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Breeding Bird Survey, 2015

How are the birds doing? Ever since Rachael Carson revealed in the 1960s that pesticides were decimating bird populations, how the birds are doing has been an important question. DDT was the worst-offending pesticide, and it was soon banned, but other chemicals and other factors affect the ability of birds to survive. These days, the most important may be habitat destruction, competition from invasive species, and the effects of other chemicals, such as lead.

Many, many bird species migrate. Those that do require habitats along the way where they can rest and refuel. Break the chain of habitats in even one place, and you seriously harm the ability of the birds to survive.

Figure 1. Breeding Bird Survey Routes. Source: Sauer et al, 2017.

The largest and most important survey of bird populations is the Breeding Bird Survey, which has been conducted every year since 1966. Here’s how they conduct the survey: during peak breeding season, starting 1/2-hour before sunrise, volunteers follow a route with 50 stops, each stop at least 1/2 mile apart. The route stays the same from year-to-year. The volunteer counts all birds of that species seen or heard within a quarter mile of the stop. Figure 1 shows a map of the routes. The routes look like blue dots because of the scale of the map. You can see that coverage of the USA is quite good.

From the multiple routes in each geographical area, for each species a yearly index is constructed. These indexes represent “the mean count of birds on a typical route in the region for a year.” (USGS, Patuxent Wildlife Research Center)

The results are mixed, differing from species-to-species and from region-to-region. As you might expect, even though the routes have 50 stops on them, and the method used is quite rigorous, it is not the same as physically being able to count every bird. Some of the birds may not be calling when the volunteer is there, or they may be hidden in brush, etc. The survey method does not permit a calculation of the absolute number of birds in a region, and the annual index is only reliable if a sufficient number of birds are observed. Thus, the Breeding Bird Survey provides crucial data, but it may be only part of the picture.

Table 1. Breeding Bird Survey Trend Estimates for Bird Species Observed in Missouri. Data source: Sauer, et al. 2017.

Trend data on how the annual indices for each species have changed is available for every species and for every state and region. I shall focus only on observations in Missouri. Table 1 shows the data. The trends are reported from 1966-2015 and from 2005-2015. The trends represent the annual rate of change over the period of interest.

(Click on table for larger view.)

The table is a bit complex, so let’s unpack it. It shows all species observed in Missouri. They are listed in order of the change between 1966 and 2005, with species that declined on the left side, and species that increased on the right. Each side of the chart begins with 4 columns intended to comment on the quality of the data for a given species. They are coded “G”, for green, or good, “Y” for yellow, or caution, and “R” for red, or extreme caution. The first column comments on the credibility of the measurement. The second column comments on the size of the data sample. The third column comments on how precise the measurements are. The fourth column comments on the relative abundance of the species.

The trend statistics follow the names of the species, and they are color-coded with green and red bars, representing the size of the change. Readers of this blog know that time series are vulnerable to year-to-year variation, but the fact that these are trends computed over the entire period of measurement should minimize that effect.

Between 1966 and 2015, annual indices for 58 bird species decreased, while 79 increased. If one counts only species for which the Regional Credibility Measure was “G,” then the situation is reversed: 40 species decreased and 31 increased.

Those with declines of more than 5% were the blue-winged teal, the loggerhead shrike, the house sparrow, and the American bittern. The blue-winged teal declined at a rate of 18.1% per year, however the Regional Credibility Measure for that species is red, indicating that use and interpretation of the data for that species warrants extreme caution. The same is true for the American bittern. The Regional Credibility Measures for the loggerhead shrike and house sparrow, however, are good.

Because 1966-2015 is a 49 year period, even small annual changes can accumulate to rather significant changes across the entire period. Any decline of 1.4% per year over 49 years would result in a 50% decline over the whole period. The loggerhead shrike, for which the Regional Credibility Measure is “G,” declined at an annual rate of 6.68% per year. Over 49 years, that computes to a decline of 97%!

Among the success stories are some birds that are everybody’s favorites: bald eagle observations increased almost 40% per year, great egret observations increased almost 11%, and cedar waxwing observations increased almost 9%. With the bald eagle and great egret, however the Regional Credibility Measures are red, again indicating extreme caution in using and interpreting the data, and for the cedar waxwing it is yellow.

These findings reinforce what was stated above: the Breeding Bird Survey provides crucial data, but it may not be a complete picture.

Missouri is home to 9 federal wildlife refuges and hundreds of state conservation areas. All are devoted to providing animals and plants the habitat they need to survive. If you visit them on the wrong day, they often look empty, and you can come away wondering what the big deal is. If you visit them on the right day, however, they can be teeming. Figure 2, for instance, shows the afternoon lift-off of a flock of snow geese at Loess Bluffs NWR in northwestern Missouri. The snow geese are only there to rest and refuel for a few days each spring and fall.

Figure 2. Snow Geese Lift Off at Loess Bluffs NWR. Source: Keyserill, 2017.

Sources:

Keyserill, Robert. 2017. “Afternoon Lift Off.” Source: U.S. Fish and Wildlife Service. “Loess Bluffs National Wildlife Refuge.” Downloaded 3/18/2018 from https://www.fws.gov/refuge/Loess_Bluffs.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr, K. L. Pardieck, J. E. Fallon, and W. A. Link. 2017. The North American Breeding Bird Survey, Results and Analysis 1966 – 2015. Version 2.07.2017 USGS Patuxent Wildlife Research Center, Laurel, MD. Downloaded 3/14/2018 from https://www.mbr-pwrc.usgs.gov/bbs.

Siolkowski, Dave, Jr., Keith Pardieck, and John Sauer. 2010. “On the Road Again for a Bird Survey that Counts.” Birding, 42, (4), pp. 32-40. Downloaded 3/18/2018 from https://www.pwrc.usgs.gov/bbs/bbsnews/Pubs/Birding-Article.pdf.

United States Geological Survey, Patuxent Wildlife Research Center. Trend and Annual Index Information. Downloaded 3/19/2018 from https://www.mbr-pwrc.usgs.gov/bbs/trend_info15.html.

Missouri Species of Concern 2018

Many species have dwindled to the point that their continued survival is an issue of concern. So says the most recent edition of the Missouri Species and Communities of Conservation Concern Checklist. The checklist monitors the status (in Missouri) of:

  • 18% of all vascular plants (plants with a specialized system to conduct nutrients throughout the plant, including almost all trees and flowering plants);
  • 14% of all non-vascular plants (plants without a specialized circulatory system, including mosses and algae);
  • 28% of all vertebrate animals (animals with a backbone, including fish, snakes, birds, rodents, cats, dogs, bear, and deer); and
    an unknown percentage of native invertebrate species (animals lacking a backbone, including insects, worms, and shellfish).

