Suburban Ecosystems Research Articles

An on-campus, collaborative restoration of landfill and degraded suburban ecosystems

An on-campus, collaborative restoration of landfill and degraded suburban ecosystems

Ecological and Faunistic Analysis of Lumbricidae Species Composition of Natural Biogeocenoses and Man-made Territories

Earthworms make up the bulk of the soil mesofauna and play an important role in the transformation of organic matter, the formation of the pedosphere, the regulation of the flows of matter, energy and information in ecosystems. In this research, we have studied the species composition of earthworms in urban and suburban ecosystems of the foothills of the Trans Ili-Alatau. As a result of the work, 11 species of the Lumbricidae family of the Oligochaeta class were discovered. 6 species out of them have been discovered in our Republic: Aporrectodea rosea, Lumbricus rubellus, Lumbricus castaneus, Octolasion lacteum, Dendrobaena octaedra and Aporrectodea caliginosa are widespread. The genus Lumbricus is the most common in terms of the number of individuals in the studied territories. Significant differences have been established in the species composition of earthworms in technogenic and natural biogeocenoses. The lumbricides are the absolute dominants in two ecosystems. Along with the species composition of earthworms, seasonal dynamics were also studied, it was found that their maximum activity is observed at the most favorable ratio of temperature and humidity.

To the Issue of Solid Municipal Waste in the Irkutsk Region

The article presents data on solid municipal waste (SMW) in the Irkutsk region as the main source of pollution of urban and suburban ecosystems. SMW is currently the most massive and dangerous type of waste, which can lead to irreversible consequences. In Russia, very active attention is being paid to the issues of waste collection and recycling in recent years. The objectives, which the authors set themselves, are a detailed analysis of the situation of SMW in the Irkutsk region. Special attention is focused on the location of already existing facilities as well as planned until 2027 ones. Unfortunately, the population of the Irkutsk region is not yet ready for mass separation of garbage according to its origin and recyclability, but a number of measures are proposed to change the situation. Statistical, comparative-geographical, cartographical and the method of comparative analysis and synthesis were used. The paper presents an analysis of the work of regional operators in accordance with the federal project Integrated system of SMW management carried out for the first time. The amount of waste taken to landfills in the Irkutsk region should be reduced by half by 2030 while sorted waste should gain 100 per cent of all garbage thrown away. The study results in the following conclusions: the region is not ready for processing and recycling of certain categories of waste such as glass or galvanic elements. There are simply no recycling facilities for a number of wastes, which leads to uncontrolled emissions and disturbance of the environment (soil, water, and atmospheric air) but the Government of Russia and the Irkutsk Region authorities are actively reforming the system of SMW management.

Specific alien plant species predominantly deliver nectar sugar and pollen but are not preferentially visited by wild pollinating insects in suburban riparian ecosystems.

The invasion of alien plants has been rapidly proceeding worldwide due to urbanisation. This might be beneficial to wild pollinating insects, since some alien plant species have large flowers and/or long flowering periods, which can increase nectar sugar and pollen availability. To determine the relative contribution of alien plants to floral resource supply and whether resource-rich alien plants, if any, serve as an important food source of pollinating insects, we performed year-round field observations in suburban riverbanks. We quantified the per-unit-area availability of nectar sugar and pollen delivered by alien and native flowering species and counted wild flower visitors (bees and wasps, hoverflies and butterflies) per plant species. The available nectar sugar and pollen per area were predominantly delivered by a few specific alien species, and the relative contribution of other species to floral resource provision was low throughout the period that wild flower visitors were observed. Nonetheless, the resource-rich alien plants were not visited by as many insects as expected based on their contribution to resource provision. Rather, on a yearly basis, these plants received equal or even fewer visits than other flowering species, including resource-poor natives. We show that despite their great contribution to the gross floral resource supply, resource-rich alien plants do not serve as a principal food source for wild pollinating insects, and other plants, especially natives, are still needed to satisfy insect demand. For the conservation of pollinating insects in suburban ecosystems, maintaining floral resource diversity would be more beneficial than having an increase in gross floral resources by allowing the dominance of specific alien plants.

