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Biodiversity in Yokohama

Last Updated March 1, 2023

Biodiversity in Yokohama

Creatures in Yokohama

Yokohama City is a large city with a population of more than 3.7 million (as of December 1, 2018), but there are many forests and farmlands that are cohesive in places close to citizens, mainly in the suburbs. It is characterized by a variety of natural environments due to the sea, rivers, and undulating terrain. However, the green coverage of the city area is on a downward trend, and as of 2009, it is less than 30%.
The following points are the background and issues of the biodiversity crisis in Yokohama City.

  • Loss, fragmentation, and deterioration of habitats and habitats due to land use modifications associated with development
  • Degraded habitat and growth environment of living creatures due to inadequate management
  • Lack of comprehensive accumulation of biological survey data
  • Changes in lifestyles and consciousness due to improvements in the convenience of life
  • Lack of initiatives that consider biodiversity

As the importance of biodiversity is attracting worldwide attention, it is necessary to share these backgrounds and issues with citizens in the metropolis of Yokohama and connect rich Yokohama-like biodiversity to future generations.

Invasive creatures in Yokohama

Photograph of black bass

"Exotic organisms (exotic species)" refers to creatures that were not originally in the area but came in from other areas through human activities. There are many creatures that originally lived and did not grow in Yokohama, such as those brought in as pets and became wild, and those that were attached to ships.
Some alien species are subject to control as damage to or may damage ecosystems, human life and body, agriculture, forestry and fisheries, but have once spread outdoors It is difficult to eradicate alien species and requires a great deal of effort.
In order to connect Yokohama-like biodiversity to future generations, the main principle is "do not enter," "do not throw away," and "do not spread" alien species.

Efforts on Biodiversity at the Institute of Environmental Science

City biota survey

In Yokohama City, we have conducted several biological habitat surveys, mainly by the Institute for Environmental Science. In particular, we conduct surveys on rivers and seas in the city almost every three years since 1973. Please refer to the Environmental Data page for results and reports.

River area

Photo of Ayu

We investigate fish, benthic animals, aquatic plants, attached algae, etc. for the six water systems of rivers flowing through the city, and evaluate the water environment of rivers from creatures.
The survey has been conducted almost every three years since 1973, and the 15th survey was conducted in FY2018 and FY2019.

Sea area

Photo of Hattate Numeri


We conduct surveys on fish, coastal animals, seaweeds, plankton, etc. at the estuaries, coasts, and inner bays in the city, and evaluate the water environment of the sea from creatures.
The 14th survey was conducted in FY2016.

Headwaters and ponds

Photographs of creatures in the current basin and pond

From fiscal 2004 to fiscal 2008, we conducted a basic survey on water environment in the headwaters of major rivers in Yokohama and surrounding areas to utilize them for the restoration of conservation in the headwaters and environmental activities.
In addition, we carried out biota investigation in four ponds in the city and one educational paddy field in 2010.

Land area

In Yokohama City, we conducted biota and ecosystem surveys in the land area of Yokohama City from 1986 to 1990, 1997 and 10, and then conducted surveys in limited areas such as headwaters and parks.
Since FY2012, based on the Yokohama Action Plan for Biodiversity (b Plan), land biota surveys (plants, mammals, birds, reptiles, amphibians, insects) have been conducted.

Biophysological survey points in land area
Basin Survey points
Ookagawa Basin Hitorizawa Citizen's Forest, Kuraki Park, Yokohama Park Yamashita Park
Tsurumi River Basin Shinji Citizen's Forest, Shin-Yokohama Park, Shishigaya Citizen's Forest
Katabira River Basin Children's Nature Park, Jingashita Keikoku Park, Nogeyama Park
Sakaigawa Basin Seya Mukubo Park, Tenno Moriizumi Park, Maioka Park

Survey by elementary school students

Questionnaire for survey of creatures by elementary school students

Since fiscal 2013, the Institute for Environmental Science has been conducting surveys of living creatures throughout Yokohama, with the aim of raising citizens' interest in nature and living things in the region and acquiring basic data that contributes to the biodiversity conservation.

Accumulation and disclosure of biological data

River creature survey point map

In Yokohama City, departments other than the Institute for Environmental Science are also conducting surveys on biological habitats. We accumulate the status of these surveys and information on biological habitats, and disclose (partly) data.

Publishing booklets, etc.

Booklets (the creatures on the waterside of Yokohama Tando)

The results of the biopharmace survey are published in the survey results report and the summary version of the survey results, but a booklet has been created to make it easier to use and use in the environment in Yokohama.

・Click here for the booklet

Reflection to Measures

In implementing measures that take biodiversity into account, it is very important to understand the current status and changes in the living conditions in the city.
The Institute for Environmental Science contributes to the formulation of various plans and guidelines related to biodiversity by analyzing survey results and examining methods for evaluating the environment and ecosystems.

Example 1 Evaluation of the water environment by biological indicators

Table of water environment evaluation using biological indicators

We evaluate the aquatic environment by setting indicator organisms based on accumulated data from research institutes on aquatic organisms.

  • Research reports on water area biological indicators
  • Report on Revision of River Biological Indicators

Example 2 Quality evaluation of parks and green spaces

We organized technical requirements for the creation of parks and green spaces in consideration of biodiversity, evaluated the familiar natural environment using the newly developed Ecosystem Soundness Simple Evaluation Method, etc., and announced it in the 2nd Green Technology Forum 2008 (May 2008).

Plans and Guidelines for Biodiversity

You may need a separate PDF reader to open a PDF file.
If you do not have it, you can download it free of charge from Adobe.
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Inquiries to this page

Environmental Science Research Institute, Environmental Conservation Department, Green Environment Bureau

Telephone: 045-453-2550

Telephone: 045-453-2550

Fax: 045-453-2560

Email address: mk-kanken@city.yokohama.lg.jp

Return to the previous page

Page ID: 354-346-751

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