02667nas a2200277   4500008004100000020004600041245008600087210006900173260001100242300001100253490000800264520181000272653001502082653002802097653002502125653001202150653001702162653002302179653003302202653002302235653003102258653001802289100001102307700002002318856005102338       2011                        eng d  a1476-4687 (Electronic)0028-0836 (Linking)00aSpecies-area relationships always overestimate extinction rates from habitat loss0 aSpeciesarea relationships always overestimate extinction rates f  cMay 19  a368-710 v4733 a<p>Extinction from habitat loss is the signature conservation problem of the twenty-first century. Despite its importance, estimating extinction rates is still highly uncertain because no proven direct methods or reliable data exist for verifying extinctions. The most widely used indirect method is to estimate extinction rates by reversing the species-area accumulation curve, extrapolating backwards to smaller areas to calculate expected species loss. Estimates of extinction rates based on this method are almost always much higher than those actually observed. This discrepancy gave rise to the concept of an &#39;extinction debt&#39;, referring to species &#39;committed to extinction&#39; owing to habitat loss and reduced population size but not yet extinct during a non-equilibrium period. Here we show that the extinction debt as currently defined is largely a sampling artefact due to an unrecognized difference between the underlying sampling problems when constructing a species-area relationship (SAR) and when extrapolating species extinction from habitat loss. The key mathematical result is that the area required to remove the last individual of a species (extinction) is larger, almost always much larger, than the sample area needed to encounter the first individual of a species, irrespective of species distribution and spatial scale. We illustrate these results with data from a global network of large, mapped forest plots and ranges of passerine bird species in the continental USA; and we show that overestimation can be greater than 160%. Although we conclude that extinctions caused by habitat loss require greater loss of habitat than previously thought, our results must not lead to complacency about extinction due to habitat loss, which is a real and growing threat.</p>
10a*Ecosystem10a*Extinction, Biological10a*Models, Statistical10aAnimals10aBiodiversity10aModels, Biological10aPasseriformes/classification10aPopulation Density10aTrees/growth & development10aUnited States1 aHe, F.1 aHubbell, S., P.  uhttps://xianhuflora.myspecies.info/en/node/19602047nas a2200277   4500008004100000020004600041245006600087210006100153260000800214300001200222490000700234520124200241653002601483653001501509653001201524653001601536653001401552653005401566653002001620653001401640653001401654653002301668100001301691700001401704856005101718       2011                        eng d  a1558-5646 (Electronic)0014-3820 (Linking)00aThe tempo and mode of evolution: body sizes of island mammals0 atempo and mode of evolution body sizes of island mammals  cJul  a1927-340 v653 aThe tempo and mode of body size evolution on islands are believed to be well known. It is thought that body size evolves relatively quickly on islands toward the mammalian modal value, thus generating extreme cases of size evolution and the island rule. Here, we tested both theories in a phylogenetically explicit context, by using two different species-level mammalian phylogenetic hypotheses limited to sister clades dichotomizing into an exclusively insular and an exclusively mainland daughter nodes. Taken as a whole, mammals were found to show a largely punctuational mode of size evolution. We found that, accounting for this, and regardless of the phylogeny used, size evolution on islands is no faster than on the continents. We compared different selection regimes using a set of Ornstein-Uhlenbeck models to examine the effects of insularity of the mode of evolution. The models strongly supported clade-specific selection regimes. Under this regime, however, an evolutionary model allowing insular species to evolve differently from their mainland relatives performs worse than a model that ignores insularity as a factor. Thus, insular taxa do not experience statistically different selection from their mainland relatives.10a*Biological Evolution10a*Body Size10aAnimals10aEnvironment10aGeography10aMammals/genetics/growth & development/*physiology10aModels, Genetic10aPhenotype10aPhylogeny10aSelection, Genetic1 aRaia, P.1 aMeiri, S.  uhttps://xianhuflora.myspecies.info/en/node/198