06. Diet of the recently introduced white-lipped frog Leptodactylus fragilis from a suburban ecosystem in western Cuba

ABSTRACT - Diet and trophic interactions are essential for understanding aspects of the natural history of a species and evaluating its role within the ecosystem. A successful coloniser often has the ability to exploit a wide variety of prey during its establishment and may generate negative impacts due to competition with the local fauna. During both the dry and rainy seasons of 2019, in a suburban ecosystem in western Cuba, we analysed the diet of the recently introduced white-lipped frog Leptodactylus fragilis. Captured frogs were measured and stomach-flushed and released 24 h after analysis at the site of capture. Ninety-one L. fragilis were captured, 73 of them (80.2 %) had prey in the stomach. The most consumed prey were beetles, followed by spiders, and crickets. No difference was observed in prey consumption between seasons. This frog may change its foraging strategy according to the habitat it occupies. In this study, we observed high values of food niche breadth, which may imply a greater competition of L. fragilis for food resources with the native syntopic anurans in Cuba. Studies on temporal and spatial dynamics are needed to understand the possible competitive interaction with native amphibians in this area.

The effects of red fox scent on winter activity patterns of suburban wildlife: evaluating predator-prey interactions and the importance of groundhog burrows in promoting biodiversity

During winter, prey species in suburban areas of the northeastern United States must consider trade-offs in maximizing survival while they are simultaneously constrained by predators and climatic conditions associated with winter such as snow and low temperatures. Many mammalian prey mitigate the physiological stress from the cold by taking refuge in burrows. Some have also developed olfactory sensitivity to predator scent cues as they attempt to avoid predation in the landscape of fear and co-evolutionary arms race between predators and prey. The Eastern cottontail (Sylvilagus floridanus) is one of these species that both uses burrows in winter and is sensitive to scents. However, despite the importance of cottontails in the diet of Red foxes (Vulpes vulpes), one of their major predators, little is known about scent cues that cottontails use to detect foxes. Eastern cottontails and other suburban wildlife that occupied burrows dug by Groundhogs near Ithaca, New York, USA were exposed to scent wicks treated with Red fox urine during the winter of 2017–2018 to determine if the frequency of burrow use would decrease because of a perceived heightened risk of predation. We observed no response to the predator odor by cottontails and the other burrow-utilizing species. This lack of a behavioral response by prey may be due to the attenuation of fear in suburban environments. A surprising variety of mammalian and avian taxa (n = 22) were recorded at burrows, including Striped skunks, mice, Domestic cats, Virginia opossums, Bobcats, White-tailed deer, Weasels, a Coyote, and a Gray fox. Surprisingly we did not observe a single Red fox, for whom intraspecific scent cues are also important. We also documented daily patterns of activity around burrows of the five most commonly observed taxa. Our investigation reveals that Groundhogs are notable ecosystem engineers whose burrows function as important landscape features and local hotspots of biodiversity during the winter in a suburban ecosystem.

Trading fear for food in the Anthropocene: How ungulates cope with human disturbance in a multi-use, suburban ecosystem

Resource distribution, predation risk and disturbance in space and time can affect how animals use their environment. To date few studies have assessed the spatiotemporal trade-off between resource acquisition and avoidance of risks and human disturbance in small protected areas embedded in an urban matrix. A better understanding of the forage-safety trade-off in urban protected areas (UPA) is key to the design of evidence-based approaches to deal with the ever-increasing human-wildlife impacts typical of UPA. Herein, we analyzed camera trap data to evaluate how two ungulate species trade fear for food in a 60 km2 human-dominated UPA without natural predators. We found that wild boar (Sus scrofa) were predominantly active at night, while roe deer (Capreolus capreolus) showed a typical bimodal crepuscular activity pattern. Occupancy analysis indicated that deciduous forest and the presence of high seats for hunting played an important role in determining the space use of wild boar. For roe deer, we found indications that the presence of forest influenced space use, although the null model was retained among the top ranked models. Our results confirm that wild boar and roe deer are able to thrive in heavily human dominated landscapes characterized by intensive recreational use and hunting, such as protected areas embedded in an urban matrix.

