scholarly journals Seed Shadows of Northern Pigtailed Macaques within a Degraded Forest Fragment, Thailand

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1184
Author(s):  
Eva Gazagne ◽  
Jean-Luc Pitance ◽  
Tommaso Savini ◽  
Marie-Claude Huynen ◽  
Pascal Poncin ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Seedling Recruitment ◽  
Mechanistic Model ◽  
Cheek Pouch ◽  
Degraded Forest ◽  
Forest Fragment ◽  
Plantation Forests ◽  
Maximum Range ◽  
Seed Deposition ◽  
Seed Shadows

Research Highlights: Frugivores able to disperse large seeds over large distances are indispensable for seedling recruitment, colonization and regeneration of tropical forests. Understanding their effectiveness as seed dispersal agents in degraded habitat is becoming a pressing issue because of escalating anthropogenic disturbance. Although of paramount importance in the matter, animal behaviour’s influence on seed shadows (i.e., seed deposition pattern of a plant population) is difficult to evaluate by direct observations. Background and Objectives: We illustrated a modeling approach of seed shadows incorporating field-collected data on a troop of northern pigtailed macaques (Macaca leonina) inhabiting a degraded forest fragment in Thailand, by implementing a mechanistic model of seed deposition with random components. Materials and Methods: We parameterized the mechanistic model of seed deposition with macaque feeding behavior (i.e., consumed fruit species, seed treatments), gut and cheek pouch retention time, location of feeding and sleeping sites, monthly photoperiod and movement patterns based on monthly native fruit availability using Hidden Markov models (HMM). Results: We found that northern pigtailed macaques dispersed at least 5.5% of the seeds into plantation forests, with a majority of medium- to large-seeded species across large distances (mean > 500 m, maximum range of 2300 m), promoting genetic mixing and colonization of plantation forests. Additionally, the macaques produced complementary seed shadows, with a sparse distribution of seeds spat out locally (mean >50 m, maximum range of 870 m) that probably ensures seedling recruitment of the immediate plant populations. Conclusions: Macaques’ large dispersal distance reliability is often underestimated and overlooked; however, their behavioral flexibility places them among the last remaining dispersers of large seeds in disturbed habitats. Our study shows that this taxon is likely to maintain significant seed dispersal services and promote forest regeneration in degraded forest fragments.

scholarly journals Effects of Bird Traits on Seed Dispersal of Endangered Taxus chinensis (Pilger) Rehd. with Ex-Situ and In-Situ Conservation

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 790
Author(s):  
Li ◽  
Wang ◽  
Li ◽  
Yi ◽  
Yan ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Ex Situ Conservation ◽  
Seedling Recruitment ◽  
Bird Species ◽  
Ex Situ ◽  
Taxus Chinensis ◽  
Seed Removal ◽  
Seed Deposition

Biodiversity is rapidly decreasing worldwide. Its great importance has been attached to conservation through in-situ and ex-situ management. Animal-mediated seed dispersal is an important ecological process, linking the threatened plants and animal partners in ex-situ habitats, and in turn affecting tree conservation. However, how bird traits affect seed dispersal within in-situ and ex-situ conservation still remains unclear. Here, we aim to answer this question. We tested whether bird traits affect seed deposition and seedling recruitment. Our results showed that 19 bird species foraged and removed Taxus chinensis (Pilger) Rehd. seeds across botanical gardens (ex-situ) and natural reserves (in-situ). The seed dispersal pattern of T. chinensis varied in the stages of seed removal and seed deposition, but showed no significant difference in the seedling recruitment stage. This showed that bird morphological and behavioral traits affected seed dispersal through the different contributions of varying bird species. Large birds and their high visitation frequency played a central role in seed removal patterns. The frequency of post-foraging habitat use was the most important factor determining the role of birds in seed deposition and the following seedling recruitment. Urocissa erythrorhyncha and Chloropsis hardwickii played the role of keystone species in seed deposition and seedling recruitment, respectively. Our results highlight the importance of bird traits in facilitating the seed dispersal of trees within in-situ and ex-situ conservation, which should be considered in future forest conservation and management.

Quantity and spatial distribution of seeds dispersed by a western lowland gorilla population in south-east Cameroon

2015 ◽  
Vol 31 (3) ◽  
pp. 201-212 ◽  
Author(s):  
Charles-Albert Petre ◽  
Nikki Tagg ◽  
Roseline Beudels-Jamar ◽  
Barbara Haurez ◽  
Marcel Salah ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Seedling Recruitment ◽  
Gorilla Gorilla ◽  
Ecological Function ◽  
Canopy Openness ◽  
Central Position ◽  
Western Lowland Gorilla ◽  
Phase Dynamics ◽  
Sleeping Sites ◽  
Seed Deposition

