Sampling strategies for the assessment of tree species diversity

Abstract

Abstract. This paper aims at proposing efficient vegetation sampling strategies. It describes how the estimation of species richness and diversity of moist evergreen forest is affected by (1) sampling design (simple random sampling, random cluster sampling, systematic cluster sampling, stratified cluster sampling); (2) choice of species richness estimators (number of observed species vs. non‐parametric estimators) and (3) choice of diversity index (Simpson vs. Shannon). Two sites are studied: a 28‐ha area situated in the Western Ghats of India and a 25‐ha area located at Pasoh in Peninsular Malaysia. The results show that: (1) whatever the sampling strategy, estimates of species richness depend on sample size in these very diverse forest ecosystems which contain many rare species; (2) Simpson's diversity index reaches a stable value at low sample sizes while Shannon's index is affected more by the addition of rare species with increasing sample size; (3) cluster sampling strategies provide a good compromise between cost and statistical efficiency; (4) 300 ‐ 400 sample trees grouped in small clusters (10–50 individuals) are enough to obtain unbiased and precise estimates of Simpson's index; (5) the local topography of the Western Ghats has a major influence on forest composition, the steep slopes being richer and more diverse than the ridges and gentle slopes; (6) stratified cluster sampling is thus an interesting alternative to systematic cluster sampling.

Tree diversity in western Kenya: using profiles to characterise richness and evenness

“…Magurran (1988) indicated that a Re´nyi series value with larger scale parameter value has reduced sensitivity to sample size. Gimaret-Carpentier et al (1998) observed that the Simpson index reached stable values at lower sample sizes compared to the Shannon index.…”

Dinâmica Populacional de Pulgão Preto dos Citros (Sternorrhyncha) em Cultivo Orgânico de Tangerina (Citrus reticulata Blanco) em Seropédica-RJ

“…A análise faunística do atendimento de formicídeos e dos predadores foi realizada através dos índices de riqueza (Jacknnife) (giMaret-carPentier et al 1998), diversidade (H') (Shannon-Wiener), Simpson (D), equitabilidade J (e) (Brower et al 1997) …”

Estimating change in species richness from repeated sampling of incidence data

“…It is known that the number of observed forest tree species in regional or national forest monitoring programs typically underestimates the actual number of forest species present in the sampled forests (Cao, et al, 2004;Chiarucci, et al, 2003;Gimaret-Carpentier, et al, 1998;Hellmann & Fowler, 1999;Hwang & Shen, 2010;Lam & Kleinn, 2008;Magnussen & Boudewyn, 2008). The exceptions are in forests with few relatively rare species and in the absence of rare forest tree species.…”

“…Estimating forest tree species richness from a forest inventory (monitoring) sample is a complex challenge with important issues related to temporal changes in the sample frame (Lister & Scott, 2009), sample size (Brose, Martinez, & Williams, 2003;Cao, et al, 2004;Hortal, Borges, & Gaspar, 2006), plot size (Brose, et al, 2003;Gimaret-Carpentier, Pelissier, Pascal, & Houllier, 1998;Shen & He, 2008), species identification (Archaux, 2009;Archaux et al, 2009), and choice of estimator (Mao & Lindsay, 2007;Walther & Morand, 1998). This study only deals with the last issue but fully recognizes that its importance depends critically on having satisfactory addressed all the other issues first.…”