The Subtropical Grasslands LTAR: balancing agricultural production and conservation goals

Abstract:

Subtropical grazing lands of peninsular Florida have been shaped by a long evolutionary history of lightning ignited fire followed by flooding resulting in a vast treeless prairie region in south-central Florida. In these grassland ecosystems fire return intervals are between 1-3 years. Beginning in the 1500’s, Andalusian cattle began grazing in this region and the cattle industry began in earnest in the late 1800s/early 1900s. Today, Florida’s prairie region is largely occupied by cow/calf ranch operations and also occupies the Northern Everglades watershed where water quality/quantity issues are at the forefront of environmental concerns. Florida ranches are characterized by a gradient of management intensities, ranging from sown pastures (most intensively managed) to semi-native pastures with a mix of introduced and native grasses, and rangeland (least managed ecosystem). Located at Archbold Biological Station, MacArthur Agro-ecology Research Center, and University of Florida Range Cattle Research Center (www.maerc.org; www.rcrec-ona.ifas.ufl.edu), a primary goal of the Subtropical Grasslands US Department of Agriculture Long-term Agro-Ecosystem Research LTAR is to balance intensification of sown pastures while enhancing management of native systems in a way that maximizes other ecosystem services (regulating, supporting, cultural, biodiversity). Here, we describe our proposed experimental design to compare ecosystem delivery from conventional and aspirational management regimes in sown pastures and native systems. Aspirational management goals are to (i) maximize productivity in sown pastures with a neutral effect on other ecosystem services, and (ii) manage native systems in a way that maximizes regulating, supporting, and biodiversity ecosystem services by utilizing patch burn grazing. Ultimately, we will determine if enhanced production in sown pasture under the aspirational management system can offset any reduction in productivity in semi-native/native systems managed for services other than production. Cross-site analyses with other LTAR sites are planned to assess energy balance and gas exchange in croplands of the southeastern U.S. and to compare controlling factors and processes across humid, subtropical and sub-humid continental beef-grazing systems.