Abstract:Understanding the ecological function of large frugivores in tropical forests is important considering their central position in seed-dispersal networks. This study illustrates the seed-dispersal effectiveness of a western lowland gorilla (Gorilla gorilla gorilla) population in Cameroon by looking at the interaction of seed quantity, species regeneration traits and the environmental characteristics of the deposition sites (sleeping sites vs. feeding trails) in order to discuss the role of gorillas within the ecosystem. The analysis of 1030 faecal samples collected over a 3-y period (September 2009–August 2012) showed that gorillas dispersed a diverse array of species (58 spp. identified), with an average of 289 intact seeds (>5 mm) d−1 per individual. Seed damage during mouth and gut processing occurred for 12 spp., generally accounting for <5% of specific seed load. Germination trials suggested that germination success of passed seeds remained unchanged (N = 6 spp.) or improved (N = 5 spp.) after gut passage compared with hand-cleaned seeds, with one exception. Indicator species identification (IndVal method) and General Discriminant Analysis suggested that sleeping sites (N = 36), as a main type of seed deposition site, correspond to regenerating microhabitats and correspondingly degree of canopy openness is one variable discriminating significantly this type of deposition site with random locations in the forest (N = 36) used as a proxy for non-directed seed deposition on feeding trails. With a mean canopy openness of 19–27%, sleeping sites offer optimal light conditions for the seedling recruitment of non-pioneer light-demanding species, the seeds of which encompass 47.4% of the total seed load dispersed over the 3-y period. From this study, it is hypothesized that the gorilla performed directed-dispersal of some light-demanding plant species at sleeping sites, and hence, by being actively implicated in gap-phase dynamics, fulfils a valuable ecological function within its ecosystem.

scholarly journals Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Fujita
Keyword(s):  
Seed Dispersal ◽  
Tree Species ◽  
Seedling Survival ◽  
Fire Suppression ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Forest Tree Species ◽  
Seed Deposition ◽  
Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

scholarly journals A mechanistic model for secondary seed dispersal by wind and its experimental validation

2005 ◽  
Vol 93 (5) ◽  
pp. 1017-1028 ◽  
Author(s):  
FRANK M. SCHURR ◽  
WILLIAM J. BOND ◽  
GUY F. MIDGLEY ◽  
STEVEN I. HIGGINS
Keyword(s):  
Seed Dispersal ◽  
Experimental Validation ◽  
Mechanistic Model ◽  
Secondary Seed Dispersal

Dispersal ofAcaciaseeds by ungulates and ostriches in an African savanna

1996 ◽  
Vol 12 (3) ◽  
pp. 345-356 ◽  
Author(s):  
Maxine F. Miller
Keyword(s):  
South Africa ◽  
Seed Dispersal ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Tree Crown ◽  
African Savanna ◽  
Large Herbivores ◽  
Mammalian Herbivores ◽  
Open Environments ◽  
Presence And Absence

ABSTRACTThe dispersal of AfricanAcaciaseeds in the presence and absence of large mammalian herbivores and ostriches was assessed in a savanna ecosystem in South Africa. In the absence of large herbivores,A. tortilisandA. niloticapods were mainly dispersed in the shade, directly beneath the tree crown and seeds remained in pods for over 18 months. In the presence of large herbivores,A. tortilis, A. niloticaandA. karrooseeds were freed from pods and were dispersed into open, non-shaded habitats. Impala dispersed mostA. tortilisseeds (18,900 ha−1), giraffe mostA. niloticaseeds (1060 ha−1) and giraffe and kudu mostA. karrooseeds (452 and 448 ha−1, respectively). Seedling survival in dung in open environments may exceed that of seedlings in soil shaded beneath the tree crown. It appears that seed dispersal by large herbivores may be advantageous to future seedling recruitment.

scholarly journals Spatiotemporal Patterns and Mechanisms of Chinese Tallowtree (Triadica sebifera) Spread along Edge Habitat in a Coastal Landscape, Mississippi, USA

2018 ◽  
Vol 11 (3) ◽  
pp. 117-126 ◽  
Author(s):  
Zhaofei Fan ◽  
Shaoyang Yang ◽  
Xia Liu
Keyword(s):  
Seed Dispersal ◽  
Negative Binomial ◽  
Seedling Recruitment ◽  
Light Availability ◽  
Spatiotemporal Patterns ◽  
Tree Age ◽  
Triadica Sebifera ◽  
Factors Affecting ◽  
Edge Habitat ◽  
Dispersal Mechanism

