Bubbles in forest: …what are these?

 

Around this time of year, i.e. during the monsoon season in Kanagawa Prefecture, when we stroll in a forest, we often meet with bubbles in bushes or branches. If it is in downtown parks, it could be a joke made by kids with soaps. In deep mountains, such mischiefs are unlikely. What are these? Recently, I found at least two origins for them.

One I learned is that bubble, called in English “cuckoo spit,” is a nest for larva of froghopper. These kids (and their parents) eat their meal from xylem of a plant. They insert their hypodermic needle-like mouth to xylem and drink water and bit of amino-acid + minerals the root sends to the upper part of their body. After drinking such water, the larva of froghopper mixes in their body the nutrition-less H2O and their waste products, i.e. ammonium, amino acid and wax ester, and pees it. So, their urine is sticky ammonium soap that can coat the branches of plants. These babies of froghopper have a butt which has a snorkel-like pipe inside. When they are in the pond of their pee, they can still breathe by sticking out the tip of their butt. By doing so, the bug blows the soapy pee, which makes those bubbles. Normally, except for a very specialized species, the predators of kid froghoppers cannot come in the bubbly nest since they cannot breathe inside. The fizzy house is a haven for larvae. We can find so many soapy shrubs in the June forest … there are so many babies inside, I guess. Very luckily so far in Japan, we have not heard outbreak of meadow froghoppers which can bring Xylella fastidiosa inside the xylem. This virus quickly clogs the xylem and the infected vegetation cannot carry nutrition the root sucks from the ground. The plant is killed quickly by starvation. We at least have not had this problem so far …

Lots of bubbly cradles for froghoppers

And since 2020, we forest instructors of Kanagawa are welcomed by another bubble in Yadoriki Water Source Forest やどりき水源林. The foams in water source forest we found are far larger and more solid than that for froghoppers. It is made by real frog, named forest green tree frog. The bubble in Yadoriki is their frogspawn. Historically speaking, the report of finding frogspawn of tree frog is recent phenomenon in Kanagawa Prefecture. People say somebody have brought them in Tanzawa. IUCN defined the frog in LC category so that giving their breeding place in Yadoriki would have certain meaning for biodiversity promotion, I suppose. Adult forest green tree frogs spend their life in boughs of trees in deep forest, but during their mating season they congregate near water, mate, and leave their eggs on a tree branch or something that is above water. The eggs are protected by foams created by parents’ secretion cued by insemination. The eggs are protected by the solid foam during their gestation, and new-born tadpoles stay in the bubble for a while. When it rains, the babies drop down from the foamy cradle to the water below. They then spend their childhood in water until they transform into adult frogs.

Forest green tree frog

So, ideally the water below the bubbly crib of forest green tree frog would be large enough and does not have torrent. In Yadoriki forest such environment is in short supply. The place we forest instructors found with a tree frog bubble was above a concrete gutter with grating lid on a paved forestry road. “Uh-oh. These frogs have real difficulties to find a suitable mating place, I guess.” “Yeah.” “Look, there are another foam pasted on the concrete wall of gutter.” “Isn’t it frogspawn of Schlegel's green tree frog?” “Nah, I don’t think so. They prefer the place nearer to still water, say a shore of a pond, or underground.” “Here, the gutter is dry now. Forest green tree frog does not care much if their frogspawn is washed by water or not.” “Look, here is adult!” Sure enough, on that day around the frogspawns, we’ve found 3 frogs, two strolling the ground below the treetop bubble, and one trapped in a puddle of the gutter whose water level was too low to flow out to Yadoriki Stream. “Hmmmm, they had large suckers on their fingertips.” “Yes, those are the typical fingers for forest green tree frog!” “And they are large. The frogspawn must be that of forest green tree frog.”

Standard location for frogspawn of forest green tree frog

Er … maybe, it’s the situation like
“Ask, and it shall be given to you.”

It’s trapped inside the gutter …
By the way, this one has brown-mottled body.
The appearance of forest green tree frog varies regionally
 from pure green to the one like this.
 From where the ancestor of this came from …?

