4. Preserving the resilience of terrestrial ecosystems Flashcards
Structure of the lecture
- The current status of forest restoration
- The restoration of forests is immensely important across wider political, economic and social landscapes
- Current objectives for forest restoration
Resilience against pests - Continuous cover foresty can help us restore standing genetic diversity
- A range of different policies prioritise maintaining genetic diversity
Define resilience
1.1
Resilience is the capacity of an ecosystem to respond to perturbation or disturbance by resisting damage and subsequently recovering.
Resilience is seen at the landscape, ecosystem and species level, and is a long-term response
What is the current status of global forests?
1.2
Forests cover 30% of the land area of Earth, and contain 66% of terrestrial biomass. They are very diverse, and can be tropical (45%), Boreal (27%), Temperature (16%) or Sub-tropical (11%)
They are tightly linked with atmospheric carbon budgets
However, only 18% of forests are protected, despite immense global deforestation. However, changes in forest cover differ continuously by continent, and LICs will often have higher levels of protected forests. This is highly controversial in the face of economic development
What are the main threats facing global forests?
1.3
The main threat is deforestation in the face of material goods, such as timber and paper, for agricultural land, such as to farm cattle and sheep, and for urban expansion.
Other threats to forests include drought, pests, fires etc., and other natural disasters
Why is tree restoration important across the wider social-political landscape?
2.1
- Politics: Tree restoration supports BNGs, NDCs (Nationally Determined Contributions to policies like the Paris Agreement), and SDGs
- Social: Tree restoriation is an important step for ending hunger, inciting climate action, and improving life on land
- Agriculture: Ensuring that production of food can still occur, despite the need to maintain biodiversity of forests. How can we do this using mosaics, or integrated practices, or continuous cover forestry?
- Protection against natural disasters: Suitable for mangrove forests, watershed protection, and erosion control. Helps to mitigate against the increased frequency of natural disasters that will only accelerate with global climate change
- Allowing for recreation: Balancing land-sharing and land-sparing will promote forest landscape restoration, and allow for necessary agriculture and timber protection. With hard work, we can maintain the spritual, cultural and recreational meaning of a forest, whilst allowing for the economic impacts to be maintained/
Why is it important to maintain clear conservation goals when protecting global forests?
3.1
Maintaining the three pillars of nature: Ecological, Economical and Socio-Cultural needs
Our goals need to focus around sustaining more diverse ecosystem seervices, increasing species diversity, conservation and restoring natural ecosystems, improving practises, governance and policies.
What are the 6 UN Forest Goals 2021?
3.2
- Forest management, and reversing the loss of tree cover
- Promoting economic, social and environmental benefits by improving the livelihoods of forest-dependent peoples
- Increasing protected areas of sustainably managed forests across the world
- Financial resources to strengthend political, scientific and technical cooperation
- Governance frameworks to meet the 2030 Agenda for Sustainable Development
- Cooperation between governments, academics, cooperations and local people
What are sector-based objectives?
3.3
Providing different goals for different stakeholders, corporations, individuals etc,
What is a forest-type objective?
3.4
The nuance of setting goals, depending on the different types of forests that we are aiming for conserve.
For example, natural and semi-natural woodland is very biodiverse, and focus should remain on restoring ecosystem services via natural regeneration to improve resilience
Planted forests will have low species diversity, and focus should remain on timber production, meaning that artifical regeneration is required to maintain resilience
Degraded forests have very limited biodiversity, and focus should remain on re-establishment, using artifical regeneration and protection to restore and stabilise the forest
What are production-type objectives?
3.5
Production-type objectives aim to focus on different solutions for different damages.
For example, the Loblolly pine produces 19% of the world’s industrial rounded wood. If we switched to systems that allowed for establishment without clear felling, then this may allow for trees to continue to age, and simple ecosystems to emerge with some degree of diversification
What is the importance of maintaining lots of different types of goals within conservation?
3.6
Allows for nuance, and protection based on the individual needs of the forest, stakeholders, type of degradation, economic needs etc.,
Not having ‘blanket’ goals, means that it is easier to maintain the socio-cultural, ecological and economical needs of the forest
How are pests threatening the resilience of landscapes?
