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Informative plot sizes in presence-absence sampling of forest floor vegetation

Ståhl, Göran and Ekström, Magnus and Dahlgren, Jonas and Esseen, Per Anders and Grafström, Anton and Jonsson, Bengt Gunnar (2017). Informative plot sizes in presence-absence sampling of forest floor vegetation. Methods in ecology and evolution British Ecological Society. 8, 1284-1291
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Official URL: https://dx.doi.org/10.1111/2041-210X.12749

Abstract

Plant communities are attracting increased interest in connection with forest and landscape inventories due to society's interest in ecosystem services. However, the acquisition of accurate information about plant communities poses several methodological challenges. Here, we investigate the use of presence-absence sampling with the aim to monitor state and change in plant density. We study what plot sizes are informative, i.e. the estimators should have as high precision as possible.Plant occurrences were modelled through different Poisson processes and tests were developed for assessing the plausibility of the model assumptions. Optimum plot sizes were determined by minimizing the variance of the estimators. While state estimators of similar kind as ours have been proposed in previous studies, our tests and change estimation procedures are new.We found that the most informative plot size for state estimation is 1.6 divided by the plant density, i.e. if the true density is 1 plant per square metre the optimum plot size is 1.6 square metres. This is in accordance with previous findings. More importantly, the most informative plot size for change estimation was smaller and depended on the change patterns. We provide theoretical results as well as some empirical results based on data from the Swedish National Forest Inventory.Use of too small or too large plots resulted in poor precision of the density (and density change) estimators. As a consequence, a range of different plot sizes would be required for jointly monitoring both common and rare plants using presence-absence sampling in monitoring programmes.

Authors/Creators:Ståhl, Göran and Ekström, Magnus and Dahlgren, Jonas and Esseen, Per Anders and Grafström, Anton and Jonsson, Bengt Gunnar
Title:Informative plot sizes in presence-absence sampling of forest floor vegetation
Series/Journal:Methods in ecology and evolution British Ecological Society (BIB12310096)
Year of publishing :2017
Volume:8
Page range:1284-1291
Number of Pages:8
Publisher:British Ecological Society, Wiley
Associated Programs and Other Stakeholders:SLU - Environmental assessment > Programme Forest
ISSN:2041-210X
Language:English
Publication Type:Journal article
Refereed:Yes
Article category:Scientific peer reviewed
Version:Accepted version
Full Text Status:Public
Agris subject categories.:F Plant production > F40 Plant ecology
K Forestry > K01 Forestry - General aspects
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:forestry, plant ecology, density, vegetation, surveys
Keywords:density, intensity, optimum plot size, plant monitoring, point pattern, Poisson model, sample plots, vegetation change, vegetation survey
URN:NBN:urn:nbn:se:slu:epsilon-e-4594
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-4594
Additional ID:
Type of IDID
DOI10.1111/2041-210X.12749
Web of Science (WoS)000412858600012
ID Code:14802
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
Deposited By: SLUpub Connector
Deposited On:22 Jan 2018 13:09
Metadata Last Modified:11 Jan 2019 13:30

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