Apparently, they are struggling to find a suitable place for childcare in Yadoriki and decided to take a compromise. In the small pool where one adult was trapped there were several 2-3cm tadpoles swimming. As we could not find large enough adult aquatic insects in the puddle, the tadpoles are relatively safe with fewer predators, I guess. Yadoriki forest is a water source forest of Kanagawa Prefecture. It rains a lot. During the next rain, that semi-dry gutter will be filled with water and run down to Yadoriki Stream. Adult frog will escape from the trap, but tadpoles may be washed down to the current under open sky. Lots of predators will come … Fingers crossed for the survival of Lightly Concerned species.

An adult and a baby

Someday, trapped frog family could swim there …

Migratory Blue and white flycatcher
has come to Yadoriki water source forest.
 IUCN categorize them LC as forest green tree frog.
In Kanagawa Prefecture, they are defined as “Vulnerable.”
 It seems to me they eat insects but not amphibians
… aren’t they predators for tadpoles and frogs?

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

Forest is Longing for the Sea 1: Garbage, garbage, garbage …

 

There was a shocking news from Kyodo News. On June 5th, a deep-submergence vehicle named Shinkai 6500 of JAMSTEC: Japan Agency for Marine-Earth Science and Technology (海洋研究開発機構), dived into 750m deep of Sagami Bay 相模湾, and found a “sea plateau” pile of plastic garbage. They were identifiable tens of years ago plastic packages of ramen noodles, somebody’s bucket, et al, many of which still held logos and names of food or else. Shocking. The article continued not much was known why they gathered there or how they could (if any) decompose … Sad. Among Niiharu Lovers these days, plastic garbage often becomes a popular idle talk topic. “You see? Now the meat of fishes for our supper contains chemicals oozed out of microplastic in the Ocean.” “Yeah, so does the veggies that absorbs the material from the trashed soil.” “I’ve heard as we’re eating them, more than 70% of our body is already contaminated by old plastics.” Yack. Really?

Sagami Bay

One of the main tasks for weekend volunteering in Niiharu Citizen Forest 新治市民の森 is patrolling the forest for any danger or unsightly scenes preventing us from enjoying the place. We deal with the problem one-by-one. If there is a large tree fallen and blockaded the trekking route, or small landslide is found, we arrange the removal of it either by ourselves or asking the City to hire pro. We also collect trashes when we find any. They are not only ugly, but also pollute the soil with industrial poisons, such as PCB and the other things. Seniors said when the forest became the Citizen Forest in 2000, there still were many illegal damping deliberately concealed in the neglected forest ground. Each time the Lovers pulled out televisions or chairs from the forest, carried them manually to the designated collection point outside the forest, and reported the City to pick them up. After more than 20 years of such activities now it is not so common to encounter such unsocial behavior in Niiharu Citizen Forest. Still, every weekend we pick up plastic bottles of soft drinks or candy wrappers casually thrown away along the forest route. I would say such rubbishes are comparatively easy to deal with. June is the beginning of the season for mowing. We use sickles or motored weed cutters and find plastic or (worse) metallic litter hiding in the bushy grass. They are not only unhygienic, but also dangerous. We must operate our machine carefully not to suffer mechanical kick-back of sharp blade. When a machine runs at the full-speed and hits by unusually hard object like damped metal, the blade could swing unexpectedly, and we may lose the control of the tool. The worst-case scenario is death hit by uncontrolled blade or such hard garbage thrown up by the high-speed spin. It’s depressing to find a shadow of such garbage within grass ...

Here’s the one!

