scholarly journals Microhabitat characteristics related to seasonal roost switching: implications from a threatened and introduced cockatoo species in an urban landscape

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sifeng Wang ◽  
L. M. Chu
Keyword(s):  
Land Use ◽  
Environmental Factors ◽  
Human Disturbance ◽  
Repeated Measures ◽  
Urban Landscape ◽  
Urban Environments ◽  
Behavioural Adaptation ◽  
Land Use Types ◽  
Chi Squared ◽  
Different Seasons

Abstract Background Communal roosting is a common avian social behaviour, which potentially provides foraging benefits, predation avoidance or thermoregulation in birds. To identify the crucial environmental factors associated with roost site selection, most studies have focused on the comparison of physical characteristics between roosts and non-roosts. However, the differences among roosts have usually been neglected and the causes of roost switching have seldom been investigated. Methods To explore the variations among roost sites and assess the most influential environmental factors related to seasonal roost switching, we conducted a 105-day observation on an introduced population of critically endangered Yellow-crested Cockatoo (Cacatua sulphurea) in an urban environment in Hong Kong from 2014 to 2016. We identified seven roost sites that were occupied in different seasons and then measured their microhabitat characteristics in terms of land use types, human disturbance and microclimate temperature. To quantify these differences, we used Pearson’s chi-squared test, partial least squares determinant analysis (PLS-DA) and one-way repeated measures ANOVA, respectively. Results Our results distinguished roost sites occupied in three seasons, i.e. spring, summer and winter roosts, using several microhabitat characteristics. The land use types were significantly associated with roosts, where spring roosts were usually located in tree-dominated areas, which are the major feeding grounds. The discriminant analysis on human disturbance variables indicated that summer roosts were positively associated with night illumination. The microhabitat temperatures of winter roosts were significantly higher than those of most other roosts on cold nights. Conclusions The results highlighted significant variations among roosts, and seasonal roost switching was likely driven by specific microhabitat characteristics of each roost site, such as microclimate. It also helps us understand the behavioural adaptation of birds to urban environments.

scholarly journals Herbert Sukopp – an inspiring pioneer in the field of urban ecology

2020 ◽  
Vol 23 (3) ◽  
pp. 445-455 ◽  
Author(s):  
Ingo Kowarik
Keyword(s):  
Land Use ◽  
Urban Ecology ◽  
Online Survey ◽  
Modern Science ◽  
Scientific Work ◽  
Urban Environments ◽  
Land Use Types ◽  
90Th Anniversary ◽  
The City ◽  
Further Development

Abstract Urban ecology is a well-established integrative discipline with many historical roots. One of the eminent pioneers of urban ecology is the German ecologist Herbert Sukopp, who works in Berlin since the late 1950s and is often referred to as the founder of the "Berlin School of Urban Ecology". On the occasion of his 90th anniversary in 2020, this paper aims to recognize and commemorate the major contributions of Sukopp to the field of urban ecology, based on his scientific work and on results of an online survey on his perception in the international scientific community. Sukopp’s contributions were groundbreaking for the establishment of urban ecology. Specifically, his work furthered: (1) the performance of comprehensive biodiversity studies across all land-use types within the city, in relation to the specifics of urban environments; (2) the establishment of modern approaches of nature conservation in cities and their integration into all land-use types, and the city as a whole; (3) the formation of a multidisciplinary conceptual basis of urban ecology as a modern science, with combined scientific and applied perspectives, ultimately aiming at the preservation and further development of nature within cities for the benefit of urban residents. Herbert Sukopp is thus an important and inspiring pioneer in the field of urban ecology.

The response of mixed-species bird flocks to anthropogenic disturbance and elevational variation in southwest China

The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Liping Zhou ◽  
Indika Peabotuwage ◽  
Hao Gu ◽  
Demeng Jiang ◽  
Guohua Hu ◽  
...  
Keyword(s):  
Land Use ◽  
Human Disturbance ◽  
Species Interactions ◽  
Southern China ◽  
Mixed Species ◽  
Biodiversity Crisis ◽  
Land Use Types ◽  
Mixed Species Flocks ◽  
Elevational Variation ◽  
Forest Buffer