Species have become threatened despite the fact that, legally at least, “All native animal species in the State of Missouri are protected as biological diversity elements unless a method of legal harvest, harm or take is described in the Code. All native plant species in the State of Missouri are protected as biological diversity elements only on land owned by the Missouri Department of Conservation.” (Missouri Department of Conservation 2018)

Figure 1. Data source: Missouri Department of Conservation 2018.

Threatened or endangered species in Missouri are defined as those listed as such by the Missouri Wildlife Code (3 CSR 10-4.111), or the U.S. Endangered Species Act. There are 75 listed in the checklist. They include such notable species as the Peregrine Falcon, the Greater Prairie-chicken, and the Snowy Egret.

There are many, many more species of concern that are not listed in those laws, however. The report lists 1,156 in total. Figure 1 shows the number of species by rank. (Some species carry more than one rank, thus, the total number of rankings is larger than the total number of species on the list.) Some of these species may exist in other parts of the country or the world, but some are (were) unique to Missouri.

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Figure 2. Data source: Missouri Department of Conservation 2018.

Plants and animals tend to group together into communities where the species each fit into a niche that contributes to the health of the whole community. Weaken one and you weaken the whole community. Because Missouri’s landscape is fractured into relatively isolated ecosystems defined by soil type, sunlight, and the presence (or absence) of water, the state is home to many unique, but small communities of this kind. Many of Missouri’s threatened species live in such communities. Eighty-five such communities have been identified by the Missouri Department of Conservation. Of them, 24 are listed as imperiled (28% of the total), and 17 more are listed as critically imperiled (20% of the total). Together, that means 41 are either imperiled or critically imperiled (48% of the total). (Figure 2).

Sources:

Consolidated State Rules of Missouri. 2017. 3 CSR 10-4.111, Wildlife Code, Endangered Species. Viewed online 2/15/2018 at https://www.sos.mo.gov/adrules/csr/current/3csr/3csr.asp.

Missouri Department of Conservation. 2018. Missouri Species and Communities of Conservation Concern. Publication # SC1077. Downloaded 2/15/2018 from https://nature.mdc.mo.gov/sites/default/files/downloads/2018_SOCC.pdf.

California Ablaze: Nature’s Revenge?


Fires torch hundreds of thousands of acres in California.


Just a few short weeks ago I discussed the terrible hurricanes that affected Houston, the Caribbean Islands, and Florida this year. Now, the headlines are full of the wildfires that have been raging in California.

By late September, it had already been a heavy forest fire season in the western United States. Then, over the weekend of October 7-8, wildfires broke out in the area around the Napa and Sonoma Valleys. Fanned by hot, dry winds, they spread unbelievably quickly, burning 155,509 of acres (as of 10/17/2017), including prime wine producing vineyards, and thousands of homes (CALFIRE 2017b). Dozens were killed. Figure 1 shows the Coffee Park area of Santa Rosa in 2015. Figure 2 shows it after the fire. The gray areas are homes that have been burned – I mean burned to the ground, reduced to ashes. (City of Santa Rosa 2017)

Figure 1: Coffee Park Neighborhood, Santa Rosa CA, in 2015. Source: City of Santa Rosa.

Figure 2. Coffee Park Neighborhood, Santa Rosa CA, after the fire. Source: City of Santa Rosa.

 

 

 

 

 

 

 

 

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All totaled, as of 10/15/2017 CALFIRE lists 7,980 fires in California that have burned 1,046,995 acres (1,636 sq. mi.) (CALFIRE 2017b). Figure 3 shows a map of the fires. Maps such as this one tend not to be comprehensive, as they map the fires to which the specific agency has responded. (CALFIRE 2017a) Across the United States, as of 10/17/2017 there have been 51,435 wildfires that have burned 8,769,877 acres. That puts 2017 among the top 10 fire years ever, and compares to an average of 6,016,599 acres from 2006-2016. Figure 4 shows the data. Data collection methods changed after 1984, which is why I have used different colors for before and after that year. (National Interagency Fire Center)

Figure 3. Fires Responded to by CALFIRE in 2017. Source: CALFIRE, 2017.

Figure 4. Data source: National Interagency Fire Center, 2017.

 

 

 

 

 

 

 

 

 

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At a recent workshop of wildland fire experts, the consensus was that the United States was experiencing wildland fires that were behaving in aggressive, destructive ways that had never been experienced before. (National Academy of Sciences, Engineering, and Medicine 2017) What is going on?

In a series of posts last year, I explored the role that wildfire plays in western forests and showed that, though the number of fires did not seem to be trending higher, the number of acres burned per fire did. The result was that more acres per year were burning. There seemed to be 3 causes. One was that, while for decades fire was regarded as an unmitigated evil and suppressed as vigorously as possible, it was now regarded as a necessary part of forest ecology, and was allowed to burn without suppression efforts in some cases. A second reason was that decades of suppression had left western forests littered with dead and downed wood, perfect conditions for small fires to grow into huge raging crown fires that destroyed tens of thousands of acres. And a third reason was that climate change had raised summer temperatures, causing forests to dry out earlier in the season, turning small fires that would extinguish on their own into large, destructive fires.

Early fall is the driest time of year in the regions around the Napa and Sonoma Valleys. Typically, it has rained very little or not at all since March or April; the grasslands are brown and sere, the forests dry and brittle. Then, in October, the wind starts to blow: the Diablo Winds in Northern California, and the Santa Ana Winds in Southern California. Fueled by high pressure over the central United States and lower pressure over the coast, the winds rush over the Sierra Madre Mountains, down the passes and valleys, and through the lowlands. It happens every year. This year, when the fires started near the Napa and Sonoma Valleys, gusts were blowing at 79 m.p.h. Recent research suggests that the winds may be getting hotter and drier as a result of climate change. (Fountain, 2017)

Wildfire needs three things to grow, and it got all of them: warm temperatures, lots of dry fuel, and high winds that were hot and dry. The fires blew up into raging infernos. Blowing sparks along at 70+ m.p.h., the wind and the fire outraced the firefighters. In a span of only a few hours, tens of thousands of acres were reduced to ashes, whole neighborhoods were destroyed, and dozens were killed.

Hurricanes in the Atlantic, fires across the West, deluges and record heat in Australia, terrible floods in Asia, drought and desertification in some parts of Africa and floods in other parts: is Mother Nature mad at us? Is she exacting revenge for the way we have mistreated Her all these years? To borrow a thought from Abraham Lincoln: if we shall suppose that environmental destruction is an offense against Nature, and that humankind has caused that offense, and that suffering inevitably comes to those who commit such offenses, and if Nature now gives to us these terrible disasters as due to those who have caused the offenses, then shall we see in them anything but a judgment and a justice that is altogether true and righteous? “Woe unto the world because of offenses.” (Lincoln, 1865)

Sources:

CALFIRE. 2017a. Incident Information: Number of Fires and Acres. Viewed online 10/17/2017 at http://cdfdata.fire.ca.gov/incidents/incidents_stats?year=2017.

