Comparison of leaf decomposition and macroinvertebrate colonization between exotic and native trees in a freshwater ecosystem

• Published in: Ecological research Vol. 25; no. 3; pp. 647 - 653
• Main Authors: Alonso, A, Gonzalez-Munoz, N, Castro-Diez, P
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01.05.2010; Blackwell Publishing Ltd
• Subjects: Ailanthus altissima; alien plant invasions; Aquatic ecosystems; Behavioral Sciences; Biomedical and Life Sciences; breakdown; Colonization; communities; Community; Community structure; Comparative studies; Decay; Decomposition; Detritus; Ecology; Ecosystem studies; Energy; Evolutionary Biology; Feeds; Forestry; Fraxinus; Fraxinus angustifolia; Freshwater ecology; Freshwater ecosystems; habitats; Indigenous species; Introduced species; Invasive plants; Invasive species; invertebrates; Leaf litter; Leaf litter decay; Leaves; Life Sciences; Lignin; Litter; litter decomposition; Macroinvertebrates; Native species; Nitrogen; Nutrient cycles; Organic matter; Original Article; Particulate organic matter; Plant Sciences; Plant species; rates; riparian vegetation; Robinia; Robinia pseudoacacia; shredders; streams; Trees; Ulmus minor; Zoology; Leaf litter decay; Lignin; Invasive species; Nitrogen; Community
• ISSN: 0912-3814; 1440-1703
• DOI: 10.1007/s11284-010-0698-y

One of the most important sources of energy in aquatic ecosystems is the allochthonous input of detritus. Replacement of native tree species by exotic ones affects the quality of detritus entering freshwater ecosystems. This replacement can alter nutrient cycles and community structure in aquatic ecosystems. The aims of our study were (1) to compare leaf litter decomposition of two widely distributed exotic species ( Ailanthus altissima and Robinia pseudoacacia ) with the native species they coexist with ( Ulmus minor and Fraxinus angustifolia ), and (2) to compare macroinvertebrate colonization among litters of the invasive and native species. Litter bags of the four tree species were placed in the water and collected every 2, 25, 39, 71, and 95 days in a lentic ecosystem. Additionally, the macroinvertebrate community on litter bags was monitored after 25, 39, and 95 days. Several leaf chemistry traits were measured at the beginning (% lignin; lignin:N, C:N, LMA) and during the study (leaf total nitrogen). We detected variable rates of decomposition among species ( k values of 0.009, 0.008, 0.008, and 0.005 for F. angustifolia , U. minor , A. altissima and R. pseudoacacia , respectively), but we did not detect an effect of litter source (from native/exotic). In spite of its low decay, the highest leaf nitrogen was found in R. pseudoacacia litter. Macroinvertebrate communities colonizing litter bags were similar across species. Most of them were collectors (i.e., they feed on fine particulate organic matter), suggesting that leaf material of either invasive or native trees was used as substrate both for the animals and for the organic matter they feed on. Our results suggest that the replacement of the native Fraxinus by Robinia would imply a reduction in the rate of leaf processing and also a slower release of leaf nitrogen to water.