Florida vegetation needs fire!

Thought I would add one more post about some productive prescribed burning in Florida.


Amazing that 70% of Florida's 9 million acres of conservation land depends on fire for survival. Naturally with fire suppression they saw many of their native species threatened and endangered. Now resource managers are trying a different approach with central Florida fire staff and fire staff from Spain, they are conducting prescribed burns at locations like the flatwoods on the preserve at Disney World. 

                                         Nature Conservancy


One of the many species of plants that is responding to these burns is the pitcher plant. There are several subspecies of the pitcher plant in Florida that are listed as endangered. Historically, these areas of Florida had frequent summer fires resulting from lightning. With fire suppression a succession of other plant species out-competes the pitcher plant. The prescribed fires are knocking back the growth of these competitive species and allowing the pitcher plant to resprout and flourish.

                                          Nature Conservancy


http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/florida/howwework/florida-restoring-fire-to-native-landscapes.xml

Resistance vs Resiliance

Resistance is how much a community changes due to a particular disturbance. An example of resistance could be dune grass communities. On a individual level, species with long roots may be more resistant to high wind disturbances then species with shallow roots. At a community level, plant communities that grow in dense mats will better anchor sand dunes in place than a population that is composed of widely spaced individuals.
Resilience is the plant community or individuals ability to come back after a disturbance event. If you have a highly resilient community,  its going to take more energy and factors involved to shift that community to an alternate stable state when compared to a community with low resilience. One factor that managers may consider is that disturbance may select for the more resilient and resistant indivisible in a plant community. Knowing what plant species will most likely survive and return after a disturbance will give land managers a better idea of what the post disturbance environment will look like.

A Long Time Coming...

Resilience is when an individual can be beaten down but still rise again; in this case plants that can be burnt down and still “rise from the ashes”, like a phoenix. Resistance is when an individual can withstand harmful things that come their way; again, in this case it’s fire. Being native plants to fire-prone areas, they've spent a long time evolving to be suited for the environment.

I think it’s important for people managing the forests and other fire-prone areas to keep these terms in mind, as well as the adaptions plants have to be describes ad resilient or resistant to fire.

An example of resilience is that some plants have the ability of below ground resprouting. This means that even if the plant is burned at the surface, if the fire isn’t too intense, the roots in the dirt would be shielded from harm and the plant can begin to regrow from those points that haven’t been damaged.

An example of resistance is the ponderosa pine, with thick insulating bark and self-pruning. The bark is thick enough to shield the tree from being exposed to too much heat. The self-pruning is when the tree “drops” its lower branches so when the underbrush and duff are burning, the fire most likely won’t get tall enough to catch the branches. This eliminates the “ladder fuel” meaning that the fire won’t have the opportunity to become a crown fire by burning up the tree.

Resilience and Resistance

Resilience is the capacity of an ecosystem to regain characteristic processes over time following impacts or disturbance. 

Resistance is the ability of an ecosystem to maintain characteristic processes despite the impacts or disturbances.

Resource managers will benefit from considering and implementing efforts to maintain both resilience and resistance. Resilience is lost when thresholds are crossed and an ecosystem can not return to its original state via natural processes following an impact or disturbance.
Resistance is the strength in an ecosystem to utilize biotic and abiotic factors and ecological processes in an ecosystem that will reduce or limit the impact of a disturbance. 

An example of resistance is an ecosystem's ability to limit the population growth of invasive species. The ecosystem's resilience will define the ecosystem's ability to maintain processes during the impact of invasive species.

http://greatbasin.wr.usgs.gov/gbrmp/docs/SD/11%20Chambers%20Winnemucca%20Workshop.pdf

Fire adaptations in Plants.

Fire-adapted plant species are species of plants that have, over time, developed traits that help to keep them safe from too much harm in fires.  Some plants seem to have adapted well to fires but what are seen as adaptations are actually exaptations.  Exaptations are characteristics that developed over time to make an organism more physically fit for a particular environment but end up being beneficial in a fire.  A couple of fire adaptations are listed below.

-Fire-activated seeds:  Some seeds need fire to allow them to sprout.  The lodgepole pine, Eucalyptus, and Banksia have cones that are completely sealed with resin and the heat of the fire melts the resin, releasing the seeds protected within.

-Thermal insulation:  I like this one.  Some plants create a thick layer of bark that allows them to survive a fire.  Larches and giant sequoias have very thick bark that can be directly burned without allowing harm to come to the vital parts of the tree.  The Australian grass tree and South African aloes keep dense, dead leaves around their stems to protect against fire.

