Vertebrate Department
Carsten Rahbek

The overall aim of my current (and future) research program can be described as:
Patterns and determinants of
        • species distribution,
        • species range sizes,
        • composition of species assemblages, 
        • overall species richness
 as a response to
environmental (biotic and abiotic) factors
processes (contemporary and historical)
temporal and spatial scales


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Research program profile

My research program has been concerned with the use of vast quantitative databases on species
distribution (i.e., on faunistic data) to detect biogeographic patterns of species distribution, species
assemblages and species richness and explore what might determine such patterns. I have particular
looked at the interactions between animals and environmental factors – especially those linked to
contemporary productivity - whilesimultaneously consider the role and influence of history along
environmental gradients and in two-dimensional space across scale.

My approach is by testing the generality of various, diverging, hypotheses derived from studies
combining theory and experiment; by using a quantitative approach by compiling large faunistic
data sets, and by relating patterns of these attributes of species to the underlying spatial variation
of environmental and abiotic factors. The results obtained from these “natural” experiments are
compared with appropriate biological null models before the hypotheses involving biological
mechanisms are evaluated. Development of new analytical tools and approaches to seek “new”
ways to solve “old” problems is also a focus of my research.

My ongoing individual projects are currently centered on three major faunistic databases:

1. African vertebrates
One on the distribution of various vertebrate taxa of Africa compiled at the biogeographically and
for an entire continent fine spatial scale of 1 degree latitude-longitude: snakes (430 spp.; 34,889
records), amphibians (620 spp.; 29.750 records), mammals (960 spp.; 169,597 records), and
birds (1911 spp.; 604,318 records), including a corresponding reference database (in Papyrus) to
each of the above distributional databases.

2. South American birds
The distribution of South American birds (3100+ spp. with a total of 530,000 records – almost 1/3
of the species of birds in the world) compiled in the program WorldMap at the biogeographically
and for an entire continent fine spatial scale of 1 degree latitude-longitude; as well as
biogeographical and ecological databases on the same 3000+ spp. (50+ variables) in dBase IV

3. Danish fauna
A computerized database of available Danish atlas data compiled at an UTM grid with area
standardized to the fine spatial scale of 10 km x 10 km: 14 species of bats (Chiroptera), 18
species of amphibians/reptiles (Amphibia/Reptilia), 23 species of click beetles (Coleoptera:
Elateridae), 57 species of butterflies (Lepidoptera: Hesperioidea, Papilionoidea), 155 species of
large moths (Lepidoptera: Hepialoidea, Cossoidea, Zygaenoidea, Tineoidea, Yponomentoidea,
Bombycoidea, Geometroidea, Sphingoidea, Notodontoidea, Noctuoidea), and 167 species of
birds (Aves).

The two first databases on tropical vertebrates constitute perhaps the world’s largest biological databases
covering faunas of entire continents. The third, Danish database, represent faunistic Danish surveys that
are among the most detailed world wide, relative to the fine scale at which they are carried out.

Compared to my publication record, my current research program is in process of shifting focus from
solely tropical case studies to include even more use of Danish data and organisms. Thus, it is the plan
to enhance the effort and research use of the latter database on Danish faunistic data. This is to be
archived through active encouragement and collaborations with experts of other “new” taxa (e.g., the
recently started projects on all mammals of Hans Baagøe, ZMUC, on spiders of Nikolaj Scharff, ZMYC,
and others). These research plans should enhancing the use and application of the museums expertise
of the Danish fauna within taxonomy, collection and curation of specimens, which form the basis for
most of the faunistic data to be used within my future research agenda.

The below projects constitute my research program (arranged in no particular order of importance) within
analytical biogeography and quantitative faunistics. Listed hereafter is the other major focus of my research
agenda, which relates to conservation biology, where knowledge of evolutionary and biogeographical
principles and processes derived from my pure science projects is combined with research on how to
identify robust priorities for conservation. This research again focuses on use of vast quantitative
databases (some of the largest in existence) combined with rigorous testing of “unsupported” dogmas
and speculations, which conservation biology unfortunately is so inflated with.

