Wednesday, August 19, 2015

Tuesday at the 100th Meeting of the Ecological Society of America

I moved between a few different sessions on Tuesday, August 11, 2015 at #ESA 100.  There were so many great urban ecology research talks to choose from, many of which have direct applications to how we build and manage gardens and other urban or suburban greenspaces.  A few highlights are below.

OOS13 - New Perspectives for Ecology during the Anthropocene: new paradigms, technologies and collaborations

#3:  Friedman et al. 'Modeling qualitative social data: collaborative approaches for and continuing challenges to crossing the qualitative-quantitative divide':  I sat in on this talk, because I am in the midst of my own qualitative-quantitative data divide.  Qualitative data includes the stories or narratives that people tell to researchers.  Quantitative data includes numbers and statistics.  I'm much more comfortable working with quantitative data, but I'm working on a project where the principle investigator works primarily with qualitative data.  Coming to a common understanding how to approach research questions, gather data and build analytical models has been a chore!  I was hoping that this talk would give me some tips for how to cross a disciplinary divide, so that we can maximize the impact of our project.  Friedman is an anthropologist and a researcher at the Center for Applied Social Research at the University of Oklahoma.  He presented a case study from one of his interdisciplinary projects, where the narratives (qualitative data) were used to identify the variables that should be quantified to build an explanatory model.  For complex problems or issues, where the outcome is the result of many factors (e.g. childhood obesity, water levels in reservoirs, urban pollution) ~ this can help to efficiently and specifically target research efforts to factors that are most meaningful to the people who are living and experiencing the problems that are being studied.

#8:  Ellis 'Ecology in an anthropogenic biosphere: new tools for anthropocene ecologists':  this talk presented an overview of Ellis' recent paper in Ecological Monographs.  Ellis argues that humans have transformed ecological relationships, and that sociocultural niche construction has played an important role in the development of human societies, but has also been responsible for the transformation of the biosphere.  Ultimately, Ellis argues that to study ecology, we need to understand and study human socio-cultural processes.  As an urban ecologist, I loved this presentation.  Ecology divorced from human culture, social interactions and behavior is missing a huge piece of the picture.  I'm thrilled to see more and more ecologists arguing for a truly integrated socio-ecological approach to the study of nature.  A few things that stuck with me from Ellis' talk:

  • Darwin was the first to note that culture evolves faster than genomes.  Ellis cited BronyCon (which was sharing convention space with ESA) as an example of this phenomenon.  
  • The term for anthropogenic biomes is anthromes.  This was a new term for me.

OOS19 - Green Roof Biodiversity and the Food Web

#5:  Snodgrass 'Plant selection on ecological green roofs'.  Snodgrass runs a commercial nursery that specializes in green roof plants ~ the only nursery in the United States to do so!  He's also written two Timber Press Books on green roofs, and consults on green roof projects around the United States.  Things that stuck with me from Snodgrass' talk:

  • from a design point of view, it's important to decide if you want your green roof to function as a garden (e.g. looks beautiful), or to function as a machine (e.g. filters water or insulates a building).  That decision will guide your design choices.
  • successful green roof plants often come from pioneer communities whose succession is arrested or halted, because of poor growing conditions that inhibit other species.  Successful green roof plants tend to be specialists, and not generalists.
  • green roof media reaches its wilting point 48 hours after a rain event.  So, green roof plants must be able to tolerate going from flood to drought conditions in a short period of time.
  • can you grow vegetables on a green roof?  You can, but is it a good idea?  Vegetables need nutrients, and what will you do with the nutrients coming off of the roof?  You should also measure deposition of atmospheric pollutants that land on the roof, to determine if it is a safe site to grow food.

