WHEN TO QUIT? ESTIMATING SPIDER SPECIES RICHNESS IN A NORTHERN EUROPEAN DECIDUOUS FOREST

By N. Scharff, Jonathan Coddington, C. Griswold, G. Hormiga, Per de Place Bjørn. 2003

165 citations recorded by the source corpus.

Abstract Terrestrial arthropod surveys and inventories frequently suffer from undersampling bias; common species are over-represented and rare species may be missed entirely. This study compared a rapid (3 days) and intense inventory of spiders from one hectare of a mature beech forest (Fagus sylvaticus) in Hestehaven, Denmark, comprising 8,710 adult spiders of 66 species to a previous, much more thorough, bi-weekly survey of two years duration from the same site that comprised 42,273 spiders (adult and juvenile) of 141 species. Non-parametric species richness estimators were used to assess the degree of undersampling bias in various data partitions. The current study used five experienced, four novice collectors, and five semi-quantitative collecting methods. Method and time of day strongly affected numbers of species and adults per sample. Collector experience affected numbers of species but not numbers of adults per sample. Despite the intensive collecting, number of adults per sample did not decrease over the course of the study. At the end of the sampling, 31 species were still rare in the sample (singletons or doubletons). Non-parametric richness estimators suggest that the actual richness of adult spiders in the study plot at this time of year and susceptible to the methods used was about 80 species. Species turnover between the two surveys (ca 23 years) was remarkably small: the two lists were 92% identical. The base-line study suggests that the rarity of 12 of the 31 rare species was artifactual (10 due to phenology, one to method, another to spatial edge effects). The rarity of the remainder is unexplained and by default is interpreted as undersampling bias.

Subfields: Ecological Modeling, Insect Science, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/71f6ca184685482b3840e50f342a7139f29433ba

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Ecological Modeling

1. Pedro Cardoso
2. I. Silva
3. C. Gaspar
4. N. DE OLIVEIRA
5. A. Serrano
6. S. Henriques
7. N. Scharff
8. P. Borges

In Insect Science

1. Pedro Cardoso
2. I. Silva
3. C. Gaspar
4. N. DE OLIVEIRA
5. A. Serrano
6. S. Henriques
7. P. Borges

In Nature and Landscape Conservation

1. Pedro Cardoso
2. C. Gaspar
3. S. Henriques
4. N. Scharff
5. I. Silva
6. P. Borges
7. Pierre Legendre

Citations in the corpus

• Rapid biodiversity assessment of spiders (Araneae) using semi‐quantitative sampling: a case study in a Mediterranean forest (2008, methodology): “Scharff et al .”
• Seasonality of spiders (Araneae) in Mediterranean ecosystems and its implications in the optimum sampling period (2007, methodology): “Such methods are suitable for capturing a large number of species and simultaneously a large number of specimens with replicate samples ( Coddington et al. , 1996; Dobyns, 1997; Toti et al. , 2000; Sørensen et al. , 2002; Scharff et al. , 2003 ).”
• Standardization and optimization of arthropod inventories—the case of Iberian spiders (2009, methodology): “Sampling spiders in tropical (e.g., Coddington et al. 1991; Sørensen et al. 2002) or temperate forests (e.g., Coddington et al. 1996; Scharff et al. 2003) probably requires different methods and certainly different sample proportions.”
• Assessing spider species richness and composition in Mediterranean cork oak forests (2008, methodology): “Species richness is often found to be greater during the night (Green, 1999; Sørensen et al., 2002), but this seems to happen mainly in (sub-) tropical forests, and it is less likely to occur in temperate forests (Coddington et al., 1996; Dobyns, 1997; Green, 1999; Scharff et al., 2003).”