title: Linking habitat suitability to demography in a pond-breeding amphibian.
abstract: BACKGROUND
  Elucidating the relationship between habitat characteristics and population parameters is critical for effective conservation. Habitat suitability index (HSI) models are often used in wildlife management and conservation practice assuming that they predict species occurrence, abundance and demography. However, the relationship between vital rates such as survival and reproduction and habitat suitability has rarely been evaluated. In this study, we used pond occupancy and mark-recapture data to test whether HSI predicts occupancy, reproduction and survival probabilities. Our model species is the great crested newt (Triturus cristatus), a pond-breeding amphibian protected under the European Habitats Directive.
  
  
  RESULTS
  Our results show a positive relationship between the HSI and reproduction probability, whereas pond occupancy and survival probabilities were not related to HSI. Mortality was found to be higher during breeding seasons when newts are in ponds than during terrestrial phases of adult newts.
  
  
  CONCLUSIONS
  Habitat suitability models are increasingly applied to wildlife management and conservation practice. We found that the HSI model predicted reproduction probability, rather than occurrence or survival. If HSI models indicate breeding populations rather than mere species occurrences, they may be used to identify habitats of higher priority for conservation. Future HSI models might be improved through modelling breeding populations vs. non-breeding populations rather than presence/absence data. However, according to our results the most suitable habitat is not necessarily the habitat where demographic performance is best. We recommend that conservation practitioners should use HSI models cautiously because there may be no direct link between habitat suitability, demography and consequently, population viability.
authors.affiliation: Zoological Institute, Department of Evolutionary Biology, Unit Molecular Ecology, Technische Universität Braunschweig, Mendelssohnstraße 4, Braunschweig, 38106 Germany ; Department of Animal Ecology and Conservation, Biocentre Grindel, University of Hamburg, Martin-Luther-King Platz 3, Hamburg, 20146 Germany.
authors.forename: Bianca
authors.initials: B
authors.lastname: Unglaub
authors.affiliation: Zoological Institute, Department of Evolutionary Biology, Unit Molecular Ecology, Technische Universität Braunschweig, Mendelssohnstraße 4, Braunschweig, 38106 Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Steinfartz
authors.affiliation: Department of Animal Behaviour, Bielefeld University, Morgenbreede 45, Bielefeld, 33619 Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Drechsler
authors.affiliation: Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich, 8057 Switzerland ; KARCH, Passage Maximilien-de-Meuron 6, Neuchâtel, 2000 Switzerland.
authors.forename: Benedikt R
authors.initials: BR
authors.lastname: Schmidt
keywords: Environmental niche model; Habitat suitability index (HSI); Reproduction probability; Species distribution; Survival probability; Triturus cristatus