1. Ecological succession
Patterns in time
Ecological succession
Frederic E. Clements
Henry A. Gleason
Plant succession is the historically influenced random process leading to different stable states despite identical environmental conditions (Gleason 1927)
Plant succession is the directional development of the vegetation of a given homogeneous area over a period of time towards a single climax structure (Clements 1916)

2. The Human impact on the biosphere

3. Primary Successional stages
Bare soil of rocks
Succession is not a deterministic process.
The successional sequence might end in different final stable states
Annual and biannual plants
Soils crusts, Cyanobacteria, Lichen, Mosses
Pioneer species
Shrubs, trees
In many temperature successioal series forests form the climax community
Climax community

4. Succesion of freshwater bodies

5. Soil crusts stabilize soils and increase water retention.
Cyanobacteria, mosses, lichen
Soil mosses and lichen
Crusts are well adapted to severe growing conditions, drought and water loss.
Crusts generally cover all soil spaces not occupied by vascular plants, and may be 70% or more of the living cover
Cyanobacteria
Soil crusts stabilize soils and increase water retention.

6. Major disturbances are Fire Storm Flooding Lava flows
Secondary succession
Secondary succession is the change in faunal or floral composition after severe disturbance
Major disturbances are
Fire
Storm
Flooding
Lava flows
Secondary succession starts mainly from seed banks.
Colonization is often of minor importance.
Seeds remain healthy for some months to more than 1000 years.
In cyclic succession (frequent fires) seed banks allow for fast recover.

7. Adaptive strategies Young field Midfield Woodlands Successional stage
Modified from Brown, Southwood 1987
Adaptive strategies
Plants, herbivorous insects
Generation time
Reproductive effort
Plants, aphids
Plants, birds, some insects
Niche breadth
Morphological diversity
Herbivorous insects
Flight ability
Bees, wasps
Diversity
Plants, insects
Young field
Midfield
Woodlands
Successional stage
Different successional stages filter for different life history strategies (habitat filtering)

8. Habitat templates (Southwood and Greenslade)
The r – K – A triangle
Habitat templates (Southwood and Greenslade)
The habitat template of Southwood and Greenslade is a classical form to characterise species along a gradient of adaptational strategies but also to classify habitats. Modified from Brown and Southwood (1987) [Brown V. K., Southwood T. R. E – Secondary succession: patterns and strategies (In: Colonization, Succession and Stability, Eds. A. J. Gray, M. J. Crawley, P. J. Edwards) – Blackwell, London, ].

9. Community patterns during succession
Annuals and biannuals
Annuals and biannuals
Abundance
Shrubs
Species richness
Shrubs
Trees
Trees
Time
Time
Species richness, total abundance, and total biomass generally peak at intermediate stages of succession.
Biomass
Time

10. Succession of beta diversity
Alpha Diversity of green plants peaks at intermediate successional stages. b diversity, the structural diversity on the other hand, rises. Macrofungi do not follow this pattern, there a diversity continuously rises during succession. Redrawn from Brown and Southwood (1987) [Brown V. K., Southwood T. R. E – Secondary succession: patterns and strategies (In: Colonization, Succession and Stability, Eds. A. J. Gray, M. J. Crawley, P. J. Edwards) – Blackwell, London, ].
Brown, Southwood 1987

11. Intermediate disturbance
Competitiion
New Zealand stream invertebrates (Townsend 1997)
Extinction
Immigration
Number of niches

12. P. ob-longo-punc-tatus
The Markov chain approach to succession
Henry S. Horn 1941-
Species
P. melanarius
P. ob-longo-punc-tatus
P. niger
O. ob-scurus
H. 4-punc-tatus
C. granu-latus D0 D1 D2
EV1
Pterostichus melanarius
0.049
0.336
0.280
0.315
0.166
0.098
12.00
4.63
4.98
0.940
Pterostichus oblongopunctatus
0.093
0.068
0.052
0.016
0.268
5.00
2.23
3.74
0.700
Pterostichus niger
0.105
0.186
0.158
0.001
0.207
0.072
3.00
2.95
2.92
0.597
Oxypselaphus obscurus
0.272
0.107
0.261
0.034
0.087
4.00
5.53
4.12
0.751
Harpalus 4-punctatus
0.288
0.277
0.031
0.091
0.232
0.238
1.00
5.77
5.05
1.000
Carabus granulatus
0.192
0.026
0.292
0.316
0.092
0.226
4.89
5.19
0.908
Sum
Abundances
Column stochastic transition probability matrix
𝑁 𝑡+1 =𝑃 𝑁 𝑡
Stable state (eigen)vector

13. Positive interactions
Bertness, Leonhard, Ecology 78:
Positive interactions
Joint defences
Habitat amelioration
Frequency of competitive interactions
Frequency of positive interaction
Increasing physical stress
Increasing consumer pressure
The model of Bertless and Callaway (1994) predicts conditions under which positive interactions are expected to be important forces in community structure. Positive interactions are assumed to be important under harsh physical conditions or high consumer pressure. Redrawn from Bertness and Leonard (1997.[Bertness M. D., Callaway R Positive interactions in communities: a post cold war perspective - Trends Ecol. Evol. 9: ; Bertness M. D., Leonhard G. H The role of positive interactions in communities: lessons from intertidal habitats - Ecology 78: ]
The stress gradient hypothesis predicts increased proportions of positive (mutualistic) interactions in plant communities at intermediate levels of stress and herbivore pressure.

