Effects of long-term landscape dynamics and city growth on biodiversity in the Mediterranean: the case study of Montpellier,France

In the Mediterranean, long-term land-use changes have resulted into landscape mosaics composed of very few ancient woodland remnants scattered across extended post-agricultural woodlands. Patches of ancient woodlands are now suffering rapid urban growth that reduces their area and impact their associated biodiversity. Here we use the case study of Montpellier, one of the most dynamic cities in France, to 1) characterize temporal changes in land covers (between 1860 and 2006) in its area, and 2) using two guilds of fungal bioindicators (i.e., polypores and lichens), to compare biodiversity stakes between ancient and secondary Mediterranean woodlands. We used a combination of historical maps, archives, fungal collections and field survey in eight Quercus ilex patches (4 ancient versus 4 recent replicates) to reconstruct landscapes dynamics and assess biodiversity changes. From the 19th to the 21st century, over half (52.4%) of the ancient woodlands within Montpellier were replaced by other land covers, mainly by urban equipment, while secondary patches (16.8% of the total area) were naturally established. Remaining ancient woodlands show multi-layered vegetation made of multi-secular Pinus halepensis dominating a dynamic understorey made of Quercus ilex and various Mediterranean shrubs. Polypores, but not macrolichens, tended to differ in community composition between ancient and recent woodland patches, with the highest diversity found in ancient woodlands. This study highlights that urban woodland patches of contrasted histories harbour distinct biodiversity stakes to be included in urban planning and provide valuable areas to evaluate biodiversity patterns and dynamics.     

Seasonal patterns of urban bird diversity in a Mediterranean coastal city: the positive role of open green spaces

Urban Ecosystems - Urbanization causes rapid changes in the landscape and land use, exerting a significant pressure on bird communities. The effect of urbanization on bird diversity has been widely...     

Forest bird communities across a gradient of urban development

This study examined native bird communities in forest patches across a gradient of urbanization. We used field data and multivariate statistical techniques to examine the effects of landscape context, roads, traffic noise, and vegetation characteristics on bird community composition in the North Carolina Piedmont (U.S.A.). Landscape-level variables, particularly those related to urbanization, were most important in structuring forest bird communities. Specifically, we found that road density and amount of urban land cover were the best predictors of species composition. We found that urban and rural bird communities were quite distinct from each other. Rural communities had more long-distance migrants and forest interior species but species richness did not differ between the communities. Our results suggest some specific guidelines to target bird species of interest both inside and outside of urban areas. For example, if increasing numbers of migratory species is of primary concern, then conservation areas should be located outside of urban boundaries or in areas with low road density. However, if maximizing species richness is the focus, location of the conservation area may not be as important if the conservation area is surrounded by at least 50 m of forest habitat in all directions.     

Influence of urban landscape structure on bird fauna: a case study across seasons in the city of Valencia (Spain)

Studies on bird fauna of urban environments have had a long history, but the potential of studies mapping the distribution of birds in cities probably has not fully developed. The bird fauna of the municipality of Valencia (Spain) was studied to determine the influence of urbanization on bird species richness and abundance. Birds were censused during winter and the breeding season of years 1997–1998 in 197 squares measuring 49 ha each from a rural and an urbanized area. Across seasons the number of species decreased around 40% in the city compared with the rural landscape surrounding it. Such pattern could be attributed to the low number of farmland species capable to use the habitats inside the city, and the limited ability of urban parks in attracting woodland species. In the urban landscape, the influence of the dimensions and spatial arrangement of habitat patches was outweighed by the amount of each habitat per square. Bird richness and the abundance of most species were negatively related with the amount of built-up habitat per square and positively with the amount of urban parks, and of habitat diversity. Conversely, bird fauna was largely independent of mean park size per square especially during winter, indicating that at the landscape scale even small patches of habitat could play an ecological role. Conservation of urban bird diversity could benefit of two complementary strategies: (i) the protection of the surrounding rural landscape from urban development; (ii) habitat enhancement within the city. Particularly, a proper design and habitat management of urban parks could improve their suitability for urban bird fauna.     

