In which month should I map maritime vegetation?

In which month should I map maritime vegetation?

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I'm studying habitat use by Brent Goose in the UK, a species that feeds on maritime vegetation. It's main food types are Zostera sp., Ruppia sp., Ulva / Enteromorpha sp. and Puccinellia sp. I plan to map these vegetation types on an inter-tidal mudflat in North-east England during the summer.

I want to choose a month to map these vegetation types that will allow the most accurate mapping of their distribution of vegetation across the mudflat. I think there are two considerations 1. the month they easiest to identify 2. the month they are most visible.

Which month should I choose?

One way to approach this problem would be to look at herbarium collections of the taxa that you're interested in. Usually, a flowering or fruiting specimen is easiest to identify; but no matter what character is best for your taxon, if you look at the herbarium collections and see that -most of the collections identified to species, or -the especially good-looking collections, or -flowering/fruiting collections, were made in a certain month or season, that could help you to narrow down your time window.

As a bonus, in reviewing herbarium collections, you'll have given yourself a step towards being able to identify the species.

Some herbaria have some collections online; here, for instance, are records and images for online Puccinellia collections at a number of UK herbaria.


The summers are hot and dry with temperatures reaching up to 38°C (100°F).

In the winter, temperatures stay around -1 °C (30°F) and are cool and moist.

In the winter, temperatures stay around 30°F (-1 °C) and are cool and moist.


The shrublands vary greatly but, 200 to 1,000 millimeters of rain per year can be expected.


Aromatic herbs (sage, rosemary, thyme, oregano), shrubs, acacia, chamise, grasses


West coastal regions between 30° and 40° North and South latitude


Plants have adapted to fire caused by the frequent lightning that occurs in the hot, dry summers.

Example: Johannesburg, South Africa

Monthly Temperature and Precipitation from 1970 - 2000

Month Average Monthly Precipitation (mm) Average Monthly Temperature (°C)
January 156 20
February 107 19
March 100 18
April 55 15
May 15 12
June 7 9
July 4 9
August 8 12
September 30 15
October 76 17
November 120 18
December 132 19
Sum Annual Precip. 810


Shrublands include regions such as chaparral, woodland and savanna. Shrublands are the areas that are located in west coastal regions between 30° and 40° North and South latitude. Some of the places would include southern California, Chile, Mexico, areas surrounding the Mediterranean Sea, and southwest parts of Africa and Australia. These regions are usually found surrounding deserts and grasslands.

Shrublands usually get more rain than deserts and grasslands but less than forested areas. Shrublands typically receive between 200 to 1,000 millimeters of rain a year. This rain is unpredictable, varying from month to month. There is a noticeable dry season and wet season.

The shrublands are made up of shrubs or short trees. Many shrubs thrive on steep, rocky slopes. There is usually not enough rain to support tall trees. Shrublands are usually fairly open so grasses and other short plants grow between the shrubs.

In the areas with little rainfall, plants have adapted to drought-like conditions. Many plants have small, needle-like leaves that help to conserve water. Some have leaves with waxy coatings and leaves that reflect the sunlight. Several plants have developed fire-resistant adaptations to survive the frequent fires that occur during the dry season.

Mission: Biomes

Stories, experiments, projects, and data investigations. Download issues for free.

Biological Sciences - Graduate Biology Program

Biology, the study of living things, is an exciting and dynamic field that offers many areas of focus. Graduate studies in the biological sciences provide opportunities to study viruses, bacteria, protists, fungi, plants, and animals, and to investigate the biochemical, physiological, anatomical, behavioral, or ecological processes that make each organism unique. Specific areas of faculty research interests include. parasitology, systematics of insects and plants, vegetation mapping, animal, plant and bacterial physiology, cellular signal transduction, genomics, micro and macro evolution, vertebrate reproduction, animal mating systems, entomology, behavioral ecology, and ecology of aquatic and terrestrial ecosystems.

The Department of Biological Sciences is located in the Life Sciences Building, which houses facilities including teaching and research laboratories, a core microscopy center, and a modern molecular biology center. Students also have access to the nearby Warner Herbarium, Sam Houston State Vertebrate Museum, Texas Bird Sound Library, an animal rearing facility, and greenhouse. The Department also operates the Pineywoods Environmental Research Laboratory (PERL), a 250 acre field station within five miles of campus that is dedicated to research and teaching.