Finally, I have listed two major projects that lie outside of the above main research agenda.

List of individual projects within my research program
1. Species assembly rules within Danish birds across temporal and spatial scales.
 Combining the following quantitative databases: the two Danish Atlases on breeding birds from 1971-1974
and 1993-1996 (in 5 x 5 km² quadrats), abundance estimates of individual species within most quadrates of
the 1993-1996 atlas, 25 years of point-count data throughout Denmark, a recent compiled GIS database that
has information on the spatial distribution of habitat in Denmark mapped at the resolution of 25 x 25 m² using
a classification-system of 10-12 habitat types, data sets on species composition of mixed-species flocks in
temperate and tropical forests, we intend to ask three questions: 1) What determines the spatial distribution
of species richness: is it random or deterministic abiotic factors such as contemporary climate,
landscape/habitat features, history; 2) assembly rules of mixed species flocks – are these random or do
forbidden combinations exist?; 3) what determines species assemblages  – are these random or do
forbidden combinations exist. The project aims at a re-evaluation of “Diamonds Assembly rules” using
comprehensive quantitative data sets and the application of more appropriate statistics and null models (i.e.,
“EcoSim”, developed by Nicholas Gotelli; and “Permute” developed by Legendre and co-workers) than those
applied by, e.g., Simberloff and Conner a decade ago.
 In collaboration with: Dr. Gary Graves (Smithsonian Institution) – some preliminary talks via Gary Graves
with Dr. Nicholas Gotelli (University of Vermont) concerning potential future collaboration (using his EcoSim).
 Duration: 2000-2003.

2. Development of a two-dimensional geometric constraints model (and software) to apply in
analyses of determinants of variation in species richness.
 Geographical patterns of species richness have been viewed and analyzed using the wrong null model for
150 years. “The challenge of developing fully analytical two- and three-dimensional geometric null models …
still remains” (Colwell & Lees 2000, TREE, vol. 15,  p. 74). In this project we developed a general null model
for species richness in irregular two-dimensional areas with hard boundaries using a Monte Carlo simulation.
Using distributional data on all breeding birds of Africa, we also demonstrate that patterns of richness are
predicted well from the modeled null effects alone, which call for more cautious analysis in the future of
species-richness patterns. A user-friendly software with the null model will be made publicly available in
association with publication of our results.
 In collaboration with: Walter Jetz (Oxford University)
 Duration: 1999-2002.

3. The effect of scale on perception and determinants of biogeographical/macro-ecological
 Scaling effects on species richness gradients are examined across spatial scales of two orders of
magnitude (ca. 12,300 to ca. 1,225,000 km²) using the clade of  hummingbirds as test taxa. Perception
of macro-ecological patterns is demonstrated to depend directly upon scale of analyses.  Using an
enormous database expanding the taxonomic coverage to include all 64 avian families of land and
freshwater birds that breed in South America, we investigate scale invariance of what determine
species richness. Analyses are based upon fine scale distributional maps (1o x 1o lat-long quadrats)
of 2,869 species, which provide the most accurate illustration of species richness patterns yet
produced for the immensely diverse South American avifauna (nearly one-third of the World's species).
A suite of 16 independent variables (n=16) permits unusually powerful tests of three major hypotheses
of species richness:1) contemporary climate model; 2) ecosystem diversity model; and the
3) latitude X topography model.  We compared the performance of the causal models with that of a
general ad hoc model (n=16 independent variables) at 10 spatial scales spanning two orders of
 In collaboration with: Dr. Gary Graves (Smithsonian Institute).
 Duration: 1995-2002.

