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121 Cards in this Set

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exotics
those organisms introduced into places they have not previously occupied
what bird came into America with no human assistance in the past 50-60 years?
-cattle egret
Why introduce exotic species?
1. aesthetics
2. economic benefits (i.e. nutria, raccoon for fur)
3. sport hunting
4. endangered in native habitat
sport hunting in texas - introduced species
-fallow deer
-axis deer (3800)
-blackbuck (19000)
-Nilgai antelope (15000)
-Barbary sheep (also in CA, NM)
case for introducing exotic game
1. natural habitats lack any suitable game
2. natural habitat with limited abundance of native game
3. modified habitats no longer produce sufficient native game and/or habitat restoration is not practical
Cooperative Foreign Game program - when?
-1948 by USFWS
-state-federal program
purpose of the Cooperative Foreign Game Program
1. Provide fund of ecological and life history data for agencies and individuals wishing to evaluate exotics for release in US
2. discourage exotic introductions when these data suggest that releases might be unwise
3. fill vacant or understocked habitats with foreign species
Leopold in 1940
-said money and hours of effort put into exotics would be better expended on solving problems of native species and their habitats
characteristics of high-risk species/habitats for exotic introduction
-r-strategist
-wide niche breadth
-gregarious, non-territorial
-on oceanic islands
-mountains or deep, extensive forests
characteristics of low-risk species/habitats for exotic introduction
-k-strategists
-limited niche breadth
-solitary, territorial
-continental
-open grasslands or savannas
3 major categories of human impacts on natural environment
1. pollutants
2. inappropriate resource use
3. exotic introductions <--- most permanent and damaging
translocations
-intentional release of animals to the wild in an attempt to:
1. introduce organism to new sites where it did not previously exist
2. reintroduce organism to environment where it was extirpated
3. augment existing opulation that is small by adding some individuals obtained elsewhere
of 80 translocation projects for endangered birds and mammals in Australia, Canada, NZ, and U.S...
-44% were successful
-Griffith et al. 1989
Of 40 taxa of fishes native to NA deserts translocated to 407 sites...
-26% of sites saw establishment of fish
(Hendrickson and Brooks 1991)
15 plant translocations in California
-Only 4 judged to be successful
-Hall (1987)
why do translocation projects fail so often?
-problems that caused population to be gone are still operating
-success often requitres repeated translocations of substantial number of individuals
-may need soft released
-use of captive-reared animals
what is a successful translocation?`
-results in a self-sustaining population
what factors does ecological theory tell us should be important in determining success of translocations?
-number moved is large
-population rate of increase in large
-effects of competition low
-effects of predation low
wild vs. captive raised animals
-wild more successsful than captive raised
-among wild caight, success dependent on source population (high density, population increasing)
for translocation success, no association with:
-number of releases
-habitat improvements
-soft vs. hard release
rank of importance for successful translocations
1. threatened or native game
2. release area habitat quality
3. release area core or not
4. program length in years
5. early breeder/large clutch
6. bird or mammal
7. log number of years released
max number of releases for successful translocation
-bird = 80-120
-mammal = 20-40
ring-necked pheasant translocations
-1881 in Willamette Valley - 10 males and 18 females
-releasing 8-week-old chicks in summer not successul (75% dead after 25 days)
-pen-raised birds bad
impact
-change in a population's natality, growth and/or survival caused by some disturbance
2 types of impacts
primary
secondary
primary impacts
-changes result from disturbance itself
secondary impacts
-change results following disturbance but not because of it
ex. increased human disturbance because of roads
to measure an impact
-necessary to have some form of documentation - best is before and after study, but study with controls and replicates usually costly, long, not possible)
two types of situations involving impacts
-where some form of habitat change could occur
-where some form of impact has already occurred
planning for impacts (impact analysis)
-knowledge of manager
-study: evalation of area (soils, water, plants, wildlife, people)
-synthesis
things that need to be considered when planning for impacts (15)
1. effects of proposed activity on wildlife
2. different effects on species
3. duration of effects
4. scope of effects (extent of area affected)
5. season of activity
6. adaptability of wlf species present
7. sensitivity of area regarding wildlife
8. resilience and tolerance of vegetation
9. habitat diversity and minimum habitat requirements of wildlife species
10. potential for the area's rehabilitation
11. contributory effects (natural changes to communities)
12. consequences and risks assoc. with unplanned events
13. Human population growth
14. accessibility of the area
15. cumulative effects
mitigation
-to make or become less severe or intense
-to moderate
Purpose of mitigtion:
-avoid change in, or reduce negative impact of a change on, wildlife living in an area
types of mitigation
-avoidance
-trade-offs
-techniques to reduce impacts
-reclamation
avoidance
-try to spare areas of interest
trade-offs
-creating suitable habitats for the wildlife that is to be affected by the project
- habitat evaluation procedures (HEP) and HSI models
reclamation
-restore land to a natural, functioning system
-spurred whole field of restoration ecology
only way to be sure to retain large blocks of forest and retain timber harvest is to:
plan at a large scale!!!!!
