Temescal Canyon than Ballona Wetlands. Although the number of galls per leaf correlated negatively with soil pH, soil moisture content and canopy openness, only site and gall location were found to significantly predict the number of galls. These results suggest that additional or interacting microclimate factors may influence gall frequencies between Temescal Canyon and the Ballona Wetlands. Key words: Insect galls, microclimate, plant vigor hypothesis, self-thinning rule.

Microclimate preferences correlate with contrasted evaporative water loss in parapatric vipers at their contact zone

Terrestrial ectotherms predominantly use behavioural means to thermoregulate and thereby optimize performances. However, thermoregulation can impart physiological challenges to other critical processes such as water balance by increasing evaporative water loss (EWL). Like thermoregulation, water balance is influenced by both external factors (e.g., microhabitat and environmental constraints) and endogenous traits (e.g., evaporative water loss rates, dehydration tolerance). Although thermoregulation and water balance are tightly linked, the role of water balance is often overlooked when evaluating species climatic adaptation and response to global warming. We studied two congeneric viperid species (the Aspic Viper, Vipera aspis (L., 1758), and the Common Viper, Vipera berus (L., 1758)) with contrasted climatic affinities (south European versus boreal, respectively). These parapatric species are syntopic in narrow contact zones where microhabitat partitioning has been reported. We compared total EWL and cutaneous evaporative water loss (CEWL) of the two species and monitored the thermal and hydric conditions of the microhabitats used in syntopic populations. We found that the boreal V. berus has greater EWL, both total and cutaneous. Accordingly, this species selected more humid microhabitats throughout the year. Humidity appears to be an important determinant of habitat selection, and therefore, V. berus is likely vulnerable to changing precipitation at the southern limit of its distribution.

Abundance and web characteristics of Micrathena gracilis and Micrathena mitrata (Araneae: Araneidae) in west-central Illinois, USA

We investigated abundance and web characteristics (web elevation and spiral area) of the spiny orb weavers Micrathena gracilis (Walckenaer 1805) and Micrathena mitrata (Hentz 1850) using transect surveys in oak-hickory forest stands in west-central Illinois. Surveys resulted in 153 collected individuals or observations of adult females (70 M. gracilis and 83 M. mitrata). Peak abundance of both species occurred in late July, with a density of 0.03 females per m 2 for each species. Web spiral area and web elevation were both greater for M. gracilis than M. mitrata. Micrathena mitrata web spiral area was larger in plots in which spiders had been previously removed than in plots without removal. These results suggest that the two species have different vegetation structure or microclimate preferences, and may respond to availability of unoccupied habitat differently.

Microclimate preferences during swarming and hibernation in the Townsend's big-eared bat,Corynorhinus townsendii

Townsend's big-eared bat (Corynorhinus townsendii) is a North American bat that hibernates in caves and mines. These underground habitats also are important roost sites during fall swarming, a period during which bats undergo preparation for hibernation. During swarming bats are very active at night, rousing frequently several times a night to fly within and between roosts. During hibernation nighttime activity is suppressed so that bats rouse and move infrequently. Daytime activity is suppressed during both periods by daily torpor. Both hibernacula and swarming roosts have particular thermal requirements associated with energetic optimization. Swarming roosts tend to have a higher minimum temperature than hibernacula, facilitating efficient arousal from torpor. Both roost types have low maximum temperatures, facilitating conservation of stored body fat resources. We explored and tested preferences of C. townsendii for microclimates in these habitats. Our results confirm that C. townsendii prefers habitats that are thermally constrained such that temperatures and related microclimate variables are optimum for swarming or hibernation activities.

Ground Beetle (Coleoptera: Carabidae) Activity Density and Community Composition in Vegetationally Diverse Corn Agroecosystems

-Influences of weeds on activity density (number captured per trap per day), species richness and diversity of carabids (Coleoptera: Carabidae) in reduced tillage corn (Zea mays L.) plantings were examined in a 2-yr field study. Four treatments were examined: corn monoculture, corn with broadleaved weeds, corn with grassy weeds, and corn with a mixture of broadleaved and grassy weeds. Carabids were sampled with pitfall traps every 34 wk from May to September in 1988 and 1989. Neither broadleafed nor grassy weeds significantly influenced carabid activity density in 1988, a year of severe drought. However, in 1989, a year of normal rainfall, activity density was significantly greater in broadleaved weed treatments. Activity density of each of the major carabid species was affected differently by the treatments. Weedy vegetation in corn plantings generally did not have significant effects on carabid species richness, and community similarity was generally high for all treatments. Weeds had a significant negative effect on corn yields; the possible beneficial effects of such vegetation on enhancement of carabid activity density should be compared to the potential negative effect of corn yield loss. These results suggest carabid species respond differently to vegetational diversity, perhaps due to a number of factors, including suitable prey availability and microclimate preferences.

Malaria Studies in Greece

Malaria Studies in Greece