Tag Archives: urban ecology

2021 garden retrospective

Here are a few random thoughts on this year’s growing season. We had our first below-freezing temperatures here in my Philadelphia neighborhood around November 20, which is 3 or so weeks later than “average” (although I’m not sure if what is reported is really the average, or something like a 30% probability to improve the odds a bit for farmers.)

I got my son a Venus fly trap for his birthday in May. They are native to the Carolinas, which is cool, although I bought this one from California Carnivores. We looked at it for awhile, then left it in our buggy backyard for the summer where it seemed to be very, very happy. It even flowered – now a Venus fly trap flower is not a particularly breathtaking flower, but I was excited nonetheless. Most of the time, there was plenty of rain to keep it wet, but I invested in a gallon of distilled water to top it up occasionally. As I write this in early December, I’ve brought it inside for the winter. I’ll continue to give it distilled water, and no matter how sad or even dead it starts to look, I’ll keep watering it and put it back out in the spring. I threw one away a few years ago thinking it was dead, and was horrified to read later that they naturally go dormant in the winter. They can also supposedly handle some light freezes (again, think Carolinas) but not an extended deep freeze, so it seemed safest to just bring it in. My research said to put it in an “unheated garage or entryway” for the winter, but my urban home has neither of these things.

a fuzzy photo of a Venus Fly Trap flower

The “dwarf” (advertised as 15-feet but 20+ feet tall and maybe still growing) Asian pear tree grew lots of pears this years, which the squirrels really enjoyed. I picked and ate one unripe one just to get something, but there were no ripe ones left when the squirrels were done with them. The annoying thing is that they don’t actually eat all that fruit, they take a bite or two out of each one and drop the rest on the ground to rot. Luckily, I find squirrel antics fairly amusing and my family is not starving as a result of the fruit they are depriving us of.

On the first day of Christmas, my true love sent to me…a squirrel in an Asian pear tree

The Asian persimmon tree grew exactly one persimmon this year. This tree is a bit younger (4 years?) so hopefully there is more to come. The squirrels didn’t eat it – maybe they just don’t know what it is – and it was delicious. I thought I had a photo but can’t seem to find one. I believe persimmons are the most delicious fruit that most Americans have never tried. And I don’t know why – the trees are compact, prolific, pest and disease free (the flip side of this is they probably don’t have much ecological value locally), cold tolerant (there are several Japanese varieties), and the fruit is absolutely mouth watering and yet very tough on the outside which seems like it would make for easy shipping. There are native American varieties, but be warned these grow into very big trees which is why I chose the Asian variety. By the way, I am generally partial to native species, but I have not found the right native tree species that works in my small urban garden. I want trees that provide a little bit of shade for the front of the house but leave sunny areas to grow other things, and that I can easily get under or around. My basic principle is that a plant should have at least one other function, whether an ecological function or a food function, other than just looking good. Of course, plants that have all these things are awesome! But like I said, I haven’t identified the perfect tree yet that fits that bill.

Around July, my garden was clear cut (other than the trees) by a gardener hired by a neighbor. And not just mowed, but scraped absolutely to the ground. I was upset, but it was actually kind of interesting to watch how it responded. It’s a perennial garden, so it mostly grew back quickly. More aggressive and resilient plants outcompeted the less aggressive ones for the most part. Interestingly, some plants that are normally aggressive, like Black Eyed Susan, were probably about to flower when they were whacked and apparently decided they were done for the year. I assume their roots are fine and they will be back. Wild strawberries by contrast loved being mowed and took over an entire corner of the garden. There is way too much lemon balm now, even though I like lemon balm. A neighbor actually bought me some native plant seedlings after it happened, which I found really touching. So now I have an aromatic Aster and a Hubricht’s Blue Star in my garden.

After the garden was clear cut, I talked to the neighbor that (inadvertently) did it, and we agreed that I would just take over part of her garden from now on. To get things going quickly, I’ve picked a prairie seed mix (most “prairie” plants are native to the entire U.S. east of the Rockies). I’ve put down some cardboard to suppress weeds from growing back, put a mix of homemade and store-bought compost on top of that, and plan to sprinkle the seeds over the winter and see what happens in the spring. The only issue is that at least one cat has decided this bare soil makes a nice litter box. I intended to plant a fall cover crop but work, family, and life intervened to prevent that project.