AbstractChinese tallowtree [Triadica sebifera(L.) Small] has reached unprecedented prevalence in coastal landscapes in the Gulf of Mexico, especially along edge habitat with low competition and abundant resource (e.g., light) availability. This study investigated the spatiotemporal patterns and mechanisms ofT. sebiferaspread along roadways and fire lines.Triadica sebiferaindividuals and landscape and community features were surveyed in equally spaced, spatially mapped plots. AllT. sebiferaindividuals were felled to determine tree age and status (seed trees or non-seed bearing trees), andT. sebiferaseed and seedling (≤2 yr old) densities and community and landscape features (over- and understory conditions, distance to seed trees) were measured. A zero-inflated negative binomial model was used to evaluate factors affectingT. sebiferaseed dispersal and seedling recruitment contributing to the observed spatiotemporal patterns. Introduced into the Grand Bay National Wildlife Refuge around 30 yr ago,T. sebiferatrees distribute in clustered patterns along roadways and fire lines and exhibit an exponential growth in density. HighT. sebiferaseed and seedling densities mainly occurred in sites that are ≤250 m from seed trees or have sparse overstory and high understory grass/herb coverage. With respect to the avian seed dispersal mechanism, the spatiotemporal patterns ofT. sebiferaspread along roadways and fire lines could be simply characterized by using landscape and community features that influence avian behaviors, including distance to seed trees, overstory tree density, and ground grass/herb coverage.

Seed-dispersal and seedling recruitment patterns by the last Neotropical megafaunal element in Amazonia, the tapir

2000 ◽  
Vol 16 (3) ◽  
pp. 369-385 ◽  
Author(s):  
José M. V. Fragoso ◽  
Jean M. Huffman
Keyword(s):  
Seedling Recruitment ◽  
Germination Rate ◽  
Seed Viability ◽  
Seed Rain ◽  
Dry Land ◽  
Forest Sites ◽  
Seed Dispersion ◽  
Tapirus Terrestris ◽  
Spatio Temporal ◽  
Seed Shadows

Tapirs (Tapiridae) are the last representatives of the Pleistocene megafauna of South and Central America. How they affect the ecology of plants was examined by studying the diversity, abundance, and condition of seeds defecated by the lowland tapir (Tapirus terrestris) in Amazonian Brazil. Additionally, the spatio-temporal pattern of the seed-rain and seed-shadows generated by tapirs was recorded. Three hundred and fifty-six tapir faeces were examined. Eleven per cent were found in water (n = 41), while 88% were located on dry land (n = 315). Of those found on dry land, 84% were located at sites that flood seasonally, while 14% of the total were encountered at forest sites that do not flood. In 127 faeces checked in the laboratory over 12 906 seeds of at least 39 species were found. Seed viability ranged from 65% for Maximiliana maripa to 98% for Enterolobium schomburgkii. Of nine seed species planted in the laboratory, seven germinated within 4 wk, with one species achieving an 89% germination rate. For many species recruitment to the seedling stage was also high under natural conditions, with 13 plant species occurring as seedlings in older faeces. Tapir generated seed-rain occurred throughout the year, with seeds defecated in all months. Two temporal patterns in species seed rain occurred: (1) contiguous monthly occurrence with peaks in abundance, and (2) discontinuous occurrence (time clumped) with small (a few months) to large (many months to more than a year) temporal gaps. The highest diversity of seeds appeared in April, at the end of the dry season. As the last of the Pleistocene megafauna of the region, tapirs may have particular importance as dispersers of large seeds and generators of unique seed dispersion patterns.

Pattern and impact of hornbill seed dispersal at nest trees in a moist evergreen forest in Thailand

2004 ◽  
Vol 20 (5) ◽  
pp. 545-553 ◽  
Author(s):  
Shumpei Kitamura ◽  
Takakazu Yumoto ◽  
Pilai Poonswad ◽  
Naohiko Noma ◽  
Phitaya Chuailua ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Breeding Season ◽  
Seedling Survival ◽  
Evergreen Forest ◽  
Seedling Mortality ◽  
Entire Process ◽  
Nest Sites ◽  
Seed Deposition ◽  
Number Of Seeds

Following the entire process of frugivore seed dispersal, from intake of seeds to seed deposition, is a difficult task. One alternative is to monitor areas of heavy seed rain deposited by animals. We quantified the number of seeds deposited by hornbills and followed the fates of these seedlings for 3 y to evaluate the effectiveness of hornbill seed dispersal at nest trees, on the basis of seedling survival. For 14 mo, fallen fruits and seeds were collected in traps established around four nest trees of each of two hornbill species (Aceros undulatus and Anthracoceros albirostris) and the seedlings were monitored in adjacent quadrats. Seedfall and seedlings of species represented in hornbill diets occurred at significantly higher densities in the traps/quadrats in front of nest cavities than in other traps/quadrats. Fewer seedling species and individuals germinated under nest trees than expected from the composition of the seedfall. Our results suggest that the quality of hornbill seed dispersal might be poor at nest trees due to the highly concentrated seedfall, which results in high seed and seedling mortality. Although seed deposition at nest trees is a useful guide to hornbill diet during the breeding season, it is clearly not of benefit to the plants involved. However, the pattern and consequences of hornbill seed dispersal at nest sites is likely very different from that during the non-breeding season.

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