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

Abstract

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.

The list of vascular plants for the city of Toronto

“…A list of species compiled through the Cadotte lab research within and around the city of Toronto (e.g. Arnillas & Cadotte, 2019; Livingstone, Isaac, & Cadotte, 2020).…”

The application of selected invasion frameworks to urban ecosystems

“…Having successfully overcome these barriers, V. rossicum negatively impacts native biodiversity -it reduces the diversity of plant and other trophic levels by excluding species with certain traits (DiTommaso et al 2005;Ernst and Cappuccino 2005;Sodhi et al 2019;Livingstone et al 2020). It produces chemicals (Douglass et al 2009) which can inhibit growth of other plants (allelopathy), alter soil biota, and make foliage unpalatable to native herbivores.…”

An experimental application of Hypena opulenta as a biocontrol agent for the invasive vine Vincetoxicum rossicum

“…Introduced invasive plants can spread rapidly through ecosystems, and in extreme cases result in near monocultures that cause local extirpations of native species and disrupt ecological functioning (Vilà & Hulme, 2017; Livingstone, Isaac, & Cadotte, in press). In these extreme cases, the effort and cost of chemical or physical control can preclude most viable management options (Culliney, 2005; Rejmánek & Pitcairn, 2002).…”

“…The extremely problematic invasive vine, Vincetoxicum rossicum (Kleopow) Borhidi (Apocynaceae), commonly known as pale swallow‐wort or ‘dog‐strangling vine’, has spread aggressively through its invaded range of eastern North America, following its introduction in the late 1800s. With the spread and apparent impact of V. rossicum , understanding its distribution and ecology (Averill, DiTommaso, Mohler, & Milbrath, 2011; DiTommaso, Lawlor, & Darbyshire, 2005; Milbrath, Davis, & Biazzo, 2017; Miller & Kricsfalusy, 2007), the mechanisms driving its invasion (Bongard, Butler, & Fulthorpe, 2013; Cappuccino, 2004), its impact on ecosystems (Ernst & Cappuccino, 2005; Bugiel, Livingstone, Isaac, Fulthorpe, & Martin, 2018; Livingstone et al., in press) and the effectiveness of physical and chemical control (Averill et al., 2011) have all been important research priorities. V. rossicum is a perennial vine.…”

“…The input of these allelochemicals by V. rossicum has been shown to alter soil microbial communities (Douglass, Weston, & Wolfe, 2011; Thompson, Bell, & Kao‐Kniffin, 2018); an effect that has been shown in other cases to hinder the growth and establishment of native plants (Schultheis & MacGuigan, 2018). V. rossicum ’s impact also cascades through local ecosystems by outcompeting native plant species, which in turn limits resources for invertebrate communities and disrupts specialized plant–invertebrate interactions (Livingstone et al., in press).…”