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Citation
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HERO ID
4149744
Reference Type
Journal Article
Title
Development of an epiphyte indicator of nutrient enrichment: Threshold values for seagrass epiphyte load
Author(s)
Nelson, WG
Year
2017
Is Peer Reviewed?
Yes
Journal
Ecological Indicators
ISSN:
1470-160X
EISSN:
1872-7034
Volume
74
Page Numbers
343-356
DOI
10.1016/j.ecolind.2016.11.035
Web of Science Id
WOS:000398334500032
Abstract
Metrics of epiphyte load on macrophytes were evaluated for use as quantitative biological indicators for nutrient impacts in estuarine waters, based on review and analysis of the literature on epiphytes and macrophytes, primarily seagrasses, but including some brackish and freshwater rooted macrophyte species. An approach is presented that empirically derives threshold epiphyte loads which are likely to cause specified levels of decrease in macrophyte response metrics such as biomass, shoot density, percent cover, production and growth. Data from 36 studies of 10 macrophyte species were pooled to derive relationships between epiphyte load and.25 and 50% seagrass response levels, which are proposed as the primary basis for establishment of critical threshold values. Given multiple sources of variability in the response data, threshold ranges based on the range of values falling between the median and the 75th quantiles of observations at a given seagrass response level are proposed rather than single, critical point values. Four epiphyte load threshold categories low, moderate, high, very high, are proposed. Comparison of values of epiphyte loads associated with 25 and 50% reductions in light to macrophytes suggest that the threshold ranges are realistic both in terms of the principle mechanism of impact to macrophytes and in terms of the magnitude of resultant impacts expressed by the macrophytes. Some variability in response levels was observed among climate regions, and additional data collected with a standardized approach could help in the development of regionalized threshold ranges for the epiphyte load indicator. Published by Elsevier Ltd.
Keywords
Epiphyte; Nutrient indicator; Water quality indicator; Indicator development; Seagrass
Tag
NAAQS
•
ISA NOxSOxPM Ecology (2018)
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