Each year, I like to pick a “try again” species and a “new species”. The try again species is usually something I have tried to start from seed in a previous year without success, and still have seeds left over in my basement. This year, I finally got a sea kale seedling going. Squirrels dug it up multiple times for some reason, and it seemed to wilt during a fall heat wave, but now as we enter December it looks incredibly happy and has even flowered. We’ll see what happens. My “new species” was goldenrod variety “Golden Fleece”. I got it from a nursery out west somewhere, but the variety was originally bred at the Mount Cuba center in Delaware, which is nearby where I live and on my list of places to eventually go. It is advertised as a ground cover less than 18″ high. It is flowering and looks happy out there.

In pots, I did cherry tomatoes, Thai basil (both the “holy” variety as Indian people tend to refer to it, which Thai people insist is just “normal” Thai basil, and the “sweet” variety as Thai people refer to it, which seed companies in the U.S. consider normal Thai basil.) Both taste and smell awesome, and are much more heat and drought tolerant than Italian basil, which tends to wilt and die on me if I go away on a summer weekend. I also tried a mini-version of a polyculture mentioned in the book “Gaia’s garden”, which was fun although it didn’t really go as planned.

this year’s pots

We had a groundhog. Not exactly a rare species, but a rare siting around our urban neighborhood so fairly exciting.

a furry friend

And finally, I loved this enormous sunchoke. It was not in my garden, but was likely spread by an enterprising squirrel from my garden to a neighbor’s garden, and then forgotten. I read The Dark Tower this summer, in which God is at least sometimes embodied as a rose bush. But I am not a big rose fan. If I were any sort of deity, I might choose to be a sunchoke.

an enormous sunchoke

wolves create a landscape of fear!

The “landscape of fear” is a thing in ecology where predators control prey behavior just by making them afraid of predation. This article compares the cost of wolf predation of livestock to the money saved when wolves keep deer away from highways. The comparison is overwhelmingly in favor of leaving the wolves to keep deer from the highways, even if they eat a few sheep.

Wolves make roadways safer, generating large economic returns to predator conservation

Recent studies uncover cascading ecological effects resulting from removing and reintroducing predators into a landscape, but little is known about effects on human lives and property. We quantify the effects of restoring wolf populations by evaluating their influence on deer–vehicle collisions (DVCs) in Wisconsin. We show that, for the average county, wolf entry reduced DVCs by 24%, yielding an economic benefit that is 63 times greater than the costs of verified wolf predation on livestock. Most of the reduction is due to a behavioral response of deer to wolves rather than through a deer population decline from wolf predation. This finding supports ecological research emphasizing the role of predators in creating a “landscape of fear.” It suggests wolves control economic damages from overabundant deer in ways that human deer hunters cannot.

PNAS

So in a rational world you would maybe take a small fraction of gas tax or toll payments and use it to compensate the farmers for their sheep, in exchange for the farmers not going after the wolves. Or you could just make it illegal to go after the wolves and try to enforce that law. Or some combination. What makes this sort of thing tough in the real world is that a small group impacted by a policy can organize and get political attention, whereas some nebulous idea of “society as a whole” is not going to organize, understand the issue, and lobby the politicians. You could maybe imagine insurance companies representing car owners and truckers getting involved in this issue, if the savings are really so dramatic.

How much ecological function can urban green space provide?

