Raymond L. Lindeman (1915- 1942) Energy and nutrient cycles Lindeman’s theory of energetic ecologic was th main trigger to initiate the international biological program (IBP) that run from 1964 to 1974 (European projects ended in the 80s). Heinz Ellenberg (1913-1997) Marine NPP Terrestrial NPP Tropical and subtropical oceans 13 Tropical rainforests 17. 8 Temperate oceans 16. 3 Broadleaf deciduous forests 1.5 Polar oceans 6.4 Boreal evergreen forests 3.1 Coastal shelfs 10. 7 Mixed forsts 3.1 Coral reefs 1.2 Savannahs 18. 8 Grasslands 2.4 Shrub steppes 1 Tundras 0.8 Deserts 0.5 Plantations 8 Total 48. 3 Total 56. 4 Some definitions: Biomass is the mass of organisms per unit of area. It is the standing crop. Units: J×m -2 or kg×m -2 The primary productivity is the amount of energy produced per unit area by plants. Net primary productivity is the difference between gross primary productivity (GPP) and autothrophic plant respiration (AR). Gross primary productivity (GPP )is the total fixation of energy by photosynthesis per unit of area. NPP=GPP-AR; Units: J×m ×year or kg C×m -2 ×year Net primary productivity (unit= 10 15 kg×year -1 ) Modified from Geider et al. 2001, Gl Change Biol, 7 Biome GPP Tropical rainforests 3-3.5 Broadleaf deciduous forests 1.1- 1.5 Boreal evergreen 0.7- Variability in gross primary productivity (unit= 10 12 kg C×year -1 ) Modified from Falge et al. 2002, Agr Forest
Energy and nutrient cycles. Lindeman’s theory of energetic ecologic was th main trigger to initiate the international biological program (IBP) that run from 1964 to 1974 (European projects ended in the 80s). . Heinz Ellenberg (1913-1997). Raymond L. Lindeman (1915-1942). Some definitions: - PowerPoint PPT Presentation
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Raymond L. Lindeman (1915-1942)
Energy and nutrient cyclesLindeman’s theory of energetic ecologic was th
main trigger to initiate the international biological program (IBP) that run from 1964 to 1974
(European projects ended in the 80s). Heinz Ellenberg (1913-1997)
Some definitions:Biomass is the mass of organisms per unit of area. It is the standing crop.Units: J×m-2 or kg×m-2
The primary productivity is the amount of energy produced per unit area by plants.Net primary productivity is the difference between gross primary productivity (GPP) and autothrophic plant respiration (AR). Gross primary productivity (GPP )is the total fixation of energy by photosynthesis per unit of area.NPP=GPP-AR; Units: J×m-2×year-1 or kg C×m-2×year-1Net primary productivity (unit= 1015 kg×year-1)
Habitats that are not ecosystems in a strict sens:
Rivers Oceans Agricultures
A community is a group of species that potentially interactAn assembly is any association of species within a given area
There is still a dispute whether ‚ecosystems’ are ‚systems’ in a strict sense.
Ecosystems are characterized by a flux of energy and a circulation of inorganic matter.
Herbivores
Carnivores
Parasites
Saprovores
Mineralisers
Consumers
Reducers
Plants
Algae
Producers
Dead organic matter
Microvores
Consumers
Herbivores
Minerals
O2, CO2, H20 Light O2, CO2, H20
Mineral sink
A simple scheme of an ecosystem
Regulated or not regulated?
𝑑𝐷𝑑𝑡 =𝑐𝐾−𝑎𝑃 𝑑𝐾
𝑑𝑡 =𝑏𝑃𝐾 −𝑐𝐾 𝑑𝑃𝑑𝑡 =𝑎𝑃−𝑏𝑃𝐾 𝑑𝐷
𝑑𝑡 +𝑑𝑃𝑑𝑡 +
𝑑𝐾𝑑𝑡 =𝑐𝑜𝑛𝑠𝑡
Modelling ecosystem processes
D, P, and K are the amounts of a resource at the levels of reducers (D), producers (P) and consumers (K), respectively. Then it holds
The flux of matter through the ecosystem is predicted
to be a steady state process
Simple ecological models predict ecosystems to be self-regulated entities.
Two types of regulation
Self controlled systemStatistical averaging
Control loop
Early ecological theory saw ecosystems as self regulated entities.Examples: Predator – prey relationshipsDegree of herbivoryEnergy fluxPopulation densitiesProductivityBiodiversity
The variance – mean relationship of most populations follows Taylors power law
The majority of species has 1.5 < z < 2.5
Z = <<2 is required for population regulation
Most populations, in particular invertebrate populations are not regulated!
They are not in equilibrium
𝜎 2(𝑁 )∝𝑁 𝑧
Statistical averaging as a stabilizing force
The Portfolio effect
The average of many random variables has a lower variance than each single variable: statistical averaging
Number of variables
Varia
nce Stability𝝈𝟐∝ 𝟏
√𝑵
Aggregate ecological variables (biomass, species richness, productivity, populations) become more stable with increasing number of independent variables.
For instance, total biomass and ecosystem productivity are more stable in species rich communities.
The soil system as an example of an ecological system
From Begon, Townsend, Harper, 006. Ecology, Blackwell
Earthworms
Microfauna
Darwin on earthworms
The soil system
Soil organisms: Edaphon
Domain Kingdom Phylum Class/Order Examples Ecological function
Prokaryote Bacteria Proteobacteria Nitrosomonas, Nitrobacter, Rhizobium, Azotobacter N cycle
Prokaryote Bacteria Firmicutes Clostridium N cycle
Eukaryote Chromalveolata Diatomea Primary producersEukaryote Chromalveolata Xanthophyceae Primary producersEukaryote Chromalveolata Ciliophora MicrovoreEukaryote Amoebozoa Amoeba MicrovoreEukaryote Plantae Chlorophyta Primary producersEukaryote Animalia Nematoda BacteriovoresEukaryote Animalia Rotifer SaprovoresEukaryote Animalia Tardigrada BacteriovoresEukaryote Animalia Arthropoda Collembola Fungivores
Eukaryote Animalia Arthropoda Arachnida Acarina Saprovores, Carnivores
Eukaryote Animalia Arthropoda Arachnida Pseudoscorpionida CarnivoresEukaryote Animalia Arthropoda Insecta Coleoptera CarnivoresEukaryote Animalia Arthropoda Insecta Diptera SaprovoresEukaryote Animalia Arthropoda Insecta Hymenoptera CarnivoresEukaryote Animalia Arthropoda Chilopoda CarnivoresEukaryote Animalia Arthropoda Diplopoda Carnivores
Eukaryote Animalia Annelida Clitellata Enchytraeidae, Lumbricidae Saprovores
Eukaryote Animalia Mollusca Gasteropoda Herbivores
The animals of each compartment in a German beech forest
Guild Group Main taxa No. of species Individuals x m-2 Biomass (mgDW x m-2)