Don’t Litter the Stream: An Invasive Tree Species and a Hawaiian Stream Food Web
From 1920 to 1950, a tree species called albizia (Falcataria moluccana) was brought to Hawai‘i from islands located north and northeast of Australia. A fast-growing tree, albizia now grows all over Hawai‘i and is taking over the places where native trees have grown. The scientists in this study had observed an increase in nitrogen in some Hawaiian streams. The places where nitrogen was increasing were areas with albizia trees growing along the streams. The scientists wanted to know if aquatic organisms were eating the albizia leaf litter instead of the native algae, thus changing the nitrogen concentrations in Hawai'i's food webs.
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In this FACTivity, you will answer the question: What are some ways that albizia leaves may be changing the Hawaiian stream food web? Materials: Food web circles (included) Paper for...FACTivity – Don’t Litter the Stream!
In this FACTivity, you will answer the question: What are some ways that albizia leaves may be changing the Hawaiian stream food web? Materials: Food web circles (included) Paper for...
Glossary
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Trisha Atwood
My favorite science experience was when I was collecting a tissue/DNA sample from a dead whale floating off the coast of Hawai‘i so that we could try and identify what...View Profile -
Tracy Wiegner
My favorite science experience was hiking along the Waipi‘o Valley rim in the cloud forest to collect samples from the streams dropping into the valley. I lay in the streambed...View Profile -
Jason Turner
I think every day is my greatest science day because, in this field, you never know what is around the corner. Last week, I helped recover the lower jaw of...View Profile -
Richard MacKenzie
When I was little, I used to come home from the creek behind our house covered in mud. I still do. I love that I get to study fish, insects,...View Profile
Standards addressed in this Article:
Social Studies Standards
- Culture
- Global Connections
- People, Places, and Environments
- Power, Authority, and Governance
- Production, Distribution, and Consumption
- Science, Technology, and Society
Note To Educators
The Forest Service's Mission
The Forest Service’s mission is to sustain the health, diversity, and productivity of the Nation’s forests and grasslands to meet the needs of present and future generations. For more than 100 years, our motto has been “caring for the land and serving people.” The Forest Service, an agency of the U.S. Department of Agriculture (USDA), recognizes its responsibility to be engaged in efforts to connect youth to nature and to promote the development of science-based conservation education programs and materials nationwide.
What Is the Natural Inquirer?
Natural Inquirer is a science education resource journal to be used by students in grade 6 and up. Natural Inquirer contains articles describing environmental and natural resource research conducted by Forest Service scientists and their cooperators. These scientific journal articles have been reformatted to meet the needs of middle school students. The articles are easy to understand, are aesthetically pleasing to the eye, contain glossaries, and include hands-on activities. The goal of Natural Inquirer is to stimulate critical reading and thinking about scientific inquiry and investigation while teaching about ecology, the natural environment, and natural resources.
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Meet the Scientists
Introduces students to the scientists who did the research. This section may be used in a discussion about careers in science.
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What Kinds of Scientist Did This Research?
Introduces students to the scientific disciplines of the scientists who conducted the research.
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Thinking About Science
Introduces something new about the scientific process, such as a scientific habit of mind or procedures used in scientific studies.
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Thinking About the Environment
Introduces the environmental topic being addressed in the research.
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Introduction
Introduces the problem or question that the research addresses.
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Method
Describes the method the scientists used to collect and analyze their data.
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Findings & Discussion
Describes the results of the analysis. Addresses the findings and places them into the context of the original problem or question.
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Reflection Section
Presents questions aimed at stimulating critical thinking about what has been read or predicting what might be presented in the next section. These questions are placed at the end of each of the main article sections.
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Number Crunches
Presents an easy math problem related to the research.
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Glossary
Defines potentially new scientific or other terms to students. The first occurrence of a glossary word is bold in the text.
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Citation
Gives the original article citation with an internet link to the original article.
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FACTivity
Presents a hands-on activity that emphasizes something presented in the article.
Science Education Standards
You will find a listing of education standards which are addressed by each article at the back of each publication and on our website.
We Welcome Feedback
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Contact
Jessica Nickelsen
Director, Natural Inquirer program -
Email
Lessons
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In this lesson, students will increase their reading comprehension, critical thinking skills, and summarization and explanation skills. Students will role-play as members of the Natural Inquirer Twitter Team (now X...Lesson Plan – Twitter Team
In this lesson, students will increase their reading comprehension, critical thinking skills, and summarization and explanation skills. Students will role-play as members of the Natural Inquirer Twitter Team (now X... -
This lesson plan can be paired with any of the cultural essays from the Hawai’i-Pacific Islands edition of Natural Inquirer. After a brief introduction, students will read the cultural essay...Lesson Plan – Cultural Essay
This lesson plan can be paired with any of the cultural essays from the Hawai’i-Pacific Islands edition of Natural Inquirer. After a brief introduction, students will read the cultural essay... -
In this lesson plan, students learn about invasive species in their area and create brochures educating others about their characteristics. Materials: Internet or library access for research Paper and writing...Lesson Plan – Invasive Species
In this lesson plan, students learn about invasive species in their area and create brochures educating others about their characteristics. Materials: Internet or library access for research Paper and writing...