Abstract Avian mixed-species flocks (MSFs) are an important example of species interactions threatened by the biodiversity crisis. They are found throughout the world in forested habitats but are generally reduced in size or frequency by human disturbance. In southern China, a unique MSF system is led by several species of closely- related fulvettas (Alcippe morrisonia, A. hueti, and A. davidi). Our objective was to understand how this system is distributed across elevational gradients, especially moving west into the Hengduan Mountains, and how it responds to human disturbance. We sampled leadership and composition of 375 MSFs over 2 yr in and surrounding 5 nature reserves in Guangxi Zhuang Autonomous Region and Yunnan Province, with transects placed in different land use types—protected forest, buffer areas, or agriculture—and ranging from 400 to 3,200 m. We also sampled birds outside of MSFs. We found MSFs led by fulvettas (A. fratercula and A. davidi) in forests across the region up to 2,900 m. Elevation was not a significant influence on MSF size or prevalence in models that also included land use. We found that MSFs were encountered at only one-third of the frequency in agriculture as in forest, and had strongly different composition and leadership. Although MSFs in buffer areas were more similar to those in forest, birds in buffer areas had lower flocking propensity, different flock leaders, and less complex social networks. In particular, buffer transects that were seeded pine had low numbers of fulvetta-led MSFs and forest specialists in MSFs. In the future, it is important to understand which vegetational characteristics allow MSFs, particularly fulvetta-led MSFs, to persist in buffer habitats.

Human-disturbed landscapes: effects on composition and integrity of riparian woody vegetation in the Tagus River basin, Portugal

2005 ◽  
Vol 32 (1) ◽  
pp. 30-41 ◽  
Author(s):  
FRANCISCA C. AGUIAR ◽  
MARIA TERESA FERREIRA
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Environmental Factors ◽  
Human Disturbance ◽  
Riparian Vegetation ◽  
Woody Vegetation ◽  
Small Scale ◽  
Riparian Ecosystems ◽  
Average Width ◽  
The Impact

Human activities within fluvial corridors and surrounding landscapes have persistently stressed riparian ecosystems, particularly in Iberian Mediterranean-type streams. The impact of human disturbance relative to natural environmental factors in shaping riparian vegetation is still poorly understood. Both regional variables (such as altitude and precipitation), and site-specific characteristics (such as substrate and riverbank modifications) were analysed as potential determinants of riparian vegetation patterning to determine the relative influences of the diverse land-use types and environmental factors on the composition (including floristic species richness and percentage cover of trees, shrubs and woody climbers) and integrity (width of riparian woods and patterns of longitudinal continuity) of riparian woods in eight river basins of the Tagus fluvial system (Portugal). There was patchy establishment of riparian woods, with generally low average width and low species richness, as well as significant inter-basin differences and upstream-downstream variations in riparian features. Species distribution was clearly determined by environmental factors, such as human disturbance on the riverbanks and geological background, and the environmental variables and the land use in the river valley partially explained the integrity of riparian woody vegetation. The results highlight the predictive capability of reach-level features; it appears that, linked with the geomorphological and climate context, small-scale human disturbances on riparian corridors play a major role in explaining the remaining biological variability.

scholarly journals Environmental and Anthropogenic Factors Shape Major Bacterial Community Types Across the Complex Mountain Landscape of Switzerland

2021 ◽  
Vol 12 ◽  
Author(s):  
Johanna Mayerhofer ◽  
Daniel Wächter ◽  
Pierluigi Calanca ◽  
Lukas Kohli ◽  
Tobias Roth ◽  
...  
Keyword(s):  
Land Use ◽  
Environmental Factors ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bipartite Network ◽  
Network Analyses ◽  
Soil Bacterial Communities ◽  
Land Use Types ◽  
Biogeographic Regions ◽  
Soil Bacterial

Mountain areas harbor large climatic and geographic gradients and form numerous habitats that promote high overall biodiversity. Compared to macroorganisms, knowledge about drivers of biodiversity and distribution of soil bacteria in mountain regions is still scarce but a prerequisite for conservation of bacterial functions in soils. An important question is, whether soil bacterial communities with similar structures share environmental preferences. Using metabarcoding of the 16S rRNA gene marker, we assessed soil bacterial communities at 255 sites of a regular grid covering the mountainous landscape of Switzerland, which is characterized by close location of biogeographic regions that harbor different land-use types. Distribution of bacterial communities was mainly shaped by environmental selection, as revealed by 47.9% variance explained by environmental factors, with pH (29%) being most important. Little additional variance was explained by biogeographic regions (2.8%) and land-use types (3.3%). Cluster analysis of bacterial community structures revealed six bacterial community types (BCTs), which were associated to several biogeographic regions and land-use types but overall differed mainly in their preference for soil pH. BCT I and II occurred at neutral pH, showed distinct preferences for biogeographic regions mainly differing in elevation and nutrient availability. BCT III and IV differed only in their preferred soil pH. BCT VI occurred in most acidic soils (pH 3.6) and almost exclusively at forest sites. BCT V occurred in soils with a mean pH of 4 and differed from BCT VI in preference for lower values of organic C, total nitrogen and their ratio. Indicator species and bipartite network analyses revealed 3,998 OTUs associating to different levels of environmental factors and BCTs. Taxonomic classification revealed opposing associations of taxa deriving from the same phyla. The results revealed that pH, land-use type, biogeographic region, and nutrient availability were the main factors shaping bacterial communities across Switzerland. Indicator species and bipartite network analyses revealed environmental preferences of bacterial taxa. Combining information of environmental factors and BCTs yielded increased resolution of the factors shaping soil bacterial communities and provided an improved biodiversity framework. OTUs exclusively associated to BCTs provide a novel resource to identify unassessed environmental drivers.

