Transcript Home range

What about the predator?
• Again, seem to forget the predator in all this.
• What adaptations do they have to try and
make attack successful?
Anatomy….
• Obvious that they have the tools
• Specific to each species as to which are used
more
• But what about the behaviors?
• Are there things they can do to improve
chances?
Obvious ones
• Cursorial vs ambush
• Solitary vs group or pack
here
Attack points
• Some prefer the back end (usually cursorial
ones)
• http://www.youtube.com/watch?v=CT_3QiW
Qh8M
Attack points
• Some (stalkers) prefer the back or head region
• http://www.metacafe.com/watch/yt7HogWIpfLjc/cougar_and_cub_hunt_a_deer/
Aerial predators?
• Owls tend to swoop in low
• http://animal.discovery.com/videos/killerclips-birds-of-prey-owl-mouse.html
• Hawks tend to hover higher
• http://video.yahoo.com/watch/4577360/1225
5461
More
• Falcons
• http://www.youtube.com/watch?v=j3mTPEuF
cWk
• Each species has specific attack style.
Summary
• Two player (often more!) evolutionary game
where behavior is the game plan!
• Again, a prey’s behavior will revolve around
trying NOT to get eaten.
• A predator’s around trying TO eat the prey
Why doesn’t the predator WIN?
If responses by prey are countered by
evolutionary responses of the predator.
Eventually, predator could win!
• But remember, which has more to lose?
• A predator loses a meal
• A prey loses its life!
• Selection pressure is greater for the prey!
What next?
• The stage: Habitat is where it all happens
• Talked about use of habitat in reference to
foraging theory, landscape of fear.
• But again in more theoretical aspects
• Now look at some of the more detailed
behaviors associated with habitat use.
• Chapter 13
What First?
• Had talked about animals selecting habitat for
resources, for safety, etc.
• On the landscape scale, ample data indicate
individual animals will use the same area
repeatedly.
Example
• Coyote locations over 9 weeks
• This we commonly refer to as the Home range
Burt 1943
• First proposed the concept and that an animal
did not roam randomly around.
• “Home range then is the area, usually around
a home site, over which the animal normally
travels in search of food.”
• “Even then I would restrict the home range to
that area traversed by the individual in its
normal activities of food gathering, mating,
and caring for young.”
Home range behavior
• So animal is purposely restricting its
movements.
• Reasons?
• 1) Nest site: becomes a central forager,
efficiency of food gathering decreases with
distance
• 2) becomes familiar with where food is
distributed, phenology of food abundance.
But still…
• If don’t have central nest site (many animals
don’t), why restrict your activity to a given
area?
• Would possibly lead to over use??
• What other reason?
Predation risk
• Again, trade off between foraging and safety.
• Might be advantageous to move randomly
over a large area
• But, with each new area, unfamiliar with the
landscape of fear!
• Where are the safe and risky areas?
• Best to stay in the “hood” than wander.
How big should the “hood” be??
• Ok, if your going to stay in one area, be it for
familiarity with resources or predation risk…
• How big of an area should it be?
• Age old question:
• Some say related to size of animal:
Regressions of various mammals
Looks good but….
• Feral pigs: size difference in a species adds
variation.
Some say it is density!
• Same study found inverse relationship
between home range size and density.
Others?
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Some say it is latitude
Some say it is productivity of habitat
Both related to either mass or density so….
But doesn’t get at the basic question of why is
it as big as it is!
• Indicates maybe resource levels but does not
hold as well.
• How about fear!!
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here
Predictions
• 1) If it is fear, then home ranges of each prey
individual should have similar range in
makeup of risky vs safe areas.
• 2) across species should also see relationship
• Should be trying to carve out an area that
provides sufficient safe areas or refuges.
• To my knowledge this has yet to be tested.
What about the predators?
• Best to learn the landscape of opportunity.
• Again, not where prey most abundant but
where they are most vulnerable.
