The Structure of Riparian Vegetation in Agricultural Landscapes Influences Spider Communities and Aquatic-Terrestrial Linkages

Abstract

Riparian habitats are important ecotones connecting aquatic and terrestrial ecosystems, but are often highly degraded by human activities. Riparian buffers might help support impacted riparian communities, and improve trophic connectivity. We sampled spider communities from riparian habitats in an agricultural catchment, and analyzed their polyunsaturated fatty acid (PUFA) content to quantify trophic connectivity. Specific PUFAs are exclusively produced by stream algae, and thus are used to track uptake of aquatic resources by terrestrial consumers. Riparian spiders were collected from 10 site pairs situated along agricultural streams, and from five forest sites (25 sites total). Each agricultural site pair comprised an unshaded site with predominantly herbaceous vegetation cover, and a second with a woody riparian buffer. Spider communities differed between site types, with web-building spiders dominating woody buffered sites and free-living spiders associated with more open habitats. PUFA concentrations were greatest overall in free-living spiders, but there was also evidence for increased PUFA uptake by some spider groups when a woody riparian buffer was present. Our results reveal the different roles of open and wooded riparian habitats in supporting terrestrial consumers and aquatic-terrestrial connectivity, and highlight the value of incorporating patches of woody vegetation within riparian networks in highly modified landscapes.

Keywords

ecotone; polyunsaturated fatty acids; trophic connectivity; agriculture; spiders; riparian buffer

Published in

Water
2020, volume: 12, number: 10, article number: 2855
Publisher: MDPI

SLU Authors

• Ramberg, Ellinor

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Burdon, Francis

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Sargac, Jasmina

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Lau, Danny C P

  • Umeå University

• Johnson, Richard

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Mckie, Brendan

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology
Oceanography, Hydrology, Water Resources

Publication identifier

• DOI: https://doi.org/10.3390/w12102855

Permanent link to this page (URI)

https://res.slu.se/id/publ/109097