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Kansas School Naturalist


KSN - Vol 10, No 1 - Microclimate

THE COVER PICTURE, showing the portion of Chase County in which Roth's microclimatic observations were made, was supplied by the Chase County Office of the United States Soil Conservation Service, Cottonwood Falls. The Ryan property, in the northeastern portion of which the study habitats were located, is shown by the rectangle outlined in white. Special thanks are due Dr. E. J. Ryan, Emporia physician and nature enthusiast, who has made the 20-acre tract available for this and other ecological research.

Volume 10, Number 1 - October 1963

Microclimate

by John Breukelman, Department of Biology, and
Stanley D. Roth, Jr., Lawrence High School

 

ABOUT THIS ISSUE

Published by The Kansas State Teachers College of Emporia

Prepared and Issued by The Department of Biology, with the cooperation of the Division of Education

Editor: John Breukelman, Department of Biology

Editorial Committee: Ina M. Borman, Robert F. Clarke, Helen M. Douglass, Gilbert A. Leisman, David Parmelee, Carl F. Prophet

Online format by: Terri Weast

The Kansas School Naturalist is sent upon request, free of charge, to Kansas teachers and others interested in nature education. Back numbers are sent free as long as the supply lasts, except Vol. 5, No. 3, Poisonous Snakes of Kansas. Copies of this issue may be obtained for 25 cents each postpaid. Send orders to The Kansas School Naturalist, Department of Biology, Kansas State Teachers College, Emporia, Kansas.

The Kansas School Naturalist is published in October, December, February, and April of each year by The Kansas State Teachers Col­lege, Twelfth Avenue and Commercial Street, Emporia, Kansas. Second-class mail privileges authorized at Emporia, Kansas.


The photographs other than the cover picture were taken by Robert F. Clarke, Assistant Professor of Biology. Figures 1, 2, and 13 are repented from previous issues of The Kansas School Naturalist. All photographs, as well as Figures 14 to 17, were made for use in an unpublished research paper, "The Comparative Microclimate of Four Habitats in Chase County, Kansas," by Stanley D. Roth, Jr., submitted to the Department of Biology as a part of the requirements for the Degree Master of Science.


Climate is sometimes defined as the average condition of the weather, in a geographic region, over a period of years, as shown by such measurements as temperature, humidity, pressure, wind velocity and direction, cloudiness, and precipitation. But climate is much more than the average weather of a region. A statement or description of climate includes the extremes of weather conditions. You do not have a correct picture of the climate in your home town, county, or state unless you know the highest and lowest temperature as well as the average temperature for each season. In Kansas it is especially important to know the largest and smallest amounts of precipitation for various periods, because precipitation is highly variable here. In anyone place, the weather is constantly changing-from hour to hour, from day to day, in day-and-night cycles, through the seasons. Observations extending over many years are necessary for an accurate description of the "normal" conditions which make up the climate.

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Figure 1. Average monthly precipita tion in Kansas for three selected years: in the wet month of June 1951 Kansas received nearly two-thirds as much precipitation as in the whole dry year of 1956.

The book Climate of Kansas published by the Kansas State Board of Agriculture, includes general sections on precipitation, temperatures, frosts, winds, sunshine and cloudiness, relative humidity, and various related topics such as dust storms, aviation weather, thunderstorms, tornadoes, and winter storms. The book contains dozens of charts, maps, and tables giving details by year and month, by county, and in other ways, of the various measurements of temperature, rainfall, and other weather conditions.

The overall picture of Kansas climate, as of the climate of most continental areas, is one of variation. It has been said that "if you don't like the weather in Kansas, just wait a few minutes-it will change." Two samples of this variability are shown in Figures 1 and 2. Figure 1 shows the mean (average ) monthly precipitations for the entire state during three years, one extremely dry, one average, and one extremely wet. Figure 2 shows the variation in temperature and relative humidity as recorded automatically for a six-day period in September 1961.

