Pitch pine ( Pinus rigida Mill.) invasion of Cape Cod pond shores alters abiotic environment and inhibits indigenous herbaceous species

• Published in: Biological conservation 2004-04, Vol.116 (2), p.181-189
• Main Authors: Craine, Stephen I, Orians, Colin M
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Coastal plain pond shores; Conservation, protection and management of environment and wildlife; Disturbance regime; Fundamental and applied biological sciences. Psychology; Mechanisms of competition; Native invasives; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Pinus rigida
• ISSN: 0006-3207; 1873-2917
• DOI: 10.1016/S0006-3207(03)00188-5

Invasion by pitch pine ( Pinus rigida Mill.) on coastal plain pond shores may have direct impacts on the herbaceous community, or may merely indicate changes in hydroperiod, which are the actual cause of community change. We compared abiotic conditions and community composition of sites that had been invaded by P. rigida and those that had not on two Cape Cod ponds. Soil under living pines had lower pH and water content, reduced net nitrification, and increased rates of ammonification. Dense stands of pine saplings reduced PAR penetrance by 94% and excluded virtually all herbaceous species. To determine if pines alone can change community composition, we imposed artificial shade and added pine needle litter to experimental plots. In the course of one growing season, both litter and shade significantly reduced the frequency of herbs in the herbaceous zone of the pond shore. Litter had the greater effect (significant for six of seven taxa), while shade reduced the frequencies of three taxa significantly.