Growing cities and green space

Can urban density increase as well as green area? It depends. Cities without strong urban or green infrastructure regulations can result in sprawling concrete jungles, as green areas are viewed as ‘ready for development’. In cities such as Seattle that have urban growth boundaries, then yes, it can grow more green without the fear of losing what it seeks to protect. But growing urban areas that place a priority on biodiversity, such as Singapore, can do some impressive things. The city population of Singapore grew by 68% between 1987 and 2006. Yet the green footprint in this Garden City grew between 35-47% for the same period. How? Because they planned for it. For more on this head over to https://therevelator.org/urban-ecology-sustainable-cities/

What is the Ecological Landscape Alliance?

“The Ecological Landscape Alliance (ELA) is a nonprofit, member-based organization made up of professionals, businesses and pro-active community members who believe in using landscape practices that are environmentally safe and beneficial.

Our Mission

The Ecological Landscape Alliance (ELA) was founded in 1991. We advocate for environmentally responsible stewardship of land and natural resources in landscaping and horticultural practices of both professionals and the public. Through education, collaboration, and networking, ELA promotes the design, installation, and maintenance of landscapes that are guided by a knowledge of and respect for natural ecosystems.

Our Members

We are diverse in many ways but united in common purpose. We:

Believe in using landscaping practices that are environmentally safe;

Believe that natural systems are the best guide for learning how to develop and maintain healthy landscapes;

Value landscaping methods that are based upon scientific studies and practical experience;

Are committed to educating ourselves and others about ecological landscaping methods; and

Believe that a network of dedicated people can be a powerful agent for change.”

Find out more about ELA at https://www.ecolandscaping.org/about/

Cities are Living Systems Too

photo credit (National Galleries of Victoria https://www.ngv.vic.gov.au/#)

Agrarian Legacy

Lewis et al in Global Change Biology (2006) found that residential soil levels can be impacted from prior land use for up to 40 years later. This might explain why many residences in the southern U.S. have elevated P levels on former agricultural lands. The authors compared former agriculture lands with natural lands and found significant soil differences. They term this a ‘direct agrarian legacy.’ How many other legacies are out there?

Lewis, Kaye, Gries, Kinzig, and Redman. 2006. Agrarian legacy in soil-nutrient pools of urbanizing arid lands. Global Change Biology 12:703-709.

Ecoacoustics of London

Here’s an interesting project that looks at the sound of a major city, including its biodiversity.

“We have created tools to make it easier to monitor the environment in London.

CityNet is a machine-learned system that measures the amount of audible sound made by wildlife and humans recorded using sound recorders. This can be used to give a very detailed picture of how biodiversity and human activities change over time.

We use an interactive map to display the automatically-inferred trends in biodiversity and human sounds at 63 sites of green infrastructure in and around Greater London, UK.”

Find out more here:

http://www.londonsounds.org/about.html

How are species adapting to urban conditions?

Biologists are looking at how species are changing to meet the opportunities or constraints of urban conditions. Rivkin et al (2018) compiled a list of scientific papers published to document selection associated with urbanization:

Nature in the City

"It's wonderful to see what happens when we make nearby nature in the city more accessible to people. This is what we do. We get people, especially urban kids, outside." - Ken Leibach

Urban Ecology: A Natural Way to Transform Kids, Parks, Cities, and the World, 2018, Morgan James Publishing

A roadmap for urban evolutionary ecology

“Urban ecosystems are rapidly expanding throughout the world, but how urban growth affects the evolutionary ecology of species living in urban areas remains largely unknown. Urban ecology has advanced our understanding of how the development of cities and towns changes environmental conditions and alters ecological processes and patterns. However, despite decades of research in urban ecology, the extent to which urbanization influences evolutionary and eco‐evolutionary change has received little attention. The nascent field of urban evolutionary ecology seeks to understand how urbanization affects the evolution of populations, and how those evolutionary changes in turn influence the ecological dynamics of populations, communities, and ecosystems. Following a brief history of this emerging field, this Perspective article provides a research agenda and roadmap for future research aimed at advancing our understanding of the interplay between ecology and evolution of urban‐dwelling organisms. We identify six key questions that, if addressed, would significantly increase our understanding of how urbanization influences evolutionary processes. These questions consider how urbanization affects non‐adaptive evolution, natural selection, and convergent evolution, in addition to the role of urban environmental heterogeneity on species evolution, and the roles of phenotypic plasticity vs adaptation on species’ abundance in cities. Our final question examines the impact of urbanization on evolutionary diversification. For each of these six questions, we suggest avenues for future research that will help advance the field of urban evolutionary ecology. Lastly, we highlight the importance of integrating urban evolutionary ecology into urban planning, conservation practice, pest management, and public engagement.”

