Urban Nature

diversity in the garden

Why should you cultivate dandelions in sidewalk cracks, spiders in the attic and mushrooms in lawns...

Now that spring has fully arrived, I’m spending time weeding my garden. Volunteer plants have sprung up everywhere, like, well, weeds. I’m not pulling everything out - much to the annoyance of my neighbor who claims my few dandelions are an eyesore even though millions are in the park across the street.

Even in an urban environment (like where I live), we’re still part of nature. Urban living doesn't have to mean surrounding ourselves with a concrete jungle; we can still make room for diversity in nature. Even the dandelion that takes root in a tiny crack in the pavement and the moss that grows on your roof counts as diversity.

Diversity is important because it adds a complexity that makes an ecosystem stable. A single change that destroys one species is not a big deal if many species fill that niche, but a very big deal if it was the only species. For this reason, any ecosystem with only a few species is vulnerable. Consider a lawn containing a single species of grass - soon weeds will move in or nutrients will be used up, forcing the owner to take drastic action like applying herbicides or fancy synthetic fertilizers. Or, consider diversity in relation to our food crops: using a single variety can result in crop failures and no back-up to turn to. A sad example is the potato famine that occurred in Ireland between 1845-1852 (from wikipedia article here). Even though there are many varieties of potatoes on this planet, the Irish only planted a select few species and blight wiped them out - bad, bad news.

A diverse ecosystem, in contrast, acts to buffer the effects of change. No one goes out into an old growth forest and sprays the dandelions (although, exotic plants can still invade). My garden, which I pack full off as many different crops into my tiny yard as I can, will always produce me something.

Taken as a whole, the Earth is an example of a diverse ecosystem and can be considered a biosphere. People have dabbled in creating artificial biospheres since at least Victorian times. On a small scale, you can go out and buy an 'ecosphere' which is a sealed glass ball filled with water. Inside the sphere is a little ecosystem consisting of shrimp, algae and bacteria, which isn’t very diverse. In 1986, Carl Sagan wrote a glowing article about these ecospheres called, 'The world that came in the mail'. Their makers say these glass worlds can last up to 10 years, but critics say the shrimp are slowly being poisoned by their own waste while starving. Perhaps a bigger biosphere is needed.

Biosphere 2 (earth is Biosphere 1) is a 3.14 acre sealed greenhouse in Arizona that is broken up into several different types of ecosystems. Each ecosystem included several species that filled the same ecological niche, and soils were seeded with micro-organisms in an effort to enhance diversity. In the early 90's, an experiment was conducted by sealing in eight volunteers to simulate using a biosphere for space colonization. I remember seeing the ad for volunteers and being fascinated with the idea; however I had other commitments at the time and couldn't apply - which is perhaps for the better.

These eight people to be were sealed into Biosphere 2 for two years where they grew their own food. Their atmosphere was also enclosed, so the only oxygen available came from the plants within the biosphere. It turns out the biosphere wasn't a stable system: carbon dioxide levels fluctuated widely and oxygen levels couldn't be maintained. All the pollinating insects died, while cockroach and ant populations overran the place. The people sealed inside couldn't grow enough produce, forcing them onto calorie restricted diets.

One result of this experiment was to demonstrate that creating a stable biosphere is currently outside our capabilities. Since we haven’t successfully made a new biosphere, Biosphere I is all we have. So don't get rid of all the diversity that pops up or moves in. Keep a little diversity at home.

Aliens for dinner

Not the alien I mean

Sounds like I invited some extraterrestrials over to share a meal but, what I really mean is eating invasive species as a form of revenge against the damage they inflict on our native species.

As people move around, we tend to take critters (and plants - which I’m not going to discuss) with us. Rats and cats have been introduced across the globe, both of which have been known to decimate bird populations - especially on islands where birds have lost their ability to fly. Pigs were deliberately left on tropical islands by passing sailors to provide future food.

Sometimes animals are intentionally introduced as a means to fix a problem. For example, Australian sugar cane crops were being decimated by cane beetles, so in 1935 just over 100 cane toads were introduced to control the cane beetles. The cane toads adapted well to their new environment, now there are over 200 million - however they didn’t control the cane beetles. Instead cane toads caused all sorts of other problems as they are toxic to the animals that try to eat them.

Want to make a buck? 
How about introduce a critter that produces a luxury product, like beaver fur. In 1946, 50 beavers from Canada were introduced to the southern tip of South America for just this reason. It turned out great for the beavers as there were no predators to worry about. The beavers went on to do what beavers do - gnaw down trees and build dams. Unfortunately, the forests in that region can’t handle beaver damage like North American forests can, so the damage is extensive. Active programs are still underway to remove the beavers.

