Short‐ and long‐term effects of disturbance and propagule pressure on a biological invasion

Abstract

Summary 1.Invading species typically need to overcome multiple limiting factors simultaneously in order to become established, and understanding how such factors interact to regulate the invasion process remains a major challenge in ecology. 2. We used the invasion of marine algal communities by the seaweed Sargassum muticum as a study system to experimentally investigate the independent and interactive effects of disturbance and propagule pressure in the short term. Based on our experimental results, we parameterized an integrodifference equation model, which we used to examine how disturbances created by different benthic herbivores influence the longer term invasion success of S. muticum . 3. Our experimental results demonstrate that in this system neither disturbance nor propagule input alone was sufficient to maximize invasion success. Rather, the interaction between these processes was critical for understanding how the S. muticum invasion is regulated in the short term. 4. The model showed that both the size and spatial arrangement of herbivore disturbances had a major impact on how disturbance facilitated the invasion, by jointly determining how much space-limitation was alleviated and how readily disturbed areas could be reached by dispersing propagules. 5. Synthesis. Both the short-term experiment and the long-term model show that S. muticum invasion success is co-regulated by disturbance and propagule pressure. Our results underscore the importance of considering interactive effects when making predictions about invasion success.

Invasive species in Europe: ecology, status, and policy

“…Disturbance increases plant invasions because it leads to loss of native species that could compete with introduced non-native species, and because it increases availability of resources [58]. High propagule pressure occurs in the same regions because human activities lead to many plant introductions [59].…”

Climatic variation alters supply‐side ecology: impact of climate patterns on phytoplankton and mussel recruitment

“…Propagule (larvae, spores, seeds) inputs can be a key factor in determining community structure (Underwood and Denley 1984, Menge and Sutherland 1987, Denny and Paine 1998, Connolly and Roughgarden 1999, Sagarin et al 1999, Foster and Dickson 2004, Paine and Trimble 2004, Smith et al 2006, Britton-Simmons and Abbott 2008. For example, while the influence of high rates of recruitment on population abundance is often modified by post-recruitment processes such as species interactions and environmental stress, low recruitment rates can be an important, limiting determinant of adult abundances (Connell 1985, Gaines and Roughgarden 1985, Minchinton and Scheibling 1991, Menge 2000.…”

Manipulating the intrinsic parameters of propagule pressure: implications for bio‐invasion

“…Tests of propagule pressure effects should be conducted within the context of the biotic and abiotic conditions of the receiving community (Ruiz et v www.esajournals.org al. 2000a, Von Holle and Simberloff 2005, Thomsen et al 2006, Britton-Simmons and Abbott 2008. This is particularly important for studies of bio-invasion as greater invader establishment generally occurs with increased total propagule pressure and some form of community perturbation (Lambrinos 2006).…”