From: Evolutionary Applications Pub Date : 2018-11-12 , DOI: 10.1111/eva.12734

L. Ruth Rivkin; James S. Santangelo; Marina Alberti; Myla F. J. Aronson; Charlotte W. de Keyzer; Sarah E. Diamond; Marie‐Josée Fortin; Lauren J. Frazee; Amanda J. Gorton; Andrew P. Hendry; Yang Liu; Jonathan B. Losos; J. Scott MacIvor; Ryan A. Martin; Mark McDonnell; Lindsay S. Miles; Jason Munshi‐South; Robert Ness; Amy E.M. Newman; Mason R. Stothart; Panagiotis Theodorou; Ken A. Thompson; Brian C. Verrelli; Andrew Whitehead; Kristin M. Winchell; Marc T. J. Johnson

Green. Global. Connected.

Big shout out to Sydney, Australia for their visionary urban ecology plans. Sustainable Sydney 2030 is striving to be a leader in urban environmental performance with efforts towards reducing carbon emissions, and creating a network of green infrastructure to reduce energy, water and waste water demands. Check out their urban ecology strategic action plan at https://www.cityofsydney.nsw.gov.au/vision/towards-2030/sustainability/urban-ecology/urban-ecology-action-plan#page-element-dload

What places are the most biodiverse in cities?

A study by authors Salinitro et. al. looked at what environments in an Italian town harbored the most plant species. Published in the journal nature on Oct 11, 2018, the researchers found that landscapes that retained native soil became a refugium for native plants and increased biodiversity. Rooftops and manholes were cited as having the least diversity. Other factors such as paving types had varying biodiversity levels, as well as available moisture levels. This information is distributed via Creative Commons license available at https://creativecommons.org/licenses/by/4.0/

Why are there so many spiders in this house?

A recent study published in Nature (November 2017) looked at where spiders live in houses. Entitled “The Habitats Humans Provide: Factors affecting the diversity and composition of arthropods in houses” authors Leong, Bertone, Savage, Bayless, Dunn & Trautwein found in their study that access to the outdoors and carpeted rooms had more spider populations than house tidiness, pesticide use, and pet ownership. "Our findings suggest that the more opportunities arthropods have to get into a particular room in a home, the more diverse the arthropods in that room are likely to be."

The absurdity of lawns according to MichaeL Pollan

“The conceit of the American suburb is that we’re all in a great park together.”- Michael Pollan
By Radiowest
See it at https://www.theatlantic.com/video/index/569329/michael-pollan/?utm_source=eb

biosphere phone booth IV?

The Next Epoch Seed Library (NESL)

“The Next Epoch Seed Library (NESL) re-imagines the conventional seed bank for a new epoch defined by massive human impact on the global environment. Rather than focusing exclusively on human utility or agricultural heritage, we champion the contributions of weedy plant species most likely to survive and thrive in an unpredictable future.

Stocked with seeds gathered from the vacant lots, street verges, superfund sites and abandoned infrastructure, the seed library provides a gene pool of tough, highly adaptable plants well-suited to live in close quarters with humans and their attendant landscape transformations.

Offering services like soil stabilization, moisture retention, heat island reversal, toxic bio-accumulation and medicinal and nutritional attributes, these plants are the ideal pioneer species, prepared to heal the wounds inflicted by a changing climate unsustainable resource extraction. Spontaneous urban plant communities will form the base of new, novel ecosystems as we move through the bottleneck of the sixth mass extinction. Dedicated to overcoming plant-blindness in contemporary urban life, NESL believes that reciprocal networks of plants and people can provide a solid foundation for building ecologically just communities.”

From http://nextepochseedlibrary.com/#/about/

The verdant ivy clings

”the verdant ivy clings around
Yon moss be-mantled wall
As if it sought to hide the stones
That crumbling soon may fall”
The ivy on the wall, Henry Kendall

Or must it fall? An article published in Nature (June 29, 2018) has found that ivy on limestone walls can actually protect walls from damaging frosts. Coombs, Viles, and Zhang found in their study that ivy provides thermal blanketing for 26-32% additional efficiency. Ivory tower research has found a way to protect itself.