Factors of soil and atmospheric air degradation and their influence on the state of plants in urban and suburban ecosystems

This paper presents data on characteristics and extent of degradation of soil quality, atmospheric air and plants in urban and suburban areas of the Lower and Middle Volga region, Central Chernozem region. The goal of the research is to analyze and present data of environmental monitoring of soil, atmosphere and plants. On the example of the Saratov, Voronezh and Penza Regions, the values of the state of terrestrial ecosystems on different types of soils are established. The predominant position in terms of area and economic use is occupied by soils transformed in the course of urban development, as well as artificial soils. Compaction, anthropogenic inclusions, littering and heavy metal contamination are of great importance in the degradation of the soil cover. In the air-technogenic pollution, the formation and deposition of dust on the leaf surface of plants plays a significant role. Bioindicative signs in the analysis of the state of the environment and ecological systems were indicators of the viability, condition and stability of trees and shrubs. They are obtained based on average data from the research and subsequent assessment of life status. Separately, the indicators of degradation of woody plants assimilation organs depending on the levels of unfavorable soil-ecological and aerogenic conditions in urban and suburban ecosystems of the studied regions are considered. The significance of degradation of environmental objects by analyzed anthropotechnogenic factors is reflected in the correlation analysis results.

Environmental assessment of health indicators of woody plants in natural and man-made conditions

The indicators of the sanitary condition of woody plants in the conditions of natural and artificial ecosystems of the Voronezh and Saratov Regions were established and analyzed. In suburban ecosystems of the research area, the state of woody plants is determined at the level of weak damage. In suburban areas of Balashov with the greatest economic and technosphere potential, woody plants reach an average (moderate) degree of damage. In remote relatively preserved ecosystems (control parameters), the state of these organisms corresponds to a weak ecological diagnostic criterion. According to the identified average arithmetic sanitary indicators in the Voronezh Region, the best condition is characterized by woody plants in the ecosystems of Novohopersk and Gribanovsky, in the Saratov Region - in Turki and Samoylovka. There were also significant differences in the arithmetic mean parameters of the sanitary condition of this group plants representatives differentiated by functional zones. The highest damage values are typical for woody plants in the urban ecosystems of industrial zones. The maximum danger to woody plants was observed within these zones in Povorino, Borisoglebsk, and Balashov with high-level average values of damage to these organisms. Significant concern is also caused by the defeat of the analyzed group of organisms in these cities as part of the ecosystems of the settlement zones. The results of the assessment of the sanitary condition of woody plants should be used as a scientific basis for landscaping, environmental protection and reforestation. Measures are proposed to improve the condition of woody plants in various types of ecosystems in the research area. According to the sanitary state of these organisms, it is possible to determine the limits of sustainability of ecological frameworks and differentiate the parameters of environmental comfort for the local population in different territorial categories.

An ecological analysis of the composition and condition of woody plants in urban and suburban ecosystems of the Khopyor River Region

The aim: to perform research of the species composition and condition of urban and suburban ecosystems of the Khopyor River Region. The route method was used for the species composition of woody plants. Also, using this method the conditions of the growth of trees and shrubs were described. The data of field ecological observations and researches were analyzed in the laboratory conditions. Plant species were identified by means of determinants. The geographical analysis and floristic belonging of plants in towns and villages is carried out. A diagnostics of the vital state of woody plants is carried out according to the complex of their external signs on ecologically different territories. It is found that the greatest species diversity is characterized by the family Rosaceae Juss. The poverty of the species composition of woody plants in the towns and villages of the research area is associated with insufficient introduction. The largest number of species of trees and shrubs in urban areas are characterized by parks and squares. Of great concern is the weakening of the vital condition of woody plants in the area of suburban highways. The greatest values of damages of the objects of the research are revealed at wood plants as part of roadside territories of towns and villages. The expediency to restore greening in ecologically problematic urban areas is obvious.

