Irrigation canals are newly created streams of semi-arid agricultural regions

Carlson, Erick A.; Cooper, David J.; Merritt, David M.; Kondratieff, Boris C.; Waskom, R.

doi:10.1016/j.scitotenv.2018.07.246

Cited by 21 publications

(13 citation statements)

References 68 publications

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“…Moreover, some microorganisms can come from adjacent terrestrial ecosystems (Bardgett et al, 2007; Schuette et al, 2010). The dispersal of soil bacteria can be an important driver of microbial community structure in aquatic ecosystems (Nepf, 2012; Taherzadeh et al, 2012). Thus, the variations of water-land interface caused by WLFs could influence the dispersal of soil bacteria to PYL, influencing microbial communities in the lake.…”

Section: Discussionmentioning

confidence: 99%

Distinct Bacterial Communities in Wet and Dry Seasons During a Seasonal Water Level Fluctuation in the Largest Freshwater Lake (Poyang Lake) in China

Ren

Zhang

et al. 2019

Front. Microbiol.

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Water level fluctuations (WLFs) are an inherent feature of lake ecosystems and have been regarded as a pervasive pressure on lacustrine ecosystems globally due to anthropogenic activities and climate change. However, the impacts of WLFs on lake microbial communities is one of our knowledge gaps. Here, we used the high-throughput 16S rRNA gene sequencing approach to investigate the taxonomic and functional dynamics of bacterial communities in wet-season and dry-season of Poyang Lake (PYL) in China. The results showed that dry-season was enriched in total nitrogen (TN), nitrate (NO 3 - ), ammonia (NH 4 + ), and soluble reactive phosphorus (SRP), while wet-season was enriched in dissolved organic carbon (DOC) and total phosphorus (TP). Bacterial communities were distinct taxonomically and functionally in dry-season and wet-season and the nutrients especially P variation had a significant contribution to the seasonal variation of bacterial communities. Moreover, bacterial communities responded differently to nutrient dynamics in different seasons. DOC, NO 3 - , and SRP had strong influences on bacterial communities in dry-season while only TP in wet-season. Alpha-diversity, functional redundancy, taxonomic dissimilarities, and taxa niche width were higher in dry-season, while functional dissimilarities were higher in wet-season, suggesting that the bacterial communities were more taxonomically sensitive in dry-season while more functionally sensitive in wet-season. Bacterial communities were more efficient in nutrients utilization in wet-season and might have different nitrogen removal mechanisms in different seasons. Bacterial communities in wet-season had significantly higher relative abundance of denitrification genes but lower anammox genes than in dry-season. This study enriched our knowledge of the impacts of WLFs and seasonal dynamics of lake ecosystems. Given the increasingly pervasive pressure of WLFs on lake ecosystems worldwide, our findings have important implications for conservation and management of lake ecosystems.

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Section: Discussionmentioning

confidence: 99%

Distinct Bacterial Communities in Wet and Dry Seasons During a Seasonal Water Level Fluctuation in the Largest Freshwater Lake (Poyang Lake) in China

Ren

Zhang

et al. 2019

Front. Microbiol.

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“…Our general expectation that wetlands at a short distance would favor the likelihood of crossing was confirmed in the overpasses. Wetlands initially represent a small percentage in most canal-irrigated areas (Carlson et al 2019). Our results suggest that even a slight increase in their proportion nearby can lead an overpass to increase its crossing probability.…”

Section: Primary Drivers Of Canal Crossings Through Overpassesmentioning

confidence: 69%

Carnivores cross irrigation canals more often through overpasses than through culverts