Cal Fire. 2017b. Statewide Fire Maps. Downloaded 2017-10-17 from http://www.fire.ca.gov/current_incidents.

City of Santa Rosa. 2017. Emergency Information Homepage: Fire Aerial Photo Comparison. Downloaded 2017-10-17 from https://www.srcity.org/2620/Emergency-Information.

Fountain, Henry. 2017. “California Winds are Fueling Fires. It May Be Getting Worse. New York Times, 10/11/2017. Viewed online 10/17/2017 at https://www.nytimes.com/2017/10/11/climate/caifornia-fires-wind.html?action=click&contentCollection=climate&region=rank&module=package&version=highlights&contentPlacement=1&pgtype=sectionfront.

Lincoln, Abraham. 1865. Second Inaugural Address. Viewed online 10/17/2017 at http://www.bartleby.com/124/pres32.html.

National Academies of Sciences, Engineering, and Medicine. 2017. A Century of Wildland Fire Research: Contributions to Long-term Approaches for Wildland Fire Manage- ment: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: https://doi. org/10.17226/24792. Downloaded 8/25/2017 from http://nap.edu/24792.
National Interagency Fire Center. Year-to-Date Statistics. Viewed online 10/17/2017 at https://www.nifc.gov/fireInfo/nfn.htm.

Area Burned by Wildfire Doubled by Climate Change


Climate change has more than doubled the yearly area burned by wildfire in the United States.


In the decade from 1985-1994, wildfire burned 3,041,549 square miles in the USA. In the decade from 2006-2015 it burned 6,991,669 square miles – more than twice as much (see Wildfires Growing in Size, Not Number). But the number of fires has not greatly changed, rather the size of individual fires has grown. My findings parallel the results of several scientific studies and also field reports from the fire fighters themselves: wildfires, especially in southern and western mountain regions, have grown larger and more fierce. Why?

Using data to explore the change is complicated by the fact that the human response to wildfire has changed: instead of suppressing every fire as rapidly as possible, some are allowed to burn to fulfill their natural role in the forest ecosystem. It was during the 1960s that evidence of the beneficial role of fire began to accumulate, and it was during the 1970s when a change in policy began to be discussed. Yellowstone was the test site for the new policy, and it was phased in during the early 1980s. The terrible fires of 1988 changed all that, and the policy was suspended for review. It was reinstated during the early 1990s, and then it spread to other regions of the country The result was that the change occurred gradually, and not everywhere at the same time. The mid-1980s through 1990s are precisely the time of greatest increase in wildfire size. Thus, it is possible that part of the reason relates to the change in fire suppression policy. I know of no way to untangle that possibility from the data.

The change in policy notwithstanding, two other explanations are generally put forward to explain the increase: a build-up in fuel load due to the nearly century-long policy of suppressing wildfire, and climate change. The most recent studies suggest both play a role.

In Renewal by Fire I described how lodgepole pine forests age and become unhealthy if all fires are suppressed. To release their seeds, they require fire to melt the resin sealing their pine cones shut. In the absence of fire, little grows on the forest floor. Instead, downed timber builds up, forming conditions that are ripe for a large, destructive fire. Other western forests, dominated by species such as ponderosa pine or piñon pine, have different dynamics, but the effect is much the same: in the total absence of fire, fuel builds up, making conditions ripe for a severe, destructive fire.

Figure 1. Biomass Volume in Western States. Source: Rummer et al. 2003.

Figure 1. Biomass Volume in Western States. Source: Rummer et al. 2003.

I could find no studies that compare the fuel loads in America’s western forests over time. I did find one study that suggested that across 15 western states there were 6.9 billion bone dry tons of fuel in the forests, of which 2.2 billion (32%) should be removed. This assessment counted not only debris on the forest floor, but also trees that should be thinned. Figure 1 shows the data.

(Click on chart for larger view.)

There may be questions about this explanation, however. The near-century of fire suppression would lead to a gradual build-up in fuel load over the entire period, rather than a sudden spike in the 15 years from 1985-2000. In addition, in recent years some fires have burned through areas burned in previous fires. For instance, this year’s Maple Fire in Yellowstone National Park partially burned through areas that burned in the North Fork Fire of 2008. Until recently, fires had difficulty burning through areas that had burned previously, there just wasn’t enough fuel. Not so in recent years. Thus, a build-up of fuel load due to fire suppression doesn’t fit the shape of the data well, and it doesn’t account for some recent fire behavior.

Weather (short-term) and climate (long-term) are typically thought to be the most significant controls over the number, size, and ferocity of wildfires. As noted in Smokers, Smolders, and Big Blowups, it is when fuel becomes very, very dry that the fire danger becomes most extreme. Fires start more easily, and they wait only for a windy day to become raging infernos.

Climate change can dry the fuel in forests three ways: it can result in less precipitation, it can cause the snowpack to melt earlier, leading to a longer dry season, and it can raise the temperature, causing the moisture in the forest to evaporate faster. All 3 seem to be occurring.

There are no data regions that correspond precisely with the areas of Wyoming and Montana that include Glacier, Yellowstone, and Grand Teton National Parks. Instead, I will share data from sub-regions and/or specific locations that we can take as representative of the whole area.

Scientific studies of the snowpack sometimes look at the flow of rivers that depend on snowmelt for their water. They use the date of maximum flow as a proxy for the date of the snowmelt. They typically show that maximum flow is occurring earlier in the year than it used to, suggesting the snowpack is melting earlier than it used to. (Westerling et al, 2006)

I am not interested in when the snow is melting the most, however. I’m interested in the date at which snow no longer covers the ground, and thus, is no longer available to moisten the ground. I know of no data set that reports this information. Instead, I have selected a date late in the season – April 15 – and looked at the snowpack on that date over time. If there is less snow on the ground late in the season, it probably indicates an earlier date when the snowpack is gone and the dry season begins.

Figure 2. Snowpack at 4 Locations in the Northern Rockies. Source: Natural Resources Conservation Service.

Figure 2. Snowpack at 4 Locations in the Northern Rockies. Source: Natural Resources Conservation Service.

Figure 2 shows the data. Because the amount of snow can vary greatly according to local variables, I have taken measurements from the SNOTEL stations at Grassy Lake in Grand Teton National Park, Beartooth Lake in Yellowstone National Park, Emery Creek in the lowlands of Glacier National Park, and Flattop Mountain in the highlands of Glacier National Park. I have averaged the readings from 1981-2016, 1981 being the earliest measurement at two of these locations. The blue columns represent the actual data, and the black line represents the trend. You can see that since 1981 the average snowpack at these locations has declined, but the change is very small: -0.02 inches per year. Since the chart covers 36 years, that represents a change of -0.72 inches, or 3%. It suggests that the snow free date may have shifted a few days earlier, but by itself it is probably not a large enough change to account for the increase in fire.