4. Determinants of species richness, geographic range sizes, patterns of overlap and species’
ecology - an evolutionary perspective.
 Using a null model approach (i.e., see above) and the breeding distribution of all African birds and
mammals, we investigate determinants (using 16 abiotic parameters – mostly climatic) of species
richness, geographic range sizes dealing with the issue of spatial autocorrelation through use of
advance geospatial statistics. A biogeographical study of en entire continent.
 In collaboration with: Walter Jetz and Dr. Paul Harvey (Oxford University).
 Duration: 1999-2002.

5. Determinants of abundance, species assembly and species richness along an elevational gradient.
 The regional as well as local pattern of elevational gradient of species diversity will be statistically tested
against an appropriate null model (of geometric constraints on range placement), and then at the regional
scale against primary mechanisms such as productivity, climate, and available habitat area. Hereafter we will
evaluate the effect of secondary ecological mechanisms that are influential at local scales such as
interspecific competition and population dynamics in a source-sink equilibrium be evaluated.
 In collaboration with: A Ph.D. project of Tom Romdal, but also includes elaborate work with Dr. Robert
Colwell (Univ. of Conneticut).
 Duration: 1999-2001

6. An experimental investigation of control of migrational behavior of birds using Satellite telemetry.
 An experimental field study to investigate genetic effects involved in the control of bird migration. It is
planned to compare the movements of Danish and Finish populations of the Lesser Black-backed Gull
(different sub-species)  with different directions of migration (West and East Africa, respectively) by the
use of satellite telemetry. Furthermore, cross-foster and crossbred juveniles of these populations will be
tracked in order to study the importance of social behaviour and the mode of inheritance. The number of
satellite-tracked individuals (n=50) in this study is worldwide only matched by a US/Canadian project on
Peregrine Falcon.
 Collaborating institutions and P.I.s: Dr. Andreas Helbig (The Vogelwarte Hiddensee, University of
Germany); Dr. Pertti Saurola (the Zoological Museum, University of Helsinki, Finland); Dr. Carsten Rahbek
(the Zoological Museum, University of Copenhagen, Denmark).
 Duration: 2000-2001 (1999 was a pilot year with 6 adults satellite-tracked to Africa).

7. European Science Foundation Scientific Programme on "Optimality in Bird Migration".
 Migration varies among bird species, among populations, among age groups and among sexes, and
may even vary intraindividually. Within this program I plan to conduct research the next five years that
will explore the mechanisms and regulatory processes for understanding the role of migration within the
complete life cycle of a migrating species. Hereunder, the hope is to increase our understanding of how
natural selectionacts to mold migratory life-histories, and to elucidate the evolution of those life-histories.
The project will involve comparative and integrated studies, combining theory, field observations, and
laboratory studies, and linking, physics, physiology, ecology and behavior. It will be conducted in close
collaboration with the other partners of the program (see for
more details).
 Collaborating institutions and P.I.s: 16 different institutions from 13 different countries. Chairman is
Franz Bairlein (Institut für Vogelforschung, "Vogelwarte Helgoland", Wilhelmshaven, Germany),
Dr. Carsten Rahbek is member of the Steering Committee (and P.I. on behalf of the Danish Research'
 Duration: 2000-2004
 Funding: 16 different funding agencies through ESF.

8. A database of threatened European migratory passerines for investigating the effect of habitat
loss on migrational patterns and conservation priorities.
 To enhance the ecological study as well as the conservation of migratory birds, we propose to collect a
distributional database (mostly consisting of speciemens-based information) for all threatened European
migratory passerines migrating to Africa.  We will use this database to model each species' movement
across the African continent using geographic information system (GIS) analysis.  In the next step, GIS
will be used to define and map the essential stop-over sites and wintering habitats of each species.
Finally, we will analyze the effects of actual or potential habitat loss on the energetic budgets of migratory
 In collaboration with: A newly developed postdoctoral project in my lab with Dr. Bruno A. Walter.
 Duration: 2001-2002.
Funding: Postdoctoral scholarship for Bruno Walter obtained from the European Commission “Marie Curie
Individual Fellowship”.

