SEED REMOVAL, SEED PREDATION, AND SECONDARY DISPERSAL

Ecology ◽  
2005 ◽  
Vol 86 (3) ◽  
pp. 801-806 ◽  
Author(s):  
Stephen B. Vander Wall ◽  
Kellie M. Kuhn ◽  
Maurie J. Beck
Keyword(s):  
Seed Predation ◽  
Seed Removal ◽  
Secondary Dispersal

scholarly journals Seed germination and removal of Michelia champaca L. (Magnoliaceae) in eucalypt stands: the influence of the aril

2004 ◽  
Vol 28 (3) ◽  
pp. 327-332 ◽  
Author(s):  
Giovano Candiani ◽  
Mauro Galetti ◽  
Victor Jose Mendes Cardoso
Keyword(s):  
Seed Germination ◽  
White Light ◽  
Seed Predation ◽  
Natural Environment ◽  
Seed Removal ◽  
Controlled Conditions ◽  
Removal Experiments ◽  
Michelia Champaca

We tested the influence of the aril on seed germination in controlled conditions and on the removal of M. champaca seeds in natural environment. Germination assays were kept at 25 ± 2 °C under continuous white light. Removal experiments were carried out in three "old" (39 to 62-years old) and three "new" (15-years old) eucalypt stands in Horto Florestal Navarro de Andrade, Rio Claro, SP. The results show that the aril inhibits the germination and the seeds exhibit a positively photoblastic reaction. We found higher seed removal in old eucalypt stands than the new ones, probably due to the higher density of rodents in the old stands. In the new stands, we found higher seed removal of arillated seeds by ants. Ants are important to remove the aril of seeds dropped by birds, not only enhancing seed germination but also preventing seed predation by rodents.

Two-stage dispersal of Guarea glabra and G. kunthiana (Meliaceae) in Monteverde, Costa Rica

1999 ◽  
Vol 15 (4) ◽  
pp. 481-496 ◽  
Author(s):  
Daniel G. Wenny
Keyword(s):  
Costa Rica ◽  
Seed Dispersal ◽  
Seed Predation ◽  
Soil Surface ◽  
Vegetation Density ◽  
Seed Shadow ◽  
Secondary Dispersal ◽  
Germination Success ◽  
Tayassu Tajacu ◽  
Para Determinar

Seed dispersal of Guarea glabra and G. kunthiana (Meliaceae) in Monteverde, Costa Rica was studied to determine how seed predation and secondary dispersal affect the distribution of seeds available for recruitment. The arillate seeds are consumed mainly by birds that regurgitate or defecate the seeds intact. After dispersal, 45.6% of G. glabra and 26.6% of G. kunthiana seeds were buried 1–3 cm in the soil, presumably by scatterhoarding rodents such as agoutis (Dasyprocta punctata). G. glabra seeds that were not cached were eaten mostly by beetles, and 33.7% of the seeds remained cached after 12 wk. The cached G. glabra seeds did not germinate, however, perhaps as a result of experimental procedures used to mark the seeds. In greenhouse experiments, G. glabra seeds buried to mimic scatterhoarding had higher germination success than seeds on the soil surface. G. kunthiana seeds not cached were eaten by peccaries (Tayassu tajacu) and other seed predators (60%) or were inviable (10%). Only nine (7.5%) viable G. kunthiana seeds remained in caches after 12 wk. Secondary dispersal resulted in a rearrangement of the seed shadow. G. glabra seeds were moved to sites with less leaf litter and lower vegetation density, while G. kunthiana seeds were moved farther from conspecific trees and closer to fallen logs during secondary dispersal. Considering the high rates of seed predation in the field for both species, the germination advantages for G. glabra in the greenhouse, and the shifts in microhabitat during scatterhoarding, it is likely that secondary dispersal by scatterhoarding rodents is an important stage in Guarea recruitment.RESUMEN. Dispersión de semillas de Guarea glabra y G. kunthiana (Meliaceae) en Monteverde, Costa Rica fureon examinadas para determinar como la predación de semillas y dispersión secundaria afectan la distribución de semillas disponibles para recrutamiento. Las semillas ariladas son consumidas principalmente por aves que regurgitan o defecan la semilla intacta. Luego de dispersión, 30–45% de las semillas fueron enterradas 1–3 cm en el suelo, posiblemente por roedores que disperan y acumulan como al agouti (Dasyprocta puncaata). Semillas de G. kunthiana que no fueron escondidas fueron comidas por pécaris (Tayassu tajacu) y otros predadores de semillas (60%) o no fueron viables (10%). Solo neuve (7.5%) semillas viables de G. kunthiana permanecieron en los escondites luego de 12 semanas. En contraste, semillas de G. glabra que no fueron escondidas fueron comidas mayormente por escarabajos que por pécaris, y 33.7% de las semillas permanecieron escondidas luego de 12 semanas. Las semillas esconditas de G. glabra enterradas para imitar dispersión y acumulión tuvieron una germinación mayor que semillas en la superficie del suelo. Dispersión secundaria resulto en un rearreglo de la sombra de semillas. Las dos especies experimentaron un leve aumento neto en la distancia promedio de conspecificos en frutos luego de dispersión y acumulación. Semillas de G. kunthiana fueron movidas cerca de troncos caidos durante dispersión secundaria, mientras semillas de G. glabra fueron movidas a lugares con menos lecho de hojas y baja densidad de vegetación. Considerando la alta proporción de predación de semillas en el campo para ambas especies, la ventaja de germinación de G. glabra en el invernáculo, y el cambio en micrambiente durante dispersión y acumulación, es posible que dispersión secundaria por roedores que dispersan y acumulan es importante in etapas de recrutamiento en Guarea.

