Habitat

habitat

• the resources and conditions that produce occupancy (survival and reproduction) by a given organism

• occupancy does not necessarily mean reproduction

• food

• cover

• water

species specific habitat

• relates to the presence of a species to physical (abiotic) and biological (biotic) characteristics (more than just vegetation)

abiotic components

• water

• soil

  • Where soil quality is highest, there is often conflict between wildlife and agriculture

energy

• Released when large food molecules are broken apart

• Measured in calories

• Uses of energy

  • Heat: 

  • Mechanical energy: muscles

  • Construction: replace old or make new cells

Foods with the highest energy values:

• Fats highest (9.45 kcal/g)

• Proteins (5.65 kcal/g)

  • typically the most important

• Carbohydrates (3.96 kcal/g)

basal metabolic rate

• at rest and not thermally stresses

• higher in small animals

• activity requires 2-3 times the BMR

surface:volume ratio / energy requirements

• small animals

  • require more energy due to loss of heat

  • greater surface:volume ratio

  • a lot of surface area

• large animals

  • more body mass as compared to surface area

  • Larger the body and more insulation—lower the metabolic rate

• mammals

  • require more energy than birds

  • small birds have substantially higher energy needs

TNZ (Thermal Neutral Zone)

• area in which we do not need to expel additional energy to cool ourselves off or warm ourselves up

• Above or below the TNZ, more energy is required to warm or cool the body

ways of dealing with extremes (4)

• Standard 

• Putting on weight or thicker coat of fur

• Avoidance of extremes or reduction of energy needs

• Use of habitat

cover def + 4 type

• any features that provide shelter from weather or concealment from or for predators

• Winter cover

• Loafing cover

• Thermal cover

• Escape cover

wildlife management and cover

• Can manage for cover, but managing for one species may negatively impact other species

• Managing forests, with representation of all successional stages, enhances species diversity

ecotone

place where two habitats meet

species that require large tracts of unbroken habitat may not do well when there is extensive edge

edge effect

• wildlife species diversity may be greater than in each habitat separately

• edge species are generalists

• predation higher at edge

• species that require core habitat may be negatively impacted by edge effect

  • clear cutting is a negative for them

nutrition

• process of procuring and processing portions of its external chemical environment for continued functioning of internal metabolism

• sources of nutrients and energy

order of bird digestive tract

• esophagus

• crop

• proventriculus

• gizzard

• small intestine

• large intestine

  • caeca

• cloaca

Liver

Short in meat-eaters, long in herbivores

Cloaca

• short chamber that accepts material from:

  • Intestines

  • Kidneys (uric acid)

  • Reproductive organs (eggs/semen)

Unlike some birds, mammal digestive tracts do not seasonally change with food habits

Meat or digestible diets require shorter tracts

• meat protein quality does not vary as much 

• carnivores are more concerned about quantity 

Herbivores have much longer tracts

• harder to break down plant matter

  • protein content is the most important 

  • proteins are essential to amino acids

foregut fermentors

Ruminants (cud-chewers) have a stomach that is divided into 4 chambers

• can digest plant fiber better because of the complex stomach

  • Time consuming process

  • Nutrients lost from urine, belched as methane, lost during fermentation, and just general energy lost in transformation

  • take longer to produce waste

hindgut fermentors

Non-Ruminants have simple stomachs, but enlarged ceca and large intestine/colon where bacterial fermentation takes place

• Hindgut fermenters have few barriers to food passage, and have a high capacity of food intake rates

  • Eat more, get less out of food, defecate more

feeding rate

• Time it takes an animal to consume forage and for forage to pass through the digestive system are significant factors affecting nutrient assimilation

• Feeding rate is related to plant density, and bite size by the animal 

Foraging in herbivores also influenced by

• Gut capacity (physical restrictions of the digestive tract)

