4th Grade - Science

LESSON PROBLEM: Ecology: Amphibians, birds, and mammals have found homes in rice fields or paddies. Why has this happened?


STUDY GUIDE

Small creeks or major rivers create one of the natural habitats or ecosystems for all kinds of animals. Within small ponds and lakes many different species from tiny insects to large mammals feed and breed in the safety of grasses and wetlands.

United States rice farmers have worked hard to provide ecosystems for the benefit of the wildlife and ecology. Flooded rice fields provide man-made ecosystems for wildlife that have lost their natural homes due to development. Rice ecosystems require plentiful water and are characterized by elevation, soil types, rainfall patterns, depth of flooding and drainage. The rice farm wetlands habitats are critical to the survival of migrating waterfowl, in addition to providing a year round habitat for mammals, reptiles, and several types of shorebirds. Let's explore the different kinds of wildlife that occupy rice habitats during their annual cycle of life.

Millions of migrating and other water birds are counted each year in and near the rice fields of Arkansas, California, Louisiana, Mississippi, Missouri, and Texas. About 141 species of birds, 28 species of mammals and 24 species of amphibians and reptiles are known to occupy rice habitats in the Sacramento Valley of California, alone.

Rice fields are flooded for most of the year, about ten months from spring through winter. The rice fields are flooded at the start of the rice growing season and remain flooded thoughout the growing season. They are drained for a couple of weeks so the rice can be harvested and then they are reflooded for the migrating waterfowl. The rice fields are not drained again until it is time to prepare the fields for replanting. These temporary wetlands have great significance for feeding and sheltering birds, amphibians, and mammals. Migratory waterfowl and shorebirds also use rice habitats on their journey southward.

Grasslands and forests may grow close together to form a complex of habitats that support enormous flocks of ducks, geese, swans and cranes; toads, lizards and snakes; and rabbits, mice, squirrels, and beavers. Depending on the water level and access to trees and shrubs, these mammals and amphibians eat, breed, and build nests.

Waterfowl include migrating ducks, geese and cranes, as well as, shorebirds such as egrets, herons, gulls, sandpipers and pelicans. Doves, larks, pheasants, robins, wrens, blackbirds, swallows and woodpeckers are also visitors to the rice wetlands. Dropped grain, left after the rice is harvested, is a major source of food for the waterfowl species. The farmer benefits by receiving natural fertilizer left behind in the droppings of these feeding flocks. There are some special larger birds that use rice fields. These are eagles, hawks, vultures and owls who eat smaller birds, rodents and reptiles in the ongoing cycle of life. A total of 27 different birds have been identified in California rice fields.

Reptiles, such as turtles, snakes, frogs, salamanders and lizards are often found in rice fields. Since they need land, they are most often found in swamps or marshes rather than well-drained soil on a sloping field.


Mammals found near rice paddies or fields are opossums, jackrabbits, gophers, rats, coyotes, foxes, minks, skunk, otter and deer. These animals might be found near the non-flooded areas or uplands close to forests.

Farmers plant rainfed rice on land near larger urban areas where they have flat land or lowlands. The yield of rice depends on rainfall and farming practices. These areas are usually in the heavily populated rural and urban regions, which make up about 20% of the world population.

Rice is grown in upland and irrigated ecosystems. The upland ecosystem is one that uses only water from rainfall for the rice fields. The irrigated ecosystems use an irrigation system to keep the rice fields flooded. The upland rice ecosystem has a rainy season and is usually found at the mouth of rivers where flooding is sometimes uncontrolled.

The irrigated rice ecosystem uses water from wells, rivers and canals, and rain efficiently controlled by irrigation systems. Which wildlife group would prefer to live near these rice areas?




ACTIVITIES

Make a chart of all the wildlife known to use the rice ecosystems as home.

Use poster board and draw a bar graph, circle graph or flow chart to show the kinds of habitats and link them to the kind of wildlife found there.

For example, flood-prone habitats on the left of a bar graph can be linked to the amphibians on the bottom of the graph.

Use colored markers to design your own way to show the four rice ecosystems. Then determine which group of wildlife would be found there.
Sometimes two or three groups of wildlife might be found in one ecosystem.

Have a friend help you with this project.



EXTENDED LEARNING

Go onto the Internet or look for a list of wildlife species in rice ecosystems and find pictures in magazines to cut out and then match.

When you cannot locate a picture to trace from an encyclopedia or picture, try to draw it. Go to the library and find pictures you can copy.

Try to draw the birds, amphibians and mammals as accurately as possible, that is, following the correct colors that help to camouflage them in the wild.

Perhaps your pictures can be surrounded by rice fields showing acres of short or tall rice grasses.

Enjoy yourselves!




VOCABULARY

  • ecosystem
  • habitat
  • amphibians
  • sloping
  • elevation


Click here to play Rice Rampage!
Anatomy of Rice:
Rice is a seed of cereal (grass) plant used for food. Click here to learn more about the Anatomy of Rice.
Home | Math | Social Studies | Science | Health | Games | Students



© 2004 USRPA, A non-profit association based in Houston, Texas
All Rights Reserved

USRPA does not discriminate in its programs on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, or marital/family status. Persons with disabilities who require alternative means for communication of information (such as Braille, large print, sign language interpreter) should contact USRPA at 713-974-7423.