Insects mediate the effects of propagule supply and resource availability on a plant invasion.
Invasive species are a global threat to biodiversity and the functioning of natural ecosystems. Here, we report on a two-year experiment aimed at elucidating the combined and relative effects of three key controls on plant invasions: propagule supply, soil nitrogen (N) availability, and herbivory by native insects. We focus on the exotic species Lespedeza cuneata, a Rank 1 invasive species. Propagule supply and soil N-availability interacted to control the density and foliar cover of L. cuneata. In low N plots, density and foliar cover of L. cuneata were higher in the propagule addition plots than in the plots to which propagules were not added. Surprisingly, this interaction was significant only when the abundance of herbivores was experimentally reduced. This experiment provides evidence that native insect herbivores mediate the interactive effects of propagule supply and resources on invasion by a widespread invasive plant species.
Sanders
Nathan J
NJ
Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996-1610, USA. nathan.sanders@utk.edu
Weltzin
Jake F
JF
Crutsinger
Gregory M
GM
Fitzpatrick
Matthew C
MC
Nuñez
Martin A
MA
Oswalt
Christopher M
CM
Lane
Kristin E
KE
D000818:Animals; D044822:Biodiversity; D002244:Carbon / Q000378:metabolism; D017753:Ecosystem; D004777:Environment; D007313:Insecta / Q000502:physiology*; D029884:Lespedeza / Q000254:growth & development* / Q000502:physiology; D009584:Nitrogen / Q000378:metabolism; D011156:Population Density; D011157:Population Dynamics; D012987:Soil / Q000032:analysis*
D012987:Soil; D002244:Carbon; D009584:Nitrogen