The Department of Biological Sciences offers MA and MS degrees in Biology and is a contributing partner to the interdisciplinary MS degree in Forensic Science along with the College of Criminal Justice and Department of Chemistry. The MS degree in Biology allows for specialization in one of several areas of Biology and is designed for those students planning to pursue careers in research or environmental biology with governmental agencies and industry. The MS degree in Biology is also appropriate for students planning to continue their training in PhD programs at other institutions or in professional schools. The MS degree in Forensic Science is a degree that prepares the student to work for or consult with various agencies in the criminal justice system.

The MA degree in Biology is primarily designed for secondary education teachers who wish to increase their competency in the field of biology. This degree is not recommended for students who plan to pursue doctoral studies. Students pursuing the Master of Education degree may specialize in Biology as a teaching field.


Competitive teaching and research assistantships are available to graduate students in Biology through the Department of Biological Sciences and individual faculty members, respectively. Teaching assistantships pay a stipend of $14,301 over nine months each year for at least two years. To apply for a teaching assistantship, a TA Application should be completed and sent to Graduate Program Coordinator, Department of Biological Sciences, 2000 Avenue I, Box 2116, Huntsville, TX 77341-2116. The deadline for TA applications is April 15 for admission in the fall and December 1 for admission in the spring. University scholarships are also available. The department also offers competitive research grants to support research activities and travel to scientific meetings. For additional support opportunities, see the College of Science and Engineering Technology scholarship page here.

Admission Requirements

Students seeking admission to the graduate program in the Biological Sciences must submit the Graduate Studies Application for Admission with the one-time application fee to the Office of Graduate Studies, official transcripts of all college-level work (including the transcript that shows the date the undergraduate degree was conferred), official GRE scores, and a statement of purpose. Two letters of recommendation from faculty in the undergraduate major field of study at the student&rsquos undergraduate degree-granting institution are required with the application for admission.

To be granted regular admission to the graduate program, applicants must have an undergraduate degree in biology or a related field. Applicants having an undergraduate degree in a discipline other than biology must successfully complete the equivalent of an undergraduate minor in the biological sciences before being considered for regular admission. For regular admission to the graduate program, applicants must also have a GRE score and undergraduate GPA in concordance with the following formula: <[( 200*GPA) Averaged % ranking] > 300 ]>. For a final admissions decision, GRE scores and undergraduate GPA do not constitute the primary criteria to end consideration of an applicant. Applicants with combined scores of slightly less than 300 using the above formula may be considered for probationary admission.

Master of Arts, 36 Semester Hours with a Minor, 30 Semester Hours without a Minor.

This degree program is well suited for many training objectives, but it is most often recommended for secondary teachers who wish to prepare in two fields. A student may opt to include a minor. This plan requires 32 semester hours (36 with a minor field) of graduate credit. If opting for the MA with a minor, 24 hours are taken in Biology, including BIO 5301 and BIO 5302, and 12 semester hours of graduate credit are required in a minor field that logically supports the major. Completion of a literature-based review paper is required.

Master of Science, 30 Semester Hours with Thesis.

This degree program is designed for those students who select all of their courses from those offered in the Biology program unless otherwise authorized by the Graduate Advisor and the faculty research advisor. Students with this degree are prepared for positions as professional biologists in the public or private sector, teaching at the college level or to begin doctoral programs in the biological sciences. This is a research-oriented degree requiring a thesis. This plan requires 32 semester hours of graduate credit, at least 26 of which must be in courses numbered 5000 or above. Six hours of thesis (3 hours each of BIO 6398 and BIO 6099) and BIO 5301, BIO 5302 (6 hours) are counted toward this 30-hour degree program.

Master of Science, 36 Semester Hours with a Minor and a Thesis.

Students with this degree are prepared for positions as professional biologists in the public or private sector, teaching at the college level or to begin doctoral programs in the biological sciences. This is a research-oriented degree requiring a thesis. This plan requires 36 semester hours of graduate credit. Included in the 36 hours are BIO 5301 and BIO 5302 (6 hours), BIO 6398 and BIO 6099 (minimum 6 hours of thesis), 18 hours of Biology courses and a minor of 12 hours in a field that supports the major. The minor must be approved by the minor-granting program.

Master of Education in Secondary Education.

