Zoologists frequently delimit their communities
by reference to plants or environmental factors. The most universal
classification of habits is that of Elton & Miller
(1954):
(i) Terrestrial system
Formations:
Formations:
-
Open-ground type — if any dominant plants, these not more
than 15 cm (6 in) high.
- Field
type—dominant life form coincides with field layer, usually
not more than 2 m in height.
- Scrub
type—dominant life form does not exceed a shrub layer, height
generally not over 7.6 m (25 ft).
- Woodland
type —trees dominant life form.
Vertical layers:
Subsoil and rock.
-
Topsoil.
- Ground
zone, including low-growing vegetation, less than 15 cm (6
in).
- Low
canopy —up to about 7.6 m (25 ft).
- High
canopy.
- Air
above vegetation.
(ii) Aquatic system.
Formation types: these are shown in table
below.
|
A:
Very
small
|
B
Small
|
C
Medium
|
D
Large
|
E
Very
large
|
1
Still
|
Tree
hole
|
Small
pond 20 m2
|
Pond
0.5 ha
|
Large
pool 50 ha
|
Lake
or sea
|
2
Slow
|
Trickle
Gutter
|
Ditch
Field dyke
|
Canal
River
bank
Water
|
|
|
3
Medium
|
Trickle
|
Lowland brook
|
Lowland river
|
Lowland large river
|
River
estuary
|
4
Fast
|
Spring
|
Upland
weir
Small
torrent stream
|
Large
torrent stream
|
|
|
5
Vertical
|
Water
drip
Pipe
outlet
|
Small
weir
Water-fall
|
Large
weir
Medium
water-fall
|
Large
water-fall
|
|
Vertical layer:
- Bottom,
light, dark zones, water mass, light and dark zones - free : water
not among vegetation
-
Submerged vegetation.
- Water
surface — upper and under surface of film of floating
leaves.
- Emergent
vegetation — reed swamp and similar vegetation, the bases of
which are in the water. Air above vegetation.
(iii) Aquatic
Terrestrial transition system - defined further
by body type with which it occurs and by vegetational systems
corresponding to the terrestrial system.
(iv) Subterranean system
Caves and underground waters.
(v) Domestic system.
(vi) General system
- Dying
and dead wood.
-
Macro-fungi.
-
Dung.
-
Carrion.
- Animal
artefacts — nests, etc.
- Human
artefacts — fence posts, straw stacks, etc.
Further division of the habitat into communities
may be made on the type of plant but in soil and freshwater
studies, divisions have been based on the fauna itself; these
techniques have been used in few other situations, but their use
could undoubtedly be extended.