• As with prey, home ranges of each should
have sufficient successful habitat
• Prediction: home range size will be a function
of quantity of successful hunting habitat.
This we tested!
• Puma edge talk.
So that is large scale use
• Within home range we are saying that animals
are selecting certain habitats more than
others.
• How do we know they are selecting?
• What is our reference point??
What should we use as a model?
• IF we say that habitat use is resource based
• That is, a habitat with a higher level resource
should be used by more individuals
• The question becomes what would the
distribution rule be?
• Ideal Free Distribution (IDF) suggested model
What is IDF model?
• Simplest is two patches (H1 and H2), each
with different resource levels (R1 and R2)
• R1 is five food units/minute
• R2 is three food units/minute
• If N individuals can move freely between the
two patches, how should they distribute
themselves? (how many in H1 and How many
in H2?)
The prediction
• IFD predicts that: equilibrium distribution of
individuals into patches should be that
distribution at which, if any individual moved
to the patch she was not in, she would suffer a
reduced payoff!
• In this case, it is if any individual moved from
H1 to H2 or visa versa, it would obtain fewer
resources as a result of its move.
Visually what does this mean?
• Imagine animals moving around at will. The
more enter one patch, the less
resource/individual/time is available.
• If one moves from H1 to H2 and If it can do
better in H2, it will stay. If not, no reason to
move!
• Means they all assess their relative harvest
rate compared to each patch and don’t move
anymore when they can’t do better.
Mathematically?
• Equilibrium is when R1/N1 = R2/N2
• When per capita intake rate in both patches is
equal
• Example: simplest is 5/5 = 3/3,
Does it apply?
• Laboratory situations where resource level
only selection criteria: fairly good.
Results
• Separated out as predicted AND changed
when ratio changed
In the field?
• Again, under controlled conditions.
Results
• When food was 1:1, ducks were 1:1, when
food was 2:1 the ducks were 2:1
Conclusion
• So, when resource levels are the only
consideration, seems to work
• Conclude that ALL ELSE BEING EQUAL, ideal
free distribution will predict distribution of
individuals over landscape: they will be
distributed according to the relative
abundance of food resources in each patch.
Is all else being equal reasonable?
• Again, as with many models, this is the
starting point.
• IF you do find a IFD, then all else is equal and
resources are major factor
• In fact, rarely is all else equal and IF you do
not find an IFD, that indicates other factors
than resources are important.
What other factors?
• Microclimate: can affect foraging strategies
• Resource types: remember each species has
ranking of food types so gross resource
availability may not be appropriate
• Predation risk?
One last one
• Territoriality: you may not have a choice of
where to go!
• What is it? Occupation and defense of a
particular area or areas within a habitat.
• How does it differ from home range?
• In some species it is the same!
• They defend their whole home range area
Territoriality
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In many, it is a subset of the home range
In many, it is not evident.
How do we distinguish?
Home ranges can overlap extensively
Territories do not.
Advantage?
• Home range is to better know the
environment you live in: resources, predation
risk
• Territory is to defend those resources!
• Function of a territory is to provide owner
with exclusive access to food, mates, safe
habitat, etc.
Costs of territoriality?
• Once you choose to defend an area for its
benefits, it will cost you!
• First, it doesn’t come easy.
• If you figure it is worth defending, others will
too!
• So defense of a territory has to be vigorous,
no half-hearted measures, if so, you will lose!
Time commitment
• Territorial defense is a 24/7/365 time
commitment.
• You have to expend a lot of time non-contact
time making sure no one is trying to take it
over!
Here
Is it worth it?
• No brainer: must be, if not would not see this
behavior.
• Real answer is: it depends on what you are
defending.
• If the resource is mating opportunities, then
YES it is often worth it.
• Majority of territorial behavior is related to
sex
Mating territories
• Mentioned before, males of many species
stake out courting and breeding territories.
• Leks to song birds all actively defended
“space” or territories
• Male mountain lions
• Size defended depends on mating systems
Resource territories
• Here it becomes less evident.
