BCB 341: Principles of Conservation Biology

1. BCB 341: Principles of Conservation Biology Restoration ecology Lecturer: James Reeler

2. Many areas are partly destroyed or degraded through human action. • This need not be a permanent state of affairs • Restoration is possible on a local basis provided materials (reservoir of local species) and expertise are present • Provides an opportunity to put research findings into practise Introduction to restoration • Great potential for enlarging and connecting conservation areas • May be a misuse of resources – pros and cons of restoration must be added carefully • The active corollary to conservation biology – rather than protecting areas that are under threat, it attempts to increase the extent of “natural” areas

3. Ecological restoration – the practice of restoration. • “The process of intentionally altering a site to establish a defined, indigenous, historic ecosystem. The goal of this process is to emulate the structure, function, diversity and dynamics of the specified ecosystem” (society of Ecological Restoration, 1991) • Restoration ecology – the science of restoration (refers to research and study of restored populations, communities & ecosystems. • Mitigation process(offsets) – where a new site (often incorporating wetland areas) is created or rehabilitated as a substitute for another area which is destroyed or undergoing development. • Reference sites - areas with a comparable species composition and ecosystem structure that are used to determine appropriate introductions and processes for a restoration site. Terms

4. Disturbance and damage to an ecosystem can be a natural process (eg: lightning-triggered fires) • In this case, recovery to a stable climax community raises the biological diversity briefly and undergoes a process of succession • Some systems may be so damaged that they are unable to recover by themselves: • Mine sites/dumps – high erosion rate, potential soil toxicity, low nutrient status • Areas where degrading agent is still present cannot undergo restoration (eg: overgrazed areas) • Where original species assemblage has been extensively eliminated with no source of colonists Why restore?

5. Material benefits: • Economy depends on balance between developed & natural areas (ecosystem service) • (eg) costs money to clean polluted water, but natural sources provide it free • If development impinges on ecosystem function too heavily, the economy & quality of human life deteriorates • Existential reasons: • Improves personal relationships with nature (especially when conducted at a community level) • Empowers people and stimulates stewardship • Heuristic reasons: • Allows the study of ecosystem services through reassembly • Trial & error through hypothesis construction & testing (restoration ecology) Incentives for Restoration

6. No action • Too expensive • Previous attempts have failed • System may be able to recover on its own (eg: agricultural fields returning to the wild) • Rehabilitation • Replace degraded ecosystem with another, using simple species assemblage (eg: turn degraded forest into productive pasture) • Establishes a functioning community on site & restores ecosystem services • Partial restoration • Restore some ecosystem functions & some original species • Start with hardy local species, leaving rare species for later efforts • Complete restoration • Restore complete original species composition, structure & function through a comprehensive reintroduction process Approaches to restoration1

7. Approaches to restoration2 Ecosystem function Replacement using many species (rehabilitation) Replacement using a few species (rehabilitation) ORIGINAL ECOSYSTEM Complete restoration to original Biomass, nutrient content, etc. Partial restoration No action; ecosystem recovers on its own via succession DEGRADED ECOSYSTEM No action; continued deterioration Ecosystem structure Number of species & ecosystem complexity

8. Mellictaathaliahas declined rapidly in England since 1950. • Relies on woodland habitats • Larvae eat common cow wheat, Melanpyrumpratense, which is found in clearings Case Study: The heath Fritillary3 • Adults require hot sunny clearings in woods for flight, mating & oviposition • Historically, these were provided by the practice of coppicing – different areas cut every year • By early 20th century, coppicing was no longer economic, & was abandoned • Identification of this process had dual impacts: • Showed a management practice that would correct the problem • Demonstrates a method of restoration for whole communities in the English countryside dependent on rotational coppicing • Restoration programme in the 1980s was very successful

9. Eggs laid on water dock (Rumexhydrolapathum) on habitat edges in sunny areas. Not found in open areas of male habitats • Dispersal pattern indicates a mosaic of landscape habitats is required for survival. • Currently sufficient foodplants, but insufficient male territory, & too many movement barriers • Fen restoration project advocates restoration of areas of open fen & reedland, which would also allow reintroduction of the species • Illustrates restoration must take into account landscape-level & microhabitat requirements Case study: The Large Copper4 • Extinct in England due to removal of wetland habitatsin East Anglia • Research undertaken in Netherlands to assess possibility of restoration in England • Males require open fen meadows with nectar plants as territory – network of sites is needed

