Data from: Invasive dominance and resident diversity: unpacking the impact of plant invasion on biodiversity and ecosystem function

Plant invasions have consistently been shown to cause significant
reductions in the diversity of recipient plant communities; an effect that
can cascade through ecosystems to impact the stocks and flows of nutrients
and energy as well as the diversity of higher trophic levels. However, the
manner in which invasive plants alter ecosystem functioning and trophic
interactions is highly variable can occur through the direct effects of
the invader’s abundance and its indirect effects via changes in community
diversity. Understanding the nature of these interactions between plant
invasion, community diversity and ecosystem functioning can provide
insight for ecosystem managers. We evaluated whether plant invasion alters
the relationship between biodiversity and ecosystem function (BEF) by
comparing BEF models that either include or subtract the diversity and
function values associated with the invasive vine, Vincetoxicum rossicum.
To do this, we 1) characterize V. rossicum within the functional trait
space of the regional species pool; 2) assess how different components of
plant biodiversity vary along a V. rossicum invasion gradient; and 3)
examine how V. rossicum invasion affects BEF relationships and trophic
interactions, both at the plot-scale and incrementally along a site-level
invasion gradient. In general, we found that V. rossicum invasion was
associated with significant declines in plant community diversity across a
suite of biodiversity measures; a consequence of V. rossicum’s functional
trait structure (height and specific leaf area). We also found that V.
rossicum invasion resulted in significantly greater productivity (i.e.
dominance effects in the inclusion model), but also that the diversity of
the remaining resident community was positively associated with
productivity (i.e. niche complementarity in the subtraction model).
Further, we observed that while the relationship between flower cover and
pollinator diversity was positive for both the inclusion and subtraction
models, this relationship was stronger in the absence of V. rossicum. Our
findings suggest that while plant invasion can result in enhanced
productivity via dominance effects, this comes at the cost of significant
declines in diversity. However, it is also the case that remaining
resident diversity can exhibit positive effects on multiple functions and
support for higher trophic levels.