Effect of species richness and relative abundance on the shape of the species accumulation curve

• Published in: Austral ecology Vol. 28; no. 4; pp. 355 - 360
• Main Authors: Thompson, Graham G, Withers, Philip C
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Pty 01.08.2003; Blackwell
• Subjects: abundance; Animal, plant and microbial ecology; Biological and medical sciences; diversity; fauna survey; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Methods and techniques (sampling, tagging, trapping, modelling...); pit-trapping; rarity; reptiles; richness; species accumulation; Vertebrata; Pitfall trap; Fauna; Index; Reptilia; Biodiversity; Forecast model; Species richness; Ecological abundance; Rare species
• ISSN: 1442-9985; 1442-9993
• DOI: 10.1046/j.1442-9993.2003.01294.x

Abstract We explain how species accumulation curves are influenced by species richness (total number of species), relative abundance and diversity using computer-generated simulations. Species richness defines the boundary of the horizontal asymptote value for a species accumulation curve, and the shape of the curve is influenced by both relative abundance and diversity. Simulations with a high proportion of rare species and a few abundant species have a species accumulation curve with a low ‘shoulder' (inflection point on the ordinate axis) and a long upward slope to the asymptote. Simulations with a high proportion of relatively abundant species have a steeply rising initial slope to the species accumulation curve and plateau early. Diversity (as measured by Simpson's and Shannon-Weaver indices) for simulations is positively correlated with the initial slope of the species accumulation curve. Species accumulation curves cross when one simulation has a high proportion of both rare and abundant species compared with another that has a more even distribution of abundance among species.