We could all use some R&R

     Resistance is a plant's ability to survive a disturbance. Whether we are considering them adaptations or exaptations either way these characteristics allow for a plant to survive. Just as we have discussed some plant’s resistance to fire, others have resistance to flooding and can tolerate extremely wet conditions.

     Resilience is a plant species ability to return to a stable equilibrium after a disturbance. Though the plant itself may not survive, its future will.  I would compare this to my yard full of dandelions. Even though I don’t use chemicals, we feed a lot of dandelions to rabbits. I send my kids out to pick them quite frequently. My children would be the disturbance. Those dandelions have devised a sneaky trick to attract my children to them after they have flowered. They entice my children to spread their future generations of seeds all over the neighborhood because it is just way to much fun not to blow them apart. The dandelions always come back. This may not be spot on as far as a good example, but it helps me to separate the two in my mind.

     I think that building and maintaining resistance and resilience are great concepts to incorporate into natural resources as long as we are working with native species. My worry would be about adding new species which could cause state changes after the disturbance instead of maintaining previous phase changes.

Fire Facilitates Life

Few species possess true fire adaptation. Adaptation is the result of derived traits to a specific environmental pressure. For a species to be fire adapted, it must possess a feature borne only from the confluence of its progenitors with fire events. That feature must have imparted superior fitness to those ancestral plants which was then bequeathed to their offspring. Out of many clever plant adaptations, perhaps only two might qualify as fire adaptations: serotiny and smoke-assisted germination. The former needs fire to melt resins which seal seeds within their cones, while the latter needs the presence of smoke-vectored chemicals (NO2, karrikins, cyanohydrins) to break seed dormancy and induce germination. Strictly speaking there are different degrees of serotiny – weakly, strongly, facultative, or obligate – such that true fire adaptation might be constricted to serotinous obligates. Species such as Lodgepole pine (Pinus contorta) need heat from fires around 115˚ – 140˚ F to melt resins that fuse the scales of the cone shut.

Sealed Lodgepole pine cones.
Photo by Benkman Lab, University of Wyoming

Smoke induced germination is a widespread trait among the families Asteraceae, Ericaceae, Poaceae, and Fabaceae. Fires which burn around 320˚ – 390˚ F produce water-soluble compounds which, combined with flushes of fresh water, are thought to stimulate rapid germination in fire-affected landscapes. The species Black-eyed Susan (Rudbeckia hirta) and Coyote tobacco (Nicotiana attenuata) have been identified as smoke-sensitive forbs.

Black-eyed Susan
Photo by NRCS Plant Database

Coyote tobacco
Photo by Oregon State University

Serotiny and smoke-assisted germination are useful adaptations for re-populating fire-cleared landscapes. What better incentive for the next generation to develop than on the heels of that which killed its parents? With cues from smoke and heat, seeds can prime themselves for growth in the first clement weather. Thus one can see that fire is a force capable not only of dealing death, but facilitating life. 

Germination of Lodgepole pine
Photo by Benkman Labs, University of Wyoming

Regrowth after fire
Photo by US Geological Survey

The Resiliency of Resistance

 

 

The term "resistance" refers to the ability of an individual to withstand a disturbance. "Resiliency" denotes the ability of a species to regenerate after a disturbance. I think these concepts are important to the management of Natural Resources, as it allows us to analyze when we need to be proactive or passive in our attempt to eliminate wildfires. Areas  that harbor low-resistance plant life require extra attention to try and prevent unprescribed burns, such as removing potential surface fuels or trimming low-lying branches. In ecosystems with resilient plant life that is well adapted to fire regimes, allowing the plot to burn eliminates competition due to over-population and enables native species to thrive. 

Amazing Adaptive Species!

A fire adapted species is a flora or fauna that can survive and thrive in the presence of fire invading their habitat. One such example would be the Giant Sequoia/Giant Redwood (Sequoiadendron giganteum). By volume, these trees are the largest in the world. With a diameter up to 26' and a height of up to 279', the thick bark of the tree is fibrous and can be up to 3' in thickness so it can protect the cambium of the tree. Even though it is injured, most full grown Sequoias can survive this kind of damage. Although there are many trees that have bark to protect it from fire, a high intensity , low frequency fire can cause far more damage compared to a low intensity, high frequency fire that mostly effects the understory. 

Fire scar on the bark of a Giant Sequoia. 

