Parasites in space and time: a case study of haemosporidian spatiotemporal prevalence in urban birds

Prevalence responses to anthropic factors differ across hosts and parasite species. We here analyzed the spatiotemporal variation of avian haemosporidian prevalence in bird assemblages of the Mooswald forest (i.e., urban greenspace; Freiburg, Germany), in response to local environmental features (e.g., water sources, human presence (visited)/absence (unvisited)) and bird-level traits (e.g., body condition, age, sex) in 2?years. We used a nested PCR protocol (mitochondrial (mt)DNA cytochrome b (cyt b) gene) and microscopy to determine haemosporidian infections. Prevalence was analyzed using a general linear multi-model (glmulti) approach with Akaike information criterion corrected for small samples (AICc), with subsequent model inferences using a GLMM on the best selected model, considering bird species as a random factor. Analyses were conducted for the main understory bird species (Blackcap – Sylvia atricapilla, Chaffinch – Coereba flaveola, Great Tit – Parus major, Blue Tit – Cyanistes caeruleus, European Robin – Erithacus rubecula, Blackbird – Turdus merula, Song Thrush – Turdus philomelos). We further conducted spatial autocorrelation analyses for all haemosporidian infections, and classification and regression trees (CARTs) for focal species. We analyzed a total of 544 samples of seven bird species. In 2011 prevalence for Haemoproteus/Plasmodium was 25.8% and 11.7% for Leucocytozoon. In 2013 prevalence for Haemoproteus/Plasmodium was 26.5% and 35.5% for Leucocytozoon. Haemosporidian prevalence was significantly different between some focal species. There was a negative association between distance to the nearest water source and prevalence in the year 2011, and the opposite pattern for the year 2013. However, when analyzed for the six focal species separately, such a relationship could change from a negative to a positive one, or there could be no relationship at all. For Leucocytozoon there was higher prevalence in the section of the forest visited by humans. We did not find spatial autocorrelation for prevalence across the study site, but there were statistically significant local spatial clusters in the visited section. Although there were similar responses of prevalence to some factors, infection patterns were generally bird species-specific. Thus, prevalence is a labile epidemiological parameter, varying spatiotemporally in an idiosyncratic way.     

Gifting as Governance: NGO Service Projects and Disciplinary Power in Rural Migrant Settlements in China

ABSTRACT

In contemporary China, migrant workers have gathered in urban villages and formed communities of their own. The regulative power of the state has not fully penetrated these enclaves, thus creating opportunities for NGOs to shoulder many of the ongoing welfare responsibilities. The primary goal of this study was to explore how NGO service projects can generate a new type of disciplinary power through give-and-take practices. I argue that service projects allow the givers to transform their economic power and social resources into political power, through which social inequality is obscured, legitimised, and translated into the delivery of ‘love’, ‘caring’ and ‘compassion’. Such political power also delivers middle-class values and lifestyles to rural migrants, who feel obligated to transform their subjectivities in order to reciprocate.     

Slimes in the city: The diversity of myxomycetes from inner-city and semi-urban parks in Sydney,Australia

Natural and agricultural areas are rapidly becoming urbanised, causing changes in habitat structure and diversity. Although the effect of urbanisation on the diversity of terrestrial plants and animals has been well studied, there is a significant gap in our understanding of how urbanisation impacts diversity in protists. Here, we measure the diversity of plasmodial slime moulds (a group of large, macroscopic protists also known as myxomycetes) in inner-city and semi-urban parks. We studied the impact of a range of environmental characteristics (pH, temperature, canopy cover, area of green space and substrate type) on species richness and composition of myxomycetes. We also examined the influence of different degrees of urban development surrounding these parks. Species composition was significantly different between substrate types but not between inner-city and semi-urban parks. Temperature was the only environmental characteristic that affected diversity, having a negative effect on myxomycete presence. Our findings suggest that myxomycete diversity in urban parks is driven by factors at the substrate level, and not by the park's location within the city (inner city or semi-urban).     

