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