Forest Monitoring Flashcards
Which natural factors have affected the biodiversity in northern European forests?
Immigration patterns
Climatic fluctuations
Refuge populations
Disturbances such as: Wind, fire + fire refuge, insect attacts, humans
Which factors affect the biodiversity in forests?
Forest fire
– occurrence, interval and intensity
– tree species succession after fire
Occurrence and dynamics of gaps in the canopy
– mosaic of successional stages
– light gaps
– nutrient additions
• Continuity
– time to reach reproductive age
– dependency of structures that are developed after long time
– dependency of the microclimate in old growth forests
• Dead wood
– succession of necro fauna and flora on logs
– establishment of new trees
How does the forestry affect the bio diversity?
Clear-cuts, short rotation times, even-aged stands - Very little old forest, lack of stand continouty, changed stand climate
Ditching - Degrade wetlands, and forests on wet ground
Suppressed fires - Lack of fire-induced early succession and
burnt dead wood
Renewal by foreign tree species, provenances - Altered tree species composition, non-native species, non-site provenances
Reduction in amount and quality of dead wood - The largest single factor for decreased number of species (90% during 100 yr)
Decribe the factors that affect landscape fragmentation?
Altered landscape mosaic - Gives remeant biotopes and habitat fragmentation
Size of fragments - Larger are better, both directly and indirectly.
Fragment isolation - Can lead to inbreeding
Possibility to dispersal between fragments - Often ignored but very important. Part of the natura 2000 project but we generally know to little.
Genetic effects - Random demographic and enviromental factors may harm small populations.
Corridors - The form varies between species. The effect increases with width and quality.
Edge zones - Increased edge leads to higher predation, specialists from, different habitats co-occur.
Species with high risk for extinction
- Species at the top of the food web
- Species with local distribution
- Species with limited ability of dispersal
- Specialists
- Parasitic/symbiontic species
Describe DPSIR
A frame work by which policies are made:
Driving force - energy demand, life style, timber haverst, hunting license etc.
Pressure - Harvested area, ditches, alien tree species, S and N deposition.
State - Area of old forest, amount of decidiuos trees, dead wood, pH, nutrient balance, shot wild animals
Impact - Decrased bio div, uptake/relase of CO2, eutropfication, traffic accidents with wild animals.
Response - Forestry legislation, natyre conversation, refunds for attacts by large predators, fences along roads.
Environmental Quality Objective:
Sustainable Forests – Levande skogar
- The natural production capacity of forestland is preserved.
- The natural functions and processes of forest ecosystems are maintained.
- Natural regeneration is practiced wherever the land is suitablefor this method.
- The forests’ natural hydrology is protected.
- No remedial measures are taken against the effects of forest fires.
- Care-demanding forests with valuable natural and cultural assets are managed in such a way as to preserve and enhance these assets.
- Forests where there is great variation in the age of the trees and the composition of tree species are protected.
- Cultural monuments and environments are protected.
• Importance is attached to forests as sources of nature
experiences and recreation are taken into account.
- Endangered species and natural ecosystems are protected.
- There are viable populations of domestic plant and animal species living in natural conditions.
- Endangered species can spread to new habitats in their natural areas of distribution, thus ensuring viable populations.
- Alien species and genetically modified organisms that may be a threat to biological diversity are not introduced
Indicators of successs for sustainable forests
- Fraction damaged cultural remnants
- Amount of old growth forest
- Amount of hard dead wood
- Amount of hatching forest birds
- Amount of protected forest area – nature reserves
- Amount of protected forest area – biotope protection
- Amount of protected forest area – conservation agreements
- Area of old forests with a high fraction of deciduous trees.
What is the purpose enviromental quality criteria for the forest?
If possible they should tell if the measured state may cause effects on human health and/or human helath.
Or
Tell if measured value is high/low compared to the mean in Sweden
How is the deviation of the measured value assessed?
It is done by measuring it relative to dedcided reference value (an estimate of the pre-human conditions). This value is then given a value between 1-5 where 5 is the largest deviation from pre-human conditions.
Describe the levels, methods and important parameters that are used to qunatify biodiversity in forests?
In the landscape saterlite pictures, field work and GIS is ised to assess parameters like habitate distrubution, corridors, edge zones and fire zones.
In the habitate field work and saterlite are used to assess parameters like number of species, density relationships, indicators and key species.
On the species level population estimates/modelling and viability analyses are used. Factors that are assessed are frequency, distrubution, biomass, sex and age structure and fecundity.
On the genetic level morpholog varitaion, protein and DNA variation are studied to assess effective pop size, gene flow and heterozygocity.
Which factors does the Shannon diversity take into account when estimating diversity?
Number of species and the abundance of each specie.
What to alpha, beta and gamma say regarding biodiversity?
alpha - number of species in each sampling plot/unit
beta - Change in species composition between plots
gamma - Dibersity of the whole extent/forest/landscape
What are factors that can help in identifying a rare species?
