BCB 341 Principles of Conservation Biology RESTORATION ECOLOGY

BCB 341: Principles of Conservation Biology RESTORATION ECOLOGY Lecturer: James Reeler

INTRODUCTION TO RESTORATION q q q q 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 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

TERMS q q q 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.

WHY RESTORE? q q q 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: q q q 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

INCENTIVES FOR RESTORATION q Material benefits: q q Existential reasons: q q q 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 Improves personal relationships with nature (especially when conducted at a community level) Empowers people and stimulates stewardship Heuristic reasons: q q Allows the study of ecosystem services through reassembly Trial & error through hypothesis construction & testing (restoration ecology)

APPROACHES TO RESTORATION 1 q No action q q Rehabilitation q q q 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 q q q Too expensive Previous attempts have failed System may be able to recover on its own (eg: agricultural fields returning to the wild) Restore some ecosystem functions & some original species Start with hardy local species, leaving rare species for later efforts Complete restoration q Restore complete original species composition, structure & function through a comprehensive reintroduction process

APPROACHES TO RESTORATION 2 Ecosystem function Replacement using a few species (rehabilitation) Replacement using many species (rehabilitation) ORIGINAL ECOSYSTEM Biomass, nutrient content, etc. Complete restoration to original Partial restoration No action; ecosystem recovers on its own via succession DEGRADED ECOSYSTEM No action; continued deterioration Number of species & ecosystem complexity Ecosystem structure

CASE STUDY: THE HEATH FRITILLARY 3 q q q q Mellicta athalia has declined rapidly in England since 1950. Relies on woodland habitats Larvae eat common cow wheat, Melanpyrum pratense, which is found in clearings 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 20 th century, coppicing was no longer economic, & was abandoned Identification of this process had dual impacts: q q q 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 1980 s was very successful

CASE STUDY: THE LARGE COPPER 4 q q q q Extinct in England due to removal of wetland habitats in 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 Eggs laid on water dock (Rumex hydrolapathum) 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

IMPLICATIONS OF THESE EXAMPLES q Autecolocial studies are necessary to reveal complex linkages between species & environment q q q Single species can act as the focus for restoration q q 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 q q q 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 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.

EASE OF RESTORATION: SOIL Top and sub soil removed

VEGETATION Obviously linked to the soil development q If soil is intact, then recovery should be relatively simple, through a successional process. q In extreme situations, recovery may be limited due to depleted seed bank or changed soil status q Most common method of accelerating restoration is bypassing immigration process (may be slow if isolated from colonisers q Immigration rates affected by dispersal method and propagule type q Slow migrating species (eg legumes) can be Beachfront revegetation in introduced manually, through collection of seed from a Australia donor site q Seeds: large numbers possible q Seedlings: higher survival rate, especially if viable sites identified 5 q Saplings: god survival rate, large time and effort involved in growing and transporting q Nutrient status may require fertilisation – too much may favour grasses q

POLLINATOR COMMUNITY q q q q 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 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

CASE STUDY: HWANGE COAL MINE q q q q q Mine tailings are carbonaceous shale (very high C content, smoulders on contact with air) Tailings covered with subsurface soil from new opencast areas Soil p. H ~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 3 t/ha required to increase p. H to ~5 Planting of low p. H 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

CASE STUDY: HWANGE COAL MINE q q q q q Natural succession process initiated. Nearest natural habitat 1. 2 km over burning mine dumps! Years 1 -3: limited growth, periodic burning. Grasses successful Year 4: shrubs increasing in coverage. Pitfall traps catch 15 spp 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

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

RESTORATION: CONS q q 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 q q 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

SUMMARY q q q 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.