• Many herbivores, resources are not restrictive
and so see little resource territoriality.
• Will see a little more in predators.
• Here they may not be defending the resource
but the habitat in which to catch the resource.
Predatory resource territoriality
• If a predator’s ability to catch its prey declines as it
enters a patch (prey become more aware), needs to
use its area in a manner where areas “rest” long
enough for prey to drop their guard.
If others use the patch?
• If other predator visits patch, becomes more
difficult.
• Prey will have a higher level of vigilance than
predicted.
• So defend use of patches to “manage” fear in
prey.
Summary
• Defending an area (territory) has its
advantages.
• Costly but if resource worth it, will be done.
• Usually most common related to
reproduction.
Establishing a territory
• Ok, territory is good but how do you decide
what area to defend?
• Limit ourselves to none breeding territories
• Evidence indicates that Learning behavior
figures in.
Learning and territory establishment
• Example is juvenile lizards (Anolis aeneus)
• Found that juveniles established territories
based not on food resources but on
temperature AND safety from predation.
• How did they determine an area had these
requirements?
Observed others?
• Prediction was that juveniles observed other
older lizards and learned which areas were
more suitable.
• Experiment: allowed them to watch others in
territories and see another area where there
was no lizard.
• Removed occupant and then gave test animal
opportunity to select.
Results?
• Arrived sooner to pre-occupied areas
• And used them more
So learning from conspecifics!
• Strong visual component: IF test animal did
not see occupant before, no preference.
• Referred to as: Conspecific cueing.
Sharing your territory??
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Seems contradictory, it’s yours, why share?
Obvious male-female sharing
Other times?
IF you have enough resources to share, you
might allow an intruder IF it shares defense
duties.
• Case study: Pied wagtails
Satellites
• Defends a circuit where it looks for food.
• IF food abundant enough, allows satellite
individuals.
Flexibility
• What this demonstrates is just how flexible
territorial behavior is.
• Can be confusing at times because of the
variation among AND within species!
• Add to this the size variation
• How to best visualize it?
Territoriality is a matter of scale
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Looking at social behavior expanded
Personal space to territorial space
No species is indeed then truly solitary
Live imbedded in a social system established
by interactions among members.
• Could be daily interactions as in truly social
species
• Could be occasional interactions among
territorial occupants.
• Pack is territorial behavior condensed
• Solitary behavior is social behavior expanded.
• What determines if you have a large or small
“territory”?
• Resource abundance, Resource availability,
predation risk.
• What is required to extract a living AND stay
alive!
Migratory behavior
• Now lets contrast home range and territorial
behavior with Migratory behavior
• Though many species do have home ranges
and even territories, they don’t stay in them
all year.
• May be a relatively short distance (deer
moving up or down slope) or from pole to
pole (arctic tern)
Birds and more
• Most striking are the annual bird migrations.
• Waterfowl most obvious but MOST birds in
northern hemisphere migrate.
• Many mammals do it but not as extensive,
unless we include the oceans!
• Fish!! In and out of the oceans: salmon
• Insects: butterflies.
Birds as an example
• Early naturalists thought migratory birds just
hibernated!
• 5 billion land birds migrate from Europe and
Asia for Africa and similar numbers leave
North America!
First Patterns
• In general movements are intercontinental or
at least multi-national movements northsouth
Examples of migration patterns
How do we know?
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Banding programs in winter and summer ranges
Doppler radar shows flocks of birds moving
Feather chemistry
Carbon 13-12 ratios in feathers
Will reflect ratio of food source where grew
feathers
- Compare summer and winter areas, match
feathers to sources of origin.
General patterns
• There are certain migratory routes that birds
will use for generation after generation
• In North America, they primarily follow
mountain ranges and coast lines/Mississippi
river: waterfowl follow major flyways.
• In Europe and Asia, strong east west segments
because of e-w mountains and Mediterranean
sea.
