Tag Archives: urban ecology

November 2017 in Review

Most frightening stories:

  • I thought about war and peace in November. Well, mostly war. War is frightening. The United States of America appears to be flailing about militarily all over the world guided by no foreign policy. Big wars of the past have sometimes been started by overconfident leaders thinking they could get a quick military victory, only to find themselves bogged down in something much larger and more intractable than they imagined. But enemies are good to have – the Nazis understood that a scared population will believe what you tell them.
  • We should probably be sounding the alarm just as urgently, if not more urgently, on biodiversity as we are on global warming. But while the case against global warming is so simple most children can grasp it, the case against biodiversity loss is more difficult to articulate.
  • A theory of mass extinctions of the past is that they have been caused by massive volcanic eruptions burning off underground fossil fuels on a massive scale. Only, not quite at the rate we are doing it now. Rapid collapse of ice cliffs is another thing that might get us.

Most hopeful stories:

Most interesting stories, that were not particularly frightening or hopeful, or perhaps were a mixture of both:

  • You can get an actuarial estimate of your life span online. You can also search your local library catalog automatically whenever you consider buying a book online. Libraries in small, medium, and large towns all over the U.S. appear to be included. Only, not my library. Boo, Philadelphia Free Library.
  • “Transportation as a service” may cause the collapse of the oil industry. Along similar but more mainstream lines, NACTO has released a “Blueprint for Autonomous Urbanism“, which is my most popular post at the moment I am writing this.
  • It’s possible that the kind of ideal planned economy envisioned by early Soviet economists (which never came to pass) could be realized with the computing power and algorithms just beginning to be available now.

 

game of (bee) thrones

Queen bees demand, and receive, absolute loyalty from their hives. When they are nearing the end of their reigns, they try to arrange to keep their family in power and have one of their daughters assume the throne. But that doesn’t always work out and the struggle over succession can be pretty brutal. This might give George R.R. Martin some ideas.

As far as I can tell, my queen died sometime in the spring. Queens typically live for about four or five years, so this caught me by surprise. A new queen, however, is a regular event in the life of a hive. Beekeepers frequently replace their queens every year or two to introduce genetic variety and ensure that the hive has a strong monarch who can lay enough eggs to keep the population up. Bees can also raise their own queen, and when I did an inspection early that spring, I was pleased to see that mine had taken the initiative. Before she died, my old queen must have laid a few fertilized eggs that worker bees raised as replacements. They would have selected six or seven fertilized (female) eggs and fed them only royal jelly. When the first queen hatched, she would have immediately killed any unhatched competition and ideally flown a few mating flights, storing enough semen in her abdomen to spend the rest of her life laying eggs.

While a newborn queen may seem ruthless, the success of a beehive hinges on allegiance to its queen. Though she can mate with an average of 12 different drones, there is only one queen, which makes for a hive of closely related bees. As a new queen begins to produce her own pheromones, the hive slowly aligns with her as the old bees die and new workers hatch. In a sense, the hive is genetically wired to be loyal to the monarchy. If the hive was to raise multiple queens, or if the workers were to start laying eggs, the interests of the population would slowly fracture…

Bees have about 165 pheromone receptors on their antennae and though it’s not entirely clear how workers “decide” what to do and when (the question of agency is still very much up for debate), it is certain that the queen’s pheromones prompt them to go about their business. When the reigning monarch dies or stops laying eggs in her old age, the change in her pheromones prompts the hive to raise a replacement, as my hive had done. Similarly, if a new queen arrives and releases her pheromones before those of the old queen have dispersed, the hive will consider the new queen an invader, and kill her. Above all, they are loyal to their queen. I did not fully grasp this fact. Because I waited only six hours between queens, the worker bees probably stung my new queen to death within an hour.

Swale

Swale is a public food forest on a barge in New York City. Here’s what they’re growing:

Swale’s plant community is made up of perennial native fruit trees and shrubs, leafy self-seeding annuals and salt loving grasses. Our model for landscape design is inspired by edible forestry,  permaculture, and salt-tolerant estuary ecosystems. Our plants have come from many generous donations from Greenbelt Native Plant Center, the New York City Parks Department and Visitors onboard! Our plant list is always expanding. Want to bring a plant onboard Swale? Let us know!