Loss of urban forest canopy and the effects on neighborhood soundscapes

The urban landscape constitutes a key aspect of human - nature interactions, as more than 60% of the world’s population resides in cities and their suburbs. This study focuses on the characteristics of the landscape that humans (and other organisms) perceive as sound and the role of a suburban soundscape in defining experience of place. Vegetation plays an important role in shaping soundscapes, both by creating sound and attenuating sound from natural and human sources. An invasive insect pest, the Emerald Ash Borer (Agrilus planipennis), is killing millions of ash trees (genus Fraxinus) throughout North America. As a result, many municipalities are systematically removing Fraxinus trees. The objective of this research was to determine if and how removal of a substantial amount of the urban forest in such a community causes changes in the local soundscape, particularly in the proportion of human-sourced sounds versus sounds associated with nature. We selected Arlington Heights, Illinois, as the study site, where a series of before-and-after sound recordings were gathered as ash trees were removed between 2013 and 2015. Comparison of recordings using the Raven sound analysis program revealed significant differences in some measures of sound attributes tested as tree canopy decreased. We detected more human-produced mechanical sounds (anthrophony) and fewer sounds associated with weather (geophony) in these sites. Changes in sounds associated with animals (biophony) varied seasonally. We conclude that monitoring changes in the proportions of anthrophony, biophony and geophony provides insight into fauna biodiversity and the human experience of a suburban ecosystem.

Non-native plants are a seasonal pollen source for native honeybees in suburban ecosystems

In urban and suburban ecosystems, biodiversity can depend on various non-native plant species, including crop plants, garden plants and weeds. Non-native plants may help to maintain biodiversity by providing a source of forage for pollinators in these ecosystems. However, the contribution of plants in urban and agricultural areas to ecosystem services has often been underestimated in biodiversity assessments. In this study, we investigated the pollen sources of native honeybees (Apis cerana) in an arboretum containing native trees and urban and agricultural plants in a suburban landscape. We surveyed the flowering tree species planted inside the arboretum, which were potential pollen sources. The number of potential pollen-source species of native trees peaked in June and July and decreased after August. We collected A. cerana pollen balls every month and identified plant species of pollen in the collected pollen balls using DNA barcoding. In total, we identified 29 plant species from A. cerana pollen balls. The probability of A. cerana using pollen from urban and agricultural plants was higher in July and August than in June. A. cerana collected pollen forages from native tree species (53%), but also gathered pollen from crop plants (13%), garden trees (19%) and native and non-native weeds (14%); the predominant pollen sources in September and October were the garden tree Ulmus parvifolia and the non-native weed Solidago altissima. We found that native honeybees used plants from a variety of habitats including non-native plants to compensate for apparent seasonal shortages of native tree sources in suburban ecosystems. Our results highlight the importance of assessments of both positive and negative roles of non-native plants in urbanized ecosystems to improve biodiversity conservation.

Spatial-temporal variation of ecosystem water use efficiency in Beijing’s suburban region

Suburban ecosystem has multiple functions such as soil conservation and water regulation, which are critical for the welfare of human beings in the city. Water use efficiency (WUE) is an important indicator of ecosystem function that represents the amount of productivity per unit mass of evapotranspiration (ET). Improving WUE of suburban ecosystem is significant to climate regulation by carbon sequestration and water consumption, especially for cities with severe water shortage like Beijing, the capital of China. Based on remote sensing data, this paper examined the spatial and temporal variations in WUE in Beijing’s suburban region from 2002 to 2010. The results showed that the average annual WUE was 0.868 g C mm-1 m-2. It has large spatial variation with the minimum of 0.500 g C mm-1 m-2 in the Miyun District. During the study periods, the area with significant increasing trend of WUE was 63.2% of the total suburban region. In terms of ecosystem type, the value of WUE was following the sequence, deciduous coniferous forest (0.921g C mm-1 m-2) > mixed forest (0.887g C mm-1 m-2) > deciduous broadleaf forest (0.884 g C mm-1 m-2) > shrubland (0.860 g C mm-1 m-2) > evergreen coniferous forest (0.836 g C mm-1 m-2) > grassland (0.830 g C mm-1 m-2). As ET was similar among the ecosystems, the difference in WUE was mainly due to the discrepancy of NPP. We found that NPP significantly correlated with the diversity of ecosystem type (represented by Shannon-Wiener index). Our results suggest that ecological engineering construction, scientific ecosystem type selection, ecosystem diversity improvement and drought-resistant species cultivation are conductive to improve ecosystem WUE in Beijing’s suburban region.

