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1
Baker, F. A., and D. W. French. "Dispersal of Arceuthobiumpusillum seeds." Canadian Journal of Forest Research 16, no. 1 (February 1, 1986): 1–5. http://dx.doi.org/10.1139/x86-001.
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Seed dispersal of Arceuthobiumpusillum Peck on Piceamariana (Mill.) B.S.P. was studied at two locations in Minnesota from 1974–1980. Seed dispersal began as early as August 23 and was observed as late as September 27. Most seeds were dispersed in the mornings between 0400 and 0900. The mean annual distance of dispersal ranged from 1.0 to 2.3 m. The density of seeds trapped on the plots ranged from 4.2 to 16.7 seeds/m2. At both locations, the number of seeds trapped outside the stand decreased logarithmically with distance from the source trees. Within stands, seeds were more frequently trapped 1–4 m from source trees than under them. Most seed dispersal occurred 1-3 days after rain. Seeds were dispersed normally on 23 of 30 days when minimum temperatures were less than 0 °C. Fruit abortion was noted on four occasions. Insects were not found to carry dwarf mistletoe seeds.
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Roxburgh, Lizanne. "The effect of gut processing on the quality of mistletoe seed dispersal." Journal of Tropical Ecology 23, no. 3 (April 24, 2007): 377–80. http://dx.doi.org/10.1017/s0266467407004014.
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Disperser effectiveness is the contribution that a disperser makes to the future reproduction of a plant (Schupp 1993), and it has two components: quality and quantity of dispersal. Quantity of dispersal is a function of the number of visits that a disperser makes to a fruiting plant and the number of seeds that are dispersed during each visit. Quality of dispersal is a function of the treatment that a seed receives from its disperser and the site that the seed is finally deposited in. The quality of seed dispersal of the mistletoe Phragmanthera dschallensis (Engl.) M.G. Gilbert (Loranthaceae) by frugivorous birds was examined in this study.
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Stevenson, Pablo, and Adriana Guzmán. "Seed dispersal, habitat selection and movement patterns in the Amazonian tortoise, Geochelone denticulata." Amphibia-Reptilia 29, no. 4 (2008): 463–72. http://dx.doi.org/10.1163/156853808786230442.
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AbstractThe Amazonian tortoise Geochelone denticulata may play an important role in forest dynamics due to its highly frugivorous diet, ability to disperse viable seeds, and predilection for resting in forest gaps for thermoregulation. The purpose of our study was to evaluate the species' effectiveness as a seed disperser. We measured dispersal quantity (abundance of seeds in feces, frequency of droppings, and population density of the disperser) and dispersal quality (movement patterns, habitat use, germination rates of dispersed seeds, and recruitment probabilities of seedlings) in a SW Amazonian forest, in Peru. Population density was calculated by mark-recapture and line-transect methods. Eight individuals were radio-tracked to monitor habitat use. Diet was described from fecal samples, which were washed to count seeds and for germination experiments. Seedling survival in different environmental conditions was monitored for three plant species. Population densities with mark-recapture estimates (0.15-0.31 individuals/ha) were much higher than with line transects estimates (0.0025 individuals/ha). Diet included fruit of 55 different plant species. Dispersed seeds had high germination rates (average 76%). In spite of their low activity, we documented long seed dispersal distances (average 89.6 m). Tortoises showed a marked preference for the open-canopy swampy forest, where long term recruitment was not favorable for seedlings of the species examined. However, the high solar radiation in this forest type promoted survival of pioneer seedlings in the short term. In conclusion, while G. denticulata did not perform a very efficient role in terms of the quantity of seed dispersal, the species can be considered efficient in many aspects of dispersal quality.
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Pairon, Marie, Mathieu Jonard, and Anne-Laure Jacquemart. "Modeling seed dispersal of black cherry, an invasive forest tree: how microsatellites may help?" Canadian Journal of Forest Research 36, no. 6 (June 1, 2006): 1385–94. http://dx.doi.org/10.1139/x06-018.
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We used empirical models and three dispersal functions (Weibull, lognormal and 2Dt) to model seed distributions derived from the black cherry (Prunus serotina Ehrh.) understorey of a pine-dominated stand. Two different approaches were used to disentangle the overlapping seed shadows: the traditional inverse modeling approach and the genetic approach that uses microsatellite markers to assign a dispersed seed to its maternal parent. The distinction was made between the seeds passively dispersed by gravity (fruits with mesocarp) and those dispersed by birds (fruits without mesocarp). Our main objectives were to compare the three dispersal functions and assess the differences between the two approaches used. The functions performed equally well, but the lognormal function often showed a better data correlation. The best dispersal curves obtained by both traditional and genetic approaches were quite similar for the seeds dispersed by gravity, and 95% of these seeds were predicted to fall 5 and 3 m away from the parent tree for the traditional and genetic approaches, respectively. Differences were more important for the seeds dispersed by birds. The traditional approach predicted a lower number of seeds near the parent plant and a higher dispersal distance. Microsatellites provided accurate information on individual dispersal events and led to a better insight into the dispersal process.
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Barroso, Judit, Dionisio Andújar, Carolina San Martín, César Fernández-Quintanilla, and José Dorado. "Johnsongrass (Sorghum halepense) Seed Dispersal in Corn Crops under Mediterranean Conditions." Weed Science 60, no. 1 (March 2012): 34–41. http://dx.doi.org/10.1614/ws-d-11-00099.1.
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Natural dissemination of johnsongrass seeds as well as the effect of combine harvesting on this process were studied in corn fields. The estimation of natural dispersal was carried out by two different methods, collecting seeds throughout the season using seed traps and sampling soil–surface seed abundance before harvest using a vacuum device. Both methods showed the same dispersal pattern. A minimum of 84.6% was dispersed in the first 2 m from the focus and a maximum of 1.6% was dispersed beyond the first 5 m. An average of 76.3% of these dispersed seeds were lost or buried after shedding but before harvest. Seed dispersal by the combine harvester was estimated from the difference between soil–surface seed abundance in the same sites pre and postharvest. Although the quantity of seeds dispersed by the combine was similar to those dispersed by natural factors, dispersal distances were significantly higher. Around 90% of the dispersed seeds were found in the first 5 m forward and backward of the combine direction from the infestation source, and 1.6% of the seeds were found beyond 22 m forward and 10 m backward of the combine direction from the infestation source. A large proportion of the seeds dispersed were dormant or not viable. It is concluded that the major role of sexual reproduction in johnsongrass population dynamics may be to spread the risks, promoting dispersal in time and space.
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Moses, Kara L., and Stuart Semple. "Primary seed dispersal by the black-and-white ruffed lemur (Varecia variegata) in the Manombo forest, south-east Madagascar." Journal of Tropical Ecology 27, no. 5 (August 2, 2011): 529–38. http://dx.doi.org/10.1017/s0266467411000198.
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Abstract:Seed dispersal is a pivotal ecological process but remains poorly understood on Madagascar, where lemurs are key dispersers. The black-and-white ruffed lemur (Varecia variegata) possesses many behavioural and ecological attributes potentially conducive to effective seed dispersal, but no studies have investigated dispersal patterns in this species. This 3-mo study quantified aspects of the primary seed dispersal patterns generated by two Varecia variegata groups (7 individuals). Feeding and ranging behaviour was quantified using behavioural observation (345.6 h), dispersal quantity and seed identity was determined by faecal analysis, and 10-wk germination trials tested effects of gut passage on germination of four species. Individual lemurs dispersed an estimated 104 seeds d−1, of 40 species. Most seeds were large (>10 mm); the largest was 42 mm long. Gut passage was rapid (mean 4.4 h) and generally increased germination speed and success. Mean and maximum inferred dispersal distances were 180 and 506 m respectively; low compared with many anthropoids, but possibly typical of lemurs. Though limited by a short study period, results suggest that the ruffed lemur is an effective disperser of seeds and possibly a critical disperser of large-seeded species which other frugivores cannot swallow. Loss of large-bodied seed dispersers such as Varecia variegata may have far-reaching ecological consequences including impacts on forest structure and dynamics.
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Chapman, Colin A. "Primate Seed Dispersal: The Fate of Dispersed Seeds." Biotropica 21, no. 2 (June 1989): 148. http://dx.doi.org/10.2307/2388705.
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Sahley, Catherine Teresa, Klauss Cervantes, Edith Salas, Diego Paredes, Victor Pacheco, and Alfonso Alonso. "Primary seed dispersal by a sigmodontine rodent assemblage in a Peruvian montane forest." Journal of Tropical Ecology 32, no. 2 (March 2016): 125–34. http://dx.doi.org/10.1017/s0266467416000043.
