Species Diversity and Invasion Resistance in a Marine Ecosystem

Abstract

Theory predicts that systems that are more diverse should be more resistant to exotic species, but experimental tests are needed to verify this. In experimental communities of sessile marine invertebrates, increased species richness significantly decreased invasion success, apparently because species-rich communities more completely and efficiently used available space, the limiting resource in this system. Declining biodiversity thus facilitates invasion in this system, potentially accelerating the loss of biodiversity and the homogenization of the world's biota.

Species diversity defends against the invasion of Nile tilapia (Oreochromis niloticus)

“…Spatial scales can also affect invaders through competition, predation, and pathogen and disease resistance (Kenney et al, 2002;Davies et al, 2010). Most experimental studies, which are necessarily conducted on small scales, support the idea that species richness decreases invasion success (Knops et al, 1999;Stachowicz et al, 1999Stachowicz et al, , 2006Levine, 2000;Kenney et al, 2002). However, there is also convincing evidence that the relationship between the diversity of native and invading species is positive when measured on large spatial scales (Stohlgren et al, 1999;Levine et al, 1999;Levine, 2000;Richardson et al, 2005;Davies et al, 2005Davies et al, , 2010.…”

“…Native communities prevent invasions through a variety of mechanisms, and these mechanisms are referred to as "biotic resistance" (Elton, 1958). The theory of biotic resistance predicts that communities with greater diversity will inhibit invasive species, which is supported by both theory and experimental studies (Elton, 1958;Stachowicz et al, 1999;Kennedy et al, 2002;Tilman, 2004;Davies et al, 2005Davies et al, , 2010Carey and Wahl, 2010). In many studies, biotic resistance refers to the ability of a natural community to resist the establishment of invaders (Stohlgren et al, 1999;Levine, 2000;Meador et al, 2003;Davies et al, 2005;Davies et al, 2010;Kimbro et al, 2013).…”

“…Most studies that support this idea are observational studies, and most have investigated the relationship between populations of exotic fish and native diversity (Stohlgren et al, 1999;Levine et al, 1999;Levine, 2000;Davies et al, 2005Davies et al, , 2010. Furthermore, most studies supporting biodiversity resistance have examined the relationship between exotic biomass and native diversity (Knops et al, 1999;Stachowicz et al, 1999Stachowicz et al, , 2002Stachowicz et al, , 2006Levine, 2000;Kenney et al, 2002). However, previous studies have focused on how native communities have affected the successful establishment of invaders rather than how native communities have affected the persistence of invaders after their establishment (Levine et al, 1999;Kimbro et al, 2013), despite the fact that the principles of biodiversity resistance also apply to established invaders.…”

“…Instead, the structure of native communities may be important. The relationship between the structure of native communities and invasion success has been discussed in many studies (Elton, 1958;Stachowicz et al, 1999Stachowicz et al, , 2002Stohlgren et al, 1999;Levine et al 1999;Levine, 2000;Kenney et al, 2002;Richardson et al, 2005;Davies et al, 2005Davies et al, , 2010Kimbro et al, 2013). However, the relative contribution of resident diversity to invasion resistance varies across different spatial scales (Kenney et al, 2002;Davies et al, 2010).…”

“…Studies suggest that species loss on small scales may reduce invasion resistance (Elton, 1958;Stachowicz et al, 1999Stachowicz et al, , 2002Levine, 2000;Kenney et al, 2002;Davies et al, 2005Davies et al, , 2010Kimbro et al, 2013). In addition, resources are used more completely in diverse communities on small spatial scales (Kenney et al, 2002;Tilman, 2004;Stachowicz et al, 1999Stachowicz et al, , 2006, and native species are more likely to resist invasion because they are likely to occupy similar niches (Davies et al, 2010). Spatial scales can also affect invaders through competition, predation, and pathogen and disease resistance (Kenney et al, 2002;Davies et al, 2010).…”