Kathrin H Dausmann

• Prof. Dr.
• Professor at Hamburg University

Widespread species often display traits of generalists, yet local adaptations may limit their ability to cope with diverse environmental conditions. With climate change being a pressing issue, distinguishing between the general ecological and physiological capacities of a species and those of individual populations is vital for assessing the capabi...

Climate change is swiftly altering environmental winter conditions, leading to significant ecological impacts such as phenological shifts in many species. As a result, animals might face physiological mismatches due to longer or earlier activity periods and are at risk of being exposed to late spring freezes. Our study points for the first time to...

Climate change is swiftly altering environmental winter conditions, leading to significant ecological impacts such as phenological shifts in many species. As a result, animals might face physiological mismatches due to longer or earlier activity periods and are at risk of being exposed to late spring freezes. We investigated the physiological respo...

Simple Summary Amphibian biodiversity is declining around the globe and habitat destruction and fragmentation impact two-thirds of all amphibians. The distinct characteristics of amphibians, such as low mobility and permeable skin, make them more susceptible to environmental influences than other taxa. We have shown that within the small area of th...

Some species occur in higher densities in cities than in natural habitats, despite the variety of urban stressors. Urban fragments can be extremely heterogeneous though, and species’ responses might vary between urban patches. However, only few studies examine mammalian populations from different fragments in the core of cities, where stressors are...

Maintaining a high and stable body temperature as observed in most endothermic mammals and birds is energetically costly and many heterothermic species reduce their metabolic demands during energetic bottlenecks through the use of torpor. With the increasing number of heterotherms revealed in a diversity of habitats, it becomes apparent that trigge...

The ecophysiological responses of species to urbanisation reveal important information regarding the processes of successful urban colonization and biodiversity patterns in urban landscapes. Investigating these responses will also help uncover whether synurban species are indeed urban ‘winners’. Yet we still lack basic knowledge about the physiolog...

Urban wildlife faces a great variety of human-induced habitat alterations, among others changes in resource availability and composition, often resulting in serious declines in biodiversity. Nevertheless, Eurasian red squirrels (Sciurus vulgaris) occur in high densities in urban areas and seem to benefit from supplementary feeding. However, we stil...

Throughout the year, wild animals are exposed to a variety of challenges such as changing environmental conditions and reproductive activity. These challenges may affect their stress hormone levels for varying durations and in varying intensities and impacts. Measurements of the glucocorticoid hormone cortisol in the hair of mammals are considered...

Torpor is a highly effective response to counter various ecological and physiological bottlenecks in endotherms. In this study, we examined interrelations between thermoregulatory responses and key environmental variables in free-living squirrel gliders (Petaurus norfolcensis) in a habitat with drastic climatic and ecological changes across seasons...

Rapid environmental changes are challenging for endothermic species because they have direct and immediate impacts on their physiology by affecting microclimate and fundamental resource availability. Physiological flexibility can compensate for certain ecological perturbations, but our basic understanding of how species function in a given habitat...

Parasitic infections can impact the fitness of individuals and can have influence on animals’ population dynamics. An individuals’ parasite prevalence often changes depending on external or seasonal changes, e.g., rainfall and ambient temperatures, but also on internal changes, e.g., changes in body condition. In this study we aimed to identify the...

Phenotypic plasticity may allow ectotherms with complex life histories such as amphibians to cope with climate-driven changes in their environment. Plasticity in thermal tolerance (i.e., shifts of thermal limits via acclimation to higher temperatures) has been proposed as a mechanism to cope with warming and extreme thermal events. However, thermal...

Many species are widely distributed and individual populations can experience vastly different environmental conditions over seasonal and geographic scales. With such a broad ecological reality, datasets with limited spatial and temporal resolution may not accurately represent a species and could lead to poorly informed management decisions. Becaus...

Animals experience seasonal changes of environmental and ecological conditions in most habitats. Fluctuations in ambient temperature have a strong influence on thermoregulation, particularly on small endothermic mammals. However, different mammalian species cope differently with these changes. Understanding the physiological responses of organisms...