Figure 3 shows the annual average winter temperature in Western Montana from 1981 to 2016. Figure 4 shows similar data for summer. The purple lines show the actual readings, the blue lines show the trends. You can see that the winter temperature has increased significantly, at a rate of 0.4°F per decade. You can also see that the summer temperature has increased even more, at a rate of 0.7°F per decade. That is a very large change for such a fundamental climate variable.

Figure 5. Winter Temperature in Western Montana. Source: Climate at a Glance.

Figure 5. Winter Temperature in Western Montana. Source: Climate at a Glance.

Figure 6. Summer Temperature in Western Montana. Source: Climate at a Glance.

Figure 6. Summer Temperature in Western Montana. Source: Climate at a Glance.

 

 

 

 

 

 

 

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Figure 5 shows the total winter precipitation in Western Montana from 1981 to 2016. Figure 6 shows similar data for summer. The green lines show the actual measurements, the blue lines show the trends. During winter, precipitation has increased marginally, at a rate of 0.10 inches per decade. However, during summer, precipitation has declined at a much higher rate: -0.65 inches per decade, about 6.5 times larger than the winter increase.

Figure 3. Winter Precipitation in Western Montana. Source: Climate at a Glance.

Figure 3. Winter Precipitation in Western Montana. Source: Climate at a Glance.

Figure 4. Summer Precipitation in Western Montana. Source: Climate at a Glance.

Figure 4. Summer Precipitation in Western Montana. Source: Climate at a Glance.

 

 

 

 

 

 

 

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The data suggest that precipitation in the region may have increased slightly during the winter, but it has decreased significantly during the summer. During both periods, the temperature has increased significantly, with the larger increase occurring during summer. The effect would be that reduced summer precipitation and increased temperature would result in significantly drier conditions during the summer. In addition, the higher temperature would affect fire conditions by raising the ambient temperature. This is probably a less important factor than dryness, but it is significant nonetheless. Thus, we would expect fire season to begin earlier, as the forest dries earlier in the year, and we would expect that as the fire season goes on, fires behavior would become extreme, as the forest becomes extremely dry and hot. And this seems to be what has happened.

As noted in the previous post, data suggests that wildfire acreage burned in Missouri may not have increased in the same way it has in the western forests. Some data suggests that there has been an increase, but other data suggests that the increase comes from an increase in prescribed burns, not from nature-caused fires. In general, Missouri wildfire requires a human cause and human intervention to spread. Thus, it is unlikely to be affected by climate change in the same way as is fire in the western forests.

A recent research paper confirms the analysis here: fuel in the western forests has, indeed, become significantly drier in recent decades, and human-caused climate change is responsible for more than half of the increase. The increased dryness has more than doubled the area burned by forest fires from what would be expected without climate change. (Abatzoglou and Williams, 2016.)

Wow.

Sources:

Abatzoglou, John, and A. Park Williams. 2016. “Impact of Anthropogenic Climate Change on Wildfire Across Western US Forests.” Proceedings of the National Academy of Sciences. Downloaded online 10/17/2016 from www.pnas.org/cgi/doi/10.1073/pnas.1607171113.

National Interagency Fire Center. 2016. Total Wildland Fires and Acres. Data downloaded 10/3/2016 from https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html.

Rummer, Bob, Jeff Prestemon, Dennis May, Pat Miles, John Vissage, Ron McRoberts, Greg Liknes, Wayne Shepperd, Dennis Ferguson, William Elliot, Sue Miller, Steve Reutebuch, Jamie Barbour, Jeremy Fried, Bryce Stokes, Edward Bilek, and Ken Skog. 2003. A Strategic Assessment of Forest Biomass and Fuel Reduction Treatments in Western States. U.S. Forest Service. Downloaded 10/15/2016 from http://www.fs.fed.us/research/pdf/Western_final.pdf.

Vautard, Robert, Julien Cattiaux, Pascal Yiou, Jean-Noel Thepaut, and Philippe Ciais. 2010.”Northern Hemisphere Atmospheric Stilling Partly Attributed to an Increase in Surface Roughness.” Nature Geoscience, 10/17/2010. DOI: 10.1038/NGE0979. Macmillan Publishers. Accessed online 10/14/16 from http://www.nature.com/articles/ngeo979.epdf?referrer_access_token=swKTAeDzYW4Kl15-TdbsINRgN0jAjWel9jnR3ZoTv0P_XZlZh9_0kSsrMp3iDVwubdoqNb5x1ysMj6Pi8WEDIGybf8d5YnWrK_K0z-rv-P5kg3zf4Xp2N303GmtI-sb1Pqxj-EgEPD2e8yP4zFLMB7MsVO75vxb45IdLL-6IGgaNxzUO-R2JVCJEQqMBo_ss1gYX8sILyKMpm8pnuA4OUXwG6FbEqe3OWYcb0RYdRPU%3D&tracking_referrer=www.nature.com.

Westerling, A.L., H.G. Hidalgo, D.R. Cayan, and T.W. Swetnam. 2006. “Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity.” Science, 313:5789, pp. 940-943, 7/18/2006. Downloaded 10/17/2016 from http://science.sciencemag.org/content/313/5789/940.full.pdf+html.

Missouri Wildfire Statistics


Wildfire statistics for Missouri confirm how different wildfire is here compared to wildfire in the national parks and forests of the Northern Rockies.


Wildfire statistics for Missouri are kept by two agencies: the National Interagency Fire Center (NIFC), and the Missouri Department of Conservation (MDC). Let’s look at the NIFC data first.

Data source: National Interagency Fire Center.

Data source: National Interagency Fire Center.

Most wildland fire in Missouri is either started by humans or requires human intervention to spread significantly (see previous post). The NIFC data calls fires that were not prescribed “wildland.” Figure 1 shows the number of square miles burned by wildland fire (blue) and prescribed fire (red). I have dropped linear regression trend lines on the data (the dashed lines).

You can see that the number of acres burned in wildland fires has varied widely, from a minimum of 1,660 in 2013 to a maximum of 55,395 in 2011. The number of acres burned in prescribed fires has also varied widely, from a minimum of 6 in 2003 to a maximum of 95,268 in 2009. In contrast to much of the rest of the country, Missouri does not appear to be experiencing an increase over time in the number of acres that were burned in wildland fires – the trend is basically flat. For acres burned in prescribed fires, however, there was a significant increase until 2011, and since then the number of acres has slowly decreased. Over the 13 years with data, wildland fires burned an average of 24,209 acres per year, and prescribed fires burned an average of 38,078 acres per year. Thus, for every 2 acres burned by wildland fires, more than 3 were burned by prescribed fires.

The number of acres burned by wildfire in Missouri is somewhat lower than in many western states. This year, 4 wildfires burning in Wyoming each burned more than 20,000 acres, and the Maple Fire by itself burned 45,425 acres. In California this year, the Soberanes Fire burned 132,127 acres.

