PP 1: Frameworks of Terrestrial Ecology: Site and Physiography

Major theme for the class

understanding whole ecosystems

what is bio-ecology

ecosystems are centered on organisms, added to a non-specific abiotic environment

what is geo-ecology

ecosystems are centered on geographic spaces, with a focus on the 3-dimensional units in which organisms dwell

Basic site framework

Basic site framework: abiotic factors

• things that make up the physical environment

• site = sum total of all physical factors of a specific place

Basic site framework: biotic factors

• the organisms themselves

Basic site framework: ecosystem

• site and biota bonded together, interacting and affecting each other

• they are convenient to separate, but are inseparable in reality

We define site along a moisture gradient

• defined by moisture because that’s where the nutrients are

• as water goes so does nutrients, so water is a key limiting factor

Physiography: the key to everything

• physiography is the physical geography of an area (typically geomorphology or topography)

• we are most interested in ecological geomorphology- studying surface features and their form and substance

• physiography= form (shape of the land) + substance (parent material)

Characteristics of physiography include:

• physiographic setting

• specific landform

• parent material of the landform

• position of the landform in the landscape

• position of the landform relative to others

Physiography indirectly affects or controls:

• macro- and microclimate

• moisture flux

• water table position

• nutrient status

Physiography also directly or indirectly controls:

• the likelihood of disturbance

• species occurrence and composition

• growth and biomass accumulation

• how ecosystems change (succession)

• variation within and among species

Physiographic systems of our glaciated terrain:

• Outwash plains

• Ice contact terrain

• moraines

• lake plains

outwash plains info

• water laid

• both dry and wet

• stratified drift

Ice contact terrain

• water laid

• includes kames, kettles, and eskers

• semi-stratified drift

Moraines information

• ice laid

• includes end, ground, and interlobate moraines; unstratified drift

lake plains information

• lacustrine

• sand or clay

• stratified drift

Physiography affects moisture availability in uplands:

• water table position

• capillary fringe

• perched water table

• soil texture and structure

• soil organic matter

• aspect

• slope position

• slope percent

• spatial relationship to other features

physiography patterns wetlands across a landscape:

• poorly- and very-poorly drained soils

• aeration (moving vs standing water)

• nutrients affected by parent material and water movement

• landscape position affects microclimate