North American Flyways
Western Hemisphere routes
General patterns
• Many fly over oceans and so routes vary.
• Characteristics of routes taken
- Easiest flying (not crossing mountains, bypassing large bodies of water, more thermals
on land)
- Easiest: leads to bottlenecks: narrow areas
over water, Straits of Gibraltar.
- Dependent on individual species
General patterns
• Daily timing of flights
- General pattern is to chose times when travel is
safest and most rapid.
- Depending on species: lot migrate at night
- Why? Safer for sure, also air can be more stable,
cooler (heat loss)
- Altitudes: low mostly (700-800 m)
some high to avoid turbulence Up to 9000 m
recorded.
Altitude of flight
Migration distances
• Vary in length relative to how far they need to
go to find the right conditions (some
individuals of a species DON’T migrate)
• Many go 100’s, even 1,000’s of kilometers
- Arctic shorebirds > 13,000 km to South
America
- Bar-tailed Godwit 11,000 km nonstop!
- Blackpoll Warblers nonstop (> 80 hrs) over
Atlantic from East coast to South America
Migration Distances
• Migrants from Europe fly 1,100 km across
Mediterranean Stop and rest and then fly nonstop 1,600 across Sahara Desert!
• Besides trying to impress you, what do these
migration distances tell us?
• VERY energy intensive
• So why do they do it??
Why migrate?
• Go back to beginning of class:
• Need to consider two absolutes:
- The day (24 hours or 199 hours) still time from
sunrise to sunrise (or any other point)
- remember marking time artificial: hours !
- The year : 365.25 days to complete trip
around sun.
Annual Cycles
• So, the two absolute time frames are Cyclic!
• Start at one point and you eventually get back
to it.
• Time may be linear but it passes in a cyclic
fashion.
Annual Cycles
• Annual cycles involved in responding to
annual changes in environment because earth
is a ball traveling around the sun.
Annual Cycles
• Review: position in orbit imparts specific
conditions
Result
• Again, related to physics of earth placement
and movement.
• Some parts of globe freeze!!
• Most animals have to adjust
• Migration is a way to take advantage of these
changes.
• Many species, whole life is spent going from
“winter” to “summer” territories.
Annual cycles
• Related to light length
• Even in tropics, but
here it is food availability.
Thursday 4:00
Illick 5
• The ecology of Fear: A unifying paradigm in
ecology??
• Dr. John W. Laundré
Annual Cycles: how do they
know??
• Two main changes:
1) Day to night (24 hour) Circadian rhythm
2) Length of day (Annual or annual rhythm)
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here
All organisms, plant and animal have
physiological controls for changes that occur.
These controls are influenced by circadian and
annual rhythms: we have “biological clocks that
sense changes in rhythms.
Biological clocks – where?
• Pineal gland on top of brain in birds
• Well developed gland with photosensitive
cells.
• Direct production of Melatonin, regulatory
chemical.
• Most pronounced is Circadian responses
- Daily light level, twilight, triggers switch in
physiology.
Circadian Rhythms
• Intrinsic rhythm of 23 hours! Oops!
• Need to synchronize with external cues
Zeitgebers or “time keepers”
• Experiments show value of Zeitgebers, if not,
lose synchrony.
Annual rhythms
• Endogenous rhythms of approximately one
year
• Photoperiod (length of day)
• Photoperiodic control systems use 2 types of
info:
1) Internal circadian cycles help bird measure
day length
2) External environmental-light stimulates
neural receptors.
Sensing annual changes
• Circadian rhythms have limited period of
photosensitivity per day.
- Longer day length means more overlap of light
with this period, which can be used to
measure day length.
• Also have receptors in hypothalamus in brain,
pineal gland, and retina!
- Longer day lengths are sensed and produce
changes.
How produce changes?
• Neurohormones! Sounds like science fiction!
• Light stimulates cells to produce and secrete
them.
• Master hormones mostly located in pituitary
gland.
Known Hormones
Why Migrate?