OOS32 - Contributions of Urban Agriculture to the Urban Ecosystem

#1 Harada: 'Biogeochemistry of the Brooklyn grange, and urban rooftop farm'.  The Brooklyn Grange is a 0.6 ha farm on top of an 11-story building that used to be part of the Brooklyn Navy Yard.  I felt lucky to hear this talk, immediately after Snodgrass' talk in another session.  Since Snodgrass asked 'what do you do with all of the nutrients coming off of the roof?', I wanted to hear what Harada and colleagues found.  Indeed. they documented that an urban rooftop farm is a 'leaky' system.  You apply a lot of water, and a lot of water comes off of the roof.  You apply a lot of fertilizer (in the form or compost and other organic nutrients), and a lot of nitrogen comes off of the roof.  The Brooklyn Grange has a ton of potential as a demonstration of successful urban farming, but it will be interesting to hear how the farm managers respond to the data that shows that a lot of nitrogen is coming off of the roof, and flowing directly into local waterways.  If urban, rooftop farming is going to be a sustainable practice ~ we need to do a better job managing water loss and nutrient leaching.

#6, MacIvor and Packer 'Bee hotels to enhance native pollinators: a premature verdict?'.  This talk examined the efficacy of bee hotels for attracting native pollinators.  The full methods and data are accessible in this PLOS paper.  Highlights:

  • you'll find more wasps than bees in a 'bee' hotel
  • perhaps we should stop calling them 'bee' hotels and instead call them biodiversity hotels, because these structures provide habitat for more than just bees
  • only ~ 30% of all bees nest in cavities, such as those provided by bee hotels.  If we're really serious about conserving bees, we need to look to the ground . . . since the vast majority of native bees are ground nesters.  This last point has tie-ins to my own research, which I presented on the last day of the meeting.

Sunday, August 16, 2015

Monday at the 100th Meeting of the Ecological Society of America

I last attended a meeting of the Ecological Society of America (ESA) meeting in 2005.  That year, a few of my graduate students and I travelled to Montreal, Canada to present our research on insect diversity in New York City gardens.  I enjoyed reconnecting with friends and colleagues, but I left feeling like the ESA didn't have a place for us or our developing research program in urban ecology.

Fast forward 10 years:  I was thrilled to see that this year's meeting ~ the 100th meeting of the ESA ~ was full of opportunities to learn from and network with ecologists, engineers, geographers, designers, sociologists, educators and spiritual leaders who are keenly invested and involved in understanding how to build more sustainable, just and healthy cities.

What did I learn from #ESA100?  What inspired me?  Over the next few days, I'll put together my day-by-day impressions.  First up . . .

Monday, August 10, 2015

I started my morning by slipping into the Plenary session. Esteemed ecologists David Tilman and Margaret Palmer were joined by former US Representative and current Chief Executive of AAAS Rush Holt to set the stage for a conversation on 'what will a successful environmental agenda look like for the next 5, 10, 100 years?'.

Notables from the plenary session:

  • David Tilman on ethanol:  'I thought we'd be hard pressed to make a fuel worse than gasoline, but we've done it'.
  • David Tilman on the importance of agriculture to sustainability: suggested that to feed the world while conserving biodiversity, we need modern, precision agriculture and a healthier diet.
  • David Tilman on the impact of diet on the environment:  asked a rhetorical question 'how can we convince 11 billion people to change their diet?', and suggested that a Nobel Prize should go the chef who can create healthy, delicious and sustainable dishes.
  • Rush Holt on the status of science, today:  'Americans have lost their reverence for evidence.'
  • All speakers noted the importance of making science accessible to all.  I could not help but notice the irony of sitting in a hotel conference room with a mostly white audience . . . not too far from where the Baltimore riots occurred.  I grew up not too far from where we sat.  As a child, I didn't know anyone who was a scientist.  I never would have believed that *I* could be a scientist, if it weren't for a teacher who took the time to cultivate the confidence I needed to believe that a career in science was possible, for a kid like me.  Taking the time to reach out to others, inviting them to participate, and providing them with opportunities, mentoring and support is so incredibly important if we are sincere about diversifying science and the field of ecology.  Judging from the demographics of those at #ESA100, we still have a ways to go.
  • POTUS wished the ESA a happy birthday, and thanked ecologists for our contributions to society.  

