Invasive pines in Argentinian grasslands: lessons from control operations

Abstract

Biological invasions are one of the most important challenges for protected areas around the world, both because of the seriousness of their effectsand because of the costs and difficulties associated with their control. Some features of the biology of invasive species, such as growth rate and reproduction, can be particularly important when organizing controlactions. Moreover, the control actions themselves can be used to gather information to adjust their effectiveness. In mountain habitats, understanding how topography influences recruitment, growth and reproductioncan provide key information for optimizing prevention and control efforts. In this article, we used data from 9093 cutted invasive Aleppo pines (Pinushalepensis) obtained from management operations in a natural reserve in the Southern Argentinian Pampas. Our results reveal variations in the growth rate, cone production and seed release in response to topography. The specimens that grow at higher altitudes exhibit larger diameters than those of equal age growing at lower altitudes. A greater frequency of individuals with thick trunks in the mountains tops has operative implications when selecting cutting tools and calculating effort and frequency of tools maintenance. We also found that trees located in higher environments start releasing seeds at a younger age. This could mean potential higher population growth rates in this habitatand as a consequence in greater risk of long-distance dispersal, highlighting the need to prioritize control operations in higher areas and to increase thefrequency between successive controls to avoid the release of seeds that can be dispersed over long distances.