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Biodiversity
Genes, Species, Ecosystems
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Why care about wildlife & biodiversity?
- Diversity of species = diversity of products
- Forest productivity
- Medicine
- Ecosystem Services
- Water & Air Quality (Carbon Sequestration)
- Intrinsic Worth
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3 key questions in managing forests for wildlife & biodiversity
- What type? (stand scale)
- How much? (landscape %)
- What pattern? (landscape scale)
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Forest Values
- Aesthetics
- Recreation
- Wood Products
- Biodiversity
- Spiritual Values
- Clean Water
- Other Forest Products
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Biological Integrity
Native species and populations in their historic variety and numbers interacting in naturally structured biotic communities
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Sustainability
- The maintenance of the potential of our terrestrial and aquatic ecosystems to produce the same quantity and quality of goods and services in perpetuity.
- - social acceptability
- - economic feasibility
- - ecological capacity
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Habitat
- depends on species
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Suitable Habitat
"Habitat" for a given species is habitat where reproduction and survival occur at sufficiently high rates to maintain long-term positive population growth.
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Fitness
- Fecundity: # of young produced per female over a given time period
- Survival: proportion of individuals that live through a time period
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Source
reproduction > mortality
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Sink
reproduction < mortality
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Specialist Predator
single predator species
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Generalist Predator
- Multiple predator species
- uses a large production of available cover types
- human habitation, early colonizers, invasives
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Factors influencing habitat quality
- Cover
- water
- food
- other resources (sturcture)
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Cover
- conserving energy
- escape from predators
- nesting, denning and roosting habitat
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Water
essential but highly variable from species to species
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Factors incluencing key habitat attributes
- conspecifics (reprod., competition)
- heterospecifics (compet., facilitation, predation)
- individual behavior
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Ultimate Resources
quality habitat (food, cover, water) = maximize fitness
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Ideal Despotic Distribution
individual fitness is maintained in the highest quality patches at the lower than expected densities through territoriality
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Density = (suitable) habitat quality
- not really, ideal despotic (forcing individuals into sinks)
- cues used are inaccurate (ecological trap)
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Habitat quality
ultimate resources of habitat are food, cover, and water.
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Proximate Cue
An element of forest structure & composition, or other aspects of the biotic community that an individual uses to predict ultimate resources availability
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Potential Habitat Selection Cues
- Acquired Info
- - Personal Info (individually acquired)
- - info about physical habitat & resources
- - Social Info (Vicariously acquired)
- - public info (performance)
- - location cues (location)
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Species richness
total species at each site
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species abundance
total number of individual species at each site
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Habitat Selection
disproportionate use of a particular habitat in relation to other that are known to be available
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Habitat Use
way in which an individual or species uses habitats to meet its life history needs
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Habitat selection assumption #1
- Location/vegetation type is available to an animal
- - CS: Green Hermit Hummingbird-movement paths
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Habitat Selection Assumption #2
Choice made by animal is adaptive (i.e. is optimal for fitness & not an ecological trap)
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Scale
"spatial or temporal dimension of an object or process" (turner et al. 2001)
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Spatial Scale
- Grain Size (resolution)
- Extent (diff. sizes)
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Fundamentals of habitat ecology and spatial scale
- Landscape, forest stand, gap
- (redstarts and flycatchers; fine scale compete, large scale associated w/ forest)
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Forest Stand
spatial contiguous group of trees and associated vegetation having similar structures & growing under similar soil & climated conditions
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Landscape
Heterogeneous land area composed of an interacting mosaic of patches
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A hierarchical classification scheme for habitat selection
- 1st order selection: physical/ geographic range of a species
- 2nd order selection: home range of an animal/ social group
- 3rd order selection: use of a specific site w/ in the home range
- 4th order selection: procurement of a specific resource from a site
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Home Range
- Area used by an individual/ pair of individuals to acquire the resources it needs to survive & reproduce.
- - is not a territory
- - food, cover & water occur in patches throughout home range
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Habitat component (element)
structure, such as a log, or group of structures, such as understory vegetation, used by a species.