Here’s what’s currently onboard:

Canopy
Beach Plum, Black Chokeberry, Black Tupelo, Black willow, ‘Enterprise’ Apple, ‘Goldrush’ Apple, Fuyu Persimmon, Goji Berry, Hawthorn, Italian Alder, Newtown Pippin Apple (native to Queens NY!), Liberty Apple, ‘Northern Spy’ Apple, Northline Serviceberry, Pitch pine, Red Chokeberry, Sweetbay Magnolia

Shrub
American Red Raspberry, Arkansas Blackberry, Blue Ridge Blueberry, Dogbane, Eastern Juniper, False Indigo, Flame Willow, Golden Curls Willow, Gooseberry, Missouri River Willow, Northern Highbush Blueberry, Pennsylvania Blackberry, Red Stem Dogwood, Rosemary, Sassafras, Triple Crown Blackberry, Winterberry

Herbaceous
Asparagus, American, Blackgrass, Black eyed Susan, Buck’s Horn Plantain, Bugleweed, Anise Hyssop, Aster (New England), Bee Balm, Black Eyed Susan, Borage, Comfrey, Dandelion, Daylily, Echinacea, Evening primrose, French Sorrel, Garlic Chives, Goldenrod, Ground Cherry, Hopi Red Dye Amaranth, Lavender, Lemon Balm, Lettuce, Lovage, Meadowsweet, Milkweed, Miners Lettuce, Oregano, Peppermint, Perpetual Swiss Chard, Red Mustard, Red Russian Kale, Roman Chamomile, Rosemallow, Scallion, Saltgrass, Saltmeadow rush, Sea pea, Shore little bluestem, Spotted Joe Pye Weed, Stinging Nettle, Swamp Goldenrod, Sylvetta Arugula, Tansy, Virginia mountain mint, White Avens, Wild leek, Whorled mountain mint, Yarrow

Ground Cover
Creeping Thyme, Creeping raspberry, Golden oregano, Purslane, Strawberries, White Clover, Wild Low bush blueberry

Rhizosphere
Adam’s yucca, Groundnut, Jerusalem Artichoke, Walking Onion, Wild Yam

Vertical Layer
Clematis, Grapes, Hardy Kiwi, Hops, Scarlet runner beans

wildlife resilience and urban parks

This article suggests that urban parks are not as good as rural reserves for supporting biodiversity, but they can still play a role in improving the resilience of species. Of particular interest to me are some the measures ecologists are coming up with to try to define and measure resilience.

Urban parks can maintain minimal resilience for Neotropical bird communities

Birds may use urban parks as shelter and refuge, contributing with numerous ecosystem services upon which humans and other organisms depend on. To safeguard these services, it is important that bird communities of urban environments hold some degree of resilience, which refers to the capacity of a system to absorb disturbances and changes, while maintaining its functions and structures. Here we assessed the resilience of the bird community inhabiting an urban park in the Southeast region of Brazil. We classified birds in feeding guilds and identified discontinuities and aggregations of body masses (i.e., scales) using hierarchical cluster analysis. We then calculated five resilience indices for our urban park and for a preserved continuous forest (reference area): the average richness of functions, diversity of functions, evenness of functions, and redundancy of functions within- and cross-scale. The urban park had less species, lower feeding guild richness, and lower within-scale redundancy than the reference area. However, they had similar proportion of species in each function, diversity of functions, evenness of functions, and cross-scale redundancy. The lower species richness and, consequently, the lack of some species performing some ecological functions may be responsible for the overall lower resilience in the urban park. Our results suggest that the bird community of the urban park is in part resilient, as it maintained many biological functions, indicating some environmental quality despite the high anthropogenic impacts of this area. We believe that urban forest remnants with more complex and diverse vegetation are possibly more likely to maintain higher resilience in the landscape than open field parks or parks with suppressed or altered vegetation. We propose that raising resilience in the urban park would possibly involve increasing vegetation complexity and heterogeneity, which could increase biodiversity in a large scale.

June 2017 in Review

Most frightening stories:

  • The Onion shared this uncharacteristically unfunny observation: “MYTH: There is nothing mankind can do to prevent climate change. FACT: There is nothing mankind will do to prevent climate change”. It’s not funny because it’s probably true.
  • Water-related hazards including flood, drought, and disease have significant effects on economic growth.
  • There were 910 deaths from drug overdose in Philadelphia last year. Interestingly, I started writing a post thinking I might compare that to car accidents, and ended up concluding that the lack of a functioning health care system might be our #1 problem in the U.S.