SIZE OF MlCROCLIMATES

Even the most accurate and complete definition of climate does not limit the size of the region involved. The area may be as large as Kansas or North America, but it may also be as small as a square foot, square inch, or a square millimeter. It may be only a layer of air a yard or a foot thick. Plants and animals living in the same geographic area, and therefore in the same overall climate, may be living in quite different microclimates. Another way of saying this is that organisms living in the same general environment may live in quite different microenvironments. "Microclimate" is the word scientists use for the little climates in the small areas in which plants and animals actually live and to which they must adjust themselves if they are to survive and prosper.

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Figure 2. Variations in temperature mod relative humidity at the Ross Natural History Reservation during a 6-day period in September 1961; no that the relative humidity reached 100 per cent each night.

One author has defined a microclimate as the climate within two meters above the ground. Other investigators, especially those who study the larger plants and forests, treat the microclimate as that within about 100 meters above the ground.

In the garden, an earthworm and a sparrow are not subjected to the same environmental conditions. To a clump of moss growing in a cool spot on the north side of the school house, the climatic conditions on the south side of the building do not matter. The size of the region for which a microclimate is detennined thus depends mainly upon the kinds of organisms studied. The climatic region is relatively large for a bird, small for a mushroom and still smaller for a clump of the alga Protococcus growing on the bark of a tree.

In this issue of The Kansas School Naturalist, we are dealing mainly with climates in small areas, but not areas of any given size. The microclimate is larger for animals that move about than for those that stay in one place. It is a thicker layer for trees than for grasses.

VARIATION OF ENVIRONMENTAL CONDITIONS

A standard weather thermometer, located near the shore of Lake Wooster on the Emporia State campus, on a recent winter day recorded a high of 66 degrees and a low of 18 degrees below zero Fahrenheit. These temperatures were recorded at a level at which weather records are often taken about five feet above the ground. During this 24-hour period when the air temperature according to the standard thermometer varied 84 degrees Fahrenheit, the temperature in the water in the lake stood at 39 degrees Fahrenheit throughout the day and night. To a water animal living under the ice, neither the range of 84 degrees nor the sub-freezing -18 degrees were of any importance.

The fire which sweeps across a dry Flint Hills pasture may raise the above-ground temperature enough to kill all insects and insect eggs living in or on the burning grasses and weeds, but it only slightly warms up the grasshopper eggs deposited safely an inch or so below the surface.

Many other environmental conditions may differ markedly over distances of only a few inches or a few feet, either horizontally or vertically. Above the surface of a flat rock, the moisture content of the air may be at desert level, while four inches down, under the same rock, the relative humidity may be nearly 100 per cent. Across the surface of a close-clipped lawn, the wind velocity may be 20 miles per hour, while three inches down, at the surface of the ground, it may be zero or nearly so. To an organism that lives within the lower half of this three inch layer, the wind is not an important climatic factor.

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Figure 3. The four habitats in which microclimates were studied: Habitat I, rocky, open prairie; Habitat II, tall-grass prairie; Habitat III, rocky-shrubby hillside; Habitat IV. wooded hillside.

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Figure 4. The six thermometers in place in the stake that holds them at the levels indicated

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Figure 5. The soil thermometer used for the determination of ground temperature

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Figure 6. Upper: thermometers in place for observation of temperatures at six levels; lower: recording the temperatures in a field notebook

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Figure 7. The hand-aspirated psychrometer used to record relative humidity; an air current is forced over the wet-bulb and dry-bulb thermometers by pumping the large rubber bulb.

MEASUREMENT OF MICROCLIMATIC CONDITIONS

Official government weather instruments are often located in places where most plants and animals or even people live. The trees and birds live in climates similar to those where most weather measurements are made, but most other living things live near the ground, underground, in water, in buildings made by man, in fallen logs, w1der the bark of trees, and in or on the bodies of other plants and animals. If we want to know much more about the climates in which specific plants and animals live, we must make the measurements where these organisms are found.

