Landscape composition, not connectivity, determines metacommunity structure across multiple scales

Ecography ◽  
2015 ◽  
Vol 39 (10) ◽  
pp. 932-941 ◽  
Author(s):  
Wade A. Ryberg ◽  
Lee A. Fitzgerald
Keyword(s):  
Multiple Scales ◽  
Landscape Composition ◽  
Metacommunity Structure

Exploring the Effects of Landscape Structure at Multiple Scales on River Water Characteristics in the Khorramabad and Chalus River basins

2021 ◽  
Author(s):  
Fatemeh Sadeghi Gorbandi ◽  
Hamid Torangzar ◽  
Ramin Zare ◽  
Javad Varvani ◽  
Abbas Ahmadi
Keyword(s):  
Water Quality ◽  
Landscape Structure ◽  
Human Activities ◽  
Urban Areas ◽  
Forest Cover ◽  
Multiple Scales ◽  
Landscape Composition ◽  
Riparian Buffer ◽  
Landscape Characteristics ◽  
Landscape Composition And Configuration

Abstract Background It is acknowledged that the landscape composition and configuration of land cover within a watershed could influence a watershed environmental and ecological quality. Therefore, rivers receive pollution from their surrounding landscape and the amount and intensity of this pollution are affected by the landscape structure around the river or within a watershed. Methods In this research, we estimated the relationship between landscape characteristics and water quality in two different basins. We used multiple stepwise regression analysis and redundancy analysis to explore the quantitative association between landscape metrics, at both the watershed and riparian buffer scales. Results The riparian buffer scales metrics were more effective in predicting water quality in comparison with the indices at the watershed scale. The landscape composition and configuration explained 80% of the variation in water quality at 100 m buffer, and the value decreased to 79% at 1000 m. At the 100 m buffer scale, ED of the forest, PLADJ, and MESH of urban areas in Khorramabad basin and AI of the forest, ED of urban, and SPLIT of agricultural lands were recognized as significant variables affecting the water quality in the Chalus basin. In other scales only metrics related to agriculture and urban were seen as dominant variables, indicating that these land-use classes are final determinatives in water quality changes in our study areas. Conclusion All dominant variables at each scale indicated a decreasing trend of the landscape impact on the water quality. Although in the Chalus basin human activities were insignificant, they had considerable effects on Chalus river quality, and urban and agriculture were recognized as dominant usages at all scales, implying that a large amount of forest cover cannot impede the effects of human activities in a basin.

scholarly journals Landscape-Level And Stand-Level Factors Play Diverse Roles During Different Periods of Dendroctonus Valens Invasion In North China

2021 ◽  
Author(s):  
Zhongyi Zhan ◽  
Lili Ren ◽  
Linfeng Yu ◽  
Zhiwen Guo ◽  
Yujie Liu ◽  
...  
Keyword(s):  
North China ◽  
Linear Models ◽  
Multiple Scales ◽  
Early Stage ◽  
Field Investigation ◽  
Landscape Composition ◽  
Invasive Pest ◽  
Pest Species ◽  
Invasive Pest Species ◽  
Landscape Level

Abstract In recent years, the red turpentine beetle (RTB), an invasive pest species, has caused extensive pine mortality in North China. Although some studies have theoretically clarified the interference mechanism of multi-level factors with the development of RTB damage, knowledge about this mechanism from the empirical research is still limited. The aim of this study was to determine whether the primary factors influencing RTB occurrence change during different periods of RTB invasion. Stand-level variables of sample plots were obtained through field investigation and the forest resource survey data including forest stand characteristics, topographic characteristics, and soil properties. Remote sensing classified images were to develop the characteristic variables related to landscape composition and configuration around the sample plots at multiple scales. Generalized linear models (GLMs) and generalized linear mixed models (GLMMs) were used to explore the relative importance of stand-level and landscape-level variables in explaining the severity of RTB damage. Result showed that two stand-level factors, aspect and canopy density, were the best predictors of damage in the early stage of RTB invasion. The landscape-level factor, the proportion of Chinese pine (Pinus tabuliformis) patches, was the main predictor of damage in the middle stage of RTB invasion. The most effective spatial scale at which RTB responded to landscape pattern was 250 m. With the increasing severity of RTB damage, the factors driving RTB invasion have shifted from the stand-level to the landscape-level. This calls for an urgent consideration of multi-scale processes to address the changing disturbance regimes in ecosystem management.

scholarly journals Differential Response of Migratory Guilds of Birds to Urbanization

2021 ◽  
Author(s):  
Michael T. Murphy ◽  
David C. Bailey ◽  
Nathanael I. Lichti ◽  
Laura A. Roberts
Keyword(s):  
Species Richness ◽  
Short Distance ◽  
Multiple Scales ◽  
Landscape Composition ◽  
Long Distance ◽  
Partial Migrant ◽  
Native Tree Species ◽  
Park Area ◽  
Surrounding Areas ◽  
Local Habitat