Variability of bumblebee communities (Apidae,Bombini) in urban green areas

Based on current research the agglomerations are potentially desirable habitats for bumblebees. However, the relationship between the biodiversity of these bees and the green areas where they live is poorly understood. The aim of the study was to estimate the influence of green areas (ranging from 8 to 102 ha) of big cities on bumblebee species richness, composition, and the relative number of these insects. The studies were conducted within the administrative borders of the city of Wroc?aw (Poland) in 2011–2012 in 12 green areas such as parks, cemeteries and other places with trees and shrubs. Species richness and abundance of bumblebees was determined by direct observation during 30 min. The gathered materials were used to calculate how areas of urban green space affected qualitative and quantitative bumblebee community structure. In total, 13 species of bumblebees (Bombus Latr.) were recorded, of which 3 belonged to cuckoo bumblebees (Psithyrus subgenus). The share of the most similar groups was congregated in green areas not smaller than 30 ha. This was proved by analysis of qualitative structure (Sørensen index), quantitative structure (Renkonen index), and qualitative-quantitative structure (Cody’s index). The number of bumblebee species in the surveyed green areas (r = 0.7497) was decisive for the arrangement of the mutual similarity of group structure. Green urban areas should be created in a size of at least 30 ha. Such sites provide conditions for the most diversified bumblebee species communities. Sites smaller than 30 ha can play an important role as refuges, and allow migration to all pollinators.     

The influence of urban park characteristics on ant (Hymenoptera, Formicidae) communities

As rapid urbanization continues, existing natural areas within urban zones will play a critical role in safeguarding remaining biodiversity. Ants are an integral part of almost every terrestrial ecosystem, including urban environments, and understanding which environmental characteristics influence their persistence is critical. In this study, 24 protected natural areas within urban parks including mosaic, scrub, herbaceous and forest habitats were surveyed for ants with 563 pitfall traps. The data provide insights into the distribution and abundance of ant fauna in San Francisco natural areas, as well as which characteristics of parks have the most influence on ant community composition. A total of 2,068 ant individuals representing 15 species were collected. A regression analysis revealed that urban forests reduced ant richness and abundance and that there was little or no impact of the Argentine ant on native ants. Natural area size and shape were not important in explaining variations in overall ant species richness and abundance, with many smaller natural areas harboring ant populations that are just as diverse and robust as larger areas.     

The effects of trampling on assemblages of ground beetles (Coleoptera,Carabidae) in urban forests in Helsinki,Finland

The occurrence of carabid beetles in relation to trampling was examined in urban forest sites located in the city of Helsinki, southern Finland. The degree of wear of the forest floor was assessed and used as a measure of trampling intensity. In particular, we examined the following predictions: (1) carabid diversity should decrease with increasing trampling intensity, (2) mean body size of the dominating carabid species should decrease with increasing trampling intensity, and (3) opportunistic species should gain dominance in severely trampled sites. In total, 1,326 beetles representing 27 species were captured. The first prediction was not supported, as there was no correlation between species richness or Hill's N2 diversity index and trampling intensity. However, there was a positive correlation between number of carabids captured and trampling intensity of the site. The second hypothesis gained some support, as there was a marginally significant negative correlation between body size and trampling intensity. The hypothesis that opportunistic species should gain dominance in severely trampled sites was supported as one species was very dominant (Pterostichus melanarius, 60.0%) in the heavily trampled sites, while there were two equally and less dominant species in the less trampled sites. Individual species did show different responses to the effects of trampling, and the most sensitive forest species may not survive in the heavily trampled sites. We conclude that at the community level (e.g., species richness, diversity), the effects of trampling on carabids in urban forests are subtle, but impacts are pronounced for some sensitive species.     

How Cortaderia selloana,an ornamental plant considered highly invasive,fails to spread from urban to natural habitats in Southern France

Urban Ecosystems - The role of urban areas in the introduction of alien plant species, and their subsequent spread in the countryside, has long been identified. However, it was mainly considered...     

The roles of mosquito and bird communities on the prevalence of West Nile virus in urban wetland and residential habitats

