How to get more from readings

SECTION 1
Chapter 1

Chapter 2

Chapter 3
Chapter 22
Chapter 4
Chapter 5

SECTION 2
Chapter 6
Chapter 7

Chapter 8
Chapter 9
Chapter 10

Chapter 20

SECTION 3
Chapter 11
Chapter 12
Chapter 13
Chapter 14
Chapter 15
Chapter 16
Chapter 17

SECTION 4
Chapter 18
Chapter 19
Chapter 21

Chapter 23

No animal survives without food and few can exist without cover. Where water is relatively abundant, the acquisition and conservation of nutrients and energy are the driving forces influencing the kinds and numbers of animals living in the area. Those animals best adapted to acquiring or conserving energy will displace the less efficient individuals to sub-optimal habitats where few survive.

1. Food - animal adaptations relating to obtaining energy from food can be grouped into food acquisition, digestion, and behavioral adaptations to reduce predation risk and energy losses
   1. food acquisition adaptations have to do with mouth parts, size, etc.
      1. birds
         1. most have no teeth and have evolved an internal organ gizzard to function as the food grinding organ.
         2. highly specialized bill structures adapted to particular feeding niches (e.g., humming bird bill vs. hawk bill)
      2. mammals
         1. complex tooth development is a distinctive feature of mammals - teeth adapted to grasp prey, shear meat, grind different kinds of vegetation…
         2. different size mouths and jaw articulation adapted to different tasks - grasp prey with great power, chew/grind cellulose rich vegetation, selectively pick individual food items…
   2. digestive systems of birds and mammals (see Fig. 7-1 in text)
      1. physical structures
         1. mouth (see above)
         2. esophagus - usually simply a tube to move food items to stomach
         3. stomach
            1. monogastric- simple bag where acid digestion of food items occurs
            2. ruminant - complex 4 chambered (rumen, reticulum, omassum, abomassum) biological fermentation vat where microbial action breaks down food items before they enter the acid digestion (abomassum)
         4. small intestine extensive absorption tube where most of digested nutrients are transferred into the animals own system
            1. ceca (plural) cecum (singular) occur in some species and are expanded sacks after the stomach on the intestines where further microbial breakdown (digestion) of foods occurs.
         5. large intestine - further absorption
      2. energy - energy needs vary between species
         1. warm blooded animals require much more energy than cold-blooded animals
         2. energy needs vary with costs to thermoregulate which relates to cover and behavior (see below)
         3. seasonal age and sex differences related to growth and reproduction
         4. energy needs increase with activity - (e.g., costs energy to look for food, avoid predation etc.)
      3. carbohydrates
         1. simple sugars are metabolized easily
         2. complex carbohydrates like those found in cellulose and lignin (plant tissues) are very difficult to digest and few species (e.g., ruminants and some others) are capable
      4. fats - have high energy content and are used to store energy in the body
      5. proteins - provide nitrogen in the form of essential amino acids and are required for growth
      6. vitamins - complex molecules needed in small amounts that function as enzymes increasing efficiency of converting foods to energy
      7. macronutrients - sodium, potassium, phosphorus, calcium etc. for which the body has specific needs
      8. micronutrients - other elements needed in small amounts - we are not even sure of the purpose for some of these yet.
2. Ecology and evolution of feeding behavior and defense
   1. co-evolution of predators and their prey. Selective pressure of predation creates prey that are better at avoiding predators which, in turn, creates selective pressure on predators to get better at capturing prey. (red-queen hypothesis)
   2. plant-herbivore interactions are like predator prey.
      1. plants have evolved mechanisms, thorns, growth patterns, toxic substances to reduce 'predation' by herbivores
      2. herbivores have adapted diets and digestive systems to handle plant defenses
   3. Quality of food
      1. nutritional quality of foods varies little for carnivores. However, nutritional quality of herbivore foods varies widely depending upon soil fertility (nutrients in the soil), seasonal growth, and availability (see below)
         1. nutritional quality affects animal growth and reproduction
         2. it also affects population density directly
      2. animals forage selectively, choosing the higher quality foods.
         1. there are differences in diets of animals that are related to the energy requirements for different age and sex classes at different times of the year (see Fig. 7-3 in text)