Parasites in the neighbourhood: Interactions of the mistletoe Phoradendron affine (Viscaceae) with its dispersers and hosts in urban areas of Brazil

Mistletoes constitute an important food resource for animals in many ecosystems. However, these plants are considered pests in urban areas because of deleterious effects they have on the host trees. Studies in urban areas were mostly focused on listing host species or procedures to control the “pest”. In this sense, broader studies including several aspects of mistletoes ecology in urban ecosystems are still missing. We studied the interaction of the mistletoe, Phoradendron affine, with its dispersers and hosts in two urban sites in Uberlândia, Brazil. Phoradendron affine fruits were consumed almost exclusively by Euphonia chlorotica, which was crucial for seed germination. Parasitism was recorded in five hosts, two native (Handroanthus chrysotrichus and Tabebuia roseoalba) and three exotic species (Spathodea campanulata, Ligustrum lucidum and Melia azedarach). Mistletoes were found parasitizing larger host trees, a trend commonly reported for mistletoe-host interaction. Mistletoe seed germination was not affected by the trees species, whether host or non-host, but the radicle of germinated seeds could not penetrate the bark and seedlings invariably died in non-host species. We found a high prevalence of parasitism in our study, in comparison to what previous studies reported for natural areas. The spatial distribution of the hosts and high light incidence on isolated host trees may lead to this high prevalence in urban areas. Rather than eradicated, mistletoes in urban areas should be ecologically managed and their importance for bird species conservation must be considered. More studies to determine which bird species are favoured by mistletoe presence in urban areas will be essential for this purpose.     

北京市门头沟区工业废弃地生态修复工程的关键技术

随着改善城市环境质量、加强城市生态建设工作的呼声日益提高,工业废弃地的生态修复和环境建设工程越来越受到重视。以北京市门头沟区永定镇大砂坑生态修复二期工程为例,提出了这类工程的技术关键,首先是进行科学的规划设计,二是稳定坡体,三是建立排水系统,四是土壤改良,五是充分发挥植物的生态效益。重点论述了植物选择和种植中的有关问题,并结合该项目在前期立项、勘察、设计、施工中出现的一些问题进行了探讨和总结。     

The effects of different urban land use patterns on soil microbial biomass nitrogen and enzyme activities in urban area of Beijing, China

Soil microbes are affected by various abiotic and biotic factors in urban ecosystem due to land use change. The effects of different land use patterns on soil microbial properties and soil quality are, however, largely unknown. This study compared soil nutrient status, microbial biomass nitrogen and enzyme activities under five different land use patterns—nature forest, park, farmland, street green, and roadside tree sites at various soil depths in Beijing, China. The results showed that soil properties were significantly affected by urban land use patterns and soil depths in the urban environment. Compared to forest sites, soil nutrients were markedly decreased in other land use patterns, except the highest soil organic matter content in roadside tree sites in 0–10 cm soil layer. Soil microbial biomass nitrogen showed the order as follows: nature forest > park > farmland > street green > roadside tree in 0–10 cm soil layer, and it decreased along with the soil depth gradient. Furthermore, urease activity was highest in nature forest and lowest in street green and roadside tree soils in each depth, while the activity of protease ranged between 0.84 and 3.94 mg g^?1 with the peak appeared in roadside tree at 30–40 cm soil layers. Nitrate reductase activity was also extremely higher in street green than other land use patterns. Correlation analyses suggested that change of soil microbial biomass and enzyme activity in different land use patterns were mainly controlled by nutrient availability and soil fertility in urban soils.     

海拔对儿童和青少年生长发育的影响

为进一步探讨自然环境因素对生长发育的影响,本文收集了14个省会城市1996年以来7-18岁107986(男56300,女51686)儿童青少年的身高、体重、胸围资料及体质测量当年的海拔、年降水量、年均气温和年日照时数资料,做海拔等自然环境因素与发育指标的Z-分数和发育分相关与回归分析。结果表明,从低海拔组到中海拔组、高海拔组,儿童青少年的生长发育指标逐步下降,其中体重与BMI有统计学意义(P0.05),低海拔组发育指标明显好于高海拔组;生长发育水平与海拔的相关系数大于年均气温和日照时数,与年降水量不相关;回归分析表明海拔每增加1000m,身高、体重、胸围和BMI分别减少0.112,0.101,0.043和0.118个Z-分数。在四项自然环境因素中,海拔对生长发育的影响最大,对身高、体重、胸围和BMI的贡献率分别是28.0%,26.8%,12.0%,16.8%。     

