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Africanized HoneybeesBIOL 3240 Plant and Animal Ecology – Population Dynamics

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Collared Doves

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Rapid Changes in Response to…BIOL 3240 Plant and Animal Ecology – Population Dynamics

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Dispersal in Rivers and Streams

• Stream dwellers have mechanisms to allow them to maintain their stream position.– – –

• Tend to get washed downstream in spates.– Muller hypothesized populations maintained via…

•

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Dispersal in Rivers and StreamsBIOL 3240 Plant and Animal Ecology – Population Dynamics

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Metapopulations

• A __________________ is made up of a group of subpopulations living on patches of habitat connected by an exchange of individuals.– Alpine Butterfly - Roland et al.– Lesser Kestrels - Serrano and Tella.

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Patterns of Survival

• Three main methods of estimation:– • Identify individuals born at same time and keep records

from birth.– • Record age at death of individuals.

– • Calculate difference in proportion of individuals in each

age class.• Assumes differences from mortality.

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High Survival Among the Young

• Murie collected Dall Sheep skulls, Ovis dalli.– Major Assumption: Proportion of skulls in each

age class represented typical proportion of individuals dying at that age.• Reasonable given sample size of 608.

– Constructed ____________________.• Discovered bi-modal mortality.

– <1 yr.– 9-13 yrs.

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Survivorship Curves

• __________: Majority of mortality occurs among older individuals. –

• __________: Constant rate of survival throughout lifetime.–

• __________: High mortality among young, followed by high survivorship.–

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Survivorship CurvesBIOL 3240 Plant and Animal Ecology – Population Dynamics

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Age Distribution

• Age distribution of a population reflects its history of survival, reproduction, and growth potential.

• Miller published data on age distribution of white oak (Quercus alba).– Determined relationship between age and trunk

diameter.– Age distribution biased towards young trees.• Sufficient reproduction for replacement.

– Stable population

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Age Distribution

BIOL 3240 Plant and Animal Ecology – Population Dynamics

What can you say about this population?

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Age Distribution

• Rio Grande Cottonwood populations (Populus deltoides wislizenii) are declining.– – Reproduction depends on …• •

– Because floods are absent, there are now fewer germination areas.

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Rates of Population Change

• ____________: Number of young born per female.

• _____________________: Tabulation of birth rates for females of different ages.

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BIOL 3240 Plant and Animal Ecology – Population Dynamics