COS 85-2 - Agricultural land-use has long-term effects on the physical and biotic forest environment

Thursday, August 11, 2016: 1:50 PM
Palm A, Ft Lauderdale Convention Center
Marion A. Holmes and Glenn R. Matlack, Environmental and Plant Biology, Ohio University, Athens, OH

The physical and biotic environment in modern forests is potentially shaped by previous land uses such as agriculture, which alter soil structure and chemistry and deplete reservoirs of seeds, seedlings, and perennating organs. To better understand the long-term effects of agriculture, we compared successional trajectories between stands with a history of cultivation to those with a history of pasturing. We tested two hypotheses: 1) the physical environment changes though successional time to more closely resemble long-undisturbed mature forests; 2) previous cultivation and pasturing will remain distinguishable in second-growth forest, including differences in tree community composition and structure.   Forest stands were selected on abandoned pastures and cultivated fields to form a replicated chronosequence spanning 0-80 years.  Five minimally-disturbed mature stands >120 years were included as a control. Stand age and land-use history were determined using historical photographs,  surface microtopography, and soil profiles. Biotic and abiotic variables were recorded in replicated 2 meter plots. Tree community composition and structure were sampled using the point-centered quarter method. 


Environmental characteristics changed through successional time and displayed differences between land-use histories. Soil pH decreased overall, but remained higher on cultivated sites. Microtopographic variation, litter cover, and canopy cover increased through time, but showed little difference with agricultural history. Tree density decreased; tree community composition both changed through successional time and differed between land-use histories. Early successional tree species decreased in size and density, and were not present in the oldest forest class. Mature forest species were not present until several decades after abandonment. Thus, successional trajectories in the physical and structural forest environment differ between land use histories, apparently driven by contrasting development of the tree community on previously tilled and pastured land.