Not all introduced species create these kind of problems, however there is always a risk that a local species will be displaced by the newly arrived animals. The result is a loss to our global biodiversity as our world-wide ecosystem is becoming more and more homogenized.

In my part of the world, we have lots of introduced species (tropical areas often have more - Hawaii and Florida are perhaps the hardest hit with alien invaders). There are green crabs, manila clams, carp, house sparrows and grey squirrels to name a few. Another that has become ubiquitous in North America is the European Starling. These noisy birds like open country - like orchards and grain fields. They often flock together in massive flocks where they scour the area for fruit and insects to eat. They indiscriminately eat crops intended for human consumption which has put them on the hit list of many farmers. They also out compete local birds, for instance swallow species like the purple martin, for nest sites.

Why would anyone introduce starlings? 
In the late 1800’s, Eugene Schieffelin decided to introduce every bird mentioned in Shakespeare's works into North America. As part of this odd plan, 60 starlings were released in 1890 into New York’s central park. Now, there is an estimated population of 200 million.

So what can be done? 
One option is to eat the invaders. I was at an event recently put on by the Penticton Museum and Archives for the opening of the traveling ‘Aliens Among Us’ exhibit created by the Royal BC Museum. The exhibit highlights alien species in BC. At the opening, breaded and fried starling breast was offered - the meat was dark and gamey, reminiscent of goose, and was quite good. For Okanogan fruit growers, eating starlings must be a delicious form of revenge.

It would take a lot of effort to harvest enough starling breast to make a full meal. I’ll just keep the idea in the back of my mind in case there is a zombie apocalypse and starlings are all I can catch.

As a tangent - people are not considered ‘aliens’ in this context because people tend to move themselves around (i.e., natural dispersal) - although governments might label people as aliens for various reasons. By this same logic, extraterrestrial aliens would only be considered aliens if they hitched a ride to earth on a space shuttle instead of their own spaceship.

Plastic in the ocean – a depressing thought

A myctophids (photo by G. Hanke RBCM)

“No scientist would ever use the state of Texas as a unit of measurement” 

       - Captain Charles Moore

My husband and I went to a talk by Captain Charles Moore recently. He wrote 'Plastic Ocean', a book I'll read and write a review of (we have been planning to get the book for some time). He brought up some interesting and depressing points about how much plastic is in our oceans and what it's doing to the life there.

Only about 10% of the garbage that gets into the oceans washes ashore; the rest is concentrated into the mid-ocean gyres. An unfortunate side effect of our convenience-based consumer lifestyle is that much of the garbage produced is plastics, which float and don't breakdown. It takes approximately 6 years for the garbage to travel around a gyre and the average life of the garbage in a gyre is 10 revolutions – that is 60 years.

At first the plastics resemble what they started as – a milk crate, a laundry basket, etc. Since plastic presents a hard substrate, algae eating fishes claim larger chunks as shelter and keep the surface fairly algae free. This clean plastic eventually gets colonized by barnacles and corals creating a new multi-level trashy ecosystem - with algae as the base, then on to herbivores, planktivores, secondary invertebrate consumers, and so on ending at the top predators (large fishes, birds, dolphins and relatives).

As hard-shelled invertebrates grow, their mass overcomes the buoyancy of the plastic. The reef sinks, and over time, the attached organisms decay or dissolve in the cold ocean depths. Buoyant once again, the plastic floats to the surface and the cycle of colonization can begin anew.

In the long run, this plastic garbage will rub up against other debris or be broken by wave action. The plastic pieces get smaller and smaller. A ruby-red bottle cap might be scooped up by an albatross to be fed to its chick or the plastic rings holding a six-pack together might end up around a sea turtle, restricting normal shell growth. Captain Moore mentioned myctophids, an abundant group of lantern fishes which are a vital part of the open ocean food web. Dissections of their stomachs show some of these fish are eating as much plastic as food. Even the tiniest pieces can be ingested by filter feeders.

Plastics are known to absorb pollutants. Species low on the food web eat plastic scraps, creating another way for pollutants to end up in our food. I wonder, what that tuna I ate for lunch ate for its lunch?

So what can we do? I try to use as little as plastic as possible. I have my own metal water bottle and ceramic coffee cup. I keep food in glass containers, and use re-fillable bottles for shampoo and cleaning products. Any other ideas?

as a tangent: thanks to my husband for helping me with this one.

