Chapter 13

Water and Other Welfare Factors

what are welfare factors

resources wildlife need that influence survival and reproduction, including food, water, cover, space and special factors

what are the 5 major welfare factors

food

water

cover

space

special factors

how do wildlife agencies often manage populations indirectly

by manipulating welfare factors and resources

why is water important to wildlife

water makes up most molecules in animal bodies and is critical for digestion, thermoregulation nutrient transport, waste removal, joint lubrication, and physiological reactions

what are the three ways animals obtain water

free water in environment

preformed water in food

metabolic water from oxidation of food

what is free water

water obtained directly from lakes, streams, rain, snow, and dew

what is preformed water

water already contained within food

what is metabolic water

water produced during oxidation of fats, proteins, and carbohydrates

which nutrient produces the most metabolic water

fat (1g fat yeilds approximately 1.07g water)

what factors determine water requirements

thermal load

activity patterns

morphology

diet

metabolic processes

reproductive state

water-conservation adaptations

what is thermal load

total heat stress experienced from temperature, solar radiation, thermal radiation, and vapor pressure

which diets may require little free water

diets rich in fruit, nectar, insects, or animal tissue because water needs can be met through preformed and metabolic water

can herbivores sometimes meet water needs without drinking

yes, large herbivores can obtain sufficient preformed water and metabolic water during part of the year

what challenges do arid habitats create

high temperatures, intense solar radiation, limited food, and limited water

what are the two major strategies of arid-adapted wildlife

avoid arid conditions

tolerate arid conditions

what is the major trade off for arid adapted animals

maintaining body temperature while minimizing water loss

what are behavioral adaptations

behaviors that help avoid environmental stress

give two examples of behavioral adaptations to arid environments

activity at night (nocturnal) or twilight (crepuscular)

using shade, burrows, dens or caves

additional examples of behavioral adaptations

eating foods containing more water

resting during the hottest period of the day

changing body orientation to reduce heat exposure

give two examples of physiological adaptations to arid environments

lower metabolic rate

adaptive heterothermy

what is adaptive heterothermy

allowing body temperature to fluctuate to reduce evaporative water loss

body temperatures are often higher during the day and lower at night

what physiological adaptation can reduce evaporative cooling costs

targeted cooling of the brain

give two examples of morphological adaptations to arid environments

longer thinner appendages

light colored fur or feathers

why are longer appendages helpful

greater surface area allows heat loss and reduces heat stress

why are light colors beneficial

they can reflect heat rather than absorb it

what body structures can passively release heat

vascularized horns and bird beaks

what are the four primary routes of water loss

feces

urine

cutaneous evaporation

pulmonary evaporation

what additional source of water loss occurs in female mammals

lactation

how do desert-adapted speceis deal with water loss

they reduce water loss through all routes and tolerate substantial dehydration

what are the three major goals of water management

increase survival and recruitment

expand animal distributions

buffer populations during droughts

what are the benefits of water management

increased abundance

increased habitat availability

improved habitat quality

benefits of conservation concern

what disease-related drawback can occur with water developments

increased disease transmission and pathogen transfer

what water-quality problems can occur

rotting organic material

toxic algal blooms

environmental contaminants

how can water developments increase predation

predators may concentrate around water sources where prey are forced to visit

how can water developments increase competition

they may intensify interspecific competition near water

ex: feral horses excluding elk

what direct mortality can result from water developments

drowning

ex: desert tortoises

what vegetation impacts can occur

trampling

increased herbivory

species composition changes

increased invasive species

what is a limiting factor

the scarcest resource that limits population growth

what is often the primary limiting factor in arid regions

water

when will water management be effective

only when water is the limiting factor

what is cover

any landscape feature that conceals an individual

give 3 examples of cover

forest canopy vegetation

ground vegetation

topographic features such as caves or cliff overhangs

what are 3 benefits of cover

predator avoidance

protection from harsh environmental conditions

reduced harmful interactions with other species

can predators benefit from cover

yes, cover helps predators stalk prey or use ambush strategies

what types of covers were listed

winter, thermal, loafing, nesting, residual, refuge, escape, and hiding cover

what is the key trade off associated with cover use

risk of starvation versus risk of predation

what is the “landscape of fear”

indirect effects of predators that alter prey behavior and habitat use

how can cover affect behavior

proximity to cover often influences willingness to take risks while foraging

what are special factors

species-specific welfare factors needed in small quantities or for short periods

give 3 examples of special factors

salt licks

dust baths

gravel for birds and waterfowl

additional examples of special factors

mud baths for bears

hibernation sites

sandy knolls for prairie chickens

protected sites for reproduction and parturition

why are special factors important

they can strongly influence wildlife distribution despite being needed only briefly or in small amounts