Azedo

Ilhéu

Santos

et al. 2021

Preprint

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As rainfall becomes scarcer or more erratic, we rely more on irrigation systems for water provision. Impacts of irrigation canals such as the barrier effect on wildlife movements are poorly documented. Although canal culverts and overpasses can be used by wildlife, little is known about their crossing patterns to guide barrier effect mitigation efforts. Over 7 years, we recorded medium-sized carnivore crossings by video-surveillance through 30 culverts and 28 overpasses in a large irrigation project in south-central Portugal. We examined the influence of the structures' features and landscape context on the likelihood of canal crossing. Culvert crossings were positively influenced by the proportion of nearby montado, a high nature value farming system. Overpass crossings were more likely in areas away from paved roads and with more nearby wetlands. Overpasses increased the crossing rates by about 11 % relative to culverts and both were crossed more often in landscapes with evenly distributed land uses. In the project area, 20% of the montado has recently transitioned to irrigated agriculture, and wetlands have increased by 43%. It is therefore plausible that the increase in the crossing rate of overpasses relative to culverts will be accentuated. Our study produced the first evidence of a contrast in crossing rates among irrigation canal crossing structures. We have shown that the landscape can be a driver of animal crossings but irrigation projects can in turn be transformative of the landscape. Broadly, the fact that the deployment of irrigation canals may favor some land uses over others creates a conundrum that needs careful consideration when planning barrier effect mitigation interventions.

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“…In rivers where the flow regime is regulated for irrigation, there are often strict flow schedules determined by downstream users, and these do not generally consider environmental objectives (Carlson et al 2019). The flow regime of Gunbower Creek reflects variable irrigation demand and typifies an altered hydrology more commonly observed below large dams and hydropower facilities, where short-term flow variability is magnified when there is high demand (Smokorowski et al 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Provision of environmental flows to maintain lotic refuges within irrigation systems, or within rivers and creeks used primarily as irrigation conduits, is an emerging theme for reestablishing fish assemblages in North America (Cowley et al 2007;Carlson et al 2019), France (Aspe et al 2016) and Japan (Onikura et al 2009). Within many natural rivers and other systems that are used as conduits for irrigation, a different approach to restoring an environmental flow regime is required because the starting flows have entirely consumptive objectives (Kingsford 2000).…”

Section: Introductionmentioning

confidence: 99%

From an irrigation system to an ecological asset: adding environmental flows establishes recovery of a threatened fish species

Stuart

Sharpe

Stanislawski

et al. 2019

Mar. Freshwater Res.

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Worldwide, riverine fish are the target of environmental water because populations have declined in lotic river habitats following river regulation. Murray cod is an endangered Australian riverine fish with remaining populations associated with lotic river reaches with instream habitat, including some creeks operated as part of irrigation systems. Our objectives were to develop a life history model, apply the building block method of environmental flows to enhance the abundance of juvenile Murray cod and promote population recovery. From 2008 to 2018 we evaluated changes to Murray cod juvenile abundance before and after implementation of a perennial environmental flow regime that began in 2013. During the first year of the environmental flow, larvae were collected as evidence of spawning. Murray cod abundance can be enhanced with environmental flows that target: (1) an annual spring spawning or recruitment flow with no rapid water level drops; (2) maximising hydrodynamic complexity (i.e. flowing habitats that are longitudinally continuous and hydrodynamically complex); and (3) an annual base winter connection flow. Recognition that incorporating hydraulics (water level and velocity) at fine and coarse time scales, over spatial scales that reflect life histories, provides broader opportunities to expand the scope of environmental flows to help restore imperilled fish species in regulated ecosystems.

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Irrigation canals are newly created streams of semi-arid agricultural regions

Cited by 21 publications

References 68 publications

Distinct Bacterial Communities in Wet and Dry Seasons During a Seasonal Water Level Fluctuation in the Largest Freshwater Lake (Poyang Lake) in China

Distinct Bacterial Communities in Wet and Dry Seasons During a Seasonal Water Level Fluctuation in the Largest Freshwater Lake (Poyang Lake) in China

Carnivores cross irrigation canals more often through overpasses than through culverts

From an irrigation system to an ecological asset: adding environmental flows establishes recovery of a threatened fish species

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