10. Autecolocial studies are necessary to reveal complex linkages between species & environment • These species-environment linkages are essential & must be studied before carrying out restoration • Where habitats are already influenced by human activities, monitoring & study outcomes will affect long-term management processes • Single species can act as the focus for restoration • Often hard to carry out restoration due to lack of knowledge of the goal • Endangered species within the habitat can act as a focus and show the ecosystem function • Flagship species also provide a public focus for the project • Rare species challenge us to restore complex communities • Complex life cycles & specific habitat requirements in micro- & macro scales • By restoring habitat to near original status, other non-focus species will benefit • Single foci are often insufficient, but with several flagship indicators a functional system can be constructed. Implications of these examples

11. Ease of restoration: Soil Top and sub soil removed Top and sub soil removed

12. Obviously linked to the soil development • If soil is intact, then recovery should be relatively simple, through a successional process. • In extreme situations, recovery may be limited due to depleted seed bank or changed soil status • Most common method of accelerating restoration is bypassing immigration process (may be slow if isolated from colonisers • Immigration rates affected by dispersal method and propagule type • Slow migrating species (eg legumes) can be introduced manually, through collection of seed from a donor site Vegetation Beachfront revegetation in Australia • Seeds: large numbers possible • Seedlings: higher survival rate, especially if viable sites identified5 • Saplings: god survival rate, large time and effort involved in growing and transporting • Nutrient status may require fertilisation – too much may favour grasses

13. Spread and success of many species depends on pollinator presence (usually insects, sometimes birds/bats/rodents) • Bumblebees required for some spring flowers, but they have a limited foraging range • If no neighbouring vegetation of the appropriate type, then pollinators will be absent • Initial restoration may have to focus on species with generalist pollinators Pollinator community • Synchrony of flowering & pollinator activity is also a problem • Handel (1997) advocated introducing sequentially flowering species to ensure pollen presence for pollinators • May mean compromise between old & new communities

14. Mine tailings are carbonaceous shale (very high C content, smoulders on contact with air) • Tailings covered with subsurface soil from new opencast areas • Soil pH ~3 • Initial process – cover sides of dumps with extra soil to prevent erosion introducing air (subterranean burning); change slope angle • Seed soil with pit ash from coal burning (ph~8). Approximately 3t/ha required to increase pH to ~5 Case study: Hwange Coal Mine • Planting of low pH tolerant grasses from local area to fix soil for movement • Gathering of local tree/shrub seeds • Scarification, growth in nursery, planting • Watering • Introduction of artificial wetland for processing mine waste; clay-lined & seeded with wetland species

15. Natural succession process initiated. • Nearest natural habitat 1.2km over burning mine dumps! • Years 1-3: limited growth, periodic burning. Grasses successful • Year 4: shrubs increasing in coverage. Pitfall traps catch 15spp ants, 20 beetles. >20 spp butterflies present • Year 5: Numbers of insects present increases, birds arrive as trees grow. • Year 10: sample show >25 unseeded tree species, several grasses. Baobabs transplanted! • Overall, the process was very successful • Caveat: Erosion is a big problem. Eventually pit slope walls will be eroded, initiating large subterranean burns. • Solution: ensure slope vegetation is viable in the long term & make end walls very thick. Provides time for leaching? • Functional ecosystem sitting on a time bomb Case study: Hwange Coal Mine

16. Can be carried out at all scales • Large scale projects tend to be expensive • allow whole landscapes to become functional ecosystems • link conservation areas • Small scale projects more common • Opportunities for local involvement • Provides education & highlights importance of ecosystem services • Opportunities increasing in developed world: • De-intensification of agriculture • Abandonment of agricultural land • Availability of post-industrial sites (often near cities • Developing world: • Additional opportunities for cultural preservation of land-based cultures • Environmental knowledge: people are less likely to degrade land when they understand its worth Restoration: Pros

17. Generally very expensive, even in comparison to establishment of conservation areas • Limits to what it can do – restoration is not an exact science, and it is unlikely to provide a fully-functioning ecosystem in most cases Restoration: cons • Overly optimistic mitigation expectations allow development to progress in sensitive areas • Last is very important, as offsets are often provided for large developments • Environmental consultants who carry out EIAs are developing expertise in restoration, & may profit from mitigation measures • Claim that mitigation is viable without real evidence

18. Protecting habitat is more effective than restoring it • Offers positive action to repair some of the damage to biodiversity • Biggest challenge is understanding the complexity and interactions of biodiversity and how to make them function after disturbance • Can be very beneficial to local communities, but can be misused to argue for translocation schemes/ habitat creation schemes with little chance of success • Requires constant monitoring to assess success and long-term management to assist in succession processes • Should not be used as an excuse to allow development in sensitive areas. Summary