how much forest should be retained for wildlife?
-2500-5000 acres
5 key spatially fixed characteristics in forest management for wildlife plans:
1. uncommon features (denning areas, springs)
2. existing large patches
3. stream corridors
4. steep slopes
5. links with other forests or natural resource areas
3 more important items for good planning of forests for wildlife (not the 5 key)
6. additional large patches
7. major natural land corridors
8. main routes for people
what should wildlife strategy be in a forest?
-emulate natural forest succession and processes as much as possible at landscape and stand levels
managing for wildlife at a landscape level
-most common approach to timber harvest is a regular pattern of clearcuts and equal-suzed leave strips between cuts
do clearcuts hurt or help wildlife?
Depends on:
-kind of wildlife
-size of cut
-how long to regenerate
-surrounding habitat
size of clearcuts for wildlife
-deer and elk - 366 m wide max in OR and WA, 8 ha with no more than 300 m width in AZ
-75 m for flying squirrels
-97 ha for moose
cuts of greater than 100 ha
-should have uncut shelter patches of 3-8 ha
-or cut in a way that animals don't have to travel more than 200 m to reach cover
smaller clearcuts and special areas
8-16 ha cuts used more evenly by wildlife than larger cuts
-large cuts should contain reserve of 120 m around aquatic areas, mineral licks, calving areas
pattern of cuts regularly spaced
-undesirable - lots of edge but lower forest interior
-use progressive harvest or aggregated harvest instead
-progressive harvest
-see figures
aggregated harvest
-combining small (4-10 ha) harvest units into 1 large unit
-concentrates activities, minimizes fragemntation, reduces edge and roads
causes of sagebrush/sage-grouse decline
-agricultural conversion
-fire and cheatgrass invasion
-suburban development, roads, power lines
-grazing
-hunting (additive)
number of vertebrates killed every year on roads in US
-100,000,000 in 1987
wolves and elk fail if road density...
wolves - greater than 0.6 km/km2
elk - greater than 1 km/km2
average road density in intensely managed forest
-4.3 km/km2
wolf trees
-large spreading btanches from extensive exposure to sunlight
-foresters tend to dislike, tend to be crooked with lots of branches and suppresses development of nearby trees
-keep them - provide mast, cover, nest and perch sites
deeryards
-deer congregate here (80/mi2)
-snow approaches 46 cm + and white-tails can't migrate out of it
2 basic components of deer yards
1. core - softwoods with high crown closure, usually located on south-facing slopes in low areas (wetlands, riparian)
2. surrounding core of mixed hardwoods and softwoods that provide browse
foot loading
weight / surface area of foot
-increased foot loading = harder to get through snow
5 factors influencing white-tailed deer on winter range
1. snow depth and duration
2. abundance and height of rooted forage
3. comopsition and rate of lichen and foliage litterfall
4. quality and quantity of security cover
5. quality and quantity of thermal cover (shelter and food need to be close together)
deer may respond to livestock grazing by:
-changes in distribution
-changes in habitat use
-modification of activity
-alteration in poulation density
factors that affect competition for forage
Cole 1954
1. both spp. must use same area, not necessarily at same time
2. diet of 2 spp. must overlap
3. more than 1 item in diet has to be important to both spp.
