International Symposium on Integrated Coastal Management for Marine Biodiversity in Asia, January 14-15, 2010, Kyoto, Japan

Research and Education of the Ecological Links

from Forests to Coastal Waters in FSERC, Kyoto University

Yoh Yamashita Maizuru Fisheries Research Station,

Field Science Education and Research Center, Kyoto University、Japan

yoh@kais.kyoto-u.ac.jp

In Japan, commercial landings from coastal fisheries have shown a continuous decreasing trend

after the peak in the mid 1980’s and are currently only about 65% of the peak years (Fig. 1). There

are four possible causes for this decline: climate change, overfishing, deterioration of the coastal en-

vironment, and deterioration of the natural links between terrestrial areas, rivers and the coastal envi-

ronment. Landings have markedly decreased in semi-enclosed areas which have been greatly influ-

enced by human activities, for example, decline to about 36% and 15% of the peak years in Seto

Inland Sea and Ariake Bay, respectively (Fig. 1). The decline of fishery landings in Kyoto Prefecture

is also serious, only 14% of the peak year. In coastal areas, the fourth factor, in particular, is consid-

ered to play an important role in the decline of biological resources. In addition, unusual ecological

phenomena such as mass occurrences of jellyfish are thought to be closely associated with influences

caused by human activities.

Fishermen instinctively felt that one of the causes was the deterioration of forests and they be-

gan forest plantations several decades ago and these plantations are on going at about 100 sites all

over Japan. However, the effectiveness of the reforestation plantation is not clear and there has been

little scientific evidence to show that healthy forests contribute to healthy biological production in

rivers and coastal waters.

The Field Science Education and Research Center (FSERC) was established in 2003 by combin-

ing nine field-research facilities on forests, wild plants and coastal waters located from Yamaguchi

Prefecture to Hokkaido. As mentioned above, biological productivity and biodiversity in coastal wa-

ters have markedly declined. We found that it is impossible to restore the marine environments based

on research on the marine side alone. Nearly 70% of Japan’s land area is covered by forests and Ja-

pan is completely surrounded by seas. There are areas defined as “Sato” where humans live between

forests and seas. However, scientists in each of these ecological sectors have not collaboratively

worked, in spite that forests, Sato areas, river systems and coastal waters are connected and interde-

pendent. The scientists from different research fields began to work together after the establishment

of FSERC to elucidate the ecological links from forests to oceans. We believe that healthy linkage

through forests, Sato, rivers and oceans is the most important key to restore each ecological unit and

are trying to produce “Connected rings of Forest-Sato-Marine” Program for both research and educa-

tion.

Research activities

Our basic hypothesis is that the decrease of aquatic biological productivity and diversity can be

attributable to disturbed and interrupted ecological links from forests to coastal waters due to 1. in-

creased input of fine sediments to coastal waters from poorly managed artificial forests, paddy fields

and dam lakes etc., 2. disturbed nutrient balance such as C, N, P, Si, Fe from terrestrial areas, 3. arti-

ficial control of river water discharge for human activities, and 4. obstruction of aquatic animal

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International Symposium on Integrated Coastal Management for Marine Biodiversity in Asia, January 14-15, 2010, Kyoto, Japan

Fig. 1. Annual change of

fisheries landings ex-

pressed as percentages

to the maximum amount,

in Japan, the Seto Inland

Sea, Ariake Bay and Kyoto

prefecture.

Fig. 2. Satellite photo-

graph of the Yura River

watershed. Maizuru Fish-

eries Research Station

(MFRS）, Ashiu Forest

Research (AFRS).

Fig.3. Composition of an-

thropogenic matter,

phytoplankton and ben-

thic algae in particulate

organic carbon (POC) col-

lected in the Yura River

between ca. 20 to 120

km from the river mouth

in May and November

2006. (suzuki et al. un-

Fig. 4. The primary pro-

duction system in the

brackish water from river

mouth to ca. 20 km up-

stream (Kasai et al., in

press.).

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International Symposium on Integrated Coastal Management for Marine Biodiversity in Asia, January 14-15, 2010, Kyoto, Japan

ontogenetic migrations by dams and drainage improvement programs of concreting the

banks of the river etc. To understand the ecological links between terrestrial areas and coastal wa-

ters, we have been carrying out the research at three main field areas - the Yura River watershed in

Kyoto, Koza River watershed in Wakayama and Niyodo River watershed in Kochi.