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Abstract:We examined quantity and quality components of primary seed dispersal for an assemblage of sigmodontine rodents in a high-elevation montane tropical forest in Peru. We collected faecal samples from 134 individuals belonging to seven rodent species from the subfamily Sigmodontinae (Cricetidae) over a 2-y period. We conducted seed viability tests for seeds found in faecal samples. We identified seeds from eight plant families (Bromeliaceae, Annonaceae, Brassicaceae, Ericaceae, Melastomatacae, Myrtaceae, Rosaceae, Solanaceae), nine genera and 13 morphospecies. The most abundant seeds belonged toGaultheriasp. 1 (46% of total) andMiconiasp. 1 (31% of total), while the most viable seeds belonged toGreigiasp. (84% viability) andGuatteriasp. (80% viability). We utilized relative rodent abundance, seed species diversity, seed abundance and seed viability per rodent species to calculate an index of rodent disperser effectiveness, and found thatThomasomys kalinowskiiwas the most effective disperser, followed byAkodon torques,Calomys sorellus,Thomasomys oreas,Oligoryzomys andinusandMicroryzomys minutus. Plant genera dispersed by sigmodontine rodents overlapped more with bird- and terrestrial-mammal-dispersed plants than with bat-dispersed plants. Future neotropical seed dispersal studies should consider small rodents as potential seed-dispersers, especially in tropical habitats where small-seeded, berry-forming shrubs and trees are present.
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Dorp, D. van, W. P. M. van den Hoek, and C. Daleboudt. "Seed dispersal capacity of six perennial grassland species measured in a wind tunnel at varying wind speed and height." Canadian Journal of Botany 74, no. 12 (December 1, 1996): 1956–63. http://dx.doi.org/10.1139/b96-234.
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The dispersal capacity of six perennial grassland species with different seed aerodynamic attributes was assessed in a wind tunnel. The selected species have difficulty in recolonizing restored ecosystems because of a poor dispersal of seeds. The variation in dispersal distances of seeds within and between species was assessed by releasing seeds at varying wind speeds and release heights, and expressed as 1st percentile, mode, and 99th percentile values. Dispersal distances of long-range dispersed seeds (99th percentile values) increased exponentially with wind speed. At wind speeds of 14 m/s, predicted maximum distances are 10–15 m for small and relatively heavy spherical seeds and 20–30 m for large and relatively light cylindrical or disk-like seeds. In the study area, wind gusts > 10 m/s at plant height occur at least annually, and plants of the selected species live up to several decades. This suggests a great potential for long-range dispersal during the lifetime of a plant. Plants may gain wider dispersal of seeds by increasing the release height (e.g., taller infructescences) and by requiring stronger winds to release seeds (e.g., dispersal in autumn and winter). Keywords: dispersal, wind tunnel, seeds, perennial, wind gust.
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Kankam, Bright Obeng, and William Oduro. "Frugivores and fruit removal ofAntiaris toxicaria(Moraceae) at Bia Biosphere Reserve, Ghana." Journal of Tropical Ecology 25, no. 2 (March 2009): 201–4. http://dx.doi.org/10.1017/s0266467409005835.
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In tropical forests, most individual fruit-bearing trees depend on frugivores for seed dispersal (Howe & Smallwood 1982, Wilson 1992). Seed dispersal enhances germination potential, provides an opportunity for seeds to escape predation under the parent plants, and reduces seedling numbers under parent trees (Şekercioğluet al. 2004). The way frugivores handle seeds and process them may influence the seed fate of many plants (Janzen 1971). The quantity of seeds dispersed and the quality of dispersal provided by frugivores impact plant fitness (Herrera & Jordano 1981). Schupp (1993) defined the effectiveness of seed dispersal by frugivores as an empirical measure of quantity of seeds dispersed and quality of dispersal from the parent plant to a suitable microsite. Seed dispersal by frugivores increases the chances for seedling survival away from the vicinity of the parent plant because in tropical forests seed predation is concentrated under adult trees that prevent seedlings from establishing near parent trees (Howe & Miriti 2004).
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Velázquez-Vázquez, Guadalupe, Arturo González-Zamora, Víctor Arroyo-Rodríguez, and Joseph Taylor. "Seed dispersal by spider monkeys in logged and unlogged sites in the Calakmul tropical humid forest, Mexico / Dispersión de semillas por monos araña en sitios talados y no talados en el bosque húmedo tropical de Calakmul, México." Brazilian Journal of Animal and Environmental Research 5, no. 1 (January 21, 2022): 247–55. http://dx.doi.org/10.34188/bjaerv5n1-022.
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Seed dispersal by animals can be negatively affected by selective logging, but effects such changes in critical food resource, quality of food resources and food availability on seed dispersal and seedling recruitment, remains poorly understood. We investigated how selective logging, impacts the quantity of seed dispersal, focusing on highly frugivorous primate Ateles geoffroyi yucatanensis in Calakmul, Mexico. We assessed whether seed dispersal by the spider monkey differs between a logged and an unlogged site in the Calakmul tropical humid forest, Mexico. We recorded seeds in monkey faeces, including those deposited in latrines under sleeping trees (aggregated seed dispersal) and those dispersed across the forest (scattered seed dispersal) during a 5-mo period. The use of sleeping tree was similar in both forest conditions, averaging (± SD) 4.5 ± 4.3 weeks. They deposited 15,853 seeds (1–35 mm in length) from 20 tree species under sleeping trees, but seed abundance was 2.2 times higher in unlogged forests. Scattered seed dispersal (997 seeds from nine species) followed the opposite pattern, with 2.3 times more seeds in logged forests. The number of seeds and species per faecal sample did not differ between forest types, averaging 9.4 ± 20.2 seeds from 1.0 ± 0.8 seed species. Most (95%) scatter-dispersed seeds were undamaged in both forest types. These findings suggest that primate quantity seed dispersal is not limited in logged forests, potentially contributing to the recovery of these managed forests.
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Farias, J., M. Sanchez, M. F. Abreu, and F. Pedroni. "Seed dispersal and predation of Buchenavia tomentosa Eichler (Combretaceae) in a Cerrado sensu stricto, midwest Brazil." Brazilian Journal of Biology 75, no. 4 suppl 1 (November 24, 2015): 88–96. http://dx.doi.org/10.1590/1519-6984.06214.
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Abstract The ecology of seed dispersal is critical to understand the patterns of distribution and abundance of plant species. We investigated seed dispersal aspects associated with the high abundance of Buchenavia tomentosa in the Serra Azul State Park (PESA). We estimated fruit production and conducted fruit removal experiments. We carried out diurnal and nocturnal observations on frugivory as well as germination tests. Fruiting occurred in the dry season and totaled 1,365,015 ± 762,670 fruits.ha–1. B. tomentosa fruits were utilized by eight animal species. The lowland tapir (Tapirus terrestris) was considered the main seed disperser. Leafcutter ants (Atta laevigata and Atta sexdens) participated in the seed cleaning and occasionally dispersed seeds. The beetle Amblycerus insuturatus, blue-and-yellow macaw (Ara ararauna) and red-and-green macaw (Ara chloropterus) were considered pre-dispersal seed predators. The seeds manually cleaned presented higher germination rate (100%) and speed index (4.2 seeds.d–1) than that of seeds with pulp. Germination of seeds found in tapirs’feces was 40%, while for the seeds without pulp it was 25%. The high abundance of B. tomentosa in the cerrado of PESA may be due to massive fruit production, low rates of seed predation, and efficient seed dispersal by tapirs, occurring before the rains which promote germination and recruitment of this species.
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Yang, Wenjie, Fude Liu, Shiting Zhang, and Shuqing An. "Dispersal and germination syndromes of tree seeds in a seasonal evergreen monsoon rainforest on Hainan Island, China." Seed Science Research 23, no. 1 (January 3, 2013): 41–55. http://dx.doi.org/10.1017/s0960258512000293.
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AbstractThis paper examines the dispersal–germination strategy of seeds of 66 native tree species from a seasonal evergreen monsoon rainforest on Hainan Island, China, and assesses correlations among seed germination and phylogeny, dispersal mode and dispersal season. Seeds of 15, 7, 25 and 19 species were dispersed during the warm dry (March–May), rainy (June–September), late rainy (October–November) and cool dry (December–February) seasons, respectively. Berries (16 species), drupes (14 species) and capsules (12 species) were common and represented about 64% of the species. Zoochory was the most common dispersal mode (69.7%) followed by anemochory (16.7%) and autochory (13.6%). More than 65% of species had dormant seeds. Based on germination speed and synchrony, six patterns were recognized: rapid and synchronous germination (13 species), intermediate and synchronous germination (3 species), intermediate and intermediately synchronous germination (24 species), intermediate and asynchronous germination (2 species), slow and intermediately synchronous germination (5 species), and slow and asynchronous germination (19 species). One-way ANOVAs revealed that the variance in germination percentages among species was largely dependent upon phylogeny. The mean and median length of germination (MLG) were largely dependent upon phylogeny, dispersal mode and dispersal season. Anemochorous seeds germinated faster than autochorous and zoochorous seeds. Seeds dispersed in the late dry or early rainy season (March–May) tended to germinate quickly, whereas those dispersed towards the end of the rainy season and into the cool dry season are likely to have a much longer length of dormancy. Correlation analyses indicated that larger seeds germinated faster and had higher germination percentages.