• So the why is related to food and
temperature, escaping cold temperatures in
north….but
• Why go north to begin with?? Why not stay
south??
• So is not as simple as we thought!
• What factors do they use to decide?
Why Migrate
• Still some doubt but there are the ideas.
• Based on the obvious that benefits of
migration must offset risks and costs
• Main idea is that birds aren’t heading south to
avoid cold
• Tropical birds heading north to take advantage
of long light/abundant insects.
Why Migrate?
• Large expanses of land in the north so less
competition- waiting list in tropics!
• Reduced predation: If a predator has prey
species year round, can specialize. If only for a
short period of time, will be less predators and
less specialized in a particular migratory
species.
Why migrate?
• IF you are a northern bird (some are yearround residents in some locations), actually
spend less energy migrating south (energy of
migration vs thermoregulation
• Key is “some locations”: If winters severe
enough, migration is better, if not, might be
worth staying.
Sexual differences
Differential migration
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Young migrate greater distance than adults
Males less distance than females
Why?
Again balance of needs
In Dark-eyed Juncos, Young males least, adult
females greatest: Sex advantage for young
males- return first for territories.
Why???
• Resource based but not a simple answer.
• More animals taking advantage of abundant
summer resources than avoiding harsh
winters
• They would consider themselves southern
residents who vacation in the north rather
than visa versa.
How do they do it?
Navigation
• How do they know where to go?
• Again use birds:
• Can return to the same marsh/tree etc. after a
trip of 1,000s of km!
• Holds for both ways!
• What cues do they use?
Navigation
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What do they need to know?
Compass direction: what is N/S/E/W
Where they are relative to goal
How would we do it? Direction: compass easy
Latitude –stars (what a sextant is for). Angle
we are relative to north star changes as go N-S
• Longitude – a little more difficult need to
know time of day!
Navigation
• So how do birds do it?
• Actually a mixture of methods, a
“complementary and interactive toolkit”.
• Includes a variety of mechanisms and abilities
• Consider each.
Navigation
• First is “visual landmarks”
• Animals are no dummies as we have seen. So,
like us, when traveling overland, use
landmarks.
• Why waterfowl and many others have specific
routes, coastlines, rivers, mountains.
• Even modern railways/highways seem to be
used.
Navigation
• However, does not explain how they get over
water or on foggy days/nights!
• Sun compass use position of sun to
determine direction.
• Experiments in circular cages showed birds
were directional in their movements when
could see sun. When could not, did poorly.
Sun compass
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Use of sun requires knowing time.
Do they?
Test with starlings showed Yes!
Could trick them by using “sun”
that did not move!
- Also worked when changed
internal clock.
- So yes can tell time!
Navigation
• Star Compass: If flying at night can use stars
• Do they?
• Planetarium experiments
demonstrated YES.
-familiar with most
constellations.
Navigation
• Geomagnetism Sensing the geomagnetic
fields.
• Can they do it? Experiments with magnets
tied to heads demonstrated that yes can do it.
• Respond to angle of inclination of magnetic
field, not just north vs south!!
• Respond to changes in intensity of magnetic
field!!
Navigation
• Odors: Chemical odors can be detected by
some. (sensitive sailors could “smell” land).
• Twilight cues: Use setting sun to determine
west. But also use polarized light that runs NS to determine direction.
Zugunruhe
• The onset of migratory activity is characterized
by a restlessness commonly referred to as
Zugunruhe
• Hormonal in nature as we saw and does seem
to be genetically controlled.
• Demonstrated via selective breeding
experiments
• Could alter when this occurred.
Summary
• Many environment is changeable over most of
the planet
• Many species respond by moving from one
area to another and back again, Migratory
behavior
• Energy intensive but benefits can be
substantial.
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Summary
• For birds, benefits seem to be related to
accessing a seasonally abundant food supply,
especially for reproduction
• Hormonal control under the influence of day
length.