Station and some laboratories in FSERC have been mainly studying the biological production

systems in the Yura River and coastal areas since 2005 (Fig. 2). The Yura River originates from the

Ashiu Forest of Kyoto Prefecture in which FSERC Ashiu Forest Research Station is located and

flows into the Tango Sea where FSERC Maizuru Fisheries Research Station is located. The river has

a length of 146 km and a river basin area of 1880 km2.

Studies have been conducted from a variety of viewpoints such as particulate and dissolved

nutrients inputs to the river system, primary production mechanism in the river and coastal waters,

influx and interaction between river discharge and sea water, and utilization of terrestrial origin mat-

ter by planktonic and benthic organisms. Fig. 3 indicates an example of composition of anthropo-

genic matter, phytoplankton and benthic algae in the particulate organic carbon (POC) collected in

the river between ca. 20 km to 120 km from the river mouth, areas which were not influenced by sea

water. It is notable that phytoplankton production drastically increased in the Ohno dam reservoir at

midstream. In addition, organic matter produced in the forests was not clearly detected showing that

they may be mainly transported during flooding. From early summer to late autumn, sea water enters

into the river from the bottom layer and forms long brackish estuarine zone up to about 20 km from

the river mouth due to low river discharge and increase of sea surface height during this season. In

the river estuary a high primary production layer occurs in the boundary layer between the freshwa-

ter and the sea water where marine phytoplankton utilizes nutrients transported in the freshwater

originally from terrestrial areas (Fig. 4).

In the midstream and downstream benthic animals utilize terrestrial organic matter (carbon),

but from the river mouth to the coastal area benthos primarily use marine products (Fig. 5). How-

ever, the stable isotope CN map suggested the possibility that jellyfish may take phytoplankton and/

or protozoa in the study area. Significant correlation of δ13C between particulate organic matter

(POM) and jellyfish supported that jellyfish is positioned in the food web originated from POM in

this area (Fig. 6). It is likely that the drastic increase of jellyfish biomass relates to an increase of

anthropogenic load including POM supplied by river discharge. We need further research to clarify

the relationship between jellyfish production and nutrients from human activities. In addition to

these studies, several related studies such as the relationship between river water quality and benthic

algal community, ecology of amphidromous shrimps, production ecology of larval and juvenile sea

bass and flounder in the river mouth nursery grounds have been carried out.

Education

In 2005 an approximate total of 18000 man-days were used by visiting staff and students at

FSERC facilities. As research facilities of different fields of mountain forests, plain forests, river and

coastal waters have been bought together, graduate school students can take advantage of a wide

range of research fields. They can expand the scope of their research from a limited ecological unit

to the linkage between several ecological units with an interdisciplinary interest.

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International Symposium on Integrated Coastal Management for Marine Biodiversity in Asia, January 14-15, 2010, Kyoto, Japan

FSERC aims to develop an education program based on field research. We provide a very

unique field research education programs to students, field exercise course on “The Linkage from

Forest to Ocean”. There are three courses, (1) Ashiu Forest - Yura River - Tango Sea in Kyoto, (2)

Kumano Forest - Koza River - Kushimoto Bay in Wakayama, and (3) Shibecha Forest - Bekan-

beushi River - Akkeshi Lake in Hokkaido. In this program students study the structure of forests,

water quality and change of aquatic animal community structure from upstream to downstream/

coastal waters by field observations and samplings (Fig. 7). This field based education program

will also provide us with a lot of field new viewpoints for both education and research.

0% 20% 40% 60% 80% 100%

Offshore

Deep Coast

Shallow Coast

Lower Estuary

Upper Estuary

River POM Macroalgae Benthic Microalgae

Marine POM Estuarine POM

Fig. 5.

Percent composition (%)

of potential food sources

in the diet of benthic

communities.

Fig. 6. The relationship of

δ13C between particulate

organic matter (POM) and

jellyfish in the Tango Sea

and West Maizuru Bay.

Fig. 7. Photos of students at the field research education programs.

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