Rewilding in the Garden: are garden hybrid plants (cultivars) less resilient to the effects of hydrological extremes than their parent species? A case study with Primula Abstract Urban green infrastructure, such as gardens, can mitigate some of the consequences of climate change, e.g. reducing flash-flooding or urban heat islands. Green infrastructure, however, may itself be vulnerable to a changing climate, and not all garden and landscape plant taxa will remain viable under weather scenarios predicted for the future. It has been suggested that cultivated forms of garden plants (hybrids and selected varieties) particularly, will be susceptible to enhanced stress associated with more frequent flooding, drought and rapid oscillations between these hydrological extremes; thus potentially limiting the range of taxa that can be used in gardens in the future. This research explored this concept by evaluating cultivated forms of the common garden plant – Primula, and testing whether these were less resilient to the effects of hydrological extremes than their progenitor species, Primula vulgaris. The results support this hypothesis and demonstrated that cultivated taxa were more susceptible to the hydrological stresses imposed than Primula vulgaris. Interestingly though, those cultivars that superficially resembled the parent species (Primula ‘Cottage Cream’) showed more stress tolerance than others with larger or more ornamental flowers, suggesting a ‘gradient of susceptibility’ within the hybrids. The notion that the most flamboyant cultivars are sacrificing stress tolerance for traits linked with aesthetics is discussed. The data, albeit on one genus only, has implications for the design of gardens/ornamental landscapes for the future and calls for more attention within breeding programmes to enhance abiotic stress tolerance within garden and landscape plants.

Biodiversity conservation in urban parks: a study of ground-dwelling ants (Hymenoptera: Formicidae) in Rio de Janeiro City Abstract Urban green recreational spaces may provide habitat for animals and plants. We investigated the importance of urban public parks in the city of Rio de Janeiro with regard to the conservation of ant species by comparing both the structure of the ground-dwelling ant community between urban parks and continuous forests and the influence of environmental factors on possible differences. Fifteen urban areas were sampled (5 isolated parks, 5 non-isolated parks and 5 forest areas). Ants were sampled at sardine bait stations and through manual/visual searching in quadrats around the baits. We identified 120 ant species (4 exotic species) distributed across 38 genera and 7 subfamilies. The four exotic species were Monomorium floricola, Paratrechina longicornis, Pheidole megacephala and Tetramorium simillimum. Both the taxonomic and functional diversity of ground-dwelling ants were higher in continuous forests, followed by non-isolated and then isolated urban parks. Environmental factors were found to be key drivers influencing the differences in ant community structure among continuous forests and urban parks. Soil compaction and canopy cover predicted the diversity patterns of the taxonomic and functional compositions of the ant communities. The ant species in the study areas exhibited a non-random pattern of distribution and a spatial association of species segregation. There was high spatial turnover of ant species in the study areas, indicating that conservation efforts are required in all studied urban areas, not just those areas considered to be species rich. Therefore, we need to conserve more species in more areas, not necessarily those high in richness.

Conservation and enhancement of the green infrastructure as a nature-based solution for Rome’s sustainable development Abstract Three quarters of the European population live in urban areas, which is expected to increase to over 80% by 2050. The well-being of urban citizens appears to be closely linked to the correlation between the growth of urban areas and to the availability of green spaces. The conservation and the enhancement of the Green Infrastructure (GI) can be considered a Nature-Based Solution (NBS) to improve the sustainability of urban development. From this perspective, it is important to identify priority areas close to existing GIs suitable to be preserved from further urban encroachment. Our study aims to draw up a methodology to identify priority areas and, accordingly, to expand the GIs. The main objectives are: (i) to identify the most sensitive areas of the GI to be preserved from urban encroachment; (ii) to locate arable lands in the vacant border territories between GIs and built-up areas, that, if converted into connected elements, would enhance the connectivity of the existing GIs whilst limiting land take; (iii) to define an index of priorities for increasing the GI territory by means of NBSs, taking into account the variability of GI coverage and level of legal protection for nature conservation across different neighborhoods in the city. This approach is applied to the GIs of the 15 administrative units of the municipality of Rome (Italy) as a case study. First, we focus on Urban Atlas classes to map the GIs in the municipality. We then use Morphological Spatial Pattern Analysis, implemented by a free software toolbox GUIDOS, to identify the key components of the GIs, such as hubs (core areas) and links (bridges). Then, a simulated new scenario is provided by including within the current GIs the agricultural lands outside protected areas, but within a buffer zone of 300 m from the land take. If the aforementioned agricultural lands, amounting to about 8000 ha, were converted into GI elements, they could lead to the improvement of connectivity and limit land take. Finally, in order to expand the area of the GIs, priority areas are selected within each administrative unit using an index based on the budget allocation process. The proposed methodology could be used: (i) by decision makers, looking for NBS in the design and planning of sustainable development of the city; and (ii) to enhance GI connectivity.