Citizen Science as a Tool for Augmenting Museum Collection Data from Urban Areas

Museum collections are critical to contemporary biological research, but museum acquisitions have declined in recent decades, hampering researchers’ ability to use collections to assess species responses to habitat modification, urbanization, and global climate change. Citizen science may be a key method to bolster museum collections data, particularly from urban regions, where ongoing data collection is critical to our understanding of ecosystem dynamics in a highly modified and variable landscape. In this study, we compare data collected as part of the citizen science project Reptiles and Amphibians of Southern California (RASCals), hosted on the platform iNaturalist (www.inaturalist.org), to data in the VertNet database (www.vertnet.org), which houses millions of museum collection records from over 250 natural-history collections, for four focal species, including a native lizard of conservation concern that has declined with urbanization, a native lizard that is widespread in urban areas, and two invasive aquatic species. We compared numbers of VertNet records over time to modern RASCals records, and the number of records collected from urban, suburban, and protected areas from both databases. For all species, citizen science records were generated much more rapidly than museum records. For three of our four focal species, RASCals participants over 27 months documented from 70% to 750% more records than were added to the VertNet database after 1990. For the urban-tolerant southern alligator lizard, RASCals participants collected nearly 45 times more modern urban records than are contained in the VertNet database. For all other species, the majority of RASCals records were collected within suburban or other highly modified landscapes, demonstrating the value of citizen science for collecting data within urban and suburban ecosystems. As new museum acquisitions decline, citizen science projects like RASCals may become critical to the maintenance of modern species distribution data.

System Approach in Environmental Risk Assessment of Suburban Ecosystems on the Sochi Coast

System Approach in Environmental Risk Assessment of Suburban Ecosystems on the Sochi Coast

Heavy Metals in Suburban Ecosystems of Industrial Centres and Ways of their Reduction

Abstract Technogenic contamination of ecosystems is one of the main dangers of our time. In order to reduce the harmful effects of this contamination and to provide cost-effective and environmentally safe food production methods, we are forced to look for ways of reliable analysis of the environmental situation, the selection systems of animal husbandry and regulations for the degree of impact of pollutants on the elements of the agroecosystem. This article presents the results of studies aimed at assessing the plight of the environment of a large industrial centre, and its anthropogenic impacts on every element of the suburban ecosystems. It presents data on maintenance and migration of anthropogenous pollutants in the trophic chains of pasturable ecosystems of the suburb of Volgograd. The authors have listed the industrial enterprises as the key sources of pollution. The features of the distribution of xenobiotics in the tissues and organs of calves and heifers of different breeds were analysed in the study. Conclusions were drawn on the accumulation of heavy metals and arsenic in cattle, and the impact of this factor on the quality of production. A comparative assessment of the resistance of different breeds of cows to the action of toxicants in the environment of the Lower Volga region was carried out. Ways to decrease the impact of pollutants on the cattle organism have also been suggested. The article pays attention to the environmental pollution of the industrial centre, the influence of these processes on all elements of an ecosystem including humans, and offers ways to minimize the damage.

Do coyotes Canis latrans influence occupancy of prey in suburban forest fragments?

With the extirpation of apex predators from many North American systems, coyotes Canis latrans have become the de facto top predator and are ubiquitous members of most ecosystems. Keystone predators aid in maintaining ecosystem function by regulating the mammal community through direct predation and instilling the landscape of fear, yet the value of coyotes regulating systems to this capacity is understudied and likely variable across environments. Since coyotes are common in the Midwestern United States, we utilized camera traps and occupancy analyses to assess their role in regulating the distribution of mammalian herbivores in a fragmented suburban ecosystem. Forest cover was a strong positive predictor of white-tailed deer Odocoileus virginianus detection, while coyote occurrence had a negative effect. Coyotes exerted a negative effect on squirrel (Sciurus spp.) and eastern cottontail rabbit Sylvilagus floridanus occurrence, while urban cover was a positive predictor for the prey species’ occurrence. These results suggest all 3 species behaviorally avoid coyotes whereby deer seek denser forest cover and squirrels and cottontails mitigate risk by increasing use of urban areas. Although previous studies reveal limited influence of coyote on the rest of the carnivore guild in suburban systems, we suggest coyotes play an important role in regulating the herbivorous mammals and hence may provide similar ecological benefits in urban/suburban forest fragments through trophic cascades. Furthermore, since hunting may not be allowed in urban and suburban habitats, coyotes might also serve as the primary regulator of nuisance species occurring at high abundance such as white-tailed deer and squirrels.