In Miyagi Prefecture 宮城県, there is a famous Non-Profit Organization called “Mori wa Umi no Koibito 森は海の恋人.” The original founders of the group were professional fishermen who nurtured oysters in Kesen’numa Bay 気仙沼. Some 50-60 years ago, their sea was suffering frequent red tide due to discharges from rivers. The fishermen found the origin from which the river carried such contaminated water was degraded forests. The rainwater fallen over the forest went through the polluted ground and amassed the problematic materials when it reached the river. Many tainted rivers poured in the bay and the sea became a damping ground of waste, which became red tide. So, the fishermen started voluntary afforestation in the forests along the rivers that came into their sea. “Mori wa Umi no Koibito” means “The forest is longing for the sea, the sea is longing for the forest.” Their activity has become a sort of national movement in Japan. Thanks to them, we somehow know when we have garbaged forest, the sea near the forest is also full of junk. Niiharu Citizen Forest is located at the edge of the tributary of Tsurumi River 鶴見川 that pours into Tokyo Bay. The plastics and their chemicals from our forest will eventually end up in Tokyo Bay, and beyond. Lovers of Niiharu is collecting the garbage every weekend. We are longed …

Last Saturday morning, I joined a garbage collection activity at Katase Higashi-hama Beach 片瀬東浜, at the opposite side of Enoshima Yacht Harbor, the venue of the last year's Olympics Sailing Competition (; my post on July 30, 2021). For these 15 or so years I join such activity at least once a year in somewhere along the Shonan Beach 湘南海岸. I had an impression the situation was improving as we were collecting smaller pile of trashes from year to year … Yeah, those trashes would not come from Niiharu. For example, the river ends up at Katase Beach 片瀬海岸 is Sakai River 境川 (my post on January 28, 2022). In any case, smaller garbage bags after beach cleaning were somehow comforting. Then, here came the article of piles of plastics at the bottom of Sagami Bay. I had a renewed motivation for beach combing. Actually, I found more complicated things.

Katase-higashi-hama, last Saturday

True, there were not many large garbage on beach. When we collected only such litter our trash bag continued to be light. But there were too many unusually colored dots in sand. They were plastic colors of bright red, blue, green, yellow, ... Lots of seaweeds washed up on the shore. In their tangled fronds, there were many string-like inorganic materials, probably the remnants of fishing nets, fishlines, plastic ribbons, or decomposing supermarket plastic bags. I first tried to untangle them from natural sands and seaweeds, and soon frustrated. My garbage bag ended up with piles of seaweeds cum plastics and sands with microplastics. They were wet and heavy. I dragged them to the designated garbage collection point and felt helpless. Yeah, we are collecting apparently visible plastic bottles and trashes in the forest, but now the old, or new, plastic rubbish changed their apparition that could easily reject easy way of garbage collection. The situation must be very serious now even in seemingly “clean” Japanese forests ...

What are those colored “sands”?

Here, here, and here …

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

Regeneration in Water: Aquatic habitat for Yadoriki Stream, early summer 2022

 

In 2019, Kanagawa Prefecture was hit by two monster typhoons, Faxai and Hagibis. Yadoriki Water Source Forest やどりき水源林 met devastation (; my post on November 1, 2019). Yadoriki Stream overflowed, and the feature of the river changed completely. Last year, I reported you we forest instructors found some recovery from the natural disaster in the forest, including water creatures. This year, we’ve found the aquatic lives in Yadoriki Stream seem to have started to thrive!

Just before the Prefecture entered the monsoon season, we donned long boots and collected aquatic organisms from Yadoriki Stream running the Water Source Forest. We had a bumper crop. Here’s a part of what we’ve found:

Lots of lots of tadpoles of Kajika frog.

Three larva amigos of Kamimuria quadrata.

Larva probably for Perissoneura Paradoxa. The gravelito next to it was its under-construction house. They build a “stone” house and spend their childhood with it.

Actually, there were many larvae of Epeorus latifolium. This creature is one of the indicator species for Japanese rivers, defined by the Ministry of Land, Infrastructure, Transport and Tourism, to measure the level of pollution. When we can find them, the river is VERY clean!

Speaking of the quality of water and indicator species, we’ve found lots of Planarian Flatworms. They cannot survive in polluted water. And they need the water to be cold enough. So, Yadoriki Forest is recovering as a good water source forest!

Oyamia gibba. Hmmmmmmm … it has really impressive “full-body” tattoo …

It has been 3 years since the typhoons destroyed the Water Source Forest. And now, the habitat shows evident recovery. Of course, after the natural disturbance nothing will return as before. And here must be some effect of global warming … Yet, I was a sort of impressed by witnessing suppleness of Mother Nature. Inshallah.