This study investigated the impacts of urban wetlands and their adjacent residential environments on the transmission dynamics of West Nile virus (WNV) within the state of New Jersey (USA). A working hypothesis was that urban wetlands decrease the local prevalence of WNV through the dilution effect from increased bird diversity, and through relative reductions in the numbers of competent avian host and mosquito species commonly associated with WNV. Surveys of mosquito and bird communities were undertaken at six urban wetlands and their adjacent residential environments over two seasons (2009, 2010). The community compositions of both avian and mosquito species differed significantly across habitats, and over relatively short geographical distances. Residential areas contained significantly higher proportions of WNV-competent mosquito species (31.25?±?5.3?%; e.g. Culex pipiens and Culex restuans), and WNV-competent avian host species (62.8?±?2.3?%, e.g. House Sparrow and American Robin) when compared to adjacent urban wetlands (13.5?±?2.1?%; 35.4?±?2.1?% respectively). Correspondingly, WNV infection rates within local Culex spp. populations indicate that WNV was more prevalent within residential areas (28.53/1000) compared to wetlands (16.77/1000). Large urban wetlands (>100?ha) produced significantly lower weekly WNV infection rates in local Culex spp. (6.67?±?2.84/1000) compared to small (<15?ha) wetlands (22.57?±?6.23/1000). Avian species richness was also influenced by patch size. Large urban wetlands contained significantly more species than small wetland patches. These results confirm that the community compositions of mosquito and avian hosts are important drivers in WNV infections, and that the ecological conditions that favor transmission are more strongly associated with urban residential environments than with adjacent urban wetlands.     

Novel woodland patches in a small historical Mediterranean city: Padova,Northern Italy

Urban Ecosystems - Woodland fragments, in small historical cities, are commonly regarded as temporary voids in an urban matrix, yet to be allocated a land-use, under city planning regulations....     

The Politics of Seasonal Labour Migration in Switzerland,France and Spain

This article analyses the effects of the politics of seasonal foreign worker admissions on migrant legality in the context of the post‐1945 and the post‐1990 seasonal foreign worker policy in Switzerland, France and Spain respectively. It seeks historical evidence attesting to the ability of seasonal admissions to restrict workers to their non‐resident status. It presents implications for circular migration, the dernier cri in European migration policy aimed to strike a compromise between a perceived post‐crisis demand for the admission of foreign workers and the reluctance to make them prospective citizens.

Policy Implications

• Migration policy stakeholders have shaped foreign worker admissions according to their interests.
• Under some conditions, low‐skilled seasonal foreign worker admissions have contributed to irregular migration, either through workers' overstays or through parallel irregular entries
• There are both differences and similarities between the seasonal admissions advocated under the post‐2007 circular migration schemes, and those of the 1950s–1960s, as well as those of 1990s to early 2000s. The similarities could, under some conditions, trigger the repetition of some of the unexpected outcomes revealed by historical seasonal foreign worker admissions under the post 2007 schemes.

     

A comparison of Mediterranean Gecko (Hemidactylus turcicus) populations in two temperate zone urban habitats

Urban ecosystems represent unique habitats that might be more or less suitable than natural systems for many species. The Mediterranean Gecko, Hemidactylus turcicus is a synanthropic species that has successfully colonized many urban and suburban areas outside its natural range. In the United States, H. turcicus has been found predominantly in southern states on exterior surfaces of buildings. We compared population density, demographics, and extent of dispersal of populations of H. turcicus at two anthropogenic sites in a temperate region of the United States. The University of Central Oklahoma (UCO) had higher building density and greater cover by anthropogenic surfaces and the Oklahoma City Zoo (ZOO) had lower building density and greater cover by vegetation. Mark and recapture sampling was conducted at UCO from 2006 to 2007 and during 2008 at ZOO. The sizes of the populations at the two sites were estimated using the Schnabel method and population densities were calculated using those estimates. Age class of captured animals, sex of adults, and gravid status of adult females were determined at both sites. We assumed that greater exterior wall surface area of individual buildings at UCO and greater land cover by anthropogenic surfaces might 1) reduce population density and 2) facilitate dispersal there relative to the ZOO. Population sizes and density in animals per ha of land and building cover and demographics were similar at the two sites. Population density per ha of building exterior wall area was higher at ZOO than at UCO. The higher density of animals on buildings, lower proportion of subadults in the population and lower maximum dispersal distance at ZOO suggest that successful diffusion dispersal might be limited at that site relative to UCO.     