This degree plan is designed primarily for the secondary teacher. All such degrees originate in the College of Education in the Department of Curriculum and Instruction and require the completion of a minimum of 36 hours of graduate credit, 30 of which must be in courses numbered 5000 or above. Twelve to 24 hours of professional education course work are required (12 hours minimum for minor and 6 hours minimum for a second minor). A comprehensive examination is required. Students may elect from 12 to 24 semester hours in biology in this 36-semester-hour program. A thesis is not required. Course requirements are adjusted to meet individual student needs by the M.Ed. program and the Graduate Advisor for Biology.


In order to receive the MA or MS degree, all graduate students are required to pass a comprehensive examination based on their course work and general biological concepts. The nature of this examination, which may be written and/or oral, will be determined by the faculty. Students must be enrolled the semester they take the comprehensive examination. For MA degrees, a literature-based review paper is prepared in consultation with the student's faculty advisor. Students must defend the literature-based review before the student's advisory committee, and present it to the faculty in seminar format. For MS degrees, students complete a thesis research project under supervision of the student's thesis advisor, and present the thesis to the faculty in seminar format. The thesis must also be defended before the student's thesis committee. Once enrolled in BIO 6099, a student must be continually enrolled until graduation.

Steps to Successfully Improving your Vegetative Buffer to Protect the Salt Marsh

1. Before Planting

Due to regulations in place to protect the salt marsh, understanding local, state or federal authority is a first and necessary step. The South Carolina Department of Health and Environmental Control-Office of Ocean and Coastal Resource Management (SC DHEC-OCRM) has direct permitting authority over “critical areas,” defined as coastal waters, tidelands, beaches and dune systems. Any land disturbance planned within the critical area may require a permit from SC DHEC-OCRM, in addition to any necessary authorizations from the local and federal governments. In most cases, establishing a vegetative buffer occurs on the adjacent upland and does not require disturbance in the salt marsh defined as a critical area therefore, a special permit may not be necessary. For the purpose of this factsheet, the recommended buffer establishment and maintenance actions take place in the upland area above the high water mark, thus inland from the critical area.

Trees and shrubs may be shaped and “limbed up” to frame a view rather than blocking it. Silhouettes of branches and moss can make the salt marsh viewscape even more dramatic and aesthetically pleasing.

Before planting, consider the existing topography, vegetation, and soil present at the site. Whenever possible, use the natural contours and keep existing vegetation in place. The underground structure of existing plants helps to prevent erosion by holding soil in place with their fibrous roots system. Avoid unnecessary erosion by minimizing disturbance to the soil when planting or grading the shoreline bank. As with any new planting, having your soil tested will take the guesswork out of the pH and fertility of the site. See HGIC-1652 Soil Testing.

2. Right Plant, Right Place

Using the “right plant” will increase the effectiveness and chances that the vegetative buffer will survive. Plant selection is narrowed by the dynamic conditions that exist adjacent to a salt marsh, including the ever-present elements of wind, salt, and exposure. There are few appropriate plants for such sites, and most of these will be the native plants that have adapted to the pressures of living near the salt marsh. Once established, native plants typically require less maintenance time and cost, while also supporting local wildlife such as birds and beneficial insects including butterflies and other pollinators.

3. Maintaining Your Vegetative Buffer Adjacent to the Salt Marsh

Maintaining your vegetative buffer is important in ensuring the continued success, function and aesthetic appeal of the buffer zone. For the purpose of this factsheet, the following recommended actions occur in the “buffer maintenance zone,” described as the area up to 50 feet inland from the critical area. Additional local buffer requirements may apply.

    • Turf grass in the buffer zone: If turf grass exists within your buffer maintenance zone, the lawn should be kept at the maximum recommended height for the specific turf, which will allow for a more extensive root system, help stabilize soil, and afford a larger leaf area, which can work to slow runoff, and capture sediment. See HGIC-1205 Mowing Lawns.
    • Irrigation considerations: Irrigating within the buffer maintenance zone should be minimized to ensure that excess fresh water does not run off into salt marsh or tidal creeks. Stormwater occurs through irrigation efforts as well as rainfall events and can transport harmful pollutants to area waterways.
    • Chemical controls: Consistent with management recommendations for areas adjacent to freshwater shorelines, pesticides and fertilizers should be avoided in the buffer maintenance zone. Weed control is best done by hand pulling. Mulch can help to unify the landscaped area and will also protect plants by conserving soil moisture and moderating temperature however, mulch should only be spread in the upper portions of the buffer area to avoid being carried away during high tides. To reduce the potential for weed growth in the buffer area, consider spacing plants closely together.
    • Maintenance: Any cut or mowed plant material within the buffer maintenance zone should be removed so that excess plant material does not wash away, potentially leading to water quality issues and water navigation challenges.