In the afternoon, I moved between several different sessions.  Some interesting tidbits:

  • Lindell et al. 'Birds in orchards: economic, biological, and social aspects of ecosystem services':  birds such as starlings cause a lot of damage to fruit orchards.  The researchers installed nesting boxes to attract kestrels that might help control the fruit-eating birds.  Analysis of kestrel diet showed that they mostly eat insects and mammals, but that they occasionally eat starlings.  They then surveyed consumers to see what type of control they would prefer for pest birds.  Consumers preferred, and would be willing to pay more, for fruit that was protected from pest birds by kestrels . . . compared to the use of pellet guns or other deterrents for bird control.
  • Lopez et al. 'Drivers of plant species composition in an urban landscape: which variables matter most?':  looked at plant species composition in forest fragments along an urban gradient. Among other factors, researchers found that distance to urban centers was positively related to the prevalence of invasive species in forest fragments.  This suggests that horticultural use of non-native species played an important role in the introduction of invasive species into forest fragments.
  • Thorn et al. 'Quantitative scenarios for land cover change in New Hampshire: what is the potential impact on ecosystem services?':  for this series of simulations, ecosystem service degradation seemed to take hold when the percent of paved surfaces in the landscape surpassed 10%.
  • Cattell Noll et all. 'How does consuming organic products affect my nitrogen footprint?': the University of Virginia has developed an online tool that you can use to calculate your nitrogen footprint.  How cool!

Monday, June 29, 2015

Milkweed for Monarchs: does it make sense in Oregon?

(Originally published in the March 2015 issue of The Gardener's Pen newsletter)

Larvae (left) and adult (right) of the Monarch butterfly, Danaus plexipuss.  Photo Credit:  Dr. Jeffrey Miller, Oregon State University Professor of Entomology.

Ecology of the Monarch Butterfly, Danaus plexippus,  in the Pacific Northwest:  Monarchs are common on the east side of the Cascade Mountains, but very uncommon on the west side.  Monarch caterpillars feed on milkweed during the early summer.  Adults fly from spring to fall when they migrate south.  Found in open habitats, particularly along roadsides and fencerows. (Adapted from: Miller and Hammond, 2003. Lepidoptera of the Pacific Northwest. USDA FHTET-03-11)

Monarch butterflies are specialist insects, with specialized digestive systems and feeding behaviors that are adapted for feeding on plants in the genus Asclepias (milkweed plants).

Asclepias plants have toxic chemicals (cardiac glycosides) and a latex sap that deters most insect feeding.  Monarchs store the cardiac glycosides in their exoskeleton, which circumvents the need to metabolize these nasty chemicals and also makes them poisonous to vertebrate predators.

The latex sap of milkweeds gums up the mouthparts of many insects ~ causing them to starve.  Monarchs deal with the latex sap by clipping the veins on milkweed leaves, allowing the latex to ‘bleed out’ of the plant before they feed.

Monarch adults are migratory.  East of the Rocky Mountains, monarch butterflies fly south to overwintering sites in Mexico each the fall, and return north in the spring.  Scientists have have noted that overwintering populations of Monarchs in Mexico have significantly declined over the last two decades (Brower et al. 2012).  Three factors have been implicated in the decline of eastern monarchs:  (1) loss of forest habitat in Mexico, where the butterfly overwinters; (2) loss of breeding habitat/milkweed plants in the United States due to land development and increased use of herbicides in Roundup-Ready crop fields; (3) occasional extreme weather conditions that decrease the length of the breeding season.

Known migration routes, breeding territories and overwintering areas for Monarch butterflies.  Map reproduced courtesy of

Although most North American monarchs overwinter in Mexico, those that live west of the Rocky Mountains generally overwinter at one more than 300 sites along the California coast.  These monarch ‘groves’ tend to be within a few km of the ocean, which is thought to moderate temperature, and are usually protected from the elements in some fashion.  Unlike eastern monarchs, who may fly thousands of miles from Canada to Mexico, western monarchs usually migrate no more than 100 miles.  Their breeding sites are thought to range as far north as western Canada, and as far south as southern Arizona, in the mountains and foothills of California, the Pacific Northwest and the Great Basin States.  General dogma has been that monarchs may wander into southern Oregon, during their spring migration to breeding sites or their fall migration to overwintering sites in California.  But the truth is, we really don’t know that much about where western monarchs breed.

