Plant-Soil Interactions With Fire
In this blog I will be discussing
plant-soil interactions that are caused by fire. Aldo Leopold is considered to
be the godfather of conservation and has left a major impact on the wildlife
techniques that we use today. Leopold had five wildlife management techniques.
These techniques were an axe, cow, plow, match, and a gun. Aldo Leopold once said, “Fire
has always been part and parcel of the evolutionary background of our present
species in many regions.” Prescribed fires are commonly used to promote
plant growth and set back succession. Wildfires are fires that are burning out
of containment and can have various intensities. While some people view fire as
a detrimental thing to the environment, it can be very beneficial. For example,
the Great Smoky Mountain wildfire destroyed many homes and businesses but it
could result in the betterment of some of the ecosystems that were burned. Many
plant species rely on fire for their existence. These plants have many
adaptations that help them survive these fires. A few of these adaptations
include serotinous cones and thick bark. Fires also clear debris from the
soil’s surface allowing for seeds to be in contact with bare mineral soil. Fire
can have a major impact on the environment in many ways. If you have never seen
an area that has recently been burned, then you are in for a treat. What was
once a place that was not anesthetically pleasing and covered in plant litter
becomes a magnificent field of green plants emerging from the ground. Fire
impacts plants and their soils in the environment through the change of plant
communities.
Before starting this blog, I would
like to inform my readers that this could quite possibly be my last blog post.
It has been a great journey throughout my years, but I have accepted a position
at Brewster’s Services Group to further my career in wildlife and fisheries.
A major factor that affects species
abundance and diversity is plant-soil feedback (Klironomos, 2002). Some of the
factors that promote plant invasion success are higher resource availability
and reduced competition (Davis et al. 2000). Fire is a type of disturbance that
has been suggested to facilitate plant success by interacting with belowground
soil biota (Blumenthal, 2005). Do you see the problem here? While fire as the
ability to promote desired species establishment, it also has the potential to
create an environment that is beneficial for invasive species. Fire doesn’t just
interact with the soil it can also create an environment that is beneficial for
invasive species. The intensity of the fire plays a major role in determining
how it impacts the ecosystem. Low intensity fires have a minor effect on
organic matter and soil structure, however high intensity fires can create temperatures
high enough to break down soil aggregates (Prosser & Williams 1998). Fire
can also affect physical and chemical soil properties. Fire intensity and
frequency have an effect on the amount of alteration of abiotic and biotic
factors (Debano et al. 1977). Fire can increase the amount of elements in the
soil. Some of the elements that fire increases are K, Mg, Ca, and Na. The
amount of phosphorus in the soil following a fire is variable. Fire can also
increase the amount of soil exchangeable Ca^2+ and Mg^2+ (Murphy et al. 2005). On
the other hand, a more intense fire can cause a significant change of woody
vegetation on the ecosystem (Langevelde et al. 2003). In 1966, the use of
prescribed burning was eliminated at Tall Timbers Research Station in Tallahassee,
Florida. After the first fifteen years of fire exclusion, the changes in
wildlife abundance and vegetation were obvious. The amount of groundcover
decreased from 85% to 21%, while the canopy cover increased from 43% to 91%
(Engstrom et al. 1984).
Fires can
be related to plant invasion. Even-though fires can improve plant invasion success;
studies have shown that fire can suppress the spread and establishment of
invasive plants (D’Antonio, 2000). Fire can be very beneficial to ecosystems,
but it has the potential to dramatically change the soil biota (Gonzalez-Perez
et al. 2004). Smith performed a study that showed the abundance of exotic
species was much higher in unburned sites than in sites that were burned every
year. A study performed by D’Antonio showed that prescribed burning decreased
the amount of invasive species in 20% of his trials. He looked at two types of
disturbances. A Type 1 disturbance removed only the aboveground flora, while a
Type 2 disturbance removed the aboveground and belowground biota. His study
showed that Type 1 disturbances facilitated plant invasion and Type 2
disturbances suppressed plant invasion.