14. Linked patterns in time
Population dynamics (1964 to 1983) of the red squirrel in 11 provinces of Finland (Ranta et al. 1997) -3 -2 -1 1 2 3
1964
1968
1972
1976
1980
Oulu
Vaasa
Häme
Turku-Pori
Central Finland
Uusimaa
Lapland
Kuopio
North Karelia
Mikkeli
Kymi
Patrick A.P. Moran ( )
The Moran effect
Regional sychronization of local abundances due to correlated environmental effects

15. Defoliation by gypsy moths in New England states
100000
200000
300000
400000
500000
600000
700000
Acres Defoliated
Maine
500000
Acres Defoliated
New Hampshire
20000
40000
60000
80000
100000
120000
140000
Acres Defoliated
Vermont
Lymantria dispar
500000
Acres Defoliated
Massachusetts
Year 20 30 40 50 60 70 80 90
Gradation:
The massive increase in density
Data from Williams and Liebhold (1995)

16. Taylor’s power law
Assume an assemblage of species, which have different mean abundances and fluctuate at random but proportional to their abundance.
Going Excel
The relationship between variance and mean follows a power function of the form
Taylor’s power law; proportional rescaling

17. Ecological implications
Temporal variability is a random walk in time
Abundances are not regulated
Extinctions are frequent
Temporal species turnover is high
Temporal variability is intermediate
Abundances are or are not regulated
Extinctions are less frequent
Temporal species turnover is low
Temporal variability is low
Abundances are often regulated
Extinctions are rare
Temporal species turnover is very low

18. Evolutionary time scales
Niche conservatism refers to the tendency of closely related species to have similar niche requirements. The requirements translate into similar ecological, morphological or behavioural traits mediated by genomic similarities.
100%
Body size
Female body length
Sex dimorphism
How much variance in important niche dimensions of European plants is explained by taxonomc relatedness?
Male body length
Dietary range
Colours
Migratory behaviour
50%
Shading preference
Abundance
Moisture preference
German range size
Shading tolerance
Moisture tolerance
Habitat tolerance
European range size 0%
Spiders
Birds
Entling et al. 2007, Gl. Ecol. Biogeogr. 16:
Prinzing et al Proc. R. Soc. B 268: 1.

19. Taxon species richness and local abundances The case of Hymenoptera
Continental taxon species richness of Hymenoptera is correlated to mean local abundances
Species rich hymenopteran taxa contain more locally rare and fewer locally abundant species 1 2 3 4 5 10
100
1000
10000
Number of species
Mean density
per species
0.2
0.4
0.6
0.8 1 10
100
1000
10000
Number of species
Fraction of
singletons
Ulrich W. 2005c. Regional species richness of families and the distribution of abundance and rarity in a local community of forest Hymenoptera. Acta Oecol. 28:
0.2
0.4
0.6
0.8 1 10
100
1000
10000
Number of species
Fraction of
abundant species

20. Species richer sites contain relatively less higher taxa.
Numbers of families and species scale allometrically to floral species richness
y = 1.78x
0.77 R 2
= 0.94 10 20 30 40 50 60 80
Number of species in a flora
Number of genera
Species richer sites contain relatively less higher taxa.
Species richer sites have higher species per genus (S/G) ratios
Species richer sites contain higher proportions of ecologically similar species (environmental filtering)
y = 1.9x
0.61 R 2
= 0.70 5 10 15 20 25 30 35 40 60 80
Number of species in a flora
Number of families
Darwin’s competition hypothesis:
Closely related species should be ecologically more similar and under higher selection pressure than more distantly related species
An example how to study the relation between evolutionary history and phylogeny is the work of Enquist et al. (2002) about allometric scaling of higher taxer of woody plants on local species number. Larger sites (4 to 45 myr ago) contained significantly less higher taxa than expected by chance. (Figures modified from Enquist B. J., Haskell J. P., Tiffney B. H. (2002) General patterns of taxonomic and biomass partitioning in extant and fossil plant communities. Nature 419:
Enquist et al Nature 419:

21. Local community structure
Early succession
Regional pool of species
Regional pool of species
Regional pool of potential colonizers
Environmental filters
Facilitation
Random colonization
Phylogenetic clumping
Phylogenetic segregation
No phylogenetic structure
No phylogenetic structure
Local colonizers
Later succession
Positive interactions
Competition
Neutral interactions
Phylogenetic segregation
Phylogenetic clumping
No phylogenetic structure
Local community structure
Zaplata et al. 2013