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Gorchov, David L., Jorge M. Palmeirim, and Cesar F. Ascorra. "Dispersal of seeds of Hymenaea courbaril (Fabaceae) in a logged rain forest in the Peruvian Amazonian." Acta Amazonica 34, no. 2 (2004): 251–59. http://dx.doi.org/10.1590/s0044-59672004000200014.
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Seed dispersal of Hymenaea courbaril was studied by following the fate of 585 seeds embedded with small magnets and set in displays in and near a logged strip in rain forest in the Peruvian Amazonian. Mammals took fruits from all displays, which were located in the forest, edge, and cleared strip. Overall removal rates were low - a median of 8.1 fruits / month from displays maintained with 8-10 fruits - but were higher in August than in earlier months. Most fruits were dropped near the display or had their seeds eaten, but > 13% were successfully dispersed. Most of the dispersed seeds were buried, which increases probability of germination. Maximum dispersal distance of live seeds was 12.1 m (median 3.1 m), but other magnets were transported up to 34 m, indicating seeds were dispersed further, but then eaten. Acouchies (most likely Myoprocta pratti) and agoutis (Dasyprocta fuliginosa) were apparently the main dispersal agents. Dispersal of seeds from the forest into the logged strip was rare, suggesting that although rodents disperse H. courbaril, they cannot be relied on for the reseeding this and similar species in recent clearings.
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GITHIRU, MWANGI, LEON BENNUN, and LUC LENS. "Regeneration patterns among bird-dispersed plants in a fragmented Afrotropical forest, south-east Kenya." Journal of Tropical Ecology 18, no. 1 (January 2002): 143–49. http://dx.doi.org/10.1017/s0266467402002092.
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Fruit-eating birds play an important role in the seed dispersal of many tropical plants (e.g. Herrera 1984), and the foraging behaviour of avian frugivores may affect their seed-dispersal capabilities (Loiselle & Blake 1999,Schupp 1993, Traveset 1994). For instance,shorter visits tend to produce less clumped seed distributions (Graham et al. 1995). Also,avian frugivores often feed on the fruits of several plant species over short periods of time (Herrera 1984, 1988a; Levey et al. 1994) in some non-random pattern (Herrera 1998). This potentially produces a predictable spatial pattern of the dispersed seeds (White & Stiles 1990). Forest destruction leads to fragmentation and degradation of the remaining habitats, which may influence patterns of adult tree distribution if the production, predation, dispersal, and/or regeneration of tree seeds is affected (Harrington et al. 1997). If dispersal of avian frugivores is disrupted by habitat fragmentation, plant species might face reduced regeneration, or even local extinction if they depend on a single, locally extinct disperser (Kellman et al. 1996). Increased predation of seeds and regenerating plants in the edges and gaps may also directly reduce regeneration rates (Corlett & Turner 1997, Harrington et al. 1997, Schupp 1988).
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Hanson, Thor, Steven Brunsfeld, Bryan Finegan, and Lisette Waits. "Conventional and genetic measures of seed dispersal for Dipteryx panamensis (Fabaceae) in continuous and fragmented Costa Rican rain forest." Journal of Tropical Ecology 23, no. 6 (October 29, 2007): 635–42. http://dx.doi.org/10.1017/s0266467407004488.
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The effects of habitat fragmentation on seed dispersal can strongly influence the evolutionary potential of tropical forest plant communities. Few studies have combined traditional methods and molecular tools for the analysis of dispersal in fragmented landscapes. Here seed dispersal distances were documented for the tree Dipteryx panamensis in continuous forest and two forest fragments in Costa Rica, Central America. Distance matrices were calculated between adult trees (n = 283) and the locations of seeds (n = 3016) encountered along 100 × 4-m transects (n = 77). There was no significant difference in the density of seeds dispersed > 25 m from the nearest adult (n = 253) among sites. There was a strong correlation between the locations of dispersed seeds and the locations of overstorey palms favoured as bat feeding roosts in continuous forest and both fragments. Exact dispersal distances were determined for a subset of seeds (n = 14) from which maternal endocarp DNA could be extracted and matched to maternal trees using microsatellite analysis. Dispersal within fragments and from pasture trees into adjacent fragments was documented, at a maximum distance of 853 m. Results show no evidence of a fragmentation effect on D. panamensis seed dispersal in this landscape and strongly suggest bat-mediated dispersal at all sites.
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Davies, Kirk W., and Roger L. Sheley. "Influence of Neighboring Vegetation Height on Seed Dispersal: Implications for Invasive Plant Management." Weed Science 55, no. 6 (December 2007): 626–30. http://dx.doi.org/10.1614/ws-07-067.1.
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Controlling invasive plant infestations is very costly and often unsuccessful. Preventing invasions is more cost-effective than controlling invasive plants after they are established. Because prevention guidelines do not suggest any tools or methods to limit wind dispersal of invasive plant seeds, we investigated the influence of neighboring vegetation height on seed dispersal of a wind-dispersed (yellow salsify) and nonwind-dispersed (medusahead) species. To examine the influence of neighboring vegetation height on dispersal, seeds of both species were released in front of an artificial stand of desert wheatgrass in a modified wind tunnel. Treatments were a complete factorial design with two species, four vegetation heights (10, 30, 40, and 60 cm), three wind speeds (3, 5.5, and 10 km h−1), and three release distances from the neighboring vegetation (0, 15, and 30 cm). The ability of medusahead and yellow salsify seeds to disperse was influenced by the height of neighboring vegetation. Increasing height of neighboring vegetation decreased the number of yellow salsify seeds dispersing across neighboring vegetation. The greatest percentage of medusahead seeds dispersed across the neighboring vegetation was at the shortest height. Based on these results, we suggest that maintaining or promoting tall vegetation neighboring invasive plant infestations may reduce wind dispersal of seeds. More research is needed to investigate the influence of varying heights, densities, structural attributes, and composition of vegetation neighboring infestations and the dispersal of invasive plants.
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Greene, D. F., and E. A. Johnson. "Long-distance wind dispersal of tree seeds." Canadian Journal of Botany 73, no. 7 (July 1, 1995): 1036–45. http://dx.doi.org/10.1139/b95-113.
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Long-distance seed dispersal figures prominently in most plant conservation biology arguments, yet we possess little more than anecdotes concerning the relationship among deposition (seeds/m2), source strength (seeds/m2), and distance. In this paper we derive two simple models for long-distance deposition. The models are tested at the scale of 100–1600 m from the source and found to be within 5-fold of the observed deposition. There is no discernable decline in deposition for the range 300–1600 m. While we hesitate to extend model predictions to greater distances, both the models and the empirical results allow us to assert that rare wind-dispersed species in woodlots (dispersal distance around 1 km) are effectively isolated from one another at the temporal scale of 1000 years. Key words: plant conservation biology, wind dispersal of seeds, metapopulations.
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Foster, Mercedes S., and Linda S. Delay. "Dispersal of mimetic seeds of three species of Ormosia (Leguminosae)." Journal of Tropical Ecology 14, no. 4 (July 1998): 389–411. http://dx.doi.org/10.1017/s0266467498000303.
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ABSTRACT. Seeds with ‘imitation arils’ appear wholly or partially covered by pulp or aril but actually carry no fleshy material. The mimetic seed hypothesis to explain this phenomenon proposes a parasitic relationship in which birds are deceived into dispersing seeds that resemble bird-dispersed fruits, without receiving a nutrient reward. The hard-seed for grit hypothesis proposes a mutualistic relationship in which large, terrestrial birds swallow the exceptionally hard mimetic seeds as grit for grinding the softer seeds on which they feed. They defecate, dispersing the seeds, and abrade the seed surface, enhancing germination. Any fruit mimicry is incidental. Fruiting trees of Ormosia spp. (Leguminosae: Papilionoideae) were observed to ascertain mechanisms of seed dispersal and the role of seemingly mimetic characteristics of the seeds in that dispersal. Seed predation and seed germination were also examined. Ormosia isthamensis and O. macrocalyx (but not O. bopiensis) deceived arboreally-foraging frugivorous birds into taking their mimetic seeds, although rates of seed dispersal were low. These results are consistent with the mimetic seed hypothesis. On the other hand, the rates of disappearance of seeds from the ground under the Ormosia trees, hardness of the seeds, and enhancement of germination with the abrasion of the seed coat are all consistent with the hard-seed for grit hypothesis. RESUMEN. Semillas con arilos falsos aparecen estar cubiertas en parte o completamente por pulpa o arilo, pero en realidad no llevan ninguna materia carnosa. El hipótesis semilla mímica propone que las semillas parecen frutos carnosos cuyas semillas están dispersadas por aves y que engañan las aves a dispersar sus semillas sin recibir una recompensa nutritiva — una relación parasítica. El hipótesis semilla dura para arenisca propone que aves grandes y terrestres tragan las semillas mímicas y excepcionalmente duras como arenisca para moler las semillas más suaves en que se alimentan; las aves defecan y dispersan las semillas, y las rascan, lo cual mejora la germinación — una relación mutua. Cualquier mimetismo es incidente. Se observaron árboles de Ormosia espp. (Leguminosae: Papilionoideae) con frutos para averiguar los mecanismos de dispersión de semillas y el papel que hacen las características aparentemente mímicas de sus semillas en esa dispersión. Se examinaron también la depredación y germinación de semillas. Las semillas mímicas de Ormosia isthamensis y O. macrocalyx (pero no O. bopiensis), engañaron aves frugivoras y arbóreas en comerlas, aunque las tasas de dispersión eran bajas. Estos resultados son consistente con el hipótesis semilla mímica. En cambio, las tasas de desaparición de semillas caídas de Ormosia, dureza de las semillas, y mejoramiento de germinación con la raedura de las capas de las semillas son consistente con el hipótesis semilla dura para arenisca.