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Change in habitat association across scales
- Black-tailed deer
- local (stand lvl):food
- landscape scale: predation avoidance
- Spotted Owl
- stand scale: sangs
- landscape: mature + edges
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Fundamental Niche
dimensional hyper volume where sp's 1 in the absence of competition wiht sp's 2 is able to persist indefinitely
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Realized Niche
where sp's 1 persists in the presence of competition from other sp's.
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Stand Structure
- physical and temporal distribution of trees and other plants in a stand.
- - described by sp's, vertical/ horizontal spatial patterns, or the size of living & dead plants & their parts.
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Structural Characteristics influencing wildlife populations
vertical & horizontal structure, standing dead wood, vegetation composition & diversity, fallen dead wood
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Tree Spacing Influences
vertical & horizontal structure, tree architecture, development of dead wood
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Vertical Structure
- distribution of plants and plant parts in a vertical plane
- 1. diameter classes of overstory trees
- 2. degree of canopy stratification
- 3. development of an understory
- 4. crown differentiation
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Vertical Structure: Large Overstory trees
- Large branches & platforms (marbled murrelet)
- Deeply fissured bark (big brown bat & brown creeper)
- Recruitment of large dead wood
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Horizontal Structure
- Patchiness (Simple & Complex)
- Tools: Lidar (Light Detection & Rading)
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Standing & fallen dead wood
Primary cavity nester (Pileated woodpecker)
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Vegetation composition & diversity
- understory veg. important to a # of wldlfe sp's
- influenced by overstory cover
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Vegetation Diversity Influences Wldlfe diversity
- conifer associates
- hardwood associates
- shrub associates
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Branch Structure
- Supports epiphytes
- hiding cover for invertebrates
- nesting substrate
- forage
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Cavities in Conifers
- usually in bole of dead tree (large dbh)
- usually made by woodpeckers
- oak-associated cavity-users: woodpecker, squirrels
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Anthropods
- Insect diversity correlated w/ plant diversity
- Deciduous sp's support more insects
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Natural Disturbance
- Structure(legacy trees & snags, low tree density (open)
- Composition (herbs & grasses, shrubs, hardwoods)
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Hardwoods vs. Conifers
Branch structure, cavity resource, phenology, reproduction, arthropods
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Effects of Conifer-centric Forest Mgmt
- altered veg. composition
- - alters patterns of food abundance
- - reduces diversity of food resources
- - alters food webs
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Sturcutral + Functional Diversity
hardwood trees, deciduous shrubs & sp's rich understory
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Leaf Mistletoes
- Phoradendron spp
- Bird disperesed seed
- leafy, some scale leaves
- does not deform tree
- Oak mistletoe (p. villosum), Juniper mistletoe (p. juniperinum),
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Dwarf mistletoe
- causes witches brooms in many tree sp's
- interaction: vector seed, food, brooms for nesting, roosting denning, forest structure
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Vector Seed
- Seed is vectored passively, on feathers or fur
- Documented locations of dwarf mistletoe that canonly be explained by animal transport
- Animals are primary mechanism for long-distance spread
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Root disease & wldlfe
- creat snags & partially dead trees
- provides new dead trees
- casue root & butt rot, hollows
- creats gap in forest canopy
- increases shrub & herb cover in gaps
- impacts forest composition & diversity
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Heartrot
- Caused by specialized wood decay fungi
- Do not colonize wounds, occur only in live trees
- Hard outer shell and soft core
- True heartrots create habitat or wildlife: woodpecker
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Stand Development
- change in stand structure over time
- - types, sizes, arrangement of veg.
- - live & dead components
- - may/ may not result in compositional change
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Function of Retention Trees
- Increases species composition and size class distribution of non-timber
- Influences a number of habitat elements
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Oliver and Larson 1990 Stand Development
- Stand Initiation
- Stem Exclusion
- Understory reinitiation
- Old-Growth
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Franklin et al. 2002 Stand Development
- Legacy
- Pioneer Establish
- Canopy closure/biomass
- Maturation
- Vertical Diversity
- Horizontal Diversity
- Pioneer Loss
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Stage 1: Stand Initiation Stage/ Legacies and Pioneers
- - Small trees with shrubs and herbs
- - Growing space available for all trees
- - Trees grow at roughly same pace
- - what grows following a distrubance is influenced by what grew within the area before
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Stage 2: Stem exclusion stage/ Canopy Closure
- Rapid accumulation of biomass
- Intense competition among trees (Density dependent mortality)
- Closed Canopy
- Relatively little understory
- Self thin
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Differentiation
process of trees diversifying in size within a stand, with some individuals becoming larger at the expense of others.
