Geoscience Reference
In-Depth Information
improve understanding of how HZ communities
and individual taxa respond to nutrient loadings
and their role in nutrient processing and uptake.
Research in Scotland, where few data existed
previously, has begun to explore the ecology and
functioning of the HZ. This study has encompassed
sites from the north to the south, and both
hard metamorphic and igneous geologies and
soft rocks including the Durness limestone at
Inchnadamph. The vertical and spatial variation
in the composition and density of the hyporheos
at 25 sites distributed across Scotland has been
investigated, using a combination of Bou-Rouch
pumping and Karaman-Chappuis pits to sample
the interstitial fauna of exposed gravel bars
(Pryce
et al.,
2010). The faunal assemblage was
dominated by four major groups - oligochaetes,
cyclopoid copepods, nematodes and dipterans. In
total, 44 microcrustacean species were identified,
with
Microcyclops varicans
,
Bryocamptus pygmaeus
and
Bryocamptus zschokkei
the most abundant and
widely distributed. There was no evidence of a
specialist hypogean fauna at any site, even those
on limestone, consistent with the influence of
glacial legacy on distribution patterns (Strayer,
1994; Robertson
et al
., 2009).
Regional and national biodiversity
Contemporary HZ research in the UK has begun
to focus on regions of the country poorly explored
historically, including the English Peak District,
Yorkshire Dales and Lincolnshire. In addition, sites
in south-west England and some associated with
lowland chalk streams where benthic fauna have
been studied in the past are being re-examined
with specific consideration of the role of the HZ
(Stubbington
et al
., 2009). Research at present
covers a range of sites in England, Scotland and
Wales (Pryce
et al
., 2010; Wood
et al
., 2010; Schmid
and Schmid-Araya, 2010; Stubbington
et al
., 2011).
A summary of HZ biodiversity recorded at these
sites is given in Table 13.3. This clearly highlights
the greater biodiversity recorded in southern chalk
and limestone sites compared with northern sites
and those on non-karstic geology.
Table 13.3
Biodiversity of aquatic invertebrates recorded from sites/regions of the UK where examination of the
hyporheic zone has occurred during the last 5 years (2006-2010).
No.
Benthic
Taxa
b
No.
Benthic
Families
b
No.
Hyporheic
Taxa
c
No.
Hyporheic
Families
c
No.
Hypogean
Taxa
Total No.
Taxa
a
Total No.
Families
a
River
Little Stour (Kent)
*
107
52
104
52
68
39
5
R. West Glen (Lincolnshire)
*
75
52
75
52
43
39
0
R. East Glen (Lincolnshire)
*
64
49
64
49
45
37
1
R. Lathkill (Derbyshire)
*
69
50
69
50
53
42
1
R. Wharfe (North Yorkshire)
†
44
38
44
38
1
R. Wye (Derbyshire)
†
41
35
41
35
0
R. Exe (Devon)
†
38
32
38
32
5
R. Frome (Dorset)
†
44
35
44
38
0
R. Piddle (Dorset)
†
50
34
50
34
3
R. Rib (London)
†
56
32
56
32
4-5
R. Lee (London)
†
46
30
46
30
5
Scottish lowland (9 sites)
1
38 (30-46)
27 (22-32)
17 (11-20)
0
Scottish upland (5 sites)
1
34 (23-40)
23 (15-28)
18 (9-24)
0
Scottish montane (6 sites)
1
27 (22-31)
15 (10-19)
17 (14-20)
0
*
Studies did not identify meiofaunal groups beyond order,
†
Studies did not sample the benthos,
1
Mean per site with
range shown in brackets,
a
Total number of taxa from both benthic and hyporheic zone sampling,
b
Number of taxa
recorded in benthic samples,
c
Number of taxa recorded in hyporheic zone samples.
