National Institute of Water and Atmospheric Research (NIWA), P.O. Box 11-115, Hillcrest, Hamilton, New Zealand 3216.
Ecol Appl. 2011 Mar;21(2):416-26. doi: 10.1890/09-1845.1.
The contributions of biodiversity to ecosystem functioning are increasingly recognized by ecologists, with biodiversity loss considered a significant threat to the maintenance of life-supporting ecosystem goods and services. Although ecologists have increased the amount of realism in biodiversity-ecosystem functioning (BEF) experiments, effects on functioning are rarely investigated in the field in conjunction with disturbances that affect biodiversity. Here, effects on functioning were investigated in situ following experimental disturbance of a realistic type and magnitude. Experimental deposits of terrigenous sediment (5 mm thickness) were applied at three intertidal sites in Whangapoua Harbour (Coromandel Peninsula, New Zealand), where soil erosion associated with logging is a serious problem. Experimental disturbance by terrigenous sediment impacted macrofaunal abundance and community composition (suspension and deposit feeders), and there were coincident shifts in ecosystem functioning at all three sites. Relative to controls, sediment-treated plots had higher rates of ammonium efflux (despite 50% fewer macrofaunal individuals) and lower rates of gross primary production and photosynthetic efficiency (despite similar sediment chlorophyll a concentrations). Judging from nutrient ratios in sediment pore water, microphyte primary producers living on the sediment surface in control plots were likely nitrogen limited (the normal situation for marine waters), whereas microphytes in sediment-treated plots were likely phosphate limited. Gross primary production and photosynthetic efficiency were significantly and positively correlated with ammonium uptake in control plots (r2 = 0.463 and 0.856, respectively) but not in treated plots (P > 0.05, r2 < 0.3). We suggest that the higher content of charged particles (clay) in the experimental deposits bound up phosphate, limiting its bio-availability, and shifted functional relationships between sandflat macrofauna and sediment primary productivity.
生物多样性对生态系统功能的贡献越来越被生态学家所认识，生物多样性丧失被认为是维持生命支持的生态系统商品和服务的重大威胁。尽管生态学家已经在生物多样性-生态系统功能（BEF）实验中增加了现实性，但很少有研究结合影响生物多样性的干扰因素在野外调查这些实验对功能的影响。在这里，我们在进行了现实类型和规模的实验干扰后，对功能进行了现场调查。在新西兰科罗曼德尔半岛旺加波阿港的三个潮间带地点，实验性地沉积了 5 毫米厚的陆源沉积物，在那里，与伐木有关的土壤侵蚀是一个严重的问题。陆源沉积物的实验性干扰影响了大型动物的丰度和群落组成（悬浮和沉积物食者），并且在所有三个地点都发生了生态系统功能的协同变化。与对照相比，沉积物处理的斑块有更高的氨通量（尽管大型动物个体减少了 50%）和更低的总初级生产力和光合效率（尽管沉积物叶绿素 a 浓度相似）。从沉积物孔隙水中的养分比值来看，在对照斑块中生活在沉积物表面的微藻初级生产者可能受到氮限制（海洋水域的正常情况），而在沉积物处理的斑块中，微藻可能受到磷限制。在对照斑块中，总初级生产力和光合效率与氨吸收呈显著正相关（r2 = 0.463 和 0.856），但在处理斑块中则没有（P > 0.05，r2 < 0.3）。我们认为，实验沉积物中带电荷的颗粒（粘土）含量较高，束缚了磷酸盐，限制了其生物可利用性，并改变了砂质滩涂大型动物和沉积物初级生产力之间的功能关系。
