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