Population Management Minimum Viable Population The smallest population

Population Management

Minimum Viable Population • The smallest population for a species which can be expected to survive for a long time • Many factors effect MVP – the study of those factors is often called Population Viability Analysis – or Population Vulnerability Analysis – or PVA

English Skylark

Metapopulations

Metapopulation • A series of small, separate populations united together by dispersal • Thus even if all members of one population go extinct, other populations survive and dispersal from survivor populations can recolonize the area – a rescue effect

Metapopulation Dynamics

Bay Checkerspot Butterfly

Population dynamics of Bay Checkerspot Butterfly

Bay Checkerspot Jasper Ridge

Species persistence in metapopulations Varies with factors effecting extinction and colonization such as: • Distances between patches • Species dispersal ability • Number of patches

Types of Metapopulations

Possible mountain (desert bighorn) sheep dispersal routes Dispersal corridors predicted by the best-fitting dispersal model (15/0 10) and the HM population model, depicted with hill-shade topography. Black lines indicate least-costly corridor routes for corridors with, yellow lines indicate least-costly corridor routes that (a) were severed by anthropogenic barriers; or (b) were re-established by translocated populations. Corridors are presented based on (a) all extant populations within the study area, with and without current anthropogenic barriers considered; and (b) extant populations with and without those successfully reestablished by translocation, with current anthropogenic barriers considered. Epps et al. 2007

Furbish’s Lousewort

Population Management

Population Management We will discuss techniques we will need to use to save species after we have already learned its basic population structure and the factors effecting it We will concentrate on techniques for: • providing resources that may be scarce such as food or water • controlling threats such as predators, especially human predators • directly manipulating populations such as moving individuals to new sites

Providing Resources

Coal tit at bird feeder in the U. K.

Tufted Titmouse

Distribution of Tufted Titmouse

California Condor

California Condor distribution – Pre-Historic

California Condor in Southern California

American Burying Beetle

Feeding animals has two potential drawbacks: 1) it may foster long-term dependence on people, leaving animals vulnerable to starvation when feeding stops; 2) feeding concentrates animals and may make it easier for diseases to spread or for predators to find them

Cooper’s Hawk

Cooper’s Hawk at Bird Feeder

Black Bear at Bird Feeder

Chimps Eating

Small Whorled Pogonia

Adding water – Houbara Bustard

Houbara Bustard

Physical Environment Thornber’s Fishhook Cactus

Saguaro Cacti with Palo Verde Nurse Tree

Red-cockaded woodpecker

Red-cockaded woodpecker distribution

Red cockaded woodpecker nest

Artificial Reefs

Hedgerows in England

Hedge row complexity

Species Interactions – Black-footed Ferret

Black-tailed Prairie Dog

Eastern Fringed Prairie Orchid

Distribution of Eastern Fringed Prairie Orchid

Sphinx Moth

Hand Pollinating Fringed Prairie Orchid

Cooperative Breeding in Red. Cockaded Woodpeckers

Controlling threats to populations • Especially small-scale, local threats

Poaching – South Dakota

Yellow Lady-slipper Orchid

Letter to a Wild-flower Digger • “This letter is addressed, through the columns of the State Journal, to that unknown person who last week dug up the only remaining yellow ladyslipper in the Wingra Woods. While your name is unknown, your action sufficiently portrays the low estate of either your character or your education. On the chance that the latter rather than the former is at fault, I address to you this letter. I address it to all whose gardens at this season suddenly blossom forth with new wildflowers lifted from other people’s woods. ” – Aldo Leopold 1938

Types of Mortality Compensatory mortality occurs when human harvesting does not increase mortality above natural levels Additive mortality occurs when human harvesting does increase mortality above natural levels