What is the temporal trend? Any know threats? Is the species on national “Red lists”? What is the risk of extinction? Does the species provide an ecological function?
In what ways can diversity be measured?
Numerals: Spieces, genera families
Shannon diversity - Combination of quality and quantity
Genetic diversity - Is the diversity distrubed among or whitin the population?
Endemic - Rare in Sweden or everywhere?
Explain the different hypotheses about the need for biodiversity?
Rivet popper hypothesis - Spieces are like rivers in an airplane. When one disappear nothing major will happen, but if more disapperas it will at some point will decrease.
Redundancy theory - The ecological function in a system is persved as long as one species is there which fulfills each function.
Null hypothesis - The amount of species has no connection with the function in the ecosystem. Try to prove against.
Mutual losses - Loss of species leads to lower function in the ecosystem
Name structural key factors and which level they are on
National and regional level: • Potential and actual forest area • Site productivity • Tree species composition • Age structure • Afforestation, deforestation • Natural old growth forests • Legal status, protection
Landscape level • Forest cover continuity • Fragmentation of forest habitats • Forest habitat connectivity • Ecosystem diversity (incl. water bodies) • Land use history
Stand level • Stand size and shape • Tree species and structural complexity • Forest history • Successional stage, gap distribution • Dead wood (quality and amount) • Litter (quality and amount) • Variety of habitats within a stand
Name compositional key factors regarding biodiv in the forest:
National/Regional level
Native spieces
Alien spieces
Landscape
Species with large area requirments
Similiarity to potential natural vegetation
Stand
Species with specific requirments on stand type
Biological soil conditions
Non-site specific species
Name functional key factors in the forest regarding biodiversity
Natural distrubance:
Fire
Wind and snow
Biological disturbance
Human influence Silviculture Agriculture and grazing Other land use Pollution, erosion Climate change Introduced species Extinction of species
Descibe an indicator
A simple measure realted to something more complex of interest. Biodiversity is to complex to measure directly and we therefore need tools such as indicators to assess it.
Describe a flagship indicator
A flagship is a large charismatic vertebrate like the panda.
+ Good symbol
- Little use as inidcator of diversity
- Expensive to perserv
Describe an umbrella indicator
Is a species that needs a large and varied habitate, by protecting that one other also get protected -> under the umbrella.
+ Focuses on one species only, relatively simple
+ Many species get indirect protection
- Based on probability calculations
- Efforts that benefit the umbrella species may be disadventgous for other species
Decribe a keystone species
A species that secures the survival of many other species.
+ Focus on one species
+ Gurantees the protection of other species
+ Based on knowledge about ecosystems
- Hard to identify
- Unclear if they exist for all ecosystems
Describe an ecological engineer
A species that alters the habitate and thereby creates habitats for other species as well. Relatively similiar to keystone species
+ Focuses on one species
+ Gurantee for the survival of other species
+ Based on knowledge about ecosystems
- Few good examples
- Habitate alternation can create conservation conflicts
Describe a link specie
A specie that is important for the transport of matter and energy across trophic levels
+ Focuses on one specie
+ Gurantees ecosystem functions
+ Based on knowledge about ecosystems
- Based on probabilities
- Ecosystems indirectly monitored
Describe sensitive species
Is a specie with a narrow niche that reacts quickly to enviromental changes
+ Quick response
+ Directly related to biodiversity
- Need for taxionomic experts
- May not be good for detecting recovery
Describe insensitive species
Species that indicate degraded ecological status, reacts positive to high nutrion levels and often highly competive
+ Fairly quick response
+ Easy to detetct
+ Closely related to biodiversity
- Only indicate
- Only give ecological status
- No actual measure of diversity
Desribe an ailen/invasive specie
Species that evolved in a different ecosystem with different condtions that may outcompete native species. Can cause severe ecological and economical losses.
+ Easy to detect
+ Closely related to biologic diversity
- Only indicative
- Only gives ecological status
- No actual measure of diversity
What are desirable properties of an indicator?
• well-known and stable taxonomy
• have rapid responses to disturbances or habitat changes
• specialised on the ecosystem
• fairly common
• cheaply identified and sampled
• not be governed by demographic stochasticity
Trade off between
• Variability – not too much natural variation
• Sensitivity – environmental impacts must cause variation
that is possible to differentiate from natural variation
What are the pros and cons of chemical and physical indicators instead?
+ Simplier to measure
+ Well defined properties
+ No need for taxiomic experts
- Indirect measure of biological intregrity
- No direct correlation with bio diversity.
What are structural indicators?
Presence/frequency of certain physical structures indicates
occurrence of biodiversity properties of interest
Pros:
• simple
• cheap
• require little field expertise
Cons:
• based on probabilities
• risk of missing ‘hot spots’
• landscape-level measures have unclear indicator value