Studying animals under natural or semi‐natural conditions is essential to better understand the implications of a warming climate on species survival. Here, we provide evidence of the effects of increasing winter ambient temperature (Ta) on the thermal physiology, feeding behaviour and body mass (BM) of a small mammalian hibernator, the hazel dormo...

Many tropical mammals are vulnerable to heat because their water budget limits the use of evaporative cooling for heat compensation. Further increasing temperatures and aridity might consequently exceed their thermoregulatory capacities. Here, we describe two novel modes of torpor, a response usually associated with cold or resource bottlenecks, as...

Die folgenden Einträge sind im Rahmen einer Recherchereise entstanden, die von der Heinz-Kühn-Stiftung finanziert wurde. Anfang 2014 hatte in Madagaskar eine neue Regierung unter Hery Rajaonarimampianina die Macht übernommen. Das Ziel der Reise war es, auszuloten, ob und wie dieser politische Einschnitt einen Neuanfang für Bevölkerung und Natur dar...

Effective conservation actions require knowledge on the sensitivity of species to pollution and other anthropogenic stressors. Many of these stressors are endocrine disruptors (EDs) that can impair the hypothalamus–pituitary–thyroid axis and thus alter thyroid hormone (TH) levels with physiological consequences to wildlife. Due to their specific ha...

Open-flow respirometry is a common method to measure oxygen-uptake as a proxy of energy expenditure of organisms in real-time. Although most often used in the laboratory it has seen increasing application under field conditions. Air is drawn or pushed through a metabolic chamber or the nest with the animal, and the O2 depletion and/or CO2 accumulat...

Hibernation and daily torpor (heterothermy) allow endotherms to cope with demanding environmental conditions. The depth and duration of torpor bouts vary considerably between tropical and temperate climates, and tropical hibernators manage to cope with a wider spectrum of ambient temperature (Ta) regimes during heterothermy. As cycles in Ta can hav...

Environmental stress induced by natural and anthropogenic processes including climate change may threaten the productivity of species and persistence of populations. Ectotherms can potentially cope with stressful conditions such as extremes in temperature by exhibiting physiological plasticity. Amphibian larvae experiencing stressful environments d...

Mammalian heterotherms, species that employ short or long periods of torpor, are found in many different climatic regions. Although the underlying physiological mechanisms of heterothermy in species from lower latitudes (i.e., the tropics and southern hemisphere) appear analogous to those of temperate and arctic heterotherms, the ultimate triggers...

Environmental change exposes wildlife to a wide array of environmental stressors that arise from both anthropogenic and natural sources. Many environmental stressors with the ability to alter endocrine function are known as endocrine disruptors, which may impair the hypothalamus-pituitary-thyroid axis resulting in physiological consequences to wild...

Seasonal environmental changes can be challenging for animals because they are usually characterized by fluctuations in temperature, considerable decreases in food resources and, in tropical and subtropical regions, water availability. One response to less favorable conditions is migration, which is energetically costly and potentially dangerous. T...

With cities growing at a rapid pace, animal species must either retreat to patches of intact natural habitat or adapt to novel conditions in urban areas. While this disturbance causes most species to be in local decline, some show specific behavioural plasticity, facilitating success in a new habitat. The Eurasian red squirrel (Sciurus vulgaris) is...

Environmental variation induced by natural and anthropogenic processes including climate change may threaten species by causing environmental stress. Anuran larvae experiencing environmental stress may display altered thyroid hormone (TH) status with potential implications for physiological traits. Therefore, any capacity to adapt to environmental...

The energy budgets of animal species are closely linked to their ecology, and balancing energy expenditure with energy acquisition is key for survival. Changes in animals’ environments can be challenging, particularly for bats, which are small endotherms with large uninsulated flight membranes. Heterothermy is a powerful response used to cope with...

Chemical, physical and biological environmental stressors may affect the endocrine system, such as the thyroid hormone (TH) axis in larval amphibians with consequences for energy partitioning among development, growth and metabolism. We studied the effects of two TH level affecting compounds, exogenous l‐thyroxine (T4) and sodium perchlorate (SP),...