4.1
Increasing environmental change increases the pressure from pests, like insects and diseases. The impact of these outbreaks is similarly accelerating
What is a one good solution for improving resilience against pests?
4.2
Messier et al., 2021
Planting different mixes
More diverse species are less susceptible to disturbance, and thus will be able to continue to provide the necessary ecosystem serivces
Examples include the IDENT experiment, and the Sabah experiment in Borneo
However, it is important to understand the nuance that is involved here between different species of pests. Planting different mixes will only prove successful against specialist pests, and not against generalist pathogens.
How bad is the issue of generalism and specialism when considering planting different mixes to overcome pests?
4.3
A meta-analysis from Jacet et al., 2020 provided evidence for associative resistance and susceptibility. This paper analysed 624 study cases, across 69 papers between 1966 and 2019. The case studies were across 243 boreal forests, 312 temperate forests, and 71 tropical forests
They found evidence that there is a difference betweeen generalist and specialist insects, and the success of different planting mixes. Planting divers mixes may provide some resilience, but cannot be entirely successful
What other forest management practices can we use to provide resilience to pests?
4.5
- Favouring contrasing functional characteristics when planting
- Mixing plantations with natural regeneration (i.e., Continuous Cover Forests)
- Looking at potential trade-offs between timber yield and resilience in these areas
Define Continuous Cover Forestry? (CCF)
5.1
Mason et al., 1999
CCF aims to achieve high standing diversity at the landscape scale, as an adaptation to climate change and biotic risks
What are the 4 main, guiding principles for CCF?
5.2
- Managing the forest ecosystem
- Using natural processes to our advantage to minimise disturbance
- Working within the limitations of the ite
- Diversifying the standing structure of the forest
What are some of the challenges for CCF?
5.3
According to the forestry commission
Implementation of CCF is currently limited, and may be slow to increase
- Costs of management, and difficulties involving the acquisition of funding
- Knowledge and experience of CCF, which may be lacking even within a skilled workforce
- Machinery and equipment, which is available, yet costly
- There is not a great diversity of trees making up the forests within Britain, with 10 species accounting for 80% of all woodland
- The conversion of planted woodlands is difficult, especially when there are economic goals to be met. This continues to limit genetic diversity
What is an example of CCF?
5.3
Hemlock regeneration in Stourhead Western Estate in Wiltshire
Mixed woodland under CCF, with severa non-native conifer species planted
Natural regeneration can be variable and there is a gradual removal of trees needed to open up the canopy and overcome the shade tolerance. Genetic diversity is not the only limiting factor in a forest.
What is the Bonn Challenge?
6.1
A global effort for forest restoration that aims to bring 150 million hectares of deforested and degraded land into restoration by 2020, and 350 million hectares by 2030
Aims to restore ecological integrity, and improve human wellbeing through the provision of multi-functional landscapes
What is the Forest Landscape Restoration programme?
5.2
A practical means of realising the UNSDG. It aims to combine Aichi Target 15 with the UNFCCC REDD+ goals and the UN SDG by improving global forest cover from 10 to 13%
Tree planting is not the same thing as landscape restoration
What are the goals of the FLR programme?
6.3
- Focusing on landscape level restoration to balance ecological, social and economic priorities
- Maintaining and enhancing natural ecosystems within landscapes to avoid the conservation/destruction of natural ecosystems
- Engaging stakeholders and supporting participatory governance, particularly within vulnerable groups
- Tailoring to local context, in line with the values, benefits and history of the environment
- Restoring multiple functions for multiple benefits to resotre the social, economic and ecological benefits
- Maintaining long-term resilience of species and genetic diversity
Give an example of Landscape Restoration
6.4
Hector et al., 2023
Vervard et al., 2023
The Sabah Biodiversity Experiment in Borneo
Selecctive logging of an area in Borneo, and replanting with 1, 4 or 16 species.
They found that as the number species increased, the biomass increased, and vegetation cover increased
The number of species has a strong effect on biomass and canopy cover
They found that mixing multiple species produced the greatest biomass increase
