Endozoochorous dispersal by herbivores and omnivores is mediated by germination conditions
Background: Vertebrate-mediated seed dispersal is probably the main long distance dispersal mode. Through endozoochory, large mammals act as mobile links between habitats within and among forest patches. Along with other factors, their feeding regimes do affect their contribution as dispersal vectors. We conducted a cross-species comparative experiment involving two herbivores, red deer and roe deer; and two opportunistic omnivores, wild boar and brown bear, all occurring in the forest and steppe-forest ecotone habitats of the south-eastern Caspian region. We compared their role as endozoochorous seed dispersal agents by monitoring seedling emergence in their dungs under greenhouse and natural conditions.
Results: In total, 3078 seedlings, corresponding to 136 plant taxa sprouted from 445 paired dung sub-samples, under greenhouse and natural conditions. Only 336 seedlings, corresponding to 36 plant taxa, emerged under natural conditions, among which five taxa did not appear under greenhouse conditions. Graminoids and forbs composed 91% of the seedlings in the greenhouse whereas shrubs were more abundant under natural conditions, representing 55% of the emerged seedlings. Under greenhouse conditions, first red deer and then wild boar dispersed more species than the other two mammals, while under natural conditions brown bear was the most effective vector. We observed remarkably higher species richness and seedling abundance per dung sub-sample under buffered greenhouse conditions than we did under natural conditions.
Conclusions: The four sympatric mammals studied provided different seed dispersal services, both in terms of seedling abundance and species richness and may therefore be regarded as complementary. Our results highlight a positive bias when only considering germination under buffered greenhouse conditions. This must be taken into account when planning management options to benefit plant biodiversity based on the dispersal services concluded from greenhouse experiments.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
This is a list of supplementary files associated with this preprint. Click to download.
Posted 11 Aug, 2020
On 31 Aug, 2020
On 20 Jul, 2020
Received 12 Jun, 2020
Received 09 Jun, 2020
On 19 May, 2020
Invitations sent on 18 May, 2020
On 18 May, 2020
On 14 May, 2020
On 13 May, 2020
On 13 May, 2020
On 05 Feb, 2020
Received 31 Jan, 2020
Received 30 Jan, 2020
Received 24 Jan, 2020
On 17 Jan, 2020
On 15 Jan, 2020
On 15 Jan, 2020
Received 21 Nov, 2019
On 04 Nov, 2019
Invitations sent on 01 Nov, 2019
On 25 Sep, 2019
On 22 Sep, 2019
On 21 Sep, 2019
On 20 Sep, 2019
Endozoochorous dispersal by herbivores and omnivores is mediated by germination conditions
Posted 11 Aug, 2020
On 31 Aug, 2020
On 20 Jul, 2020
Received 12 Jun, 2020
Received 09 Jun, 2020
On 19 May, 2020
Invitations sent on 18 May, 2020
On 18 May, 2020
On 14 May, 2020
On 13 May, 2020
On 13 May, 2020
On 05 Feb, 2020
Received 31 Jan, 2020
Received 30 Jan, 2020
Received 24 Jan, 2020
On 17 Jan, 2020
On 15 Jan, 2020
On 15 Jan, 2020
Received 21 Nov, 2019
On 04 Nov, 2019
Invitations sent on 01 Nov, 2019
On 25 Sep, 2019
On 22 Sep, 2019
On 21 Sep, 2019
On 20 Sep, 2019
Background: Vertebrate-mediated seed dispersal is probably the main long distance dispersal mode. Through endozoochory, large mammals act as mobile links between habitats within and among forest patches. Along with other factors, their feeding regimes do affect their contribution as dispersal vectors. We conducted a cross-species comparative experiment involving two herbivores, red deer and roe deer; and two opportunistic omnivores, wild boar and brown bear, all occurring in the forest and steppe-forest ecotone habitats of the south-eastern Caspian region. We compared their role as endozoochorous seed dispersal agents by monitoring seedling emergence in their dungs under greenhouse and natural conditions.
Results: In total, 3078 seedlings, corresponding to 136 plant taxa sprouted from 445 paired dung sub-samples, under greenhouse and natural conditions. Only 336 seedlings, corresponding to 36 plant taxa, emerged under natural conditions, among which five taxa did not appear under greenhouse conditions. Graminoids and forbs composed 91% of the seedlings in the greenhouse whereas shrubs were more abundant under natural conditions, representing 55% of the emerged seedlings. Under greenhouse conditions, first red deer and then wild boar dispersed more species than the other two mammals, while under natural conditions brown bear was the most effective vector. We observed remarkably higher species richness and seedling abundance per dung sub-sample under buffered greenhouse conditions than we did under natural conditions.
Conclusions: The four sympatric mammals studied provided different seed dispersal services, both in terms of seedling abundance and species richness and may therefore be regarded as complementary. Our results highlight a positive bias when only considering germination under buffered greenhouse conditions. This must be taken into account when planning management options to benefit plant biodiversity based on the dispersal services concluded from greenhouse experiments.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5