城乡交错带土壤氮素空间分布及其影响因素

PDF HTML阅读 XML下载 导出引用 引用提醒 城乡交错带土壤氮素空间分布及其影响因素 DOI: 10.5846/stxb201410081969 作者: 作者单位: 四川农业大学资源环境学院,四川农业大学资源环境学院,四川农业大学资源环境学院,四川农业大学资源环境学院,四川农业大学资源环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家"十二五"科技支撑计划项目(2012BAD14B18-2) Spatial distribution of soil nitrogen in an urban-rural fringe and its influencing factors Author: Affiliation: College of Resource and Environment of Sichuan Agricultural University,College of Resource and Environment of Sichuan Agricultural University,College of Resource and Environment of Sichuan Agricultural University,College of Resource and Environment of Sichuan Agricultural University,College of Resource and Environment of Sichuan Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城乡交错带土壤氮素是城乡生态系统中最重要的氮源与氮汇,但是城市化下的土壤氮素分布及其影响机制还不清楚,基于3S平台研究了土壤氮素在成都西郊城乡交错带的空间分布特征及城市化对土壤氮素的影响。结果表明,研究区内土壤全氮(STN)、硝态氮(NO3--N)和铵态氮(NH4+-N)含量均值分别为(1.46±0.06) g/kg、(50.04±3.59) mg/kg和(6.72±0.53) mg/kg。区内土壤氮素含量从近郊向远郊逐渐增高,STN和NO3--N含量为中部高于南北部,NH4+-N含量则由西北部和东南部向中部递增。方差分析表明,区内不同土地利用方式下STN、NO3--N和NH4+-N含量差异显著(P < 0.05)。回归分析显示STN含量与建筑密度(BD)、道路密度(RD)均呈现显著线性负相关(P < 0.05),NO3--N含量与道路密度呈极显著线性负相关(P=0.001),与建筑密度关系不明显(P=0.217)。土壤NH4+-N与建筑密度呈显著负线性相关(P=0.001),与道路密度呈显著指数相关关系(P=0.021)。研究结果显示城市发展使得城乡交错带土壤氮素含量降低,这种影响伴随着建筑面积的增加,道路长度的增加而加强。 Abstract:Urban-rural fringe is a special zone that evolved from the suburbanization accompanying intensified land use changes from agricultural to non-agricultural land. Nitrogen in the soil of urban-rural fringe is an important nitrogen source and sink for urban and suburban ecosystems. The nitrogen content changes not only affect greenhouse gas emissions, but also threaten plant nitrogen supply and water ecosystems. However, in suburb urbanization, the proportion of non-agricultural land, construction land, and road land exhibited a successive increase. Currently, the mechanism of spatial distribution of soil nitrogen, caused by an increase in non-agricultural land, remains unclear. In the present study, the 3S platform was used to investigate the spatial distribution of soil nitrogen and its influencing factors in the urban-rural fringe of the western suburbs of Chengdu. Results showed that the average contents of soil total nitrogen (STN), nitrate (NO3--N), and ammonium (NH4+-N) were (1.46±0.06) g/kg, (50.04±3.59) and (6.72±0.53) mg/kg, respectively. In the investigated region, average content of soil nitrogen gradually increased from the inner to the outer suburbs. The STN and NO3--N distribution in the inner suburbs were higher than those of the northern and southern areas. High STN(>1.5 g/kg) and soil NO3--N(> 62.2 mg/kg) values presented mass distribution in the eastern suburbs. In addition, NH4+-N in soil gradually increased from the northwest or southeast to the center, and the high values(> 8.5 mg/kg) presented irregular piece distribution in the eastern suburbs. Analysis of variance (ANOVA) showed that the difference of STN, NO3-N, and NH4+-N contents were significant under different land use patterns (P < 0.01). The STN content in vegetable fields was the highest (> 1.8 g/kg), followed by rape fields, gardens, and woodland (1.5-1.8 g/kg). Garlic fields and idle land were relatively moderate (1.0-1.5 g/kg), and residential land and urban green land were relatively low (< 1.0 g/kg). NO3--N content was ranked as residential land > vegetable field > garlic field > garden > rape field > idle field > woodland > urban green land. NH4+-N content was ranked as vegetable field > woodland > garden > rape field > garlic field > residential land > idle field > urban green land. Correlation analysis indicated that average STN content and building density (BD) showed a negative linear correlation (P <0.05), and similar linear correlation was also observed between STN and road density (RD) (P < 0.05). NO3--N content in soil and road density showed a negative correlation (P = 0.001). However, the correlation was not significant between NO3--N and the building density (P = 0.217) after being analyzed using different curve models. NH4+-N content and building density showed a significant negative linear correlation (P = 0.001), and a significant exponential correlation existed in NH4+-N content and the road density (P = 0.021). Therefore, a significant effect on the development of urban distribution of soil nitrogen was observed, that was potentially strengthened by increasing road lengths and building areas. It can be suggested that the monitoring and management of soil nitrogen should be enhanced, and the cycling of soil nitrogen, atmospheric nitrogen, and water nitrogen should be investigated in future studies. 参考文献 相似文献 引证文献

