Habitat Management Flashcards
What is reference number 1
Sutherland, W. and Hill, D. (1995). Managing habitats for conservation. Cambridge: Cambridge university press
what are the differences in flowing and static waters
water movement - if waters are moving so are other things, oxygen movement, organism movement, one way movement in rivers whereas static waters are more surface movement and mixing but not directional, impact on sediment water movement,
open (in out) system vs closed system - if you get pollutents, nutrients and organisms they tend to build up in the system vs flowing water
differences in management - speeding up ecological succession static need a lot of management, flowing open systems arrive and leave again meaning little management as theres no build ups, ecological succession is taking place but its not speeding it up in the same way as static water
what are the origins of waters
flowing - tend to be natural but modified by man in some way elgl the thames river
static - tend to be un natural, few natural static waters e.g. lochs in scotland because theyre large and have gone through ecological succession very slowly and uplands but lowlands are man made. natural lowland static waters dried up and turned into woodlands (gone through ecological succession)
what are the differences in flowing and static waters
water movement - if waters are moving so are other things, oxygen movement, organism movement, one way movement in rivers whereas static waters are more surface movement and mixing but not directional, impact on sediment water movement,
open (in out) system vs closed system - if you get pollutents, nutrients and organisms they tend to build up in the system vs flowing water
differences in management - speeding up ecological succession static need a lot of management, flowing open systems arrive and leave again meaning little management as theres no build ups, ecological succession is taking place but its not speeding it up in the same way as static water, pollutants act as nutrients for algae resuting in eutrophicaion
think about water flow relative to its size - a small trickle wont move much compared to a river
what are the wildlife values/benefits/needs of water
habitat - wading birds, water voles, fish, inverts, plants
water source
what are the methods of control for waterbodies
cut, spray, dredge or rake
say which is best for each situation a thats where the marks are
in waterbodies what determines plant growth?
abundance of dissolved nitrogen and phosphorus levels , nitrogen is rarely inadequate for plant growth but phosphorus can be limiting
are eutrophic waterbodies natural?
most are man made and include reservoirs, lakes and ponds.
what type of management do lowland STANDING waterbodies benefit most from?
active recreation: there is often considerable potential to modify habitats to benefit scarcer species and minimise impact of human disturbance but integration of this with other uses needs careful planning.
advantages of phase 1 habitat survey over nvc
- quicker to do
- requires less specialist botanical knowledge
- NVC is much slower as its more indepth and requires multiple visits over the year as diff plants grow in diff seasons
- phase 1 is widely used by ecologists and clients as its quick and cheap
- useful for coded maps
disadvantages of phase 1
- not very advanced
- wont learn all there is to know about the flora of a site as you only make one visit in one season
what are the 8 factors for static water management
Six natural:
Geography (location, topography and geology) Quantity of water Quality of water Depth of water Waves Context
Two man-made:
Pollution
Disturbance
what is reference number 2?
Lake, S. (2014). Britain’s Habitats: A Guide to the Wildlife Habitats of Britain and Ireland. 1st ed. Princeton University Press.
what is dystrophic static water
Dystrophic: describes a pond or lake containing unusually acidic brown water, lacking in oxygen, and unable to support much plant or animal life because of an excessive humus content
define heathland
an area of open uncultivated land, typically on acid sandy soil, with characteristic vegetation of heather, gorse, and coarse grasses.
Dominated by under-shrubs (0.5m) On nutrient-poor soils On acidic soils Mostly heather - Calluna vulgaris Plus: Erica, Vaccinium and Ulex species
causes of heathland losses
Lowland heaths:
Abandoned
Succession to woodlands
Forestry
Upland heaths:
Overgrazing
Conversion to grassland
Forestry
what is the conservation value of lowland heaths
Lowland heaths:
Vegetation type
Plant species
Reptiles and amphibians - sand lizards
Birds
Insects
conservation value of upland heaths
Upland heaths:
Vegetation type
Birds - red and black grouse, hen harriers
describe 4 stages of heather life cycle
Heather - Major heathland structural plant
Each plant has four life phases:
Pioneer (3-10yrs); seedling
Building (7-13yrs); dense dome
Mature (12-30yrs); centre opens
Degenerate (>30yrs); collapse
significance on conservation of heather lifecycle in heath?
Significance:
Height and vigour influence other species
So phases important in management
main problems of heath management
Emphasis now mostly on heather
Four major problems:
- Natural succession:
Under grazing; woody plants and/or bracken invade
Mostly lowlands
- Nutrient build up:
Natural
Fertilizers
Acid rain
- Over grazing:
Grassland, mostly uplands
Magic number, 2 ewes/ha in winter
- Fragmentation:
Housing, roads etc.
