Download presentation
Presentation is loading. Please wait.
1
Please switch to ‘slide show’ mode (press F5)
2
This is a presentation by Titles A model involving self-assembling modular plants Roderick Hunt, Ric Colasanti & Andrew Askew University of Sheffield It is all about SAM
3
Community image This is what a community of virtual plants looks like Contrasting tones show patches of resource depletion
4
CSR type, frame 1 This is a single propagule of a virtual plant It is about to grow in a resource-rich above- and below-ground environment
5
ditto f. 2
6
ditto f. 3
7
ditto f. 4
8
ditto f. 5
9
ditto f. 6
10
ditto f. 7
11
ditto f. 8
12
ditto f. 9
13
ditto f. 10
14
ditto f. 11
15
ditto f. 12
16
ditto f. 13
17
ditto f. 14
18
ditto f. 15
19
ditto f. 16
20
ditto f. 17
21
ditto f. 18
22
ditto f. 19
23
ditto f. 20 The plant has produced abundant growth above- and below-ground and zones of resource depletion have appeared
24
Binary tree diagram Above-ground binary tree base module Below-ground binary tree base module Above-ground array Below-ground array Above-ground binary tree ( = shoot system) Below-ground binary tree ( = root system) A branching module An end module Each plant is structured like this This is only a diagram, not a painting !
25
Water and nutrients from below-ground The branching (parent) modules can pass resources to any adjoining modules Explanation The end-modules capture resources: Light and carbon dioxide from above-ground In this way whole plants can grow
26
The virtual plants interact with their environment (and with their neighbours) just like real ones do They possess most of the properties of real individuals and populations Explanation For example …
27
S-shaped growth curves
28
Older plant, low nutrient Partitioning towards the resource-poorer half of the environment
29
Allometric coefficients Maintaining a functional equilibrium above-and below-ground
30
Older plant, asymmetric nutrients Foraging towards resources in a heterogeneous environment
31
Dense population And when many plants are grown together in a dense population …
32
Self-thinning … they exhibit self-thinning but as the plants are 2-dimensional the thinning slope is not –3/2
33
All of these plants have the same specification ( modular rulebase ) But this specification can easily be changed if we want the plants to behave differently… Explanation
34
For example, we can recreate J P Grime’s system of C-S-R plant functional types For this, the specifications we need to change are those controlling morphology, physiology and reproductive behaviour … Explanation
35
Modular rulebase
36
With three levels possible in each of three traits, 27 simple functional types could be constructed However, we model only 7 types ; the other 20 include Darwinian Demons that do not respect evolutionary tradeoffs Explanation
37
Let us see some competition between different types of plant Initially we will use only two types … Explanation
38
R-CSR-R, frame 1 Small size, rapid growth and fast reproduction Medium size, moderately fast in growth and reproduction
39
ditto f. 2
40
ditto f. 3
41
ditto f. 4
42
ditto f. 5
43
ditto f. 6
44
ditto f. 7
45
ditto f. 8
46
ditto f. 9 ( Red enters its 2 nd generation)
47
ditto f. 10
48
ditto f. 11
49
ditto f. 12
50
ditto f. 13
51
ditto f. 14
52
ditto f. 15
53
ditto f. 16
54
ditto f. 17
55
ditto f. 18
56
ditto f. 19
57
ditto f. 20 White has won !
58
Now let us see if white always wins This time, its competitor is rather different … Explanation
59
CSR-C-CSR, frame 1 Medium size, moderately fast in growth and reproduction Large size, very fast growing, slow reproduction
60
ditto f.2
61
ditto f.3
62
ditto f.4
63
ditto f.5
64
ditto f.6
65
ditto f.7
66
ditto f.8
67
ditto f.9
68
ditto f.10
69
ditto f.11
70
ditto f.12
71
ditto f.13
72
ditto f.14
73
ditto f.15
74
ditto f.16
75
ditto f.17
76
ditto f.18
77
ditto f.19
78
ditto f.20
79
ditto f.21
80
ditto f.22
81
ditto f.23
82
The huge blue type has out-competed both of the white plants, both above- and below-ground And the simulation has run out of space … Explanation
83
ditto f.23 again
84
So competition can be demonstrated realistically … … but most real communities involve more than two types of plant Explanation
85
We need seven functional types to cover the entire range of variation shown by herbaceous plant life To a first approximation, these seven types can simulate complex community processes very realistically Explanation
86
For example, an equal mixture of all seven types can be grown together … … in an environment which has high levels of resource, both above- and below-ground Explanation
87
7 types, high nutrient, f.1
88
ditto f.2
89
ditto f.3
90
ditto f.4
91
ditto f.5
92
ditto f.6
93
ditto f.7
94
ditto f.8
95
ditto f.9
96
ditto f.10
97
ditto f.11
98
ditto f.12
99
ditto f.13
100
ditto f.14
101
ditto f.15
102
ditto f.16
103
ditto f.17
104
ditto f.18
105
ditto f.19
106
ditto f.20
107
The blue type has eliminated almost everything except white and green types And the simulation has almost run out of space again … Explanation
108
ditto f.20 again
109
Now we grow the equal mixture of all seven types again … … but this time the environment has low levels of mineral nutrient resource, as indicated by the many grey cells Explanation
110
7 types, low nutrient, f.1
111
ditto f.2
112
ditto f.3
113
ditto f.4
114
ditto f.5
115
ditto f.6
116
ditto f.7
117
ditto f.8
118
ditto f.9
119
ditto f.10
120
ditto f.11
121
ditto f.12
122
ditto f.13 (a gap has appeared here)
123
ditto f.14
124
ditto f.15 ( red tries to colonize)
125
ditto f.16
126
ditto f.17
127
ditto f.18
128
ditto f.19
129
ditto f.20 (but is unsuccessful)
130
ditto f.21
131
ditto f.22
132
White, green and yellow finally predominate … … blue is nowhere to be seen … Explanation … and total biomass is much reduced
133
ditto f.22 again
134
Environmental gradients can be simulated by increasing resource levels in steps Explanation Whittaker-type niches then appear for contrasting plant types within these gradients
135
Whittaker-type gradient (types)
136
Next we grow the equal mixture of all seven types again … … but this time under an environmental gradient of increasing mineral nutrient resource Explanation
137
Stress-driven hump Greatest biodiversity is at intermediate stress
138
Now, environmental disturbance can be defined as ‘removal of biomass after it has been created’ Explanation For example, grazing, cutting, burning and trampling are all forms of disturbance
139
In our model, ‘trampling’ can be applied simply by removing shoot material from certain sizes of patch at certain intervals of time and in a certain number of places Explanation Other forms of disturbance can be simulated by varying each of these factors
140
So we grow the equal mixture of all seven types again … … but this time under an environmental gradient of increasing ‘trampling’ disturbance Explanation
141
Disturbance-driven hump Greatest biodiversity is at intermediate disturbance … … but the final number of types is low
142
Environmental stress and disturbance can, of course, be applied together Explanation This can be done in all forms and combinations
143
Again we grow the equal mixture of all seven types … … but with one of seven levels of stress and seven levels of disturbance in all factorial combinations Explanation
144
Productivity-driven hump Greatest biodiversity is at intermediate productivity
145
The biomass-driven humpbacked relationship is one of the highest-level properties that real plant communities possess Yet it emerges from the model solely because of the resource-capturing activity of modules in the self-assembling plants Explanation
146
Productivity-driven hump
147
(Dissolve to black)
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.