Managing habitats
- Created by: maya
- Created on: 21-05-17 12:15
Measuring species diversity
key references are in moodle and available in all slides
Criteria based on biodiversity - these criterias are very important for the outcome of biodiversity
• Richness
• Rarity / endemism
• Similarity
Introduction
• In order to use species diversity in scientific studies it must be quantified
- most straightforward way to count species
• Most simply we can use Species Richness, which is defined as the number of species
• But the relative abundance of different species is also important
– It affects our measurement of species richness
– It affects the ‘perceived’ number of species by individuals within the community.
* relative abundance is key need to know this.
Introduction
• But the relative abundance of different species is also important
Which is the most diverse community A, B or C?
The shape of the abundance distribution is encapsulated in the concept of EVENNESS
More even, more diverse!
nature is pretty much like A, fewer species with more individuals <- hyperdominant species less rare.. at the end of the graph rarer species - few number
Collector’s curves (species accumulation curves)
• These show how the recorded number of species increases with sample size towards the real total species richness of the community.
• They also allow us to assess whether the amount of sampling is adequate to characterise the community.
The number of species increases when you collect more individuals- related with number of samples. then youre going to reach the limiting factor- cant collect any more species - stop sampling expensive
The more even the community, the steeper the accumulation curve
Diversity indices
Are range of indices that have been developed to simultaneously measure species richness and abundance distribution (evenness)
• Simpson’s index:
• Shannon-Wiener
Similarity of communities
• Often it is useful to give an index which tells us how similar two communities are
• Two common similarity indices are:
- Jaccard Index (shared individuals between two sites)
a score of 0.3 means the sites share 30% of species
– Sørensen Index
Similarity indices (Jaccard) are important to define complementarity areas
Representing as much biodiversity as possible in a limited area of land available for conservation
Hotspots for African mammals based on species richness, endemicity & complementarity
Endemism
How many shared tree species? Jaccard…
Cerrados shared a much larger proportion (55%) of their flora with Atlantic forests than did Amazonian forests.
A global assessment of endemism and species richness across island and mainland regions (Kier in PNAS)
Endemism and species richness are highly relevant to the global prioritization of conservation efforts in which oceanic islands have remained relatively neglected. When compared to mainland areas, oceanic islands in general are known for their high percentage of endemic species but only moderate levels of species richness, prompting the question of their relative conservation value.
areas which you should conserve should be islands of the pacific- huge more endemic than any other type of forest in the world- full of species?
Bioquality Hotspots in the Tropical African Flora
The study used these Star ratings in combination with species distribution data to measure bioquality concept;;
1)High bioquality implies a high proportion of globally rare plants in an area – species that stand to be lost from the global pool.
The bioquality map reveals the most significant areas for global plant biodiversitycontinentally, but also reveals considerable variation within these areas at a more local scale.
Where, precisely, to position a new protected area? Where to develop infrastructure? How to measure the impact of a new development on biodiversity?
Managing habitats
Managing habitats is complex
What is the best criteria for selecting habitats for conservation?
What is the best ecological criteria for selecting habitats for conservation?
We need to consider complex landscapes and species…
Criteria for selecting habitats for conservation
Degree of representativeness (try to conserve maximum area possible- but wont happen in real world people not happy if you conserve everything)
Area
Degree of conservation of the habitat structure and function and restoration possibility (if forest can be conserved itself)
BAP habitats in UK
BAP = Biodiversity Action Plan
Classifcation by Natural England
Start to define which areas to onserve-both criteria work together-use biophysical information plus biodiversity to conserve area
Naturalness
Area
Fragmentation
Some examples
Limestone pavements
Lowland heaths
Upland oakwoods
Coastal sand dunes
NAF LLUC
Upland mixed ashwoods
• Total area in the UK ~ 67,500 ha
• Ash is the dominant species, also abundant oak, birch, elm, lime and hazel
• Biological important (richest habitats for wildlife in the uplands)
• Nature reserves in the Arnside & Silverdale AONB, Yorkshire Dales NP
Plant community associated with mixed Ashwoods
Lime, Primrose, Common Ash, Wood cranesbill, Hazel
Rare species
Lancaster whitebeam
Dormouse (Use this as a flag species, have to protect it. A flagship species is a species selected to act as an ambassador, icon or symbol for a defined habitat)
Threats to upland mixed Ashwoods
• Overgrazing by sheep, deer and rabbits
• Ash dieback disease
• Replacement of native trees with planted conifers and other non- native broadleved species (sycamore & beech)
• Cessation of traditional management practices such as coppicing
coppicing is regularly cutting trees down to a stump called a stool - the tree grows back quickly in most cases
Threats to Upland Mixed Ashwood - OARC
- Coppicing helps trees to increase their lifespan
- coppicing is good for wildlife and biodiversity because it creates a patchwork of conditions in the woodland each suitable for different sets of flora and fauna.