Effects of anthropogenic disturbances on the butterfly assemblage in an urban green area: the changes from 1990 to 2005 in Kanazawa Castle Park, Japan

Kanazawa Castle Park (KCP) is an isolated urban green area in Kanazawa, Japan. A mature forest had developed there since 1949, but it was partially deforested from 1996 to 1999. Moreover, most of the grasslands in KCP were removed from 2000 to 2002. In this study, we report the damage to the butterfly assemblage by these anthropogenic disturbances and subsequent recovery after the disturbances, using previous literature on the butterfly assemblage in KCP from 1990 to 1994 and our monitoring data from 1999 to 2005. In addition, to understand urbanization effects, we also compared the butterfly assemblage of KCP with that of Tawara, a satoyama area 6 km away from KCP. Before the urbanization around KCP, KCP might have had a butterfly assemblage similar to Tawara. The previous articles indicate that 33 species lived in KCP before the partial deforestation. The number of generalist species (multivoltine and polyphagous species) was similar in KCP and Tawara (22 vs. 19), but that of specialist species (uni-bivoltine and oligophagous species) was lower in KCP than in Tawara (5 vs. 15). Six species, composed of a bamboo grass feeder, mantle feeders, herb/grass feeders, and a multi-feeder, disappeared from KCP after the deforestation and have not yet recolonized. The grassland removal also affected herb/grass feeders negatively, but they have been recovering quickly following the partial grassland recovery. Some species that disappeared after the deforestation were sporadically found from 2000 to 2005 probably due to immigration from the surrounding rural areas (the nearest one is 2 km away). For recolonization of the lost species, recovery of the interior and edge of the forest, which are the habitats for these species, is necessary.     

Evaluation of floristic diversity in urban areas as a basis for habitat management

Questions: How can floristic diversity be evaluated in conser‐vation plans to identify sites of highest interest for biodiversity? What are the mechanisms influencing the distribution of species in human‐dominated environments? What are the best criteria to identify sites where active urban management is most likely to enhance floristic diversity? Location: The Hauts‐de‐Seine district bordering Paris, France. Methods: We described the floristic diversity in one of the most urbanized French districts through the inventory of ca. 1000 sites located in 23 habitats. We built a new index of floristic interest (IFI), integrating information on richness, indigeneity, typicality and rarity of species, to identify sites and habitats of highest interest for conservation. Finally, we explored the relationship between site IFI and land use patterns (LUP). Results: We observed a total of 626 vascular plant species. Habitats with highest IFI were typically situated in seminatural environments or environments with moderate human impact. We also showed that neighbouring (urban) structures had a significant influence on the floristic interest of sites: for example, the presence of collective dwellings around a site had a strong negative impact on IFI. Conclusions: Our approach can be used to optimize management in urban zones; we illustrate such possibilities by defining a ‘Site Potential Value’, which was then compared with the observed IFI, to identify areas (e.g. river banks) where better management could improve the district's biodiversity.     

Wood anatomy constrains stomatal responses to atmospheric vapor pressure deficit in irrigated, urban trees

Plant transpiration is strongly constrained by hydraulic architecture, which determines the critical threshold for cavitation. Because species vary greatly in vulnerability to cavitation, hydraulic limits to transpiration and stomatal conductance have not generally been incorporated into ecological and climate models. We measured sap flow, leaf transpiration, and vulnerability to cavitation of a variety of tree species in a well-irrigated but semi-arid urban environment in order to evaluate the generality of stomatal responses to high atmospheric vapor pressure deficit (D). We found evidence of broad patterns of stomatal responses to humidity based on systematic differences in vulnerability to cavitation. Ring-porous taxa consistently had vulnerable xylem and showed strong regulation of transpiration in response to D, while diffuse-porous taxa were less vulnerable and transpiration increased nearly linearly with D. These results correspond well to patterns in the distribution of the taxa, such as the prevalence of diffuse-porous species in riparian ecosystems, and also provide a means of representing maximum transpiration rates at varying D in broad categories of trees.