Mostly lowlands & animals
Problems compounded by interactions:
Fragmentation by other problems
Nutrients cause succession
Over and under grazing
causes of heathland losses
Lowland heaths:
Abandoned
Succession to woodlands
Forestry
Upland heaths:
Overgrazing
Conversion to grassland
Forestry
Lowland heaths:
Problems: Under-grazing and fragmentation
Solution: Cutting and restoration
Upland heaths:
Problem: Over-grazing
Solution: Economic and political issues
describe 4 methods of enhancement techniques for heathland problems:
bracken, nutrient depletion, overgrazing,
Bracken control:
Deep rhizomes are a problem Mechanical or chemical control Mechanical: repeated cutting or rolling Chemical: Asulam Both, best in the early summer Both, expensive and temporary
Nutrient depletion:
Mow and remove (or burn) but this is slow
And fires cause enrichment
Better to remove top of soil
But there is a problem with disposal
Over-grazing:
Remove stock But economics Supplementary winter feed But adds nutrients Trampling and/or grazing hot spots
describe three maintenance methods for heathland
- Grazing:
Traditional Best, produces a mosaic But lowlands no stock And uplands too many Best 2 ewes/ha in winter N.B. Sheep eat heather in winter
- Muir burning:
Traditional to the uplands
Removes old wood and encourages new shoots
Mixed small patches suitable for grouse
Short for feeding and tall for hiding
Can replace grazing in lowlands but uniform
- Cutting:
Not traditional
Can replace grazing in lowlands
Safer, but produces cuttings
Need to remove cuttings
main problems of heath management
Emphasis now mostly on heather
Four major problems:
- Natural succession:
Under grazing; woody plants and/or bracken invade
Mostly lowlands
- Nutrient build up:
Natural
Fertilizers
Acid rain
- Over grazing:
Grassland, mostly uplands
Magic number, 2 ewes/ha in winter
- Fragmentation:
Housing, roads etc.
Mostly lowlands & animals
Problems compounded by interactions:
Fragmentation by other problems
Nutrients cause succession
Over and under grazing
define a mire
Mires (bogs and fens) are herbaceous, terrestrial ecosystems
The soils are organic and water-logged
The water level is at the soil surface
Reed beds (fens) – considered here too
what is the origin of the soil for mires
In a mire, the plant communities form the peat, the soil in which they grow.
Peat accumulates at a rate of about one millimetre a year.
Origin of the organic soil:
Peat substrate
Water-logged
Anaerobic environment
Litter does not decay
Litter accumulates
what are the two major types of mires?
- Bogs:
Ombrotrophic - ‘rain fed’
pH 4
Nutrient poor
Sphagnum mosses, sedges and heaths
- Fen:
Minerotrophic – ‘ground water fed’
pH 5 – pH7
Nutrient richer
Tall grasses, sedges and rushes
what are the two main types of bogs?
Two main types:
Raised bogs:
Shallow domes on flat land or basins
Blanket bogs:
Sheets on gentle slopes (10o) (and valley bogs)
what are the stages of succession in mires
Stages of succession:
Open water, to… Reed beds (swamp), to… Fen, to… \+/- Fen woodland (= Carr), to finally… Bog
Significance of succession:
Fens; short-lived so require much management
Bogs; long-lived so require little management
what is the wildlife importance of fens and bogs
General wildlife interest
Natural and semi-natural habitats
Fens and reed beds:
Rare birds and invertebrates
Bogs:
Area of habitat
Plus some species
name some animals that live in bogs
The Raft Spider is one of the largest, and scarcest spiders in Britain.
It inhabits pools on bogs and wet heaths, where it skates across the surface.
If disturbed it breaks the water surface and dives.
golden plover bird, bog bush cricket, common crane (fens)
name some animals that live in bogs
The Raft Spider is one of the largest, and scarcest spiders in Britain.
It inhabits pools on bogs and wet heaths, where it skates across the surface.