Ash dieback disease
Is a disease of Ash trees caused by a fungus called Chalara
Chalara causes leaf loss and crown dieback
Once a tree is infected the disease is usally fatal directly or indirectly by weakening the tree so it succumbs to attacks by other pests of pathogens e.g. honey funghus
First case discovered in 2012 expect to find new cases
not all trees die of the infection - some are likely to have genetic factors which give them tolerance of, or resistance to, the disease. Want to use recurrent selection to breed ash dieback disease tolerant trees.
Forest Rsearch industry given £2.4million research funding to help fight it
Forestry comission - source
Conservation Management of upland mixed ashwoods
• Grazing with appropriate animals and at suitable stocking level
• Traditional coppicing
• Remove no-native species if become dominant (Sycamore)
• Restore areas of plantation woodland to native woodland
Limestone pavements
• Total area in the UK <3000ha
• Geological and biological important
• Non-renewable resource
Common species associated with limestone pavements
• Herb Robert • Common Ash
Rare plants
Rigid buckler fern - narrow dispersal range endemic
Threats to limestone pavements - OIL
• Overgrazing of some upland pavements and abandonment of lowland pavements
• Illegal or incidental removal of pavements
• Legal removal of pavements by planning permissions
look like rocks no life there- not true
Conservation Management of limestone pavement - RA
• Remove no-native conifers and retain Juniper and Yew
• Appropriate animals used when grazing and at suitable stocking level
• Control of rabbit populations
• Coppicing
• Ensure pavement is not removed or damage
• Deer control and fencing of coppice regrowth
Sand dunes
• Cover c. 56,000 ha
• Examples from northwest England:
– Sefton Coast
– N. Walney
– Sandscale
• Important ecosystems and habitat for rare species: natterjack toad, sand lizard & fen orchid - threatened by tourism- tourist movement
Vegetation zones in the dunes
Foredune
• Lack of water • High salinity • Windy • Accretion of sand • Calcium rich • Low nutrient levels
diversity lowwwwww
Dune Slack
• High water table • Relative low salinity • High nutrients • Stable sand • Low pH
The dune slack is located down below with sheltered conditions for the creeping willow.
Diversity increases - cut me some slack I'm overworked fam
Vegetation zones in the dunes
Because there are better physical conditions for land restoration (plat restauration)
Diversity increases from foredune to dune slack
Plants
Plants in the foredune
Marram grass (Pioneer species binds sand and assists accretion) , sea holly and sea spurge
Plants in the dune slack
Bee Orchid
Rare species associated with dunes (flag species!)
Natterjack toad needs water
Fern orchid
Sand lizard
Conservation management of dunes
Aims to maintain the different communities found in the various stages of the duneland succession
Main threats:
• Destruction by housing development
• Over-stabilisation (increasing vegetation cover)
• Erosion due to trampling
related to beaches-dunes move around a lot - unstable environment 5km-. If we over-stablise it won't let environment work aroud this dynamic proceess.
Authorities eager to protect the dunes by planting marram grass - stablisation trap sand.
in some cases resulted in a fixed dune position. the flexibility of the natural dune is lost resulting gradual disappearance of the dune because of erosion, the natural protection is lost.
Conservation management of dunes CREEPPS
• Controlled grazing
• Reducing scrub & wood
• Educating people
• Encouraging development of young dunes
• Protecting paths with boardwalks
• Planting marram grass
• Sensitive areas access limited.
Take home message
• UKBAP habitats are selected based on rarity, area and naturalness.
• Different management actions are required to conserve different types of habitats.
• Upland mixed ashwoods are important reservoirs of wildlife diversity in northern Britain. Prevent new threats.
• Limestone pavements are physically resistant but one destroyed is effectively lost forever.
• Sand dune communities are easily damaged but if protected rapidly recover.
Take home message explained
• UKBAP habitats are selected based on rarity, area and naturalness.
- jaccards will be more critical like this- have a table (30) score areas- provide info- conservation
• Limestone pavements are physically resistant but one destroyed is effectively lost forever.
- move the rocks destroyed forever
• Sand dune communities are easily damaged but if protected rapidly recover.
Different ways to conserve these environments- think about how you're going to conserve that area, species diversity, how that area is connected= going to learn how to do biodiversity in the best way.
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