• Migration involves navigational behavior
• All forms used: visual to magnetic fields.
• Constitutes a significant part of their lives.
Dispersal behavior
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Other form of movement.
Usually unidirectional
Usually young but old may exhibit it also.
So usually from natal area to new home range
or territory
• Most often males
Dispersal behavior
• Reasons?
• Resource based: greener pastures! From area
of high density to lower.
• Sexually based.
• Some feel it is an innate aversion to
inbreeding (young males avoiding mating with
their mothers or sisters)
• However often find males mating with their
daughters
Inbreeding avoidance?
• Genetically equal so hard to imagine a young
male resisting inbreeding but then engaging in
it as an adult.
• Rare that young male will have more will
power than older male!
• More of how we WANT to view the system
than how it really is!
Conflict avoidance
• Another proposed hypothesis for male
dominated dispersal is that young males are
forced out by their fathers or other males.
• Under this hypothesis would predict high
amounts of male-male conflicts, especially
father-son
• This type of aggression is common, sexual
competition is the norm among males
Mechanism
• But why is it the young males that disperse?
• Under the conflict hypothesis, the young
males are….younger!
• No match with father, unless father really old!
• Even if a match for father, other males coming
into area are older, better suited to defeat
father and son!
Resulting dispersal patterns
• Thus young male leaves and continues to
move as long as he gets beat up!
• Either by territorial holders or by other
dispersers over disputed vacant territories.
• Until… enough experience/strength, becomes
the winner.
Dispersal distances in cougar males
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Idaho Data
New Mexico data (approximate)
Frequency
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Home range Diameters
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Summary: Dispersal
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Many young leave natal home range
Predominance of males.
For many it is resource based
For many others it is for reproductive reasons
Most likely driven from home range area by
fathers or larger conspecifics.
• Is a mechanism for colonizing new areas.
Behavioral Conservation
• Last topic to cover is the use of behavioral
ecology in conservation biology
• How do we use what we know about the
behavior of animals in efforts to conserve
their populations.
• Can be an extensive consideration
• Here only touch on some aspects to give an
appreciation as to how important behavior is
in conservation efforts.
Significance of behavior to
conservation
• Conservation biology is relatively recent
• Though conservation was advocated by early
naturalists, e.g. Muir, Thoreau, etc.
• American opted for management rather than
conservation.
• Management: “wise” use of selective species
• Still lead to abuses and declines of undesirable
species
Birth of conservation biology
• Began to realize with management we were
saving the desired species but losing the
structure and function of the systems that
supported them!
• Conservation biology began in the 1980’s,
Soulé a main figure.
• Argued we needed to conserve all species of
the systems.
Focus of con bio
• Multi-disciplinary: ecology, population biology,
population genetics, systematics, etc.
• Develop conservation models, plans, actions
to conserve species, which then conserves
main focus; biodiversity
• PVAs, MVPs, metapopulations: focus on main
reason for biodiversity loss, fragmentation.
Actions
• Dealing with small populations, trying to
recuperate them. (conservation biology is the
biology of small populations; Ne becomes
important)
• Land protection: Parks, reserves, etc.
• Reintroductions
• Captive breeding
• Corridors
• Etc.
Where’s the behavior?
• Unfortunately, in things such as PVAs, MVPs,
metapopulation dynamics, and corridors,
behavior is often left out.
• Why and how is behavior important?
• Look at several behavioral categories we have
covered and see their link to conservation
biology
Small populations
• In all cases, dealing with small populations
• Individual behavior and behaviors among
individuals then become important
What your trying to do is increase flow of energy
through the species.
Two levels: individual; you want the individual to
get enough energy to survive
Population: you want the individual to
reproduce: successfully!
Individual energy gains
• Foraging behavior becomes important
• Area has to provide adequate answers to the
four questions: what, where, how long, and
where to next
Diet choice
• Saw earlier diet choice is a balance between
gains and costs
• Obviously range of what a species eats is
important
• Generalists vs specialists: Behavioral choices
based on gains and costs
• Usually in conservation biology dealing with
specialists: animals with narrow diet range
In either case
• Knowledge of diet AND whether area supplies these
food items becomes important and is direct result of
diet choice.