The fire data from the NIFC includes fires managed by federal agencies (in Missouri principally the National Park Service, the U.S. Fish and Wildlife Service, and the U.S.Forest Service). It also includes a subset of fires managed by state agencies, although what is included in the subset is not clear. MDC’s data seems to come from fire reports by local and regional fire departments. Those reports appear to be voluntary, and I couldn’t find any guidance about what the local departments file reports on. I did notice that the data included reports from departments that were the primary responders to fires, and from departments that were assisting responders to fires. Thus, there could be duplication in the data, as well as inconsistencies from year-to-year in the participating departments. It is also unclear what lands are included (state lands? private lands? developed lands? undeveloped lands?). For these reasons, I can’t use MDC’s data to indicate either the absolute number of fires in Missouri, nor their trend over time in acreage burned. The data do indicate the cause of the fires. Despite the possible inconsistencies in the data, it seems to me that they can be used to give a rough indication of the causes of fire in Missouri, especially if summed over a number of years.

Data Source: Missouri Department of Conservation.

Data Source: Missouri Department of Conservation.

Figure 2 shows the percentage of Missouri fire from each cause from 2006-2015. The largest category is Unknown. After that, however, the largest category is Debris. This is where somebody burns something – a pile of brush they cleared from their land, some construction waste, etc. – and the fire escapes. The next largest category is Arson. Lightning accounts for only 1% of the fires counted by MDC. Dry lightning is common in the West (lightning from a thunderstorm that drops no rain), and it accounts for about 2/3 of western wildfires. It is rare in Missouri, however. In addition, Missouri’s overall climate is wetter and more humid. A lightning strike may cause a single tree to burn, but it rarely spreads into a significant fire.

I wish that the Missouri Department of Conservation’s data included a description of what the data counts. Despite repeated attempts, the director of their fire program and I have been unable to connect with each other, so I haven’t been able to clarify it.

The next post will explore why western wildfires have become larger and fiercer in recent years.

Sources:

InciWeb Incident Information System. This is a data portal. To find wildfires in Wyoming, I selected “Wyoming” in the “Select a State” data field, and clicked “Go.” Data viewed 10/31/2016 at http://inciweb.nwcg.gov.

Missouri Department of Conservation. Wildfire Data Search. Data downloaded 10/31/2016 from http://mdc7.mdc.mo.gov/applications/FireReporting/Report.aspx.

National Interagency Fire Center. Statistics > Historical Year-End Fire Statistics by State. Data downloaded 10/31/2016 from https://www.nifc.gov/fireInfo/fireInfo_statistics.html.

Wildfires Growing in Size, Not Number


Since 1984, the size of wildfires seems to have grown, though the number of fires does not.


Source: Flathead National Forest.

Figure 1: Source: Flathead National Forest.

In previous posts I have looked at wildfire in the national parks and the role it has in promoting a healthy forest ecosystem. How is wildfire changing over time? Is it increasing? I can address that question two ways: with maps and with statistics. Maps first.

Figure 1 is the top half of a map that shows the history of wildfires in Glacier National Park and the surrounding area from 1984-2015. On the map, the park is shown in pale yellow. Flathead National Forest is shown in pale green. The line at the top represents the border with Canada. The fires are mapped, and the year they occurred is color coded. Bright red represents fires that occurred in 2015, orange represents fires that occurred in 2003, and dark green those that occurred in 2001. In the previous post, I gave you photos of forest recovery in 3 of these fire areas: the Reynolds Creek Fire, the Red Eagle Fire, and the Moose Fire.

Looking at the map, you can see that over the last 22 years, a significant fraction of the area has burned in one fire or another. Orange is the color most represented on the map, and 2003 was, indeed, a very active fire year in this region.

(Click on graphic for larger view.)

Source: Yellowstone National Park.

Figure 2: Source: Yellowstone National Park.

Figure 2 shows the fire history of Yellowstone National Park from 1988-2013. The park is outlined with a black line. As in the previous figure, fires are colored according to the year in which they occurred. If you recall, 1988 was the year of the terrible fires in Yellowstone. Those fires are shown in pale yellow. Approximately 1/3 of the park burned that year. (The map shows the final fire boundaries – not every acre within the boundary burned. Wildfire is very fickle regarding what it burns and doesn’t burn.) Since 1988, fires have been much smaller, and have consumed much less acreage.

What I want you to take away from these maps is that fire is anything but rare in these national parks. It is a yearly occurrence. Over time, significant portions of the park burn – in Yellowstone most of the park has burned in the last 28 years. This is a natural pattern, and evidence from burn scars and layers of ash in the soil suggest it has been this way for thousands of years.

Fire experts estimate that healthy lodgepole pine forests burn about every 90 years on average. Now, that’s an average, so it means that some areas burn more frequently, and some less. About 2/3 of western fires are started by lightening, and nobody knows where lightning will strike.

Total number of reported wildfires in USA. Source: National Interagency Fire Center.

Figure 3: Data source: National Interagency Fire Center.

Tens of thousands of wildfires are reported every year. Figure 3 shows the number of wildfires reported in the USA from 1960-2015. These statistics are compiled by the National Interagency Fire Center from situation reports on individual fires that come in from many sources. Situation reports have been in use for several decades. Prior to 1983 the source of the data is not known, and the data for 1983 and 1984 seem to have been affected by the phasing in of situation reports. Thus, data up to 1984 should not be compared to data after 1984.

Because of variability in the data, I have dropped a 5-year moving average on it for the period after 1984. The trend in the data is not strong, however it may be toward a slightly decreasing number of fires. The years from 2010-2015 all saw a below average number of fires, although in some cases barely.

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Source: National Interagency Fire Center.

Figure 4: Data source: National Interagency Fire Center.

Figure 4 shows the total number of acres burned by wildfire each year. As in Figure 3, data before and after 1984 should not be compared. That said, this data is less ambiguous: there has been an increase in the number of acres burned in both active and inactive fire years.

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Data source: National Interagency Fire Center.

Figure 5: Data source: National Interagency Fire Center.

Figure 5 shows the annual number of acres burned per fire – it is just a graph of the number of acres divided by the number of fires. Again, don’t compare data from before and after 1984 . The first thing I notice is how small the average number of acres is – somewhere between 15 and 150. Given the results of the two previous charts, it is inevitable that the number of acres burned per fire has increased in recent years, and the chart confirms the change. The size of the change is astounding, however. The number of acres per fire in 2012 and 2015 is about double the highest number in the 10 years after 1984.

The data seem clear: the number of fires each year has not increased, but the number of acres burned per fire has, leading to an increase in total acres burned. This goes along with the statement from the U.S. Forest Service that I quoted in the lead post of this series: the size and ferocity of fires has increased in recent years.

I will try to bring the data home to Missouri in the next post.

Sources:

Flathead National Forest. 2015. Current Fires and Fire History 1984-2015: Flathead National Forest & Clacier National Park. August 21, 2015. Downloaded 10/3/16 from http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprd3851454.pdf.

