Potential of submerged macrophytes to support food webs in lowland agricultural streams

Submerged plants are often abundant in lowland streams in agricultural landscapes, but little is known of their role in stream ecosystems compared to riparian vegetation. We investigated the importance of submerged macrophytes as a basal resource of food webs in stream reaches with good and poor riparian vegetation condition, using mixing model analysis with stable carbon and nitrogen isotopes. Epilithic periphyton and terrestrial detritus were important basal resources in good condition reaches, although where macrophytes were present they contributed to food webs. Higher assimilation of either the macrophyte Cycnogeton huegelii or conspicuous epiphytes on C. huegelii leaves was associated with poor riparian condition. Where Potamogeton ochreatus and Ottelia ovalifolia occurred in poor condition reaches, these macrophytes contributed moderately to the food web, but were probably of greater importance as substrates for epiphytic algae. Mixing models indicated invertebrates commonly had generalist feeding strategies, feeding on the most available resource at each reach. Thus, where riparian vegetation is limited, submerged macrophytes may support opportunistic consumers both directly and as a substrate for epiphytes, thereby partially compensating for the loss of allochthonous resources in lowland agricultural streams.

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Association of reduced riparian vegetation cover in agricultural landscapes with coarse detritus dynamics in lowland streams

Marine and Freshwater Research ◽

10.1071/mf08012 ◽

2008 ◽

Vol 59 (11) ◽

pp. 998 ◽

Cited By ~ 21

Author(s):

D. J. Reid ◽

P. S. Lake ◽

G. P. Quinn ◽

P. Reich

Keyword(s):

Canopy Cover ◽

Agricultural Landscapes ◽

Allochthonous Input ◽

Lowland Streams ◽

South Eastern ◽

Eastern Australia ◽

Agricultural Streams ◽

Standing Stocks ◽

Allochthonous Detritus ◽

South Eastern Australia

Studies were conducted on streams flowing through agricultural floodplains in south-eastern Australia to quantify whether reductions in riparian canopy cover were associated with alterations to the input and benthic standing stocks of coarse allochthonous detritus. Comparisons were made among three farmland reaches and three reaches within reserves with intact cover of remnant overstorey trees. Detritus inputs to these reaches were measured monthly over 2 years using litter traps. Direct inputs to streams within the reserves were relatively high (550–617 g ash free dry weight (AFDW) m–2 year–1), but were lower at farmland reaches with the lowest canopy covers (83–117 gAFDW m–2 year–1). Only a minor fraction of the total allochthonous input (<10%) entered any of the study reaches laterally. The mean amounts of benthic detritus were lowest in the most open farmland reaches. Standing stocks of benthic detritus were found to be highly patchy across a large number of agricultural streams, but were consistently very low where the streamside canopy cover was below ~35%. Canopy cover should be restored along cleared agricultural streams because allochthonous detritus is a major source of food and habitat for aquatic ecosystems. Given the absence of pristine lowland streams in south-eastern Australia, those reaches with the most intact remnant overstorey canopies should be used to guide restoration.

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Riparian Vegetation Structure Influences Terrestrial Invertebrate Communities in an Agricultural Landscape

Water ◽

10.3390/w13020188 ◽

2021 ◽

Vol 13 (2) ◽

pp. 188

Author(s):

Cristina Popescu ◽

Mihaela Oprina-Pavelescu ◽

Valentin Dinu ◽

Constantin Cazacu ◽

Francis J. Burdon ◽

...

Keyword(s):