Education Files
Water Is Wealth
For early Hawaiians, life revolved around water (“wai”). Wai was the source of land and man. It gave life to food, plants, and vegetation. For most Hawaiians, water also produced the staff of life—kalo (or taro, a root crop). Having an abundance of water on your land demonstrated your wealth. The word “Waiwai” means wealth, prosperity, ownership, possession. Literally it is “water-water.” Wai was the possession of no man, even chief (“ali‘i”) or king (“mō‘ī”). Every family that lived on and cultivated the land used a given water source. To have a right to use the water, the family would help to maintain the water source. If the family did not use or help to maintain the water source, they had no right to claim it.
Taro growing in a wetland in Waipi‘o Valley. Taro has been an important food crop for Hawaiians.
Dividing Wai–Ahupua‘a System
In old Hawai‘i, districts, lands, and lots were subdivided into “ahupua‘a”, the chief political system. Each ahupua‘a stretched from the seashore up into the mountains. Ridges, rocks, stream channels, and sometimes a tree would mark the boundaries. At the seashore of each ahupua‘a, an altar of rocks (“ahu”) would be placed with a wooden image of a pig (“pua‘a”) to mark the boundaries; thus, the word “ahupua‘a.” Offerings were also placed on the ahu for the rain god or to pay tax to the chief of the ahupua‘a. This system assured sustenance and survival through the exchange and sharing of food, fish, water, firewood, house timbers, and thatch between the tenants and chief. It also ensured that the land would be cared for from the mountaintops to the sea.
Within the ahupua‘a, streams or “kahawai” (“the place having fresh water”) ran from the upland forests and below. To the Hawaiian farmer (“mahi‘ai”), the kahawai was particularly important. Along or below the streams, the farmer would tap into the water by making an irrigation ditch (“‘auwai”). The ‘auwai diverted water into his or her taro patch (“lo‘i kalo”) (see above), medicinal herbs, or flower farm. The ali‘i had a supervisor (“konohiki”) to allocate water fairly and coordinate the building of the ‘auwai.
Law and Water Rights
The law of the land came down to water rights. Law in Hawaiian is “kānāwai”, meaning “belonging to the waters.” This law indicated an equal sharing of water. Inhabitants of each ahupua‘a depended on the water system. The Hawaiian farmer would take as much water as needed for his farm and then would close the inlet so that the next farmer could take his needed share. Everyone would get their needed share of water, while looking after their neighbors’ rights as well, without greed or selfishness. The ali‘i nui (“great chief”) of the ahupua‘a had authority and power but not a “divine right.” Since wai was something that belonged to Kane-i ka-wai-ola (the Hawaiian god of water), the al‘i nui did not exercise personal authority but instead provided his people with their rights to water and life. Ali‘i nui who abused this role were at times rejected or killed. These harsh actions demonstrated the importance of rights (“pono”) within the social system.
Streams ("Kahawai")
The kahawai provided not only wai, but also food. Hawaiians, most often women (“wahine”), regularly used one-person scoop nets in streams for catching food. The small nets were used to catch crabs, fresh-water shrimp (“‘opae”), and ‘o‘opu, a fresh-water fish known for its ono (“delicious”) taste. The branches of the endemic shrub ‘ūlei (Osteomeles anthyllidifolia) are easily bendable into a loop. The branches can be lashed together with cord, forming a handle to the net. Fishers also placed traps (“hīna‘i”) in the streambed to catch ‘opae and ‘o‘opu. The traps were more like baskets and were made from the roots of ‘ie‘ie or the vines from the ‘āwikiwiki (Canavalia galeata).
Celebrating Water Today
Water remains a valued natural resource in Hawai‘i. Hawaiians interested in traditional values joined Hawaiian graffiti artists Estria Miyashiro and John “Prime” Hina in a special project in 2011. Together, they created the third Water Writes mural. The artists painted the Hawaiian mural, which is over 7.5 meters (25 feet) high and 70 meters (200 feet) long, in Honolulu. The mural celebrates the relationship between Hawaiians and water.
Recently students in Hilo, HI, took a field trip to a forested stream. Forest Service scientists taught these students about stream ecology and goby fish found only in Hawai‘i. As a part of a program called FOCUS (Forests, Ocean, Climate and Us), the students later painted a mural showing the goby fish in their native environment. Dennis Taniguchi of the East Hawai‘i Cultural Center guided the mural’s creation. As is usual for Hawaiians interested in keeping the traditional culture alive, art is used to celebrate aloha ‘āina, or “love of the land.” These two examples, however, show that Hawaiians today also like to celebrate their love of water. Like Hawaiians throughout history, they know that water is wealth.
Students learn about goby fish and stream ecology during a field trip.
Detail from the goby mural painted by Hawaiian students.