• Diet switching behavior also important: What are the
“rules” the species of concern follows?
• Type II curve, what is its shape, when will it switch to
second choice?
• Remember it is the abundance of the preferred food
item that determines when to switch.
Significance of this?
• 1) abundance of primary food will determine
abundance of species.
• Why? Lower food items are lower because
they provide less gain at greater cost.
• IF secondary food is abundant and primary
food low, will not have as great of a potential
in increasing the population
Patch selection/residence
• Now know that distribution of food as important as
abundance!
• What is patch structure of area?
• Does it provide adequate choices?
• What are relative patch qualities?
• Juxtaposition becomes important
• Travel times
• Not as simple as providing “adequate” food
resources.
Intra specific behaviors
• Individuals need to interact and how they do
this can impact success of conservation
program.
• Need to know something about competitive
behavior between males.
• For mates: outcomes of male-male
competition has impacts on who will breed
Male-male competition
• Who will breed affects: Ne , genetic
composition of population (Possible loss of
genetic material could be high)
• Example: Bison in the Badlands National Park
• Aggression determines which males breed
• Lineage of more timid males, less able to
defend females is declining
• Knowing this, adjustments can be made (e.g.
separation of two groups)
Other examples
• Infanticide by males: killing offspring sired by
other males: can affect reproductive output
• Hybridization between two similar species:
• Just a few factors about male competition that
would need to be considered
Female choice
• Now know female choices and is an attempt
to increase fitness of offspring
• In small populations, there is less to choose
from!
• This is especially true in captive populations
where we often do the choosing for females!
• Many time why captive breeding can fail or is
less of a success as we hope!
Symmetry
• Saw earlier that morphological symmetry
plays a role in mate choice.
• Environmental disturbances could affect this
symmetry and affect female choice
• Leg bands! In captive breeding, females may
prefer not to mate with a male that has one
but no the other!
Courtship
• As with food resources, areas for courtship
rituals to play out have to be considered
• Very species specific behaviors!
• May have adequate food but if there are no
lek areas, will not have the species there.
here
Mating systems
• Often small populations can have skewed sex
ratios
• Ne will be affected depending on mating
system: monogamous; Ne will be set by lowest
number sex
• Polygynous: Lek system may not be sustained
if there are not enough males OR females!
Parental care
• Again, in species where both parents provide
care, a female may mate (extra pair mating
with male of other female), but chances of
survival of offspring low.
• Lions: one male may do the most mating but
other males (subordinate siblings) needed to
protect from other males; not enough
protective males, system breaks down.
Sex allocation
•
•
•
•
Many species have biased birth sex ratios
This has to be taken into consideration
Example: Wild ass:
Middle aged females give birth primarily to males,
younger and older to females.
• Need females to increase the population
• Released primarily middle aged females!
• Population grew very slowly until middle aged
became older and started producing females!
Dispersal behavior
• Obviously you want population to grow and
increase in range
• This requires dispersal of young, male and
female!
• In many species males primary dispersers
• So may need to plan on helping females!
Dispersal behavior
• Many species have distinct requirements for
dispersal habitat
• Dispersal routes become important
• Bighorn sheep, reintroductions can fail
because don’t know how to get off the
mountain in the fall!
Dispersal distances
• Again, some species will more readily disperse
over longer distances than others.
• This has to be taken into consideration
Inbreeding avoidance
• Dispersal becomes very important in small
populations where you want new individuals
to come in to reduce effects of inbreeding.
• DON’T assume there is an innate avoidance of
inbreeding!
Interspecific considerations
• Predator-prey relations
• Antipredatory behavior
• The landscape of fear/opportunity
Landscape of fear and conservation
• More important than resources, risk involved
in getting these resources
• How can landscape of fear affect conservation
efforts?