Post-dispersal seed predation and seed bank persistence

1998 ◽  
Vol 8 (4) ◽  
pp. 513-519 ◽  
Author(s):  
P. E. Hulme
Keyword(s):  
Seed Size ◽  
Seed Bank ◽  
Seed Predation ◽  
Negative Relationship ◽  
Seed Mass ◽  
Seed Banks ◽  
Seed Removal ◽  
Seed Predators ◽  
Grassland Plants ◽  
Buried Seeds

AbstractThis study examines whether post-dispersal seed predators could be an important selective force in determining the seed bank strategies of grassland plants. It tests the hypothesis that species with persistent seed banks should sustain proportionally less predation of buried seeds than species which have transient seed banks and that this should be true irrespective of seed size. Results are drawn from a field experiment examining the relative susceptibility of surface versus buried seeds for 19 herbaceous taxa exhibiting different degrees of seed bank persistence. The data were consistent with the hypothesis that seed predators (rodents) influence the seed bank characteristics of seeds. Rodents removed proportionally more large seeds than small seeds and removed a smaller proportion of seeds with persistent rather than transient seed banks, independently of seed size. On average, burial reduced seed removal by almost 50%. The decrease in rates of seed removal following burial was marked for seeds with persistent seed banks but negligible for seeds with transient seed banks. Herbaceous plants with relatively large seeds (seed mass > 1 mg) that form persistent seed banks were either completely avoided or only consumed in small quantities by rodents. In contrast, large-seeded species with transient seed banks suffer high rates of seed predation. Models of life-history evolution predict trade-offs between seed dormancy and seed mass since dormancy and seed size are correlated traits that both reduce risk in variable environments and thus will show patterns of negative covariation. This paper presents an alternative explanation for this trade-off based on experimental evidence of a negative relationship between seed bank persistence and predation risk.

Dispersal of Aglaia spectabilis, a large-seeded tree species in a moist evergreen forest in Thailand

2004 ◽  
Vol 20 (4) ◽  
pp. 421-427 ◽  
Author(s):  
Shumpei Kitamura ◽  
Shunsuke Suzuki ◽  
Takakazu Yumoto ◽  
Pilai Poonswad ◽  
Phitaya Chuailua ◽  
...  
Keyword(s):  
Seed Predation ◽  
Tree Species ◽  
Forest Floor ◽  
National Park ◽  
Evergreen Forest ◽  
Seed Removal ◽  
Mammal Species ◽  
Seed Predator ◽  
Khao Yai National Park ◽  
Frugivore Assemblages

We investigated the seed dispersal of Aglaia spectabilis, a large-seeded tree species in a moist evergreen forest of Khao Yai National Park in Thailand. Although one-to-one relationships between frugivores and plants are very unlikely, large-seeded plants having to rely on few large frugivores and therefore on limited disperser assemblages, might be vulnerable to extinction. We assessed both the frugivore assemblages foraging on arillate seeds of Aglaia spectabilis and dispersing them and the seed predator assemblages, thereby covering dispersal as well as the post-dispersal aspects such as seed predation. Our results showed that frugivores dispersing seeds were a rather limited set of four hornbill and one pigeon species, whereas two squirrel species were not dispersers, but dropped the seeds on the ground. Three mammal species were identified as seed predators on the forest floor. Heavy seed predation by mammals together with high seed removal rates, short visiting times and regurgitation of intact seeds by mainly hornbills lead us to the conclusion that hornbills show high effectiveness in dispersal of this tree species.

