title: The use of wooden sticks to assess stream ecosystem functioning: comparison with leaf breakdown rates.
abstract: Breakdown of organic matter is a key process in streams and rivers, and thus, it has potential to assess functional impairment of river ecosystems. Because the litter-bag method commonly used to measure leaf breakdown is time consuming and expensive, several authors proposed to measure breakdown of wooden sticks instead. Nevertheless, currently there is little information on the performance of wooden sticks versus that of leaves. We compared the breakdown of tongue depressors made of untreated poplar wood, to that of six common leaf species in two large streams in the Basque Country (northern Spain), one polluted and the other unpolluted. Breakdown rates ranged from 0.0011 to 0.0120 day(-1), and were significantly lower in the polluted stream. Wooden sticks performed very similarly to leaves, but were less affected by flood-induced physical abrasion. The ranking of the materials according to their breakdown rate was consistent, irrespective of the stream. The experiments with leaves were 10 times more costly for breakdown rate, 4 times if we include the rest of the variables measured. Therefore wooden sticks offer a promising tool to assess river ecosystem functioning, although more research is necessary to define the thresholds for ecosystem functional impairment.
authors.affiliation: Faculty of Science and Technology, The University of the Basque Country, PO Box 644, 48080 Bilbao, Spain. maite.arroita@ehu.es
authors.forename: Maite
authors.initials: M
authors.lastname: Arroita
authors.forename: Ibon
authors.initials: I
authors.lastname: Aristi
authors.forename: Lorea
authors.initials: L
authors.lastname: Flores
authors.forename: Aitor
authors.initials: A
authors.lastname: Larrañaga
authors.forename: Joserra
authors.initials: J
authors.lastname: Díez
authors.forename: Juanita
authors.initials: J
authors.lastname: Mora
authors.forename: Anna M
authors.initials: AM
authors.lastname: Romaní
authors.forename: Arturo
authors.initials: A
authors.lastname: Elosegi
mesh_terms: D000818:Animals; D018533:Biomass; D017753:Ecosystem; D004784:Environmental Monitoring / Q000191:economics / Q000379:methods*; D005658:Fungi / Q000502:physiology; D007448:Invertebrates / Q000145:classification; D018515:Plant Leaves / Q000378:metabolism*; D012098:Reproduction; D045483:Rivers / Q000737:chemistry*; D013030:Spain; D013045:Species Specificity; D013997:Time Factors; D014197:Trees / Q000378:metabolism; D060753:Water Quality; D014934:Wood / Q000378:metabolism*