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/

Here Be Dragons: Dragonflies in Yokohama

Japan is an archipelago of dragonflies. The number of dragonflies identified here so far is 214. Compared to this, number of scientifically counted dragonfly species is 54 for UK, and 117 for the EU. You’ve got the idea, right? Actually, just about 70 or 80 years ago, dragonflies were found en masse in the area of JR Shinjuku Station, aka the downtown Tokyo. In misty eyes, elderly Tokyonites spoke their sweet memory of childhood, like, “You know, after school, we sneaked in the parade ground of the army in Shinjuku to hunt for dragonflies. It was so easy to catch them by Buri.” Buri? “Yeah. Pick two small stones and tie them with thread. That’s Buri. It’s like a delicate rope with weights in both sides. We threw it high in the flock of dragonflies. The thread dangled at least one dragonfly and the catch fell down to the ground. It’s difficult for the first graders to throw Buri that high. The elder kids always dominated the game …” Oh … it’s difficult now to imagine such scenery when we stand in front of skyscrapers, including Tokyo City Hall …

Orthetrum melania

Many Japanese dragonflies has their type locality here in Yokohama. It’s because Yokohama was the first large international port for Japan. The beginning was the middle of the 19th century, the time when Darwin adventured all over the globe. Many naturalists from Europe disembarked at Yokohama to enter Japan, with their insect nets. They found yet very pastoral scenery next to their hotels. Lots of dragonflies flew about above their head. I imagine if we came in such environment from the region of 117 species, every morning must have been a thrilling fiesta. They enthusiastically identified their catches to put Latin names.

Female Lyriothemis pachygastra,
 along Umeda River near Niiharu Citizen Forest
新治市民の森

Those were the days. Now, Yokohama is the second largest city in Japan. Very urban. Rice paddies once comfy home for dragonfly larva were gone. Small streams for another kind of larva become culvert to secure more space for human activity. The number of adult dragonflies inevitably dwindles. American bullfrog and Louisiana crawfish both of which were imported after the World War II to be possible foods for humans, and Pond slider that was brought in to be sold as pets, are multiplied in Yokohama’s water. They are predators for dragonfly babies. Finally, new types of neonicotinoid pesticides, allowed for usage from 2000, are killing off aquatic insects. Many dragonfly species were extinct in Yokohama, even if their registered type locality was Yokohama. Well, there is more, not only urbanization that affected life of dragonflies in Yokohama, according to Mr. Takashi Umeda 梅田孝, dragonfly expert for the Children’s Botanical Garden of Yokohama (; my post on November 4, 2016).

 

Dragonflies are delicate. Their population wildly fluctuates with environmental change. In the process of urbanization, rice paddies in Yokohama were first abandoned for cultivation. It allowed the dragonflies living in wet land to multiply for a while. Rice paddies are inherently artificial landscape where farmers control water flow. Yeah, if the original place was a wetland, abandoned rice paddies return to abandoned wetland. If paddies had water by human intervention, once they are abandoned, the place eventually returns to dry land. From rice paddies to abandoned dryland was a typical story for Yokohama. In dry former-paddies, nymphs for dragonflies cannot survive. The explosion of dragonfly population can end up with rapid extinction. Mr. Umeda who’s researching the ecosystem for dragonflies pointed out Sympetrum parvulum and Libellula quadrimaculata asahinai Selys were such species of tragic story. They became so ubiquitous during the 1980s and the 1990s. But now, they are gone. For Yokohama, there are so many other dragonfly species which are probably on the verge of extinction because the environment of rice paddies is abandoned, if not bulldozed for urbanization …

Beautiful Calopteryx atrata,
which is getting rarer and rarer in Yokohama …

Mr. Umeda said these days we can also find several tropical dragonflies in Yokohama. You may think “Ah-ha, that’s due to Global Warming!” Er, yes, and no. The ability to fly for some dragonflies is indeed phenomenal. They can move around between continents. Some dragonflies in Yokohama, like Ictinogomphus pertinax or Aciagion migratum, are considered gradually flying to the north as the climate change continues. But most tropical dragonflies identified in Yokohama are not natural travelers. Why are they here? Mr. Umeda explained that’s the story of another unintended consequences. Until some 10 years or so ago, it was fashionable for urban schools and parks to create biotopes. The purpose at that time was to provide place of education for sustainable development for city kids whose life is cut off from waterfront with aquatic lives. Good adults thought if there was no place for human kids to experience nature, money could buy it for their school backyard. Many elementary schools in Japanese cities landscaped their school garden with a man-made pond completed with transferred aquatic vegetation. Often, they were transplanted from warmer area of the planet. They carried soil from their homeland, containing eggs and seeds of foreign species. Eggs of tropical dragonflies were such new settlers. Kids of tropical dragonflies were brought from their original home without any intention to come to Yokohama. “You know? So, we are getting familiar with Ceriagrion auranticum ryukyuanum, Lestes japonicus, etc.” In a similar context, Mr. Umeda has a reservation about releasing fireflies for tourism purpose. “Well, to make fireflies happy, the event holders eventually release freshwater snails and vegetable scraps for feeding nymphs of the bug. They would start feeding carps that provide nitrogen and phosphorus from their feces. Yeah, such minerals could be good for increasing phytoplankton that are food for water snails. But, in the end, what would happen for the original ecosystem of the place? Is it a sustainable way to manage greenery?”