City parks vs. natural areas - is it possible to preserve a natural level of bee richness and abundance in a city park?

“Urbanisation is an expansive process and a majority of insects live in human-modified areas. At the same time, a decrease in pollinator species richness and abundance has recently been observed in Europe, which in turn may have serious ecological and economic consequences. This study investigates the abundance, species richness and functional traits of wild bees in urban city parks in comparison to natural areas. The aim of this research was to assess the potential conservation values of urban green areas for bees. The present study demonstrates that a large and diversified city park may be a favourable habitat for bees, comparable to the natural fauna both in terms of the number and abundance of bee species. However, the study also showed that there were differences in the occurrence of species with different functional traits in the city parks investigated and in the natural landscape.”

Abstract taken from Banaszak-Cibicka, W., Twerd, L., Fliszkiewicz, M. et al. Urban Ecosyst (2018) 21: 599. https://doi.org/10.1007/s11252-018-0756-8

Stormwater Ponds: Ecological benefit or detriment?

You have seen them around your city. That fenced in pond area near the parking lot that you can’t access. What is it? Stormwater ponds capture runoff from buildings and paved surfaces to store and treat water before it enters local streams. The design and management of the ponds can vary widely and often depend upon the amount of water it is built to store. Stormwater ponds can offer some ecological benefit to aquatic plants and wildlife, but as a recent research paper discusses, it depends upon the context of the site. Entitled “A review of the factors that determine whether stormwater ponds are ecological traps and/or high-quality breeding site for amphibians” in Frontiers of Ecology and Evolution (April 2018), authors Laura Clevenot, Catherine Carre, and Pierre Peach, reviewed the literature on stormwater ponds and their impacts on amphibians and found that pond ecology can vary widely. Obviously, pollutants coming in with the stormwater can be a major factor, but adjacent land uses can also impact organisms. The article states that intensive agricultural areas near ponds can deter amphibians. Forests and other wetlands near ponds can however be a positive influence that offer refuge and food. Above is a graphic that show some of the negative influences on wildlife reported in the literature regarding stormwater ponds. This review is allowed under the terms of the Creative Commons Academic License.

Natives or nativars?

A 'nativar' is a term applied to a cultivar of a native species. Cultivars are selected from native species but are chosen for a certain attribute, such as more intense fall leaf color, or flower color, or height. So is a nativar good enough to use in native plantings? Well it depends on the context. If you are planting a landscape restoration project in a wild area its probably a bad idea. If that nativar was grown in a nursery in the midwestern United States to be planted in the heat of Texas, it is definitely a bad idea. A study published in May 2018 in PLOS 1 journal found that native red maple trees had higher water use efficiency as air temperatures increased as compared to cultivars. The study found there are physiological differences due to genetic backgrounds and local environments. The study is titled "Variation in photosynthesis and stomatal conductance among red maple (Acer rubrum) urban planted cultivars and wildtype trees in the southeastern United States" by Eleanor C. Lahr, Robert R. Dunn, and Steven D. Frank

Some spiders don't like it hot

According to a 2017 study, increasing urban temperatures alter spider populations. Published in the Journal of Urban Ecology January issue, researchers Emily Meineke and Anna Holmquist, et al, found that ghost spiders 'disappeared' due to increasing heat, and not because of other predators or lack of food. As spider populations decrease tree-munching herbivorous insects can increase, putting more pressure on vegetation.

Trees make people with depression feel more secure

"It's a planting that has quite organic and quite natural form. And the idea behind that is rather than geometry and straight lines - you don't want people to feel forced through the garden, they need to feel compelled to move into it and meander round it at their own pace, and feel at complete ease when they move through the garden.” --Matt Keightley, garden designer of RHS Feel Good Garden

available at https://www.telegraph.co.uk/news/2018/05/22/wild-untidy-gardens-better-mental-health-designer-claims-chelsea/

below ground level

bark eventually    dissolves

            into its base chemicals     purging fluid

discolored wildflowers

            amongst generic tombstones

of energies trapped

    then released again into the wider

univers e

--poem by Astra Papachristodoulou, full poem entitled “below ground level” at

https://ypn.poetrysociety.org.uk/workshop/the-august-challenges-1-edgelands/

How are species adapting to human contexts?

“The potential magnitude of unintentional human selection should not be underestimated.”

