Sammanfattning

For timber production purposes, plot-based inventory methods, such as circular plot sampling, are widely used. For rare objects, however, other methods are likely to be more cost-efficient and, consequently, studies of alternative methods are needed. In line transect sampling, the surveyor walks through the forest along inventory lines, and when an object of interest is noticed, the perpendicular distance between the object and the line is measured. After the inventory, a probability-of-detection function is estimated. Thereby, unbiased estimates are obtained, although objects in the neighbourhood of the line are not always noticed. The method has, for example, been used for inventory of bird populations and should also be a useful method for acquiring data on rare forest objects of interest for nature conservation (e.g. individual plant and animal species, snags and logs). The shape of the (true) probability-of-detection function depends on, for example, sighting conditions and number of objects. The accuracy of the method depends, among other things, on how well this function can be estimated. If only a few objects are found in the inventory, the function is likely to be poorly estimated. In this study, some characteristics of the line transect sampling method were investigated by Monte-Carlo simulation. Effects of the number of objects found on the estimation of the probability-of-detection function and, consequently, the accuracy of the inventory method were investigated. Furthermore, the influence of the spatial distribution of the objects (Poisson or clustered distribution) was studied.

Publicerad i

Forestry Sciences
1998, Volym: 51, nummer: 18, sidor: 273-281
Titel: Assessment of Biodiversity for Improved Forest Planning : proceedings of the Conference on Assessment of Biodiversity for Improved Planning
ISBN: 978-0-7923-4872-6
Utgivare: Springer

Konferens

Conference on Assessment of Biodiversity for Improved Planning

SLU författare

• Lämås, Tomas

  • Institutionen för skoglig resurshushållning och geomatik, Sveriges lantbruksuniversitet
    

• Ståhl, Göran

  • Institutionen för skoglig resurshushållning och geomatik, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Skogsvetenskap


Publikationens identifierare

DOI: https://doi.org/10.1007/978-94-015-9006-8_26

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/41905