   4. Quantity of food
      1. not all food out there is truly available to be eaten
         1. things that reduce availability of foods include: growth out of reach of predators, risk of predation (too far from cover), territoriality by other foragers preventing my access to foods…
      2. animal populations can grow to exceed their food supply
      3. overuse of foods reduces the productivity of the food population - resulting in lower productivity after overuse.
      4. food shortages result in starvation and low birth rates, unless some other factor reduces numbers of foragers first.
   5. Responses to food shortages
      1. many species have adapted to short-term shortages and can go days-weeks w/o food.
      2. hibernation is an adaptation to survive winter periods of food shortage and high energy demand by reducing activity and becoming torpid.
      3. where such responses are inadequate, populations usually decline as animals starve, move to look for other resources (often die during such dispersal), and remaining survivors are in poor condition (see below)
   6. Physical condition and nutrition
      1. biologists have used indices of body fat as indicators of animal survival and population condition.
      2. there is data suggesting that animals in poorer condition (less fat) are displaced from suitable habitats by animals in better condition
3. Food management
   1. more complex than 1) determine foods eaten and 2) provide those foods
      1. difficulties in determining foods required
         1. sampling problems
         2. seasonal diet changes
         3. different needs between sex and age classes and between habitats requiring more/less activity to acquire energy to survive.
      2. problems with providing foods
         1. example of ruminants (deer) starving with full rumens b/c couldn't digest the high quality food they were given
      3. costs of artificial feeding - include the fact that it will keep the population at densities that will continue to require artificial feeding rather than reducing #'s to levels that the habitat can support
   2. if the population is too large for its food supply you can:
      1. do nothing - pop will starve, impact its food supply and reach new 'balance' at some lower level
      2. reduce animal population by increased hunting or introduced predators
      3. live-trap removal and relocation ($$$$)
      4. artificial feeding (see above)
      5. habitat modification - 'best' long-term solution. If you can improve habitat making it more productive
4. Cover - Any physical or biological features or arrangement of features that provide animals shelter from weather or concealment from or for predators - - this term has been used too loosely in the literature.
   1. Cover as shelter
      1. protection from extremes of heat, cold, wind-chill that animals would otherwise need to expend energy to survive
         1. vegetative cover protects animals from wind-chill see Fig. 7-6 in text)
         2. physical or biological cover protects animals from too much solar radiation (heat) and/or conserves body heat to protect from cold. (see also Fig. 7-8 in text)
   2. Cover as concealment
      1. animals primary means of escaping predation
         1. animals may hide in physical or biological cover (e.g., rabbits hiding in shrubs, or crayfish in rock crevices)
      2. escape cover may also be steep terrain (bighorn sheep), wide open space (pronghorn), tall trees (roosting turkeys), deep snow (boreal rodents see also Fig. 7-8 in text)
      3. there are special cover needs for breeding animals
         1. nests, broods, neonatal animals have different mechanisms to escape predation that do adults and therefor, additional different cover requirements for the species to survive.
      4. predators also use cover
         1. effective concealment from which to ambush prey
5. Edges and edge effect
   1. edge is the contact zone where 2 or more different habitats come together; ecotone is the area where adjacent communities blend together.
   2. edge effect is the empirically observed increase in the abundance and diversity of species where edges occur.
   3. edge can be inherent (natural) or induced (man-made).
   4. increased interspersion of habitats increases the amount of edge in the area and through the edge-effect increases diversity (species richness and/or abundance) of animals.
      1. this generality does not always hold. It depends upon the kinds of habitats forming the 'edge'.
   5. negative aspects of edge:
      1. Asphalt and bare soil create an edge but provide little valuable edge effect for wildlife.
      2. increasing interspersion by making smaller and smaller patches (which does provide more edge) will eventually create habitats that are too fragmented to support wildlife populations (see also Chapter 21)