Still, many groups have advocated that Oregon gardeners plant native milkweed plants to support western monarchs ~ particularly because there has been about an 80% decline in western monarch numbers recorded from California overwintering sites since 1997.  The factors implicated in western monarch decline include:  (1) milkweed loss following prolonged drought, (2) land development that reduces overwintering habitat and/or breeding habitat, and (3) pesticide use.

Does it make sense for Oregon gardeners ~ particularly those in Western Oregon ~ to plant milkweed to support western monarchs, given that conventional dogma suggests that monarchs don’t migrate through or utilize breeding sites in Western Oregon?

I suggest that it can’t hurt for Oregon gardeners to plant milkweed in an effort to support the Western Monarch.  Although monarchs may not be common outside of southern Oregon, what little data there is suggests that monarchs may at least be migrating through ~ and in some cases may be breeding in ~ broad areas of Oregon.  What data do I have to support this assertion?

  1. A map of the known and potential monarch breeding areas in the western U.S. includes (as best as I can read) monarch breeding records in Jackson, Josephine, Klamath, Lake, Harney, Lane, Benton, Washington, Multnomah, Wasco and Deschutes counties.  I do not have access to the data that was used to construct the map, but it appears as if the researchers are relying on museum records.  So, the identified breeding sites probably represent a record of a monarch specimen from a museum, which was collecting during the summer at a particular locale.  If this is true, there are records of summer monarchs in both eastern and western Oregon locales.  These may be ‘vagrants’ that wander off of their migration path, but they may also be breeding adults.
  2. The Butterflies and Moths of North America site has user-verified records (with photos) of monarchs reported for nearly every Oregon county.  I was able to access details for the three most recent sitings.  I’ve paraphrased the details of the sitings, below, so that you can see that there is evidence of monarch breeding in southern Oregon (caterpillars in Josephine County) and adult migration through the Willamette Valley (strong adult flights ~ rather than tattered-winged vagrants).
    • June 10, 2014, Benton County, OR, one adult monarch sipping nectar from showy milkweed (Asclepias speciosa).
    • June 21, 2014, Black Bear Bar along a wild and scenic section of the Rogue River, OR.  Monarch caterpillars munching on showy milkweed.
    • June 20, 2014, Lane County, OR, one adult monarch flying around and sipping nectar from Buddleia.  Flight was strong and direct.  Perhaps a migrant. Over the past few years, several organizations have been promoting the planting of milkweed plants, in order to provide host plants for monarch butterflies.
  3. The adults I've seen in Oregon (Douglas County, Lane County, Linn County) have had intact wings and scales - not what I expect from strays far from their host plants/flight path.

What type of milkweed should you plant?  Opt for native milkweeds, and avoid tropical milkweed (Asclepias curassavica).  The Xerces Society has a wonderful publication that details the milkweed plants native to Oregon.  These include:

  • Asclepias cordifolia (purple milkweed):  scattered in south and southwest Oregon
  • Asclepias cryptoceras ssp. Davisii (Davis’ milkweed): scattered in central and eastern Oregon
  • Asclepias fascicularis (narrow-leaved milkweed):  scattered across Oregon
  • Asclepias speciosa (showy milkweed):  widespread across Oregon

You will most easily be able to find seed of Asclepias speciosa from local nurseries, who may also have Asclepias tuberosa (butterfly weed, native to the Eastern US) and Asclepias syriaca (common milkweed, native to Europe).  Asclepias tuberosa and Asclepias syriaca, like many milkweeds, can have weedy tendencies.  They are called milkWEEDS, after all.  But, with this weediness comes the potential to invade areas outside of your garden.

Thus, when selecting milkweed, try to stick to native species that are appropriate for your area ~ such as Asclepias speciosa ~ in order to limit the introduction of non-native plants in natural areas.