National Interagency Fire Center. 2016. Total Wildland Fires and Acres. Data downloaded 10/3/2016 from https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html.

Yellowstone National Park. 2014. Yellowstone Fires: 1988-2013. Downloaded 10/3/16 from https://www.nps.gov/yell/learn/nature/upload/Fires_88_2013.pdf.

Smokers, Smolders, and Big Blowups


Most wildfires smoke or smolder and don’t amount to much. But some blowup, and then they are dangerous and destructive.


When we think of wildfire, we tend to imagine a raging crown fire, like the one in Figure 1, repeated from the last post. Such fires make for dramatic photos and stories in the media. But raging crown fires are not typical. Lightning ignites hundreds of wildfires every summer, and most go out naturally after burning less than half an acre. Others consume isolated or small groups of trees and eventually go out on their own. In Yellowstone National Park, 72% of fires consume less than 0.2 acres, and 84% consume less than 10 acres. Figure 2 shows the Buffalo Fire burning in Yellowstone National Park on 9/3/2016 – a far cry from the huge wall of fire that threatened Old Faithful in 1988!

Crown Fire Approaching Old Faithful Photo Shop & Snow Lodge. Photo: Yellowstone National Park, photographer unknown.

Figure 1. Crown Fire Approaching Old Faithful Photo Shop & Snow Lodge. Photo: Yellowstone National Park, photographer unknown.

The Buffalo Fire in Yellowstone National Park on 9/3/16. Photo: John May.

Figure 2. The Buffalo Fire in Yellowstone National Park on 9/3/16. Photo: John May.

 

 

 

 

 

 

 

 

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Mature stands of lodgepole pine are dark and dense. No seedlings can sprout, and no understory plants can survive. Downed wood accumulates, and the forest slowly rots. Photo: John May.

Figure 3. Mature stands of lodgepole pine are dark and dense. No seedlings can sprout, and few understory plants can survive. Downed wood accumulates on the forest floor. Photo: John May.

Figure 3 shows the forest floor along the Avalanche Lake Trail in Glacier National Park. An old forest can get positively junky as downed wood accumulates on the forest floor. Fire won’t typically jump too far from log-to-log, it more easily spreads to something nearby. The more downed wood, the better the fire spreads.

Similarly, fire doesn’t like to burn in wet wood – anybody who has ever tried starting a fire with wet wood knows what I mean. In the national parks, fires only burn vigorously if fuel moisture levels drop to 13%. How dry is 13%? Well, kiln-dried lumber, like you buy at the lumber yard, is 12%, so, it is pretty dry. In an average year, the moisture content of downed wood in the national parks is 14-18%, too moist to burn ferociously. In really dry years, however, it can get as low as 5%, and then watch out!

Finally, as anybody who has ever tried to start a campfire knows, moving air makes a big difference. If you have a fire started, what do you do to make it grow? You blow on it. Same in the national parks. A raging fire requires wind.

Thus, three factors have to come together to make a raging crown fire: lots of downed fuel so the fire can spread easily, dry conditions so the wood burns readily, and strong winds to whip the fire into an inferno. Only when those three conditions come together does fire behavior become “extreme,” as they say. When these conditions do come together, however, wildfire becomes extremely dangerous, capable of moving fast, even of hurling fireballs up to a mile away. In 1988, Yellowstone experienced the worst wildfire season in its history. The fire started on June 14. By early August, 8 fires were burning. During the 2 weeks from 8/6 to 8/19, the fires in Yellowstone consumed an average of 11,607 acres per day. Now, that’s already pretty active fire behavior. But on 8/20, the fire exploded, consuming 152,959 acres – 13 times as much. And that wasn’t the worst of it. On 9/9 the fire ate 228,137 acres – in a single day!

So, most wildfires are small and go out on their own. But some blow up, and when they do, they become destructive and dangerous.

The worst fire blowup in United States history may have occurred in 1910 (The Big Blowup). Over 2 days in August that year, fire in Washington, Idaho, and Montana consumed 3 million acres and killed 87 people. The U.S. Forest Service was just 5 years old, and that experience was very influential in the development of the ethos that every wildfire must be suppressed as quickly and vigorously as possible, without exception. We know more nowadays, and the ethos has changed, but it held sway for a long time.

One final characteristic must be mentioned here: how you view a fire depends on where it is burning. A fire in your barbecue is one thing, a fire in your bedroom another. The American landscape is a patchwork of different kinds of land. Some is private, but even public lands belong to a variety of agencies: the National Park Service, the U.S. Forest Service, the Bureau of Land Management, state parks, state forests, wildlife refuges, etc. Differing policies regarding wildfire apply in each of these kinds of land.

Generally, the first, overriding policy is to protect life, whether it be that of firefighters or civilians. The second overriding policy is to protect significant assets, such as homes, mine buildings, ranch buildings, and visitor facilities. After that, the policies vary. In the national parks, fire is thought to be an important part of the ecosystem that is necessary for the health of the forest (more on this in the next post). In the national parks, fire is allowed to fulfill its natural role in the ecosystem without interference, unless it is threatening life or significant assets. The national forests, however, harvest their trees. Thus, the trees are themselves an important asset, and wildfire is much less likely to be allowed to burn without a suppression effort of some sort.

In the next post I’ll look at the role that wildfire plays in renewing the forest, and why it is an important part of the natural ecosystem. I had the chance to see this right before my eyes, and it was pretty impressive.

Sources:

Rothermel, Richard, Roberta Hartford, and Carolyn Chase. 1994. Fire Growth Maps for the 1988 Greater Yellowstone Area Fires. General Technical Report INT-304. Intermountain Research Station, U.S. Forest Service. Downloaded 9/30/2016 from http://www.fs.fed.us/rm/pubs_int/int_gtr304.pdf.

Forest History Society. 2016. U.S. Forest Service Fire Suppression. Downloaded 9/30/2016 from http://www.foresthistory.org/ASPNET/Policy/Fire/Suppression/Suppression.aspx.

Yellowstone National Park. 2008. The Yellowstone Fires of 1988. Downloaded online 9/30/2016 from https://www.nps.gov/yell/learn/nature/upload/firesupplement.pdf.

Yellowstone National Park. 2016. Yellowstone Resources and Issues Handbook. National Park Service. Downloaded 9/28/2016 from https://www.nps.gov/yell/learn/resources-and-issues.htm.

Wildfire!

 


On my vacation, I encountered wildfire in 3 national parks. What does it mean?


In September I returned from a road trip that took me to Glacier National Park, Yellowstone National Park, and Grand Teton National Park. The day I drove to Glacier, my route led through Billings, MT. As I drove in, I found it laying under a thick brown haze, with visibility only about 1 mile, perhaps even less. It made my eyes burn. As I drove out of town, the haze gradually thinned, and disappeared. “What is going on?” I wondered. “This is worse than the air pollution in Los Angeles. Does Billings really have worse air quality than L.A.?”

