Do Lanice conchilega (sandmason) aggregations classify as reefs? Quantifying habitat modifying effects

Table 1 Biological characteristics as taken from different authors

	Intertidal Zühlke (2001)	Subtidal Van Hoey et al. (2008)	Subtidal Rabaut et al. (2007)
L. conchilega density (max ind m⁻²)	4,000	5,000	5,000
N0 (max)	10.5	29	35.6
N0/N0ref	1.2	2.4	2.8
N1	5.1	10
N1/N1ref	1.3	1.7
Abundance (max ind m⁻²)	72,000	4,500	8,000
Abund/Abund ref	2	9	5
ANOSIM	P < 0.001		R = 0.23, P < 0.001

In order to compare different values, only data related to biological reef characteristics were extracted from the publications. Only maximums are presented here to illustrate that differences occur for different regions (figures are indicative as they are presented as round numbers, deduced from published graphs). The effect of L. conchilega on the diversity indices (N0 total number of species; N1 exp(H’), with H’ the Shannon diversity) was calculated by taking the ratio of the biodiversity value when Lanice conchilega is present over the value in the same region when L. conchilega is absent (‘reference’, indicated as ‘ref’)

ISSN: 1438-3888