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.
After the article, read a short essay about the importance of water to early Hawai'ians.
You can also read the cultural essay separately in the Cultural Essay tab below.
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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...
Standards addressed in this Article:
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ESS3.C-M1
Human activities have significantly altered the biosphere, sometimes damaging or destroying natural habitats and causing the extinction of other species. But changes to Earth’s environments can have different impacts (negative and positive) for different living things.
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LS1.C-M1
Plants, algae (including phytoplankton), and many microorganisms use the energy from light to make sugars (food) from carbon dioxide from the atmosphere and water through the process of photosynthesis, which also releases oxygen. These sugars can be used immediately or stored for growth or later use.
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LS1.C-M2
Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy.
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LS2.A-M1
Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors.
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LS2.A-M2
In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction.
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LS2.A-M3
Growth of organisms and population increases are limited by access to resources.
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LS2.A-M4
Similarly, predatory interactions may reduce the number of organisms or eliminate whole populations of organisms. Mutually beneficial interactions, in contrast, may become so interdependent that each organism requires the other for survival. Although the species involved in these competitive, predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of organisms with their environments, both living and nonliving, are shared.
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LS2.B-M1
Food webs are models that demonstrate how matter and energy are transferred between producers, consumers, and decomposers as the three groups interact within an ecosystem. Transfers of matter into and out of the physical environment occur at every level. Decomposers recycle nutrients from dead plant or animal matter back to the soil in terrestrial environments or to the water in aquatic environments. The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and nonliving parts of the ecosystem.
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LS2.C-M1
Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations.
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LS2.C-M2
Biodiversity describes the variety of species found in Earth’s terrestrial and oceanic ecosystems. The completeness or integrity of an ecosystem’s biodiversity is often used as a measure of its health.
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PS1.A-M1
Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.
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PS1.B-M1
Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.
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Cite specific textual evidence to support analysis of science and technical texts.
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By the end of grade 8, read and comprehend science/technical texts in the grades 6-8 text complexity band independently and proficiently.
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Determine the central ideas or conclusions of a text; provide an accurate summary of the text distinct from prior knowledge or opinions.
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Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks.
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Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.
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Analyze the structure an author uses to organize a text, including how the major sections contribute to the whole and to an understanding of the topic.
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Analyze the author's purpose in providing an explanation, describing a procedure, or discussing an experiment in a text.
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Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).
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Distinguish among facts, reasoned judgment based on research findings, and speculation in a text.
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Compare and contrast the information gained from experiments, simulations, video, or multimedia sources with that gained from reading a text on the same topic.
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Culture
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People, Places, and Environments
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Power, Authority, and Governance
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Science, Technology, and Society
What Is a Natural Inquirer Journal?
A Natural Inquirer journal is a collection of 4-8 articles on a related science topic. Journals are written for a middle school audience, but they can also be adapted for both high school students and advanced upper elementary students. Some journals are particularly suited to high school students; you can find our grade level recommendations in the tags on the product page or by filtering journals by grade level.
Journals include:
- Four to eight articles based on published, peer-reviewed research papers; the articles keep the research paper format (see more below) but are written in language students can understand.
- A FACTivity for each article, which is an activity to complete after reading the article. The FACTivity helps reinforce major science concepts from the article. These activities are designed to be easy to implement, with few material requirements and options for adapting them for your audience or available resources. Some articles in a journal may have two FACTivities.
- A short “Welcome to the journal” article about key background information and science concepts that unify the articles included in the journal
- A glossary of new terms for each article and the introductory materials.
- A list of related Natural Inquirer publications for each article as well as outside references.
- Standards correlations, including Next Generation Science Standards, addressed in the articles and the FACTivities.
Journals may also include additional essays (called spotlights), other activities (like crossword puzzles or vocabulary challenges), and more.
Reading Modes
Journals are available in three different formats:
- Hard copies can be ordered from the website and shipped, all free of charge.
- PDF versions of the printed journal can be downloaded free on the website. The PDF version directly replicates the content and layout of the printed version. You can also download individual articles as pdfs.
- The “Read Distraction Free” option allows the individual articles to open in their own window, without the rest of the website being visible. These articles can be found under the “Articles” tab. This version allows readers to scroll to particular sections of the article using the sidebar menu on the left side of the screen. This version also has interactive Reflection Sections and Number Crunches. Students can enter their answers, submit them, and then receive the correct answers to double-check their work. Submitted answers are not saved on the website and will disappear once the window is closed.
What's in a Natural Inquirer Article?
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Meet the Scientists
This section introduces the scientists (and others) who worked on the study. In their own words, they each share a memorable science experience, a favorite research project, or something they learned during the course of their education or research.
Use this section to:
- Introduce kids to the variety of people who work in science
- Introduce kids to the variety of scientific fields and give brief descriptions of science-related jobs
- Explore ways that people interact with science every day
Next Generation Science Standards (NGSS) applications:
- Science and Engineering Practices
- Crosscutting Concepts: Influence of Science, Engineering, and Technology on Society and the Natural World
Note that specific standards for this particular journal are linked on this educator guide tab.
Other resources:
Many of the scientists and engineers featured in this section are also featured on our collector cards. Learn more about their work, how they got interested in their fields, and interesting projects they worked on. Cards can be printed as posters, too.