This is an important research question, I think, as the world becomes even more urbanized. Here’s a new study:

Vegetation Type and Age Matter: How to Optimize the Provision of Ecosystem Services in Urban Parks

As cities grow, urban greenspace assumes a more central role in the provision of ecosystem services (ESS). Many ecosystem services depend on the interactions of soil-plant systems, with the quantity and quality of services affected by plant type and age. The question, however, remains whether urban greenspace can be included in the same ecological framework as non-urban greenspace. Our previous studies have contributed towards filling this knowledge gap by investigating the effects of plant functional type (evergreen trees, deciduous trees and lawn) and plant age on soil characteristics and functionality in urban greenspace, offering also a comparison with non-urban greenspace. A total of 41 urban parks and five non-urban forest sites within and adjacent to the cities of Helsinki and Lahti (Finland) were included in this project. Path analyses presented in this contribution, combined with a synthesis of previous findings, offer strong evidence that urban greenspace functions similarly to non-urban greenspace. In particular, plant functional types lead to soil environmental modifications similar to those in non-urban ecosystems. Therefore, vegetation choice upon park construction/implementation can improve the quality and quantity of ESS provided by urban greenspace. However, although vegetation modifies urban greenspace soils with time in a fashion similar to non-urban greenspace, the vegetation type effect is greater in non-urban greenspaces. To conclude, our synthesis of previous studies provides science-based guidance for urban planners who aim to optimize ESS in urban greenspaces.

Urban Forestry and Urban Greening

Ecosystem services and ecological function are not exactly the same thing. Ecological function just is. Ecosystem services are what ecological functions do for people, and fit into the mainstream economic analysis framework. Part of the issue in studying this, I think, is scale. If you look only at one site, block, or park in a city, you might conclude that ecosystems services are negligible or un-measurable. If you look at the entire network and how it is connected, you might conclude that the effects are measurable and that there are policy and design choices that could make them better.

Biodiversity is something else again. More biodiversity is not always better, if it consists of more species of rats or coronaviruses, for example. But biodiversity may be a reasonable proxy measure for how the structure of a designed urban ecosystem translates to ecological function. This is useful if ecological function itself turns out to be difficult to measure. And I think the most useful measures might be biodiversity of animals such as insects (bees, butterflies) and birds. Because the plants in urban areas are mostly the ones that people put there. Biodiversity of plants can be improved through design choices, which is a good thing but in measuring that you are largely measuring inputs to the system rather than the resulting state of the system. Measure the animals, and you are measuring the resulting state of the system.

Measuring things that flit and flutter around might seem daunting. Well, you could try to do it with cameras and image processing of some sort. Or if you are interested in insects you can focus on larva, aka caterpillars. Tracking down bee and wasp nests seems a bit more risky, and you might also have a public relations problem trying to explain why more bee and wasp nests would be a good thing. But caterpillars don’t move fast, so trained people should be able to cordon off an area and find and identify them periodically. Let’s say you did this once a week for a year at several defined points in an urban area, especially if land use changes are occurring (or maybe some places they are occurring and some places they are not occurring.) Doing the same thing in nearby forests and/or farm fields might also add worthwhile data. Now you can do some data analysis and modeling, and maybe figure out design or policy choices that would help the little critters while also benefiting or at least not pissing off people or costing them any money. If you want to fund my half-baked research proposal, let me know.

what is green infrastructure

Here’s a paper that goes into the many definitions of green infrastructure across different disciplines, along with related concepts. I’ve certainly seen narrow definitions used in my own discipline of water resources engineering. Defining clearly what you mean by a term and sticking to that definition is actually a good thing, because it takes the power out of the words in the definition itself, and you are now defining the actual structure and/or function of something, and you can now have a conversation with someone else once they understand the definition you are using. Using words without a clear definition, or not being aware of alternate definitions or broader perspectives that are out there, is a problem, and unfortunately not an uncommon one.

2020 garden retrospective – now with more bug pictures!

Gardening and being around my small urban garden definitely brought me some comfort during the long Covid-impacted spring, summer, and fall. A silver lining of being forced to work from home was being able to work outside some. Anyway, below I’ll just tell my story in pictures.

Black Swallowtails are not rare but they are just fun to watch, and their big fat green caterpillars are fun for the young and young at heart. In addition to bicycle tires, they like the fennel and celery in the garden, neither of which I had to plant this year. The fennel is a hardy perennial with a deep taproot that also spreads aggressively by seed. In fact, I had to start pulling fennel aggressively this year except for a couple spots where I decided it was allowed. The celery (which I mistook for flat-leafed parsley at the farmer’s market years ago) seems to be self-seeding and coming back each spring. There was no parsley in evidence in the garden this year.