Authors Kathryn G. Turner, Christopher J. Schell, and Brook T. Moyers report in their recent article “Genomics of Adaptation to Human Contexts” (Journal of Heredity, 2018, Vol. 109, No. 2) the summaries of a one day symposium of geneticists and their published papers. One key paragraph of their article states:

“Moyers et al. (this issue) review the evidence for a genetic “cost of domestication,” and that with few exceptions, domesticated lineages show signs of increased deleterious genetic variation compared to their wild relatives. These signs include increased genome-wide linkage disequilibrium, reduced genetic diversity, increased numbers or substitutions of nonsynonymous relative to synonymous mutations, and more numerous or frequent mutations that annotate as deleterious in comparative analyses. The same pattern is found when comparing modern domesticated lineages subject to recent intense artificial selection (elite or improved varieties) against older domesticated lineages (landrace or noncommercial varieties). These patterns are likely driven by the combination of repeated genetic bottlenecks, strong artificial selection, and increased inbreeding that humans have intentionally and unintentionally applied during the process of domestication.”

Looking at the big picture when it comes to urban wildlife conservation

It may be useful to evaluate surrounding green spaces and their connectivity when creating urban wildlife habitat. A study done in Syracuse, NY in 1986 found that many mammal species don't just stay within one habitat type, but instead use a mosaic of spaces for varying needs. The researchers found that by studying the variables found within a regional area were more important than site specific landscapes. The area of water, amount of paving, grass area, and green space amounts were more important than classes of trees or amount of understory. The authors conclude that urban animals use a regional approach for habitat needs than individual site provisions.

Good ag neighbors: Rare remnant plant species are better conserved in larger forest patches next to ag lands than urban

Because of publisher copyright restrictions I can't share the research abstract, however I can summarize an interesting study in 2006 that found that agricultural lands are better neighbors than urban land use that adjoin remnant woodlots. The study that was done in Spain found that plant species recorded were compared to levels of human disturbance and frequency. Results were determined that disturbance-type plant species decreased with increasing distance to forest edge. Rare forest species were richer in large patches adjacent ag-based lands as compared to small woodland patches in peri-urban areas.

New Study Shows Vegetation Controls the Future of the Water Cycle

“Plants are really the thermostat of the world,” says Léo Lemordant, Gentine’s PhD student and lead author of the paper. “They’re at the center of the water, energy, and carbon cycles. As they take up carbon from the atmosphere to thrive, they release water that they take from the soils. Doing that, they also cool off the surface, controlling the temperature that we all feel. Now we know that mainly plants—not simply precipitation or temperature—will tell us whether we will live in a drier or wetter world.”

Their study“Critical impact of vegetation physiology on the continental hydrologic cycle in response to increasing CO₂.”is published in Proceedings of the National Academy of Sciences. Authors are: Léo Lemordant (Columbia Engineering); Pierre Gentine (Columbia Engineering and Earth Institute); Abigail Swann (University of Washington); Benjamin I. Cook (NASA Goddard Institute for Space Studies and Lamont-Doherty Earth Observatory, Columbia University); and Jacob Scheff (University of North Carolina, Charlotte).

Compact urban development with large open spaces slows bird declines

"We show that urban growth of any type reduces bird distributions overall, but compact development substantially slows these reductions at the city scale."

Sushinsky et al evaluated the changes in bird populations between sprawling cities and dense, compact cities. They found that while all urban growth reduces overall bird density but that compact cities have slower declines. In their 2012 Global Change Biology journal article that "Our results suggest that cities built to minimize per capita ecological impact are characterized by high residential density, with large interstitial green spaces and small backyards, and that there are important trade‐offs between maintaining city‐wide species diversity and people's access to biodiversity in their own backyard."

Sushinsky, J. R, Rhodes, J. R., Possingham, H. P., Gill, T. K. and Fuller, R. A. (2013) How should we grow cities to minimize their biodiversity impacts? Global Change Biology 19, 401–410.

Temporary wetlands are important too

Urban and Roehm's research on studying temporary wetlands and associated species was published in the January 2018 Oecologia. It observesthat exurban ponds tend to be designed and managed as permanent waterbodies which retain permanent wetland species but fewer temporary wetland types.

