scholarly journals Multi-Scale Ecological Connectivity Dynamics Associated With Hydropower Station: A Case Study in the Lancang River Valley

2021 ◽  
Vol 8 ◽  
Author(s):  
Shiliang Liu ◽  
FangFang Wang ◽  
Li Deng ◽  
Yuhong Dong ◽  
Yixuan Liu

Dam construction is a major threat to terrestrial ecological processes that exhibit spatial variation. As an effective indicator of species movements at large scales, the dynamics of forest landscape connectivity for the dispersal abilities of local species such as primates both upstream and downstream of the Manwan hydropower station were compared in three periods: before, during, and after dam construction (in 1974, 1988, and 2004, respectively). The equivalent connected area (ECA) index which was modified from the probability of connectivity (PC) index based on the graph theory was applied in this study. We used this method to analyze the spatial and temporal changes in the overall forest landscape connectivity due to dam construction. The results showed that forest connectivity decreased after dam construction. The forest connectivity upstream was much greater than that downstream in 1974 but was lower in 1988 and 2004. The importance of connectivity increased with increasing dispersal distance. Only 8, 12, and 18% of forest patches of small area exhibited changes in 1974, 1988, and 2004, respectively. Most of the large habitat patches (i.e., those with dECA values >50%) remained stable, and the greatest patch changes were found at a dispersal distance of 400 m in all three periods. These large forest patch changes often occurred near the boundary of the study area. The Betweenness Centrality indicator, which identifies patches as stepping stones while accounting for ecological processes and biological flows at a larger scale, indicated that some habitat patches near Manwan Dam acted as stepping stones in maintaining the forest connectivity. Furthermore, rank correlations between the forest patch area and the three dPC (intra, flux, connector) fractions indicated that the dPCflux indicator can be used to measure the prioritization of habitat patches.

2020 ◽  
Author(s):  
Jingjing Zhang ◽  
Jennifer L. Pannell ◽  
Bradley S. Case ◽  
Graham Hinchliffe ◽  
Margaret C. Stanley ◽  
...  

AbstractUnderstanding how spatial heterogeneity affects movement and dispersal is critical for maintaining functional connectivity in agroecosystems. Least-cost path models are popular conservation tools to quantify the cost of a species dispersing though the landscapes. However, the variability of species in life history traits and landscape configurations can affect their space-use patterns and should be considered in agroecosystem management aiming to improve functional biodiversity. In this study, we modelled the connectivity properties of native species on a real agroecosystem landscape dominated by sheep and beef farming in north Canterbury, New Zealand, where the recovery of native bird population is desired. We chose two species to act as case studies that were contrasting in their mobility: New Zealand pigeon/kererū (Hemiphaga novaeseelandiae; highly mobile) and southern brown kiwi/tokoeka (Apteryx australis; flightless). Networks of the least-cost paths of kererū and tokoeka were constructed based on their habitat preferences and movement capacities, and we compared and contrasted the connectivity properties and network topographies of their networks. We then compared the network metrics of western side (higher density of forest) with the eastern side (dominated by grazed grassland) of the study area where the vegetation composition was vastly different for both species. The results shown three variables were the most important contributors to the structure of the dispersal networks: the nature of the matrix, spatial structure of vegetation patches, and the gap-crossing ability of the study species. Tokoeka were able to utilise smaller habitat patches as stepping-stones for dispersal, while kererū can select more preferred habitat patches due to their high movement capacity. In contrast to the eastern side, we observed the western/forested side to have more, and stronger, links among habitat patches for both species, due to the presence of several large patches of native forest. Our work suggested that one size does not fit all, rather, conservation strategies that account for species’ life histories and movement traits are required to identify and preserve a connected ecological network.


2017 ◽  
Vol 26 (14) ◽  
pp. 3465-3479 ◽  
Author(s):  
Lorena P. Herrera ◽  
Malena C. Sabatino ◽  
Florencia R. Jaimes ◽  
Santiago Saura

2021 ◽  
Vol 13 (6) ◽  
pp. 3473
Author(s):  
Yong Lai ◽  
Guangqing Huang ◽  
Shengzhong Chen ◽  
Shaotao Lin ◽  
Wenjun Lin ◽  
...  