Playing with fire - again

Burning an old bird house

We partly heat our home with wood for reasons including having a fireplace, being given a large quantity of well seasoned firewood and taking down a tree down on our lot. Ours is an actual fireplace (not a wood stove), that is only a chimney modification away from an ancient fire pit – meaning that if we aren't careful our house fills with smoke, which I consider a negative point. On the plus side, having a fireplace means there is always kindling around making me ready for a vampire attack.

The sound and smell of wood fires are nostalgic for me. A whiff of wood smoke transports me back to the house I grew up in and the wood stove that heated it (funny, I don't immediately recall carrying all that wood into the house – yet I did lots of that too). We aren't alone with our fireplace as 20% of Canadians partly heat with wood.

In general, wood is a much better heating source than fossil fuels. For example, natural gas emits 15 times more carbon dioxide per kilogram than wood. Is a wood fire better for the environment than using electric heat (our other option)? The type of wood burned matters in two ways. First, the energy content of wood depends on the variety of tree it came from. Secondly, how dry the wood is. Moisture content determines how firewood burns and how much heat is released. Dry wood produces more heat than green wood of the same species.

Here is a good explanation of why wood might be okay (from here):

… Only a relatively small percentage of electricity is from renewables like hydroelectric dams, and even then there are environmental problems due to flooding large areas. Wind turbines will never produce enough electricity to be used widely for home heating.

Firewood, on the other hand, can be produced with slight environmental impact because it needs little processing and most of it is used close to where the trees grew. Wood is the most economical and accessible of all renewable energy resources for many households and it has value beyond the displacement of fossil fuels and reduction of greenhouse gas emissions. It is practiced on a small scale and the householders that use it gain a better understanding of their impacts on the environment than users of other energy sources. Families who heat their homes with wood responsibly should be recognized for their contribution to a reduction in greenhouse gas emissions and a sustainable energy future.

In a modern context, and knowing what we now know about the environmental impacts of all energy use, wood can be thought of as a ‘new’ energy resource, provided it comes from sustainable sources and is burned in advanced combustion appliances.

The article goes on to make it clear that wood heating isn't for everyone and how it's done is critically important.

An interesting side point – if a truck load of wood spills, it can just be picked up again the only cost is a bit of labour. If a truck load of oil spills it's a whole different problem. Plus, where I live wood can come from near by, while fossil fuels come from far away.

How to be an algivore

powdered chlorella on a spoon

To start my investigation of algae, I cracked open an old textbook of my husband’s titled: ‘Introduction to Phycology'. According to the textbook, “algae is ubiquitous, occurring in practically every habitable environment on earth.” I agree as I don't have to look far to find algae. My aquarium hosts all sorts of algae types resulting in periodic algal blooms, some less desirable than others. Walking into my bathroom, I can often find a pink alga growing on my shower curtain which would take over my shower if I didn’t regularly beat it back with bleach. Further afield, algae can be found thriving under Arctic ice and in deserts. I doubt there’s a more a resilient plant out there.

Plenty of critters thrive on an algae diet. Back to my aquarium, a farlowella (a stick-like fish with a suction-cup-like mouth) thrives on the green alga growing on the glass. My ever-expanding population of snails also dine on this alga. Out in the wild, frog and toad tadpoles live on algae. In fact, algivores reside all over this planet. Plenty of humans include algae in their diets - and have been doing so for eons. Apparently, ancient Aztecs considered spirilina (a freshwater microalga) a staple. Many coastal communities harvest seaweeds (a type of algae) all over the world and have done so for centuries.

In the alga eating spirit, I've decided to try eating (drinking actually) Chlorella vulgaris daily. Chlorella is a microscopic freshwater green algae. I bought a small tub of it in powdered form. Before I opened the tub, I expected chlorella to smell like pond scum, instead I got a pleasant surprise when the smell reminded me of a hayloft on a sunny day (still not a food smell). The powder is a dark forest green, so dark it's almost black, with the texture of a ground up pigment.

my farlowella kindly cleaning the glass for me

It is easy to find glowing reports about chlorella (which I keep wanting to pronounce as cholera) as a superfood. I'm sceptical whenever the declaration of a 'superfood' is made, especially if the superfood was considered a 'staple' of an ancient remote civilization – everyday food never seems to be declared a superfood. Instead of eating a blackberry from my backyard, am I supposed to rush out and buy acacia berries from South American jungles?

There are documented benefits to eating microalgae. First of all, they contain all sorts of nutrients and complete proteins. Additionally, chlorella can reproduce itself four times every twenty-four hours, making it the fastest growing plant on the planet. This productivity is an important factor in considering food sources for our seven billion plus population. As for the health claims, I just don't know. According to the internet, chlorella is apparently a cure-all, especially useful for 'people with poor vitality' (whatever that means). On the flip side, I've found web sites documenting digestive distress caused by consuming chlorella. I take the hype with a grain of salt.

