The Human Threat to River Ecosystems at the Watershed Scale: An Ecological Security Assessment of the Songhua River Basin, Northeast China

Abstract

Abstract:Human disturbances impact river basins by reducing the quality of, and services provided by, aquatic ecosystems. Conducting quantitative assessments of ecological security at the watershed scale is important for enhancing the water quality of river basins and promoting environmental management. In this study, China's Songhua River Basin was divided into 204 assessment units by combining watershed and administrative boundaries. Ten human threat factors were identified based on their significant influence on the river ecosystem. A modified ecological threat index was used to synthetically evaluate the ecological security, where frequency was weighted by flow length from the grids to the main rivers, while severity was weighted by the potential hazard of the factors on variables of river ecosystem integrity. The results showed that individual factors related to urbanization, agricultural development and facility construction presented different spatial distribution characteristics. At the center of the plain area, the provincial capital cities posed the highest level of threat, as did the municipal districts of prefecture-level cities. The spatial relationships between hot spot locations of the ecological threat index and water quality, as well as the distribution areas of critically endangered species, were analyzed. The sensitivity analysis illustrated that alteration of agricultural development largely changed the ecological security level of the basin. By offering a reference for assessing ecological security, this study can enhance water environmental planning and management.

The Spatial and Temporal Variability of Groundwater Vulnerability and Human Health Risk in the Limin District, Harbin, China

“…The rapid development of the study area contributed to the increasing of NH 4 -N pollution from 2006 to 2016. There are many sources of pollution distributed along the Songhua River and Hulan River, including both point and non-point sources, resulting in large emissions of NH 4 -N. These sources have lowered the water quality to a point where it has reached the surface water quality standards IV grade (>1 mg/L) of the PRC [50][51][52]. This may increase the risk of groundwater pollution with the decreasing river water quality [53,54].…”

Dampak Pemukiman Dan Kegiatan Di Tepi Sungai Terhadap Kualitas Air Sungai Baru Barat

“…Water quality is affected by land use and anthropogenic activities on river banks (Suratman and Norhayati, 2013) The decomposition of organic substances in the sediment of need oxygen , this will disrupting the lives of fish and an organism benthic (Catianis et al, 2018). Human activities that disturb the waters will affect the quality of the waters and services provided by, aquatic ecosystems (Shen et al, 2017).…”

Define–Investigate–Estimate–Map (DIEM) Framework for Modeling Habitat Threats

“…Similar index equations found in the literature were modified to be uniform. These equations include risk-based multispecies conservation value [10], threat score [21], ecological indicator ranking [6], ecological risk index [4,85], threat index [17,27,84], threat value [14], coastal vulnerability index [19], conversion threat index [32], relative threat factor severity index [23], endemism index [25], and habitat quality index [28]. Each of these index equations can be understood as habitat threat index equations on the basis of the broad definition of habitat threat.…”