The world’s population is concentrated in urban areas. This change in demography has brought landscape transformations that have a number of documented effects on stream ecosystems. The most consistent and pervasive effect is an increase in impervious surface cover within urban catchments, which alters the hydrology and geomorphology of streams. This results in predictable changes in stream habitat. In addition to imperviousness, runoff from urbanized surfaces as well as municipal and industrial discharges result in increased loading of nutrients, metals, pesticides, and other contaminants to streams. These changes result in consistent declines in the richness of algal, invertebrate, and fish communities in urban streams. Although understudied in urban streams, ecosystem processes are also affected by urbanization. Urban streams represent opportunities for ecologists interested in studying disturbance and contributing to more effective landscape management.

/pdf/streams-in-the-urban-landscape-mt89v53ix5.pdf

Streams in the Urban Landscape

https://usir.salford.ac.uk/9497/1/Tzoulas_et_al_2007.pdf

Promoting ecosystem and human health in urban areas using Green Infrastructure: A literature review

Many studies have described the effects of urbanization on species richness. These studies indicate that urbanization can increase or decrease species richness, depending on several variables. Some of these variables include: taxonomic group, spatial scale of analysis, and intensity of urbanization. Recent reviews of birds (the most-studied group) indicate that species richness decreases with increasing urbanization in most cases but produces no change or even increases richness in some studies. Here I expand beyond the bird studies by reviewing 105 studies on the effects of urbanization on the species richness of non-avian species: mammals, reptiles, amphibians, invertebrates and plants. For all groups, species richness tends to be reduced in areas with extreme urbanization (i.e., central urban core areas). However, the effects of moderate levels of urbanization (i.e., suburban areas) vary significantly among groups. Most of the plant studies (about 65%) indicate increasing species richness with moderate urbanization whereas only a minority of invertebrate studies (about 30%) and a very small minority of non-avian vertebrate studies (about 12%) show increasing species richness. Possible explanations for these results are discussed, including the importance of nonnative species importation, spatial heterogeneity, intermediate disturbance and scale as major factors influencing species richness.

Effects of urbanization on species richness: A review of plants and animals

Classifying and valuing ecosystem services for urban planning

Urban forests and pollution mitigation: analyzing ecosystem services and disservices.

https://www.kth.se/social/upload/4ea53de1f27654240a000000/Bolund%20and%20Hunhammar%201999.pdf

Ecosystem services in urban areas

This paper discusses in general terms the potential risk that increased recycling of materials in the technosphere may lead to significant changes in freight transportation demands. Such cyclic, as opposed to linear, material flows are proposed as one step towards an environmentally sustainable use of resources. Total volume of transported annual material flows in Sweden are estimated in order to provide a background for the analysis of transport demands: • Raw material 210 Mton • Products 165 Mton • Residues from production 20 Mton • Residues from consumption 10 Mton The difference in volume between raw material and products is explained by foreign trade, generation of residues and indefinite data. The difference in products compared to residues can primarily be explained by an increasing stock of materials in society, large pollution flows (e.g., CO 2 ), and that resources have a higher water content than residues. On a qualitative basis, it can be argued that a drastic increase of transportation demand can not be expected by increased recycling. A decrease of transported raw material is expected for some sectors, while only limited increase of residue transports. Furthermore, it should also be observed that the problem of residue/waste transportation is very small compared to the environmental impact of the total transportation sector. The main conclusion is therefore that the expected changes in transportation demand due to increased reuse and recycling, are not a general hindrance against introducing a more cyclic material management.

Sven Hunhammar

Papers

Ecosystem services in urban areas

Cycling residues. Potential for increased transportation demands due to recycling of materials in Sweden