Restoring ecosystems can, however, provide a good return on investment (Figure 3.2.3).
The impacts of land conversion on biodiversity may be significant. The degree of impact relates to many factors, including where and how the bioenergy product is cultivated. The short-term impacts of land conversion are represented in Figure 3.2.5.
Gains and losses in forest area vary globally, and the impact differs greatly between the various crops used for biofuels (Figure 3.2.4). Forest-cover is enhanced through afforestation or by natural expansion, and reduced either by deforestation or natural disasters which may prevent forest from naturally regenerating itself.
Forest degeneration is often caused by overexploitation of forest areas by humans, pests, disease or recurrent forest fires. Generally, this implies a change in the health and vitality of a forest ecosystem. Reduced forest cover entails increased carbon emissions. Henceforth payment for ecosystem services, which contribute to conservation or increased forest cover, offer a promising way of countering climate change.
Converting land for biofuel production can cause biodiversity impacts in the short-term, but such conversion also affects the future resilience of natural ecosystems. In an extreme case, complete deforestation reduces the ability of forestland to regenerate and absorb carbon in the future (Figure 3.2.6).
Many plant species currently considered for advanced biofuels are potentially invasive. Materialisation of invasiveness depends on the landscape, climate and the way they are introduced. Thorough assessment is needed before such species are introduced, as well as appropriate management systems applied to protect native ecosystems and ecosystem services.
Figure 3.2.6 Forest carbon sequestration
The use of Genetically Engineered Crops (GECs) carries both potential benefits and risks. While it is recognised that they can help to introduce useful traits and increase productivity, there are also concerns about adverse ecological impacts.
balance between risks and benefits is likely to vary according to the different conditions of individual countries. It is advisable that comprehensive
biosafety risk assessments are conducted before governments make decisions on Genetically Engineered biofuel crops.
Beneficial effects for biodiversity are only expected when abandoned, formerly intensively used farmland or moderately degraded land is used and reconstituted; an agricultural-system approach must also be used.