El jilguero dorado (Sicalis flaveola) modifica la estructura de sus vocalizaciones para adaptarse a hábitats urbanos

Urban and suburban ecosystems are areas that, despite of being modified by human activities, can sustain a large amount of biodiversity. Acoustic field alterations affect communication among animals, threatening the populations' stability dynamics. In birds, where acoustic communication take place at a certain distance, signals that reach the receptor may differ from those emitted, due to song degradation and acoustic pollution. In order to secure communication, species have to modify their vocalizations in different ways. We studied songs of the Saffron finch (Sicalis flaveola) at 2 sites with different levels of acoustic pollution. At the most polluted site, songs showed shorter trills with higher frequencies (max and min), and preludes with lower maximum frequencies. This is the first contribution on the vocalization's structure of the Saffron Finch at the study area, and provides new evidence on the effects that acoustic pollution produces on it. None of known song hypothesis was able to explain by itself the changes in song structure found in this study. Thus, this species adjusts its vocalizations to acoustic pollution in different ways simultaneously, depending on the species' inner capacities.

Ecosystem-based coastal zone management: A comprehensive assessment of coastal ecosystems in the Yangtze Estuary coastal zone

The comprehensive assessment of ecosystems is highlighted as one of the most important parts of ecosystem-based management (EBM) that must be addressed. In this paper, taking Chongming Dongtan coastal zone in the Yangtze Estuary as a case study, an example of the EBM approach to the assessment of ecosystem quality and degradation response to human impacts was presented. The spatio-temporal dynamics of the coastal ecosystems in the study area during the period 1990–2008 were analysed. The three main ecosystem types in the region: the natural wetland ecosystem, the agricultural ecosystem and the suburban ecosystem, were assessed for the period 2000–2008 through the application of an index of ecosystem degradation (EDI). The results indicated that large-scale reclamation and the invasion of an exotic plant Spartina alterniflora had threatened the ecosystem health of the natural wetland and caused its degradation. The production structure in agriculture needed to be improved and the amount of chemical fertilizer and pesticide application needed to be reduced, because they caused the degradation in the agricultural ecosystem. The area and population of the suburban ecosystem had grown substantially, which could not keep a pace with a healthy working and living environment. Based on these results, management strategies were proposed to minimize and/or reduce future degradation and impact. The methodology developed in this study is applicable elsewhere where coastal zones are under pressure.