Spatial patterns of lacustrine fish assemblages in a catchment of the Mississippi Alluvial Valley

Abstract

In the alluvial valley of the lower Mississippi River, floodplain lakes form isolated aquatic fragments that retain differing degrees of connectivity to neighbouring rivers. Within these floodplain lakes it was hypothesized that fish species composition, relative abundance, and biodiversity metrics would be shaped largely by aquatic connectivity within a catchment.Fish assemblages in 13 floodplain lakes (five on‐channel; eight off‐channel) were assessed with electrofishing in 2006–2012 in the Bear Creek catchment, Mississippi, USA. Bear Creek spans approximately 80 km before draining into the Yazoo River, a tributary of the Mississippi River.Fish assemblages in on‐channel and off‐channel lakes were different, and fish assemblages in on‐channel lakes were as a group more homogeneous than off‐channel lakes. Moreover, a longitudinal gradient in fish assemblages occurred in on‐channel lakes. The observed patterns in fish assemblages are linked largely to differing intensities in connectivity among lakes within the catchment. Lakes with irregular connections have greater individuality, whereas lakes with continuous or chronic connection are more similar. The wide variation in connectivity could be a key to the distinctive biodiversity of catchments and the focus of fish conservation programmes.Off‐channel floodplain lakes are among the first landscape elements to vanish as a consequence of agricultural development. These habitats tend to accumulate sediments at fast rates and are converted to agricultural land as soon as suitable drainage can be attained. Considering that off‐channel lakes with limited connectivity contribute greatly to the heterogeneity of fish assemblages, such losses pose great concerns to conservation of biodiversity. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Conservation of floodplain wetlands – out of sight, out of mind?

“…They can produce complex patterns of biodiversity. For example, fish assemblages on the Mississippi River floodplain lakes vary with the degree of connectivity (Andrews et al ., ).…”

“…They can produce complex patterns of biodiversity. For example, fish assemblages on the Mississippi River floodplain lakes vary with the degree of connectivity (Andrews et al, 2014). Many different organisms are highly dependent on the natural flooding and drying dynamics on the floodplain.…”

“…Earthworks such as levees protect agricultural crops, industry or urban development (Figure 1(b)). Floodplain wetlands can be the first wetlands supplied by a river to be destroyed (Andrews et al, 2014). Often, this leaves behind only remnant wetlands (Arthington et al, 2015).…”

Evaluation of Habitat Improvement Using Two-Dimensional Fish Habitat Modeling after the Connectivity Restoration in an Isolated Former Channel

“…본류 하도와 단절된 홍수터와 구하도는 본류와 에너지와 물질의 교환이 저해되어 물리 환경 이 변형된다 (Junk et al 1989, Schiemer 2000. 이 처럼 본류와 단절된 홍수터와 구하도의 환경에서는 어류 군집이 횡적 연결성이 확보된 곳에 비하여 교란 된 특성을 보이게 된다 (Erskine et al 2005, Andrews et al 2014. 따라서 본류 하도와 홍수터 또는 구하도 의 횡적 연결성 확보는 하천 생태계의 건강성을 유지 하고 개선하는데 매우 중요하다 (Tockner et al 1999).…”

Fish Community Structure of the Former Channel Isolated by Channelization in the Mangyeong River, Korea: Implications for Connectivity Restoration

“…특히 홍수터가 하도로부터 단절되면 수질 악화 및 토 사 퇴적이 발생하여 생물 서식지에 악영향을 미친다 (Miranda et al 2001). 또한 오랫동안 격리된 홍수터 와 구하도는 본류와 전혀 다른 환경으로 변하고 이에 따라 이곳의 어류 군집은 본류와는 크게 다른 특성을 보이게 된다 (Erskine et al 2005, Andrews et al 2014.…”