Removal of seeds of Carapa procera (Meliaceae) by rodents and their fate in rainforest in French Guiana

1996 ◽  
Vol 12 (6) ◽  
pp. 751-761 ◽  
Author(s):  
Pierre-Michel Forget
Keyword(s):  
Seed Predation ◽  
Tree Species ◽  
French Guiana ◽  
Removal Rate ◽  
Seed Removal ◽  
Seed Fate ◽  
Wet Season ◽  
Adult Trees ◽  
Carapa Procera ◽  
Monthly Variations

ABSTRACTExperiments were performed to investigate monthly variations in seed fate of Carapa procera (Meliaceae), a rodent-dispersed subcanopy tree species in French Guiana. A total of 600 thread-marked seeds were placed on the ground in mature forest under 20 adult trees during different months (March, April and May 1991) of the species' fruiting season. In 1991 the seed crop reached 1536 seeds in the study area, with a majority of seeds being produced in March and May. On average, seed removal rate steadily increased from March (23%) to May (96%). Of the seeds removed, the proportion eached almost doubled between March (28%)-April (25%) and May (48%), whereas the proportion eaten (gnawed) steadily declined between March (43%) and May (9%). Approximately 75–100% seed removal was therefore associated with intense scatterhoarding and low seed predation, especially in May. Greater seed dispersal rates occurred during the late wet season when fruit diversity decreased but when overall fruit biomass peaked because of fruiting occurrence of large-seeded species. The seasonal hoarding behaviour of rodents is discussed.

scholarly journals Secondary seed removal in a degraded forest habitat in Madagascar

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paula M. A. Fiedler ◽  
Alice De Lapparent ◽  
Jeremie Razafitsalama ◽  
Justin Sanamo ◽  
Kim J. E. Steffens ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Seed Predation ◽  
Tree Species ◽  
Natural Regeneration ◽  
Forest Restoration ◽  
Forest Degradation ◽  
Degraded Forest ◽  
Seed Removal ◽  
Forest Habitat ◽  
Removal Experiments

AbstractForest restoration is a prime goal within the 2021–2030 UN “Decade of Ecosystem Resoration”. As part of these activities, natural regeneration has to be promoted for biological as well as for economic reasons. For this, the processes of seed dispersal, seed predation and germination have to be understood in the original as well as in degraded vegetation formations. We used seed removal experiments to assess post-dispersal processes that influence recruitment along a gradient of forest degradation in Madagascar analyzing seeds of three animal dispersed tree species. The percentage of seeds consumed or dispersed, declined from forest (28.6%) to degraded forest (17.2%) to savanna (10.8%). Only three out of 1080 seeds were cached and remained intact during the 14-day experiment. All three seeds were cached in the forest habitat and none in the degraded forest and savanna. The low percentage of seeds removed may be due to the lack of endemic rodents caching seeds, as only introduced rats were recorded in the area. The species-poor fauna of potential secondary seed dispersers of the region and especially in the degraded areas might represent an obstacle for diverse regeneration in degraded regions of Madagascar.

Influence of fire, topography, and consumer abundance on seed predation in tallgrass prairie

2004 ◽  
Vol 82 (9) ◽  
pp. 1459-1467 ◽  
Author(s):  
Aaron W Reed ◽  
Glennis A Kaufman ◽  
Donald W Kaufman
Keyword(s):  
Tallgrass Prairie ◽  
Seed Predation ◽  
Fire Frequency ◽  
Time Of Day ◽  
Plant Litter ◽  
Seed Removal ◽  
Litter Layer ◽  
Topographic Positions ◽  
In Fire ◽  
Diurnal Period

We assessed seed predation by vertebrates and invertebrates in three fire-frequency treatments (<1 year, 1–4 years, and >4 years since fire) and in three topographic positions (upland, limestone breaks, and lowland) in tallgrass prairie. Two types of seed trays, one for vertebrates and one for invertebrates, were placed in each treatment during each nocturnal and diurnal period. Vertebrates removed significantly more seeds than did invertebrates. Fire frequency and topographic position affected seed removal by both vertebrates and invertebrates. Seed removal by invertebrates was influenced negatively by fire; the greatest seed removal occurred in uplands and lowlands in unburned prairie. Vertebrates removed the most seeds in burned prairie and in lowlands and limestone breaks. Time of day also influenced seed removal by vertebrates, as nocturnal vertebrates (assumed to be rodents) removed more seeds than diurnal vertebrates. Abundance of rodents, however, did not predict accurately seed removal in fire treatments or topographic positions, as rodents removed fewer seeds than expected in prairie that had not been burned in >4 years and in lowlands. This pattern likely was due to the presence of a well-developed plant litter layer in both unburned and lowland habitats, which reduces the likelihood of a rodent locating seeds.

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