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James, Trevor K., Michael R. Trolove, and Claire A. Dowsett. "Roadside mowing spreads yellow bristle grass (Setaria pumila) seeds further than by natural dispersal." New Zealand Plant Protection 72 (July 22, 2019): 153–57. http://dx.doi.org/10.30843/nzpp.2019.72.246.
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Yellow bristle grass is a highly invasive annual C4 pasture weed that has spread rapidly through many New Zealand dairying regions via seed dispersal. Seven trials were conducted on roadsides infested with yellow bristle grass to evaluate natural and mower-assisted dispersal. To trap seeds, yellow sticky traps were laid out at various intervals both perpendicular to and parallel to the road. Traps were in place for 24 h in the four natural dispersal trials but only for the event in the mowing trials. Seeds on the retrieved traps were counted and the seeds caught in the mower estimated. For natural dispersal, 90% of seeds fell within 0.5 m. When mown, 90% of the seeds fell within 2 metres in the direction of mowing and 80% within 20 cm in the perpendicular direction. More importantly, a small percentage of dispersed seeds were caught in the mower and presumably could subsequently fall off anywhere. Mowing mature yellow bristle grass on the roadside will result in accelerating seed dispersal along the roadside for many metres and potentially many kilometres.
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Dwi Atmanto, Andrian, Bainah Sari Dewi, and Nuning Nurcahyani. "Peran Siamang (Hylobates Syndactylus) Sebagai Pemencar Biji Di Resort Way Kanan Taman Nasional Way Kambas Lampung." Jurnal Sylva Lestari 2, no. 1 (April 4, 2014): 49. http://dx.doi.org/10.23960/jsl1249-58.
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Way Kambas National Parklocated inLampung Provinceis habitat for gibbon (H. syndactylus), frugivorous primate which plays a role as seeds dispersal process in tropical rainforests with its activities. Purpose of the research is to determine the gibbon’s role as seeds dispersal. It was conducted in August 2012 in the Way Kanan Resort of Way Kambas National Park. The method used is exploration and feces analysis.Based on the research, there are 37 samples of gibbon’s feces and 7 spesies of seed plant dispersed by gibbon include Polygonum chinense, Grewia paniculata,Ficus sp, Bouea macrophylla,Dacryodes rostrata, Aporosa aurita, and Aplaia palembanica.Seeds are distributed by gibbon using endozoochory process without destroying seeds and can be dispersed far from the parent trees.Distance of the seed dispersed by gibbons ranges 0−385 meters. Defecation activity of gibbon is done after waking,feeding activity, and when moved to other tree with frequency of defecation between 3−6 times a day. The composition ofgibbon’s feces is seeds and leaves. The highest attendance of seeds in feces is Polygonum chinense seeds (42,12%) and the lowest is Aporosa aurita seeds (1,18%). The mean seeds in feces is7,38 from 273 seeds. Key words : gibbon, seed dispersal, Way Kambas National Park
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Coates-Estrada, Rosamond, and Alejandro Estrada. "Frugivory and seed dispersal in Cymbopetalum baillonii (Annonaceae) at Los Tuxtlas, Mexico." Journal of Tropical Ecology 4, no. 2 (May 1988): 157–72. http://dx.doi.org/10.1017/s0266467400002650.
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ABSTRACTFruit production, frugivore foraging activity and seed dispersal was studied at 10 Cymbopetalum baillonii (Annonaceae) trees during an entire fruiting season. Fruits dehisced during the first six months of the year offer to potential dispersal agents a package of 8–24 arillate seeds. Insects and fungi, however, killed up to 14% of the seeds potentially available for dispersal before fruit dehiscence. Visitation by 24 species of birds and one mammal to the trees closely followed the availability of arillate seeds. The foraging activity of Peromyscus and Heteromys rodents accounted for ≥ 80% mortality of the seeds deposited under the crown of the parent tree. Among those seedlings that became established under the crown mortality was ≥ 90% after 12 months. Seeds dispersed under conspecific fruiting trees experienced intense predation by vertebrates. Field experiments showed that seeds and seedlings planted ≥ 30 m away from adult trees survived significantly longer than those planted under the crown and at distances ≤ 30 m. An unequivocal advantage to dispersal away from the tree and under allospecific trees was evident from the data. A very narrow range of frugivores (N = 8 species) accounted for the quality component of dispersal services to the trees. The tree with the lowest animal visitation and fruit crop was the most efficient in the dispersal of its seeds.
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Shirtliffe, Steven J., and Martin H. Entz. "Chaff collection reduces seed dispersal of wild oat (Avena fatua) by a combine harvester." Weed Science 53, no. 4 (August 2005): 465–70. http://dx.doi.org/10.1614/ws-03-109r2.
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Combine harvesters have the potential to disperse weed seeds great distances. Reducing this dispersal may be important in an integrated weed management system. The objectives of this study were to determine the distance that wild oat seeds are dispersed by a combine harvester and the effect of chaff collection on combine harvester seed dispersal. This was measured by sampling wild oat seeds at varying distances behind a combine equipped with a removable chaff collection system after it passed through a wild oat patch. Chaff collection consistently reduced the amount and distance that wild oat seeds were dispersed. This occurred because more than 74% of the total wild oat seed that were ejected from the combine were in the chaff. Because most of the chaff falls in a row directly behind the combine, chaff collection only affected dispersal in this area. In 1996, chaff collection reduced wild oat seed dispersal past the wild oat patch to less than 10 seeds m−2at 45 m, whereas without chaff collection, there was greater than 10 seeds m−2up to 145 m. At distances beyond 145 m, chaff collection had no significant effect on seed dispersal. Chaff collection may be an important tool in an integrated weed management program because it may slow weed invasions and reduce the expansion of weed patches.
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Peña-Domene, Marinés, Cristina Martínez-Garza, Luz Ayestarán-Hernández, and Henry Howe. "Plant Attributes that Drive Dispersal and Establishment Limitation in Tropical Agricultural Landscapes." Forests 9, no. 10 (October 10, 2018): 620. http://dx.doi.org/10.3390/f9100620.
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Factors that influence tropical-forest regeneration have been of interest across the tropics. We tested the degree of dispersal and establishment limitation of pioneer and non-pioneer tree species with different dispersal modes and seed sizes, using data on both seed fall and seedling establishment in primary forest, secondary forest, and pasture excluded from livestock. The study took place in a lowland tropical rain forest in southeastern Mexico. To calculate dispersal and establishment limitation, we used a density-weighted index that considers: (1) whether a seed or seedling of a given species has arrived in the sample area; and (2) the fraction of seeds or seedlings contributed by a given species relative to the total number of seeds or seedlings arriving at a sampling station. Dispersal limitation of non-pioneer species and animal-dispersed species decreased with succession. The secondary forest had less dispersal limitation for wind-dispersed pioneers than pasture, resulting in a dense aggregation of species with seeds dispersed by wind. Overall, establishment limitation differed between animal-dispersed and wind-dispersed species in the primary forest, and was negatively correlated with seed size. The low capacity of most species to arrive, germinate, and establish as seedlings in pastures slows succession back to forest. To overcome barriers to natural succession in pastures, transplanting seedlings of non-pioneer species is suggested because most of them show high dispersal and establishment limitation.
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Heleno, Ruben H., Jens M. Olesen, Manuel Nogales, Pablo Vargas, and Anna Traveset. "Seed dispersal networks in the Galápagos and the consequences of alien plant invasions." Proceedings of the Royal Society B: Biological Sciences 280, no. 1750 (January 7, 2013): 20122112. http://dx.doi.org/10.1098/rspb.2012.2112.
