@article{fdi:010063943,
  title = {{K}eystone species : toward an operational concept for marine biodiversity conservation},
  author = {{V}alls, {A}. and {C}oll, {M}arta and {C}hristensen, {V}.},
  editor = {},
  language = {{ENG}},
  abstract = {{V}arious definitions and indices have been proposed in the literature to identify keystone species. {I}n this study, we intended to make the concept of keystone species operational for marine biodiversity conservation. {W}e used an exclusive definition of keystone species, based on the original concept of keystone predator, and derived a new functional index of keystoneness ({KS}) from an ecosystem-modeling approach. {F}irst, several {KS} indices were formulated, by combining measures of the mixed-trophic impact ({MTI}) and biomass of species. {T}hen, a meta-analysis was performed, based on 101 published {E}copath food-web models, selected with a scoring method, and representative of the variety of marine ecosystems worldwide. {T}he indices were applied to the models, and two statistical methods were compared to select the most promising {KS} index. {R}ank correlation tests were performed to assess the balance between the contribution of the impact and biomass components to the different {KS} indices. {I}n addition, a classification tree was implemented, based on ecosystem-specific thresholds applied to the latter species traits, and used to confirm the identified keystone species. {T}he selected index obtained the highest number of models with positive results from both the rank correlation tests and the classification tree. {W}e also demonstrated the limitations of existing {KS} indices previously applied in the literature. {S}pecies were ranked according to their estimates of keystoneness with the selected {KS} index, so that potential keystone species were quantitatively identified in the 101 modeled food webs. {T}he standardized modeling approach allowed for a comparison of the identified keystone species across models: cartilaginous fishes and toothed whales obtained the highest occurrences. {F}inally, the selected {KS} index was applied to the well-known case study of {P}rince {W}illiam {S}ound ({A}laska, {USA}). {P}otentially significant anthropogenic (fishing) impacts on keystone species were also considered and discussed. {T}he operational methodology presented is directly applicable to marine food webs, and may be adapted to other (freshwater or terrestrial) systems.},
  keywords = {classification tree ; {E}copath model ; food-web structure ; index of keystoneness ; keystone species ; marine ecosystems ; meta-analysis ; mixed-trophic impact ; rank correlation tests ; scoring method},
  booktitle = {},
  journal = {{E}cological {M}onographs},
  volume = {85},
  numero = {1},
  pages = {29--47},
  ISSN = {0012-9615},
  year = {2015},
  DOI = {10.1890/14-0306.1.sm},
  URL = {https://www.documentation.ird.fr/hor/fdi:010063943},
}