Similar biotic factors affect early establishment and abundance of an invasive plant species across spatial scales

Abstract

Research in community invasibiliy has focused on biotic and abiotic factors that influence the establishment of invasive species and whether such factors vary with spatial scale. Here, we investigate the role of both biotic and abiotic factors associated with the initial establishment of Lespedeza cuneata (L. cuneata) and its abundance at three spatial scales: neighborhoods (9-m 2 plots), communities (50-m 2 transect) and old fields (5,000-70,000 m 2 ). We asked:(1) Do resource availability and community structure affect the establishment of L. cuneata?, and (2) Are resource availability and community structure associated with patterns of L. cuneata abundance from neighborhood scales to old-field scales? To investigate the first question, we manipulated soil nitrogen (N) availability at three levels in an existing old-field community and tracked emergence and persistence of L. cuneata seedlings, as well as total plant biomass of the community, availability of light, and soil moisture content. To address the second question, we performed surveys in which we estimated L. cuneata foliar cover at community scales (50-m 2 belt transects) and old-field scales (total area of 28 ha), and assessed the same biotic and abiotic variables as in the field experiment. The experiment revealed that establishment and persistence by L. cuneata seedlings were 159 and 59 lower in N-added plots than in N-reduced plots. Total plant community biomass was 30% greater in N-added plots than in N-reduced plots. Conversely, light and soil moisture were 60 and 20% lower in N-added plots than in N-reduced plots. Surveys of old fields indicated that community biomass was positively associated with L. cuneata cover at old-field scales likely resulting from greater soil N input from nitrogen fixation in fields with greater L. cuneata cover. In sum, these results indicate that biotic factors associated with establishment of a Rank 1 invasive plant species at the community scale are also related to its distribution at the old-field scale, but the direction of such associations changed across scales.

Plant genotype, nutrients, and G × E interactions structure floral visitor communities

“…We added fertilizer as dry, slow-release pellets (nitrogen was added in the form of urea, N 2 H 4 CO, and phosphorus was added as triple super phosphate, P 2 O 5 ) which released nitrogen and phosphorus into the soil during rainfall events. These levels of enrichment have been shown to double nutrient availability in similar systems (Goldberg andMiller 1990, Sanders et al 2007) and are comparable to several local oldfield studies manipulating nutrients to examine effects on plant community dynamics (Sanders et al 2007, Blue et al 2011, Souza et al 2011a, as well as other studies examining nutrient enrichment effects on floral traits and pollinators (e.g., Campbell and Halama 1993, Asikainen and Mutikainen 2005, Munoz et al 2005, Burkle and Irwin 2009a, Burkle and Irwin 2010. We crossed Solidago altissima genotype identity and genotypic diversity with these nutrient treatments such that there were two monoculture plots of each v www.esajournals.org genotype for each nutrient treatment and three genotype mixture plots for each nutrient treatment.…”

Short-term Intensive Sustainable Restoration of Grasslands and Prairies Invaded with High Densities of Nitrogen-fixing Weeds: A Test with the Invasive Plant Lespedeza Cuneata

“… Lespedeza (L.) Cuneata is a long-lived perennial legume that has become a pervasive problem in old fields and prairies throughout parts of the United States [1][2][3][4][5][6]. For example, areas invaded by L. cuneate have lower plant and animal diversity than areas dominated by native grasses and forbs [5,7].…”

“…For example, the application of ammonium nitrate to provide nitrogen (N) has been shown to lower the competitive advantage of L. Cuneata by significantly reducing cover, stem density, and biomass [2,12]. Nitrogen applications have also been shown to have a detrimental effect on legume nodule formation and subsequent nitrogen uptake, as well as compensate for the negative effects of the allelopathic chemicals released by the plant [7,12].…”

“…Nitrogen applications have also been shown to have a detrimental effect on legume nodule formation and subsequent nitrogen uptake, as well as compensate for the negative effects of the allelopathic chemicals released by the plant [7,12]. Therefore, adding N to old fields and reclaimed prairies that typically have poor soil fertility may help native species compete with L. Cuneata [2,12,14,15]. However, a few experiments where N has been applied, N was applied at very high concentrations [2,12,14,16,17], which is not cost effective or environmentally sustainable.…”

“…Therefore, adding N to old fields and reclaimed prairies that typically have poor soil fertility may help native species compete with L. Cuneata [2,12,14,15]. However, a few experiments where N has been applied, N was applied at very high concentrations [2,12,14,16,17], which is not cost effective or environmentally sustainable. Current tall grass management strategies, using prescribed fire and fuel management to manage natural resources, have been successful in reducing and maintaininga low abundance of woody growth, but have not been successful in reducing L. Cuneata dominance [13,18,19].…”