Anthropogenic land-use change is one of the main drivers of global environmental change. China has been on a fast track of land-use change since the Reform and Opening-up policy in 1978. In view of the situation, this study aims to optimize land use and provide a way to effectively coordinate the development and ecological protection in China. We took East Guangdong (EGD), an underdeveloped but populous region, as a case study. We used land-use changes indexes to demonstrate the land-use dynamics in EGD from 2000 to 2020, then identified the hot spots for fast-growing areas of built-up land and simulated land use in 2030 using the future land-use simulation (FLUS) model. The results indicated that the cropland and the built-up land changed in a large proportion during the study period. Then we established the ecological security pattern (ESP) according to the minimal cumulative resistance model (MCRM) based on the natural and socioeconomic factors. Corridors, buffer zones, and the key nodes were extracted by the MCRM to maintain landscape connectivity and key ecological processes of the study area. Moreover, the study showed the way to identify the conflict zones between future built-up land expansion with the corridors and buffer zones, which will be critical areas of consideration for future land-use management. Finally, some relevant policy recommendations are proposed based on the research result.


Author(s):  
Kimberly A. With

Landscape connectivity is essential for maintaining ecological flows across landscapes. Processes as diverse as dispersal; gene flow; the flow of water, materials and nutrients; the spread of invasive species, diseases, or pests; or the spread of disturbances like fire, are all potentially influenced by the connectivity of different land covers and land uses. Landscape connectivity can be defined structurally as well as functionally. Landscape connectivity may therefore be treated as either an independent variable, in terms of studying how landscape connectivity influences ecological flows, or as a dependent variable in which landscape connectivity emerges as a consequence of how species or ecological flows interact with landscape structure. This chapter thus explores the different scales and ways in which connectivity can be measured and studied, providing a bridge between the previous chapter on landscape pattern analysis and the chapters that follow on the effects of landscape pattern on ecological processes.


1999 ◽  
Vol 5 (2) ◽  
pp. 158 ◽  
Author(s):  
Chris Norwood

Increasing demand for resources through a growing world population and the development of consumer led economies has led to large-scale habitat modification. One of the most disturbing aspects of these changes is the loss of biodiversity. Conservation biology as a discipline seeks to counteract or minimize the loss of biodiversity. Management is an Important aspect in achieving this goal. One concept used in Wildlife management and conservation is that of landscape linkages. Linkages are aimed at faclhtatmg .the connectivity for species, communities or ecological processes. There are many types of linkages in the landscape; both natural and human induced. Covered in this book are linkages such as greenways, dispersal corridors, riparian remnants, wildlife corridors, stepping stones, hedgerows and road underpasses. Linkages range in scale from small patches of old-growth forest in a forest mosaic to migratory routes for birds across and between continents.


2012 ◽  
Vol 90 (2) ◽  
pp. 222-236 ◽  
Author(s):  
C.E. Rizkalla ◽  
R.K. Swihart

Measuring connectivity in fragmented landscapes remains a central problem in ecology. Connectivity metrics range from descriptors of landscape structure to direct observations of a species’ ability to move to and colonize a forest patch. We constructed individual-based spatially explicit population models for a guild of forest rodents in Indiana to test the ability of structural and actual, or behavioral, measures of connectivity to predict patch and landscape occupancy and abundance. Model accuracy was assessed using comparisons with data from trapping studies. Predicted abundances within patches correlated with empirical data for five out of six species, but predicted patterns of patch occupancy corresponded with observations for only one species. Discrepancies may be due to inaccurate parameter values or the absence from the models of ecological processes such as conspecific attraction and competition. Nonetheless, the models demonstrated the utility of patch immigration as a measure of connectivity in explaining population abundance in fragmented landscapes. We discuss potential methods of collecting these behavior-based data.


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