02765nas a2200301   4500008004100000245011300041210006900154260001200223300001200235490000700247520175100254653001602005653001702021653001102038653002302049653001602072653002102088653001102109653002402120653002202144653002502166653002402191653003602215653003102251653003502282100001802317856012802335       2005                        eng d00aA simple method to fit geometric series and broken stick models in community ecology and island biogeography0 asimple method to fit geometric series and broken stick models in  cNOV-DEC  a199-2050 v283 aSpecies abundance distributions are widely used in explaining natural communities. their natural evolution and the impacts of environmental disturbance. A commonly used approach is that of rank-abundance distributions. Favored, biologically founded models are the geometric series (GS) and the broken stick (BS) model. Comparing observed abundance distributions with those predicted by models is an extremely time-consuming task. Also, using goodness-of-fit tests for frequency distributions (like Chi-square or Kolmogorov-Smirnov tests) to compare observed with expected frequencies is problematic because the best way to calculate expected frequencies may be controversial. More important, the Chi-square test may prove if an observed distribution statistically differs from a model, but does not allow the investigator to choose among competing models from which the observed distribution does not differ. Both models can be easily tested by regression analysis. In GS, if a log scale is used for abundance, the species exactly fall along a straight line. The BS distribution shows tip as nearly linear when a log scale is used for the rank axis. Regression analysis is proposed here as a simpler and more efficient method to fit the GS and BS models. Also, regression analysis (1) does not suffer from assumptions related to Chi-square tests; (2) obviates the need to establish expected frequencies, and (3) offers the possibility to choose the best fit among competing models. A possible extension of abundance-rank analysis to species richness on islands is also proposed as a method to discriminate between relict and equilibrial models. Examples of application to field data are also presented. (c) 2005 Elsevier SAS. All rights reserved.10aassemblages10abroken stick10acurves10adiversity patterns10aexplanation10ageometric series10aGreece10aIsland Biogeography10aplant-communities10arank-abundance plots10aregression analysis10aspecies abundance distributions10aspecies abundance patterns10atenebrionid beetles Coleoptera1 aFattorini, S.  uhttps://icgf.myspecies.info/content/simple-method-fit-geometric-series-and-broken-stick-models-community-ecology-and-island