Evaluating the potential contribution of urban ecosystem service to climate change mitigation Abstract Promoting urban greenery through tree planting strategies has been considered as a measure to mitigate climate change. While it is essential to understand the temporal dynamics of urban forest structure as well as its services and contribution to human wellbeing in cities, it has hardly ever been examined whether the future contributions of these services after different possible planting strategies can comply with climate change policy goals; these are topics rarely discussed in urban planning and management. In this paper, the ecosystem services currently provided by urban trees (through carbon sequestration and storage), as well as those potentially provided in the future, were quantified using the i-Tree Eco model, and their contribution to climate change mitigation was evaluated. As a case study in Tabriz, Iran, we developed four possible scenarios. Synergy (urban temperature regulation by UF) and trade-off (tree water requirements) were also analyzed. Future carbon sequestration and storage potential of urban trees was compared with the estimated future carbon emissions. The current contribution in Tabriz is relatively modest (about 0.2%), but it can be tripled through long-term tree planting strategies. Additionally, the temporal cooling effects and tree water requirements increase as climate change mitigation improves through tree planting. We conclude that urban tree planting has a small impact on carbon mitigation in the study area, most likely because of the young age of trees in Tabriz as well as the fact that the planted trees cannot deliver all their benefits over a 20-years period and need more time. Thus, the use of urban trees serves only as a complementary solution rather than an alternative climate mitigation strategy. Our quantitative approach helps urban environmental policymakers to evaluate how much they can rely on urban forest strategies to achieve climate change mitigation targets.

Effects of demography and urbanization on stress and body condition in urban white-tailed deer Abstract White-tailed deer (Odocoileus virginianus) are becoming increasingly common in urban environments. How they respond to potential changes (i.e. increased human interactions, traffic, overabundance) can influence herd health. We aimed to develop a technique that quantifies stress in deer using hair cortisol concentrations (HCC). Our objectives were to test for: 1) a relationship between HCC and deer body condition score (BCS); 2) effects of sex, age, and location on HCC; and 3) effects of herd density and urbanization on HCC. Using the HCC of 59 culled deer from 8 sites (Cook County, IL USA), of which 7 sites were part of yearly herd management to maintain population sizes (site was managed) and 1 site was not (un-managed), we found deer with the poorest BCS had the highest HCC (P < 0.01). We then compared HCC from 342 deer, from 24 managed sites in 4 counties (IL, USA), to test for the effects of biological and environmental factors. Results showed sex and age did not influence HCC (sex; P = 0.13, age; P = 0.18), while site location did (P < 0.01). We then modeled HCC from the 24 managed sites as a function of two site variables that could influence HCC: herd density (deer/km2) and urbanization (presence of roads, buildings, vegetation), and found neither had a significant effect. In conclusion, HCC is correlated to BCS and is a non-invasive metric of health. Herd density, if left unmanaged (Objective 1), is a more important driver of individual health than degree of urbanization.

Differences in fish harvest, fishing effort, and angling guard activities between urban and natural fishing grounds Abstract Recreational fishing is a very popular outdoor leisure activity. Assessing differences in basic metrics in recreational fishing on different types of fishing grounds is very important for effective fisheries management. This study aimed to discover how basic metrics in recreational fishing (harvest, fishing effort, angling guard activities) differ between urban fishing grounds (located in a densely populated city) and natural fishing grounds (located in the countryside). Data were obtained from individual angling logbooks collected by the Czech Fishing Union on the River Elbe and the River Vltava (Prague and Central Bohemia, Czechia, Central Europe). Study shows that urban and natural fishing grounds showed significant differences in basic metrics in recreational fishing. Urban fishing grounds displayed higher fish harvest in general and higher dominance of intensively stocked fish species in catches of anglers (mainly common carp Cyprinus carpio). High harvest rates of common carp can be mostly explained by intensive fish stocking. The only fish species that showed higher harvest on natural fishing grounds were large-growing piscivorous fish with high ecological demands. However, anglers were harvesting larger fish (average body weight) on natural fishing grounds. In addition, fishing effort was similar on both types of fishing grounds. Inversely, angling guards were more active on natural fishing grounds. In conclusion, differences in basic fisheries metrics between urban and natural fishing grounds seem to be partially driven by intensive fish stocking.

Increase in non-native species richness leads to biotic homogenization in vacant lots of a highly urbanized landscape Abstract Vacant lots, unused lands covered by spontaneous vegetation, are widespread in urban landscapes. Although they are of less conservation value than natural ecosystems, they can provide important ecological services, such as maintaining air quality and mental health, and offering recreational space. Nevertheless, the effects of urbanization on the plant species richness and beta diversity of such lots remain poorly understood. We evaluated how plant species richness and beta diversity differ in vacant herbaceous lots 1) between two urban areas (Montréal and Québec, Canada) characterized by contrasting urbanization intensity, and 2) along a rural-urban gradient within both landscapes. We inventoried 69 vacant lots in Montréal and 62 in Québec distributed along three local levels of urbanization (established using NDVI values in a 500 m buffer zone around each lot). We found a lower beta diversity for plant communities in vacant lots in the most urbanized landscape (Montréal) compared to the least urbanized one (Québec), but no effect of local level of urbanization intensity in either of the landscapes. Montréal was richer than Québec in regard to non-native species, while native richness was similar between the two landscapes. Non-native richness was higher than that of natives at each local level of urbanization intensity, and the highest at moderate urbanization intensity. Finally, non-native species were functionally more homogenous than natives both within and between landscapes. Overall, our results suggest that biotic homogenization occurr only in very urbanized landscapes and that this homogenization results from non-native species invasion without local native extirpation.