Energy expenditure and ambient temperature (Ta) are intrinsically linked through changes in an animal's metabolic rate. While the nature of this relationship is stable, the breadth of change in thermoregulatory cost varies with body size and physiological acclimatization to season. To explore seasonal metabolic changes of small mammals, we studied...

The physiological compensation of animals in changing environments through acclimatization has long been considered to be of minor importance in tropical ectotherms due to more stable climatic conditions compared to temperate regions. Contrasting this assumption are reports about a range of metabolic adjustments in tropical species, especially duri...

In our latitudes, we are familiar with mammals who spend the less hospitable season of the year in dens, but it has come as some surprise to discover that dwarf lemurs in the tropics do the same. New studies show that thanks to their special thermoregulation strategies, they can adapt even more flexibly to the climate, habitats and sleeping sites.

The spiny forest of South Madagascar is one of the driest and most unpredictable habitats in Africa. The small-bodied, nocturnal primate Lepilemur leucopus lives in this harsh habitat with high diurnal and seasonal changes in ambient temperature. In this study, we investigated seasonal adaptions in energy budgeting of L. leucopus, which allow it to...

Resting site selection can have important effects on the behaviour and fitness of organisms. The maintenance of optimal body temperatures (T b) when faced with environmental variables has often been attributed to either specific microhabitat rest site characteristics or to behavioural strategies. Among many small group-living endotherms, social the...

Physiological or behavioural adjustments are a prerequisite for ectotherms to cope with different thermal environments. One of the world's steepest environmental gradients in temperature and precipitation can be found in southeastern Madagascar. This unique gradient allowed us to study the compensation of thermal constraints in the heliothermic liz...

Torpor, the controlled depression of virtually all bodily function during scarce periods, was verified in primates under free-ranging conditions less than two decades ago. The large variety of different torpor patterns found both within and among closely related species is particularly remarkable. To help unravel the cause of these variable pattern...

During hibernation, critical physiological processes are downregulated and thermogenically induced arousals are presumably needed periodically to fulfil those physiological demands. Among the processes incompatible with a hypometabolic state is sleep. However, one hibernating primate, the dwarf lemur Cheirogaleus medius, experiences rapid eye movem...

Excel files (5) one per individual for which data were used C_crossleyi_Ly_database

Urban expansion and associated habitat fragmentation are expected to be detrimental to global biodiversity. Natural habitat that is extensively modified often poses challenges to native fauna that must adapt to new conditions to survive. While some species decline in numbers or become locally extinct, the Eurasian red squirrel (Sciurus vulgaris) su...

The dwarf and mouse lemurs of Madagascar are two very species-rich lemur genera, yet there is a relative paucity of information on this primate family in published literature. In this first ever treatment of the Cheirogaleidae, international experts are brought together to review and integrate our current knowledge of the behaviour, physiology, eco...

Increasing evidence shows that torpor in mammals is not only an effective adaptation for surviving predictable seasonal harsh conditions but is also employed as a response to acute emergency situations. This finding leads to the hypothesis that the ability to become heterothermic can also facilitate the colonization of new habitats, when mammals ha...

Dass nicht nur in unseren Breiten Säugetiere die unwirtliche Jahreszeit in Höhlen zubringen, sondern auch die Fettschwanzmakis in den Tropen — diese Entdeckung war eine echte Überraschung. Neue Studien zeigen, dass sich diese Lemurenart dank ihrer besonderen Thermoregulation sogar viel flexibler an klimatische Gegebenheiten, Habitate und Schlafplät...

In conclusion, our results show a close relationship and high accuracy between Tsk and Tb in lizards of different body sizes and thus a high applicability of both methods, ETLs and IRTs. Considerable differences between Tsk and Tb occurred only during phases of intense changes in Tb, and were detectable even in lizards with a BM of ~20 g, suggestin...

Mammals generally profit from social thermoregulation, and the primary benefit of sociality during hibernation is thought to be the reduction of metabolic demands during periodic arousals. It has even been postulated that the energetic advantages during hibernation might have been the driver for the evolution of sociality in some mammal species. As...

The reddish-gray mouse lemur (Microcebus griseorufus) is one of only a few small mammals inhabiting the spiny forest of southwestern Madagascar. In this study we investigated the physiological adjustments which allow these small primates to persist under the challenging climatic conditions of their habitat. To this end we measured energy expenditur...