4. items have to be shown to be declining in productivity or as part of plant community as result of combined use by both spp.
mule deer diet
-highly variable
-grasses highest in spring, otherwise browse and forbs
cattle diet
-grasses
-forbs in spring and summer
-some browse in fall and winter
partial overlap in forage of mule deer and cattle:
-influenced by drought and grazing intensity, esp. in late summer when forage is dessicated
-on winter ranges, livestock grazing should go prior to snowfall then stop to minimize reduction of available deer forage for winter
best mule deer habitat is generally
-mountainfoothill areas containing topographic variation
-wide variety of plany communities from riparian zones to shrub grasslands to timbered slopes
-offers variety of microsites so deer can be selective
-best protection from winter storms
prescribed fire
judicious use of fire for a constructive purpose according to a management plan
historical uses of prescribed fire`
1. promote flowering of seed-producing plants
2. eliminate harvest residies
3. fertilize fields
4. improve grazing
5. improve hunting or aid in conduct of hunt
6. eliminate weeds
7. locate acorns
8. communication
9. control insects and plant diseases
10. reduce threat/intensity of uncontrolled fire
11. clear land
most widespread agent of disturbance that releases energy and renews habitat
-fire
influence of fire on habitat depends on
1. fire frequency
2. vegetative type
3. fire intensity
4. size of fire
5. timing of fire
6. objective of fire
differences in timing of fire
1. late spring burns detrimental to weedy plants/forbs
2. winter burns promote forb growth more than in spring
3. species that germinate from seeds burn in late summer and fall
influence of fire on grasslands
-production of grass increases, usually short-lived
-nutrient content generally increases for year or two
-small mammals (fire negative, fire positive, fire neutral)
fire negative small mammals
-forage on inverts in litter
-live in and eat dense plant foliage, nest in plant debris
fire positive small mammals
-use habitats open at herbaceous layer
-feed on seeds and insects
-jumping locomotion
birds in grasslands
-small burns better for many species
-prefer heterogeneous mix of grasses and forbs than uniform patch
influence of fire on woody species
-nonsprouting shrubs killed by fire (big sagebrush)
-burn to kill overstory
-spring safest time to burn but time is short (fall risky but more time)
-shrub response varies
-nutrient responses short-lived (N, P, protein = 1-2 years after fire)
influence of fire on forbs
-many spp. damaged by fire
nutritive values after fire
-often increases in new growth
-may stay the same, but if total production increases, result is higher nutrient content per unit area of habitat
influence of fire on forested systems
-burning makes sense in some, not in others
-NOT temperate/tropical rainforests, bottomland hardwoods, or swamp conifers
-clear slash and improve forage for ungulates
-snags should be protected
effects of fire on deer/elk winter ranges
-reduce encroachment of conifers
-stimulate grasses
-spring burns better for resprouting shrubs and forbs
regardless of fire, soil should be:
-wet
-fire will be cool and do minimal damage to roots and rhizomes
sagebrush habitat
-early recommendations were to maintain mosaic pattern, 50-60% sagebrush survival
-now, burning sagebrush no longer viewed favorable
why is sagebrush burning no longer viewed favorably?
1. remaining sagebrush is valued
2. fragmentation of sagebrush results
3. changes in cheatgrass estavlishment makes return of sagebrush problematic
4. short-term benefits vs. long-term benefits
objectives of fire in wetlands
1. make new, green shoots, roots, rhizomes available to geese
2. expose fallen seeds for ducks
3. make wetlands more suitable for ducks and muskrats - eliminate "sour" marsh
4. forms pools and edge for nesting and feeding
"sour" marsh
-flooded and decomposed organic matter
-impenetrable growthq
3 types of wetland burns
1. surface burns (eliminate veg. above water)
2. root burn (8-15 cm dry sediment)
3. peat burn (dry out basin, burn to get deeper pools of water)
how are prairie potholes maintained?
