Invasive alien species in protected areas: the dynamics of Pinus taeda at Rio Canoas State Park – Brazil

Abstract

Biological invasion is a growing problem, and species of the genus Pinus are known to be a problem in the forests of southern Brazil, including in conservation units. Here, we studied the ecology of Pinus taeda L. invasion in Rio Canoas State Park (PAERC) in regards to forest inventory, soil seed bank analysis, and seed rain assessment, in three distinct successional stages inside the park referred to as “Pinus invasion”, “Old Growth Vegetation”, and “Initial Vegetation”. The forest inventory of 33 (20 m × 20 m) plots found Pinus in two of the three evaluated environments. Seed rain was collected bimonthly using 33 (1 m × 1 m) seed traps for a period of 1 year. The major seed distribution periods were in April and June, confirming data found in the literature. The seed bank was analyzed in February (summer) and June (winter) of 2018. Samples were kept in a greenhouse for a period of 120 days each. Summer evaluation showed no emergence of Pinus taeda seedlings, but the winter evaluation (June) did show the emergence of seedlings. The results showed that the soil seed bank is not persistent. Accordingly, the Pinus invasion reported at PAERC requires a restoration program, as well as one that controls reinfestation.