    What Should I Plant in My Food Plot?

    One of the most common questions we get on social media and through our website goes something like this: “I have X acres where I hunt to plant a food plot. What should I plant?” And while I wish there was one “magic bullet” food plot mix we could share that would provide deer with year-round nutrition and suit every deer hunter’s needs, it simply doesn’t exist. There are lots of variables that go into choosing the right food plot mix for any given location and situation, including the amount of sunlight and moisture the site receives, the region’s temperature range, soil type and fertility, and even the goals of the would-be food plotter.

    So, while I can’t supply you with a magic food plot mix, I can lay out several options for various scenarios that will hopefully get you started in the right direction and provide you with the resources to figure out exactly what mixes are best suited for your particular situation.

    Food plot plantings fall into one of two categories — warm-season or cool-season. Warm-season plantings are typically planted in spring and grow throughout the summer and into fall. These include forages such as soybeans, corn, grain sorghum, lab lab, and cowpeas.

    Cool-season forages, on the other hand, are planted in the fall or early spring and depending on the species, can grow throughout the year. This includes forages such as wheat, cereal rye, oats, clovers, chicory and brassicas.

    Warm-season forages are typically annuals, while cool-season forages can be either annuals or perennials. Annuals, by definition, germinate, grow, mature and die back in a single growing season. The benefit is the plant germinates and grows quickly, providing attraction in a relatively short period of time. Examples of cool-season annuals are wheat, oats, rye (cereal rye, not ryegrass), and brassicas. Perennials on the other hand, are typically slower to establish, but they re-grow from their root systems for two or more years, meaning you don’t usually have to replant the food plot every year. Cool-season perennials include most clovers and chicory.

    The purpose of your plot or plots will help guide you in determining which species to plant. If you are looking for an early season kill plot, or to provide nutrition while bucks are actively growing antlers and does are lactating, then a warm-season forage or mix will be your best bet. If you want a kill plot for later in the season, or to provide excellent forage during the nutritionally stressful winter and early spring, then a cool-season plot may serve you better. If, however, you want the best of both worlds and the opportunity to provide year-round nutrition to the deer herd, then it’s a good idea to plant some of each.

    With hundreds of seed mix options available these days, there is no way I could cover even a fraction of them in one post, so I’ve laid out a few that should cover most scenarios for both northern and southern white-tailed deer hunters. Most of the mixes listed below are commercially available from seed vendors such as Mossy Oak Biologic, Tecomate and Whitetail Institute. Buying premixed can be beneficial for those planting small plots where it doesn’t make sense to purchase individual bags of seed to mix yourself. Just be sure to check the label before purchasing a commercial seed mix to make sure the species included are suitable for your area and will cover the acreage to be planted.

    Note: Regardless of what you decide to plant, take the time to pick up some soil sample bags from your local extension office and get a soil sample from each potential food plot location. Once you’ve received the results from those tests, lime and fertilize accordingly. The cost of the test is minimal and skipping this step could result in food plot failure.

    Two Cool-Season Mix Options

    Southern Cool-Season Mix

    Wheat or oats 40 lbs./acre
    Crimson clover 15 lbs./acre
    Arrowleaf clover 5 lbs./acre

    Northern Cool-Season Mix

    Wheat 40 lbs./acre
    Austrian winter peas 20 lbs./acre
    Forage brassica 4 lbs./acre

    Read more about these mixes in a previous article on cool-season food plot mixes.


    Many animals, particularly those living in arid environments where solar facilities are more common, are living at their physiological limits any added movement may thus be costly (Vale & Brito, 2015 ). Whether and how movements are influenced by a solar facility will be determined by: (a) the trade-off of associated benefits and costs, (b) whether species are attracted or deterred by solar facilities, (c) whether a species is residential or migratory, and (d) the fitness impact of the responses.