As I drove north, I encountered another cloud of heavy, brown haze, this one over lightly populated land near Lake Frances. “This can’t be air pollution,” I thought. “It must be smoke from a wildfire somewhere.” And, indeed, it was.

I encountered wildfire and/or its effects in all three national parks. Figures 1, 2, and 3 show smoke near Gardiner, hanging in front of Mt. Moran, and filling the Yellowstone River Valley.

Smoke Obscures the Mountains Near Gardiner, WY, 8/31/16. Photo by John May.

Figure 1. Smoke Obscures the Mountains Near Gardiner, MT, 8/31/16. Photo by John May.

Smoke Obscures Mt. Moran, 9/12/16. Photo by John May.

Figure 2. Smoke Obscures Mt. Moran, 9/12/16. Photo by John May.

Smoke Hangs in the Yellowstone River Valley,9/3/16. Photo by John May.

Figure 3. Smoke Hangs in the Yellowstone River Valley, 9/3/16. Photo by John May.

I asked a ranger, and found out about Inciweb, the interagency system for information about many kinds of risk, especially wildfire. I discovered that 8 wildfires were burning in regions of Montana and Idaho just upwind from Glacier National Park, that 5 were burning in Yellowstone National Park itself, and that one was burning in Grand Teton National Park. This last one, the Berry Fire, twice burned across the highway between Yellowstone and Grand Teton, forcing its closure. Fortunately, I was able to sneak through during the brief period between the two closures. I also discovered that none of these were the worst wildfires of the season; those were burning in California.

Crown Fire Approaching Old Faithful Photo Shop & Snow Lodge. Photo: Yellowstone National Park, photographer unknown.

Figure 4. Crown Fire Approaching Old Faithful Photo Shop & Snow Lodge. Photo: Yellowstone National Park, photographer unknown.

Wildfire sometimes makes for dramatic news stories with spectacular photographs. Perhaps many readers can recall the wildfires in Yellowstone National Park that made national headlines in 1988 (See Figure 4). Yellowstone was devastated, they said, it would never recover.

Guess again, smoke breath! Raging crown fires like the one in the photo are the exception. Most wildfires present a much more complex story. All three of these national parks have been heavily affected by wildfires, but they are far from dead. In fact, in some ways, they are more healthy now than before the fires. On the other hand, a Forest Service publication notes that in the last 25 years, wildfires have increased in size and ferocity. What’s going on?

In the following posts, I hope to share with you the role that wildfire plays in a forest ecosystem, look at whether wildfires are getting larger, more fierce, or more frequent, and how wildfire has impacted Missouri. I found it a fascinating topic to explore, and the evidence was right in front of me. Hopefully I can share it with you in a way that will interest you, too.

Sources:

Forest History Society. 2016. “U.S. Forest Service Fire Suppression.” Downloaded 9/30/2016 from http://www.foresthistory.org/ASPNET/Policy/Fire/Suppression/Suppression.aspx.

Photo of fire approaching Old Faithful Photo: “13744.jpg.” Unknown photographer. Wildfire, 1988 – Crown Fire. Yellowstone’s Photo Collection, Yellowstone National Park. Downloaded 9/26/16 from https://www.nps.gov/features/yell/slidefile/fire/wildfire88/crownfire/page-1.htm.

Missouri Riverine GAP Analysis

Missouri is home to more species than almost any other state in the union. Our fragmented and highly varied topography has led to many, many small, isolated areas in which evolution occurred along slightly different paths, leading to small communities of unique species. How well are we doing at protecting this biodiversity?

One way to assess how well we are protecting our biodiversity is through a gap analysis. The National Gap Analysis Program of the United States Geological Service (USGS) is intended to improve conservation practices by using the following process: first construct a map detailing land cover. Second, construct a map showing the distribution of animal and plant species. Third, construct a map showing the location and conservation status of protected areas. Fourth, use this data to identify gaps where target ecosystems and species are inadequately covered by conservation efforts. It sounds simple, but the process of doing it is quite complex.

Figure 1: Missouri Ecological Drainage Systems and Aquatic Ecological System Types. Source: Sowa (2005).

Figure 1: Missouri Ecological Drainage Systems and Aquatic Ecological System Types. Source: Sowa (2005).

Gap analyses are sometimes made separately for types of ecosystems. A Gap Analysis for Riverine Ecosystems of Missouri was published in 2005 by the USGS (Sowa, 2005). It constructs a gap analysis for Missouri’s streams. The authors constructed an 8-level classification hierarchy that could be used to map Missouri’s streams across the dimensions above (land cover, distribution of species, location and status of protected areas). I’m not going to explain all of the details here, but I do want to illustrate how their analysis proceeded.

Missouri is generally divided into three great hydrologic subregions. In the bootheel is the Mississippi Alluvial Basin. The Central Plains region lies north of the Missouri River and also wraps southward along the border with Kansas. In between is the Ozarks Region. If you have travelled in these regions, perhaps it was obvious to you that the streams in each one are quite different in character from those in the others.

The authors divided these three regions into Ecological Drainage Units. There were 19, and they are shown in Figure 1, delineated by the heavy black lines. These were further divided into 39 Aquatic Ecological System Types (AES-Types). Each AES-Type represented one or more drainage areas containing a small or medium, river with a unique combination of physical habitat, water chemistry, energy sources, hydrologic regime, and community of plants and animals. In Figure 1, the grey lines delineate the AES drainage areas, and the color codes for the AES-Type. AES-Types don’t have to be contiguous, they can be physically separated so long as they contain the same characteristics.

Figure 2: Missouri Valley Segment Types. Source: Sowa 2005.

Figure 2: Missouri Valley Segment Types. Source: Sowa 2005.

The authors then divided the AES drainage areas into even smaller units called Valley Segment Types (VSTs). VSTs were small reaches of streams that had similar characteristics. They identified over 100 different VSTs, and assigned them to literally thousands of small stream segments throughout the state (Figure 2).

The hypothesis of the analysis was that in coarser grained analyses, AES-Type would determine the species of plants and animals found within it, and that VST would play the same role in a finer-grained analysis.

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These analyses were then combined with management information about each stream segment. This primarily represented factors that either harmed or endangered the ecological diversity of the stream segment, like human encroachment, agriculture, and mining, or factors that protected the diversity of stream segments, like inclusion in a national forest, state park, or conservation area.

Figure 3: Human Stress Index. Source: Sowa 2005.

Figure 3: Human Stress Index. Source: Sowa 2005.

The authors represented the degree to which human activities impaired stream diversity by constructing a Human Stress Index, and Figure 3 shows the Human Stress Index for each of the AES drainage areas in Missouri. The higher the index, the darker the red, and the higher the degree of human disturbance.

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Figure 4: Percentage of VSTs with Gap Status of 1 or 2. Source: Sowa 2005.

Figure 4: Percentage of VSTs with Gap Status of 1 or 2. Source: Sowa 2005.

