Environmental Engineering Reference
In-Depth Information
S. inundatum
P24
S. affine
P17
P2
F81
P40
S. palustre
c
en
P10
P51
S. angustifolium,
S. flavicomans,
S. magellanicum
s
ub
te
r
P52
P41
P21
avegwpH
aveswpH
F101
F103
P56
s
ut
P46
a
ff
iso
p
al
P11
P195
F10
F3
r
us
P6
F1A
f
le
avegwspc
P272
m
ic
ro
gir
in
u
le
s
F14
fal
age
F1
w
ar
F111
s
uf
P188
F108
ang
c
ap
P44
P4
2
P57
a
us
f
im
m
ag
P55
F104
P58
P45
v
ir
fl
a
P3
P59
t
or
p
ap
a
tl
P33
P50
P43
c
us
P31
Axis 2
Fig. 5.16 NMS ordination of wetlands (labeled P or F) within
Sphagnum
species space. Wetlands
were classified into four groups, named after group indicator species. Centroids of species
abundance are labeled by
crosses
, with the three-letter species abbreviation (e.g., cap
¼
S. capillifolium
).
Lines
are vectors of correlation with environmental variables;
longer lines
indicate stronger correlation. Micro
¼
microtopographic score, age
¼
time since most recent
beaver inhabitation, avegwpH and aveswpH are groundwater and surface water pH, respectively,
and avegwspc is mean groundwater specific conductivity
Exercise 5. Indicator Species
The table below contains data about the distribution of two species in degraded and
non-degraded wetlands. Given these data, which species would be a better indicator
of degradation and why?
Mean abundance in group/
Mean abundance overall
% of sites within group
in which species occurs
Degraded
Non-degraded
Degraded
Non-degraded
Typha angustifolia
0.92
0.08
100
10
Alnus incana
0.45
0.55
60
80
