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.