9. The influence of behavioral flexibility on range sizes of species.
 Canopy and understorey species differ in their morphology, ecology and behavior. We hypothesize that
those species which show more flexible behavior and are therefore more prone to use widely and patchily
distributed resources over a larger area will also have larger range sizes than those species which show
more specialized behavior and are more prone to exploit reliable resources which are often defended within
a territory. This hypothesis is being tested using observational data from approximately 200 bird species,
using several comparative methods (across-species correlation, sister-taxa comparisons, PC-analysis).
 In collaboration with: Dr. Bruno A. Walter (ZMUC), and Dr. Monika Preleuthner & Dr. Hans Winkler (both
Konrad Lorenz-Institut für Vergleichende Verhaltensforschung, Vienna, Austria).
 Duration: 2000-2002.

10. Enhanced computerization and analysis of Bird Ringing Data – subproject: Variation over time
and space in survival of farmland birds.
 This EU project consists of several subprojects. They all focus on geospatial analyses of questions related
to movements and survival rates using all available European ringing and recovery data combined into one
database. The Danish subproject, with me as P.I., focuses on using ringing data to investigate variation in
survival of farmland birds over time and among regions of EU in relation to variation in farming practices.
 In collaboration with: 14 European institutions within EU. Headed by Professor van Noordwijk, Nederlands
Instituut voor Oecologisch Onderzoek – Populatiebiologie van Dieren.
 Duration: 2002-2005.
 Funding: EU-application pending

11. A null model to analyze dispersal and migration pattern of individuals accounting for the
influence of geometric constraints.
 Null models exclusively invoking geometric constraints have recently been demonstrated to be very
powerful in explaining geographic patterns of species richness. Analyses of migration and dispersal
patterns have traditionally been conducted in the absence of appropriate simulations and analytical
null models. This project is investigating the influence of shared physiographical and physiological
boundaries for terrestrial taxa, with ocean and sea as geometric constraints in relation to observed
patterns of migration when comparing the distribution of data modeled using a simple clock-and-
compass model with distributions of ringing recoveries.
 In collaboration with: Kasper Thorup (Institute of Population Biology, University of Copenhagen).
 Duration: 1999-2001.

12. The conditions of chicks of the Black-headed Gull in a declining population.
 The northern European population of Black-headed Gulls Larus ridibundus has de-clined in recent
decades for unknown reasons. Based on data on conditions of chicks for 12 Danish colonies, we
applied and enhanced a condition index of chick survival, based on the relationship between weight
and wing-length for rapid detection of relative breeding success among colonies. We also explored
its potential to produce an overall population model when combined such derived data on chick
condition with figures on fledging rate.
In collaboration with: Cand. scient. Henning Heldbjerg
 Duration: 1999-2001.

13. The EURING Swallow Project – a geospatial population study.
 This project focuses on a single species for which information is collected with standardized methods
in different environment, situations, countries and even continents. The main objectives of the project
are to 1) investigate bird populations under different environmental conditions, 2) investigate impact
of human activities on the environment through demographic parameters of populations, 3) investigate
impact of human activities on European migrants in their African winter quarters, and 4) describe main
migratory routes mapping geographical distribution of key staging areas for migrants within and outside
 Collaborating institutions and P.I.s: Institutions from 20 different European countries, USA, Japan and
South Africa. Chairman of project is Professor Fernando Spina (Instituto Nazionale Per la Fauna
Selatica, Italy). Dr. Carsten Rahbek is P.I. on the Danish participation, which includes 3 breeding
populations and 2 roosting sites during autumn migration.
 Duration: 1998-2003.
 Funding: Danish part “funded” by my research time. Data collection in field done with help of volunteer

14. Population trends, fluctuations and density-dependent regulation of short-, medium- and
long-distance migratory birds.
Using 20 years of breeding and migratory population indices from Denmark, Sweden, and Finland for 29
species, population fluctuations over time between migratory strategy are examined. Having annual indices
for both spring and autumn for the same population provided a mean for examining not only if
density-dependent regulation occurs, but also in which part of the yearly life cycle it may take place. To
analyze this, we developed and used a modified version of the randomization method of Pollard.
 In collaboration with: Associate Professor Jørgen Rabøl (Institute of Population Biology, University of
 Duration: 1999-2001.

