Geoscience Reference
In-Depth Information
CHAPTER 13
Improvements in Understanding the
Contribution of Hyporheic Zones to
Biodiversity and Ecological
Functioning of UK Rivers
Paul J. Wood
1
, David J. Gilvear
2
, Nigel Willby
2
, Anne L. Robertson
3
,
Terence Gledhill
4
and Philip J. Boon
5
1
Department of Geography, Loughborough University, UK
2
School of Biological and Environmental Sciences, University of Stirling, UK
3
School of Human & Life Sciences, Roehampton University, UK
4
Freshwater Biological Association, Ambleside, UK
5
Scottish Natural Heritage, Edinburgh, UK
Introduction
2010). This reflects the increasing international
recognition of the contribution that the HZ makes
in supporting riverine biodiversity (Dole-Olivier
et al
., 2009), economically important fisheries
(Malcolm
et al
., 2010), pollution dispersal (Gandy
et al
., 2007) and the processing and transient
storage of nutrients essential for ecosystem
functioning (Mulholland and Webster, 2010). The
seminal paper on the ecology of the HZ by Traian
Orghidan was first published in 1953, subsequently
reproduced in German for a wider audience in
1959 (Orghidan, 1953, 1959) and has recently
been translated into English (Orghidan, 2010).
However, it was almost a decade before the wider
ramifications of this research were appreciated by
the scientific community as river ecologists began
exploring the vertical distribution of riverine fauna
within river beds in Europe (Schwoerbel, 1961).
Later in North America, the vertical distribution
of fauna was also examined (Coleman and Hynes,
1970)
The term 'hyporheic' literally means 'below' and
'flow' and is therefore out of sight and, until
relatively recently, has also been out of mind
for most stream ecologists and those engaged in
river conservation in the UK. Perhaps the best
and most widely used definition of the hyporheic
zone (HZ) is that of Boulton
et al
., (1998) who
defined it as an active ecotone between the river
flow and the underlying groundwater where water
flows through the substrate. However, other classic
physically based definitions concern the proportion
of river water and groundwater mixing, which
emphasize the spatial and temporally dynamic
nature of the HZ (Harvey and Bencala, 1993; Triska
et al
., 1993).
There has been a significant increase in the
amount of research centred on the HZ of rivers
of varying geology and flow regime in the last 20
years (Boulton
et al
., 2010; Robertson and Wood,
and
the
potential
role
of
the
HZ
as
a
