Biodiversity and Conservation

, Volume 19, Issue 9, pp 2469–2484 | Cite as

Assessing the completeness of bryophytes inventories: an oceanic island as a case study (Terceira, Azorean archipelago)

  • Silvia C. ArandaEmail author
  • Rosalina Gabriel
  • Paulo A. V. Borges
  • Jorge M. Lobo
Original Paper


How useful, complete or unbiased are comprehensive databases in order to provide reliable estimations of diversity? Using compiled data from bryophytes in Terceira Island (Azores), we specifically aim (1) to describe the register of species over time, (2) to assess the inventory completeness, i.e., the ratio between the observed and the maximum expected species, and (3) to locate the most promising areas for further surveys. First, each new recorded species was plotted against its collecting year, using the number of database-records as a surrogate of survey effort, to get the accumulation curves. These curves were then extrapolated to obtain the theoretical number of existing species according to Clench and exponential models. Spatial and habitat characteristics of the recorded taxa were also explored. Our results show an increasing trend in the rate of recorded species (c. five species per year), as well as a maximum of around a third of the theoretically “real” number of expected species that could yet remain unknown. Nevertheless, predictions of species richness were highly variable depending on the fitting curve used. Survey effort was similar between liverworts and mosses, as were inventory completeness values, but the rate of new recorded species was higher for mosses. Although bryologists visited preferably native habitats, we show that new species citations may also be found in modified habitats (e.g., exotic forests and semi-natural grasslands). We conclude that the analysis of extensive databases is a useful tool in revealing the recording and taxonomic gaps, further showing that bryophyte inventories could still be incomplete in Terceira Island. A strategy on how to improve species’ collections in remote areas is suggested, hoping to contribute to all-inclusive biodiversity studies in the Azores and elsewhere.


Biological databases Collecting bias Laurisilva Liverworts Macaronesia Mosses Sampling efficiency Species accumulation curves 



We are very grateful to Berta Martins and Enésima Mendonça for their unconditional help with the ATLANTIS software. Thanks also to Fernando Pereira, who interpreted and placed most of collecting localities from old studies. SA is a PhD candidate from University of Azores and was supported by a grant from Direcção Regional da Ciência e Tecnologia dos Açores (M311/I009A/2005). PAVB and RG worked on this project under the DRCT projects M2.1.2/I/017/2007, M.2.1.2/I/003/2008 and the EU projects INTERREGIII B “ATLÂNTICO” (2004–2006) and BIONATURA (2006–2008).

Supplementary material

10531_2010_9854_MOESM1_ESM.doc (151 kb)
Supplementary material 1 (DOC 151 kb)
10531_2010_9854_MOESM2_ESM.doc (63 kb)
Supplementary material 2 (DOC 63 kb)


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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Silvia C. Aranda
    • 1
    • 2
    Email author
  • Rosalina Gabriel
    • 1
  • Paulo A. V. Borges
    • 1
  • Jorge M. Lobo
    • 2
  1. 1.Azorean Biodiversity Group—CITA-A, Departamento Ciências AgráriasUniversidade dos AçoresAngra do HeroísmoPortugal
  2. 2.Departamento de Biodiversidad y Biología EvolutivaMuseo Nacional de Ciencias Naturales (CSIC)MadridSpain

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