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Alien plants are a growing threat to the Galápagos unique biota. We evaluated the impact of alien plants on eight seed dispersal networks from two islands of the archipelago. Nearly 10 000 intact seeds from 58 species were recovered from the droppings of 18 bird and reptile dispersers. The most dispersed invaders were Lantana camara , Rubus niveus and Psidium guajava , the latter two likely benefiting from an asynchronous fruit production with most native plants, which facilitate their consumption and spread. Lava lizards dispersed the seeds of 27 species, being the most important dispersers, followed by small ground finch, two mockingbirds, the giant tortoise and two insectivorous birds. Most animals dispersed alien seeds, but these formed a relatively small proportion of the interactions. Nevertheless, the integration of aliens was higher in the island that has been invaded for longest, suggesting a time-lag between alien plant introductions and their impacts on seed dispersal networks. Alien plants become more specialized with advancing invasion, favouring more simplified plant and disperser communities. However, only habitat type significantly affected the overall network structure. Alien plants were dispersed via two pathways: dry-fruited plants were preferentially dispersed by finches, while fleshy fruited species were mostly dispersed by other birds and reptiles.
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Perry, George L. W. "How far might plant-eating dinosaurs have moved seeds?" Biology Letters 17, no. 1 (January 2021): 20200689. http://dx.doi.org/10.1098/rsbl.2020.0689.
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Fossilized gut contents suggest that seeds consumed by dinosaurs may have remained intact in their stomachs, and since seed dispersal distance increases with body-mass in extant vertebrates, dinosaurs may have moved seeds long distances. I simulated seed dispersal by dinosaurs across body-masses from 1 × 10 1 to 8 × 10 4 kg using allometric random walk models, informed by relationships between (i) body-mass and movement speed, and (ii) body-mass and seed retention time. Seed dispersal distances showed a hump-shaped relationship with body-mass, reflecting the allometric relationship between maximum movement speed and body-mass. Across a range of assumptions and parameterizations, the simulations suggest that plant-eating dinosaurs could have dispersed seeds long distances.
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Dellafiore, C. M., J. B. Gallego-Fernández, and S. Muñoz Vallés. "The Contribution of Endozoochory to the Colonization and Vegetation Composition of Recently Formed Sand Coastal Dunes." Research Letters in Ecology 2007 (2007): 1–3. http://dx.doi.org/10.1155/2007/74090.
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The objective of this study was to determine whether endozoochory contributes to the dispersal and colonization of plant species in recently formed coastal dunes. At least 5.7% of species present in the study area are being dispersed by wild rabbits (Oryctolagus cuniculusL.). Most dispersed species are perennial herbs with small seeds size. The continuous input of seeds through rabbit feces into newly created areas would ensure the constant arrival of seeds and would facilitate colonization. Therefore, endozoochorous dispersal may play a relevant role for the structure and composition of dune plant communities.
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Gibson, Robert. "Hypothesis of tumbleweed-like dispersal of Drosera seeds." Carnivorous Plant Newsletter 49, no. 4 (December 1, 2020): 181–82. http://dx.doi.org/10.55360/cpn494.rg377.
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Erect-growing tuberous sundews of Drosera subgenus Ergaleium section Ergaleium produce seeds of diverse size and shape. Seeds produced by such species as D. andersoniana, D. macrantha, and D. pallida are large and winged, and fit the classic model of those dispersed by the wind. However, many species in this section produce small, round seeds (e.g. D. gigantea, D. salina, and D. yilgarnensis) that appear better suited to dispersal by gravity or water than by the wind. I propose here, that long-distance dispersal of these species may also be facilitated by the transport of detached plant parts, with seed, by the wind.
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Webb, Sara L. "Potential Role of Passenger Pigeons and Other Vertebrates in the Rapid Holocene Migrations of Nut Trees." Quaternary Research 26, no. 3 (November 1986): 367–75. http://dx.doi.org/10.1016/0033-5894(86)90096-7.
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Rapid rates of species range extension during the Holocene represent seed dispersal distances of at least 6 to 8 km per generation for North American species of Fagus, Quercus, and Carya, taxa whose fruits are heavy nuts. Occasional seed dispersal by biotic seed predators is necessary for these dispersal distances. One likely agent for dispersal across long distances and habitat discontinuities was the extinct (since 1914 A.D.) passenger pigeon (Ectopistes migratorius). This bird's abundance, capacity for delayed digestion, and nomadic habits strongly suggest an occasional seed dispersal role, although a coevolutionary seed dispersal relationship cannot be inferred from available evidence. The capacity of some heavy seeds for dispersal distances greater than those of most light, wind-dispersed seeds has biogeographic and genetic implications.
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Estrada, Alejandro, and Rosamond Coates-Estrada. "Howler monkeys (Alouatta palliata), dung beetles (Scarabaeidae) and seed dispersal: ecological interactions in the tropical rain forest of Los Tuxtlas, Mexico." Journal of Tropical Ecology 7, no. 4 (November 1991): 459–74. http://dx.doi.org/10.1017/s026646740000585x.
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ABSTRACTThe dispersal of seeds by howler monkeys (Alouatta palliata) and the activity of dung beetles in modulating the fate of the dispersed seed were studied at Los Tuxtlas, Mexico. Howlers consumed the fruits of 35 species of plants. The seeds of 28 of these were dispersed by the monkeys. The majority (≥90%) of the seeds dispersed by monkeys were destroyed by rodents. Rapid relocation and burial of dung by dung beetles resulted in accidental relocation and burial of large numbers of seeds shortly after deposition. Faecal clumps (20 mg) remained on the ground for an average of only 2.5 h (range 1–3 h). Ball rolling beetles transported balls up to 5.0 m from the site of deposition (range 1–5 m). Burrowing and ball-rolling dung beetles buried seeds at depths ranging from 2.5 to > 12.0cm. The deeper a seed is buried, the less likely it is to be found and eaten by rodents. Eighty percent of the species used by Alouatta as sources of fruit at Los Tuxtlas benefited by the dispersal and post dispersal service provided by howlers and dung beetles respectively. Seasonality in dung beetles abundance in the forest may influence the number of seeds per species escaping post-dispersal predation during the year. Dung beetles play not only an important ecological role in the recycling of matter and energy in the ecosystem, but also in the process of rain forest regeneration.
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O'Farrill, Georgina, Colin A. Chapman, and Andrew Gonzalez. "Origin and deposition sites influence seed germination and seedling survival of Manilkara zapota: implications for long-distance, animal-mediated seed dispersal." Seed Science Research 21, no. 4 (August 5, 2011): 305–13. http://dx.doi.org/10.1017/s0960258511000201.
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AbstractThe distribution and dynamics of plant populations depend on the recruitment of young individuals, which is influenced by seed production, animal seed dispersal, dispersal distance, and the deposition of seeds in favourable places for seed germination/establishment and seedling survival. In particular, seeds dispersed over long distances will likely encounter new environmental conditions that occur at large spatial scales, with seed and seedling survival influenced by the adaptation of plant populations to soil and climate conditions. In this paper, it is hypothesized that seed germination and seedling survival probabilities depend on seed origin and deposition sites. A reciprocal seed and seedling transplant experiment was carried out with zapote seeds (Manilkara zapota) to determine the effect of origin and deposition sites on seed germination and seedling survival over a year in the Greater Calakmul Region of Mexico. Two origin and two deposition sites were selected that show different soil moisture levels within the habitat of the Baird's tapir, a major seed disperser of M. zapota seeds. The results show that sites of origin and deposition influenced seed germination and seedling survival probabilities. This suggests that the displacement of seeds far from parent trees, while potentially reducing intraspecific competition, does not ensure their survival, and that seeds need to be deposited in microsites within their environmental tolerance for dispersal to be successful. Furthermore, this paper emphasizes the importance of field experiments to provide strong inference about the effects of environmental conditions on recruitment and distribution of plant species.
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Malo, Juan E. "Potential ballistic dispersal of Cytisus scoparius (Fabaceae) seeds." Australian Journal of Botany 52, no. 5 (2004): 653. http://dx.doi.org/10.1071/bt03162.
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Cytisus scoparius (L.) Link (Fabaceae) has a ballistic type of primary seed-dispersal mechanism in which its legumes dehisce suddenly when they dry. This paper presents an experimental approach to the measurement and modeling of distances reached by seeds under optimum dispersal conditions. Branchlets of the species carrying mature legumes were collected and attached to 1.20-m-high platforms on a flat roof terrace. For 2 weeks, daily measurements were made of distances attained by seeds ejected from legumes in the previous 24 h. Seeds were found at a distance of 2343 ± 113 mm (mean ± s.e., n = 245), with 10.2% of recorded distances greater than 5 m and some about 7 m. The mixture model fitted to the distances traveled by seeds allows the mathematical isolation of two underlying processes, the ballistic projection of seeds by dehiscent legumes (nearly 49% of seeds, reaching 3686 ± 1797 mm) and the barochorous dispersal of the remaining seeds in the platform environs (1254 ± 1254 mm). Modeling shows that seeds dispersed ballistically reach locations at some distance from the shrub crown, with low densities of sibling seeds—a potential advantage for the establishment of new individuals.