scholarly journals Evaluating the Variability of Urban Land Surface Temperatures Using Drone Observations

2019 ◽  
Vol 11 (14) ◽  
pp. 1722 ◽  
Author(s):  
Joseph Naughton ◽  
Walter McDonald
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Environmental Health ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Urban Land ◽  
Urban Environments ◽  
Surface Temperatures ◽  
Land Use Types ◽  
Land Surface Temperatures

Urbanization and climate change are driving increases in urban land surface temperatures that pose a threat to human and environmental health. To address this challenge, we must be able to observe land surface temperatures within spatially complex urban environments. However, many existing remote sensing studies are based upon satellite or aerial imagery that capture temperature at coarse resolutions that fail to capture the spatial complexities of urban land surfaces that can change at a sub-meter resolution. This study seeks to fill this gap by evaluating the spatial variability of land surface temperatures through drone thermal imagery captured at high-resolutions (13 cm). In this study, flights were conducted using a quadcopter drone and thermal camera at two case study locations in Milwaukee, Wisconsin and El Paso, Texas. Results indicate that land use types exhibit significant variability in their surface temperatures (3.9–15.8 °C) and that this variability is influenced by surface material properties, traffic, weather and urban geometry. Air temperature and solar radiation were statistically significant predictors of land surface temperature (R2 0.37–0.84) but the predictive power of the models was lower for land use types that were heavily impacted by pedestrian or vehicular traffic. The findings from this study ultimately elucidate factors that contribute to land surface temperature variability in the urban environment, which can be applied to develop better temperature mitigation practices to protect human and environmental health.

scholarly journals Leaf Functional Traits Vary in Urban Environments: Influences of Leaf Age, Land-Use Type, and Urban–Rural Gradient

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuebo Su ◽  
Bowen Cui ◽  
Yunjian Luo ◽  
Jia Wang ◽  
Xuming Wang ◽  
...  
Keyword(s):  
Land Use ◽  
Functional Traits ◽  
Stomatal Density ◽  
Leaf Age ◽  
Urban Environments ◽  
Land Use Type ◽  
Leaf Functional Traits ◽  
Land Use Types ◽  
Urban Rural ◽  
The City

An increasing number of studies have focused on the response and adaptation of plants to urbanization by comparing differences in leaf functional traits between urban and rural sites. However, considerable uncertainties remain because differences in land-use type have not frequently been taken into account when assessing the effect of urbanization on leaf traits. In this study, we sampled the needles of Chinese pine (Pinus tabuliformis Carr.) in areas with three land-use types (roadsides, parks, and neighborhoods) along an urban–rural gradient in Beijing, China to determine the effect of urbanization on leaf functional traits. There were significant differences in the values of leaf functional traits between the needles of the current and previous year and across land-use types. Pines growing on roadsides had leaves with smaller length, width, and area, as well as lower stomatal density, compared with those growing in parks and neighborhoods. This implies that on roadsides, plant capacity to acquire resources (e.g., light and carbon dioxide) was degraded. Stomatal density, leaf width, and leaf P concentration increased with increasing distance from the city center, while leaf K concentration decreased with increasing distance from the city center. Importantly, there were significant differences in the urban–rural gradient of leaf functional traits between leaves of different ages, and across land-use types. Leaf age was the most important factor influencing leaf nutrient traits, while land-use type was the most important factor influencing leaf morphological traits in urban environments. Thus, considering the effects of the plant characteristic and land-use type on traits is important for assessing the urban–rural gradients of plant functional traits.

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