Habitat Restoration and Rewilding Flashcards
Why is habitat restoration and creation sometimes more important than conservation of a species?
supports a large number of species
increases biodiversity
creates food chains/webs
interspecies dependencies
Semi-natural habitats: hay meadows
grasslands - grow in spring/summer and are cut in autumn for hay
support soil microbes, insects, birds, fungi, small mammals
Semi-natural habitats: chalk (calcareous) grassland
originated from clearance of trees
maintained by grazing livestock
found over chalk and limestones (alkaline) - this leads to habitat specific plant species
Semi-natural habitats: upland moorland
maintained by human management (grazing + controlled burning)
popular for game shooting
supports mosses, lizards, adders, ground-nesting birds
Semi-natural habitats: lowland heathland
infertile, well-drained, sandy soils
managed by grazing and controlled burning
heathers, grasses
important for lizards and night jars
Semi-natural habitats: hedgerows
line of closely packed shrubs and trees
link together isolated habitats
important as nesting habitats
show boundary ownership
Semi-natural habitats: wetlands
land is covered by water seasonally/permanently
act as natural water filters - trap pollutants
rivers, marshes, bogs, mangroves
supports ducks, geese, kingfishers, otters, beavers
Semi-natural habitats: fen, marsh and swamp
3 main types of wetland
swamp = forested wetland
marsh = water logged to rain
fens = accumulate peat
supports dragonflies, beetles, spiders
Semi-natural habitats: saltmarsh
coastland wetland that is flooded by sea water
filters runoff and surface pollutants
salt tolerant plants
used for grazing and fishing
important for birds
Why do most semi-natural habitats in the UK require management?
the original reasons for these habitats no longer exist (e.g. winter food/seed can be sourced from anywhere)
Principles of Nature Reserve Design
Should cover a whole ecosystem/ecosystems
Highly biodiverse habitats are more important to protect
Wildlife corridors should be used to connect isolated reserves
Uniform shape to reduce edge effects
Smaller reserves may prove more effective if used as “stepping stones”
Abiotic features of a habitat
temperature
water availability
pH
mineral availability
salinity
wind velocity
light availability
soil type
Manipulation/Management: temperature
add a body of water = moderates temp
increase = remove vegetation/trees & decrease wind velocity
Manipulation/Management: water availability
increase = plant vegetation (transpiration), create ponds and dams/introduce beavers
decrease = remove dams, drain the area
Manipulation/Management: pH
increase = introduce rock salts
Manipulation/Management: wind velocity
increase = remove trees/ vegetation
decrease = plant thick vegetation in wind direction
Manipulation/Management: light availability
increase = clear trees/large shrubs
decrease = plant trees and shrubs
Manipulation/Management: soil type
sand = dry, clay = wet
introduce to balance the extreme
Manipulation/Management: salinity
plant adapted species
decrease = build dams to prevent water getting inland
Manipulation/Management: mineral availability
increase = use permeable rocks, slow down flow of water
Manipulation/Management: dissolved oxygen (aquatic ecosystems)
increase = introduce aquatic plants, increase water movement
decrease = fish
Biotic features of a habitat
type + number of predators
pollinators
seed dispersers
competitors
presences of pathogens/disease
plants + vegetation
food availability
Manipulation/Management: food availability
increase = plant vegetation (shrub=berries=birds), leave things to decay
Manipulation/Management: type + number of predators
biological controls
removal of invasive species = controlled cull
sometimes are keystone species (wolves at yellowstone)
Manipulation/Management: pollinators
increase = plant more wildflowers, reduce amount of pesticides (especially neonicotinoids)
Manipulation/Management: seed dispersers
increase = increase wind velocity, increase amount of birds
Manipulation/Management: competitors
reduce number of deer
remove invasive species (grey squirrels/rhododendrons)
Manipulation/Management: pathogens and disease
decrease = removal of disease vectors (e.g. grey squirrels) via controlled culls, administer vaccines and medicine
What is rewilding?
progressive approach to conservation
allows damaged ecosystems to repair themselves
Positives of rewilding
mass restoration of ecosystems
provides job opportunities
cost-effective
Example of rewilding causing a trophic cascade
reintroduction of wolves to yellowstone:
deers avoided valleys
trees grew faster
more migratory birds
increased beaver population
changed the meander of the river - banks were stabilised
Example of a trophic cascade caused by the removal of a keystone species
whales:
stimulate growth of phytoplankton
sequester millions of tonnes of carbon every year
when removed krill and crabs died
Rewilding examples UK: Wild Woodbury
170 ha community rewilding project in Dorset
red list bird populations increased
butterfly abundance rose 25% in 2022
Rewilding examples UK: Knepp Castle Estate
West Sussex
reintroduced old english longhorn cattle, exmoor ponies and tamworth pigs
