Research Group 1: Evolutionary Ecology

Physiological strategies of food consumption and food processing

Availability, assimilation and allocation of food and/or energy is of vital importance for several aspects of the biology and life-history of animals, e.g. colonization of extreme habitats and niche separation, population dynamics and social systems, activity and habitat use, growth and reproduction. We investigate physiological strategies and behavioural adaptations of food ecology and energy allocation in mammals from Europe, Africa and Central America.  

The European roe deer (Capreolus capreolus) in particular serves as a model-species and is investigated with respect to its feeding ecology, energy allocation and physiology (digestion physiology and energy requirements) in the field research station of the IZW as well as in the field.

Project:

Energy allocation of European roe deer

Population dynamic and resource allocation of wild roe deer in Bialowieza National Park (Poland)

Digestion physiology of ruminating and non-ruminating foregut-fermenters

Feeding ecology of Apes

Nutrition Lab

Energy allocation of European roe deer

Sylvia Albrecht, Frank Göritz and Sylvia Ortmann

The aim of this interdisciplinary  project is to study strategies of adaptation of roe deer to their habitat, in particular to seasonal changes of nutrient availability. This project combines studies of metabolic and reproductive physiology and is performed by biologists and veterinarians of all five research groups in our field research station in a semi-natural environment.

Roe deer (Capreolus capreolus) are extremely successful and occupy almost all natural habitats in Europe, including deciduous and coniferous forests, shrub lands, moor lands and cultivated land. Only the open grassland and mountain pasture above the tree line is avoided because of lack of cover. Roe deer are medium-sized ruminants; their maintenance costs are high due to their small body size and unfavourable volume/surface ratio. Although they are generalist herbivores, they are very selective browsers and rely on high quality food.

Roe deer are seasonal breeders with a short rut in July/August. Following a diapause, i.e. a period of delayed implantation of the blastocysts from August to late December, 2-3 fawns are born in May or June. Roe deer are the only Artiodactyls exhibiting delayed implantation as a reproductive strategy, which enables them to adjust maternal investment into number and quality of fawns to food availability. Thus the roe deer is an excellent model to study energy allocation and trade-offs between traits such as reproduction, maintenance or immune function.

We perform feeding experiments with roe deer in our field research station in Niederfinow under semi-natural conditions to investigate:

• by which priority energy is allocated to competing traits like maintenance, reproduction and immune function, when energy is limited,
• which tactics are used by roe deer to reduce energy costs (activity, energy expenditure),
• if, and when to which extend roe deer increase digestion efficiency to counterbalance or to reduce the effect of limited food supply (digestion physiology),
• the effect of energy restriction on reproduction output (fertility of bucks and does, litter size, quality of fawns)
• if, and at what level (ovulation, implantation, reabsorption) roe deer adjust litter size to food supply

Wir untersuchen Rehe, die in der Feldforschungsstation in Niederfinow unter naturnahen Bedingungen gehaltenen werden und erfassen das Verhalten, die Hormone, Wärmeabgabe, Verdauungseffizienz und Reproduktionsparameter (Abbildung 2).

Cooperation: Dr. C. Metges, Forschungsinstitut für Landwirtschaftliche Nutztiere, Dummerstorf; Prof. Dr. H. Sauerwein, Rheinische Friedrich-Wilhelms-Universität, Bonn

Population dynamic and resource allocation of wild roe deer in Bialowieza National Park (Poland)

Anne Berger and Sylvia Ortmann

In cooperation with the Mammal Research Institute (MRI) of the Polish Academy of Science (Wlodzimierz Jedrzejewski) we investigate the effect of habitat quality and predation pressure on condition, habitat use and reproduction output of wild European roe deer (Capreolus capreolus) in Bialowieza National Park (Poland).

At three study areas (closed forest, ecotone, open field) differing in food quality, food availability and predation pressure and at four seasons we record:

Plant biomass and plant quality, diet composition, body condition of roe deer (does), population density and population dynamics, habitat use, predation pressure.

Digestion physiology of ruminating and non-ruminating foregut-fermenters

Angela Schwarm and Sylvia Ortmann

Herbivores are divided into foregut and and hindgut-fermenters, depending on the anatomical position of the fermentation chamber. Among foregut-fermenters ruminators and non-ruminators can be distinguished. The herbivorous feeding-style and fibre-rich plants in particular rise the problem how to process big food-particles which are bulky and characterized by an unfavourable surface-volume-ratio. Several morphological and physiological adaptations have been evolved to cope with this problem. Ruminators e.g. submit big particles to repeated chewing and break them down. Hindgut-fermenters selectively excrete big particles and retain small particles. In this project we investigate whether non ruminating foregut-fermenters excrete big particles as fast as or faster than small particles, and are therefore despite their anatomical similarities with ruminators physiologically comparable to hindgut-fermenters   

Financial support: DFG (OR 86/1-1), NaFöG-Stipendium der Freien Universität Berlin

Cooperations: Abteilung für Zoo-, Heim- und Wildtiere, Vetsuisse-Fakultät, Universität Zürich, Schweiz; Hahn-Meitner Institut (HMI), Berlin; Zoologischer Garten, Berlin; Zoologischer Garten, Halle; Zoologischer Garten, Krefeld; Wilhelma, Stuttgart; Whipsnade Wild Animal Park, UK

Feeding ecology of Apes

Sylvia Ortmann

In a comparative and interdisciplinary approach we investigate the impact of feeding ecology and habitat quality on the distribution of several Ape species (bonobo, gorilla, chimpanzee), their co-existence, and the pattern and variability of their social systems. This is the first study in which data from different study areas all over Africa are collected using the same sampling protocol (Ivory coast, Nigeria, Democratic Republic of the Kongo, Uganda). The study is coordinated by Gottfried Hohmann from the Max-Planck-Institute of Evolutionary Anthropology in Leipzig and all plant and faeces samples are analysed at the nutritional lab of the IZW. In addition to food availability, food quality (macronutrients, plant secondary compounds) and diet composition, we investigate the significance of animal prey, party size and behavioural ecology.

Nutritional Lab

Heidrun Barleben and Sylvia Ortmann

The nutritional Lab runs standard methods of macronutrient analysis of plant and faeces samples, diet composition mineral analysis.

Nutrient analysis:
Crude protein, crude fat, carbohydrates (starch, glucose, fructose, sucrose), fibre analysis after Van Soest, energy

Diet composition:
Faeces analysis (inspection), analysis of n-Alkanes (GC), particle size i.e. modulus of fineness (wet sieving)

Mineral analysis:
Co and Cr e.g. as marker for digesta passage time, Mg, Fe, Ca, Cu (Atom-Absorption-Spectroscopy)

Miscellaneous:
Tannin-Binding-Assay
Fatty acids