Ecology

The scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance

Begon, Harper, Townsend, 2006, Ecology, Blackwell

Lecture outline

1. The evolution of life and life histories2. The flux of energy and matter3. Individuals and populations4. Ecological communities5. Positive and negative species interactions6. Trophic networks7. Distributions in time8. Distributions in space9. Function and diversity10. The human impact

Ecology is the scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance

Literature

Literature

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Ecological slideshows

Ecological e-books

The scientific study of the distribution and abundance of organisms and the interactions that determine

distribution and abundance

Distribution and abundance might relate to genes, individuals, populations, or species

The manifold of genes or species is called diversity.

Applied to all living beings we speak of biodiversity

Alfred Russel Wallace (1823-1913)

Charles Robert Darwin (1809-1882)

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K O S D C P T J Kr Pa N

Mass extinctions

E

Number of marine families

Species home range

Time

Allopatric speciation is generally slow

Peripatric speciation might be fast

Allopatric , peripatric, and sympatric speciation

Spatial breeding barrier

Allopatric and peripatric speciation: New species emerge by genetic divergence in geographically isolated regions

Sympatric speciation: New species emerge within the same habitat by any other breeding barrier. The include behavioural, resource use, or morphological barriers.

Tinamou

Ostrich

RheaSpotted Kiwi

North Island KiwiSouth Island Kiwi

Great Kiwi

Time80 0

Cassowary

Emu

Tinamou

The diversification of species

Australia

New Zealand

South Amercia / Africa

Low diversity of nine speciesComparably high genetic diversity

Today’s biodiversity is largely caused by evolutionary history and plate tectonics

Rhea

Cassowary

Zosterops abyssinicus

Zosterops poliogaster

Postglacial colonization of Europe

Hewitt G.M. 1999. Postglacial recolonisation of European biota. Biol. J. Linn. Soc. 68: 87-112.

During the last 10,000 years Central and Northern Europe was recolonised from multiple glacvial refuges where species survived the ice age.

The refuges are centres of gentic diversification.

Major refuges where: The MaghrebSpainTurkeySicilyCyrpusCrete

We reconstruct colonisation routs by the analysis of genetic diversity across Europe.

Because colonising populations are often small they are generically impoverished (founder effect).

Colonisation gradient

Founder effectsOrdered genetic loss

Relict populationsVicariant (scattered) genetic loss

Colonisation gradient

Carabus auronitens

Postglacial colonization of Europe

The allele - sites matrix is sorted according to allele richness

Popu-lations

Postglacial colonisation of European Tenebrionidae (Coleoptera)

Three major postglacial refuges with high numbers of endemics and high rates of glacial speciation

Three major colonisation routes

Reconstruction of postglacial colonisation using phylogenetic relatedness of species

Suboptimum

Ecological niches

Optimum

Water

Ligh

t Two niche dimensions of a plant

A given habitat filters species according to the abiotic conditions

Condition

Perf

orm

ance

Performance of a species

Repro-duction

Growth

Survival

G Evelyn Hutchinson, 1903-1991

The niche is the role a species plays in a community, rather than a habitat.

The niche is the sum of the habitat requirements that allow a

species to persist and produce offspring.

The niche is an n-dimensional hypervolume, where the

dimensions are environmental conditions and the resources that

define the requirements of an individual or a species to practise

Charles Elton, 1900-1991 Joseph Grinnell, 1877-1939

Profession

Place

Condition

Perf

orm

ance

Ecological niches emerge from differences in performance along the gradient of habitat conditions

Generalist speciesSpecialist

species

Formally a niche is the place of a species within a multidimensional hypervolume spanned by all resources used by this species.

Generalist species have relatively broad niches in comparison to specialist species.

A habitat is the place where a species occurs. Do not mismatch habitat and niche!

Condition

Perf

orm

ance

Fundamental nicheRealized

niche

Number of resources

Trop

hic p

ositi

on

Ground beetles (Carabidae) on Mazurian lake islands

Error bars denote a standard errorbasal

top

The carbon isotope ratio of body tissues (13C ⁄ 12C = δ13C) depends on resource width, while the nitrogen isotope ratio (15N ⁄ 14N = δ15N) increases in insects with trophic level.

Parts of the species are well segregated in trophic niche space, while another part of species highly overlaps in resource use.

The plot shows also three different guilds of species with similar resourse use.

Zalewski et al. 2013, Ann.Zool.Fenn

Trophic niche spaces in eukaryotes

Mineralisers

Producers

Green plants

Animals

Fungi, slime moulds, animals

Fungivores

Herbivores

Omnivores

Parasites

Omnivores are animals that feed on

other animals and plants

The specific trophic needs of organisms define their trophic niche.

Trophic niches are generally not species specific. They are highly variable in time and space. Consumers

Saprovores

Carnivores

Reducers

Latin GreekHerbivore PhytophageCarnivore ZoophageFungivore MycetophageOmnivore PantophageSaprovore SaprophageMicrovore MicrophageBacteriovore Bacteriophage