Huisman–Olff–Fresco models

Huisman–Olff–Fresco models (HOF models) are a hierarchical set of 5 models with increasing complexity, designated for fitting unimodal species response curves{{cite web|title=SPECIES RESPONSE CURVES|author=Steven M. Holland|publisher=Department of Geology, University of Georgia, Athens, GA|url=http://strata.uga.edu/8370/handouts/SpeciesResponseCurves.pdf}} on environmental gradient.{{cite journal | last=Huisman | first=J. | last2=Olff | first2=H. | last3=Fresco | first3=L.F.M. | title=A hierarchical set of models for species response analysis | journal=Journal of Vegetation Science | publisher=Wiley | volume=4 | issue=1 | year=1993 | issn=1100-9233 | doi=10.2307/3235732 | pages=37–46|url=https://www.researchgate.net/profile/Han_Olff/publication/40209302_A_hierarchical_set_of_models_for_species_response_models._J_Veg_Sci_437-46/links/0deec523c1cac9e8ac000000.pdf}}

A implementation of the model including extension for bimodal distributions exists as an R module downloadable from CRAN.{{cite journal | last=Jansen | first=Florian | last2=Oksanen | first2=Jari | editor-last=Podani | editor-first=János | title=How to model species responses along ecological gradients - Huisman-Olff-Fresco models revisited | journal=Journal of Vegetation Science | publisher=Wiley | volume=24 | issue=6 | date=2013-02-07 | issn=1100-9233 | doi=10.1111/jvs.12050 | pages=1108–1117}}{{cite web | title=eHOF: Extended HOF (Huisman-Olff-Fresco) Models | website=CRAN | date=2020-05-22 | url=https://CRAN.R-project.org/package=eHOF | ref={{sfnref | CRAN | 2020}} | access-date=2021-04-30}}