Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA 50011;
Department of Statistics, Iowa State University, Ames, IA 50011.
Proc Natl Acad Sci U S A. 2017 Oct 17;114(42):11247-11252. doi: 10.1073/pnas.1620229114. Epub 2017 Oct 2.
Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland. In a catchment-scale experiment, we quantified the multiple effects of integrating strips of native prairie species amid corn and soybean crops, with prairie strips arranged to arrest run-off on slopes. Replacing 10% of cropland with prairie strips increased biodiversity and ecosystem services with minimal impacts on crop production. Compared with catchments containing only crops, integrating prairie strips into cropland led to greater catchment-level insect taxa richness (2.6-fold), pollinator abundance (3.5-fold), native bird species richness (2.1-fold), and abundance of bird species of greatest conservation need (2.1-fold). Use of prairie strips also reduced total water runoff from catchments by 37%, resulting in retention of 20 times more soil and 4.3 times more phosphorus. Corn and soybean yields for catchments with prairie strips decreased only by the amount of the area taken out of crop production. Social survey results indicated demand among both farming and nonfarming populations for the environmental outcomes produced by prairie strips. If federal and state policies were aligned to promote prairie strips, the practice would be applicable to 3.9 million ha of cropland in Iowa alone.
尽管美国在自然资源管理上投入了数十年的时间,但农业用地的生物多样性丧失和生态系统服务退化仍然是一个重要挑战。迄今为止,保护投资一直强调工程实践或以单一种植非本地植物为中心的植被策略,这使得本地物种在农田中基本被排除在外。在一个集水区规模的实验中,我们量化了在玉米和大豆作物中整合原生草原物种带的多种影响,这些草原带的布置是为了在斜坡上拦截径流。用草原带替代 10%的农田可以在对作物生产影响最小的情况下增加生物多样性和生态系统服务。与仅包含作物的集水区相比,将草原带整合到农田中可以使集水区层面的昆虫分类丰富度(增加 2.6 倍)、传粉者丰富度(增加 3.5 倍)、本地鸟类物种丰富度(增加 2.1 倍)和最需要保护的鸟类物种丰富度(增加 2.1 倍)增加。草原带的使用还使集水区的总径流量减少了 37%,从而保留了 20 倍以上的土壤和 4.3 倍以上的磷。有草原带的集水区的玉米和大豆产量仅减少了从作物生产中划出的面积。社会调查结果表明,农民和非农民群体都对草原带带来的环境成果有需求。如果联邦和州政策能够协同一致地推动草原带的发展,那么仅在爱荷华州就有 390 万公顷的农田可以采用这种做法。