6-6-4-managing-ecosystems-sustainably

Managing Ecosystems Sustainably

• Sustainability is the ability of an ecosystem to maintain (or ideally increase) its biodiversity whilst simultaneously providing humans with the resources they need over a long period of time

• Humans, in the way that they set up and manage an ecosystem, are in control of whether that ecosystem is sustainable or not

  • The resource must be allowed sufficient time to replenish before being harvested so that it does not run out

  • No harm should be done to the ecosystem, its surrounding areas, or to species living within it

  • Practices that boost biodiversity are promoted

  • The long-term future of the ecosystem must be guaranteed

• Two examples of managed ecosystems for sustainability are commercial fishing and timber production

Commercial fishing

• The human appetite for fish and seafood is very high, and growing fast as the human population rises

• Fish is a lean and healthy meat source with good protein levels for growth

• Modern fishing fleets have technologically advanced systems that could if used irresponsibly, strip the oceans bare of the most desirable fish species in a matter of months

• Sustainable fishing means:

  • Leaving enough fish in the ocean

  • Protecting habitats and marine food webs that fish rely on

  • Human communities that catch and process fish can maintain their livelihoods

• Governmental regulation can be enforced by:

  • Establishing fishing quotas

  • Agreeing areas of the ocean where fishing is banned (eg. spawning grounds) and permitted (eg. within a country’s territorial waters)

  • Regulating mesh size of nets (to allow undersized/juvenile fish to escape)

  • Limiting the size of the fishing fleet by issuing licenses

  • Inspecting the catch as a fishing boat returns to port

  • Banning certain practices eg. gillnets (static nets that catch anything that swims by, and the fish struggle and die in distress)

  • Promoting sustainable practices such as trolling (different to trawling) that reduces bycatch

• Nevertheless, a lot of commercial fishing is carried out illegally

  • There is a very wide area of ocean for the authorities to patrol

  • High demand and profit potential has made poachers more daring and willing to break the law

Measures to make commercial fishing more sustainable

Trolling uses hook-and-line and reduces bycatch and damage to the seabed

Timber Production

• Human demand for wood and timber products fluctuates

  • In the mid-20th century UK forests were reduced to 5 % of the land area; today it’s back up to around 12 % through afforestation efforts

• Timber remains an important resource in today’s society, with many uses

• There is pressure on natural woodland to be felled and used as grazing land or for crop production, particularly in developing countries

• There are 2 main groups of tree crops used in commercial logging

  • Fast-growing conifers, e.g. spruce, pine, fir, larch

  • Slower-growing broad leaf trees, e.g. oak, beech, hazel

Fast-growing coniferous plantations

• Conifers are the fastest-growing trees in the northern hemisphere used as a strategic reserve of timber

• Low-grade agricultural land is used to grow these trees, creating an effective monoculture

  • Densely planted forests, deep shade, and needle litter at floor level all contribute to low biodiversity

• Work has been done to try and increase biodiversity in these areas

  • The use of felling methods other than clear-felling introduces pockets of variety into a plantation

  • Creation of clearings, firebreaks, selective felling, strip felling, edge habitat creation and in-situ leaving of naturally dead trees all attract other species and boost biodiversity

  • Genomic research has identified suitable sub-species, e.g. of Sitka spruce that can grow faster and shorten the tree breeding process

  • Recreation and public education projects now form part of the remit of forestry authorities

Coppicing and pollarding

• Coppicing and pollarding are felling techniques that can be used to sustainably manage slower growing broadleaf trees

• Coppicing involves felling trees close to the ground and leaving the stump of the tree in the ground; new shoots can grow from the stump and can be harvested again after around 7 years

  • Woodlands can be divided into regions and coppiced on rotation so that only small areas of the woodland will be lacking in mature growth at any one time

  • Coppicing means that trees remain relatively small and light can always reach the ground; this leads to more diverse woodland

• Pollarding is similar to coppicing but the trees are cut 2-3 metres above the ground, leaving the mature tree trunk in place

  • This brings many of the same benefits of coppicing but means that herbivores are less likely to be able to reach and consume the new shoots as they grow

• The timber produced by coppicing and pollarding is limited to use in smaller projects, e.g. fencing

  • The shoots that grow back after trees are cut in this way are long, thin branches; not one single stem

• Not all tree species are suitable for this type of management, e.g. very few conifers will grow back in this way after being coppiced or pollarded

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