While he was a graduate student in the Department of Biology, the junior author of this issue of The Kansas School Naturalist (Roth) studied microclimatic conditions in a typical Kansas area. For the twelve month period from September 1957 to August 1958 inclusive he made semi-monthly trips (except during the winter months when the trips were monthly) to an area in Chase County, Kansas, owned by Dr. E. J. Ryan of Emporia. The period of study was divided into four seasons, each of three months duration. Fall included September, October, and November; winter included December, January, and February; spring included March, April, and May; and summer included June, July, and August.

Four different habitats (Figure 3) were chosen, including a rocky open prairie area (Habitat I ), a tall-grass prairie area (Habitat II) , a rocky-shrubby hillside (Habitat III ), and a wooded hillside (Habitat IV). The microclimate of these four habitats was measured at eight a.m., two p.m. and eight p.m. During each run, temperature was recorded at ground level and at two, six, 12, 20, 30, and 40 centimeters above the ground. Relative humidity was recorded at ground level and at 20, 55, and 200 centimeters above the ground. Wind velocity was recorded at ground level and at 55 and 200 centimeters above the ground. The 200-centimeter observations were made to compare climatic factors near the ground with those at a common "weather bureau" altitude.

Air temperature was recorded with ordinary mercury thermometers placed in holes in a wooden stake, at altitudes of two six, ) 12, 20, 30 and 40 centimeters above the ground, as shown in Figure 4. The stake was set so that the bulbs of the thermometers were in the shade of the stake. The ground temperature was taken with a soil thermometer, placed in the ground so that the thermometer itself was in the shade. Temperatures were recorded in degrees centigrade, and so appear in Figure 15.

Relative humidity was recorded by a Bendix-Friez hand-aspirated psychrometer, based on the wetbulb, dry-bulb principle. Humidities were recorded at ground level and at 20, 55, and 200 centimeters above the ground.

Wind velocity was measured by a Bacharach anemometer. Maximum and minimum readings (in feet per minute) were recorded at ground level, and at 55 and 200 centimeters above the ground. An attempt was made always to face the anemometer into the wind, but this was sometimes difficult because of rapidly shifting winds. The velocity tabulated for each observation (Figures 16 and 17) was the mean between the maximum and the minimum for the period of about one minute.

THE HABITATS STUDIED

Habitat I was a rocky, open prairie area, The substrate was composed primarily of fine gravel mixed with the minimum amount of humus. Small to medium size rocks randomly overlay the area. During the first few months of the study it was intermittently grazed by cattle. During the late spring and summer there was an abundance of vegetation in this habitat,i1 but during the winter it was nearly denuded. This habitat supported the least amount of vegetation of any of the four habitats studied.

Habitat II was a tall-grass prairie area. The specific area is small in size, being approximately ten feet from an area similar to Habitat I and approximately thirty feet from a wooded area. The site had been fenced and kept from livestock for several years. It had been little disturbed in recent years.

Habitat III was a rocky-shrubby hillside area. It was approximately twenty feet from a wooded ravine and adjacent to a tall-grass area. The habitat was characterized by the rocky, gravelly surface of the ground and scattered clumps of grass and shrubby vegetation.

Habitat IV was a wooded hillside are:l. It was characterized by medium sized trees and a moderately heavy ground cover of leaf litter. The habitat was located on a west-facing hillside, marking the east boundary of the valley of the South Fork of the Cottonwood River, well protected by a dense growth of vegetation. This habitat supported the most vegetation of all habitats studied.

Space does not permit showing all of the results, but some typical observations at each habitat are shown in Figures 14 and 17. As might be expected from the lack of abundant vegetation the whole microclimate of Habitat I showed more extremes than any other habitat. Microclimatic conditions in Habitat IV were most stable.

