Dietary Needs of Animals - Wildlife Center · • Value of “bird in hand” • Statistical...
Transcript of Dietary Needs of Animals - Wildlife Center · • Value of “bird in hand” • Statistical...
11/17/2010
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Michael Lachance
Virginia Cooperative Extension
Wildlife Dietary Needs of Native
Plants and Animals
Wildlife Dietary Needs of Native
Plants and Animals
Susan L. Flader
4-H Wildlife Habitat Evaluation Program
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Why Are We Losing Wildlife?
– Loss of Habitat, Habitat Fragmentation• Increasing human population• Urban sprawl
– Other Human Activities• Introduced aliens, commercial hunting/fishing,
predator/pest control, pollution, exotic pet/plant trade
• Which Organisms Are We Losing?– Animals at Top of Food Chains– Habitat Specialists
Wildlife in a changing world
Losers• Passenger pigeon
• Carolina parakeet
• Bison
• Beaver
• Elk
Winners• Fox
• Raccoon
• Coyotes
Collisions with: Year of estimate Mortality estimate low Mortality estimate high
Wind turbines 2009 88,000 320,000
Towers 2008 4,000,000 50,000,000
Power lines 2001 10,000,000 154,000,000
Roads/vehicles 2005 10,700,000 380,000,000
Urban light 2009 31,158,000
Glass 2006 100,000,000 1,000,000,000
http://www.abcbirds.org/abcprograms/policy/collisions/index.html
Birds collected after colliding with buildings, Toronto 2009, by Kenneth Herdy, FLAP
•POPULATION GROWTH MODELS
–Exponential Growth vs. Logistic Growth
•CARRYING CAPACITY - The maximum number of
individuals of a given species that a habitat can
sustain indefinitely.
KCarrying capacity
Nu
mb
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of
Org
an
ism
s
Time
Exponential Growth
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KCarrying capacity
Time
Optimal yield
(1/2 K)
Logistic Growth
Nu
mb
er
of
Org
an
ism
s
Carrying Capacity for Birds
• Dry western Plains 0.5 – 1 per acre
• Cultivated eastern farmland 1 - 3 per acre
• Deciduous eastern forests 1.5 – 10.5 per acre
Kuchler’s Map of Potential Vegetation of the United States.
Digital Atlas of the Virginia Flora
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Plants as part of wildlife diet
Plants parts for
wildlife food
• Fleshy nuts
• Nuts
• Seeds
• Vegetation (leaves,
stems and roots)
INSECTS AND OTHER
INVERTEBRATES
http://www.birdsasart.com/rootjpegs/loggerhead%20shrike.jpg
Vertebrates Analyze local conditions and existing
ecological communities
Though working with lists of indigenous plants
and animals you can avoid planting material
that has no value to species you are trying to
preserve.
Not only plants but invertebrates can benefit
from native landscape restoration
Pipevine Swallowtail
Caterpillar hosts: Pipevines (Aristolochia species), including Aristolochia californica, A.
serpentaria and others.
Adult food: Solely nectar from flowers including thistles (Cirsium species), bergamot, lilac,
common azaleas, teasel, petunias, verbenas, lupines.
Pipevine
SwallowtailEastern
Tailed-
Blue
Caterpillar hosts: Many plants in the pea family including yellow sweet
clover, alfalfa, various species of vetch, clover, wild pea, and Lespedeza.
Adult food: This butterfly has a low flight and a short proboscis, thus is
found at flowers close to the ground which are open or short-tubed.
These include white sweet clover, shepherd's needle, wild strawberry,
winter cress, cinquefoils, asters, and others.
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Wildlife Nutrition
• One of the basic interactions between an animal and the environment is through nutrition ingestion and metabolism of chemicals and
energy that animals need for maintenance and
production
• Food may dictate where a species can live and population density
• Operates through impacts on reproduction and survival
Potentially acts to influence
1. Age at puberty
2. Length of breeding season
3. Proportion of adults breeding
4. Number of ova shed
5. Prenatal and postnatal losses
6. Juvenile and adult survival
Nutrition
Habitat
Cover
Energy (CHO, fat)
Water Food
Protein MineralsVitamins
•Animals differ in part because of their digestive
systems
•An animal’s adaptations enable it to eat and
digest some foods well while inefficient at using
other foods
•Understanding these differences is important in
managing wildlife
Emerald Ash Borer
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An animal’s diet must provide proper nutrients at
the proper time
• Spring/Summer – growth in young animals
– protein, energy, mineral
thus diets switch often to insects in the
springtime
• Fall - increase body fat ; ovulation
– energy
– weaned young need protein
• Winter - Post-rut recovery; gestation
– energy
– maintenance protein requirement
Field Studies
Information gained:
• How, where, when food is taken
• % depletion of food supply
• Stomach contents don’t show environmental impact of animal presence and disturbance, i.e. wildlife damage
Difficulty of field studies
• Skill and experience of observers differ
• Value of “bird in hand”
• Statistical problems
• Lack of voucher specimens
• Stomach content data often needed to exonerate claims of damage
Laboratory Studies
Laboratory studies look at :
1. Crops
2. Stomachs
3. Droppings
4. Caches
5. Cheek pouches
6. Den and nest materials
Collecting and curating food from dead
animals
• Tools
– Sieves
– Forceps\Probes
– Scalpel
– Blower
• Reference material useful when identifying fragments
• Organs removed, wrapped in gauze with water proof label attached
• Vessels with preservative liquids
– Formalin (10% formaldehyde)
– 70% ethyl alcohol
• Bulky contents, soak in formalin and dry out
• Seeds, dry and add insecticide
To understand an animal’s interactions with its
nutritional environment, need to understand its
digestive system
Credit: David Hewitt, for syllabus for college course in wildlife nutrition:
http://users.tamuk.edu/david_hewitt/
Data card for Collected Food Items
1. Name of Species
2. Specimen Number
3. Date
4. Where collected
5. Where killed
6. Hour of death
7. Person making dissection and date
8. Condition of stomach
9. Condition of gullet
1. Percentage of:a) Animal matter
b) Vegetable matter
c) Gravel, etc.
