Wood decay rates and macroinvertebrate community structure along contrasting human pressure gradients ( Waikato, New Zealand)

作者：Collier K J^*

来源：New Zealand Journal of Marine and Freshwater Research, 2014, 48(1): 97-111.

DOI：10.1080/00288330.2013.847470

• functional indicator
• organic matter breakdown
• urban stream
• large river
• agriculture
• abstraction
• benthos

Mass loss rates of wooden sticks (Betula platyphylla Sukaczev) and macroinvertebrate community composition were measured in the Waikato Region of northern New Zealand at 53 running water sites draining native forest catchments (reference), or characterised by urban, industrial, agroforestry or hydrological stressors. Overall wood substrates retained 80% of initial dry mass over 2-3 month incubation periods, equating to average daily decay coefficients (k(d)) of 0.0027 or 0.0002 when adjusted for degree days (k(dd)). There were no statistically significant differences in decay rates between stressor types and native forest reference sites. In contrast, macroinvertebrate richness and compositional metrics varied significantly from reference conditions for several stressor types. Wood decay rates were weakly related to macroinvertebrate community composition, while k(dd) was weakly but significantly related to % worms%26apos;, %EPT* abundance and Quantitative Macroinvertebrate Community Index. The results indicate weak correspondence between macroinvertebrate indicators and wood decay rates, with spatial and temporal factors potentially masking stressor responses. Before wood decay can be widely used as an indicator of lotic ecosystem health there needs to be an improved understanding of environmental factors affecting breakdown rates.

• 出版日期2014-1-2