If disturbed it breaks the water surface and dives.
golden plover bird, bog bush cricket, common crane (fens), bitterns, marsh harrier (fens), marsh orchids
what are the general management techniques for bogs/mires
General:
General problems and solutions Modified by site and / or rare species Maintain / enhance mostly Little restoration Remember variety
what is the difference between bogs mires and fens?
reedbed, fen and acid bog habitats are generally part of the succession from open water to woodland
differences between them being due to water chemistry, hydrology, geology and climate
what is the method of management for conservation for mires and fens
focuses on the early successional stages with aims to halt or slow succession because lack of management of fens and reedbeds has led to succession and as a result lots of woodlands have sprung up with only small areas of open vegetative communities remaining.
what is the management method for bogs?
bogs are generally stable and only require low levels of management or even none at all but they are threatened by peat extraction, drainage and invasion or afforestation by exotic conifers.
define a bog
characterised by short vegetation particularly sphagna bt including mosses, sedges and dwarf shrubs. other vegetation inc trees is always due to disturbance e.g. from drainage.
give an example of how drainage can cause problems for raised bogs
drainage of the lagg will have an effect on the hydrology of the dome which leads to the sphagnam covered surface drying faster and the eventual colonisation by trees, pools and ridges
how are blanket bogs formed
they smother large areas of level or gently sloping ground under a ‘blanket’ of peat. Also known as ‘flow’ or ‘floe’, they are the most extensive type of mire fed entirely by rainfall and snowmelt rather than groundwater.
refers to ombrotrophic mires
true blanket mire peat can form directly on acid nutrient poor podsols and even over bare leeched rock.
the depths of the peat depends on waterlogging and stagnation reaching up to several metres deep.
are blanket bogs natural
yes but there are some evidence of man made ones as iron age agriculture may have contributed to the development of blanket peat
what are the problems with blanket bogs?
Peat is a precious resource that can take thousands of years to form and peat bogs are important habitats for a whole range of species from bog bush-crickets to hen harriers. However, our peat bogs have been overexploited by the commercial extraction of peat, particularly for horticulture, and have been irreparably damaged by drainage, afforestation and inappropriate management.
Peat is still growing on some active bogs, but the rate of formation is greatly exceeded by the rate of loss. Poorly managed grazing, intensive burning and acid rain all cause erosion, while peat-cutting exposes the underlying bedrock. The subsequent loss of sponge-like blanket bog causes flash flooding and erosion downstream.
how does drainage negatively affect mires and bogs
Drainage ditches, l lower the water table
may initiate erosion and oxidation of the peat.
Lowered water tables will alter the species composition of the surface vegetation and have a detrimental affect on specialist invertebrates.
Drainage at the margins of bogs will lower the water table and may modify the surface patterning, such as loss of Sphagnum hollows.
how will afforestation negatively affect mires and bogs
Coniferous trees have been planted on extensive areas of blanket bog in the past. The trees will continue to affect the hydrology and species composition of adjacent areas of blanket mire as they mature and require more water. Afforestation has generally been accompanied by furrowing of the ground, and these highly destructive drainage channels become a long-lasting scar.
give more specific details of management techniques for bogs/mires (hydrology)
As a peat bog consists of 95-98% water held by Sphagnum peat, the water level is the most crucial aspect to consider when managing this Priority habitat type. Operations some distance away from the ombrotrophic Sphagnum communities can have a devastating effect if they are on sites within the same hydrological unit.
Drainage ditches and forestry plantations will remove water from surface layers of the bog and ultimately lower the bog surface, favouring plants which grow in drier conditions, affecting any specialist invertebrate species.
Wet blanket bog is of great importance to many invertebrates such as spiders and leaf-hopper bugs. Drying peat will shrink and oxidise, creating erosion problems and increasing vulnerability to fire damage, so it is essential to maintain water levels. On sites that are drying, raising the water levels should be considered. -
why is the burning management technique bad for blanket bogs
Burning destroys large numbers of invertebrates, potentially entire populations of species living wholly in the above-ground parts of plants. In acid sites it can also encourage purple moor-grass at the expense of other vegetation. Too hot a burn can kill bog-moss and burn into the peat, altering plant communities and damaging invertebrate interest.
Heather management through burning appears to be especially damaging to plant-hopper bugs, sensitive species taking a long time to return. Burning should be therefore replaced with a more sympathetic form of management such as cutting or low-level grazing.
why is nutrient enrichment management bad for blanket bogs
Pollution incidents and nutrient enrichment lead to the loss of Sphagnum bog vegetation reducing its ability to support species such as the rare Wybunbury Moss carol-rita spider Carorita limnaea.
give another specific example of blanket bog management
prevent growth of scrub and trees
If water table levels are maintained then significant scrub invasion should not present a major problem as the very wet, infertile ground conditions, altitude and exposure of the blanket bogs often makes tree or shrub growth difficult. However, in areas of bog that have already begun to dry as a result of drainage or agricultural operations, scrub invasion can be prevented by cutting or light grazing, but it is important not to overgraze. Grazing can cause problems to blanket bog habitats, causing damage to the vegetation by trampling and affecting the species composition if nutrient enrichment occurs by the deposition of dung
what are the main problems of raised bogs
• Peat extraction
Removal of peat in existing and proposed new areas
• Landfill development
Use of cut-over bogs for landfill
• Afforestation
Trees (and associated furrows) dry out neighbouring areas and act as an invasive seed source.