    3.1 Resident species

    Solar facility construction and operation directly and indirectly alter habitat use via functional habitat fragmentation, dispersal limitations, population isolation, and altered habitat quality (as previously reviewed in Lovich and Ennen ( 2011 )). For example, vegetation at road edges appears to attract Agassiz's desert tortoises (Gopherus agassizii) to build burrows there, despite the apparent noise pollution and risk of vehicle collision (Lovich & Daniels, 2000 von Seckendorff Hoff & Marlow, 2002 ). CSP facilities can include evaporation ponds with chemically treated waters these polluted waters can kill via drowning, poisoning, egg mortality, or biomagnification (Jeal, Perold, Ralston-Paton, & Ryan, 2019 ). Electromagnetic fields created by buried and aerial cables transporting energy can affect orientation of some organisms, impairing habitat use and likely causing additional physiological harm (Lovich & Ennen, 2011 Shepherd et al., 2019 Wyszkowska, Shepherd, Sharkh, Jackson, & Newland, 2016 ). Also, changes in albedo from vegetation removal could cause local increases in temperature and evapotranspiration, which may influence movement patterns, reproductive success, and survival (Barron-Gafford et al., 2016 ). Although certain habitat modifications could benefit species, such as birds that can exploit solar facility structures for foraging, roosting or nesting (Jeal, Perold, Ralston-Paton, & Ryan, 2019 ) or prey species that experience reduced predation (Cypher et al., 2019 ), in most cases, modifications are likely to have negative impacts.

    3.2 Migratory species

    3.3 Facility siting

    Effects of climate and atmospheric CO 2 partial pressure on the global distribution of C 4 grasses: present, past, and future

    C4 photosynthetic physiologies exhibit fundamentally different responses to temperature and atmospheric CO2 partial pressures (pCO2) compared to the evolutionarily more primitive C3 type. All else being equal, C4 plants tend to be favored over C3 plants in warm humid climates and, conversely, C3 plants tend to be favored over C4 plants in cool climates. Empirical observations supported by a photosynthesis model predict the existence of a climatological crossover temperature above which C4 species have a carbon gain advantage and below which C3 species are favored. Model calculations and analysis of current plant distribution suggest that this pCO2-dependent crossover temperature is approximated by a mean temperature of 22°C for the warmest month at the current pCO2 (35 Pa). In addition to favorable temperatures, C4 plants require sufficient precipitation during the warm growing season. C4 plants which are predominantly graminoids of short stature can be competitively excluded by trees (nearly all C3 plants) - regardless of the photosynthetic superiority of the C4 pathway - in regions otherwise favorable for C4. To construct global maps of the distribution of C4 grasses for current, past and future climate scenarios, we make use of climatological data sets which provide estimates of the mean monthly temperature to classify the globe into areas which should favor C4 photosynthesis during at least 1 month of the year. This area is further screened by excluding areas where precipitation is <25 mm per month during the warm season and by selecting areas classified as grasslands (i.e., excluding areas dominated by woody vegetation) according to a global vegetation map. Using this approach, grasslands of the world are designated as C3, C4, and mixed under current climate and pCO2. Published floristic studies were used to test the accuracy of these predictions in many regions of the world, and agreement with observations was generally good. We then make use of this protocol to examine changes in the global abundance of C4 grasses in the past and the future using plausible estimates for the climates and pCO2. When pCO2 is lowered to pre-industrial levels, C4 grasses expanded their range into large areas now classified as C3 grasslands, especially in North America and Eurasia. During the last glacial maximum (∼18 ka BP) when the climate was cooler and pCO2 was about 20 Pa, our analysis predicts substantial expansion of C4 vegetation - particularly in Asia, despite cooler temperatures. Continued use of fossil fuels is expected to result in double the current pCO2 by sometime in the next century, with some associated climate warming. Our analysis predicts a substantial reduction in the area of C4 grasses under these conditions. These reductions from the past and into the future are based on greater stimulation of C3 photosynthetic efficiency by higher pCO2 than inhibition by higher temperatures. The predictions are testable through large-scale controlled growth studies and analysis of stable isotopes and other data from regions where large changes are predicted to have occurred.

    Keywords: C4 CO2 Climate change Grassland Key words Photosynthesis.

    Comprehensive Nutrient Management Plan (CNMP)

    What is CNMP?

    Animals have been, are, or will be stabled or confined and fed or maintained for a total of 45 days or more in a 12-month period, and

    Where crops, vegetation, forage growth, or post harvest residues are not sustained in the normal growing season over any portion of the lot of facility.


    Plan Development Resources and References (FY2017 and later) any CNMP plans contracted with a producer after September 30, 2016 must be developed in accordance with the following Pennsylvania / CNMP / Conservation Activity Plant 102 Outline & Planning Guidance for FY2017. Plan writers have the option to adapt these new guidelines for prior year contracts.