Riparian Vegetation ◽

Human Impacts ◽

Agricultural Landscapes ◽

Riparian Buffers ◽

Management Tool ◽

Potential Contribution ◽

Invertebrate Community ◽

Invertebrate Communities ◽

Terrestrial Invertebrate ◽

Invertebrate Diversity

Stream and terrestrial ecosystems are intimately connected by riparian zones that support high biodiversity but are also vulnerable to human impacts. Landscape disturbances, overgrazing, and diffuse pollution of agrochemicals threaten riparian biodiversity and the delivery of ecosystem services in agricultural landscapes. We assessed how terrestrial invertebrate communities respond to changes in riparian vegetation in Romanian agricultural catchments, with a focus on the role of forested riparian buffers. Riparian invertebrates were sampled in 10 paired sites, with each pair consisting of an unbuffered upstream reach and a downstream reach buffered with woody riparian vegetation. Our results revealed distinct invertebrate community structures in the two site types. Out of 33 invertebrate families, 13 were unique to either forested (6) or unbuffered (7) sites. Thomisidae, Clubionidae, Tetragnathidae, Curculionidae, Culicidae, and Cicadidae were associated with forested buffers, while Lycosidae, Chrysomelidae, Staphylinidae, Coccinellidae, Tettigoniidae, Formicidae, and Eutichuridae were more abundant in unbuffered sites. Despite statistically equivocal results, invertebrate diversity was generally higher in forested riparian buffers. Local riparian attributes significantly influenced patterns in invertebrate community composition. Our findings highlight the importance of local woody riparian buffers in maintaining terrestrial invertebrate diversity and their potential contribution as a multifunctional management tool in agricultural landscapes.

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Assessing the utility of sulfur isotope values for understanding mercury concentrations in water and biota from high Arctic lakes

Arctic Science ◽

10.1139/as-2018-0022 ◽

2019 ◽

Vol 5 (2) ◽

pp. 90-106 ◽

Cited By ~ 1

Author(s):

Gretchen L. Lescord ◽

Meredith G. Clayden ◽

Karen A. Kidd ◽

Jane L. Kirk ◽

Xiaowa Wang ◽

...

Keyword(s):

Food Webs ◽

Total Mercury ◽

Nitrogen Isotopes ◽

Sulfur Isotopes ◽

High Arctic ◽

Arctic Lakes ◽

Carbon And Nitrogen ◽

Resolute Bay ◽

Aquatic Food ◽

Globally Stable

Methylmercury (MeHg) biomagnifies through aquatic food webs resulting in elevated concentrations in fish globally. Stable carbon and nitrogen isotopes are frequently used to determine dietary sources of MeHg and to model its biomagnification. However, given the strong links between MeHg and sulfur cycling, we investigated whether sulfur isotopes (δ34S) would improve our understanding of MeHg concentrations ([MeHg]) in Arctic lacustrine food webs. Delta34S values and total mercury (THg) or MeHg were measured in water, sediments, and biota from six lakes near Resolute Bay, NU, Canada. In two lakes impacted by historical eutrophication, aqueous sulfate δ34S was ∼8‰ more positive than sedimentary δ34S, suggestive of bacterial sulfate reduction in the sediment. In addition, aqueous δ34S showed a significant positive relationship with aqueous [MeHg] across lakes. Within taxa across lakes, [THg] in Arctic char muscle and [MeHg] in their main prey, chironomids, were positively related to their δ34S values across lakes, but inconsistent relationships were found across entire food webs among lakes. Across lakes, nitrogen isotopes were better predictors of biotic [THg] and [MeHg] than δ34S within this dataset. Our results suggest some linkages between Hg and S biogeochemistry in high Arctic lakes, which is an important consideration given anticipated climate-mediated changes in nutrient cycling.

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Determinants of bird assemblage composition in riparian vegetation on sugarcane farms in the Queensland Wet Tropics

Pacific Conservation Biology ◽

10.1071/pc14904 ◽

2015 ◽

Vol 21 (1) ◽

pp. 60 ◽

Cited By ~ 4

Author(s):

Anita F. Keir ◽

Richard G. Pearson ◽

Robert A. Congdon

Keyword(s):

Riparian Vegetation ◽

Wildlife Conservation ◽

Agricultural Landscape ◽

Riparian Zone ◽

Riparian Forest ◽

Agricultural Landscapes ◽

Generalist Species ◽

Assemblage Composition ◽

Bird Assemblages ◽

Wet Tropics

Remnant habitat patches in agricultural landscapes can contribute substantially to wildlife conservation. Understanding the main habitat variables that influence wildlife is important if these remnants are to be appropriately managed. We investigated relationships between the bird assemblages and characteristics of remnant riparian forest at 27 sites among sugarcane fields in the Queensland Wet Tropics bioregion. Sites within the remnant riparian zone had distinctly different bird assemblages from those of the forest, but provided habitat for many forest and generalist species. Width of the riparian vegetation and distance from source forest were the most important factors in explaining the bird assemblages in these remnant ribbons of vegetation. Gradual changes in assemblage composition occurred with increasing distance from source forest, with species of rainforest and dense vegetation being replaced by species of more open habitats, although increasing distance was confounded by decreasing riparian width. Species richness increased with width of the riparian zone, with high richness at the wide sites due to a mixture of open-habitat species typical of narrower sites and rainforest species typical of sites within intact forest, as a result of the greater similarity in vegetation characteristics between wide sites and the forest proper. The results demonstrate the habitat value for birds of remnant riparian vegetation in an agricultural landscape, supporting edge and open vegetation species with even narrow widths, but requiring substantial width (>90 m) to support specialists of the closed forest, the dominant original vegetation of the area.