EXAMPLES OF MICROCLIMATES

A recent newspaper article reported that the airplane hangar at a nearby airbase was "so large that it even has its own weather-it was snowing inside the hangar with clear, sunny weather outdoors." The article explained that the humidifier control had gone out of adjustment, raising the relative humidity in the unheated building to nearly 100 per cent, and that the outdoor temperature meanwhile dropped from 37 degrees to 29 degrees Fahrenheit, condensing the moisture directly into snow. In this interesting report of a microclimate, one phrase is somewhat misleading, namely: "So large that it has its own weather." Any building or other enclosed space, no matter how large or small, has its own weather. In the houses in which we live, we control this weather; furnaces, stoves, air conditioners, fans, humidifiers, de-humidifiers, window shades, awnings, overhanging roofs, nearby shade trees-these and other d~vices keep the "climates" in our houses more or less as we want them.

Figure 13 shows two small jars with the lids soldered together and an opening cut through the attached lids. This two-jar arrangement enables you to produce experimental microclimates. For example, you can put a black paper or cloth cover over one jar, and put a thermometer in each jar. Be sure the bulbs are at the bottom ends of the jars. If the thermometers are longer than the jars, let them extend through the lids. You can now see the effect of light and shade on temperature, by placing the jars in dim light and in direct sunlight. If you put insects or other small animals in the jars, you can see whether they move into the light or dark. If you put an ice pack around one jar and a heating pad around the other, or in any other way cool one jar and warm the other you can see whether the animals r~act to the differences in temperature. If you put a wet sponge in one jar and thus raise the humidity, then hold a piece of ice against one jar you may cool the air enough to produce a tiny cloud in that jar.

ADJUSTMENT TO MICROCLIMATES

Other species do not control their microclimates in the same manner as do people, but all plants and anim21s live in habitats to which they are adjusted. Living things can adjust themselves to their habitats only if the environmental conditions in the habitat are suitable, throughout the day and night, and throughout the year. For example, any grass or tree that cannot survive an occasional daytime temperature of 100 degrees Fahrenheit in the shade cannot succeed in most places in Kansas. An animal that cannot carry on normal life activities at temperature below freezing can live through a Kansas winter only by finding an environment that remains above freezing or by becoming inactive in an environment protected from predators. Hibernation and "winter sleep" are two ways of surviving the winter; another way is that of a grasshopper which lays its eggs in the ground an inch or two below the surface, and completes its adult life before winter begins. The eggs are dormant during the winter; while dormant they can survive extremely low temperatures.

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Figure 8. The junior author measuring relative humidities. at ground level upper left; at 20 centimeters. lower left; at 5S centimeters, upper right; and at 200 centimeters, lower right

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Figure 9. The anemometer used to measure wind velocity

Many plants also use the grasshopper's way of surviving through the year, by confining their active life periods to the warm part of the year and going into an inactive stage during the winter. The sunflower, for example, produces seeds which can survive temperatures far below freezing. When warm weather returns in the spring, the seeds germinate and grow into plants; these complete their growth and have their seeds ready by the time cold weather returns the following winter.

Some species of birds fly far south to escape freezing temperatures, but lizards and turtles take a shorter trip. Instead of traveling hundreds or thousands of miles southward, they travel a foot or a few feet downward. The underground "climate" is mild enough for them to spend a carefree winter in hibernation. How far down they must go depends on the general climate of the area. In Eastern Kansas the ground seldom freezes more than a foot down, but in North Dakota the freezing depth may be as much as six feet.

Some animals take advantage of micro climates provided by other animals. The flea, for example, finds in the hair of the dog an ideal climate for itself. In other cases the animal may find a suitable microclimate in or on a plant, such as the owl that rears its young in a hollow tree trunk. Sometimes the animals themselves build structures that help to control their climates. Such are the nests of birds and the "tents" of certain caterpillars. Honeybees even "air-condition" their homes, by controlling to a certain extent both temperature and humidity within the hive.

