Assessing biodiversity with species accumulation curves; inventories of small reptiles by pit‐trapping in Western Australia

Abstract

We examined 11 non-linear regression models to determine which of them best fitted curvilinear species accumulation curves based on pit-trapping data for reptiles in a range of heterogeneous and homogenous sites in mesic, semi-arid and arid regions of Western Australia. A well-defined plateau in a species accumulation curve is required for any of the models accurately to estimate species richness. Two different measures of effort (pit-trapping days and number of individuals caught) were used to determine if the measure of effort influenced the choice of the best model(s). We used species accumulation curves to predict species richness, determined the trapping effort required to catch a nominated percentage (e.g. 95%) of the predicted number of species in an area, and examined the relationship between species accumulation curves with diversity and rarity. Species richness, diversity and the proportion of rare species in a community influenced the shape of species accumulation curves. The Beta-P model provided the best overall fit (highest r 2 ) for heterogeneous and homogeneous sites. For heterogeneous sites, Hill, Rational, Clench, Exponential and Weibull models were the next best. For homogeneous habitats, Hill, Weibull and Chapman-Richards were the next best models. There was very little difference between Beta-P and Hill models in fitting the data to accumulation curves, although the Hill model generally over-estimated species richness. Most models worked equally well for both measures of trapping effort. Because the number of individuals caught was influenced by both pit-trapping effort and the abundance of individuals, both measures of effort must be considered if species accumulation curves are to be used as a planning tool. Trapping effort to catch a nominated percentage of the total predicted species in homogeneous and heterogeneous habitats varied among sites, but even for only 75% of the predicted number of species it was generally much higher than the typical effort currently being used for terrestrial vertebrate fauna surveys in Australia. It was not possible to provide a general indication of the effort required to predict species richness for a site, or to capture a nominated proportion of species at a site, because species accumulation curves are heavily influenced by the characteristics of particular sites.

Herpetofauna of Paranapiacaba: expanding our knowledge on a historical region in the Atlantic forest of southeastern Brazil

“…Relative abundance was calculated exclusively based on data collected by pitfall traps. Efficiency of the sampling method was evaluated using species rarefaction curves (COLWELL & CODDINGTON 1994, GOTELLI & COLWELL 2001, THOMPSON et al 2003, with 95% confidence interval and 1000 aleatorizations, using the software EstimateS 8.20 (COLWELL 2009). Richness was assessed through a non-parametric first order Jackknife index (HELTSCHE & FORRESTER 1983, HELLMANN & FOWLER 1999.…”

Estimating relative abundance and species richness from video surveys of reef fishes

“…First, occupancy or N-mixture modeling approaches can estimate detection or capture probabilities separately from the underlying distribution or abundance of a species (MacKenzie et al, 2002;Royle, 2004), but multiple site visits may be necessary each year (Issaris et al, 2012) unless spatial autocorrelation is modeled (Johnson et al, 2013). Second, if the emphasis is on es-timation of species richness over an entire study area, species accumulation (i.e., rarefaction) curves may be a useful approach (e.g., Nichols et al, 1998;Thompson et al, 2003). Species accumulation curves and related approaches (Angermeier and Smogor, 1995) may be especially useful in diverse systems with many rare species (Green and Young, 1993;Gotelli and Colwell, 2001).…”

Taxocenose de serpentes no Planalto Médio do Rio Grande do Sul, Brasil

“…O mesmo espécies (THOMPSON et al 2003). A dificuldade de atingir a assíntota, no presente estudo, se deve ao tempo limitado de coleta e às limitações impostas pelos métodos utilizados, além do fato de serpentes apresentarem um número relativamente baixo de capturas.…”

“…Curvas assintóticas assumem número finito de espécies capturáveis em uma determinada área, e quando esforço suficiente é aplicado, esse número de espécies poderia ser capturado (THOMPSON et al 2003 …”