Heterothermy is an energy-saving strategy usually employed in response to environmental bottlenecks, which is common in almost all mammalian orders. Within the order primates, heterothermy has been physiologically confirmed only in the family Cheirogaleidae (Cheirogaleus, Microcebus, Allocebus, Mirza) of the Malagasy lemurs, and the southern lesser...

The capacity for nonshivering thermogenesis (NST) plays an important role during arousal from torpid states. Recent data on heterotherms inhabiting warmer regions, however, suggest that passive rewarming reduces the need of metabolic heat production during arousal significantly, leading to the question: to what extent do subtropical or tropical het...

Hibernation in mammals is a remarkable state of heterothermy wherein metabolic rates are reduced, core body temperatures reach ambient levels, and key physiological functions are suspended. Typically, hibernation is observed in cold-adapted mammals, though it has also been documented in tropical species and even primates, such as the dwarf lemurs o...

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The European red squirrel Sciurus vulgaris inhabits areas which undergo profound seasonal declines in food availability and ambient temperature. We measured the body temperature (Tb) of free-ranging S. vulgaris over the course of one year to examine its thermoregulatory strategies and found no evidence of heterothermy, with Tb never dropping below...

Animals maximize fi tness by choosing their surroundings, including shelters for resting phases. Cheirogaleus medius is a small, nocturnal Malagasy lemur that hibernates in tree holes for up to 7 months a year. I compared certain characteristics of tree holes used during the active season with those used during the hibernation season to assess thei...

Little is known about strategies employed by small mammals to reduce energy expenditure during the summer. To understand whether ambient conditions impact euthermic energy demands in a small free-living hibernator, we measured metabolic rate of hazel dormice (Muscardinus avellanarius) in the field. Furthermore, we aimed to reveal which variables in...

The expression of heterothermy in the African lesser bushbaby, Galago moholi, seems to be strikingly different to most other heterotherms: G. moholi uses its ability to enter torpor only rarely and torpor is only used by a small fraction of the population. The aim of this study was, therefore, to summarize the parameters of torpor use in G. moholi...

The European rabbit Oryctolagus cuniculus is an important model system in the study of mammalian maternal behavior. This is at least partly due to the rabbit’s unusually limited pattern of maternal care, characterized by the mother briefly visiting the young to nurse just once approximately every 24 h. In studies of domestic breeds under laboratory...

), of free-ranging animals, particularly becauseseveral studies have shown that these parameters can differsubstantially between captive animals and their wild con-specifics (Geiser et al. 2007; Warnecke et al. 2007). Theseefforts were met by remarkable advancements in the minia-turization of data loggers, accommodating studies on small-bodied spec...

The three closely related primate species Cheirogaleus medius , Microcebus griseorufus , and Galago moholi employ a spectrum of thermoregulatory responses to environmental bottlenecks. C. medius is an obligate hibernator, M. griseorufus shows extreme flexibility in patterns of heterothermy, ranging from daily torpor to prolonged torpor and hibernat...

Climate change will not only directly affect climatic parameters, such as temperature and precipitation, but ultimately also ecological and physiological parameters of animal species. Our study investigates the effects of variation in climatic conditions, as experienced by climate change, on hibernation physiology and energy balance of a small hibe...

Behavioral and physiological adaptations are common and successful strategies used by small endothermic species to adjust to unfavorable seasons. Physiological adaptations, such as heterothermy, e.g., torpor, are usually thought to be more effective energy-saving strategies than behavioral adjustments. The African lesser bushbaby, Galago moholi, is...

The fat-tailed dwarf lemur, Cheirogaleus medius, occurs in ecologically very different habitat types (rainforest and dry forest) across Madagascar. Its extraordinary biological characteristics, such as monogamy and long-term hibernation, allow us to investigate behavioral, ecological, and physiological flexibility of this species in populations acr...

Flexibility in physiological processes is essential to adequately respond to changes in environmental conditions. Madagascar is a particularly challenging environment because climatic conditions seem less predictable than in comparative ecosystems in other parts of the world. We used the reddish-gray mouse lemur (Microcebus griseorufus) from the mo...