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Figure 10. Measuring wind velocity at ground level. center; at SS centimeters left and at 200 centimeters, right

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Figure 11. Habitat I, top; II, middle; III. bottom

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Figure 12. Two views of Habitat IV

Some animals find ideal microclimates for themselves in the houses and other buildings made by man. We think of mice and roaches as pests, but of course these animals are merely making good use (from their standpoint) of the favorable habitats which people provide for them. In some cases we build shelters intended for certain anjmals, such as barns for cattle and sheep, or houses for wrens or martins. But other animals use them too. Barn swallows as well as cattle live in barns, and house sparrows may move into a martin house before the martins arrive in the spring.

THINGS TO DO

  1. Build a two-jar microclimate.
  2. Visit a greenhouse, which is a highly organized microclimate.
  3. Build a miniature greenhouse.
  4. Build a hotbed or a cold frame.
  5. Build a bird house.
  6. Build an incubator.
  7. Find different kinds of micro environments near the home or school.

a. grasslands
b. woods
c. under rocks (in prame, in woods, in ripples of streams)
d. in rotting logs
e. at the edge of the pavement
f. marsh or swamp
g. pond or small lake
h. roadside ditch
i. holes and burrows in the ground
j. the underside of a bridge
k. insect galls
l. inside the husk of a corn ear
m. in the seed pod of the yucca
n. in holes in trees

8. Visit an official weather station.
9. Set up a home-made weather station, thermometer, rain gauge.
10. Using several thermometers, check various microenvironments at various times and in various places around the school.
11. Notice the changes in temperature, humidity, and wind velocity as you take a leisurely drive along a country road, for example:

a. from a pasture into a wooded area or vice versa,
b. descending a hill into a valley,
c. along a creek or river,
d. through road cuts,
e. from a newly plowed field to an alfalfa field.

FOR YOUR LIBRARY

Blair, Thomas A. 1948. Weather Elements. 3rd ed. Prentice-Hall, New York. 373 pp.

Climate and Man, 1941 Yearbook of the United States Department of Agriculture, Government Printing Office, Washington. 1248 pp.

Daubenmire, R. J. 1947. Plants and Environment. John Wiley and Sons, Inc. New York. 424 pp.

Flora, S. D. 1948. Climate of Kansas. Report of the Kansas State Board of Agriculture, Vol. 67, No. 285. 320 pp.

Franklin, J. B. 1955. Climates in Miniature. Philosophical Library, New York, 137 pp.

Geiger, R. 1957. The Climate Near the Ground. Harvard University Press, Cambridge, Mass. 494 pp.

Hays, H. A. 1958. The effect of microclimate on the distribution of small mammals in a tall-grass prairie plot. Tran. Kan. Acad. Sci., 61 (I): 40-63.

Lehr, Paul E., R. Will Burnett, and Herbert S. Zim. 1957. Weather Golden Press, New York. 160 pp. (A Golden Nature Guide)

Robinson, T. S. 1957. Ecology of bobwhite in south·central Kansas. Univ. Kan. Publ. Mus. Nat. Hist., Misc. Publ. No. 15. 84 pp. \Unit on microclimate and the Bobwhite, pp. 54-73.

Wolfe, J. N., R. T. Wareham, and H. T. Scofield. 1949. Microclimates and macroclimates of Neotoma, a small valley in central Ohio. University Ohio Publ., Ohio Biological Surv. Bul. 41, 8 (I) 267 pp.

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Figure 13. A microclimate can be contained and controlled in two small jars.

 

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Figure 14. Average daily and seasonal variations in relative humidity at ground level and at 20, 55, and 200 centimeters above the ground in Habitat I

 

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Figure 15. Average daily and seasonal variations in air temperature at ground level and at
two, six, 12, 20. 30, and 40 centimeters above the ground in Habitat II

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Figure 16. Average daily and seasonal variations in wind velocity at ground level and a t 55 and 200 centimeters above the ground in Habitat III; the number tabulated for each observation is the mean between the maximum and minimum readings for the period of observation

 

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Figure 17. Wind velocities in Habitat IV; note the differences between these graphs and those
in Figure 15.

