Dispersal of semi-fleshy fruits to rock crevices by a rock-restricted rodent

Seed dispersal allows successive generations of plants to be mobile in space and time. Heeria argentea’s unusual fruit and its ubiquity in extremely rocky habitats, suggests that this tree requires a specialist disperser. We therefore investigated the dispersal ecology of H. argentea and Hartogiella schinoides. We found M. namaquensis rapidly removed H. argentea and H. schinoides fruits, moving them short distances within and between rock outcrops, and consumed only the pericarps. Birds were observed consuming H. schinoides, but not H. argentea fruits, suggesting M. namaquensis is its sole, specialist disperser. Most H. argentea seeds (65%) with removed pericarps germinated successfully, while intact fruits did not. We show rock outcrops represent fire refugia, allowing H. argentea trees to grow to large sizes, with small stems and a co-occurring, wind-dispersed tree, Widdringtonia nodiflora found away from these sites. This rodent–tree mutualism is perhaps the clearest global example of directed dispersal and shows that these endemic trees are highly adapted for survival in the southwestern Cape habitat and are not tropical relicts.

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Fruit aromas in mature fleshy fruits as signals of readiness for predation and seed dispersal

New Phytologist ◽

10.1111/j.1469-8137.2012.04382.x ◽

2012 ◽

Vol 197 (1) ◽

pp. 36-48 ◽

Cited By ~ 71

Author(s):

Ana Rodríguez ◽

Berta Alquézar ◽

Leandro Peña

Keyword(s):

Seed Dispersal ◽

Fleshy Fruits

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Life-forms, pollination and seed dispersal syndromes in plant communities on ironstone outcrops, SE Brazil

Acta Botanica Brasilica ◽

10.1590/s0102-33062011000200016 ◽

2011 ◽

Vol 25 (2) ◽

pp. 395-412 ◽

Cited By ~ 26

Author(s):

Claudia Maria Jacobi ◽

Flávio Fonseca do Carmo

Keyword(s):

Seed Dispersal ◽

Life Form ◽

Life Forms ◽

Climatic Conditions ◽

Pollination Syndrome ◽

Rock Outcrops ◽

Dispersal Syndromes ◽

Se Brazil ◽

Seed Dispersal Syndromes ◽

Forest Islands

Rock outcrops play an important role in enhancing plant diversity in montane ecosystems. Ironstone outcrops (cangas) are among the lithotypes less known and most threatened in SE Brazil, due to mining activities. Besides species composition, a key feature to promote their conservation and restoration is the knowledge of the community prevalent life-forms, pollination and seed dispersal syndromes. The analyses were done based on published floristic surveys of cangas in SE Brazil. A total of 353 species of angiosperms (70 families) were assigned to one of the two predominant physiognomies (open areas and forest islands) on ironstone outcrops. Sixteen families responded for 70% of all species. Compared to Raunkiaer's spectrum, phanerophytes were over- and therophytes were under-represented. Phanerophytes were the predominant life-form in forest islands, while hemicryptophytes were outstanding in open areas. Entomophily was the dominant pollination syndrome in both habitats. Zoochory was dominant in forest islands and ranked last in open areas, where anemochory and autochory prevailed. Considering that both forest islands and open areas are subjected to the same climatic conditions, the results corroborate the influence of geoedaphic components in the three traits analysed.

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The role of the brown bear Ursus arctos as a legitimate megafaunal seed disperser

Scientific Reports ◽

10.1038/s41598-020-80440-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alberto García-Rodríguez ◽

Jörg Albrecht ◽

Sylwia Szczutkowska ◽

Alfredo Valido ◽

Nina Farwig ◽

...

Keyword(s):

Plant Regeneration ◽

Seed Dispersal ◽

Plant Species ◽

Ursus Arctos ◽

Mediterranean Forests ◽

Brown Bears ◽

Fleshy Fruits ◽

Seed Dispersers ◽

Regeneration Processes

AbstractMegafaunal frugivores can consume large amounts of fruits whose seeds may be dispersed over long distances, thus, affecting plant regeneration processes and ecosystem functioning. We investigated the role of brown bears (Ursus arctos) as legitimate megafaunal seed dispersers. We assessed the quantity component of seed dispersal by brown bears across its entire distribution based on information about both the relative frequency of occurrence and species composition of fleshy fruits in the diet of brown bears extracted from the literature. We assessed the quality component of seed dispersal based on germination experiments for 11 fleshy-fruited plant species common in temperate and boreal regions and frequently eaten by brown bears. Across its distribution, fleshy fruits, on average, represented 24% of the bear food items and 26% of the total volume consumed. Brown bears consumed seeds from at least 101 fleshy-fruited plant species belonging to 24 families and 42 genera, of which Rubus (Rosaceae) and Vaccinium (Ericaceae) were most commonly eaten. Brown bears inhabiting Mediterranean forests relied the most on fleshy fruits and consumed the largest number of species per study area. Seeds ingested by bears germinated at higher percentages than those from whole fruits, and at similar percentages than manually depulped seeds. We conclude that brown bears are legitimate seed dispersers as they consume large quantities of seeds that remain viable after gut passage. The decline of these megafaunal frugivores may compromise seed dispersal services and plant regeneration processes.