This year,
we’ll have lots of flowers of Alagium platanifolium in Yadoriki.

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

Wishing to be a multilingual, a sort of, or the “dawn” of Biolinguistics (really)

Early last month, I had a chance to have a personal lesson with one of the rangers from the Wild Bird Society of Japan. They are keepers of Yokohama Nature Sanctuary 横浜自然観察の森 (; my post on January 22, 2016) and has done continuous survey of the place, especially for birds. The day was for one of the two regular line censuses per month. They very kindly allowed me to learn their way of doing on site. The route of the research is the same for these 30 years in the Nature Sanctuary. It makes possible for the Society to trace long-term changes of bird life in the South Forest of Yokohama. That early morning, very quietly I walked with Mr. Nakazawa for Wild Bird Society. We each carried binocular, recording forms and a map of the census route. First, we record the date, weather, humidity, etc., before starting the research, and wrote down the time when we began walking. All are vital info for the study … It’s a slow 1.5 hours walk, like 1-2km /h. The way for the research goes like this:

(1) Listen carefully the voice of birds coming within 50m radius of a researcher, I mean,

(2) Make it certain from where that voice comes, North, South, East, West, high, low, etc.

(3) Identify the species of the voice.

(4) If possible, use binocular to identify visibly the holder of the voice.

(5) Record the place and time we find the bird, then jot down species, number of individual, and if possible, male, female, adult, kids, what it was/they were doing etc.

After returning to the visitor center, we summarized our result in a standardized spreadsheet that makes further research easier. Mr. Nakazawa said “In this way, we accumulate the data and study the results several times a year. It can help to update our policy for nature conservation movement.” Indeed.

Early morning in May for Yokohama Nature Sanctuary

It was a very thrilling experience, but difficult one. Inside the forest was dark and birds were moving very quickly from bough to bough. At least for me, seldom came a chance to use a powerful binocular the Society kindly lent me. The main way to find a bird was by listening. Mr. Nakazawa said “Japanese tit has really many voices and ways to sing or call. So do the other birds. The only way to improve the identification is learning-by-doing. Let’s listen …” OK. We recorded not only tits, but crows, herons, swallows, brown-headed thrushes, brown-eared bulbul, woodpeckers, etc. etc. Since then, I became a sort of sensitive for bird voices. I even woke up at 4:30 when a Chinese hwamei declared its territory victoriously in our garden. What, what, what is it this early!!!?????

Actually, since last January it became a secret boom among some Kanagawa Forest Instructors intently listening bird “songs.” The beginning was a TV, called Science Zero series of NHK. On December 6th, 2021, they aired a special for the research by Dr. Toshitaka Suzuki of Kyoto University. He discovered Japanese tits have language with grammar. For example, according to Dr. Suzuki piercing JAAA JAAA screech of Japanese tits are emergency warning among them when they saw their predator … He published his research in Nature Communications, Current Biology, PNAS, Philosophical Transactions of the Royal Society B, etc. The tele was exciting, and we talked about it for months. A senior instructor actually did a mini-experiment as Dr. Suzuki. “You see? I was busy cleaning up bamboo forest and laid around the ropes over the ground to tie up the thinned bamboo branches. Then I noticed a tit was screeching ‘JAAAAA, JAAAA, JAAA.’ Soon the other Japanese tits gathered around me and started huge chorus of JAAAA! They mistook straw ropes for snakes and alerted each other their perceived danger. So, I pranked on them by coiling the ropes around the bamboos. Normally silent bamboo forest became a heavy metal concert!”

Naomi is a peace-loving person. I haven’t done such mischief for jumpy tits. Then, one early morning, I washed my forestry belt covered by dust and hung it on the backrest of a chair in the garden. I then returned kitchen for breakfast. Over my coffee, I noticed normally serene morning garden turned noisy with JAAA JAAA voices of Japanese tits. I returned in the garden and found out tits were surrounding the belt from the roofs. Oh, sorry. It’s a bit rude way of arranging a garden … Sure, tits are talking each other. Can we be multilingual to understand their chat, just like Dr. Dolittle?

It’s not a snake.

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