Community Ecology Ranging Behavior Intergroup Interactions Interspecies Interaction Predation Primates & Plants

Community Ecology

Ranging Behavior

Intergroup Interactions

Interspecies Interaction

Predation

Primates & Plants

Home Range

The entire range of a group of animals

The widest area in which a group of animals travel

A circumscribable area in which all daily and seasonal activities take place

Longer studies tend to have longer home range estimates for the species

Determining Home Range

1. Grid Count Method - Mark the position of the animals on a map, superimpose a grid, count the # of grids entered, calculate area

2. Minimum Convex Polygon - Mark the position of the animals on a map, draw a polygon around all the points, calculate the area of the polygon

3. Digitized Polygon

Legend

Trails

Clearings

Road

Study Area

Monkey River

All A points 0 175 350 525 70087.5Meters

0 180 360 540 72090

Meters

Legend

All A points

Trails

Clearings

Monkey River

Road

Study Area

Grid Cell Count

Legend

Trails

Clearings

Road

Study Area

Monkey River

A home range - DP 0 175 350 525 70087.5Meters

Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

Grid Cell 20 m X 20 m





0 180 360 540 72090Meters

Legend

All A points

Trails

Clearings

Monkey River

Road

Study Area

Legend

Trails

Clearings

Road

Study Area

Monkey River


Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

MCP





Digititzed Polygon

Tag and take a location reading of each tree in which the animals are seen (Long/Lat or UTM) using GPS

Import into GIS software (ex ArcGIS)Put a buffer around each point (or around the

day ranges) = to average group spreadJoin the points in a tight polygon – subtract

lacunae, have program calculate the area

Legend

Trails

Clearings

Road

Study Area

Monkey River


Legend

June 16

Aug 9

Sept 14

Trails

Clearings

Monkey River

Road

Study Area

Legend

Trails

Clearings

Road

Study Area

Monkey River


Legend

June 16

Aug 9

Sept 14

Trails

Clearings

Monkey River

Road

Study Area

June 16 day range

Legend

Trails

Clearings

Road

Study Area

Monkey River


Legend

June 16

Aug 9

Sept 14

Trails

Clearings

Monkey River

Road

Study Area

June 16 day range

Aug 9 day range

0 180 360 540 72090Meters

Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

All A ranges

0 180 360 540 72090Meters

Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

All A ranges

Buffer of day ranges

0 180 360 540 72090Meters

Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

All A ranges


MCP of day ranges

0 180 360 540 72090Meters

Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

All A ranges


MCP of day ranges

Lacunae to include (<1% of total area)0 180 360 540 72090

Meters

Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

All A ranges

Final DP

Legend

Trails

Clearings

Road

Study Area

Monkey River


Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

MCP

Minimum Convex Polygon• Easy to calculate• Comparable between sites• Overestimates area• Longer the study, the larger the area

Legend

Trails

Clearings

Road

Study Area

Monkey River


Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points


Grid Cell Count• Size of cell greatly influences area• Core use easily calculated

0 180 360 540 72090Meters

Legend

Trails

Clearings

Monkey River

Road

Study Area

All A points

All A ranges

Final DP

Digitized Polygon• Most accurate• Harder to calculate• Errors associated with GPS• Utilizes both point and line data

(sightings and day ranges)

Home Range

Related concepts/measures

• Core area – areas in which the group spends disproportionately large amounts of time – ex main feeding trees, sleeping trees, water holes. Areas integral to daily life.

• Daily Path Length or Day Journey Length – distance an animal or group travels in a day

Core Area

0 180 360 540 72090Meters

Legend

All A points

Trails

Clearings

Monkey River

Road

Study Area


Core Use Area

Home RangeMay or may not be defended, in

part or whole

The part that is actively defended and exclusively used we call a territory

Some animals are not territorial – they do not actively defend or exclusively use any area.

