Seed dispersal effectiveness by a large‐bodied invasive species in defaunated landscapes

Abstract

Animal‐dispersed plants are increasingly reliant on effective seed dispersal provided by small‐bodied frugivores in defaunated habitats. In the Neotropical region, the non‐native wild pig (Sus scrofa) is expanding its distribution and we hypothesized that they can be a surrogate for seed dispersal services lost by defaunation. We performed a thorough analysis of their interaction patterns, interaction frequencies, seed viability, and characteristics of the seed shadows they produce. We found 15,087 intact seeds in 56% of the stomachs and 5,186 intact seeds in 90% of the scats analyzed, 95% of which were smaller than 10 mm in diameter. Wild pigs were the third most effective disperser among 21 extant frugivore species in a feeding trail experiment in terms of quantity of seeds removed. Gut retention time was 70 ± 23 hr, indicating wild pigs can promote long‐distance seed dispersal. Seed survival after seed handling and gut passage by wild pigs was positively related with seed size, but large seeds were spat out and only smaller seeds were defecated intact, for which we observed a positive or neutral effect on germination relative to manually de‐pulped seeds. Finally, deposition of seeds was four times more frequent in unsuitable than suitable sites for seedling recruitment and establishment. Seed dispersal effectiveness by wild pigs is high in terms of the quantity of seeds dispersed but variable in terms of the quality of the service provided. Our study highlights that negative and positive effects delivered by non‐native species should be examined in a case by case scenario. Abstract in Portuguese is available with online material.

Seed removal of Araucaria angustifolia by native and invasive mammals in protected areas of Atlantic Forest

“…In some landscapes, especially those where the frequency of disturbances has been changed by human activities (Badano & Cavieres 2006), exotic ecosystem engineers, such as wild pig, could eventually replace ecological functions of native ecosystem engineers that are locally extinct (see Novel Ecosystem concept in Hobbs et al 2006and Hobbs et al 2009, Pedrosa et al 2019. Thus, more studies evaluating the effects of wild pig on the final destination of seeds (i.e.…”

“…They are recognized as an important alien ecosystem engineers with high ecological plasticity, changing the soil, vegetation cover and seed bank structure (Barrios-Garcia & Ballari 2012, Cuevas et al 2012, Ickes et al 2001, Webber et al 2010, and competing with native fauna for resources (Hegel et al 2019, Sanguinetti & Kitzberger 2010. The range of the wild pig is expanding throughout tropical forests (Clout & Russell 2007, Rosa et al 2017, where they are mainly recognized as seed removers, although they may eventually also act as dispersers (Sanguinetti & Kitzberger 2010, Pedrosa et al 2019.…”

The Fate of Bryophyte Sporophytes—Phenology and Vectors of Buxbaumia viridis in the Kalkalpen National Park, Austria

“…We observed a high number of mice, which should be considered as important vectors in the medium range. The action radius of the observed birds and large mammals in our study, e.g., wild boar, is even larger [ 44 ], and these should be considered as potential vectors of Buxbaumia viridis in the long range. Furthermore, Heinken et al [ 27 ] proposed the epizoochorous dispersal of bryophyte fragments by roe deer and wild boar as an important vector for bryophytes.…”

The forgotten fauna: Native vertebrate seed predators on islands

“…In Hawaiʻi, pigs are functionally most closely related to large ground-dwelling birds, such as the extinct moa-nalo and introduced Galliformes ( Figure 5). However, unlike these taxa, pigs destroy seeds with their teeth, and may act as dispersers or seed predators depending on the traits of the seeds they consume (Beveridge, 1964;O'Connor & Kelly, 2012;Pedrosa, Bercê, Levi, Pires, & Galetti, 2019).…”

“…Understanding where animals fit on this continuum generally requires feeding trials (e.g. Pedrosa et al, 2019), but these trials are labour intensive for extant species, and are impossible for extinct species (although coprolites can give insights into the proportion of seeds destroyed or dispersed by extinct species; see Carpenter, Wood, et al, 2018). However, recent reconstructions of the ecological function of extinct species underpinned by modelling, inferences from allometric scaling and palaeoecological data demonstrate new capabilities in understanding the roles of extinct species (e.g.…”