Post-European changes to the fluvial geomorphology of Bega catchment, Australia: implications for river ecology
Post-European changes to the fluvial geomorphology of Bega catchment, Australia: implications for river ecology
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DOI：
10.1046/j.1365-2427.1999.00397.x
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发表时间：
1999-06-01
影响因子：
2.7
通讯作者：
Brooks, A
中科院分区：
文献类型：
--
作者：
Brierley, GJ;Cohen, T;Brooks, A
1.在世纪中期欧洲的几十年干扰中，澳大利亚新南威尔士州南海岸的贝加流域的河流特征和行为发生了变化。评估了地貌变化对整个流域河流结构和功能的生态影响.在欧洲人定居的时候，贝加流域的许多水道是不连续的，沿着中上游有广泛的沼泽。经过一系列直接和间接的人类影响，渠道成为连续的中部和上部的集水区，作为广泛的山谷填充的基础上的悬崖被切割。沿着低地平原，河道加宽了300%以上，从根本上改变了河道与相邻洪泛区之间的关系。河流结构的地貌变化改变了整个贝加流域的栖息地。这种影响在源头河流中最不明显，但在悬崖底部以外的几乎所有河道中，沿着都是巨大的。河流结构的变化与河岸植被覆盖的改变直接相关，反之亦然。由于河流结构的变化，沿着大多数河流的河床底质口径（和供水量/供水率）都发生了变化。一系列间接的二次影响改变了沿着的生境生存能力。河流系统内的横向、纵向和纵向联系已经改变，影响到水、沉积物、有机物、营养物和其他生物相互作用的转移。河流结构中地貌变化的这些直接和间接后果表明，生态学家需要采用一种长期的、流域框架的观点来看待人类对河流生态系统的干扰。有效的、可持续的河道生态恢复取决于对地貌过程的理解和在集水区不同位置确定适当的河流结构。
1. Within a few decades of European disturbance in the mid-nineteenth century, river character and behaviour were transformed in Bega catchment on the south coast of New South Wales, Australia. Ecological impacts of geomorphic changes to river structure and function throughout the catchment are assessed.2. At the time of European settlement, many water courses in Bega catchment were discontinuous, with extensive swamps along middle and upper courses. Following a series of direct and indirect human impacts, channels became continuous in the middle and upper parts of the catchment, as extensive valley fills at the base of the escarpment were incised. Along the lowland plain, the channel widened by over 300%, fundamentally altering the relationship between the channel and its adjacent floodplain.3. Geomorphic changes to river structure have modified habitat availability throughout Bega catchment. The impacts have been least pronounced in headwater streams, but have been dramatic along virtually all river courses beyond the base of the escarpment.4. Changes in river structure have been directly related to altered riparian vegetation cover, and vice versa. As a consequence of changes to river structure, bed substrate calibre (and supply volume/rate) has been modified along most streams.5. A series of indirect, secondary impacts have modified habitat viability along river courses. Lateral, longitudinal and vertical linkages within the river system have been altered, affecting the transfer of water, sediment, organic matter, nutrients and other biotic interactions.6. These direct and indirect consequences of geomorphic changes in river structure suggest that ecologists need to adopt a longer-term, catchment-framed view of human disturbance to river ecosystems.7. Effective, sustainable ecological rehabilitation of river courses is dependent on an understanding of geomorphic processes and determination of appropriate river structure at differing positions in catchments.