Role of competition in restoring resource poor arid systems dominated by invasive grasses

Abstract

a b s t r a c tUnderstanding the role competition intensity and importance play in directing vegetation dynamics is central to developing restoration strategies, especially in resource poor environments. We hypothesized 1) competition would be intense among invasive and native species, but 2) competition would be unimportant in explaining variation in target plant biomass and survivorship relative to other factors driving these variables. We performed a two year addition series field experiment to quantify competition intensity and importance. Densities of two invasive (cheatgrass and medusahead) and two native (Sandberg's bluegrass and bluebunch wheatgrass) species were arranged in monocultures and mixtures of two, three and four species, producing varying total densities and species proportions. Multiple linear regression models predicting individual plant biomass and survivorship were developed. Based on biomass, competition intensity coefficients ranged from À0.38 to 0.63 with R 2 < 0.06. All survivorship data produced poor fitting regression models (R 2 < 0.05). Our results suggest neither competition intensity nor importance influenced plant dominance in resource poor environments during the two years of establishment. Land managers may be more successful at restoration of resource poor ecosystems by overcoming abiotic barriers to plant establishment rather than focusing on planteplant interactions.

Patterns of plant community assembly in invaded and non‐invaded communities along a natural environmental gradient

“…However, invasive plant species may also affect native assemblages in more subtle and indirect ways, leading to changes in community structure and assembly by disrupting some or all of the key processes that contribute to determine the pool of plant species present (Dostal ; Mangla et al. ).…”

“…In terms of the impacts of invasive plant species on native plant communities, most of the focus has been on understanding how native species richness and diversity are affected (Gaertner et al 2009;Santoro et al 2011). However, invasive plant species may also affect native assemblages in more subtle and indirect ways, leading to changes in community structure and assembly by disrupting some or all of the key processes that contribute to determine the pool of plant species present (Dostal 2011;Mangla et al 2011).…”

Competition from Bromus tectorum removes differences between perennial grasses in N capture and conservation strategies

“…It is also important to recognize that numerous plant traits determine how seedlings respond to the suite of abiotic and biotic stressors influencing plant recruitment and survival and that different traits may be important for determining survival across life stages (Larson et al 2015). Although our study did not investigate the relative importance of traits influencing seedling recruitment or manipulate other abiotic stressors, such as drought, that ultimately may influence survival (Mangla et al 2011), our results suggest nutrient budget-related traits may contribute to the higher establishment and persistence of A. desertorum seedlings in the field when competitive pressure is low. However, for the plant developmental stages examined in this study, these same traits do not appear to increase the ability of A. desertorum to resist or inhibit the growth of B. tectorum, even under augmented soil N availability.…”

Biological soil crusts increase stability and invasion resistance of desert revegetation communities in northern China

“…2a, b, c and d). Many studies have shown that exotic plants have a better ability to use resources, thus inhibiting the growth of native plants (Flory and Clay 2010, Mangla et al 2011, Larios and Suding 2015.…”