Thinking About Science
This section briefly describes a concept about science or scientific research. This overview can touch on topics like
- study type (longitudinal study, quantitative vs. qualitative data),
- behaviors of scientists (conducting literature reviews, collaborating with other specialists, replicating earlier studies),
- the practice of science (the scientific method, engineering design, data collection, randomization, controls and variables),
- or other aspects of science (bias, correlation vs. causation).
Use this section to:
- Reinforce steps in the scientific method and the process of science
- Encourage students to think about the practice of science and what it can and cannot tell us
- Consider the many types of scientific study and what information each type can provide
Next Generation Science Standards applications:
- Science and Engineering Practices
- Life Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.
Other resources:
You can use key words to search for other or related scientific topics on our website (e.g. “longitudinal study,” “bias,” or “sampling”).
Thinking About the Environment
This section provides a brief overview of a topic or concept in environmental/life science. The topic or concept is directly related to the research study that follows. Examples of topics include the carbon cycle, the water cycle, habitat fragmentation, phenology, biodiversity, and ecosystem services.
Use this section to:
- Provide important background information to help students understand the research study
- Serve as a quick reference during reading or class instruction
- Connect the research article with other activities or media on the same topic
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.
Other resources:
You can use key words to search for more resources on life or earth science topics on our website (e.g. “habitat,” “carbon,” or “genetics”).
Introduction
This section begins the scientific article format. Much like the published, peer-reviewed study this article is based on, the introduction provides background information for the study – what is currently known and what remains unknown. The introduction culminates in the question(s) the study hopes to answer.
The introduction is also the first section with a Reflection Section. This section includes two or three questions to help kids reflect on what they’ve just learned in the Introduction. If they are using the online distraction-free reading mode, they can answer these questions directly on the website.
Use this section to:
- Review important background information that kids need to understand the study
- Connect the study to the concepts addressed in the Thinking About Science and Thinking About the Environment sections
- Understand research questions and hypotheses, including generating their own hypotheses given what they already know
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.
Other resources:
Use one of the guided reading lesson plans to help kids follow the format of a scientific paper.
Methods
This section is the nuts and bolts of the study design – the who, what, when, where, why, and how of the research. Contained within the Methods section are usually maps of the study location or the set-up of study plots, as well as details about what data was collected and how.
The Methods section also ends with a Reflection Section – two or three questions to help students think through what they just read. These questions are interactive on the distraction-free reading mode.
Use this section to:
- Show students how experiments and studies are designed and carried out
- Explore sampling methods and randomization
- Introduce various data collection tools (e.g. camera traps, surveys, insect collection tools, weather stations, etc.)
- Explain bias and how studies are designed to remove bias
- Help students gain experience with map reading
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.
Other resources:
Many Methods and Findings sections contain Number Crunches, which are simple math exercises designed to help students interact with the data from the study.
Findings
This section summarizes the data collected during the study. The Findings section usually includes data tables or graphs and highlights the significant data points from the study. This section often mentions statistical analysis or the use of computer programs to model or analyze the data, though these methods are only discussed generally.
The Findings section also ends with a Reflection Section – two or three questions to help students think through what they just read. These questions are interactive on the distraction-free reading mode.
Use this section to:
- Have students practice reading and interpreting graphs and tables
- Compare results between variables and controls
- Explain the concept of statistical significance
- Discuss how no data or negative results still provide valuable information
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.
Other resources:
Search the website for “map” or “graph” to find activities where students can practice making and reading maps and graphs.
Discussion
This section concludes each article. In it, we summarize the main findings of the scientists’ study. Additionally, we present the scientists’ ideas about the limitations of their study, the big-picture impacts of their research, and the scientists’ plans for future study or action.
The Discussion section ends with a Reflection Section – two or three questions to help students think through what they just read, especially general take-aways from the study. These questions are interactive on the distraction-free reading mode.
Use this section to:
- Discuss what conclusions can and cannot be drawn from the available data
- Explain the difference between correlation and causation
- Explore study limitations and opportunities for further study
- Brainstorm ways the study findings could be applied to real-world situations
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.
Other resources:
Use the “Designing Your Own Study” resource page for videos of scientists discussing their own research studies. The page also includes educator resources to help students plan their own scientific studies.
Additional Resources on the Website
On the website, we pair each journal with a variety of other resources, as well. Use the tabs on the product page to browse through the following:- Related activities, including the FACTivity for each article
- An “About” essay that gives some larger context for the research the scientists conducted or more information about the science topic from the journal
- A glossary of all boldfaced terms from the journal
- A “Scientists and Collaborators” page that lists the people involved in the studies in the journal; click on a researcher to reach their bio page and see what other articles they might be featured in
- A “Related Content” page that lists both Natural Inquirer resources about similar topics and also outside reference materials
Article Selection and Review
Natural Inquirer partners with the USDA Forest Service, so we source research studies by Forest Service scientists that have been peer-reviewed and published in reputable journals. Some of our articles have also been created in collaboration with scientists from other Federal agencies, such as U.S. Geological Survey and the United Nations Food and Agriculture Organization, universities, and other non-profits.
All journal articles are reviewed by scientists who conducted the original research study to verify scientific accuracy. Journals are also reviewed by student editorial review boards of middle or high school students before publication. Additionally, all journals are reviewed by the Forest Service and the U.S. Department of Agriculture before publication.
Every journal article includes a citation of its source study. Many educators pair the original research paper with our article to help more advanced students learn how to read formal research papers. The journal article then serves as adapted primary literature, bridging the two articles.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
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
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.