A second example of a fire adaptation would be the what the Louisiana Pinesnake (Pituophis ruthven) does, as well as rodents, rabbits, lizards, other snakes, turtles and many other animals. These forest creatures have adapted to high frequency, low intensity forest fires by burrowing into the ground for protection. Unfortunately due to fire suppression, the Louisiana Pinesnake is losing its habitat. With infrequent fires to remove the mid-story, the high intensity and low frequency fires overtake and kill the understory. It destroys the vegetation that pocket gophers (Thomomys bottae) depend on as their food source. When the gophers relocate to find other food sources, that leave the snakes without a food source or a way to burrow.  

http://www.britannica.com/list/5-amazing-adaptations-of-pyrophytic-plants

http://news.nationalgeographic.com/news/2013/08/130826-giant-sequoias-yosemite-rim-fire-forestry-science/

https://www.nps.gov/fire/wildland-fire/learning-center/educator-resources/lesson-plans/fire-adaptation.cfm

https://www.nwf.org/Wildlife/Wildlife-Library/Amphibians-Reptiles-and-Fish/Louisiana-Pine-Snake.aspx

Resistance and Resilience

resistance-"the ability not to be affected by something, especially adversely"

resilience- "the capacity to recover quickly from difficulties; toughness"

These two term in my opinion are very useful when thinking about natural resource issues. When taking away from an environment for economic reasons, it is important to make sure that the species  that is being removed can also be resilient enough to recover and resistant enough to not be affected to much by the loss over volume. When we are working with natural resources it is important to make sure that they are renewable and "resilience and resistance" are two major factor on whether or not a resource will be able to handle being harvested and at what level they can be harvested. 

Because these terms are very broad it is hard to pin down the exact meaning of them. This being said it also helpful when working in terms of ecology. There are many reasons why resistance and resilience are important depending on how you look at them. 

www.merriam-webster.com/dictionary

A stronger ecosystem

When thinking in terms of ecology, the simplest way to define resilience and resistance is as follows:

resilience: the capacity to recover quickly from difficulties

resistance: the ability not to be affected by change. 

These simple definitions are just a fraction of the meaning these words hold. These two terms are very important to ecology and to the preservation of our natural environment. With resilience we have the ability to recover from damages, such as fires, flooding, earth quakes, ect. This is important for an ecosystem to be able to bounce back after prevents disaster.  

Resistance prevents the ecosystem from being effected at all from any sort of change or damages. This usually comes about after first being exposed to damages in the first place, like fire clearing out a pine forest. After a time, some areas will become stronger against devastations. Thus, the ecosystem evolves to become stronger against change. 

Fire Adaptations

Fire adapted species can be either plants or animals.  They have adapted a trait or have traits that allow them to reproduce or regenerate after a fire.  A few examples of fire adaptations for plants are resprouting and bud protection, and thick bark.  

Photo by mountainphotography.com

Quaking Aspen, considered a pioneer species because it is one of the first vegetation that will dominate an area after a fire, resprouts after a fire from its root system.  Since the buds are underground, they are protected from any damage caused by a fire.  

Photo by cordellmandersen.com

Longleaf pine is a tree that is able to reproduce after certain fires because the buds are protected by the long, moist needles.  They can withstand low intensity ground fires for two reasons.  One of which is because the fire does not come to the crown of the tree and is not hot enough to affect the bud (seed). When the fire gets close, the moist needles vaporize and the steam puts out the fire.   

Photo by Irisha on Flikr (2016)

Photo by getdomainvids.com

The other reason is because the Longleaf pine also has fire resistant (thick) bark which protects the growing tissue from heat and flakes off as it burns.

Sources:

 

Hilty, John. Illinois Wildflowers. Quaking Aspen – Populus Tremuloides. 2002-2015. http://www.illinoiswildflowers.info/trees/plants/quaking_aspen.html. 25 April 2016.

Kuhlmann, Ellen. Washington Native Plant Society Blog. Botanical Rambles. Plant Adaptations and Fire. 2015. https://www.wnps.org/blog/plant-adaptations-and-fire/ 25 April 2016.

Nix, Steve. About Education. Longleaf Pine, a Common Tree in North America. 2016.http://forestry.about.com/od/conifers/tp/Pinus_Palustris.htm 25 April 2016.

U.S. Department of the Interior. National Park Service. Fire and Aviation Management – Learning Center. 2016. https://www.nps.gov/fire/wildland-fire/learning-center/educator-resources/lesson-plans/fire-adaptation.cfm. 25 April 2016.