Black Swallowtail

We saw quite a few monarchs around. This one is on butterfly milkweed, which really started to take over parts of the garden this year. The monarch didn’t cooperate and spread its wings for a nice photo. This should be a host plant, but sadly we did not see any Monarch caterpillars in evidence. I feel good doing my small part in a small urban garden for this endangered species. We made a brief trip to Cape May, New Jersey in October during the fall bird and butterfly migration, and this is just an amazing thing to see – Monarchs just flitting by every few minutes, adding up to millions I would imagine over time!

Some other plants you can see here are purple hyssop (slightly past its prime) and the fennel just starting to bloom. In the background is the neighbor’s ornamental grass, which is interesting but getting completely out of hand. If I didn’t constantly hack at it my garden would be gone in a few years.

Monarch on Butterfly Milkweed

Here’s another (slightly more photogenic) Monarch on a sunchoke flower. The sunchoke, which I planted last year, started to get aggressive this year. I don’t really mind because they are shallow-rooted and easy to pull where I don’t want them. I did notice some squirrels digging them up in the fall and “squirreling them away” in neighbors’ gardens, lol. The sunchokes and hyssop in particular attracted lots of bumblebees which were fun to watch but did not cooperate for photos. Mountain mint was another plant that seemed to attract lots of bumblebees.

Monarch on Sunchoke

We had a bumper crop of milkweed bugs this year. They’re harmless and I think they are super cool, but I can appreciate they might be creepy to people who just don’t like bugs. This is what the butterfly milkweed looks like after it is done flowering and starts to grow seedpods. There was also a lot of common milkweed in the garden which I didn’t plant but leave alone whenever I see it. I notice that friendly neighbors and their gardeners tend to pull theirs, which I will not judge (in case any of you are reading this) but all the more reason for me to do my small part to support native plants and ecosystems.

Milkweed Bugs

Completing the butterfly milkweed life cycle, here the seed pods are bursting open and preparing to scatter their goodness to next year’s garden. The milkweed bugs are still around, but I noticed after about this point they just started to crawl away and scatter. I don’t know exactly where they go. The white flowers you can see here are garlic chives, which are super cool and attract lots of bees and harmless little wasps. They (the garlic chives, not the pollinators) are getting just a bit aggressive though.

Butterfly Milkweed Seed Pods

This giant pumpkin vine just volunteered, probably as a result of throwing last year’s Halloween pumpkin in the compost. Either that or the squirrel’s who shredded other peoples’ Halloween pumpkins (we have learned not to put ours out too early) might have buried the seeds. It didn’t grow any pumpkins though, maybe missing some key nutrient?

Volunteer Pumpkin

The spotted lanternflies invaded Southeast Pennsylvania with a vengeance this year. This is an invasive species from Asia that is almost certainly here for good now. They didn’t do any obvious damage to my trees (including this Asian persimmon) but we will see what the future holds. They don’t bite, unlike the mosquitoes we had in abundance. We mostly worried about one particular species of virus this year, but others like west Nile, Lyme disease, and Zika are still around, and with climate change I will not be surprised if tropical diseases like Dengue are on the way. Can we apply the new vaccine development technologies to work on some of these, please?

Spotted Lanternfly on my Persimmon Tree

We had lots of stuff in pots. From left to right here, Thai “holy” basil, Asian long beans, Thai “sweet” basil, sunflowers (“Autumn beauty”, which lived up to their name and I recommend, Thai jasmine. Lots of bell peppers also volunteered this year, but no hot peppers – in past years lots Thai red peppers have been in evidence.

Pots

Maypop was my “try again” species this year. With the last few winters being so mild, I am hoping to see it again this spring. The new species I decided to add this year was a low, evergreen groundcover called bearberry. I didn’t take good pictures of it, and anyway it is not photogenic at this point, but I have high hopes for its future.

Maypop

And finally, the dwarf Asian persimmon turned a nice shade of orange to wrap up the year. It is 3 or 4 years old, and flowered but did not set any fruit this year. My other tree is a dwarf Asian pear. It had some kind of leaf spot and looked a bit sickly much of the year, but it did set a fair amount of fruit, of which the score was humans 2, squirrels the rest. They were good, and that is an all time high score for the humans!

