An official website of the United States government
Abstract Seed dormancy in plants can have a significant impact on their ecology. Recent work by Rojas-Villa and Quijano-Abril (2023) classified the seed dormancy class in 14 plant species from the Andean forests of Colombia by using germination trials and several microscopy techniques to describe seed anatomy and morphology. The authors conclude thatCecropiaspecies have both physical and physiological dormancy (of which they call physiophysical dormancy) based on seed morphology and mean germination times of over 30 days. Here, we present seed permeability and germination data from neotropical pioneer tree species:Ochroma pyramidale,Cecropia longipes, andCecropia insignis, as well asCecropia peltata(present in Rojas-Villa and Quijano-Abril, 2023), to demonstrate thatCecropiaspecies do not exhibit dormancy and also have high levels of seed permeability. We find that the mean germination time for all threeCecropiaspecies in our study was less than 30 days. This suggests a need for reporting the conditions in which germination trials take place to allow for comparability among studies and using seed permeability tests to accurately identify the physical dormancy class of seeds. Further, we present data from the literature that suggests that dormancy is not a requirement for seed persistence in the seed bank.
more »
« less
Statistical inference for seed mortality and germination with seed bank experiments
- Award ID(s):
- 1754299
- PAR ID:
- 10393038
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Ecology
- ISSN:
- 0012-9658
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
null (Ed.)Seed dispersal is important for forest growth, maintenance, and regeneration. Orangutans are large-bodied frugivores with ecological roles as seed predators and seed dispersers. However, little is known about orangutans’ ecological roles and how they relate to orangutans’ patterns of frugivory. We investigated Bornean orangutans’ (Pongo pygmaeus wurmbii) ecological roles at the Cabang Panti Research Station in Gunung Palung National Park, Indonesian Borneo. We collected orangutan feces (n=401) and analyzed them for intact seeds (August 2018 to March 2020). We observed orangutan fruit handling behavior for 306 feeding bouts for 53 fruit genera to measure how often orangutans swallow, spit, or predate seeds. We used Ivlev’s Electivity Index to analyze fruit preference using long-term feeding data and phenology data (2014-2019). Lastly, we combined fruit preference with fruit handling behavior using the seed dispersal effectiveness framework to identify which fruit taxa were most effectively dispersed. Orangutans dispersed seeds in 71.8% of fecal samples with a mean of 27.9 ±4.5 (SD=0.95) seeds (>2mm) per fecal sample. Orangutans predated seeds more often than spitting or swallowing seeds (predating= 42.1% of fruit feeding time; spitting= 21.8%; swallowing= 12.5%; mixed behaviors= 10.6%, not observed=12.0%). Additionally, the top five preferred fruit genera, (Dialium, Sindora, Scaphium, Magnifera, and Spatholobus) were highly predated (0 to 5% of seeds dispersed). We identified Alangium and Tetramerista as the most effectively dispersed genera, orangutans frequently dispersed and preferred these fruits. We found orangutans are frequent seed predators, but this overlaps with their seed dispersal role, and we describe orangutans’ seed dispersal contribution. Funders: NSF (9414388, BCS-1638823, BCS-0936199); National Geographic; USFish/Wildlife (F18AP00898, F15AP00812, F13AP00920, 96200-0-G249, 96200-9-G110); Leakey; Disney Conservation Fund; Wenner-Gren; Nacey-Maggioncalda; Conservation-Food-Health; Orangutan Conservancy; Woodland Park Zoo; Boston University GRAFmore » « less
-
Abstract This study investigated ant seed removal ofPiper sancti‐felicis,an early successional Neotropical shrub. NeotropicalPiperare a classic example of bat‐dispersed plants, but we suggest that ants are underappreciated dispersal agents. We identified eleven ant species from the generaAphaenogaster,Ectatomma,Paratrechina,Pheidole,Trachymyrmex, andWasmanniarecruiting to and harvestingP. sancti‐felicisseeds in forest edge and secondary forest sites at La Selva, Costa Rica. We also tested for differences in ant recruitment to five states in which ants can commonly encounter seeds: unripe fruit, ripe fruit, overripe fruit, bat feces, and cleaned seeds. Overall, ants harvested more seeds from ripe and overripe fruits than other states, but this varied among species. To better understand the mechanisms behind ant preferences for ripe/overripe fruit, we also studied how alkenylphenols, secondary metabolites found in high concentrations inP. sancti‐felicisfruits, affected foraging behavior in one genus of potential ant dispersers,Ectatomma. We found no effects of alkenylphenols on recruitment ofEctatommato fruits, and thus, these compounds are unlikely to explain differences in ant recruitment among fruits of different maturity. Considering thatP. sancti‐felicisseeds have no apparent adaptations for ant dispersal, and few ants removed seeds that were cleaned of pulp, we hypothesize that most ants are harvesting its seeds for the nutritional rewards in the attached pulp. This study emphasizes the importance of ants as important additional dispersers ofP. sancti‐felicisand suggests that other non‐myrmecochorous, vertebrate‐dispersed plants may similarly benefit from the recruitment to fruit by ants.more » « less
-
Abstract Herbivores often have highly variable impacts on plant fecundity. The relative contribution of different environmental factors operating at varying spatial scales in affecting this variability is often unclear. We examined how density‐dependent seed predation at local scales and regional differences in primary productivity are associated with variation in the magnitude of pre‐dispersal seed predation onMonarda fistulosa(Lamiaceae). WithinM. fistulosapopulations growing in a low‐productivity region (LPR), Montana, USA, and a high‐productivity region (HPR), Wisconsin, USA, we quantified the magnitude of pre‐dispersal seed predation among individual plants differing in seed head densities. Out of a total of 303M. fistulosaplants that were surveyed, we found half as many herbivores in seed heads in the LPR (n = 133 herbivores) compared to the HPR (n = 316). In the LPR, 30% of the seed heads were damaged in plants with low seed head density, while 61% of seed heads were damaged in plants with high seed head density. Seed head damage was consistently high in the HPR (about 49% across the range of seed head density) compared to the LPR (45% across a range of seed head density). However, the proportion of seeds per seed head that were destroyed by herbivores was nearly two times higher (~38% loss) in the LPR compared to HPR (22% loss). Considering the combined effects of probability of damage and seed loss per seed head, the proportion seed loss per plant was consistently higher in the HPR regardless of seed head density. Nevertheless, because of greater seed head production, the total number of viable seeds produced per plant was higher in HPR and high‐density plants, despite being exposed to greater herbivore pressure. These findings show how large‐scale factors can interact with local‐scale factors to influence how strongly herbivores suppress plant fecundity.more » « less