Another well documented benefit to chlorella is how it improves air. Experiments have shown chlorella absorbs carbon dioxide and replenishes oxygen (important for long space voyages). If cultivated in tanks, eight metres squared of exposed surface is needed to keep one person breathing – which isn't much considering the cultivation tanks could be shallow and stacked. These experiments were conducted in soviet-era Russia (1970s) where they made no effort to eat the stuff. NASA took the next step and looked at chlorella as the sole food source for astronauts on long space voyages – apparently they would survive, but I bet they would be grumpy.

As a food, chlorella poses a bit of a problem. It's a single celled spherical alga with tough cell walls. These cell walls make it impossible to digest in its natural state. Processing of some form is required. Chlorella has a second problem – flavour. I've tried algae (in this case seaweeds) that have tasted fantastic, chlorella doesn't. It isn't that it tastes bad exactly, just unfamiliar. So far, I haven't found any reference on how to make it taste good – just advice on masking its flavour in smoothies, or taking it in pill form. I tried it in a chocolate-banana smoothie, the smoothie was fine but there was no hiding the fact that chlorella was in there.

Spider plants

A spider plant inhabits a corner of my home office, in fact I can't remember a time when I didn't have a spider plant somewhere in my home. I poached this particular plant from an off-shoot of a friend's plant and it now has an off-shoot of its own. Based on my reading about spider plants, I think I'll pot up the new off-shoot and create another plant.

Spider plants, or Chlorophytum comosum, originally came from South Africa to become a very common house plant. Their tolerance to some neglect makes spider plants a great plant for busy folks. I don't know what spider plants look like in the wild, but mine is the typical domestic variety with long, spikey green leaves with a white stripe up the middle. I've also seen spider plants with solid green leaves. It isn't my prettiest plant - the tips of the leaves tend to go brown (I hear regular fertilizing can help prevent this) - but what the spider plant does for my indoor air keeps me growing them.

Nicely insulated houses, like mine, can have significantly more polluted air than the outside. In the winter, when windows and doors are kept closed, these air pollutants can build up. Fortunately, cleaning up indoor air has been extensively studied by NASA because an extended space mission can't possibly bring enough air for the whole trip – so the air needs to be cleaned and re-used (the same hold true for water in space).

In a house or office building the most common pollutants include carbon monoxide, formaldehyde and benzene – each comes with its own negative effects. Plants provide an easy, low energy way to remove air pollutants. Since this is not a new idea, a technical term exists – phytoremediation, which is defined as the use of plants to remove environmental pollutants or render them harmless. The most effective plants for dealing with air pollution include: philodendrons, golden pothos, spider plants and chinese evergreens. My spider plant can effectively remove lots of carbon monoxide. Some say a spider plant removes about 560 micrograms per hour of formaldehyde (ref). They go on to say that a spider plant can remove all the formaldehyde in a room in under 4 hours, but, it didn't provide any back up data so I'm suspicious.

More than just the plant does this good work, microbes found in the soil also aid in removing pollutants. To create an optimized plant filter combine the plant and its associated soil microbes with activated carbon* - a combination that is already available commercially.

There is another side though – some argue that plants as air filterers are not that effective in real world rooms (as opposed to controlled conditions in a lab). Plants also increase humidity in a room, which can lead to mold issues if you aren't diligent. I tend to have lots of plants – I enjoy seeing them and believe they improve air quality, although perhaps not as much as some say they do. I think a reasonable additional step is to also avoid adding chemicals to your indoor environment (like cleaning chemicals or particle board furniture) and to air out rooms whenever the weather permits.

*As a tangent – what is activated carbon? It's a small carbon chunk with an extremely rough and porous surface. This creates a huge surface area for the size of the chunk, according to wikipedia: just one gram of activated carbon has a surface area in excess of 500 square meters. This huge surface area is available to bind to pollutants (and other stuff).

Can we come up with a better way?

I've been thinking a lot lately about ways I can reduce my ecological footprint and I have some ideas.

I've been reading 'Water, A Turbulent History' by Stephen Halliday, a book I randomly found in the library. I was looking for books on how to improve my house's energy efficiency in the engineering section and I found a history book. I was intrigued by the title so I signed it out. How he describes water pollution by sewage got me thinking.