Figure 1 shows the relative competitive ability that is
required for successful plant invasion under a disturbance that removed the aboveground
and belowground biota.
Figure 1.
Relative competitive ability
required for successful invasion under type II disturbances. The horizontal
axis represents natural mortality d. (a) Different
curves represent different values of the intensity δ. As δ increases,
the threshold value of relative competitive ability increases, implying a
stricter invasion condition. γ is fixed at
0.4. (b) Different curves represent different values of the disturbance
probability γ.
So why do we care about the plant-soil
interactions with fire? Some studies have shown that some invasive plants can
have a less negative soil feedback than native species (Inderjit et al. 2010).
If an area is disturbed by something like fire, then there is a chance that
that area can come back in invasive plants. And if an area consists of invasive
plants, then it is very difficult to eradicate those plants. It is suggested
that plant invasion can be facilitated by weakened negative soil feedback in
the new habitat (Turnbull et al. 2010). Physical disturbances, such as fire,
are important factors that can affect the success of plants (D’Antonio, 2000).
Fire can enhance or suppress the distribution and abundance of plant species
(Lockwood et al. 2007). If prescribed fire is used correctly, it has the
potential to promote desired plant species instead of invasive species.
My research on plant-soil
interactions with fire has given me a better understanding of how fire impacts
plants and soils. I have concluded that these interactions can be attributed to
three key points. 1) Fire can create conditions that are beneficial to many
plant species 2) Fire can create changes in the soil that can help promote
invasive species 3) Fire intensity can influence plant-soil interactions.
Fire impacts the environment through
the changes in plant communities. Fire can have a major impact on the
environment in both positive and negative ways. The use of fire has been used
as a management tool for hundreds of years. I have personally used prescribed
fires to burn around 2,000 acres, and I have seen how many ecosystems strive
after the application of fire. However, wildfires can create a problem for the
environment. I have found through my research that the changes in plant
communities are related to fire.
Literature Cited
D’Antonio C., Mooney R., Hobbs A. Fire, plant invasions, and
global changes (Eds.), Invasive Species
in a Changing World, Island Press, Washington, DC (2000), pp. 65–93
J.N. Klironomos Feedback with soil biota contributes to plant
rarity and invasiveness in communities Nature,
417 (2002), pp. 67–70
Inderjit, W.H. Van der Putten Impacts of soil microbial
communities on exotic plant invasions Trends
in Ecology & Evolution, 25 (2010), pp. 512–519
Fukano, F. Tackiki, Y. Soil disturbances can suppress the invasion
of alien plants under plant–soil feedback. Ecological Modelling, 260 (2013),
pp. 42-49
Debano, L.F., Dunn, P.H. & Conrad,
C.E. (1977): Fire's effects on
physical and chemical properties of chaparral soils. In: Proceedings of the
Symposium on the Environmental Consequence of Fire and Fuel Management
Ecosystems. ESDA Forest Service General Technical Report. WO-3, 65- 74.
Murphy, J. D., et
al. "Wildfire effects on soil nutrients and leaching in a Tahoe Basin
watershed." Journal of Environmental Quality 35.2 (2006):
479-489.
J. Lockwood, M. Hoopes, M. Marchetti Invasion Ecology Blackwell Publishing Ltd, Oxford (2007)
M.A. Davis, J.P. Grime, K. Thompson Fluctuating resources in
plant communities: a general theory of invisibility.Journal of Ecology, 88 (2000), pp. 528–534
D. Blumenthal Ecology. Interrelated causes of plant invasion Science (New York, N.Y.), 310 (2005), pp. 243–244
Prosser, Ian P., and Lisa Williams. "The
effect of wildfire on runoff and erosion in native Eucalyptus
forest." Hydrological processes 12.2 (1998): 251-265.
J.a. González-Pérez, F.J. González-Vila, G. Almendros, H.
Knicker The effect of fire on soil organic matter—a review. Environment International, 30 (2004), pp. 855–870