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del Castillo, R. F., and M. A. Pérez Ríos. "Changes in seed rain during secondary succession in a tropical montane cloud forest region in Oaxaca, Mexico." Journal of Tropical Ecology 24, no. 4 (July 2008): 433–44. http://dx.doi.org/10.1017/s0266467408005142.
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AbstractSeed dispersal is the first stage of colonization, and potentially affects recruitment. This process deserves more attention in tropical montane cloud forests (TMCF), since secondary succession is common owing to episodic disturbances. We studied annual seed rain in 10 nearby forest stands, ≈7 to ≈100 y following shifting agriculture, and one primary forest stand in southern Mexico to test the hypothesis that seed rain is limited at the scale of neighbouring fragments and that such limitation differs among species with different dispersal modes and successional origin. Annual seed rain was heterogeneous among forest fragments probably due to the prevalence of local seed dispersal, differences in stand age and the proportion of zoochory, and may help explain the patchy distribution of species observed in TMCF. Seed rain abundance and species diversity per unit trap area increased with the age of the stand. Biotically dispersed seeds increased towards older stands relative to abiotically dispersed seeds. Late-successional seeds were rarer in early successional stands than pioneer seeds in late-successional stands, suggesting that long-distance dispersal is generally more common for pioneer plants. Seed dispersal appears to constrain forest regeneration and to influence fragment species composition as a function of the distance from the source forests.
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Haurez, Barbara, Kasso Daïnou, Nikki Tagg, Charles-Albert Petre, and Jean-Louis Doucet. "The role of great apes in seed dispersal of the tropical forest tree species Dacryodes normandii (Burseraceae) in Gabon." Journal of Tropical Ecology 31, no. 5 (July 29, 2015): 395–402. http://dx.doi.org/10.1017/s0266467415000322.
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Abstract:The identification of seed dispersers and predators is essential to understand the effect of anthropogenic disturbances, and the associated defaunation process, on tropical forest dynamics in Central Africa. In this study, the animals involved in seed predation and dispersal of Dacryodes normandii (Burseraceae), an endozoochorously dispersed tree species endemic to Gabonese forests, were identified in a site in south-east Gabon using two complementary methods: direct observation and camera-trap monitoring of fruit piles. The combined sampling effort (172 h of direct observations and 796 d of camera trapping) led to the identification of six disperser and eight predator species of D. normandii seeds. With high frequency of consumption (88% and 57% of their visits, respectively) and long visit duration (83 and 23 min, respectively), the western lowland gorilla and central chimpanzee were identified as the main dispersers of this species. Seeds passed through the gorilla gut exhibited high germination success (68%). Rodents were identified as predators of D. normandii seeds, potentially displaying rare secondary dispersal through scatter-hoarding. The results of this study highlight the importance of great apes in the seed dispersal of this tree species.
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Valdesolo, Tommaso, Silvia Del Vecchio, and Gabriella Buffa. "Patterns of Seed Dispersal in Coastal Dune Plant Communities." Sustainability 14, no. 17 (September 2, 2022): 10983. http://dx.doi.org/10.3390/su141710983.
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Seed dispersal is a key determinant of species distribution, although it is still unclear how it contributes to species assembly in plant communities. We linked patterns of seed dispersal to coexisting species to investigate the role of dispersal in the species assembly process. We focused on 19 species coexisting in a foredune plant community, classified as “foredune foundation species”, “semi-fixed dune species,” and “alien species”. The number of seeds dispersed by the 19 species was monitored monthly in 25 plots for 12 months. Then we compared both dispersal strategies and dispersal phenology among the species. Foredune foundation species, species of the semi-fixed dune, and alien species used the same dispersal strategies, with the exception of hemerochory, which was prevalently used by alien species. The three groups of species differentiated the dispersal season: semi-fixed dune species and alien species were early and late dispersers, respectively (spring vs. late summer), while foredune foundation species dispersed seeds in summer. Seasonal differentiation in seed dispersal may play a more important role in the species assembly process than dispersal vectors. Shifts in seasonality due to climate change may influence the timing of seed dispersal and provide species with different colonization opportunities.
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Wrangham, Richard W., Colin A. Chapman, and Lauren J. Chapman. "Seed dispersal by forest chimpanzees in Uganda." Journal of Tropical Ecology 10, no. 3 (August 1994): 355–68. http://dx.doi.org/10.1017/s0266467400008026.
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ABSTRACTThe role of chimpanzees (Pan troglodytes) as seed dispersers in the Kibale Forest Reserve of western Uganda was assessed by analysing 1849 dung samples from two chimpanzee communities and by conducting germination trials on dispersed and non-dispersed seeds. Of the chimpanzee dung samples, 98.5% contained seeds, and fig seeds were the most common. The number of large seeds (>2 mm) per dung sample was often high, even for species with a relatively large seed. For example, Mimusops bagshawei has a 15-mm diameter seed and had an average of 26.5 seeds per sample. In addition, many seed species were found in the dung repeatedly over several months. Germination trials demonstrated that the species of seed commonly collected from dung were viable. Comparisons of both the rate and success of germination of chimpanzee-dispersed seeds with seeds collected directly from the parent trees, showed that gut passage increased the speed and probability of germination. The number of large seeds dispersed by the chimpanzee population was estimated at 369 large seeds km-1 day-1. We suggest that in Kibale, chimpanzees may play a more significant role in primary seed dispersal than implied by their low numbers and biomass.
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Hammill, K. A., R. A. Bradstock, and W. G. Allaway. "Post-fire Seed Dispersal and Species Re-establishment in Proteaceous Heath." Australian Journal of Botany 46, no. 4 (1998): 407. http://dx.doi.org/10.1071/bt96116.
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Aspects of seed dispersal of five functionally similar, serotinous species, Banksia serrata L.f., B. ericifolia L.f., B. marginata Cav., Hakea sericea Schrader, and H. teretifolia (Salisb.) Britten (Proteaceae), from coastal heath near Sydney were investigated. These species have seeds with large papery wings apparently suited to dispersal by wind. Terminal falling velocities of seeds of all species were close to 1 m s-1 despite significant differences in seed sizes and wing loadings. Patterns of aerial dispersal of seeds in a wind tunnel and in a burnt heath site were also similar among species, with seeds dispersed up to 12 m. Seeds were also dispersed along a sandy substrate in burnt heath distances of up to 3 m in 1 h under windy conditions. A survey of post-fire seedling distribution relative to a seed source found seedling density to be highest in and near seed sources, decreasing loge–linearly with distance from the source up to 40 m. The similarity between distances of seed dispersal determined experimentally and patterns of in situ seedlings relative to a seed source led to the conclusion that wind dispersal of seed is the major determinant of seedling patterns after fire. Recolonisation of areas of local extinction of species following high fire frequency is likely to occur at the rate of a few tens of metres after each successive fire providing that plants have matured during the inter-fire period.
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Baião, Sirley A. A., Fernanda B. A. Correia, and Stephen F. Ferrari. "Dietary differences have contrasting effects on the seed dispersal potential of the titi monkey Callicebus coimbrai in north-eastern Brazil." Journal of Tropical Ecology 31, no. 2 (November 28, 2014): 175–81. http://dx.doi.org/10.1017/s0266467414000649.
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Abstract:Gut transit times and dispersal distances of seeds ingested by Callicebus coimbrai at two localities were estimated by tracing seeds found in faeces to feeding sites. Feeding events and faecal samples were recorded/collected and mapped by GPS between April and July, 2012. Junco group fed almost exclusively on fruit, whereas Trapsa group fed on fruit and leaves/flowers in similar proportions. A much higher proportion of faecal samples from Junco contained seeds (47.9%, n = 244, vs. 33.6%, n = 177), and contained more seeds, on average (3.0 ± 2.8 vs. 2.1 ± 2.1) than those from Trapsa. However, gut transit times were absolutely longer at Trapsa (mean = 4.87 ± 1.48 h, n = 6, vs. 2.85 ± 0.53 h, n = 13 daytime events), and dispersal distances were significantly longer (200 ± 81.0 m vs. 126 ± 53.4 m). The evidence indicates that, while the more folivorous diet at Trapsa was reflected in a much lower faecal seed count, it was also associated with longer gut transit times, and significantly longer dispersal distances, i.e. while dispersing approximately half the seeds dispersed by Junco group, Trapsa group dispersed these seeds over almost twice the distance.
