Adaptive parental feeding as a factor influencing the reproductive rate in the grey starling

1. Adaptive parental feeding of chicks is one of the factors influencing the reproductive rate of a local population.
2. The food resources in the rural and urban colonies in Tokyo were entirely different as proved by collar experiments of the chicks.
3. In the rural habitat the mole-cricket of fair size (1 g) and of a high nutritive value was the ‘key food' to all broods and only a few other items were added for larger broods.
4. In the urban habitat the food consisted of both animal and plant (fruits) items of various kinds, but the animal matter was mostly small and of poor nutritive value, and fruits are much less nutritive than animal matters as experimentally proved with captive chicks by using cherries which are the most abundant and favoured fruit.
5. Thus the food preference and the feeding ability of parents had more important effect upon growth rate and flying success of chicks in the urban colony than in the rural, especially in larger broods.
6. In the rural colony, the adaptive reaction of parents to a large brood size (experimentally increased) was evident in a pair which adequately switched the normal food, the secretive mole-cricket, to an easily obtainable kind, the small white pupae and caterpillars.
7. Such focussed or concentrated foraging was also shown to some other food items to be found in clustered condition and selection for large size was also suggested, since such large foods as the gecko or lizard were brought though they were disgorged by chicks in some cases.
8. Subject to various factors, there is the maximum possible feeding frequency for the parents and therefore, however hard the parents might work, there were limits of brood size they could successfully raise.
9. Such limits were 6 chicks for some parents or 7 for others, and a single parent could raise not more than 3 chicks.
10. Thus in the grey starling the broods of 5–6 chicks are of the most efficient size in reproductive rate and are most common, though are subject to difference of local food situation.

     

A study on the characteristics of urban ecosystems and plans for the environment and ecosystem in Gangnam-gu,Seoul, Korea

The aim of this study is to establish a plan for the environment and ecosystem by studying the characteristics of urban ecosystems, involving one of Seouls districts for environment-friendly urban management. Biotope type in Gangnam-gu was classified into six large groups: forest, planted area, grassland, stream and wetland, cultivated land and urbanization area. Then the six groups were again divided into 22 small groups on the basis of composition of species, naturalness, diversity of stratification and scarcity. Filicales and Disporum smilacinum communities, moisture-loving native plants which are well worth conserving, were distributed widely throughout the northern slope of Mt. Daemosan, an outer mountain in Gangnam-gu. In contrast, Ageratina altissima, one of the naturalized plants in Seoul, was found to spread over Mt. Maebongsan and the Cheongdam neighborhood park, residual mountain-type parks located along the northern part of the Yangjaecheon stream. The southern part of the stream was found to be used as a route for woodpeckers and small wild birds, since the districts residual mountain type park was connected to large outer forest whose naturalness was in good condition. Under the plan for ecosystem conservation and restoration, conservation and restoration areas with highly valuable conservation biotopes were selected. Under the plan for ecosystem networking, a natural corridor and a green corridor were designed to connect greenspaces for the migration of woodpeckers. The plan for enlarging the greenspaces has a short-, mid- and long-term plan for areas that are need to secured greenspaces. The plan was set after comparing greenspaces in each block within the district.     

Natural controls and human impacts on stream nutrient concentrations in a deforested region of the Brazilian Amazon basin

