Germination after simulated rat damage in seeds of two endemic Hawaiian palm species

Abstract

Seed predation by native and alien rodents can limit plant recruitment and ultimately affect forest dynamics and composition (Campbell & Atkinson 2002, Côtéet al. 2003, Hulme 1998, Sánchez-Cordero & Martínez-Gallardo 1998). Even partial consumption of seeds by predators may affect plant community structure, though its importance is poorly understood (Steeleet al. 1993, Vallejo-Marínet al. 2006). Despite consumption of relatively large portions of seeds by herbivores, seeds can retain their ability to germinate if the embryo remains intact (Dalling & Harms 1999, Janzen 1972, Mack 1998). Germination of damaged seeds may be accelerated or prolonged (Karban & Lowenberg 1992, Koptur 1998, Vallejo-Marínet al. 2006). Damage by seed pests also facilitates ageing stress; which manifests as decreased seedling vigour, decreased seed viability, lower germination percentages and slower germination rates (Priestley 1986).

Seed predation by rodents results in directed dispersal of viable seed fragments of an endangered desert shrub

“…The ability to germinate from partially destroyed seeds has been reported for several large-seeded species (e.g., Dalling et al1997, Joshi et al 2006, Vallejo-Marín et al 2006, Pérez et al 2008, Teixeira and Barbedo 2012. This ability is likely retained because larger seeds have greater quantities of nutritional tissue, which allows them to withstand different levels of endosperm loss (Dalling et al 1997, Mack 1998.…”

Biology and Impacts of Pacific Island Invasive Species. 11.Rattus rattus,the Black Rat (Rodentia: Muridae)

“…The diet of R. rattus in the Pacific has been well studied using a variety of methods, including examination of stomach contents ( Kami 1966, Yabe 1979, Clark 1981, Sugihara 1997, Cole et al 2000, Sweetapple and Nugent 2007, Caut et al 2008a, field observations of chewed food items ( Norman 1970, Meyer and Shiels 2009, Pender et al 2013, field trials measuring food item removal ( Norman 1970, Abe 2007, Shiels and Drake 2011, captive-feeding trials (Amarasakare 1994, Williams et al 2000, Pérez et al 2008, Gregory and Macdonald 2009, Meyer and Shiels 2009, Shiels 2011, and stable isotope analysis (Harper 2006, Caut et al 2008a,b, Shiels et al 2013. As a whole, these dietary assessments confirm that R. rattus is highly omnivorous, eating a wide variety of plants, invertebrates, vertebrates, and fungi ( Figure 3).…”

“…rattus (Pérez et al 2008), and several other native trees in Hawai'i also suffer R. rattus seed predation (Shiels and Drake 2011). In a New Zealand forest, seed fragments were the dominant food item in adult R. rattus stomach contents, composing 48% of their total diet (Sweetapple and Nugent 2007), whereas in a Hawaiian forest approximately 25% of the stomach contents were seed fragments (Shiels et al 2013).…”

Dietary niche differentiation among three species of invasive rodents (Rattus rattus, R. exulans, Mus musculus)

“…Techniques commonly used to assess the diets of introduced rodents include field observations of partially consumed prey (e.g., seeds, mollusks, arthropods ;Norman 1970;McConkey et al 2003;Meyer and Shiels 2009), captive-feeding trials (Bunn and Craig 1989;Williams et al 2000;Pérez et al 2008;Shiels 2011), and stomach content analysis (Clark 1981(Clark , 1982Amarasekare 1994;Pisanu et al 2011). Additionally, the analysis of naturally-occurring stable isotope ratios (i.e., d…”