Sympetram risi risi

Well, humans could wreck a havoc for natural environment even with good intentions. But we can be not-so-much a troublemaker sometimes. Scientifically well-thought of maintenance job for Yokohama’s greenery could restore the eco-system gradually. Once Futatsu-ike 二ッ池, a large pond next to Shishigaya Citizen Forest 獅子ヶ谷市民の森 (; my post on June 12, 2015), was a garbage water bath because of illegal dumping. Locals, police, and the city office cleaned up the place, and now it’s a nice pond with lots of southern cattail (Typha domingensis). The last sighting for dragonfly Aeschnophlebia longistigma in Yokohama was in 1936, but they were identified once again in Futatsu-ike in 2006. These days we can find Atrocalopteryx atrata very easily in Yokohama’s water ways. During the 1960s and 70s they were considered for extinction. Now, because aquatic vegetation is returning to Yokohama’s rivers, the environment for their home is recovering and the population of Atrocalopteryx atrata is getting larger.

Futatsu-ike, early spring

And so, one day this May, Mr. Umeda called a session with us forest volunteers in the Children’s Botanical Garden to teach sustainable way to maintain aquatic environment in Yokohama. He said “Dragonflies need continuous environment. Open water surface is crucial for female dragonflies to lay eggs. Water must be clean enough for nurturing larva. Then, for dragonflies to emerge from water, they need not so tall grass along the waterway or around the pond. While some male dragonflies declare territory over certain size of open water, female dragonflies often prefer resting in a bush next to open dry space. Or, the other species spend their entire adult life within the aquatic bush of reed. They require a delicate balance between water and dryland. Our mission is to maintain such equilibrium.” Hm, OK. “So, for example, this mulberry tree is spreading its bough over the stream. It hides the water surface from the eyes of dragonflies flying above 10 to 30m high. We cut it down!” He thinned that mulberry without hesitation. Well, it’s ubiquitous mulberry … (; my post on May 28, 2021).

This mulberry must go.

“Now, look at chameleon plants, sasa bamboos, and Japanese sweet flags, along the waterway.” “Weren’t sweet flags intentionally planted here by professional landscapers?” Mr. Umeda replied. “Yes, indeed. And that’s a huge mistake of yesteryears. These glasses accelerate aridification of swampy waterside. When they wither, they add riverbed more organic matter which can eventually make the place very muddy. Water creatures often dwell in riverbed made of so-so gravelly sands and mud. The composition is very important for them to breath. Too muddy, they will suffocate. At the end of the day water flow itself is overwhelmed by the plants and dies down. No place remains for dragonfly larva to survive. The destruction of aquatic ecosystem, you know? To stop it, we need to mow them, or preferably root them out!” So, we donned long rubber boots and ventured in the stream of Children’s Recreation Park. It was a small place. The work itself was not much, to be frank. Though, as it is a popular garden, so many visitors passed by. They saw us in surprise, or sometimes with eyes of horrors. “Are you destroying the garden?” For each question, Mr. Umeda explained patiently keeping the environment sustainable is not leaving it but adding proper human intervention … Hmmmmmm. In the end, to make a place happy for dragonflies rests on the unwearied communication … Thanks to Mr. Umeda’s endeavor, dragonflies, including some rare species, of Children’s Garden and Park are maintaining their population. He is also presiding educational classes at Children’s Botanical Garden for kids and adults who love insects. If you’re interested in it, please check the calendar here.

This is the site to be cleared.

This is the runner of Japanese sweet flags to be removed.

After our work done.

Sympetrum eroticum

Yokohama Children’s Recreation Park　横浜児童遊園地
https://www.hama-midorinokyokai.or.jp/park/jidoyuen/
Yokohama Children’s Botanical Garden　横浜こども植物園
https://www.hama-midorinokyokai.or.jp/kodomo/

213 Karibacho, Hodogaya-ku, Yokohama, 240-0025

Phone: 045-741-1015

Magical Lantern: Campanula punctata

In Yokohama every early summer, around the beginning of rainy season in June, bell-shaped flowers come to bloom along pedestrian ways of greenery. It’s Campanula punctata. I would say they are ubiquitous this time of year. The flower could be one of the first species Japanese kindergarten kids remember their name. At least I think I was one of such babies. They have a very peculiar shape. They have several colors like hydrangea. They have not-so-small flowers. They are easy to learn for novices, you know? They simply are a part of early summer landscape in Yokohama.