• Digestive kinetics

• Toxicity of plants 

carbohydrates

• Includes cellulose, starches & sugars

• Carbon, hydrogen & oxygen

• Simple sugars are metabolized for quick energy

• Plants contain large amounts of carbohydrates

fats and oils

• Carbon & Hydrogen, fewer oxygen atoms than carbohydrates

• Twice the energy of carbohydrates, but slower to digest

• Fat deposits in body serve as storage depots for energy

proteins

• Nitrogen (in form of amino acids-NH2 groups), in addition to carbon, hydrogen & oxygen

• Energy level is similar to carbohydrates

  • but amino acids are essential to cell reproduction & help build enzymes that are needed for nearly all chemical reactions in the body

vitamins

• Complex molecules that function as enzymes in body 

• Small, but essential, amounts required

minerals/macronutrients

• Includes several minerals & dissolved ions 

  • sodium, potassium, phosphorous, calcium, magnesium & sulfur)

plant toxins and coevolution

• Among herbivores: plants have developed defenses

  • (secondary compounds—not essential to the plants metabolism, purely for defense)

• Animals are also evolving to cope with the defenses—coevolution

  • Reciprocal selective pressures operate during coevolution, making evolution of one species at least partially dependent upon evolution of other species

pine squirrels and conifers

• Squirrels can strip a tree of cones—no cones, no seeds

• Trees counter squirrels:

  • Hard to open cones

  • Fewer seeds/cone

  • Less-nutritious seeds

  • Drop seeds early 

• Squirrels counter trees:

  • Cones selected for # of seeds

  • Stockpile cones 

food quality

• Herbivores--forage quality varies by season and availability of foods that vary in quality—both quality and quantity of food important

• Supplementation, to acquire essential elements of diet

• Carnivores don’t experience such variation: quantity, not quality, the issue

food quality and soil fertility

• Energy content per gram of food

  • Commonly expressed as % protein or N on a dry mass basis

• Positive relationship between population density and soil fertility

poor nutrition and reproduction

• Poor nutrition—poor reproduction & poor disease resistance

  • Distributions may be explained by deficiencies

• Selective feeding (“hungers”) may partially compensate for scarcity of nutrients

  • a hankering - but it’s more based on what they actually need

age and diet

• young animals require more protein

  • milk

    • big provider, but needs supplementation at time

mallard duck age: related changes in diet

• Protein essential for early growth and development

  • Ducklings eat insects when young

  • Protein needed for growth

• Switch to herbivory completely by fledging

• switch back to carvivory when producing eggs

dealing with food shortages (3)

• Tough it out—

  • do nothing, live off body reserves

• torpor

• Hibernation-

  • seasonal reduction in metabolism and body temperature

condition indices (4)

• Body mass

• Body fat

• Fecal analysis

• Blood Analysis

how can we study wildlife nutrition (4)

• Direct observation

• Stomach contents

• Fecal samples

• Stable isotopes

planting food plants

• In some circumstances, food plants can be propagated for wildlife

  • Should be plants adapted to local conditions

  • Should be coordinated with other land-use activities (e.g. logging, control burns, mining, road construction, etc.)

  • Sharecropping with local farmers—contracting land for wildlife

poor forage managment responses (5)

• 1) Do nothing

• 2) Reduce population

• 3) Live-trapping, removal & relocation

• 4) Artificial feeding

• 5) Habitat modification

water and its management

• Water is an essential nutrient, 3 sources:

  • Free water (streams, ponds, rain, snow, etc.)

  • Preformed water (in food)

  • Metabolic water (produced by animal via oxidation of organic compounds)

• Wildlife managers may add water to habitat where it is limiting

  • Benefits not well documented

water catchments: def, ben, cost

• Harvest rain or snow, storing water for later use by wildlife

• Potential Benefits

  • Increase available habitat

  • Improve habitat quality

  • Recovery of threatened or endangered species

• Potential Negative Impacts

  • Increase disease transmission

  • Increase predation

  • Over-foraging of vegetation near-by