• Drainage
Neighbouring agricultural areas require lowered water levels via marginal ring-ditches and other intrusive drainage measures. Drying out the raised bog through drainage allows invasion by scrub and trees which it turn speed up the drying out process and lead to the loss of special habitat and fauna.
• Water abstraction
Abstraction of water within the catchment area will have an adverse effect on the hydrology of a raised bog.
• Pollution
Run-off from agricultural land (fertilisers and pesticides) will damage the ecology of the bog.
• Livestock & game management
Drainage, trampling, burning, contamination with feed and droppings
• Built development (roads etc)
Apart from direct impact, the natural hydrology is disrupted
• Climate change
- See more at: https://www.buglife.org.uk/advice-and-publications/advice-on-managing-bap-habitats/lowland-raised-bogs#sthash.olkkqB3z.dpuf
what are the same management techniques for both types of bogs?
hydrology, prevent scrub encroachment, avoid burning and avoid grazing
name a specific management technique for raised bogs
Relatively undisturbed lowland raised bog surfaces are not uniform; they are made up of an almost continuous carpet of Sphagnum with a microtopography of hummocks and hollows providing a range of conditions that support invertebrates. It is important to minimise human activity on undisturbed raised bogs; wet Sphagnum communities are fragile and easily damaged by trampling.
Shallow bog pools should never be deepened or cleared, as their invertebrate interest is likely to be far greater than any larger pool that is created.
what are the main threats/problems for fen
Drainage for conversion to intensive agriculture
Past drainage of surrounding areas of land has lowered water tables and led to drying of remnant fen habitats
Water abstraction
Excessive water abstraction from aquifers dries up or reduces spring line flows, lowers water tables and affects water quality
Nutrient enrichment
Nutrients from agricultural run-off and other sources leads to eutrophication of fen waters and a change in plant communities
Afforestation
Afforestation within the catchment areas can lead to drying
Poor management
Lack of appropriate management to prevent drying, deterioration in herb richness, scrub encroachment and succession to woodland
what are the management techniques for fen
maintain structural diversity - all succession stages of fen provide important invertebrate habitats and should be retained where these occur naturally. Management should be carried out in rotation to ensure both longer and shorter vegetation is present at all times.
prevent scrub encroachment
what are the management techniques for fen
maintain structural diversity - all succession stages of fen provide important invertebrate habitats and should be retained where these occur naturally. Management should be carried out in rotation to ensure both longer and shorter vegetation is present at all times.
prevent scrub encroachment
retain areas of carr (wet woodland) which is important for wildlife and is species rich
maintain water levels to keep invertebrate habitats intact
what is the wildlife importance of reedbeds?
important for birds - 5 nationally scarce birds bittern, bearded tit, marsh harrier, cettis warbler and savis warbler breed in reedbeds.
reedbeds are also important pre migratory roost sites for hirundines and winter roosts for pied wagtails.
watervoles use them
management for reedbeds?
Scrub removal
Scrub encroachment should be discouraged over most of the area, but in some small areas scrub should be retained. The best method of removal is to pull out bushes, leaving small pools within the reed bed, which can support interesting invertebrates. Simply cutting scrub will have the effect of promoting thicker re-growth from stumps and may lead to an ever-increasing need for cutting.
hydrology: three diff techniques
- water maintained high all year
- water above ground level until after birding season, dropped to below ground level then raised again in autumn
- water held above ground in summer, dropped over autumn and raised in spring
depends on wildlife, 1 is good for animals that need wet conditions (bitterns), 2&3 allow scrub encroachment and drying of litter which is better for other birds
threats to reedbeds
• Loss of area
Large areas of reedbed can be lost by water abstraction, land drainage and conversion to intensive agriculture
• Lack of appropriate management
This can include too frequent harvesting/cutting cycle, of existing reedbeds leading to drying, scrub encroachment and succession to woodland
• Sea-level rise
Rising sea levels on the East coast of England are expected to lead to the loss of significant areas of habitat
• Pollution
Pollution of freshwater supplies to the reedbed
why is fen management different to reed management
same management can be used but fens have more complicated systems than reedbeds as they have a higher diversity of plant and animal species so messing with the hydrology will have more effect on the conditions plants and animals can survive in
what are the similarities and differences in management between fens reedbeds and bogs?
Fens and reed beds:
Constant management
Keep all stages of succession
Bogs:
Minimal management if undisturbed
If not, block drains and remove trees
