Plant Community Subsystem
The Plant Community Subsystem interface generates data for the plant
growth simulation. There are a number of ways to use the plant growth
simulation, from modeling an aggregate community to species by species
growth modeling.
- Aggregate Community Model
- An aggregate community model would be expressed as the entire
plant community functional group growing at 100% of maximum
expression. This would be appropriate if the entire site
had similar values for the functional group characteristics
of each species, e.g. if there were 5 or 6 different warm
season grasses on the site, with very similar growth traits
(base growth temperature, turnover etc.) then an aggregate
functional group may be appropriate (this is the way Phygrow
1.0 and 1.2 worked.) An aggregate community model would
fall short of requirements if the results were to be used
for forage by a nutritional model that needed to know
how much of each species there were. An aggregate community
model would probably fail for dissimlar growth forms,
e.g. a site with 50% warm season grasses and 50% cool season
grasses could be simulated as an aggregate community of
temperate weather grasses, but at the time between
cool season and warm season the model would simulate
a healthy standing crop with deep roots, rather than
a dying crop of cool season grasses with deep
roots (that could reach water but not start new
growth due to temperature stress) and a new crop
of warm season grasses with shallow roots.
- Functional Group Modeling
- Functional group modeling provides the granularity to
model groups of species with similar growth forms as a unit.
An advantage this has over aggregate modeling is that each
functional group can have a different reaction to climate
changes and stresses. Functional
group models have the disadvantage of being site specifc,
and lager parameterization requirments (Parameterize x
functional groups raater than one aggregate.)
- Species Level Modeling
- Species level modeling will provide the most accuracy for
various plant/climate response, and if well parameterized,
allow for easy transition to other communities that contain
the same species. Species level modeling provides the
best breakdown of what a plant inventory should look like
for a site. Species level models need the greatest
level of parameterization.
- Species/Group Modeling
- The recommended approach will be to use a combination
of species level modeling and functional group modeling.
For any species that comprises 10% or more of the site
production, it is probably well worth the time it would
take to model it, while species at less than 10% should
be grouped into an "other" class or functional group.
Community Editor
Functional Group Editor