Modelling Concepts Flashcards
Ift. research for bentiske arter. Der har været innovation of the predictive modelling methodology of changes. Changes for hvad ift de bentiske arter?
Organism abundance, biomass, biodiversity, productivity/food webs, habitat provision
Ift. bentiske arter. -to facilitate predictive scenario modelling of “what will happen if” in future management - hvad for populations forhold kigger man så på?
Identification of casual relationships between community changes and driving forces (natural environmental, anthropogenic) to be able to predict
Nævn eksempler på benthic suspension feeders. Og hvad er det man gør - når man suspension feeder/exreater
Mussels, Clams, cockles, oysters, ascidians, worms, marine sponges
–Suspension-feeding
* Particle capture
* Water processing
–Nutrient release
* Excretion
* Faeces and pseudofaeces production
What do we need models for?
Desciption is a first step towards understanding a system and ecology.
Se systemer og trends: Man kan se dynamikker og relationships mellem prey og predator fx
Simple models can be helpful: Easy to run and experiment with them. Can help explain counter-intuitive observations. Can make different scenarios (billigere end at gå ud in the field og lave experiments).
Deling af modeller: Det er ikke alle der vil dele deres modeller.
Tid til at køre modeller: Det kan åbenbart tage flere uger, at køre nogle af de komplicerede modeller.
Kan man modellere life cycles dynamics?
ja Life cycle dynamics: Kan også modelleres.
Forklar om tun modellen
Tun model: Det er en af de mest udarbejdede fish-models der findes. Om tuns migration.
Der er fx en trait-based tun model hvor man har trait-based alle byttedyrene som tun spiser. På den måde kan man forudsige bl.a. byttedyrenes abundance hvis der kommer mere tun predation
Forklar om population dynamics model
Simulate changes in biomass or number of individuals
Most food-web models and biogeochemical models falls here
Hvis en fisk er føde for mange andre fisk - kan man så modellere systemet? Kan man modellere hvad der vil ske, hvis man begynder at fiske mere på dem?
Mesopelagiske fisk - er bytte for mange andre fisk. Så hvis man begynder at fiske mere på dem, så kan man modellere hvordan det vil påvirke de andre fisk i økosystemet.
Forklar Individual-based models
Tend to follow one single individual (or many simultaneously) -> super individual
Often demanding to run
Might need and optimization if they simulate decision making (fx migration)
Forklar Food web models
Food web models are network models that represent prey/predator interactions to quantify the pathways of energy between the different ecological groups of an ecosystem
Different levels of complexity.
Mange arter og deres interactions.
Forklar Species based vs. Trait-based models
Species based - great for parametrization of single species, but uncertancy increase if you have to simulate all species. Often used in management.
Trait-based: How to describe the interaction between the many species.
Describes ecosystems as consisting of individuals rather than species and characterizes individuals by few key traits that are interrelated through trade-offs. (Size, resource acquisition mode, feeding strategy).
- focus on induviduals instead of species
- individuals characterized by few taxadecending key traits
- trade-offs associated with key traits
- trait distribution in nature depends directly on trade-offs
- in trait-based approach you need to quantify key-traits and trade-offs
It offers an alternative to classical species-centric approaches and has the potential to describe complex ecosystems in simple ways and to assess the effects of environmental change on ecosystem structure and function.
Forklar om modeller hvor man ikke har inkorporeret spatial dimensions.
We can run the model without any spatial dimension (0D models)
- We assume an environment forcing (fx nutrients and mean light in the mixed layer)
Forklar om modeller hvor spatial dimensions er implementeret? 1D og 3D. Hvad er trade-off med højere resolutions?
We can add a spatial dimension
- Water-column models (1D)
- 3D models (physical model or transport matrix) (Man behøver ikke vide alt om et økosystem, man kan bare koble til modeller der er bygget af et økosystem)
Global models are often ca. 1 degree resolution (111 km) og det er ikke så god resolution. Man prøver at lave dem bedre. Trade off between scale and resolution.
Forklar om earth system models. hvad er det, og hvilke dele er modelleret?
Earth system models
En kombination af forskellige modeller. Komplicerede.
Atmosfære. Land. Ocean. Vegetation. Chemistry. Atmosphere. Fysik. Biochemisty.
Hvordan vælger man en model? og hvad er tradeoffs når man bygger økosystemer?
Many models that do similar things
Hvordan vælger man?
Man finder ud af hvad man skal undersøge.
Hvem vil lave en model?
Flere modeller - man kan tjekke hvor godt en model passer på ens issue på en eller anden måde.
Bygge økosystemer kan være tricky. Der er trade-offs mellem om modellen er kompleks, hvor hurtigt den kører osv.