Swamp Forest Exhibit at Crosby Arboretum was designed as a temporary stream corridor

"Exurban areas are expanding throughout the world, yet their effects on local biodiversity remain poorly understood. Wetlands, in particular, face ongoing and substantial threats from exurban development. We predicted that exurbanization would reduce the diversity of wetland amphibian and invertebrate communities and that more spatially aggregated residential development would leave more undisturbed natural land, thereby promoting greater local diversity. Using structural equation models, we tested a series of predictions about the direct and indirect pathways by which exurbanization extent, spatial pattern, and wetland characteristics might affect diversity patterns in 38 wetlands recorded during a growing season. We used redundancy, indicator species, and nested community analyses to evaluate how exurbanization affected species composition. In contrast to expectations, we found higher diversity in exurban wetlands. We also found that housing aggregation did not significantly affect diversity. Exurbanization affected biodiversity indirectly by increasing roads and development, which promoted permanent wetlands with less canopy cover and more aquatic vegetation. These pond characteristics supported greater diversity. However, exurbanization was associated with fewer temporary wetlands and fewer of the species that depend on these habitats. Moreover, the best indicator species for an exurban wetland was the ram’s head snail, a common disease vector in disturbed ponds. Overall, results suggest that exurbanization is homogenizing wetlands into more permanent water bodies. These more permanent, exurban ponds support higher overall animal diversity, but exclude temporary wetland specialists. Conserving the full assemblage of wetland species in expanding exurban regions throughout the world will require protecting and creating temporary wetlands."

Abstract cited from: Urban, M.C. & Roehm, R. Oecologia (2018) 186: 291. https://doi.org/10.1007/s00442-017-3989-y

CO2 sensor network shows effects of metro growth

“In a study published today in Proceedings of the National Academy of Sciences, a team led by atmospheric scientists Logan Mitchell and John Lin report that suburban sprawl increases CO2 emissions more than similar population growth in a developed urban core.

“The general thought is that more compact cities on a per capita basis emits less carbon,” Lin says. “Some of these cities also have these expanding fringes. These places are less ‘green’, so to speak. That expanding frontier is moving.””

Published in https://unews.utah.edu/u-co2-sensor-network/

Green spaces in cities help control floods, store carbon

Abstract: "Urban landscapes are increasingly recognized as providing important ecosystem services (ES) to their occupants. Yet, urban ES assessments often ignore the complex spatial heterogeneity and land-use history of cities. Soil-based services may be particularly susceptible to land-use legacy effects. We studied indicators of three soil-based ES, carbon storage, water quality regulation, and runoff regulation, in a historically agricultural urban landscape and asked (1) How do ES indicators vary with contemporary land cover and time since development? (2) Do ES indicators vary primarily among land-cover classes, within land-cover classes, or within sites? (3) What is the relative contribution of urban land-cover classes to potential citywide ES provision? We measured biophysical indicators (soil carbon [C], available phosphorus [P], and saturated hydraulic conductivity [Ks]) in 100 sites across five land-cover classes, spanning an ~125-year gradient of time since development within each land-cover class. Potential for ES provision was substantial in urban green spaces, including developed land. Runoff regulation services (high Ks) were highest in forests; water quality regulation (low P) was highest in open spaces and grasslands; and open spaces and developed land (e.g., residential yards) had the highest C storage. In developed land covers, both C and P increased with time since development, indicating effects of historical land-use on contemporary ES and trade-offs between two important ES. Among-site differences accounted for a high proportion of variance in soil properties in forests, grasslands, and open space, while residential areas had high within-site variability, underscoring the leverage city residents have to improve urban ES provision. Developed land covers contributed most ES supply at the citywide scale, even after accounting for potential impacts of impervious surfaces. Considering the full mosaic of urban green space and its history is needed to estimate the kinds and magnitude of ES provided in cities, and to augment regional ES assessments that often ignore or underestimate urban ES supply."

Ziter, C. and Turner, M. G. (2018), Current and historical land use influence soil-based ecosystem services in an urban landscape. Ecological Applications. doi: 10.1002/eap.1689

New York Metropolitan Flora project

In 1990 the Brooklyn Botanic Garden embarked on the New York Metropolitan Flora project (NYMF), a multiyear effort to document the flora in all counties within a 50-mile radius of New York City, including all of Long Island, southeastern New York State, northern New Jersey and Fairfield County, Connecticut. Garden staff collect woody plant data and have created an online encyclopedia that shows plant data and maps of the New York metro region. For more on this project or to view the encyclopedia, visit https://www.bbg.org/collections/nymf