Dwarf Asian Persimmon Fall Foliage

bumble bee watch

If you have some free time or are looking for an outdoor project with kids, you can take pictures of bumble bees and upload them to this website. Scientists there can help you identify them and tell you if they are rare.

Bumble bees seem to like my anise hyssop, milkweed, and sunflowers especially. I tried to take a photo of one just now but it turns out they don’t always sit still for photos. There is only so much you can do for wildlife in an urban situation, but one thing you can do is plant to help bees and butterflies, then have friendly conversations with family, friends and neighbors when they ask what the heck you are doing in your “overgrown” garden and when your “weeds” make attempts to expand beyond your borders.

June 2020 in Review

In current events, the coronavirus crisis in the U.S. is spinning out of control as I write this in early July. I made a list of trackers and simulation tools that I have looked at. Asian countries, even developing countries, pretty much have it under control, Europe is getting it under control, and the U.S. and a few other countries are melting down. Some voices are very pessimistic on the U.S. economy’s chances to come back. So of course I’m thinking about that, but I don’t have all that many novel or brilliant ideas on it so I’m choosing to write about other things below. Most frightening and/or depressing story:
  • The UN just seems to be declining into irrelevancy. I have a few ideas: (1) Add Japan, Germany, India, Brazil, and Indonesia to the Security Council, (2) transform part of the UN into something like a corporate risk management board, but focused on the issues that cause the most suffering and existential risk globally, and (3) have the General Assembly focus on writing model legislation that can be debated and adopted by national legislatures around the world.
Most hopeful story:
  • Like many people, I was terrified that the massive street demonstrations that broke out in June would repeat the tragedy of the 1918 Philadelphia war bond parade, which accelerated the spread of the flu pandemic that year. Not only does it appear that was not the case, it is now a source of great hope that Covid-19 just does not spread that easily outdoors. I hope the protests lead to some meaningful progress for our country. Meaningful progress to me would mean an end to the “war on drugs”, which I believe is the immediate root cause of much of the violence at issue in these protests, and working on the “long-term project of providing cradle-to-grave (at least cradle-to-retirement) childcare, education, and job training to people so they have the ability to earn a living, and providing generous unemployment and disability benefits to all citizens if they can’t earn a living through no fault of their own.”
Most interesting story, that was not particularly frightening or hopeful, or perhaps was a mixture of both:
  • Here’s a recipe for planting soil using reclaimed urban construction waste: 20% “excavated deep horizons” (in layman’s terms, I think this is just dirt from construction sites), 70% crushed concrete, and 10% compost

Technosols

A technosol is an artificially created planting/structural medium from manmade materials, such as construction debris and compost. This article from Ecological Engineering journal says a mix of 20% “excavated deep horizons” (in layman’s terms, I think this is just dirt from construction sites), 70% crushed concrete, and 10% compost might work. If we truly want green cities, and we don’t want to reduce natural habitats to wastelands by harvesting materials from them to green our cities, this could be a good approach.

May 2020 in Review

You can’t say that 2020 has not been interesting so far. The Covid-19 saga continued throughout May. I certainly continued to think about it, including a fun quote from The Stand, but my mind began turning to other topics.

 

Most frightening and/or depressing story:

  • Potential for long-term drought in some important food-producing regions around the globe should be ringing alarm bells. It’s a good thing that our political leaders’ crisis management skills have been tested by shorter-term, more obvious crises and they have passed with flying colors…doh!

Most hopeful story:

Most interesting story, that was not particularly frightening or hopeful, or perhaps was a mixture of both:

  • There are unidentified flying objects out there. They may or may not be aliens, that has not been identified. But they are objects, they are flying, and they are unidentified.

native plant and pollinator gardening in Pennsylvania

This post has a ton of information on gardening with native plants and gardening for pollinators in Pennsylvania – sources of plants and seeds, recommended species and combinations of species for various conditions, and links to a variety of government and non-profit organizations that can provide even more information.