 Conservation projects

15. Quantitative biological analyses of congruence in complementarity and of the efficiency of
Danish nature management – with emphasis on biological diversity.
 Similar in aim to that of the African project (# 15), but focusing on Denmark using all Danish atlas data
(bats, amphibians, birds reptiles, click beetles, butterflies and large moths mapped at the resolution of
10 x 10 km grids) available and working on a much finer spatial resolution. Associated with these
electronic databases are comparable data on habitat coverage of Denmark and landuse data, which
should provide a platform for seeking insight into the processes and mechanisms producing the pattern
obtained in the “traditional” priority-setting and congruence analyses. A first result of this project is an
evaluation of the efficiency of Danish management of biodiversity as part of the foundation for the last
Report of the Danish Economic Council (i.e., the “Økonomisk Råds Vismandsrapport”) on the same issue.
 In collaboration with: Cand. scient. Mette P. Lund (ZMUC)
 Duration: 1998-2001.
 Funding: From Novo Nordisk/WWF-Denmark to Mette P. Lund.

16. A continent-wide blueprint for conservation action in Africa: Conservation priorities integrating
multiple animal groups, human development and resource limitation.
 A unique data set (developed by Neil Burgess & Carsten Rahbek at ZMUC) on the complete distribution
of all African mammals, birds, snakes and amphibians (4000 spp. with >800,000 records) offers in
combination with the tools implemented in the software WorldMap (by Dr. Paul Williams) an extremely
exciting opportunity to pioneer a continent-wide blueprint for conservation action that addresses the
following questions: 1) To what extent are all species captured within the priorities generated using
different analytical approaches?; 2) To what extent do priority areas for one group capture species in
other groups?; 3) To what extent do the priorities generated cover the species most threatened with
extinction (IUCN Red Data Book species)?; 4) To what extent do the priorities generated by the World
Bank and conservation organizations (WWF, Conservation International, BirdLife International, etc.),
using other approaches (usually based on little hard distributional data), compare to those generated
using the principles of complementarity, and with results obtained from random selection of areas?;
5) To what extent do the priorities generated here compare in efficiency with the existing network of
protected areas?; 6) To what extent do the priorities generated capture species from different habitat
guilds, - i.e., how well do we cater for desert species as opposed to rainforest species?; 7) To what
extent can conflicts between conservation priorities and human-development issues be eased through
the identification of areas of low conflict and high conflict in Africa? (Projecthomepage:
Collaborating institutions and P.I.s: Dr. Andrew Balmford (Cambridge) and Dr. Carsten Rahbek are
the two P.I.s. Postdoctoral scientists: Dr. Thomas Brooks and Dr. Joslin L. Moore. Collaborating senior
scientists: Dr. Neil D. Burgess (WWF-US) and Dr. Paul Williams (the Biogeography and Conservation
Lab at British Museum). Other collaborating Institutions: Danida, Conservation International Foundation’s
Center for Applied Biodiversity Science, the Institute of Applied Ecology/Species Survival Commission
of IUCN, GEF Secretariat (GEFSEC) in Washington, D.C., the GEF Units in WorldBank, and the
GEF-Units in UNDP, New York.
Duration: 2000-2002.
 Funding: Ministry of Foreign Affairs, Danida, Department of Development Research. Isaac Newton Trust,
United Kingdom. Conservation International, Center for Applied Biodiversity Science.