The gap analysis used a scale of 1-4 to rate the relative degree to which biodiversity was protected in each AES-Type and VST, with “Status 1” being most protected and “Status 4” being least. Figure 4 shows the percentage of VSTs in each Ecological Drainage Unit that were rated Status 1 or 2. As you can see, most of the EDUs had very low percentages of VSTs rated 1 or 2. Only those deep in the Ozarks had percentages above 26.5%.

Well, it is a very detailed and complex analysis. Trying to summarize the results is a little confusing. But the bottom line is that in the Central Plains Region of the state (the area north of the Missouri River, and then wrapping south along the Kansas border), only 11.4% of the VST’s were rated Status 1 or 2, while in the Mississippi Alluvial Basin 20.9% were, and in the Ozarks Region, 28.3% were. Throughout most of Missouri, the vast majority of land has been sufficiently degraded that it no longer protects Missouri’s biodiversity. (I have many previous posts about Missouri’s biodiversity, invasive species, and protected lands. To find them, look in the “Land” category of posts.)

To some extent, this finding should be expected; one would not expect urban or agricultural land to support the complex biodiversity that undisturbed land does. But the report puts numbers to that impression, and the result is not encouraging.

There is a great deal of additional information in the report, but it is complex and very detailed, and this post is already long enough. Those who have particular interests in biodiversity in Missouri should look up the report.

Sources:

Sowa, S. P., D. D. Diamond, R. Abbitt, G. Annis, T. Gordon, M. E. Morey, G. R. Sorensen, and D. True. 2005. A Gap Analysis for Riverine Ecosystems of Missouri. Final Report, submitted to the USGS National Gap Analysis Program. Downloaded 6/23/2016 from https://morap.missouri.edu/index.php/aquatic-gap-pilot-project.

Wastewater Injection Causes Oklahoma Earthquake Problem

OklahomaEQsBarGraphOklahoma has been the epicenter of a new environmental problem related to modern times: an increase in the number of earthquakes. Usually the state has 0 – 3 earthquakes per year above Magnitude 3.0, with the strongest being a M5.5 in 1952. In 2009, however, the number of M3.0+ earthquakes each year began increasing. In 2013 the Oklahoma Geological Survey registered 2 of them each week, and since then the rate has continued to increase. As of 4/21/15, the current rate was 2.5 per day! The trend is shown in the chart at right.

Then, in 2011, a Magnitude 5.6 earthquake struck east of Oklahoma City. That’s big enough to cause damage.

According to the Oklahoma Geological Survey, it is

very likely that the majority of recent earthquakes, particularly those in central and north-central Oklahoma, are triggered by the injection of produced water in disposal wells.

The primary suspected source of triggered seismicity is not from hydraulic fracturing, but from the injection/disposal of water associated with oil and gas production. Produced water is naturally occurring water within the Earth that is often high in salinity and co- exists with oil and gas in the subsurface. As the oil and gas is extracted/produced, so is the water. This water is then separated from the oil and gas and re-injected into disposal wells, often at greater depth from which it was produced. (OGS, 4/21/15)

Be sure to catch the distinction here: the problem they identify is not the fracking itself, but rather the water that comes out as the oil and gas are extracted. That water is contaminated, and they dispose of it by injecting it into disposal wells at high pressure. These wells are the suspected culprits.

Earthquake locations. Red = 2014, Green = 2013, Blue = 2012 and previous. Source: Peterson, et al, 2015, Figure 3A.

Earthquake locations. Red = 2014, Green = 2013, Blue = 2012 and previous. Source: Peterson, et al, 2015, Figure 3A.

The area of increased seismic activity stretches from central Oklahoma north into Kansas. It is not the only area experiencing such increased activity. A recent U.S. Geological Survey report identifies 17 areas that have. Five are in Colorado, one in New Mexico, five in Texas, one in Arkansas, one in Mississippi, and two in Ohio. But by far the largest ones are the two involving Oklahoma and Kansas. The map at right shows their locations.

To understand the map, a little background is needed. The USGS studies earthquakes primarily to understand earthquake risk. Their knowledge is used by building officials to determine how earthquake-proof buildings in a given region need to be, and by the insurance industry to understand risk. Earthquakes tend to come in clusters; when there is an earthquake, it results in aftershocks, and sometimes it sets off additional earthquakes nearby. It does not add much to the understanding of risk to say that once there has been an earthquake, others are likely to follow. Thus, the USGS keeps catalogs of earthquakes in two ways. One way is to list an initial earthquake, its aftershocks and its subsidiary quakes as a single cluster. These catalogs are called nondeclustered. I don’t know why they use this awkward double negative, but the point is to try to identify the risk of when a cluster will occur. The other way is to list all earthquakes as individual, separate events. These catalogs are called declustered.

The map at right combines data from both kinds of databases. The dots represent the epicenters of earthquakes of Magnitude 2.7 or larger. The blue dots represent earthquakes prior to 2012 using a declustered catalog. The green dots represent 2013 earthquakes from a nondeclustered catalog. And the red dots represent 2014 earthquakes from a nondeclustered catalog. In other words, the red and green represent single years, and in those years aftershocks and subsidiary quakes have been grouped as a single cluster with their initial earthquake. The blue dots represent all the years before 2012, and each aftershock and subsidiary quake is counted as a separate event. Obviously, the recent outbreak of earthquakes has been quite severe. The majority of these earthquakes have been small or moderate. However, there has been a trend towards increased magnitude, and a few of them have been sufficiently large to cause some property damage.

The kind of waste injection well identified as the culprit in the Oklahoma earthquake swam is permitted in Missouri, but it does not appear to be common. Missouri has little oil and gas extraction compared to some other states. We have not been identified as one of the regions experiencing a swarm of human-induced earthquakes. Our earthquakes center around the New Madrid Fault, a known area of seismic activity.

Sources:

Oklahoma Geological Survey. 4/21/2015. Statement on Oklahoma Seismicity. http://wichita.ogs.ou.edu/documents/OGS_Statement-Earthquakes-4-21-15.pdf.

U.S. Geological Survey. 2015. Earthquakes in Oklahoma of M3+. http://earthquake.usgs.gov/earthquakes/states/oklahoma/images/OklahomaEQsBarGraph.png.

U.S. Geological survey. Oklahoma Earthquake History. Web page accessed 4/25/15. http://earthquake.usgs.gov/earthquakes/states/oklahoma/history.php.

Peterson, Mark, Charles Mueller, Morgan Moschetti, Susan Hoover, Justin Rubinstein, Andrea Llenos, Andrew Michael, William Ellsworth, Arthur McGarr, Austin Holland, and John Anderson. 2015. Incorporating Induced Seismicity in the 2014 United States National Seismic Hazard Model – Results of 2014 Workshop and Sensitivity Studies. USGS Open-file Report 2015-1070. http://pubs.usgs.gov/of/2015/1070.