High tick abundance and diversity of tick-borne pathogens in a Finnish city Abstract The sheep tick Ixodes ricinus is the primary vector for various zoonotic diseases, including Lyme borreliosis and tick-borne encephalitis (TBE), in Europe. Because both abundance of ticks and prevalence of tick-borne pathogens in these organisms have increased in many locations and under different environments, we designed a study to survey the occurrence of ticks and pathogens in an urban area, namely, the city of Turku, in SW Finland. In summer 2017, we collected >700 ticks, primarily from city parks, suburban forest patches, and recreational areas. Comprehensive subsets of ticks were screened for presence of all common tick-borne pathogens. Half of the ticks carried at least one pathogen. The most common pathogens detected were the causative agents of Lyme borreliosis, i.e., bacteria belonging to the Borrelia burgdorferi sensu lato group. Their prevalence was 37% in nymphal and 47% in adult ticks, which are high in comparison with surveys conducted elsewhere in northern Europe. Similarly, Rickettsia spp. (primarily R. helvetica) were also detected in a relatively high proportion of the samples (11% of both nymphs and adults). The TBE virus was not found in a relatively small subsample, but we detected (albeit at a low prevalence of 0–6% of nymphs and adults) the bacterial pathogens Borrelia miyamotoi, Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis and the protozoan Babesia spp., which are also known agents of zoonotic diseases. The relatively high abundance of ticks and high diversity and overall prevalence of tick-borne pathogens suggest a lively and dense presence of mammalian and avian tick hosts in the city. Our results indicate a higher risk of encountering tick-borne pathogens in urbanized areas of southern Finland than previously known. Moreover, the possibility of acquiring tick-borne diseases from urban environments likely exists throughout most of Europe, and it should be acknowledged by health care professionals.

Urbanization decreases the extent and variety of leaf herbivory for native canopy tree species Quercus rubra , Quercus alba , and Acer saccharum Abstract The extent to which urban trees can support associated biodiversity and provide ecosystem services depends on how urbanization affects the relationship between plants and the herbivorous arthropods that feed on them. Previous studies suggest that urbanization tends to increase the abundance, but decrease the diversity of herbivorous arthropods, but also reveal that this pattern may be an artifact of a narrow focus on pests and ornamental plants. We aimed to assess the effect of urbanization on whole leaf herbivore communities of three native canopy trees, red oak (Quercus rubra), white oak (Quercus alba), and sugar maple (Acer saccharum). For each species we compared the extent of herbivory (assessed as percent leaf loss) and diversity of herbivores (using the number of identifiable damage types as a proxy for feeding guild diversity) between sites in southeast Michigan that were more forested vs. more urbanized (with lower tree density and canopy coverage and higher percent hardscape and turf). We found that across all three species and sites compared, both the percent leaf area lost to herbivory and the number of different types of herbivory were consistently and significantly higher in forested than urbanized sites. While future studies are needed to confirm the mechanisms responsible, we conclude that at least for native canopy tree species, trees in more urbanized sites do not appear to experience higher herbivory, and instead support diminished herbivore communities compared to the same trees in a more forested setting.

A tale of two cities, with bears: understanding attitudes towards urban bears in British Columbia, Canada Abstract The management of black bears (Ursus americanus) in urban and/or exurban settings is of growing concern as these mammals, along with coyotes, cougars and others, begin to re-colonize areas from which they had been extirpated. Urban and exurban landscapes can offer much needed habitat to these space-demanding creatures, thereby buffering habitat losses in other areas and protecting populations of these species, but only if conflicts between these animals and humans can be managed and minimized. In the case of urban black bears, they can become quickly labled as a “problem” bear if they become too reliant on human garbage or other food sources such as fruit trees. A “problem” bear usually becomes a dead bear. In collaboration with the Northern Bear Awareness Society in Prince George, British Columbia, Canada, UNBC researchers undertook two surveys of Prince George over a 3 year period and a companion survey in the city of Coquitlam, BC to examine attitudes towards urban bears. The research found that residents of both cities, in spite of regular and close encounters with black bears, strongly supported the presence and preservation of bears within an urban setting, largely due to conservation concerns. Both communities were supportive of non-lethal control of “problem bears” and supported the use of warnings and fines to discourage human behaviors that created human-bear conflicts over lethal controls. These findings offer support for municipal governments to reconsider approaches to urban bear management.