Understanding Ecological Niches: The Role and Place of Organisms in Ecosystems, Lecture notes of Ecosystem Modelling

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The Biological Niche

Role and Place in the

Ecosystem

With Cynthia Sanchez

Objectives

• To understand what a niche is in the field of

ecology

• To understand the differences between a

fundamental niche and a realized niche

• Why are niches important to understand
• How this knowledge is used

Niche

• Organisms carve out their own unique niches that they specialize in, and it is extremely unusual to find two organisms with the same exact niche. Too much competition for resources.
• https://study.com/academy/lesson/ecological-niche- definition-lesson-quiz.html
• Biotic factors – living things
• Abiotic factors – non-living

What is a NICHE?

Niche (figuratively) – to have found a position or occupation in society that is uniquely their own.

What Does a Hypervolume

Look Like?

• Fig. a three-dimensional _niche.

1. Specific Leaf Area (SLA) vs
2. Height of habitat
3. Seed Mass_

https://bblonder.wordpress.com/2014/02/26/the- ecological-niche-and-the-n-dimensional-hypervolume/

The Functional Hypervolume of Tree Species

Temperate Biomes

Tropical biomes

Overlapping Biomes

The Lichen – An Example of a

Biological Niche

• A lichen is a composite organism that arises from algae or cyanobacteria (or both) living among filaments of a fungus in a symbiotic relationship.[1][2][3]^ The combined life form has properties that are very different from the properties of its component organisms. Lichens come in many colors, sizes, and forms.

The Lichen – An Example of a

Biological Niche

• A macrolichen is a lichen that is either bush-like or leafy; all other lichens are termed microlichens .[1]^ Here, "macro" and "micro" do not refer to size, but to the growth form.[1]^ Common names for lichens may contain the word "moss" (e.g., "Reindeer moss", "Iceland moss"), and lichens may superficially look like and grow with mosses, but lichens are not related to mosses or any plant.[3]:

The Lichen – An Example of a

Biological Niche

• Lichens do not have roots that absorb water and nutrients as plants do[6]:2^ but like plants they produce their own food by photosynthesis using sunlight energy, from carbon dioxide, water and minerals in their environment.[7]^ When they grow on plants, they do not live as parasites and only use the plants as a substrate.

The

Fundamental

Niche

• The fundamental niche is usually NOT observed in nature. In a ‘perfect’ world (perfect for that particular species) this is what the niche for that species would potentially be.
• It sort of like FALSE ADVERTISING.

The FUNDAMENTAL Niche

Sunlight

Moisture

Orange lichen

The orange lichen likes a lot of sunlight, but does not like a lot of moisture.

Fundamental

Niche:

The conditions in which the species CAN survive (in theory)

The REALIZED Niche

The orange lichen likes a lot of sunlight, but does not like a lot of moisture.

Green Lican likes a lot of moisture, but does not like a lot

of sunlight.^ Sunlight

Moisture

Orange lichen Green lichen

Realized Niche:

The conditions in which the species ACTUALLY lives taking into acct competition (in reality)

Fundamental vs. Realized

Sunlight

Moisture

Sunlight

Moisture

The Realized Niche < Fundamental Niche Due to predation and competition

Due to abiotic factors Temperature, Moisture, Food, Shelter, Soil Composition, Sunlight

Due to biotic factors Predation, Competition

Gause's Law of Competitive

Exclusion

Sunlight

Moisture

Orange lichen Green lichen

• two species competing for the same resource cannot coexist at constant population values, if other ecological factors remain constant.

Organisms Must Compromise