so in conclusion, what can we say about abiotic factors, especially climate? (1)abiotic factors...

So in conclusion, what can we say about Abiotic factors, especially climate?

(1) Abiotic factors influence species’ distribution and abundance

But it also –

(2) Shapes organisms: morphology, physiology, and behavior

But, we can ask: “Are most organisms always found where their abiotic needs are met”?

Dispersal limited

We’d expect no ArboretumsWe’d expect no zoos We’d expect no Invasive spp

While abiotic factors represent a filter for what can exist at a given time and in a given space, BIOTIC factors play a pivotal role (another filter) on what does exist

Balanus and Chthamalus show zonation in tidal habitatsJoseph Connell 1961

Experimental- caged predators- removed competitors- transplanted rocks w/barnacles- monitored responses

Alwayssubmerged

Alwaysexposed

Conclusions of Connell’s study

(1) Organisms are limited by abiotic conditions that set ‘hard’ limitson their distribution (for barnacles it’s the upper tidal zone).

(2) Organisms are also limited in their distribution by the biotic components of their environment (competitors, predators) that may set ‘softer’ limits (esp. Chthamalus – competition).

(3) Removal of biotic factors can result in expansion in the distribution an organism – its geographic range, range of habitats where it occurs (Connell’s study), abiotic conditions in which its found, and so on…

‘hard’ = absolute ‘soft’ = dependent on the presence of another organism

Concept of the NICHE

Let’s synthesize the material so far in the

Let’s consider the concept of niche –If I knew what it meant I’d be rich.Its dimensions are n But a knowledge of ZenIs required to fathom the bitch

- Grant Cottam and David Parkhust

The environmental factors that influence the growth, survival, and reproduction of a species – Molles Textbook

Functional role of a species in the community, including activities and relationships – Smith and Smith Textbook

The environmental factors that influence the growth, survival, and reproduction of a species – Molles Textbook

Functional role of a species in the community, including activities and relationships – Smith and Smith Textbook

Species have requirements (water, temp, food, mates, etc…)

Species have impacts (they eat things, i.e., deplete resources, they build things, they destroy things, etc…)

Figure 22.9

min maxTemp

Abundance

A single Niche axis

Sp

ecie

s ab

un

dan

ce

min max min max

min maxm

inm

ax

Temp Water

Abundance

Two Niche axes

min max min max

min maxm

inm

ax

Temp Water

Abundance

Two Niche axes with interactions between variables

min max min maxTemp Water

min maxPH

TempPH

Water

Three Niche axes

min max min maxTemp Water

min maxPH

min maxCalcium

A multi-dimensional mess!!Hutchinson’s n-dimensional niche

min max min maxTemp Water

min maxPH

min maxCalcium

The niche can be visualized, conceptually, as an n-dimensional volume that defines all the conditions in which an organism can survive

The Fundamental Niche is the total niche volume determined solelyby Abiotic factors

The Realized Niche is a subset of the F. Niche that an organismactually occupies – the difference being the influence of Biotic factors:

e.g., predators, competitors, food

More definitions:

Fundamental Niche

Realized Niche R0 > 1.0

R0 < 1.0

The Niche concept place in a Population Framework

predation

competition

Factor One

Fac

tor

Tw

o

The environmental factors that influence the growth, survival, and reproduction of a species – Molles Textbook