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de Barros Leite, Abraão, Pedro H. S. Brancalion, Roger Guevara, and Mauro Galetti. "Differential seed germination of a keystone palm (Euterpe edulis) dispersed by avian frugivores." Journal of Tropical Ecology 28, no. 6 (November 2012): 615–18. http://dx.doi.org/10.1017/s0266467412000594.
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The effectiveness of seed dispersal by vertebrates has been analysed by examining both quantitative and qualitative components (Jordano & Schupp 2000, Schupp et al. 2010). While the quantitative component is relatively easily assessed in the field (e.g. visitation rate, number of fruits eaten per visit), the qualitative component (e.g. fate of dispersed seeds, seed treatment in the digestive system of the disperser) is rarely studied under natural conditions, because it is difficult to measure the effects on seeds once ingested by the dispersers (Cortes et al. 2009).
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Loebach, Christopher A., and Roger C. Anderson. "Measuring short distance dispersal of Alliaria petiolata and determining potential long distance dispersal mechanisms." PeerJ 6 (March 15, 2018): e4477. http://dx.doi.org/10.7717/peerj.4477.
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Introduction Alliaria petiolata, an herbaceous plant, has invaded woodlands in North America. Its ecology has been thoroughly studied, but an overlooked aspect of its biology is seed dispersal distances and mechanisms. We measured seed dispersal distances in the field and tested if epizoochory is a potential mechanism for long-distance seed dispersal. Methods Dispersal distances were measured by placing seed traps in a sector design around three seed point sources, which consisted of 15 second-year plants transplanted within a 0.25 m radius circle. Traps were placed at intervals ranging from 0.25–3.25 m from the point source. Traps remained in the field until a majority of seeds were dispersed. Eight probability density functions were fitted to seed trap counts via maximum likelihood. Epizoochory was tested as a potential seed dispersal mechanism for A. petiolata through a combination of field and laboratory experiments. To test if small mammals transport A. petiolata seeds in their fur, experimental blocks were placed around dense A. petiolata patches. Each block contained a mammal inclusion treatment (MIT) and control. The MIT consisted of a wood-frame (31 × 61× 31 cm) covered in wire mesh, except for the two 31 × 31 cm ends, placed over a germination tray filled with potting soil. A pan filled with bait was placed in the center of the tray. The control frame (11 × 31 × 61 cm) was placed over a germination tray and completely covered in wire mesh to exclude animal activity. Treatments were in the field for peak seed dispersal. In March, trays were moved to a greenhouse and A. petiolata seedlings were counted and then compared between treatments. To determine if A. petiolata seeds attach to raccoon (Procyon lotor) and white-tailed deer (Odocoileus virginianus) fur, wet and dry seeds were dropped onto wet and dry fur. Furs were rotated 180 degrees and the seeds that remained attached were counted. To measure seed retention, seeds were dropped on furs and rotated as before, then the furs were agitated for one hour. The seeds retained in the fur were counted. Results For the seed dispersal experiment, the 2Dt function provided the best fit and was the most biologically meaningful. It predicted that seed density rapidly declined with distance from the point source. Mean dispersal distance was 0.52 m and 95% of seeds dispersed within 1.14 m. The epizoochory field experiment showed increased mammal activity and A. petiolata seedlings in germination trays of the MIT compared to control. Laboratory studies showed 3–26% of seeds were attached and retained by raccoon and deer fur. Retention significantly increased if either seed or fur were wet (57–98%). Discussion Without animal seed vectors, most seeds fall within a short distance of the seed source; however, long distance dispersal may be accomplished by epizoochory. Our data are consistent with A. petiolata’s widespread distribution and development of dense clusters of the species in invaded areas.
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Egawa, Chika, Atsushi Shoji, and Hiroyuki Shibaike. "Wind-mediated seed dispersal of invasive forage grasses from agricultural grasslands in Hokkaido, Japan." Invasive Plant Science and Management 12, no. 02 (May 28, 2019): 133–41. http://dx.doi.org/10.1017/inp.2019.11.
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AbstractAlthough introduced pasture grasses are essential for forage production in current livestock farming, some species cause serious impacts on native biodiversity when naturalized. Information on the seed dispersal of invasive forage grasses from cultivated settings to surrounding environments can inform management efforts to prevent their naturalization. In this case study, we quantified the wind-mediated seed dispersal distance and amount of dispersed seed of invasive forage grasses from agricultural grasslands in Hokkaido, northern Japan. In total, 200 funnel seed traps were installed around three regularly mown grasslands and one unmown grassland where various forage grass species were grown in mixture. Seeds of each species dispersed outside the grasslands were captured from May to October 2017. Based on the trapped distances of seeds, the 99th percentile dispersal distance from the grasslands was estimated for six species, including timothy (Phleum pratense L.), orchardgrass (Dactylis glomerata L.), and Kentucky bluegrass (Poa pratensis L.). For two dominant species, P. pratense and D. glomerata, the numbers of seeds dispersed outside the field under mown and unmown conditions were determined under various plant cover situations. The estimated dispersal distances ranged from 2.3 m (P. pratense) to 31.5 m (P. pratensis), suggesting that areas within approximately 32 m of the grasslands are exposed to the invasion risk of some forage grass species. For both P. pratense and D. glomerata, the number of seeds dispersed outside the unmown grassland exceeded 100 seeds m−2 under high plant cover situations, while the number of seeds dispersed from the mown grasslands at the same plant cover level was less than one-third of that number. The results suggest that local land managers focus their efforts on frequent mowing of grasslands and monitoring of the areas within approximately 32 m of the grasslands to substantially reduce the naturalization of invasive forage grasses.
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Rehm, E., E. Fricke, J. Bender, J. Savidge, and H. Rogers. "Animal movement drives variation in seed dispersal distance in a plant–animal network." Proceedings of the Royal Society B: Biological Sciences 286, no. 1894 (January 16, 2019): 20182007. http://dx.doi.org/10.1098/rspb.2018.2007.
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Frugivores play differing roles in shaping dispersal patterns yet seed dispersal distance is rarely quantified across entire communities. We model seed dispersal distance using gut passage times and bird movement for the majority (39 interactions) of known bird–tree interactions on the island of Saipan to highlight differences in seed dispersal distances provided by the five avian frugivores. One bird species was found to be a seed predator rather than a disperser. The remaining four avian species dispersed seeds but differences in seed dispersal distance were largely driven by interspecific variation in bird movement rather than intraspecific variation in gut passage times. The median dispersal distance was at least 56 m for all species-specific combinations, indicating all species play a role in reducing high seed mortality under the parent tree. However, one species—the Micronesian Starling—performed 94% of dispersal events greater than 500 m, suggesting this species could be a key driver of long-distance dispersal services (e.g. linking populations, colonizing new areas). Assessing variation in dispersal patterns across this network highlights key sources of variation in seed dispersal distances and suggests which empirical approaches are sufficient for modelling how seed dispersal mutualisms affect populations and communities.
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Yager, Lisa Y., Deborah L. Miller, and Jeanne Jones. "Woody Shrubs as a Barrier to Invasion by Cogongrass (Imperata cylindrica)." Invasive Plant Science and Management 4, no. 2 (April 2011): 207–11. http://dx.doi.org/10.1614/ipsm-d-10-00052.1.
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AbstractCogongrass invades forests through rhizomatous growth and wind-dispersed seeds. Increased density and abundance of woody vegetation along forest edges may strengthen biotic resistance to invasion by creating a vegetative barrier to dispersal, growth, or establishment of cogongrass. We evaluated differences in dispersal of cogongrass spikelets experimentally released from road edges into tallgrass-dominated and shrub-encroached longleaf pine forests (Pinus palustris). Average maximum dispersal distances were greater in the pine–tallgrass forest (17.3 m) compared to the pine–shrub forest association (9.4 m). Spikelets were more likely to be intercepted by vegetation in pine–shrub forests compared to pine–tallgrass forests. Results suggest that dense woody vegetation along forest edges will slow spread from wind-dispersed cogongrass seeds.
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Taghizadeh, M. S., M. E. Nicolas, and R. D. Cousens. "Effects of relative emergence time and water deficit on the timing of fruit dispersal in Raphanus raphanistrum L." Crop and Pasture Science 63, no. 10 (2012): 1018. http://dx.doi.org/10.1071/cp12246.
