Projects


The town mouse and the country mouse:

Individual, population and community responses to urban environments in small mammals

The main aim of this project is to understand drivers and limits of responses of small mammals to urban environments. Along a gradient from rural to urban environmental conditions in Brandenburg/Berlin (AgroScapeLabs and CityScapeLabs), involving changes in predation risk, (novel) food availability, anthropogenic disturbance, light and noise pollution, we empirically test for associated changes in risk-taking and exploration behaviour, behavioural flexibility, space use and immunology in four rodent species.

 

As part of a large network (BIBS), we further analyse key functional traits of successful rodent species that meet the challenges created by urban environments, the effects of urban environments on population genetic structure and density, as well as transitions in species composition of small mammal communities.

 

Funding: BMBF Project “Bridging in Biodiversity Science”

 

Collaborators: J. Eccard (UP), J. Fickel (IZW)

 

Students: V. Mazza (UP), A. Schirmer (UP),  M. Steffen (UP), J. Kunkel (UP), C. Göttsche (UP), T. Wendlandt (UP), C. Müller (UP)



Individual reaction norms and reversible plasticity in energy-saving strategies

This project aims to unravel the drivers and limits of individual variation and plasticity of energy-saving mechanisms in mammals to assess resilience of endothermic species to climatic change. The main approaches are field recordings of body temperature, respirometry to measure energy consumption, experimental manipulation of temperature (laboratory) and food availability (field and laboratory).

 

Studies involve two small mammal species facing very different predicted climatic changes: (i) the grey mouse lemur, (Microcebus murinus), under increased frequency of catastrophic weather events in the seasonal tropical dry deciduous forest in Madagascar and (ii) the eastern chipmunk (Tamias striatus) under gradual rise in ambient temperature in temperate seasonal forests. In both species we demonstrated among-individual differences in reaction norms, which had fitness consequences in eastern chipmunks, suggesting heritable differences in phenotypic plasticity among individuals.

 

Funding: DFG (DA 1377/2-1&2-2), Ethologische Gesellschaft, CNRS and MNHN Paris

 

Collaborators: P.-Y. Henry (CNRS, MNHN Paris, F), P. Vuarin (CNRS, MNHN, F), F. Aujard (CNRS, MNHN Paris, F), M. Humphries (McGill, CA), D. Réale (UQAM, CA)

 

Publications:
Dammhahn, M., Landry-Cuerrier, M., Réale, D., Garant, D. & Humphries, M.M. (2017) Individual variation in energy-saving heterothermy affects survival and reproductive success. Functional Ecology 31: 866–875.

 

Vuarin, P., Dammhahn, M., Kappeler, P.M. & P.Y. Henry (2015) When to initiate torpor use? Food availability times the transition to winter phenotype in a tropical heterotherm. Oecologia 179: 43–53.

 

Vuarin, P., Dammhahn, M., & Henry, P.-Y. (2013) Individual flexibility in energy saving: body size and condition constrain torpor use. Functional Ecology 27: 793-799.

 



Understanding rats’ invasion on Madagascar

Many ecosystems today are threatened by invasive species. These newcomers prey on or compete with native species, they carry new parasites and diseases and even cause extinctions of long-established residents. But why are some species such successful invaders and others advances in foreign territory remain unrecognized?

 

To answer this question, we focused on one of the most pervasive examples of invasive species: rats. Based on intensive field work in Madagascar and stable isotope analysis we demonstrated that an extremely broad and flexible generalist dietary niche is key to the invasion success of Rattus spp. and that individuals frequently move between anthropogenic habitats and natural forests.

 

Funding: UP, “StopRats” (European Union, European Development Fund) to S.M. Goodman   

 

Collaborators: Steven M. Goodman (Chicago Field Museum, Vahatra), T. Randriamoria (Antananarivo, MG)

 

Publications:

Dammhahn, M., Randriamoria, T.M. & Goodman, S.M. (2017) Niche differentiation using stable isotopes between invasive non-native Rattus spp. in anthropogenic and natural habitats of central eastern Madagascar. BMC Ecology 17:16.


Among-individual differences in movement equalizing/stabilizing species coexistence

Differential movement of individuals is a key mechanism generating spatial and temporal patterns of interacting individuals, populations and species and, thus, facilitating and maintaining biodiversity. 

 

In this project, we aim to test whether within-species trait variation in activity, exploration and risk-taking affects the local presence, density and spatial behaviour of individuals of coexisting small rodent species. By combining empirical, experimental and modelling approaches in two subsequent PhD projects, we aim to determine the potential effects of differential movement as stabilizing or equalizing mechanism for mediating species coexistence.

 

Funding: BioMove DFG-GRK 2118/1

 

Researchers: M. Dammhahn (UP), J. Eccard (UP), F. Jeltsch (UP), V. Grimm (iDIV), PhD cand. A. Schirmer (UP)



Individualised landscapes of fear

The mere presence of a predator creates a landscape of fear for prey. But do all individuals of the same population perceive the same landscape of fear? In this new project, I aim to test whether individual landscapes of fear exist, develop tools to quantify and compare them effectively, and test whether among-individual differences in perceived predation risk can be predicted by consistent behavioural differences. By closely interlinking experimental and spatially-explicit individual-based modelling approaches that increase stepwise in complexity from single foragers to small communities, I aim to start unravelling the consequences of individualised landscapes of risk on ecological interactions within and between species.