In 1357, King Edward III decreed 'no man shall take any manner of rubbish, earth, gravel or dung out of his stables or elsewhere to throw and put the same into rivers Thames or Fleet'. Due to this attitude, up until the early 1800's, the Thames and its tributaries remained reasonably clear of pollution.

In London during these times, human waste was removed by dedicated workers called 'nightsoilmen'. These men carted away the waste at night and sold it to farmers as manure. Apparently, they earned a decent pay for their work. Then things changed for the nightsoilmen. Competition was introduced when bird guano was imported from South America, starting about 1840. The guano was easier to work with for the farmers and had less of a smell. About this time, having a water closet in your home became a status symbol.

Water closets were invented in the 16th century by Sir John Harington, who made two. One of which was given to Queen Elizabeth I. She didn't like it because the loudness of the flushing announced to everyone when she used it. Without a royal stamp of approval, the water closet became a neglected idea until early in the nineteenth century.

When a water closet is flushed there is only a little 'waste' for 10-20 times the volume of water. The nightsoilmen found this wet waste hard to collect and transport and the farmers no longer wanted it. Cesspools now overflowed into the waterway, polluting them. Cholera epidemics followed and ultimately sewer systems were built.

So now what was once composted (and likely still is in many parts of the world) is now diluted with water and washed away through dedicated pipes buried beneath the ground by gas guzzling equipment. Sewage ultimately ends up at a dedicated treatment plant of some sort that no one wants to be a neighbour to. At any point a leak could pollute our water ways and in many places this has happened. There must be a solution for urban dwellers that doesn't require fancy infrastructure or lots of a critical resource such as water. I realize human waste can carry disease, but is watering it down and flushing it away the best way to deal with it?

Bamboo – the grass that can be almost anything.

So what can I toss into a stir-fry, play a tune on, build scaffolding out of or put on a shirt made from? The answer is bamboo – the fastest growing member of the grass family. Right now I have several hand towels made of bamboo and a bag of bamboo shoots in the freezer. I'm debating planting some in my front yard (although it never looks healthy in neighboring yards so I might not) and flooring my house in it. Bamboo sounds like a miracle plant, but like everything it has a downside.

Wikipedia tells me that grasses can be considered the most important plant group. This group includes the grain and cereal crops people cultivate for food, wild grasses eaten by livestock or other animals, as well as bamboo, from which almost anything can be made. Bamboo shoots can be eaten, they are very tasty in a stir fry and they can be fermented into a sweet wine. Like other grasses, when bamboo is harvested it is cut, not dug up, so growing bamboo can add stability to soils and prevent erosion while producing a viable harvest.

Pesticides are not commonly used when cultivating bamboo. There are a few pests out there that like to munch on bamboo (I suppose pandas would be one), but they can be dealt with manually by cutting out the infested stems. Once the bamboo is harvested, pests become more of an issue. To prevent this, some large-scale operations treat the bamboo with a mixture that can include DDT. Dark flecks in the bamboo is often a hint that that bamboo has been treated this way. Once harvested, bamboo needs to cure. There are many ways this is done from soaking in water for months to burning techniques – it can even stored vertically and allowed to dry naturally. So, now the bamboo is ready to go.

Paper could be made through techniques mastered by the Chinese eons ago. Flutes could be made; I love the haunting sound that a bamboo flute can emit – it seems unearthly. Since I have no musical ability, I won't be making my own flute even though many websites exist to tell me how.

Bamboo fiber is becoming more and more available and is often touted as an eco-friendly option. Is it better than other fibers available? The answer is maybe; it depends how it was made. Bamboo can be made into fiber by two methods. The first, eco-friendly option is similar to how flax and hemp fiber is extracted. Stalks are crushed. Then natural enzymes take over breaking the fibers down more. Finally, the fibers can be combed out and used. The second method is essentially the same as how rayon is made from cotton. Harsh and toxic chemicals are used to break down the stalks and mechanical spinners extract the fibers. The label on my hand towels only say they are made from bamboo, not which method was used in the making of them.

If the first method is used, bamboo has a lot going for it. Like other natural fibers it is biodegradable. From the same sized space, bamboo produces ten times more fiber than cotton while requiring significantly less water. A website selling bamboo clothing says that bamboo fabric is soft (which is true of my towels), anti-fungal, anti-static and even cuts out most harmful UV rays. So, if you need a new shirt bamboo produced the right way is a great option. However, I don't recommend you throw out all your cotton shirts and replace them with bamboo - sometimes the most environmentally sensible option is to get the most wear and use out of the things you already have. But when your cotton shirts wear out, go shopping for a naturally prepared, bamboo shirt.