Seasonal comparisons of daily activity budgets of gray squirrels (Sciurus carolinensis) in urban areas

Gray squirrels (Sciurus carolinensis) use trees for various resource needs in urban and nonurban settings; particularly, mast producing trees which are the preferred and supplemental foods for the species. During periods of abundant mast availability, less time will be invested in foraging because of the higher success rate stemming from the increased ability to locate food items. Conversely, in periods of reduced mast availability, more time will be invested in foraging. However, correlations between food availability and foraging effort are only supported under the assumption that gray squirrels rely significantly on mast as a preferred or supplemental food source (Nixon et al, J Wildl Manag 39:1–25, 1975). Therefore, given the seasonal variation in the availability of mast, there should also be correlating seasonal variations in foraging effort. In this paper, we will examine daily and seasonal time-activity budgets of gray squirrels in urban areas. We studied the time-activity budgets of gray squirrels in six urban parks in Baltimore, MD. Seasonal frequencies of activities were expressed as percent occurrence and seasonal differences in activities were analyzed using a Tukey Studentized multiple range test for significance. We found that the activity with highest percent occurrence was forage (2003, summer: 23.8 %, fall: 25.9 %; 2004, summer: 23.1 %, fall: 25.2 %), followed by feed and store, all activities associated with food. Results of the Tukey Studentized multiple range test for seasonal differences of activities yielded significant results (P?P?=?0.003); fall 2003 and fall 2004 (P?=?0.048).     

Home gardening practice in Pune (India), the role of communities,urban environment and the contribution to urban sustainability

Urban Ecosystems - Urban agriculture (UA) is regarded as an emerging tool and strategy for sustainable urban development as it addresses a wide array of environmental, economic and social...     

From nightlife conventions to daytime hidden agendas: dynamics of urban sexual territories in the South of France

This article focuses on the space-time dynamics of sexual encounters in city neighborhoods associated with sex work and cruising. The data were collected as part of a multisite, longitudinal ethnographic study conducted in major cities of southern France. The results suggest that there is a continuous interaction between these sexualized public spaces and urban planning. Urban planners, however, are not the only actors shaping the location and the use of the space. Participants create a dialectical movement from night normative worlds to occult practices interwoven with daytime activities. They also create subtle social rules governing actors and their practices.     

Ecological and genetic consequences of fragmentation in a semiarid Mediterranean urban forest

Urbanization threatens biodiversity worldwide and is expected to increase in the future. This involves intensification of fragmentation and increase of urban forest remnants. Thus, it is important to understand the functioning of these patches for the preservation of local biodiversity. Mutualistic interactions such as seed dispersal have a key role in the dynamics of plant populations and could help to mitigate the negative effects of fragmentation on wild plant populations. In this context, we have used the mastic Pistacia lentiscus, a common Mediterranean shrub, as a model to study the interaction between seed dispersal by birds and the local genetic diversity of individuals in a highly fragmented semiarid forestry area of the Iberian Southeast (Murcia, Spain). Results reveal a high genetic diversity and a lack of differentiation between shrub patches of P. lentiscus in the area, probably as a result of a strong, but rather recent fragmentation, and an apparently poor contribution of birds to the dispersal of Pistacia seeds. However, the existence of latent impacts cannot be discarded, since at least one of the patches shows some signs of inbreeding.     

The role of woodpeckers (family: Picidae) as ecosystem engineers in urban parks: a case study in the city of Madrid (Spain)

Urban Ecosystems - Many species of the family Picidae, such as the woodpeckers, excavate the tree-cavities where they nest. Frequently the cavities are used during a single breeding season and...     

Butterflies in the city: a review of urban diurnal Lepidoptera

Human migration to urban centers has resulted in diverse environmental disturbances that affect biodiversity. Although urbanization has been highlighted as one of the main drivers of biodiversity endangerment, this topic is still poorly studied in many countries. In order to establish the status quo of the ecology of butterflies in urban centers, we gathered publications focused on urban butterflies (Lepidoptera). We compiled a total of 173 studies from 37 countries and more than 110 urban areas, including published papers and theses (1956–2015). Most papers (69 %) addressed ecological topics, 14 % were focused on biological conservation, and 17 % corresponded to species lists. In summary, most studies revealed a negative impact of urbanization intensity on butterfly diversity (richness and abundance). In fact, we found studies reporting local extinctions due to urbanization, highlighting the causes related to them. The study of charismatic urban wildlife groups, such as butterflies, is a promising field, as there are still important gaps in our comprehension of the ecological patterns and processes that occur in urban areas. Undoubtedly, understanding the response of butterflies to urbanization will aid in the development of urban biodiversity management, planning, and conservation strategies worldwide, which together with knowledge of other wildlife groups and socioeconomic variables, will lead us to more sustainable, livable, and biodiverse cities.