Hibernation and daily torpor are energy- and water-saving adaptations employed to survive unfavourable periods mostly in temperate and arctic environments, but also in tropical and arid climates. Heterothermy has been found in a number of mammalian orders, but within the primates so far it seems to be restricted to one family of Malagasy lemurs. As...

Several recent studies of animals in their natural surroundings found evidence for effects of certain major histocompatibility complex (MHC) immune gene alleles on the parasite load. However, in multi-infected individuals the particular selection pressure exerted by specific parasites has rarely been explored. In this study we took advantage of the...

Small endotherms must change roosting and thermoregulatory behaviour in response to changes in ambient conditions if they are to achieve positive energy balance. In social species, for example many bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, and also by social thermoregulation. Direct measurement...

Nocturnal primates and other mammals may not rely on alarm calls as an anti-preda-tor strategy (Rahlfs and Fichtel, 2010) because early detec-tion of predators at night is more difficult and solitary forag-ing may limit the usefulness of this strategy. The sportive lemurs however did alarm call in the presence of the snake. Alarm calls in nocturnal...

The spiny forest of southwestern Madagascar is the driest and most unpredictable region of the island. It is characterized by a pronounced seasonality with high fluctuations in ambient temperature, low availability of food, and a lack of water during the cool dry season and, additionally, by changes in environmental conditions between years. One of...

In this field study, the energetic properties of tropical hibernation were investigated by measuring oxygen consumption and body temperature of the Malagasy primate Cheirogaleus medius in their natural hibernacula. These lemurs use tree holes with extremely varying insulation capacities as hibernacula. In poorly insulated tree holes, tree hole temp...

Mate choice is one of the most important evolutionary mechanisms. Females can improve their fitness by selectively mating with certain males. We studied possible genetic benefits in the obligate pair-living fat-tailed dwarf lemur (Cheirogaleus medius) which maintains life-long pair bonds but has an extremely high rate of extra-pair paternity. Possi...

MOESM1 Fig. S1a Opened fruit of Strychnos madagascariensis, showing the arrangement of several seeds with closely attached pulp inside. b Fruit of S. madagascariensis being dispersed by the lemur Eulemur fulvus rufus. c Seed of S. madagascariensis being transported by several ants (Aphaenogaster swammerdami) into their nest

The objective of this study was to examine how the processes of seed dispersal and seed predation were altered in forest fragments of the dry forest of Madagascar, where the usual seed dispersers and vertebrate seed predators were absent, using a lemur-dispersed tree species (Strychnos madagascariensis; Loganiaceae) as an example. We then assessed...

The selection of suitable oviposition sites is crucial for successful reproduction of many organisms, including the endangered Madagascan frog Aglyptodactylus laticeps. In a preceding study, a conservation-oriented model of habitat use for this species extracted key habitat factors that reliably predict whether given ponds are used as oviposition s...

A crucial factor for the successful reproduction and thus conservation of most amphibian species is the availability of suitable waters as breeding sites. We examined the use of breeding sites of an endangered, locally endemic frog of Western Madagascar, Aglyptodactylus laticeps, over a three-year period. Logistic regression was used to model the r...

The frequency, species composition, and determinants of mixed‐species tadpole aggregations were analysed under natural conditions in a dry forest of western Madagascar. Most aggregations (73%) were formed by more than one species, with up to four species per individual aggregation. Dyscophus insularis (Microhylidae) and Aglyptodactylus securifer (M...

In the dry forest of western Madagascar, mixed-species social aggregations of tadpoles are frequent. Two species are often found in one aggregate. We explored the proximate mechanisms leading to the formation of tadpole aggregations that include the two species Aglyptodactylus securifer (Mantellidae) and Dyscophus insularis (Microhylidae). We show...

Current discussions in evolutionary ecology and conservation genetics focus on the relative importance of using selective neutral markers or markers of coding genes to identify adaptive and evolutionary relevant processes. Genetic diversity might be particularly important in immune genes (e.g., in genes of the major histocompatibility complex, MHC)...