In this course you will gain a greater understanding of all of the aspects involved in nature park management, including ecology, soils, plants and nature park design.
Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.
Where large areas of indigenous vegetation have been cleared for
housing, agriculture, industry, and other uses, they hence greatly
reduce habitat left for native wildlife. Many of these native vegetation
fragments are often small and isolated from one another by barriers
such as open pasture, housing, roads, and water bodies (e.g. dams).
These are sometimes known as "island" habitats. The size of an island
habitat greatly determines the likely success or otherwise of the
species that reside there. Genetic pools are restricted within a small
habitat that can lead to problems of diversity within a species. Larger
animals, especially predators are known to be severely impacted upon
when habitats shrink.
Predators play a major role in the overall health of an ecological
system. They tend to prey upon sick and weak animals thereby enforcing
evolutionary principles of survival of the fittest. This results in
healthy populations among the creatures that they do prey upon. Wildlife
corridors when properly maintained enable movement for animals between
habitats. This means that the habitat is not isolated and the problems
talked of earlier are not as prevalent.
Wildlife constantly moves:
Looking for food; new sources; seasonal availability
In island habitats there may be no adjacent habitat to forage in, or to disperse along.
Island communities
Situating Corridors
They may exist anywhere between habitat islands of any size, even as
little as a few old remnant trees that may provide valuable hollows, or
linking smaller patches to perhaps a larger state forest.
Remnant wetland environments (e.g. marshes, swamps, lakes) can also be
linked with other vegetation corridors, providing improved access for
wildlife to important water sources.
They are best designed where possible to follow natural contours (e.g.
rivers, ridges). They might incorporate other plantings (e.g.
windbreaks, timber lots).
Types of Corridors
1. Natural - follow natural contours (e.g. ridges, streams, gullies).
2. Remnant - along roadsides, railway reserves, disused stock routes and often follow straight lines.
3. Planted - such things as farm shelter breaks and windbreaks they are
generally created for other purposes than creating wildlife habitat, but
can serve a dual purpose.
Design Considerations
Preserve or restore natural corridors (e.g. gully lines, stream banks).
Stream sides are high value areas for wildlife. Limit stock access to
riverbanks to prevent erosion and allow for regeneration of riverside
vegetation.
Wherever possible build onto or restore existing corridors as they will
have existing populations of local flora and fauna, increasing the rate
of species spread.
The wider the corridor the better (e.g. at least 30 - 100 m wide) - see section on ‘edge effects’.
Corridors are more effective when they link up with large larger habitats with few or no gaps (e.g. roads cutting through).
Use local (indigenous) plants. These are adapted to local conditions
(e.g. soil, climate, fire regimes), and fauna are adapted to them. This
also preserves the biodiversity of local flora. They generally have low
establishment costs in comparison to introduced species. They have
minimal weed potential.
Incorporate all forms of vegetation (e.g. shrubs, grasses, rushes,
groundcovers, climbers), not just trees. For example grassy forests may
have four different large tree species and between 70 and 100 under
storey species. This means that the under storey represents over 90% of
the biodiversity of the vegetation in this ecosystem.
A network of corridors is more effective than single links: it increases
opportunities for migrations; it reduces risk of links being broken
(e.g. fires, subdivision and subsequent clearing of some blocks).
Fencing to restrict grazing of corridor vegetation by domestic stock
very important, but be careful not to restrict movement of wildlife.
Consider habitat (e.g. rocks, hollow logs, leaf litter) for animals that
may be slow in migrating (e.g. small ground dwellers such as rodents,
lizards and snakes). Consider the provision of artificial nest boxes, or
placement of hollow logs within new plantings.
Co-operative action between local landowners may be necessary. Such
co-operative efforts can make the best use of available resources, and
allow for the most effective links between remnant patches.
Agro-forestry, using suitable local timbers, can be used to produce a
marketable crop, while temporarily (at least 30 years, and often much
more for most tree crops) linking remnant vegetation patches, and also
to act as a buffer around larger remnant vegetation patches.
Edge Effects
'Edge effect' is a term used to describe what occurs with regard to
vegetation and wildlife when one type of vegetation shares a border with
another. They may occur naturally (e.g. forest grading into woodland,
or stream side vegetation to drier nearby slopes, and burnt and un-burnt
areas); or they can be man-made, such as pasture abutting forest, or
roads through forest. Some edge effects can be positive in terms of
native flora and fauna, but most tend to have negative effects. Edge
effects are most likely to have an influence on narrow strips or small
remnant areas. In terms of corridor plantings the wider the corridor the
less impact of "edge effects".