During a casual stroll around north forests of Yokohama, we can find many Campanula punctata. Though, once we dive into deeper areas of forest, they disappear, it seems to me. They love sun light, or they may prefer flowering near humans. 😊 Scientifically Japan has known 5 species of Campanula each of which lives in a particular area. “Campanula punctata Lam. var. hondoensis (Kitam.) Ohwi is for more mountainous areas,” etc. I think Yokohama’s is Campanula punctata, but they can change their color along just 50m or so long road. 5m from very deep purple wild Campanula, we encounter white bunch of flowers, and so on. A quick Google search suggests it’s due to very microclimate, such as of soil moisture, of chemical composition of the ground, and the amount of sun light the particular point would receive. It’s something of natural wonder even in very urban environment … Babies love it, naturally.

This and the next are flowering almost side-by-side,
 about 1m apart.

Campanula punctata has several Japanese names. Here in Kanagawa, we call it Hotaru-bukuro ホタルブクロ, meaning “a sachet for firefly.” The season when Campanula flowers appear is the time for fireflies emerge for elegant mating dance. When Japanese field was mainly for rice cultivation, admiring dreamy evening lights of fireflies was seasonal tradition in villages. Kids caught fireflies, kept one bug each in a Campanula flower, and secured the opening with spindly leaves of pine. While they returned home in dark country road, the Campanula punctata could be a petit lantern with magical lights of firefly. One of my senior forest instructors, who presides a nature school for kids in Hakone 箱根, told me when they can have lots of firefly kids can enjoy this traditional game, but “It becomes once in several years adventure these days, you know.” Oh … even in a National Park. One popular solution for such environmental change has been “Buy hundreds of commercial larva of firefly and release them in a stream to prepare for seasonal tourists attraction!” Hmmmm … Though the things have started to change, which is the topic for the next week. Please stay tuned. 😉

By the way, annual firefly season in the forests of north Yokohama is now ending. If it is a normal year, Shikinomori Park 四季の森公園 (my post on June 26, 2020) would hold “Firefly Festival” in the first week or so of June. The event is popular with lots of visitors from all over Metropolis Tokyo. COVID-19 has stopped the fun for these two consecutive years … Can we recover it next year? … In any case, fireflies along Umeda River 梅田川, including in Niiharu 新治, have been fine, COVID or not. 😊

If you find a problem in the greenery of north-half of Yokohama, please make a contact with

Office for the Park Greeneries in the North
北部公園緑地事務所
Yokohama Municipal Government Creative Environment Policy Bureau
横浜市環境創造局
Phone: 045-311-2016
FAX: 045-316-8420

COVID testing!

Er, today’s topic is completely off from the theme of this blog, but I WANT TO tell you. Naomi has got a chance to do COVID-19 testing, not because I felt sick. As you may know, Japan is impressively behind the G7 trend for testing and vaccinating against COVID. The authority is really, truly, under the huge pressure to do something. (Er, just for convenience, let’s leave the performance of the PM or people of such position, for now). One day, I chatted with a person from the City of Yokohama. He was stressed out dealing with so many “comments” about city’s deed for the matter. “Yes, we honestly understand the concern of the people of Yokohama. We’re also citizen of Yokohama facing exactly the same worry of COVID. But we’re only human and a day has simply 24 hours. We need to sleep, you know? Those who SNS about us may sit in a comfy room with enough air circulation. We, every day, are sorting out the crowd visiting the city hall due to the pandemic. Some of them even don’t bother wearing masks. Who’s in riskier situation!?” Poor guys. Oh, by the way, he’s also a forest volunteer entering one of Yokohama’s Citizen Forests every weekend. Especially now forests are his refuge, I guess.

Naomi still doesn’t know the schedule for vaccination of our age group. I think I am careful not to contract the disease … the uneasiness remains. Then, one day, I happened to pass by the main entrance for Sogo Department Store in Yokohama Station. A long line of desks was dealing with a queue. What is it? I wonder. “We’re giving COVID-testing service for free! Are you interested in?” Oh YES, of course! So, I registered myself at Android application HELPO provided by Cabinet Secretariat and Kanagawa Prefecture and received a testing kit. The first thing for the next morning, I collected my saliva (it required A LOT) and sent it to a designated labo for testing.

It was just a couple of days ago. I haven’t received the result yet ... I keep crossing my fingers seriously … Will we have Olympics and Paralympics …? A short notice. Naomi will be a field cast (Olympics/Paralympics volunteer) this summer as a NOC/NPC assistant serving for the athletes coming to Japan ... I don’t know yet to which country I’ll be assigned. I don’t think during the Games I can visit a forest to tell my adventure. I’m now accumulating the draft of posts for this blog as much as possible. This summer my post will report you my experience this spring, and there will be several weeks I cannot update my post. I appreciate your understanding … All depend on the Japanese situation with COVID-19, though ...

If you find a problem in the greenery of north-half of Yokohama, please make a contact with

Office for the Park Greeneries in the North
北部公園緑地事務所
Yokohama Municipal Government Creative Environment Policy Bureau
横浜市環境創造局
Phone: 045-311-2016
FAX: 045-316-8420

Niiharu Administrative Office / Satoyama Exchange Center
新治管理事務所・里山交流センター
Phone: 045-931-4947
Fax: 045-937-0898
Email: info@niiharu.jp
http://www.niiharu.jp/