Ecological Connectivity Networks for Multi-Dispersal Scenarios Using UNICOR Analysis in Luohe Region, China
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230 Full Paper Ecological Connectivity Networks for Multi-dispersal Scenarios Using UNICOR Analysis in Luohe Region, China Guifang Wang1, Samuel A. Cushman2, Ho Yi Wan3, Huawei Li4,5, Zita Szabó5, Dongge Ning5, Sándor Jombach5 1Institute of Landscape Architecture, Urban Planning and Garden Art, Hungarian University of Agriculture and Life Sciences, Budapest/Hungary · [email protected] 2USDA Forest Service, Rocky Mountain Research Station, AZ/USA 3Department of Wildlife, Humboldt State University, CA/USA 4Department of Landscape Architecture, Henan Agricultural University, Zhengzhou/China 5Institute of Landscape Architecture, Urban Planning and Garden Art, Hungarian University of Agri- culture and Life Sciences, Budapest/Hungary Abstract: Habitat loss and fragmentation are increasingly disrupting natural ecosystems across the world, especially in areas that have experienced extensive recent anthropogenic land use change. Eval- uating multi-dispersal scenarios of ecological connectivity networks provides an important means to evaluate how dispersal ability influences the prediction of optimal ecological networks. Few examples exist of the dependence of connectivity networks on the scale of dispersal ability used in the analysis. In this study, we performed supervised classification to map land use types using Landsat 8 imagery, then used Morphological Spatial Pattern Analysis and Conefor to identify important core areas for bi- odiversity, and finally used UNICOR to simulate the resistant kernel and factorial least-cost path con- nectivity networks. Our main results show: (1) Species with dispersal abilities of ≤ 2 km showed gen- erally low connectivity in most areas, with core areas of high connectivity mainly in Luohe central area, Linying county and Wuyang county, and major corridors were restricted within the Luohe central area, Linying county and Wuyang county. Species with dispersal abilities of 4 km and 8 km showed a net- work of connectivity with multiple pathways connecting the interior of the study area. Finally, species with dispersal abilities of ≥ 16 km showed high connectivity levels and appeared fairly insensitive to current configurations of human development in the study area. (2) Intensely developed areas may be obstructing species movements into the southeastern and northeastern parts of the region. The green space along roads and rivers may facilitate movement and promote connectivity. In future planning, planners should consider ways to enhance ecological connectivity networks, such as identified in this study, for conserving species with limited dispersal range. Keywords: Ecological network, dispersal ability, resistant kernel, factorial least-cost path 1 Introduction With the rapid increase of industrialization and urbanization, natural ecosystems and ecosys- tem services in China are experiencing landscape fragmentation and degradation due to urban sprawl (PENG et al. 2018, UPADHYAY et al. 2017). In effect, landscape fragmentation and degradation cause habitat loss and impact the movement of species (CLOSSET-KOPP et al. 2016). Thus, maintaining landscape connectivity and mitigating the fragmentation of habitat may be critical for ecological processes such as gene flow, dispersal and migration (RUDNICK et al. 2012). Ecological Networks (ENs) can provide conservation solutions to mitigate the damage caused by intensified land use (JONGMAN 2008) by promoting landscape connectiv- ity and reducing landscape fragmentation (UPADHYAY et al. 2017) through facilitating gene Journal of Digital Landscape Architecture, 6-2021, pp. 230-244. © Wichmann Verlag, VDE VERLAG GMBH · Berlin · Offenbach. ISBN 978-3-87907-705-2, ISSN 2367-4253, e-ISSN 2511-624X, doi:10.14627/537705020. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by-nd/4.0/). G. Wang et al.: Ecological Connectivity Networks for Multi-dispersal Scenarios 231 flow, migration, dispersal of species (RICOTTA et al. 2000). Therefore, an optimized ecolog- ical network (EN) spatial pattern is of great significance for the sustainable development of urban and rural ecosystems (RUIZ-GONZÁLEZ et al. 2014). While several studies have assessed ecological network connectivity for species of conser- vation concern in many parts of the world (e. g., CUSHMAN et al. 2014 and 2016, KASZTA et al. 2019 and 2020, ASHRAFZADEH et al. 2020), relatively few have explicitly evaluated the sensitivity of these network predictions to the dispersal ability of focal organisms. This is particularly important, as dispersal ability has been shown to be the most important factor affecting functional connectivity in several taxonomic groups (e. g., CUSHMAN et al. 2010a, ASH et al. 2020). The few ecological network assessments that have explicitly assessed the effects of dispersal ability have found strong influences on predictions and conclusions re- garding conservation recommendations (e. g., CUSHMAN et al. 2010a, 2013a and 2016, RIORDAN et al. 2016, MACDONALD et al. 2018). Despite being one of the largest nations in the world, with the world’s largest population and one of the fastest-growing economies, there have been relatively few landscape-scale assess- ments of the structure, function and optimality of ecological networks completed in China. In 1979, Three-North Shelterbelt was the first exploration of ecological construction to im- prove the desert environment in China. After the 1990s, the Chinese government announced a set of urbanization policies which resulted in the creation of vast urban development, but also the first coordinated efforts to enhance green areas for health, aesthetic and biodiversity values. These included initiatives such as Landscape Garden City, Forest City, Ecological Garden City and City in the Park. In recent years, national planning in China has increasingly considered the security and health of ecological processes to protect ecosystems systemati- cally (PENG et al. 2018). Luohe city was designated a National Landscape Garden City in 2002 and National Forest City in 2010, which have directed development to enhance green open space for the physical and mental health of residents. Its developments of ecological connectivity networks and green urbanization represent an example of a national focus on green development. While Luhoe is a focus of green development, there has been relatively little quantitative and ana- lytical work to assess the effectiveness and optimize the future development of green infra- structure in the region. Little is known about how multi-dispersal scenarios can influence the ecological connectivity network in the Luohe region. To provide this critical information, we applied the UNIversal CORridor and network simulation model (UNICOR) (LANDGUTH et al. 2012) to map the ecological connectivity networks for multi-dispersal scenarios in Luohe region, China, where intensive construction activities over the past several decades have re- sulted in massive and rapid land use change and reduction in natural ecosystems and habitats. We have three goals: (1) to map and compare resistant kernel maps at multi-dispersal scenar- ios, (2) to map and compare factorial least-cost paths at multi-dispersal scenarios, and (3) to rank conservation orders of ecological connectivity network. 2 Study Area Luohe region is located in central Henan province (113º27′ – 114º16′E, 33º24′ – 33º59′N) and is characterized by varied topography of plateau and hills in the west and lower riverine valleys in the east. The total municipal territory of Luohe region is 2617 km2, including 232 Journal of Digital Landscape Architecture · 6-2021 Yuanhui district, Yancheng district, Shaoling district, Wuyang county and Linying county (Figure 1), spanning 76 km from east to west and 64 km from north to south. Luohe city is developed along Sha and Li rivers which meet in the central area. Fig. 1: Location of Luohe region within Henan Province 3 Methods 3.1 Multi-dispersal Scenarios and Ecological Source Selection We evaluated connectivity network predictions across seven dispersal thresholds, including 1 km, 2 km, 4 km, 8 km, 16 km, 32 km, 64 km (MATEO SANCHEZ et al. 2013), which follows power two scaling to span the scale of the study area and the potential dispersal ability of most native species. In this way, we evaluated a general sensitivity of ecological network predictions to dispersal for species associated with green space. 3.2 Remotely Sensed Image Acquisition and Preprocessing 1) Image acquisition. We downloaded two Landsat 8 images on June 14, 2019 and July 7, 2019 (Resolution: 30 m; Coordinate system: WGS_1984_UTM_zone_50N and WGS_ 1984_UTM_zone_49N respectively) from EarthExplorer – USGS (INTERNET 1. 2021). At that time the wheat in Henan province was fully mature, with a distinctive yellow color, and as green space is characterized by high reflectance in the green wavelengths, it is possible to distinguish green space and farmland spectrally with great accuracy. 2) Image preprocessing. In ENVI 5.3, we used Radiometric Calibration and FLAASH Atmospheric Correction functions to produce two maps, then clipped them using the boundary of the Luohe region. Because the whole Luohe region involves two images, classification accuracy was not high at the edge of the maps when we mosaicked them. Classifying them first then mosaicking them solved the problem. G. Wang et al.: Ecological Connectivity Networks for Multi-dispersal Scenarios 233 3) Classification.