This study documents regional patterns in stream nitrogen and phosphorus concentrations in the Brazilian state of Rondônia in the southwestern Amazon basin, and interprets the patterns as functions of watershed soil properties, deforestation extent, and urban population density. The survey includes 77 different locations sampled in the dry and wet seasons, with a watershed size range from 1.8 to 33,000km² over a total area of approximately 140,000km². A sequential regression technique is used to separate the effects of natural watersheds properties and anthropogenic disturbance on nutrients and chloride. Natural variation in soil texture explains most of the variance in stream nitrate concentrations, while deforestation extent and urban population density explain most of the variance in stream chloride (Cl) and total dissolved nitrogen (TDN) concentrations. Stream TDN, total dissolved phosphorus (TDP), particulate phosphorus (PP) and Cl concentrations all increase non-linearly with deforestation extent in the dry season after controlling for natural variability due to soil type. Stream nutrient and Cl disturbances are observed only in watersheds more than 66–75% deforested (watershed area range 2–300km²), suggesting stream nutrient concentrations are resistant to perturbation from vegetation conversion below a 66–75% threshold. In heavily deforested watersheds, stream Cl shows the largest changes in concentration (12±6 times forested background), followed by TDP (2.3±1.5), PP (1.9±0.8) and TDN (1.7±0.5). Wet season signals in Cl and TDP are diluted relative to the dry season, and no land use signal is observed in wet season TDN, PN, or PP. Stream TDN and TDP concentrations in non-urban watersheds both correlate with stream Cl, suggesting that sources other than vegetation and soil organic matter contribute to enhanced nutrient concentrations. Small, urbanized watersheds (5–20km²) have up to 40 times the chloride and 10 times the TDN concentrations of forested catchments in the dry season. Several large watersheds (1000–3000km²) with urban populations show higher Cl, TDN and TDP levels than any small pasture watershed, suggesting that human impacts on nutrient concentrations in large river systems may be dominated by urban areas. Anthropogenic disturbance of dry-season stream Cl and TDN is detectable in large streams draining deforested and urbanized watersheds up to 33,000km². We conclude that regional deforestation and urbanization result in changes in stream Cl, N and P concentrations at wide range of scales, from small pasture streams to large river systems.     

文化景观视角下的历史性城市景观

历史性城市景观是遗产保护领域近十几年来提出的新概念,关于其学术意义的讨论也层出不穷。从文化景观所蕴含的时空过程的学术视角着眼,分别梳理了文化景观的学术脉络与遗产领域中的文化景观和历史性城市景观的实践发展历程,指出历史性城市景观并没有超出文化景观的学术范畴,而遗产领域当前面临的很多问题都与对文化景观学术内涵的认知缺陷有关。只有充分借鉴和吸收文化景观的学术成果,才能真正有效地应对世界遗产实践过程中复杂变化的人地关系等挑战。     

Blood-meal preferences and avian malaria detection in mosquitoes (Diptera: Culicidae) captured at different land use types within a neotropical montane cloud forest matrix

Human activities modify environmental conditions, altering ecological interactions that can contribute to the increasing number of vector-borne pathogens affecting both human and wildlife populations. There is a dearth of knowledge about mosquitoes feeding preferences and their role as potential vectors of haemosporidian parasites, particularly in modified habitats. During 2013–2014 we sampled mosquitoes in five different land use types within a cloud forest matrix. From a total of 4107 adult mosquitoes, 90 were engorged. We extracted DNA from mosquito blood-meals, abdomens, and thoraxes, which belonged to seven different species. Seventeen specimens were positive for avian Plasmodium parasites. We were able to identify the blood-meal source of 10 mosquitoes, the identified vertebrate species were: Homo sapiens (Human), Sturnira hondurensis (Bat), and Bos taurus (Cow). Our results show that Culex restuans is positive for avian malaria and it is feeding on both humans and domestic animals at urban and peri-urban habitat types, where it is also an abundant species throughout the year. Furthermore, Aedes quadrivittatus, also positive for avian malaria, is feeding on humans in the well-preserved cloud forest, where this mosquito species is highly abundant. This study is the first in Mexico to provide reference data showing generalist mosquito feeding preferences and presence of avian Plasmodium at locations with different land use types.     

Benzo(a)pyrene diolepoxide-haemoglobin and albumin adducts at low levels of benzo(a)pyrene exposure

A biomonitoring study was conducted to simultaneously measure individual benzo(a)pyrene (BaP) exposure in 50 office employees, not occupationally exposed to polycyclic aromatic hydrocarbons (PAH), using personal samplers and the formation of (+) r-7, t-8-dihyroxy-t-9,t-10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) adducts to haemoglobin (BPDE–Hb) and serum albumin (BPDE–SA). The population enrolled was exposed to an average of 0.58 ± 0.46 ng BaP m^?3 (mean ± SD). The concentration of BaP collected from smokers' samples was double that from non-smokers (P = 0.007). BPDE adducts to Hb and SA were quantified as BaP tetrols released from hydrolysis of macromolecules and measured by high-resolution gas chromatography–negative ion chemical ionization–mass spectrometry. BPDE–Hb adducts were detected in 16% of the population and BPDE–SA adducts in 28%. Smoking did not affect adduct formation. When BaP personal monitoring data were used as the criterion of exposure, no correlation was found with the presence and the levels of BPDE–Hb and BPDE–SA adducts. Undetected sources of PAH, such as the diet, might markedly alter the exposure profile depicted by individual air sampling and affect the frequency and levels of protein biomarkers. This is the first comparative analysis of BPDE–Hb and BPDE–SA adducts, providing reference values for these biomarkers in a general urban population. However it is difficult to establish which biomarkers would be the more relevant in assessing low BaP exposure, due to undetectable factors such as dietary PAHs, that might have influenced the results to some degree.     

