Global and local forces for landscape perennialization.
Practices for farm production often focus on mitigating negative consequences of production of crops – particularly annuals like corn, cereals, and oilseeds – or concentrated livestock feeding operations. Recent studies have revealed rapid conversion of perennial cover to annual crops across some of North America’s most-intensive farmlands. While perennial cover like woodlands, grasslands, pasture, and hay are valued for the many landscape services they provide, they are vulnerable to conversion to other cover types under drivers of landscape change. Changes within farm operations constitute nuances rather than new land uses, yet landscape composition effects can be substantial when habitat, biodiversity, soil and water quality, carbon sequestration, and aesthetics are considered. As the farm landscape becomes increasingly dominated by annual crop vegetation, the drivers behind land cover types and management deserve critical examination.
This paper reviews some recent studies on farm landscape composition and management in central Canada and the United States. It identifies some of the trajectories and magnitudes of landscape changes. To consider forces both speculative examination of policies (like the USA’s renewable fuel standards) and direct information from farmer interviews help to identify motivations for changes in perennial or annual proportions of farm landscapes. Forces for and against annual and perennial cover are examined to seek to understand how global and local drivers combine. Recognizing that vegetation types are nearly perfect complements – that what is not annual must be perennial and vice-versa (with few exceptions) – the drivers are described in terms of how they affect landscape perennialism. The paper concludes with forces that increase perennialization and both existing or prospective pathways to improve the balance among annual and perennial vegetation.