Agriculture Reference
In-Depth Information
3
Fire-related Plant Traits
As illustrated in
Fig. 2.1
there are four environmental parameters that are necessary
to determine the distribution of fire-prone ecosystems. However, they are insufficient
to predict ecosystem responses to fire without a detailed understanding of the fire
regime (see
Fig. 2.7
). Different fire regimes have very different potentials for recovery
and place very different premiums on specific plant traits. For example, those traits
contributing to the persistence of species in crown fire regimes will often be very
different from those in surface fire regimes. In short, organisms are not adapted to fire
per se
, but rather to a particular fire regime. Plant traits that are adaptive in fire-prone
environments are discussed here. The evolution of such traits and the extent to which
they represent adaptations to fire are considered in
Chapter 9
.
Plant populations exhibit four modes of recovery following fire:
(1) endogenous regeneration from resprouts or fire-triggered seedling recruitment,
(2) delayed seedling recruitment from postfire resprout seed production,
(3) delayed seedling recruitment from
in situ
surviving parent plants, or
(4) colonization from unburned metapopulations.
These regeneration modes apply to mediterranean-type climate (MTC) ecosystems
as well as non-MTC ecosystems and generally sort into vegetation types with
different fire regimes, and there is some degree of convergence in regeneration
modes between plant communities with the same fire regime. Plants adapted to
crown fire regimes typically recover from fire by a combination of endogenous
regeneration from seedlings and resprouts as well as delayed seedling recruitment
from resprout seed production. In contrast, in surface fire regimes the dominant
tree species depend on survival of parent seed trees for seedling recruitment during
early succession, and the understory species recover by combination of coloniza-
tion and endogenous regeneration.
Endogenous Postfire Regeneration
Resprouting
Resprouting
refers to the initiation of new shoots, usually from existing meristems
in woody plants, following fire or other disturbances. This term is preferable to