Territory

Area that is actively defended and exclusively used

Territoriality – the behavior (active defense and exclusive use) associated with the territory

Territoriality – expressed in at least 4 ways

1. Scent Marking - marmosets

2. Vocalizing - howlers

3. Display - gibbons

4. Physical Confrontation – chimpanzees

Functions of Territoriality?(agonistic between group interactions)

1. Defence of food supply (females)

2. Defence of females (males)

3. Protection against infanticide

4. Phylogeny

5. Link to monogamy?

Different explanations in different cases – probably not a single phenonmenon

Intergroup Interactions

Range from very friendly in some species to very aggressive in others

• Some regularly join up and form supertroops (ex hamadryas, geladas)

• Some are violently territorial – chimps?

• Some groups have extensive range overlap and just avoid each other

Intergroup Dominance

• When one group is able to consistently displace another group regardless of where they meet

• Between group competition

• Which group is dominant depends on group size, sometimes the number of adult males

Interspecies Interactions

Allopatry – when the geographic ranges of 2 species do not overlap. They are geographically separated from one another. Ex. Lemurs and lorises.

Sympatry – when two or more species have overlapping geographic ranges. Result is competition for resources. More closely related the species, the more intense the competition. Ex. Spiders, howlers, cebus

Competitive Exclusion

Complete competitors cannot coexist

Animals with similar needs, living in the same place, must find ways to reduce the direct competition

Niche divergenceAka – partitioning, differentiationWithin the same general area, there many be many

distinct habitats, and many distinct ecological niches.

Niche divergence allows similar species to reduce competition through separation of some or many aspects of their ecology.

Ex – slight differences in diet, forest strata, activity patterns

Two kinds of competition

1. Outright interference (contest) – usually involves aggression (chasing etc). Sympatric primates sometimes form interspecific dominance hierarchies (ex spiders & howlers in Costa Rica)

2. Exploitation (scramble) – trying to exploit a resource that others have already exploited/eaten. General reduction in available resources.

Effects of Interspecific Competition

The less successful competitor will generally experience a reduction in any/all of these:

• Population density

• Geographic distribution

• Ranging patterns

• Dietary diversity

Benefits of Interspecies Interactions

• Access to otherwise inaccessible food sources

• Increased predator detection and warning

• Improved competitive ability

• Social benefits?

Predation

Assumed to be a major force in primate behavior and social life

Actual data on predation risk or threat is

Actual reports of predation on primates are rare

Reports of predation on primates are rare because

• Predators avoid humans – predation does not take place when we are there

• Many predators hunt at night

• We are normally studying the prey, not the predators (chimp/colobus exception)

• Maybe predation is actually rare? Not likely.

Indirect Evidence

The existence of regular, predictable predator defence behaviors & other adaptations

• many small primates are cryptic

• many are vigilant

• all have alarm calls

These things only make sense if we assume that there is predation pressure

Predation and Infanticide

Similar pattern – Theoretically – both are credited with being a major force in the evolution or primate social life.Empirically – both are relatively rare behaviors and thus we have relatively little good solid quantitative data Actual evidence - both rely on the existence of counterstrategies (anti-predator and anti-infanticide)

Primates as Prey

Predators that prey on primates:

• Carnivores (big cats, wild dogs)

• Crocodiles at waterholes

• Raptors (hawks, eagles)

• Snakes

• Other primates

Primates as Predators

1. Humans - everything

2. Chimpanzees – galagos, bushbabies, blue monkeys, red tail monkeys, baboons, black and white colobus, red colobus (35 types of vertebrate animals)

3. Baboons - small deer & vervet monkeys

4. Blue monkeys – galagos & bushbabies

Primates and PlantsDo primates help or hinder plants?

Hinder – flower and seed predators, damage to limbs and bark

Help – pollination & seed dispersal

Primate – Angiosperm Coevolution?

Documents

Community Ecology Ranging Behavior Intergroup Interactions Interspecies Interaction Predation Primates & Plants