 

Funding: DFG DA 1377/4-1

 

Collaborators: F. Jeltsch (UP), J. Eccard (UP), V. Grimm (iDIV)


Personality and cognitive style

Individuals differ in how they acquire, process, store and act on information from the environment. Recently, it has been suggested that consistent among-individual differences in exploration and boldness, two common animal personality traits, should be linked with individual variation in cognitive styles, particularly along the speed-accuracy trade-off.

 

In several ongoing projects, we tested predictions of this hypothesis in a small primate, the grey mouse lemur (Microcebus murinus), two rodent species, the eastern chipmunk (Tamias striatus) and bank voles (Myodes glareolus), and a group-living bat (Carollia perspicillata). We found strong support for the functional integration of personality and cognitive styles via a risk-reward trade-off. Ongoing and future studies test fitness consequences of these individual differences in cognitive syndromes.

 

Funding: Various institutes (UP, UQAM, CNRS & MNHN, JKI)

 

Researchers: M. Dammhahn (UP), F. Aujard (CNRS and MNHN, F), D. Réale (UQAM, CA), J. Eccard (UP), J. Jacob (JKI), M. Knörnschild (FU), M. Zaccaroni (U Florence, I)

 

Students: PhD cand. V. Mazza (U Florence, I), M.Sc. F. Köhler (U. Göttingen), M.Sc. cand. A. Hardert (UP)

 

Publications:

Mazza, V., Jacob, J., Dammhahn, M., Zaccaroni, M. & Eccard, J.A. (under review) Individual variation in cognitive styles affects foraging and anti-predatory strategies in a small mammal.

 

Mazza, V., Eccard, J.A., Zaccaroni, M., Jacob, J. & Dammhahn, M. (2018) The fast and the flexible: cognitive style drives individual variation in cognition in a small mammal. Animal Behaviour 137: 119-132.


Functional biodiversity and coexistence mechanisms of mammal communities

One of my main scientific interests is to understand what determines high functional biodiversity in local mammal communities. Based on community ecology theory, I study coexistence mechanisms using field studies of feeding ecology and space use of exemplary sympatric congeneric species and stable isotopes analyses to illuminate niche differentiation across species-rich communities as well as within-species niche specialisation. Stable isotope analyses have the advantages of being based on non-invasively collected, time-integrating tissues (e.g. hair) and allow quantifying ecological niches of elusive species and of whole ecological communities. Ongoing current projects focus on feeding niche variation and invasion potential of Rattus spp. in Madagascar, functional biodiversity in mammal communities in Madagascar, coexistence mechanisms of small mammals along a rural-urban gradient in Germany, and intra-specific niche specialisation in eastern chipmunks in Canada.

 

Funding: Various sources; DFG, DPZ, Christian-Vogel Funds, Margot-Marsh Biodiversity Foundation

 

Collaborators: S. M. Goodman (Chicago Field Museum, USA), D. Réale (UQAM, CA), J. Eccard (UP)

 

Publications:

Dammhahn, M., Randriamoria, T.M. & Goodman, S.M. (2017) Niche differentiation using stable isotopes between invasive non-native Rattus spp. in anthropogenic and natural habitats of central eastern Madagascar. BMC Ecology 17:16.

 

Dammhahn, M., Rakotondramanana, C.F. & Goodman, S.M. (2015) Coexistence of morphologically similar bats (Family Vespertilionidae) on Madagascar: stable isotopes reveal fine-grained niche differentiation among cryptic species. Journal of Tropical Ecology 31:153-164.

 

Dammhahn, M., Goodman, S.M. (2014) Trophic niche differentiation and microhabitat utilization revealed by stable isotope analyses in a Malagasy dry forest bat community. Journal of Tropical Ecology 30: 9-109.

 

Dammhahn, M. & Kappeler, P.M. (2014) Stable isotope analyses reveal dense trophic species packing and clear niche differentiation in a Malagasy primate community. American Journal of Physical Anthropology, 153: 249-259.

 

Lührs, M.-L., Dammhahn, M., & Kappeler, P.M. (2013) Strength in numbers: males in a carnivore grow bigger when they associate and hunt cooperatively. Behavioural Ecology, 24: 21-28. (editors choice, with cover image).

 

Dammhahn, M., Soarimalala, V. & Goodman, S.M. (2013) Trophic niche differentiation and microhabitat utilization in a species-rich montane forest small mammal community of eastern Madagascar. Biotropica 45:111-118.

 

Dammhahn, M. & Kappeler, P.M. (2010) Scramble or contest competition over food in solitary foraging mouse lemurs (Microcebus spp.): new insights from stable isotope analyses. American Journal of Physical Anthropology 141: 181-189.

 

Lührs, M.-L., & Dammhahn, M. (2010) An unusual case of cooperative hunting in a solitary carnivore. Journal of Ethology 28: 379-383.

 

Dammhahn, M. & Kappeler, P.M. (2009) Females go where the food is: does the socio-ecological model explain variation in social organisation of solitary foragers? Behavioral Ecology and Sociobiology 63: 939-952.

 

Dammhahn, M. & Kappeler, P.M. (2008) Comparative feeding ecology of sympatric mouse lemurs (Microcebus berthae, M. murinus). International Journal of Primatology 29: 1567-1589.

 

Dammhahn, M. & Kappeler, P.M. (2008) Small-scale coexistence of two mouse lemur species (Microcebus berthae and M. murinus) within a homogeneous competitive environment. Oecologia 157: 473-483.