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Stage 3: Understory re-initation/ Maturation
- Herbs, shrubs, and trees seedlings appear and survive, but have low growth
- Low coarse woody debris
- Density independent mortality
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Stage 4: Old growth/ Vertical & Horizontal Complexity, Pioneer Loss
- Large trees, snags and logs
- Vertical structure/ "canopy layers" (epicormic branching)
- Larger gap fromation
- Dominant trees reached average life expectancy for species on that site
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Fire affecting Owls
- High severity fire decreased occupancy and not used by nesting owls
- High severity burns used by foraging owls
- Survival of owls with territories in burned landscapes was lower than outside burned areas
- Colonization rates increased in low to moderate severity burn areas
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Disturbance
any relatively discrete event in time that disrupts ecosystem, community or poulations structure and chagnes resources, substrate availability or the physical environment.
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Disturbance Components
- 1. Frequency (return interval)
- 2. Pattern (size + configuration)
- 3. Severity (i. amount of above ground vegetation removed, ii. degree of forest floor and soil disruption)
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Natural disturbance emulation
Native species evolved under circumstances of natural disturbance
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Categories of Silvicultural Activities
- Harvest
- Site Preparation
- Stand re-establishment
- Intermediate Treatments (vegetation management & thinning)
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Harvest System vs. Regeneration System
- Harvest systems remove wood from a forest as efficiently as possible
- Regeneration / silvicultural systems use the harvest of trees to create the conditions necessary for developement of a new stand
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Stand Density
- amount of the stand covered by trees
- intensity by which trees are competing for site resources
- relative density = carrying capacity of a site
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Stocking
Measure of stand density relative to a specific optimum set according to management objectives
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Even-Aged Regeneration Systems: Clearcut
- Removing all trees from a site either to release existing regeneration or to provide a planting site
- i. Site Preparation
- ii. Planting and vegetation control
- iii. Pre-commercial thinning
- iv. commercial thinning
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Even-Aged Regeneration Systems: Seed Tree
Creation of seed, partial shade
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Even-Aged Regeneration Systems: Shelterwood
Removing trees in stages to ensure establishment of and protection for regeneration.
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Even-aged Regeneration Systems: Continum of Conditions
- Clearcut Seed Tree Shelterwood
- <-------------------------------------------->
- Less Vertical Structure More
- shade
- moisture
- animal-dispersed seeds
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Potential Old Growth
Tappeiner et al.
- 1. Growth rates in old growth comparable to plantations with 50-130 trees
- 2. Self-thinning not common...
- 3. Broad range in ages and sizes of OG stands, Gap formation important in creating irregular pattern
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Truncation of age-class distributions
- not much old forest
- no available habitat for late -seral species
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Matrix Management
- Lindenmayer & Franklin
- 1. Structural retention at time of harvest
- 2. Management of regenerated and existing stands to create structure
- 3. Long rotations
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Rotation Periods
- Rotation Period: the time between regeneration disturbance
- Economic rotation: optimal time to harvest from financial standpoint
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Uneven aged (multiple cohort)
development of forest stands with >3 canopy levels in a relatively small area.
