Effects of great bustard (Otis tarda) gut passage on black nightshade (Solanumnigrum) seed germination

Abstract

Effects of great bustard (Otis tarda) gut passage on black nightshade (Solanum nigrum) seed germinationLink to this article: http://journals.cambridge.org/abstract_S0960258514000178How to cite this article: C. Bravo, S. Velilla, L.M. Bautista and B. Peco (2014). Effects of great bustard (Otis tarda) gut passage on black nightshade (Solanum nigrum) seed germination. AbstractBirds are important seed dispersers for fleshy fruits through their transportation of ingested seeds. The seeds of many species germinate faster and in greater proportions after passing through a digestive tract, although the effects of this passage vary amongst bird and plant species. Many factors determine the germination success of ingested seeds, such as seed scarification during the digestion process, the fertilizing effect of droppings and the removal of pulp surrounding the seeds. In central Spain, the great bustard (Otis tarda) may act as a disperser of European black nightshade (Solanum nigrum). We analysed the germination success of ingested and non-ingested S. nigrum seeds. The fertilizing effect of bustard droppings and the disinhibition effect of the removal of Solanum pulp on final germination percentage, germination speed and viability were also assessed. Although ingested seeds germinated faster than non-ingested seeds, the former showed a lower germination percentage than the latter: 80 -87% versus 99%. Droppings and fruit pulp showed no effect on germination enhancement, except in one aspect: the germination speed of non-ingested seeds decreased when they were sprayed with a fruit extract. We confirm that seeds ingested by great bustards had lower germination success than non-ingested seeds. Although seed ingestion by great bustards reduced seedling emergence, the number of emerged seedlings was still quite large. Thus, great bustards may play a role as a S. nigrum seed dispersal vector.

A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae)

“…Tamboia et al 1996) with native bird and mammal frugivores (quail, American robins and deer mice). Bravo et al (2014) record great bustards as frugivores and seed dispersers for S. nigrum in central Spain and Barnea et al (1990) record blackbirds and bulbuls as frugivores of both S. nigrum and S. villosum (as S. luteum ) in Israel. Green fruits are expected to be more attractive to mammals, but Tamboia et al (1996) found that both birds and mammals preferred the purple berries of S. americanum to the green berries of S. sarrachoides (probably = S. nitidibaccatum , no vouchers cited).…”

“…The suite of characters expected to be attractive to mammals such as green colour, odour and abscission shortly after ripening are all found in some of the Old World morelloids such as S. tarderemotum and suggests that mammals may be important fruit dispersers for some of these species as well. Only a few ecological studies have been done on the Old World species of morelloids in their native habitats (but see Barnea et al 1990; Bravo et al 2014), although there are many anecdotal references to their dispersal by birds. The ecological interactions are likely to be similar to those observed in North America.…”

“…Barnea et al (1990) suggest this is due to the more arid habitats in which S. villosum grows, where bird defecation around shrubs would enhance survival of seedlings. Bravo et al (2014) showed that germination rates for S. nigrum were lower after ingestion by great bustards, but still concluded that the birds were likely to be efficient seed dispersal agents.…”

Does the passage of seeds through frugivore gut affect their storage: A case study on the endangered plant Euryodendron excelsum

“…Similar results on fresh seeds were found by Cosyns et al 17 who studied the effect of passage through the gastrointestinal tract on the seed germination of 19 plant species that occur in semi-natural grassland communities in Western Europe. Bravo et al 39 also found that seeds of Solanum nigrum ingested by great bustard ( Otis tarda ) had lower germination percentage than non-ingested seeds. Furthermore, other studies on seed dispersal effectiveness in geese also described a decrease in seed germination percentage after gut passage 40 41 .…”

Germination response ofLithraea molleoidesseeds is similar after passage through the guts of several avian and a single mammalian disperser

“…This temperature regime is optimal for germination of the different species in the study area (Funes et al 2009). We used six replicates per treatment and each replicate consisted of 20 seeds placed on filter paper in 9-cm diameter Petri dishes (Bravo et al 2014). To avoid fungal growth we used an antifungal solution with bencimidazol once a week.…”