• Mentioned before, landscape will consist of
differing percents of risky/safe habitats.
• If area is primarily risky, reintroductions will
fail
What do we need?
• Need that balance between risky and safe that
insures species has enough safe areas to
persist.
• Predator? Often conservation efforts are for
predators
• Landscape of opportunity.
How do you modify?
• Behavior specific!
• Need to identify risky/successful vs
safe/unsuccessful habitat and then plan
habitat modifications that will tip the balance
the way you want.
• Example: desert bighorn and shade.
Ecosystem conservation
• Newer emphasis in conservation biology
• Realize can’t conserve species if we don’t
conserve ecosystems that support them
• Two things: structure: obvious, if we don’t
have the habitat, we don’t have the species
• Function: not as obvious, need to conserve
the function of ecosystems: energy flow
Ecosystem function
• How do we maintain energy flow?
• Depends on behaviors of individuals!
• One of the most important is the predatorprey interaction.
• Reason predators are keystone species.
• The prey killed by predators is the “cost of
operation” of the ecosystem
• This is lethal effects
Non-lethal effects
• Beyond killing prey, predators have an
overwhelming non-lethal influence
• Landscape of fear again
• Predators “keep everyone in their place”!
• Cascading effects
Predation and Conservation
• The role of predatory behavior and
conservation of ecosystem processes
• Saw fear affects behavior and habitat use.
Elk
Level of vigilance of females with calves before and after
The reintroduction of wolves in Yellowstone.
70
Females with calves in area with wolves
60
% Vigilance
Females with calves in areas originally without wolves
50
40
30
20
10
0
1
2
3
4
Number of years after wolf reintroduction
5
6
3
Area with wolves
Y = 1.9 - 0.002 X
Area without wolves
a
2
Number of fecal groups/10m2
r = 0.66, P = 0.001
2
1
0
NS
0
100
200
300
400
Distance from forest edge
Elk: Habitat use patterns
500
600
Deer and Pumas.
GUDs for deer in
two types of forest.
1.5
1.4
1.3
1.2
1.1
Open areas
Forest edges
Forest areas
1.0
GUD (kg)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Douglas Fir
Mountain Mahogany
Habitat type
Fecal groups/10 m2
6
Open
Edge
Forest
Average # fecal groups/ 10 m2
5
4
3
2
1
0
Year 1 Year 2
Year 1 Year 2
Juniper
Fir
Deer: Habitat use.
Year 1 Year 2
Mahogany
Year 1 Year 2
Aspen
Produces landscapes of fear
• Where animals are afraid to go and if they do,
are less efficient in foraging.
October 2008 VAN DER MERWE AND BROWN—MAPPING THE LANDSCAPE
OF FEAR 1167
FIG. 3.—Open Colony study site. A)
Landscape of fear superimposed
on map of feeding stations and burrow
entrances. Contour
lines represent areas of similar
quitting harvest rates. Units are in
joules per minute. Differences
between contour lines indicate
differences
in predation cost of foraging. B)
Landscape of fear superimposed
on map of tree positions. The species
code in the key is: A.m.
for Acacia mellifera. Contour lines
represent areas of similar quitting
harvest rates. Units are in joules per
minute. Differences between
contour lines indicate differences in
predation cost of foraging.
Effect on vegetation?
• Herbivores are plant predators
• The less predation, the more survival, the
higher the population density
Ripple and Beschta. 2004. BioScience. 54: 755-766
What next?
• Cascading effects
• More plants, more production for other
species.
• Other species provide resources for still more.
• Etc. etc.
Best example
• Yellowstone National
Park
More?
• Coyote example:
• Mesopredators return.
What next?
• Enough!
• Still a lot more on how behavior effects
conservation efforts, it is the key!
The end
• Hope you have enjoyed the course
• Hope you learned something!
• At the very least, that behavior IS important
• Final: May 5; 2:45-4:45, 146 Baker