Indicators for contaminant transport in wetlands

Wetlands provide significant ecological services for urban regions in terms of water supply, wastewater treatment, flood storage, drought resistance, etc. For wetland flows, it is crucial to understand the process of contaminant transport as it provides scientific support for applications associated with various urban services. Two indicators respectively as the critical length and duration are frequently adopted for risk assessment of incidental release of toxic or contaminant cloud. This paper presents a review on recent progresses in the analytical study of contaminant transport in wetland flows by Taylor dispersion at the phase-average scale. The method of concentration moments is introduced. Analytical procedures for determining the key quantity of Taylor dispersivity are given for typical wetlands with free water surface, respectively as the steady flow wetlands, tidal flow wetlands, and the two-layer flow wetlands. As an example of applications, critical length and duration of the contaminant cloud in the steady flow wetlands are analyzed based on the obtained Taylor dispersivity. Results show that in contrast to the temporary, localized influence of COD on water quality, the heavy metal Pb can give rise to more severe damage.     

Urban greenspace composition and landscape context influence natural enemy community composition and function

Conservation research has historically been aimed at preserving high value natural habitats, but urbanization and its associated impacts have prompted broader mandates that include the preservation and promotion of biodiversity in cities. Current efforts within urban landscapes aim to support biodiversity and diverse ecosystem services such as storm water management, sustainable food production, and toxin remediation. Arthropod natural enemies provide biocontrol services important for the ecosystem management of urban greenspaces. Establishing habitat for these and other beneficial arthropods is a growing area of urban conservation. Habitat design, resource inputs, management, and abiotic conditions shape the value of greenspace habitats for arthropods. In general, larger patches with diverse plant communities support a greater abundance and diversity of natural enemies and biocontrol services, yet opposing patterns or no effects have also been documented. The surrounding landscape is likely a contributor to this variation in natural enemy response to patch-scale habitat design and management. Looking across rural–urban landscape gradients, natural enemy communities shift toward dominance by habitat generalists and disturbance tolerant species in urban areas compared to rural or natural communities. These changes have been linked to variation in habitat fragmentation, plant productivity and management intensity. In landscape-scale studies focusing solely within cities, variables such as impervious surface area and greenspace connectivity affect the community assembly of natural enemies within a patch. Given these findings, a greater mechanistic understanding of how both the composition and spatial context of urban greenspaces influence natural enemy biodiversity–biocontrol relationships is needed to advance conservation planning and implementation.     

Archaeobotany of the Old Prague Town defence system, Czech Republic: archaeology, macro-remains, pollen, and diatoms

The stone fortification of Prague Old Town was constructed shortly after A.D. 1230. Large-scale archaeological and archaeobotanical research has been carried out in this area in recent years. The deep moat and the drainage ditch have been excavated at several places in front of a line of former ramparts. During the initial period of their existence, the moat and the ditch contained only minimal waste. A sudden change in the management of these features occurred at the beginning of the 14th cent., when they started to be filled with large amounts of rubbish. This article concentrates on the evaluation of these rubbish strata at three profiles through the drainage ditch and one profile through the dry moat. The results of plant macro-remains (including wood), pollen, and diatom analyses clearly demonstrate the development of the local (aquatic) environment from being relatively clean to highly polluted. An actualistic (phytosociological) approach was adopted to reconstruct the local environment of the town periphery in detail, and to distinguish a variety of habitats that were situated in the economic hinterland of the city. Some species from the rich assemblages of plant remains are interpreted in terms of their use in High Medieval households. Diatom analysis completes the picture by providing the proxy data on water quality history in the drainage ditch. Received September 15, 2001 / Accepted May 21, 2002