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Individual Tree Selection
- Uneven-age silvicultural systems
- - individual trees are selected and removed from a stand
- gap formation in old-growth forests
- not necessarily "good" for all wildlife or for timber growth
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Group Selection
- Uneven-age silvicultural systesm
- - a group of trees occurring in the same area or patch are selected and removed from a stand
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Short-term responses of songbirds
- Chambers et al. 1999
- 1. Clearcutting
- 2. Two-story stands (spotted towhee)
- 3. Group selection (brown creeper)
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Thinning
Ultimate result may be even or uneven aged stand
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Tree Architecture
The relative size and shape of the crown and bole of a tree
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Low Thinning
- (thinning from below)
- removal of smaller trees and retention of larger trees
- maximizes growth of remaining trees
- Increases light to understory
- increases crown size and branch growth
- W. red backed vole (abundant ground cover and litter)
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High Thinning
- Thinning from above
- removing some (not all) larger trees and retains smaller trees
- increases growth of remaining trees
- increases light to understory
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Proportional Thinning
- thinning of proportion of age diameter classes is the same afer thinning as it was before thinning
- reduces risk of high grading
- increasess growth of remaining trees
- increases light to understory
- Variation
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Landscape Ecology Importance
- 1. Conservation: habitat loss and fragmentation primary cause of species loss
- 2. Understanding Demography
- 3. Evolution
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Ecology
study of the interrelationships between organisms and their environment
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Landscape Ecology
Pattern + Composition <---> Process
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Metapopulations
- A "population of populations"
- - Large patches/ island better than small
- - Close (connected) better than isolated
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Landscape structure
Landscape pattern and composition
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Landscape Fragmentation/ Pattern
- a. patch size
- b. edge
- c. connectivity: movement/ flows (depends on species)
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Causes of Landscape Structure
- A. natural disturbance & succession
- B. Human caused disturbance
- C. Enduring Features
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Landscape Mosaic
objects are aggregated forming distinct boundaries
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Types of Patches
- Remnant patch
- Disturbance patch
- Environmental patch
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Mechanisms for patch/ island effects
- 1. Sampling effect. More area = more species
- 2. habitat diversity effect
- 3. Extinction effects
- 4. Home range size effect
- 5. Edge effects and ecological traps
- 6. Behavioural mechanisms
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Patch Size Consequences
- Large: greater representivity, less senstitivity to stochasticity, less edge, larger home ranges, more neighbours
- Small: greater likeihood of immigration, protect small scattered habitats, fewer neighbours, fewer predators.
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Dispersal
Movement from one breeding location to another
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Natal Dispersal
movement between natal area and area where breeding first takes place
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Breeding dispersal
movement between two successive breeding areas
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Why Disperse
- Individual level: reduce chance of inbreeding, avoid competition, habitat quality and mate improvements
- Population Level: reduce inbreeding, species response to changing environments, metapopulation stability
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Functional connectivity
- Behavioral responses of an organism to landscape elements
- - contributing factors (mortality risks, movement patterns, boundary crossing behavior)
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Structural connectivity
'habitat' contiguity measred by analyzing landscape structure independent or organism attributes
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Structural retention
- Structure = more rapid colonization
- Movement through stand
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Corridors for connectivity
- strips that differ from their surroundings
- biodiversity protection
- water resoruce management
- agroforesty
- community cohesion
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Roles of Corridors
- Reduce stochastic extinctions
- Maintain genetic diversity
- retain ecological processes (pollination, seed dispersal)
- Gradients rather than categories
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CLAMS
Coastal Landscape Analysis and Modeling Study
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Features of Bioregional Assessments
- Delineated by natural processes / units
- Landscape / Watershed Scale
- Integrate ecological, social, and economic conditions
- Precede detailed planning and implementation process
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Hierarchical Habitat selection
Geographic Range --> Hmoe range --> Resource Patches --> Food and Cover
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Alternative Forest Policies
- Base Case = keep doing what we're doing
- NFT = no thinning on federal lands
- REM = increased leagacy retention on private lands
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Population Viability Parameter (RAMAS)
Fecundity, Survival, Dispersal
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Adaptive Management
Policy/ Hypothesis, Implementation/ Experiments, Monitoring, Evaluation
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Triad Approach
Forest Reserves and intensively managed areas within a landscape matrix managed by silvicultural systems derived from principles of ecolgical forestry.
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Triad Advantages
Public acceptability, green accounting value, having our forest and harvesting too, spatial advantages, adaptive approach to zone allocation, zone treatment dependent on values, complex implementation, time to results, not a panacea, effective communication.
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Triad disadvantage
- Ignore biodiversity
- Public pressure
- no-management ecological reserve zones
- remaining matrix lands are not also managed under an ecologically sustainable framework
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Land Allocations
- Zoning
- Existing Reserved Areas
- New NWFP Reserve system
- Areas available for timber harvest
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Aquatic Conservation Strategy
Restore and maintain watersheds and aquatic functions and systems by understanding the landscape.
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Priority Changes
- young stand thinning
- road decomminssioning
- stream restoration
- fuel reduction
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