    Guidance and references applicable to entire CNMP (FY2017 and later)

    The development of a CNMP follows the National Planning Procedures Handbook Title 180-600.

    Technical Service Provider (TSP) CNMP and CAP (102)

    TSP certification in TechReg is required for all TSP's who provide CNMP services through an NRCS Participant Contract or Agreement.

      &ndash Coordination, development and approval of the entire CNMP, including each technical element and producer agreement.
      • Participant funding is provided through state&rsquos Technical Assistance Funds.
      • Participant funding is provided through state&rsquos Financial Assistance Program (EQIP). Usual category for TSPs.

      Registered in Pennsylvania Professional Engineer (PE) signature required for Engineering I&E.

      Quality Assurance

      NRCS will review the first CNMP approved by each TSP with CNMP Plan Approval / CNMP Conservation Activity Plan (CAP 102) certification. All CNMPs are subject to annual 5 percent quality assurance review and random spot-checking at any time.

      Simply put, NDVI measures the state and health of crops or crop vigor. This vegetation index is an indicator of greenness and has a strong correlation with green biomass, which is indicative of growth. NDVI values are also known to have a high correlation with crop yield, meaning it can be used as a tool for measuring crop productivity and predicting future yield.

      As a matter of fact, NDVI values obtained with satellite data with high temporal resolution (e.g., MODIS) have a strong correlation with crop phenological stages (emerged, maturity, harvest). However, there are certain limitations. For instance, during the early stages of crop growth, when the green leaf area is small, NDVI results are very sensitive to soil background effects. The NDVI may also saturate at later stages, when the crops reach canopy closure, and produce inaccurate results.

      National Preparedness Month 2020: Landslides and Sinkholes

      Natural hazards have the potential to impact a majority of Americans every year. USGS science provides part of the foundation for emergency preparedness whenever and wherever disaster strikes.

      USGS: Start with Science

      The USGS works with many partners to monitor, assess, and conduct research on a wide range of natural hazards. USGS science provides policymakers, emergency managers, and the public the understanding needed to enhance family and community preparedness, response, and resilience.

      By identifying potential hazards and using USGS hazards science, federal, state, and local agencies can mitigate risk. In addition, USGS science can inform planning for major infrastructure investments and strengthen private property standards and materials, which help make homes and communities more resilient to natural hazards. While everyone should be aware of the hazards that are most prevalent in their community, the annual National Preparedness Month is a great time to learn about all hazards. Two of the lesser-known hazards for most Americans – but which can occur almost anywhere – are landslides and sinkholes.

      Landslides occur in all fifty states and every U.S. territory, and cause the loss of life and billions of dollars in damage to public and private property annually. The USGS Landslide Hazard program (LHP) is dedicated to understanding how and why these events occur and how best to make informed assessments of the hazard to inform communities that may be at risk, ultimately helping to save lives and property, and to support the economic well-being of American communities.

      Diagram of deep-seated landslide, from USGS Fact Sheet 3004–3072, “Landslide Types and Processes.”

      Landslide processes and characteristics, such as size, distance travelled, trigger, and speed can vary tremendously, and these differences make understanding landslide events challenging. USGS scientists work to assess where, when, and how often landslides occur and how fast and far they might travel.

      The following examples of recent landslide research by the USGS LHP show how our scientists provide reliable scientific information to minimize the loss of life, infrastructure, and property.

      United States Landslide Inventory Map – Our understanding of landslide hazards at the national scale is limited because landslide information across the U.S. is incomplete, varies in quality, and is not accessible in a single location. In order to fix these obstacles, USGS scientists produced a website that marks an important step toward mapping areas that could be at higher risk for future landslides. In collaboration with state geological surveys and other Federal agencies, USGS has compiled much of the existing landslide data into a searchable, web-based interactive map called the U.S. Landslide Inventory Map. This database is an important first step to helping assess where, when, and how often landslides occur in the United States.

      Oso Landslide 3D Elevation example screenshot from the USGS 3D Elevation Program (3DEP).

      Barry Arm Landslide, Prince William Sound, Alaska – In May of this year, the Alaska Division of Geological & Geophysical Surveys (ADGGS) alerted nearby communities and businesses about the possibility of a large landslide at the tip of the Barry Glacier in the Prince William Sound of Alaska that could enter the fiord and cause a potentially significant tsunami in the region.

