Resilience: Aquatic lives in Yadoriki Water Source Forest, summer 2021 やどりき水源林

In Yokohama, very urban place, a part of megalopolis Tokyo, people play THE major role for messing up the habitat for aquatic creatures, such as dragonfly. In the same prefecture, I mean Kanagawa Prefecture, story can be different. The case in point: Yadoriki Water Source Forest やどりき水源林. There, the protagonist, it seems to me, is in the end Mother Nature. Let me tell you my recent adventure there.

Kanagawa Forest Instructors are doing a guiding service at Yadoriki Water Source Forest. At 10:00 and 13:00 every weekend between March and November, two forest instructors are on duty at Yadoriki admin cottage near the gate. We are showing the forest for visitors. The place has lots of interesting things like vegetation, animals, and geological features that seasonally change. Our guiding is on demand base. If a visitor request to see flowers in season, for example, we guide the person according to the theme. We also have a rough half-day program to suggest if you don’t have a particular idea about Yadoriki Forest (; the calendar is available from here). The themes we offer every month are,

1. General nature experience, aka small hiking
2. Forest relaxation walk
3. A bit of woodcraft experience, and
4. Visiting Forests of Growing (; my post on June 9, 2017)

In addition, we have a special program only for July and August. It’s a small observation session of aquatic creatures.

Actually, this summer-only program is popular. What we do is catching tiny water creatures from Yadoriki Stream and observing them swimming in a tray. After the session, we return the living things to the stream. The educational level of the program is for 4-5 years old, and up. Often parents, not kids, become too involved in and we instructors must do babysitting to ensure the safety of participating babies. Elementary school kids can have a fun day and finish their homework of “independent research over the summer holiday.” Visitors don’t have to bring anything. We instructors bring all the necessary equipment, including pencil and a note. Above all, it’s free! Bargain, don’t you think?

A larva of caddisfly

So, we, Kanagawa Forest Instructors, are watching Yadoriki Stream all year around to make it sure we will have special summer program safely. Meanwhile two mega-typhoons hit the area during September and October of 2019. The feature of Yadoriki Stream was changed radically + there has been some possibility of debris avalanche to the downstream. Luckily or not last year, due to COVID-19 the entire summer program for Yadoriki was cancelled. The prefectural office was busy stabilizing the banks and riverbed of the Stream. In early spring this year, the scenery of the area where kindergarteners once enjoyed their hunt for aquatic creatures was totally different (; my post on March 18). In March, one of my senior Instructors watched bulldozed riverbed and murmured “… how cheerless …” We were worried if we could have aquatic observation session this summer.

Yadoriki stream in spring 2019.
 It was before the monster typhoons …

In fall 2019. Typhoons changed the scenery.

In April 2021.
 The riverbed of Yadoriki Stream was bulldozed.

The major construction works for Yadoriki Stream was completed in April. Since then, there were several mini storms, if not typhoons, for Yadoriki area. When I returned Yadoriki early June, once mechanically excavated river flow was already altered with crumbling banks constructed by bulldozers. Hmmmmmmm … maybe from civil engineers’ point of view it was a depressing scenery. But for us forest instructors, the situation offered a hope for fun observation of aquatic creatures once again with kids. “Let us check 3 points along Yadoriki Stream. One in the mainstream, and the other for two branch valleys.” We entered the water course with nets and buckets. It turned out we were not disappointed.

Whatever the civil engineers intended,
 the artificial riverbanks are crumbling now,
 by just  tiny storms.

Water was still a bit cold. But we could find several nests of caddisfly larva here and there at the bottom of rocks. Lots of small nymph of stonefly came out of our nets. Tadpoles of Buerger’s flog were swimming in small but many pools of warmer water diverted from the stream. Amphibs of several dragonflies and megaloptera were already in certain size, meaning they were eating well as predator of the other smaller aquatic living things. We even found planarian flatworms, in plural.

A planarian flatworm and friends

“Well, it was needless anxiety, in the end.” “Yes. It may be difficult for kindergarteners to enter several spots we’ve checked today. But there are the other corners of the stream we would bring them for observational sessions.” “Indeed. For adults, we may think to prepare some facilities down to the stream.” “That’s a matter of budget.” “Hmmmm …” In any case, weekends of this summer, we forest instructors could guide you for observation fun of aquatic creatures. Thinking such an industrial vista of last March, it is amazing Yadoriki Water Source Forest recovering its natural environment this quick. Don’t underestimate Mother Nature, I presume.

These days,
 many families are having picnic on the Yadoriki Stream.

Oh, by the way, a wild serow may have decided to make Yadoriki Water Source Forest its territory. As we encounter it so many times, it seems to me the animal doesn’t have any problem having lunch next to us humans. Please let it be naturally in peace if you’re lucky enough to see her/him munching grass along the forestry road.

A photo taken not in a zoo

If you find environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121
〒243－0121　厚木市七沢657
Phone: 046-248-0323

You may send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/