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Versatile mysids exploit multiple basal resources: implication of the bentho-pelagic habit in estuarine food webs

Hydrobiologia ◽

10.1007/s10750-014-2003-5 ◽

2014 ◽

Vol 743 (1) ◽

pp. 37-51 ◽

Cited By ~ 4

Author(s):

T. Ramarn ◽

V. C. Chong ◽

Y. Hanamura

Keyword(s):

Food Webs ◽

Basal Resources

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Effects of increased flooding on riparian vegetation: Field experiments simulating climate change along five European lowland streams

Global Change Biology ◽

10.1111/gcb.13687 ◽

2017 ◽

Vol 23 (8) ◽

pp. 3052-3063 ◽

Cited By ~ 18

Author(s):

Annemarie G. Garssen ◽

Annette Baattrup-Pedersen ◽

Tenna Riis ◽

Bart M. Raven ◽

Carl Christian Hoffman ◽

...

Keyword(s):

Climate Change ◽

Riparian Vegetation ◽

Field Experiments ◽

Lowland Streams

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Evaluation of Turbulence Stress on Submerged Macrophytes Growing in Lowland Streams Using H2O2 as an Indicator

10.1007/978-3-030-78420-1_7 ◽

2021 ◽

pp. 151-165

Author(s):

Takashi Asaeda ◽

M. Harun Rashid ◽

L. Vamisi Krishna ◽

M. Rahman

Keyword(s):

Submerged Macrophytes ◽

Lowland Streams

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Using Stable Carbon and Nitrogen Isotopes to Investigate the Impact of Desalination Brine Discharge on Marine Food Webs

Frontiers in Marine Science ◽

10.3389/fmars.2019.00142 ◽

2019 ◽

Vol 6 ◽

Cited By ~ 3

Author(s):

Michal Grossowicz ◽

Guy Sisma-Ventura ◽

Gideon Gal

Keyword(s):

Food Webs ◽

Nitrogen Isotopes ◽

Stable Carbon ◽

Carbon And Nitrogen Isotopes ◽

Carbon And Nitrogen ◽

Marine Food Webs ◽

Marine Food ◽

The Impact

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Effects of aquatic macrophytes on physico-chemical conditions of three contrasting lowland streams: a consequence of diffuse pollution from agriculture?

Water Science & Technology ◽

10.2166/wst.2001.0277 ◽

2001 ◽

Vol 43 (5) ◽

pp. 163-168 ◽

Cited By ~ 12

Author(s):

R. J. Wilcock ◽

J. W. Nagels

Keyword(s):

Aquatic Macrophytes ◽

Aquatic Vegetation ◽

Submerged Macrophytes ◽

Third Stream ◽

Lowland Streams ◽

Riparian Plants ◽

Agricultural Catchments ◽

Physico Chemical ◽

Photosynthetic Production ◽

Chemical Conditions

Three lowland streams in developed pasture catchments with different farming intensities exhibited contrasting summer diurnal variations in pH, DO and temperature. These are ascribed to differences in dominant aquatic vegetation and their respective effects on shade, and on photosynthetic production and respiration within each stream. The stream dominated by submerged macrophytes had the greatest amplitude swings in DO and pH, and DO levels of 86–128% saturation. Floating marginal macrophytes reduced photosynthetic inputs while providing additional organic loading for respiration, with consequent flat DO and pH curves and conditions not conducive to healthy stream ecosystems. The third stream was shaded by riparian plants, which inhibited photosynthetic effects on DO and pH so that diurnal variation was intermediate between the other two streams. The interaction between nutrients and increased insolation in agricultural catchments, in stimulating aquatic plants, needs to be better understood for managing the sustainability of stream habitats and ecosystems.

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