      Annotated photo showing landslide areas of Barry Arm Fjord, Alaska. Subaerial landslides at the head of Barry Arm Fjord in southern Alaska could generate tsunamis (if they rapidly failed into the Fjord) and are therefore a potential threat to people, marine interests, and infrastructure throughout the Prince William Sound region.

      USGS landslide geologists and remote-sensing experts coordinated with the Civil Applications Center and collected radar and optical imagery over the landslide, which revealed less than a few centimeters of landslide movement from late June to August of 2020. To complement these data, ADGGS collected high-resolution light detection and ranging (lidar) data and optical ortho-imagery (or imagery collected by remote sensors and then enhanced with geometric methods) of the landslide to get a more comprehensive picture of what is taking place in the area around the glacier. The interagency group continues to regularly meet and release data and information for the public.

      Post-Wildfire Debris-Flow Hazard Assessments: Glenwood Canyon, Colorado – In August of 2020, the Grizzly Creek Fire burned through steep terrain in Glenwood Canyon and closed Interstate 70, which is the main east-west transportation route through Colorado. This is near the location of the deadly 1994 South Canyon Fire and Storm King mountain, where debris flows in September 1994 swept vehicles off the road.

      A “debris flow” is a type of landslide that typically consists of a fast-moving mass of water, rock, soil, vegetation, and even boulders and trees, and can be very hazardous to infrastructure and public safety. USGS investigations into the 1994 event marked the beginning of coordinated efforts to provide what are called “post-fire debris-flow” hazard assessments. Emphasis on this specific type of landslide was the result of realizing that after a fire, certain conditions including burn severity, vegetation type, slope steepness, soil type, and, most significantly, the amount of post-fire rainfall can contribute to these highly destructive debris flows. Debris flows are one of the most dangerous hazards after a wildfire, and community awareness is critical.

      Grizzly Creek Fire (Colorado) Post-fire Debris-flow Hazard Map displays estimates of the likelihood of debris flow (in %), potential volume of debris flow (in m 3 ), and combined relative debris flow hazard. These predictions are made at the scale of the drainage basin, and at the scale of the individual stream segment. Estimates of probability, volume, and combined hazard are based upon a design storm with a peak 15-minute rainfall intensity of 24 millimeters per hour (mm/h). Predictions may be viewed interactively by clicking on the button at the top right corner of the map displayed above.

      Typically, after a forest fire is contained or nearly contained, the USGS LHP provides rapid assessments of post-fire debris-flow potential and size, in relation to estimates of triggering rainfall. These assessments support Federal, state, and local land and emergency response managers, homeowners, natural resource agencies, and other government agencies in identifying and potentially mitigating post-wildfire debris flows. Landslide hazard mapping and data are posted at the USGS Emergency Assessment of Post-Fire Debris-Flow Hazards website along with more than a dozen additional post-wildfire debris flow assessments for large fires across the country.

      For the Glenwood Canyon Fire, at the request of the U.S. Forest Service, and while the fire was still rapidly growing, the USGS delivered a “pre-fire” debris-flow hazard assessment for all of Glenwood Canyon, including portions that had not burned. USGS scientists collaborated with an interagency Burned Area Emergency Response (BAER) team, including the Natural Resources Conservation Service, USFS, and state agencies to produce these assessments.

      The maps were then used to inform fire operations staff of locations at potential risk for post-wildfire debris flows and to stage fire-fighting equipment and personnel. The USGS will also deliver a final post-fire debris flow assessment after the BAER team finalize their soil burn severity map, which is a key input to the overall hazard model.

      Every year, land subsidence and collapse – or “sinkholes” – causes significant damage to personal property and public infrastructure. By one estimate, the cost of sinkhole damage to the country is several hundred million dollars annually however, sinkhole occurrences are often not reported, and the true cost is likely much higher.

      Photo 14 of 15: Remnants of community pool in sinkhole. View to east across the sinkhole.

      (Credit: Anthony S. Navoy, USGS. Public domain.)

      One of the more famous sinkhole events occurred on February 12 th , 2014. A large sinkhole opened beneath the National Corvette Museum in Bowling Green, Kentucky and damaged or destroyed eight cars. Although the property damage was substantial, the collapse occurred in the early morning while the museum was closed and fortunately no one was hurt.

      A much more tragic event occurred a year earlier. A man in Seffner, Florida, lost his life when a sinkhole opened beneath his house and swallowed him while he was in bed.