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Secondary seed dispersal of Ricinus communis Linnaeus (Euphorbiaceae) by ants in secondary growth vegetation in Minas Gerais

Revista Árvore ◽

10.1590/s0100-67622007000600005 ◽

2007 ◽

Vol 31 (6) ◽

pp. 1013-1018 ◽

Cited By ~ 4

Author(s):

Mário Marcos do Espírito Santo

Keyword(s):

Seed Dispersal ◽

Natural Population ◽

Ricinus Communis ◽

Secondary Growth ◽

Dispersal Distance ◽

Southeastern Brazil ◽

Atta Sexdens ◽

Directed Dispersal ◽

Ballistic Dispersal ◽

Secondary Seed Dispersal

In this study, I tested the efficacy of ants as secondary seed dispersers of Ricinus communis in southeastern Brazil. In a natural population of 143 individuals, I determined the ballistic dispersal distance for 62 seeds and 100 additional seeds were experimentally offered to ants in groups of ten seeds along a transect of 50 m. Fifty-three seeds were removed by ants, mainly by the leafcutter Atta sexdens (90.4%). The dispersal distance by ants was high, compared to the global average (4.38 m ± 0.74 m vs. 0.96 m), but was lower than the ballistic distance (7.27 m ± 0.13 m). Ants increased the total dispersal distance (8.66 m ± 0.60 m), but the main benefit for the plant was the directed dispersal, with seed deposition on the enriched soil of ant nests.

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Seed Dispersal by Brown Bears, Ursus arctos, in Southeastern Alaska

The Canadian Field-Naturalist ◽

10.22621/cfn.v118i4.53 ◽

2004 ◽

Vol 118 (4) ◽

pp. 499 ◽

Cited By ~ 13

Author(s):

Mary F. Willson ◽

Scott M. Gende

Keyword(s):

Seed Dispersal ◽

Plant Species ◽

Ursus Arctos ◽

Forest Understory ◽

Habitat Distribution ◽

Brown Bears ◽

Fleshy Fruits ◽

Scat Analyses

Mammals often consume fleshy fruits and disperse significant quantities of the enclosed seeds. In southeastern Alaska, Brown Bears (Ursus arctos) are among the most important dispersers of seeds for the numerous plant species producing fleshy fruits, because these bears are abundant, often eat large quantities of fruit, and commonly excrete seeds in germinable condition. Scat analyses showed that Brown Bears on Chichagof Island ate increasing quantities of fruit through summer and fall. Scats commonly contained several thousand seeds, often of two or more species. Four kinds of seeds of fleshyfruited plants that normally grow in forest understory germinated at similar levels when experimentally deposited (in bear scats) in the two most common habitats (forest and muskeg), suggesting that habitat distribution of these plants is not determined simply by germination patterns. Although seed passage through bear digestive tracts and the composition of scats are known to affect germination rates to some degree, the most important role of bears in seed dispersal is probably transport.

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Odor of achlorophyllous plants' seeds drives seed-dispersing ants

10.22541/au.160994842.26346825/v1 ◽

2021 ◽

Author(s):

Mikihisa Yamada ◽

Masaru Hojo ◽

Akio Imamura

Keyword(s):

Seed Dispersal ◽

Fleshy Fruit ◽

Herbaceous Plant ◽

Evolutionary Pathway ◽

Fungal Host ◽

Directed Dispersal ◽

Important Means ◽

Moisture Conditions ◽

Achlorophyllous Plants

Seed dispersal by ants is an important means of migration for plants. Although many 34 myrmecochorous plants have seeds containing elaiosome, a nutritional reward for ants, some 35 non-myrmecochorous seeds without elaiosomes are also dispersed by ant species. However, the 36 mechanism by which seeds without elaiosomes enable efficient dispersal by ants is scarcely 37 investigated. The seeds of the achlorophyllous and myco-heterotrophic herbaceous plant 38 Monotropastrum humile are very small without elaiosomes and require a fungal host for 39 germination and survival. We performed a bioassay using seeds of M. humile and the ant 40 Nylanderia flavipes to demonstrate ant-mediated seed dispersal. We also analyzed the volatile 41 odors emitted from M. humile seeds and conducted bioassays using dummy seeds coated with 42 seed volatiles. Although elaiosomes were absent from the M. humile seeds, the ants carried the 43 seeds to their nests. They also carried the dummy seeds coated with the seed volatile mixture to 44 the nest, and left some dummy seeds inside the nest and discarded the rest of the dummy seeds 45 outside the nest with a bias toward locations with moisture conditions, which might be 46 conducive to germination. We concluded that seeds of M. humile were dispersed by the ants, 47 and that seed odors were sufficient to induce directed dispersal even without elaiosomes. It is 48 probable that the fleshy fruit producing genus Monotropastrum evolved from the related 49 anemochorous genus Monotropa, which produces capsule fruit. This transformation from 50 anemochory to myrmecochory presents a novel evolutionary pathway toward ant-mediated seed 51 dispersal in an achlorophyllous plant.

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