ABSTRACT

Riparian plants provide an important source of energy for freshwater food webs through inputs of leaf litter. Planting riparian buffers with mixed species could enhance the detrital resource supply for invertebrates through varied leaf breakdown rates. To quantify leaf breakdown rates and invertebrate colonisation, we used leaves from eleven grass, shrub and tree species common along agricultural waterways in New Zealand. Breakdown of leaves immersed in a spring-fed stream differed significantly among species, being fastest for pasture grass (k = 0.0458 day⁻¹) followed by broadleaf, pittosporum, willow, toetoe, poplar, gorse, Carex, eucalyptus, flax, and slowest for cabbage tree leaves (k = 0.0099 day⁻¹). Invertebrate community composition did not differ between leaf species, but consumers were extremely abundant on some leaves (e.g. 51–83 Potamopyrgus snails g⁻¹ pasture grass), indicating coarse detrital resources were in high demand for food or habitat. These breakdown rates could inform selection of riparian plant combinations that will enhance food availability for stream communities, especially continuity of supply, thereby contributing to waterway restoration.

摘要

河岸植物通过落叶的输入为淡水食物网提供重要的能量来源。种植混合物种的河岸缓冲区可以通过不同的叶片分解率增加无脊椎动物的碎屑资源供应。为了量化叶子分解率和无脊椎动物的定殖，我们使用了新西兰农业水道沿线常见的 11 种草、灌木和树种的叶子。浸泡在泉水溪流中的树叶分解在不同物种之间存在显着差异，牧草最快（k  = 0.0458 天^-1），其次是阔叶草、海桐属、柳树、趾趾草、杨树、金雀花、苔草、桉树、亚麻，最慢对于卷心菜树叶 ( k  = 0.0099 day ⁻¹). 无脊椎动物群落组成在叶种之间没有差异，但某些叶的消费者非常丰富（例如 51-83 Potamopyrgus蜗牛 g ^-1牧草），表明粗碎屑资源对食物或栖息地的需求很高。这些分解率可以为河岸植物组合的选择提供信息，这些植物组合将提高河流社区的食物供应，特别是供应的连续性，从而有助于水道恢复。