      What exactly is a sinkhole, and why do they occur?

      Sinkholes form when the land surface slowly subsides or collapses into pre-existing voids underground – essentially “air pockets” underneath the perceptibly “solid” ground we walk on every day. Such voids are often the result of movement and removal of sediments by water flow, a process known as piping. A sinkhole can occur as a result of natural processes or can be induced by human activities.

      Cover-collapse sinkholes

      Cover-collapse sinkholes may develop abruptly (over a period of hours) and cause catastrophic damages. They occur where the covering sediments contain a significant amount of clay. Over time, surface drainage, erosion, and deposition of sinkhole into a shallower bowl-shaped depression.

      Some minerals, such as salt, limestone, or gypsum, in bedrock can dissolve slowly over time and leave open voids within the rock where groundwater flows. These areas are called karst and have characteristic landforms such as caves, sinking streams, and springs in addition to sinkholes.

      About twenty percent of the nation has the potential to host karst landscapes. In karst areas, the sediments overlying the bedrock are piped down into the bedrock voids and ultimately carried away by moving groundwater. The surface landforms are the result of voids in the bedrock formed by this process over long periods of geologic time, and as those sediments covering the bedrock are removed, subsidence occurs. The USGS produces geologic and subsurface maps that help managers and others to understand karst regions and identify local areas that may be susceptible to sinkholes.

      Where do sinkholes occur?

      Although there is not yet an effective method to predict where an individual sinkhole may occur, the USGS produces geologic maps that help to identify regions that may be susceptible to sinkhole formation. However, sinkholes can occur just about anywhere. It all depends on the subsurface geological composition and the characteristics of the area, i.e., type of unconsolidated and consolidated soils, infrastructure, and void dynamics.

      Map shows karst areas of the continental United States having sinkholes in soluble rocks (carbonates and evaporites), as well as insoluble volcanic rocks that contain sinkholes. The volcanic bedrock areas contain lava tubes that are voids left behind by the subsurface flow of lava, rather than from the dissolution of the bedrock. Hot spots of sinkhole activity are also shown in areas of greater susceptibility. Source: Progress toward a preliminary karst depression density map for the conterminous United States

      What to do if you think you have found a sinkhole?

      It is recommended that people constantly observe their property for signs of “subsidence,” (aka, “sinking”) such as tilted floors, misaligned door frames, or cracking and small holes in and around structural foundations. Water that flows on the surface and sinks into a depression or directly into a hole within the ground surface may indicate a sinkhole. In areas historically susceptible to sinkholes, surface streams can disappear entirely into active sinkholes and may be a concern for groundwater quality. Additionally, information on the locations of areas susceptible to sinkholes can be obtained from county offices, local or state geological surveys, or maps produced by the USGS.

      Excavated sinkhole at a golf course at Top of the Rock Ozarks Heritage Preserve in Missouri that occurred in May of 2015. Photo taken in February of 2018.

      I have (or think I have) a sinkhole on my property. What should I do?

      First, rule out human causes for a possible sinkhole. Some sinkholes are the result of leaky underground pipes (this would be an issue for your utility company), poor drainage control around building foundations, or old construction pits or buried materials that have settled. While the USGS studies the areas that can potentially form natural sinkholes, the agency does not investigate individual sinkholes on private property.

      Cover-collapse sinkhole in limestone near Frederick, Maryland (September 2003). Many sinkholes occur along highways where rainwater runoff is concentrated into storm drains and ditches increasing the rate of sinkhole development (note the sewer drain pipe beneath roadway).

      (Credit: Randall Orndorff, U.S. Geological Survey. Public domain.)

      If you are confident that a possible sinkhole is a result of natural causes, you can:

      • check your homeowner's insurance policy to see if you might be covered (depending upon which state you live in, insurance policies may not cover damage due to natural sinkholes).
      • contact the appropriate utility company if you are concerned about damage to gas, electric, water, or sewer lines.
      • contact your state geological survey. They are the experts in your area’s geology, and they might be able to explain why a sinkhole is forming. Some states have extensive online information about sinkholes, and they often have a mechanism to report them.

      If you do confirm that there is a sinkhole in your area, ultimately a professional geologist or geotechnical engineer should be consulted either by you or state authorities to determine what is happening and how the impacts of a sinkhole might be mitigated.

      More Information on Landslides and Sinkholes