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Sample size requirements for in situ vegetation and substrate classifications in shallow, natural Nebraska Lakes

North American Journal of Fisheries Management

By:
, ,
DOI: 10.1577/1548-8675(2002)022<1329:SSRFIS>2.0.CO;2

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Abstract

We assessed the precision of visual estimates of vegetation and substrate along transects in 15 shallow, natural Nebraska lakes. Vegetation type (submergent or emergent), vegetation density (sparse, moderate, or dense), and substrate composition (percentage sand, muck, and clay; to the nearest 10%) were estimated at 25-70 sampling sites per lake by two independent observers. Observer agreement for vegetation type was 92%. Agreement ranged from 62.5% to 90.1% for substrate composition. Agreement was also high (72%) for vegetation density estimates. The relatively high agreement between estimates was likely attributable to the homogeneity of the lake habitats. Nearly 90% of the substrate sites were classified as 0% clay, and over 68% as either 0% or 100% sand. When habitats were homogeneous, less than 40 sampling sites per lake were required for 95% confidence that habitat composition was within 10% of the true mean, and over 100 sites were required when habitats were heterogeneous. Our results suggest that relatively high precision is attainable for vegetation and substrate mapping in shallow, natural lakes.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Sample size requirements for in situ vegetation and substrate classifications in shallow, natural Nebraska Lakes
Series title:
North American Journal of Fisheries Management
DOI:
10.1577/1548-8675(2002)022<1329:SSRFIS>2.0.CO;2
Volume
22
Issue:
4
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1329
Last page:
1333
Number of Pages:
5