d) Unknown material
2. Contents description area a) Include number of individuals
in stomach by species and
b) Each percent contribution to the contents
3. Person making the examination and date
4. Location of voucher materials
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Investigating Diet Through Post-
Mortem Food Items
Insure an adequate sample• Sample size or number
• Regional differences
• Seasonal differences
•
Data• Weight of animal
• Contents
– Estimated visually
– Measured volumetrically
– Counted out by kind, especially for predators
– Presence/absence
• Best to report by occurrence, numbers, and % of volume
Food habits of more
than 1,000 species of
mammals, birds, fish,
plus important plants as
food researched by U.S.
Fish and Wildlife
Service, based on
extensive stomach
content studies.
300 illustrations, maps.
Animal Groups Covered in Text
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4-H Wildlife Habitat Evaluation Program
http://www.whep.org/•Wildlife Management Concepts
•Wildlife Management by Regions
•Wildlife Management by Species
•Wildlife Management Practices
•Activities
1. Wildlife Foods
2. Interpreting Wildlife Habitat by Aerial
Photographs
3. On-Site Habitat Management Recommendations
4. Wildlife Management Plan
5. Urban Landscape and backyard Habitat Plan
Components of the Wildlife Habitat Curriculum
Wildlife Management Concepts
• Habitat Requirements
• Featured Species
• Species Richness
• Plant Succession and Effects on Wildlife
• Vertical Structure (Layering)
• Arrangement and Interspersion
• Edges and Contrast
• Area Sensitive Species
• Migration and Home Range
• Carrying capacity
• Pond Dynamics and Balance
• Wildlife Damage Management
• Food Webs
II Ecosystem CharacteristicsPYRAMID OF NUMBERS
For any specific location, there are many more plants
than herbivores, greater numbers of herbivores than
carnivores and seldom more than a few top carnivores.
General pattern in nature:
Primary Producers 1,500,000
H 200,000
C1 90,000
C2=1
Grassland (Summer)
Pyramid of Numbers(Individuals per 0.1 hectare)
Temperate Forest (Summer)
P 200
H 150,000
C1 120,000
C2 =2
Plant Succession
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FRAGMENTATION AND EDGE EFFECTAs the human population continues to grow, development
reduces and fragments remaining undisturbed habitat.
FRAGMENTATION AND EDGE EFFECTAs the human population continues to grow, development
reduces and fragments remaining undisturbed habitat.
• Minimum safe forest buffer given as 100 m. (330 ft.).
• For a 50-acre parcel, only 30 acres of “interior” forest
remains inside the edge.
50 acres 30 acres 100 m Edge
Edge Effect
•An edge effect may penetrate to 600 m.
•For a 100-acre parcel, only 10 acres of “interior” forest
would remain.
100 acres 10
acres600 m Edge
Edge Effect
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50 acres
50 acres 50 acres
50 acres
200 acres
100 m edge yields
30 acres x 4 = 120 interior acres
A 300 m edge yields
5.4 acres x 4 = 21.6 interior acres
100 m edge yields
157 interior acres
A 300 m edge yields
88.3 interior acres
Edge Effect and Fragmentation
50 acres
50 acres 50 acres
50 acres
200 acres
If a nesting pair of wood thrushes needs 10 acres of interior
forest habitat to successfully raise a clutch, calculate how many
pairs of wood thrushes will be successful in each of the above
forest woodlots, assuming a 100 m edge; a 300 m edge.
Edge Effect and Fragmentation
50 acres
50 acres 50 acres
50 acres
200 acres
100 m edge = 12 Pair
A 300 m edge = 2 Pair
100 m edge +16 Pair
A 300 m edge = 9 Pair
Edge Effect Simplified Food Web- Wytham Woods, England
Primary
Producers Herbs Trees/Shrubs Oaks Total Litter
Herbivores
Carnivores
Top
Carnivores
InsectsOther Leaf
Feeders
Winter
Moth
Earthworms
Fungi
Voles
Mice
Spiders
Parasites Owls Weasels Hyperparasites
Shrews
Moles
Beetles
Soil
ArthropdsTitmice
Cyzenis
90% of Energy
flows through
detritivore chain!
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A
C
B
D
Plants as part of wildlife diet
Preference by wildlife
• Preferred
• Second choice
• Starvation foods
Other Resources
Humboldt Field Research Institute and Eagle Hill Foundation , “Northeastern (& Southeastern) Naturalist”: http://www.eaglehill.us/programs/journals/nena/northeastern-naturalist.shtml
Natural Resources Conservation Services Programs for wildlife conservation: http://www.nrcs.usda.gov/
Natural Resources Conservation Services
Wildlife Habitat Incentive Program (WHIP): http://www.nrcs.usda.gov/programs/whip/
Natural Resources Conservation Services Pollinator Enhancement Activity (PLT01): http://www.nrcs.usda.gov/programs/new_csp/2010/ranking_period_two/jobsheet_pdfs/plt/10_R2_PLT01_Pollinator_Habitat_Establishment.pdf
Northern Prairie Wildlife Research Center: http://www.npwrc.usgs.gov
Patuxent Wildlife Research Center: http://www.pwrc.usgs.gov/aboutus/