-organic matter at bottom consolidates, depth of water decreases
-fire burns out organic matter or wind erosion removes it
-keeps wetland from filling in with vegetation
of 607 million ha of non-federal land in US
63% in agriculture
-27% cropand
-27% rangeland
-9% pastureland
practices valuable to landowners and wildlife
1. conservation tillage
2. crop diversity
3. organic farming
4. field borders
5. food plots
6. odd areas
7. linear habitats
conservation tillage
-leave residue on ground (20-90%)
-reduces erosion
-hiding, forage value for small wildlife
-fallowing wheat
-some get more pesticides
organic farming
-less tillage, fertilizers, pesticides
-crop diversification, often with livestock
-offers good wildlife habitat
field borders
-planting or leaving narrow strips of permanent grass and legumes around field edges
-creates horizontal and vertical diversity (5-30m)
-ex. conservation headlands in Europe
food plot
-often paid for by state wildlife agency to provide winter food, keep wildlife dispersed, give shelter
food plot specifications
-rectangular to linear, 50-100 m wide
-0.2 to 2.0 ha for birds
-4-8 ha for ungulates
-15 1-acre plots per 500 ha (15%)
-no more than 400 m from permanent cover
disadvantages of food plots
1. concentrates wildlife
2. attracts pests (starlings, feral pigs)
3. expenses
4. for ungulates, need to monitor population and regulate harvest to prevent degradation of native foods
5. in arid areas, failure in dry years, may be of no value in wet years
odd areas
-bare knobs, sinkholes, sand blowouts, gullies, rockpiles, burrow pits, edges of center-pivots
-often permanent, valuable habitats
-add cover, leave abandoned homesteads alone
linear habitats
-roadsides, fencerows, hedgerows
managing roadways
-mow only thin strip along road, leave rest
-full mow every 3-5 years to keep out woody plants
managing fencerows and hedgerows
-minimum of 3 m
-protect from grazing and fire
-retain or plant trees and shrubs
Iowa study in 1983 on fencerows
-12 bird spp. in herbaceous fencerows
-38 spp. fencerows with scattered trees/shrubs
-48 spp. in those with continuous trees and shrubs
objective of wildlife management on rangelands
-improve quality and quantity of forage available for production on wildlife habitat and sometimes for livestock production
what is overgrazing
-loss of biotic and social values by removal of vegetation by livestock
removing livestock
-often slow or incomplete recovery of deteriorated areas without action
-may need to burn, plant, herbicide, etc.
elk
-grazers
mule deer=
intermediate
-very important = grass, forbs, browse in summer
white-tailed deer
-browsers
moose
-browsers
pronghorn
-browsers
bison
-grazers
bighorn sheep
grazers
effects of livestock on ungulates
-altered plant composition
-exert new pressures on range vegetation
-compete with deer and elk
-alter physiolognomic aspects of rangeland vegetation
how does livestock alter plant composition
-high forage value plants reduced in abundance
-grazing disclimax - development remains proportional to stockking rate and duration
livestock competition with ungulates
-sheep, goats, cattle compete with deer especially in winter (all eat browse)
-deer and goats strongest competitors for browse and mast in all seasons
-sheep nd deer may compete for forbs in summer (sheep 65% diet forbs, deer 68%)
-cattle and goats don't compete strongly for forbs with deer
impacts of grazing - general
-indirect impacts may be more harmful than direct impacts
shelterbelts/windbreaks
-human-created habitats resulting from planting rows of trees/shrubs
-used for nesting birds and small mammals year-round, winter cover for birds, deer
guidelinds for managing shelterbelts
1. preserve all existing shelterbelts
2. ensure that space within and between rows is more than 5 m
3. establish shelterbelts more than 0.6 ha in area and contain 8 rows of plantings
4. long and narrow (7:1 or 8:1)
5. discontinue mowing/cultivation to improve structural diversity
6. retain snags, add nest boxes for specific spp.
7. position new shelterbelts near cropland rather than pastureland
8. leave rows of standing crops unharvested or provide food plots adjacent to belts
9. maintain adjacent cropped areas in no or minimum tillage farm systems
10. encourage woody/cultural debris for small mammals
11. control livestock grazing to avoid loss of herbaceous plants understory
12. encourage vertical stratification through herbaceous, shrub, and tree establishment
pastures
-management depends on forage type, type of disturbance, and timing of disturbance
impact of fertilizers on pasturelands
-few problems
impact of herbicides on pasturalands
-no direct effects
-indirect impact on plant food sources and insects that eat those plants
impacts of insecticides on pasturelands
-some kill wildlife, not often
-organophosphorous and carbamates disappear quickly (unlike old organochlorines)
-direct application may cause dieoffs
recommendations for use of pesticides
1. avoid using during nesting season (April - July)
2. avoid using near riparian zones
3. avoid treatments near willife concentration areas
4. avoid treatments during presence of wildlife or in specific habitats
5. avoid using highly toxic insecticides in center-pivot irrigation systems (lack of control of application rates, drift potential)
6. avoid using in non-tilled weedy areas, ditchways, fencerows, burrow pits, etc.
Shelterwood cut
-removal of stand of mature trees over series of cutting over several year period
-encourages natural reproduction under partial cover of seed trees
-grass and brush competition suppressed by remaining shade
-first of these cuts is seed tree cut