 


FUTURE NUMBERS OF THE KANSAS SCHOOL NATURALIST

 

The publication schedule of The Kansas School Naturalist is quite flexible and indefinite, but plans are taking shape for several future numbers. An early one will be "Insects," by Ron Aeschliman, the first Naturalist to be written by an undergraduate student. The 1963 Workshop in Conservation has been working on two possible numbers, one on animal behavior and one on the camping and picnic locations in Kansas. An issue on the aeneral geology of Kansas is in the makir;, and wIll no doubt appear within the next year. Additional numbers in the three series - Recent Science Books for Children, Let's Build Equipment, Let's Experiment - are in progress.

Suggestions are always in order, both for desirable topics for future Naturalists, ;md for authors or groups of authors to write them.

 


The Department of Biology presents the seventh AUDUBON SCREEN TOUR SERIES in 1963-1964. This series consists of five all-color motion pictures of wildlife, plant science, and conservation personally narrated by leading naturalists. All pictures are presented in Albert Taylor Hall at 7:30 p.m. on the dates listed below. Both group and single admission tickets are available; for further information write Dr. Carl W. Prophet, Department of Biology, KSTC, Emporia.

 

Charles T. Hotchkiss, Teton Trails, Oct. 4. 1963
Chester P. Lyons, Nature's Plans and Puzzles, Dec. 2. 1963
Roy E. Coy, Manitoba Memories, Jan. 9. 1964
Harry Pederson, Village Beneath The Sea, Feb. 18. 1964
Eben McMillan, Land That I Love, March 5. 1964


IT IS NOT TOO EARLY to think about the 1964 Workshop in Conservation, which will be a part of the 1964 Summer Session of the Kansas State Teachers College. As in the past, the Workshop will cover water, soil, grassland, and wildlife conservation, with emphasis on conservation teaching. There will be lectures, demonstrations, discussion groups, films, slides, field trips, projects, and individual and group reports. You may enroll for undergraduate or graduate credit.

Exact dates, fees, and other details will appear in later issues of The Kansas School Naturalist. For further information write the director, Mr. Thomas A. Eddy, Department of Biology, KSTC, Emporia.


PREVIOUS ISSUES

Oct. 1954, Window Nature Study;

Dec. 1954, Wildlife in Winter;

Feb. 1955, Childrens' Books for Nature Study (First in a series);

April 1955, Let's Go Outdoors;

Oct. 1955, Fall Wildflowers;

Dec. 1955, Snow;

Feb. 1956, Spring Wildflowers;

April 1956, Turtles in Kansas;

Oct. 1956, Hawks in Kansas;

Dec. 1956, Childrens' Books for Nature Study (Second in the series);

Feb. 1957, Life in a Pond;

April 1957, Spiders;

Oct. 1957, Along the Roadside;

Dec. 1957, An Outline for Conservation Teaching in Kansas;

Feb. 1958, Trees;

April 1958, Sum­mer Wildflowers;

Oct. 1958, Watersheds in Kansas;

Dec. 1958, Let's Build Equipment;

Feb. 1959, Poisonous Snakes of Kansas;

April 1959, Life in a Stream;

Oct. 1959, Field Trips;

Dec. 1959, Conservation Arith­metic;

Feb. 1960, The Sparrow Family;

April 1960, Measures and Weights;

Nov. 1960, Let's Experiment;

Jan. 1961, Recent Science Books for Children;

March 1961, The Greatest Show on Earth;

May 1961, The F.B. and Rena G. Ross Natural History Reservation;

Nov. 1961, Rhythms in Nature;

Jan. 1962, The Cacti of Kansas;

March 1962, The Formation of Soil;

May 1962, Let's Build Equipment;

Nov. 1962, Terns of Kansas;

Jan. 1963, Kansas Natural History in 1863;

March 1963, Attracting Wildlife for Observation;

May 1963, The Water Table.

Those printed in boldfaced type are still available, free of charge except Poisonous Snakes of Kansas, which is sold for 25¢ per copy postpaid, to pay for the increased printing costs due to the color plates.

The out-of-print issues may be found in many school and public libraries in Kansas.


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