Most hopeful stories:

Most interesting stories, that were not particularly frightening or hopeful, or perhaps were a mixture of both:

  • Tile is a sort of wireless keychain that can help you find your keys, wallet, and those other pesky things you are always misplacing (or your significant other is moving, but won’t admit it).
  • Fleur de lawn” is a mix of perennial rye, hard fescue, micro clover, yarrow, Achillea millefolium, sweet alyssum, Lobularia maritima, baby blue eyes, Nemophila menziesi, English daisy, Bellis perennis, and O’Connor’s strawberry clover, Trifolium fragiferum.
  • Traditional car companies are actually leading the pack in self-driving car development, by some measures.

pets and ecological footprint

This article from Alternet asks which pets are the most environmentally friendly. Their conclusion: chickens, ducks, goats, and rabbits. This makes sense, although keeping these in an urban environment could be impractical unless we are going to do it on a communal basis (actually not a bad idea). Dogs and cats are a mixed bag. I have mixed feelings – I think in our highly industrialized, urbanized modern lives that are so unnatural to begin with, pets give us some sense of connection to nature and the natural environment that would otherwise be missing. That they prime our immune systems to some mildly threatening pathogens and allergens could actually be a good thing, particularly for children. I don’t like the idea of cats killing birds, although if the area weren’t industrialized and urbanized there would probably be all kinds of predators going after the birds. There would also be a lot more birds, of course.

I have always wondered about the ecological impact and ethics of keeping semi-domesticated animals that occur naturally in the local environment, or would if it hadn’t been industrialized and urbanized. Collecting them in the wild is clearly wrong in my view, but if they are bred domestically and kept in humane conditions, it doesn’t seem bad at all. I’m thinking small native snakes, turtles, and fish in particular. Even insects and spiders if you are into that sort of thing. Beekeeping is a cool hobby if you have the interest and time. Granted, none of these are furry or cuddly. If you have some outdoor space, I wonder if keeping a semi-domesticated raccoon or de-scented skunk is really that bad. These animals would be around anyway. I don’t like the idea of confining birds at all. They are so easy to attract and enjoy in their wild condition. Butterflies and other pollinators are also easy to attract and fun to watch. For that matter, plants are kind of fun to watch, if you ask me. Watching plants grow forces you to slow your body and mind down to their speed for a few minutes each day, and if you do that for a few minutes each day, the way they grow and change and interact with each other and the environment is really fascinating over the course of the growing season.

clean water is not enough

This article presents evidence for the expected trend in biodiversity of riparian areas (whether lake, river, stream, etc. I can’t tell from the abstract) in response to urbanization. Large water features might be the one piece of the landscape that urban development has trouble erasing. But by changing the nature of the shoreline and adjacent habitat, you would expect a degradation in ecosystem quality, even if the water quality itself is perfectly fine (which it often is not, of course). The question is, could you design a shoreline and adjacent city that would support a significant fraction of the biodiversity and ecosystem function that was once there? In other words, a smaller nature that is still healthy? Or should we write off the idea of a high-functioning urban ecosystem and focus on protecting more wild areas? Well, I don’t know but I can guarantee that not making a serious attempt at either one will not lead to a good outcome.

Decadal declines in bird abundance and diversity in urban riparian zones, Landscape and Urban Planning, Volume 159, March 2017, Pages 48–61

Urbanization is frequently cited as a major driver of species losses worldwide; however, most studies in urban areas use a space-for-time substitution approach to document effects of urbanization through time. Ultimately, understanding the effects of urbanization on biodiversity requires long-term datasets. We examined long-term changes in bird assemblages at 12 riparian sites in the greater Phoenix metropolitan area and nearby Sonoran Desert region, featuring a range of human modifications and levels of water flow. Riparian areas in arid cities represent a key habitat type that is sensitive to human modification and supports high levels of species diversity. We used long-term data to: (1) explore variation in bird communities as a function of water permanence and degree of human-modification; (2) identify which environmental variables best describe differences found across riparian site types; and (3) assess how riparian bird communities, abundance, and species richness have changed through time. Engineered riparian sites supported more broadly distributed generalists; whereas, natural riparian sites supported more specialists. Sites with perennial flows had more vegetation and water compared to ephemeral sites and engineered sites had more impervious surface compared to natural sites. In nearly all comparisons, bird species richness, diversity, and abundance declined across riparian types during the period of study, even for common species. Bird communities in natural settings have changed more than communities at engineered sites. Overall, the riparian bird community is shifting toward urban dwelling, resident species that are characteristic of riparian sites with less water and more impervious surface.