17. Deductive modeling of area of occupancy of species from species’ range of extension.
 This project is a GIS-modeling expansion of the above project. The aim is to construct a detailed
database on the ecological attributes of all African vertebrates (4000 spp.). Using GIS-mapped
environmental data and the database with information on the habitat requirements (e.g., elevational
range, vegetation type) of any given taxon, we will explore the possibility to crosswalk (through
deductive distribution models) from the range extension depicted at 1 degree resolution (of the
above project) to a more precise deductive representation of area of occupancy of an individual
taxon, species assemblages, as well as overall species richness at very fine spatial scales (i.e.,
individual localities).
 Collaborating institutions: Dr. Andrew Balmford (Cambridge), Dr. Thomas Brooks (Conservation
International), Ph.D. student: Mary Wisz. Dr. Neil D. Burgess (WWF-US, BirdLife Denmark),
Dr. Paul Williams (the Biogeography and Conservation Lab at British Museum), and Prof. Luigi
Boitaani and Dr. Fabio Corsi (both Istituto di Ecologia Applicata, University of Rome). Other
collaborating Institutions: Danida, Conservation International Foundation’s Center for Applied
Biodiversity Science, the Institute of Applied Ecology/Species Survival Commission of IUCN,
and BirdLife International.
 Duration: 2000-2002.
 Funding: Conservation International, Center for Applied Biodiversity Science.

18. Assessing the usefulness of “flagship” and “umbrella” species for representing overall diversity.
 Conservationists and NGOs often base strategies for preserving biodiversity on the assumption that large
and charismatic species can act as efficient “ambassadors” for the rest of biodiversity. More than US $ 50
million are spent based on this assumption. Recently, the effectiveness of this approach was challenged in
a paper by Simberloff (1998, Biol. Conserv., Vol. 83:247-257), where he questioned whether that era was
not passé as no tests on suitable data had ever been conducted to support the approach. Applying the
vast quantitative database on the distribution of all Sub-Saharan African mammals (same data as in project
#  15), we provide a real test of Simberloff’s question. We found that the approach of using a small number
of mammalian flagship species in Africa was not better for representing the diversity of mammals and birds
than were groups of the same number of species chosen at random!
 In collaboration with: Dr. Paul Williams (the Biogeography and Conservation Lab at British Museum) and
Dr. Neil D. Burgess (WWF-US, BirdLife Denmark).
 Duration: 1998-2001.

 Other projects

19. Wildlife as a source of Salmonella infection in food animal production.
 The aim of this project is to generate knowledge about the occurrence of Salmonella in a number of
non-production animal species (wildlife, pet animals) geographically co-existing with animals herds
produced for human consumption. The studied wild animals include migratory bird species co-existing
during breeding and/or migration to production-animal herds. Focusing on yet insufficiently investigated
areas of spreading, killing, survival and growth of Salmonella in wildlife species in relation to infected
domestic animal herds and uninfected control herds enables analyses of the significance of wildlife
and pet animals as vectors of spread of Salmonella to the food-animal production. This in turn
contributes information necessary for a risk assessment of wildlife and pet animals as a source of
Salmonella in the food chain.
 Collaborating institutions and P.I.s: Dr. Dorthe Lau Baggesen Danish Veterinary Laboratory, Dr. Andrew
Spenser Danish Pest Infestation Laboratory, and Dr. Carsten Rahbek (ZMUC).
 Duration: 2000-2003.
 Funding: Ministry of Food, Agriculture and Fisheries – Danish Directorate for Development Research and
Development Department Research Secretariat.

20. Information campaign about ringing and its scientific use.
This project is aimed at the Danish public and intends to inform about the use, relevance and importance of
ringing as a scientific tool. It is also hoped that in addition to PR and traditional information campaign, it can
increase the return-rate of rings found by the public.
Duration: 2000-2002.
Funding: The Danish Outdoor Council (“FriluftsRådet”).

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 Last update: 04 september 2002