Abstract Species richness and density of native fauna in urban parks and greenspaces (“parks”) is often lower than in surrounding areas. Understanding the causes of these differences requires a hierarchical approach that integrates factors across multiple scales. In 2003 we surveyed bird communities in 48 forested parks in Portland, Oregon, USA, to identify the relative contributions of park size, shape, and connectivity, landscape composition, and variation in local habitat to differences in richness and density of long-distance migrant, short-distance/partial migrant, and resident birds. All surveyed parks contained highly structured understories comprised primarily of native vegetation and lacked development beyond trails. The bird guilds responded differently to environmental factors. Richness and density of long-distance migrants increased with park area and the abundance of small, mostly native, tree species. Resident species richness also increased with the abundance of small trees. Richness of residents and short-distance migrants was independent of park area, and resident density declined with increasing park area. Park shape, connectivity, and landscape composition did not contribute to differences in richness or density of different migratory guilds. Most long-distance migrants were forest-dependent species. An analysis of all forest-dependent species of all migratory guilds suggested that few exist in parks below 10 ha, and minimum area requirements for maintaining populations of forest-dependent species are estimated to be 30 to 40 ha. Without such parks most long-distance migrants would likely disappear from Portland’s landscape.

Effects of landscape composition on wetland occupancy by Blanding’s turtles (Emydoidea blandingii) as determined by eDNA and visual surveys

2021 ◽  
Author(s):  
Vincent K Fyson ◽  
Gabriel Blouin-Demers
Keyword(s):  
Multiple Scales ◽  
Environmental Dna ◽  
The United States ◽  
Landscape Composition ◽  
Freshwater Turtle ◽  
Great Lakes Region ◽  
Emydoidea Blandingii ◽  
Atlas Data ◽  
Wide Range ◽  
Surrounding Landscape

Habitat loss and degradation have led to the extinction of many species worldwide. The endangered Blanding’s turtle (Emydoidea blandingii (Holbrook, 1838)), a semi-aquatic freshwater turtle, occupies a wide range of wetlands and landscapes primarily in southeastern Canada and the Great Lakes region of the United States. We explore whether the probability of wetland occupancy by Blanding’s turtles is affected by the surrounding landscape. We used visual surveys, environmental DNA, and atlas data to document the presence of Blanding’s turtles in wetlands in Ottawa, Ontario, Canada. We tabulated landscape composition at multiple scales surrounding the wetlands to determine whether landscape composition can predict wetland occupancy. Generally, wetlands surrounded by forest and other undisturbed lands were most likely to harbour Blanding’s turtles, while those surrounded by more human-disturbed lands were least likely to harbour Blanding’s turtles. Larger wetlands and a high proportion of wetlands in the surrounding landscape also increased the probability of occupancy by Blanding’s turtles. Finally, older wetlands were more likely to be occupied by Blanding’s turtles. The ability to estimate a species’ probability of occupancy can aid in conservation efforts, such as critical habitat delineation.

Landscape composition and vole outbreaks: evidence from an eight year study of Arvicola terrestris

Ecography ◽  
2000 ◽  
Vol 23 (6) ◽  
pp. 659-668 ◽  
Author(s):  
E. Fichet-Calvet ◽  
B. Pradier ◽  
J. P. Quere ◽  
P. Giraudoux ◽  
P. Delattre
Keyword(s):  
Landscape Composition ◽  
Arvicola Terrestris

Environmental Studies and Ethnic Studies

2020 ◽  
Vol 43 (2) ◽  
pp. 9-16
Author(s):  
David N. Pellow
Keyword(s):  
Case Studies ◽  
Multiple Scales ◽  
Ethnic Studies ◽  
Environmental Studies ◽  
Potential Value

This article offers insights into conceptual, pedagogical, and programmatic crossings and conflicts between the fields of Environmental Studies and Ethnic Studies. It highlights both the important intersections between the two fields and their potential value, while also addressing the challenges posed in the development of programmatic collaborations. Utilizing case studies drawn from the author’s own experiences, the article’s focus is on harnessing the strengths and limitations of both fields to promote transformative knowledge and action at multiple scales.

The Role of Nonprofit Sector Networks as Mechanisms for Immigrant Political Participation

2012 ◽  
Vol 7 (1) ◽  
pp. 27-46 ◽  
Author(s):  
Luisa Veronis
Keyword(s):  
Political Participation ◽  
Nonprofit Organizations ◽  
Latin American ◽  
Social Action ◽  
Multiple Scales ◽  
Nonprofit Sector ◽  
Ethnographic Study ◽  
Immigrant Community ◽  
Immigrant Political Incorporation

Issues of immigrant political incorporation and transnational politics have drawn increased interest among migration scholars. This paper contributes to debates in this field by examining the role of networks, partnerships and collaborations of immigrant community organizations as mechanisms for immigrant political participation both locally and transnationally. These issues are addressed through an ethnographic study of the Hispanic Development Council, an umbrella advocacy organization representing settlement agencies serving Latin American immigrants in Toronto, Canada. Analysis of HDC’s three sets of networks (at the community, city and transnational levels) from a geographic and relational approach demonstrates the potentials and limits of nonprofit sector partnerships as mechanisms and concrete spaces for immigrant mobilization, empowerment, and social action in a context of neoliberal governance. It is argued that a combination of partnerships with a range of both state and non-state actors and at multiple scales can be significant in enabling nonprofit organizations to advance the interests of immigrant, minority and disadvantaged communities.

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