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Seed dispersal is both a spatial and a temporal phenomenon, although most studies focus on spatial aspects. Seed initiation on the maternal plant may occur over a considerable period, especially in indeterminately flowering species, and thus seeds may be exposed to a wide range of environmental conditions during their development. The result is variation in the timing of seed development, the anatomy of structures related to the dispersal process, and the behaviour and fate of seeds post-dispersal. A key resource during the growth and development of summer-maturing species in most areas, and one that is thus likely to modify these processes, is water. Two experiments were therefore undertaken to describe (i) the development of Raphanus raphanistrum fruits and the timing of fruit dispersal, and (ii) the effects of water availability on the timing of fruit dispersal. Fewer seeds were produced and subsequently dispersed by later emerging plants. The duration of fruit dispersal became shorter when the plants emerged progressively later than the crop, and the time of maximum dispersal was later. For cohorts of fruits initiated at the same time, those that developed under mild and severe water deficit reached their final length sooner, and were dispersed sooner, than those receiving a plentiful supply of water. Thus, the phenology of the maternal plant and the nature of its environment can modify the timing of propagule maturity and consequently dispersal. Such information may provide an opportunity for managers to reduce weed seed return to their field or, conversely, to regulate the amount of contaminated grain or reduce dispersal to other locations.
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Galindo-González, Jorge, Guillermo Vázquez-Domínguez, Romeo A. Saldaña-Vázquez, and Jesús R. Hernández-Montero. "A more efficient technique to collect seeds dispersed by bats." Journal of Tropical Ecology 25, no. 2 (March 2009): 205–9. http://dx.doi.org/10.1017/s0266467409005859.
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Seeds dispersed and deposited by wind, animals and other dispersal agents are a fundamental component of natural forest succession, plant regeneration and population maintenance, aside from increasing a population's genetic pool in tropical ecosystems (Henry & Jouard 2007, Muscarella & Fleming 2007, Wilson & Traveset 2000). Frugivorous bats and birds are ideal vectors for long-distance seed dispersal; therefore, studies of the food habits of frugivores and the specific identities of the dispersers are essential for understanding ecological patterns and processes in tropical environments. Studies related to succession processes, the frequency, number and composition of seeds dispersed by animals are essential in order to generate new data and hypotheses, consequently the method and quality of obtaining data are important.
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McConkey, Kim R., and David J. Chivers. "Influence of gibbon ranging patterns on seed dispersal distance and deposition site in a Bornean forest." Journal of Tropical Ecology 23, no. 3 (April 24, 2007): 269–75. http://dx.doi.org/10.1017/s0266467407003999.
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Frugivores display daily and seasonal behavioural variation, yet the influence of this variability on subsequent seed shadows is rarely considered. We investigated the extent to which three aspects of gibbon (Hylobates muelleri × agilis) foraging and ranging behaviour (revisitation of favoured fruit sources, daily and monthly ranging patterns) influenced seed dispersal distances and deposition sites for two groups in dipterocarp forests at the Barito Ulu research site, Kalimantan, Indonesia. Dispersal distances and sites were estimated using gut retention times and ranging patterns collected over 12 mo. Gibbons dispersed few seeds (0.7%) under parent trees and most seeds (> 90%) were dispersed more than 100 m. Mean dispersal distances differed significantly between groups (339 m and 431 m) and across different months. Deposition site was only influenced by time of day, with all seeds swallowed in the first hour of activity being deposited under sleeping trees used that night. Both groups visited all 0.25-ha quadrats within their home range over the study period, indicating that gibbons potentially disperse seeds throughout their home range. Given the general uniformity of the gibbon seed shadow, the intensity of home range use and large seed dispersal distances, gibbons appear to be consistently effective seed dispersers and are probably one of the most important frugivores in Asian rain forests.
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Nie, Shenghong, Lizhi Zhou, and Wenbin Xu. "Effect of Seed Traits and Waterbird Species on the Dispersal Effectiveness of Wetland Plants." Biology 11, no. 5 (April 20, 2022): 629. http://dx.doi.org/10.3390/biology11050629.
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Seed dispersal is an important ecological process in wetland ecosystems and helps maintain community structure and ecosystem biodiversity. Waterbird-mediated endozoochory is an effective and feasible dispersal mechanism for wetland plants; however, the influence of vectors and seed traits on this mechanism remains unclear. To investigate the effects of vector species and seed traits (length and lignin) on retention time, retrieval and germination of gut-surviving seeds, we fed Baikal teals (Anas formosa) and green-winged teals (Anas crecca) eight common plant seeds (Polygonum aviculare, Rumex dentatus, Polygonum orientale, Vallisneria natans, Ranunculus polii, Polygonum hydropiper, Carex cinerascen and Euphrasia pectinata) in the Shengjin Lake wetland (a Ramsar site). We collected fecal samples at intervals of 2–6 h for 36 h, and found that the percentage of recovered seeds differed significantly among teal and plant species (3%~30%); 94% of viable seeds were recovered within 12 h after feeding. Moreover, the germination rate of the recovered seeds (25%~56%) was higher than that of the control. The seed retention time was affected by seed lignin and disperser species; higher lignin made digestion difficult with higher retrieval. Smaller seeds passed through the guts but had no significant effect on recovered seeds. Seed length and disperser species showed no significant correlation with germination. These findings suggested endozoochory by dabbling ducks as an effective wetland seed dispersal mechanism.
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Kitamura, Shumpei, Shunsuke Suzuki, Takakazu Yumoto, Pilai Poonswad, Phitaya Chuailua, Kamol Plongmai, Naohiko Noma, Tamaki Maruhashi, and Chumphon Suckasam. "Dispersal of Aglaia spectabilis, a large-seeded tree species in a moist evergreen forest in Thailand." Journal of Tropical Ecology 20, no. 4 (July 2004): 421–27. http://dx.doi.org/10.1017/s0266467404001555.
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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.
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Sato, Hiroki. "Seasonal fruiting and seed dispersal by the brown lemur in a tropical dry forest, north-western Madagascar." Journal of Tropical Ecology 29, no. 1 (January 2013): 61–69. http://dx.doi.org/10.1017/s0266467413000011.
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Abstract:Community-wide seasonal fruiting and seed dispersal by the common brown lemur (Eulemur fulvus fulvus) was investigated in a tropical dry forest, north-western Madagascar. The brown lemur is the sole disperser of large seeds > 10 mm in diameter. Considering the limited assemblage of dispersers, large-seeded plants should display distinctive fruiting patterns to acquire dispersers. To compare fruiting patterns and seed dispersal by the brown lemur between small-seeded and large-seeded plants, fruiting conditions for 432 trees on a transect, feeding activity over 1212 h of observation, and the composition of 1126 dung samples were recorded for 1 y. Seeds of a total of 52 species were identified through both observations and faecal analysis. As rainfall increased, larger numbers of species and individuals of small-seeded plants fruited. Among the 52 species, the brown lemur dispersed 29 and 13 species with small and large seeds, respectively, during the rainy season. High moisture levels probably favoured seed germination and seedling establishment in various species. During the dry season, although small-seeded species rarely fruited, a few large-seeded species, particularly Vitex beraviensis, formed a long-term fruiting peak and provided essential food resources for the brown lemur. Because seeds of these large-seeded plants were frequently dispersed by the brown lemur, dry-season fruiting seemed to be favourable to avoid competition for dispersers with other plant species.
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Navarro, Teresa, Jalal El Oualidi, and Mohammed Sghir Taleb. "Relationship between seed size and related functional traits in North Saharan Acacia woodlands." Plant Ecology and Evolution 151, no. 1 (March 28, 2018): 87–95. http://dx.doi.org/10.5091/plecevo.2018.1368.
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Background and aims – North Saharan Acacia woodland is a fragile ecosystem altered by desertification and human activities. Little research has been conducted on the ecology of North Saharan Acacia woodland species. Seed size is a key trait to determine germination success, survival rate and establishment of Acacia woodland species under desert constraints.Methods – We analysed seed-size relationships in 42 selected woody plants in four different types of Acacia woodland vegetation which correspond to 26 plant species. We examined the correlation among seed size, fruit size, plant height, leaf size and flowering time and we tested seed size and fruit size variation among growth forms, dispersal modes and mechanisms to prevent dispersal. Key results – Close relationships were found between seed size and fruit size (r = 0. 77**), between fruit size and plant height (r = 0.51**) and between seed size and flowering duration (r = -0.46*) and a weak positive relationship was found between fruit and leaf size. Species with restricted spatial dispersal tended to have smaller seeds and fruits compared to those with well-developed spatial dispersal. Species which disperse and germinate throughout the year tended to have large diaspores, whereas species with seasonal germination tended to have small diaspores. The relationship between seed size and growth form/plant height was strong for gravity-dispersed (barochorous) species secondarily dispersed by vertebrates (Ziziphus lotus), seeds with secondary wind-assisted dispersal (Zilla spinosa subsp. macroptera) and for restricted-dispersal species (Tetraena gaetula). Precocious, short-flowering species that spread dispersal and germination over time (Acacia tortilis subsp. raddiana) tended to have large seeds. Early- and long-flowering herbaceous species tended to have small seeds (Brocchia cinerea).Conclusion – Close relationships are found between seed size and fruit size, between fruit size and plant height and between seed size and flowering duration in Moroccan Acacia woodland species.