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Gut Passage (gut + passage)
Selected AbstractsGut passage effect of the introduced red-whiskered bulbul (Pycnonotus jocosus) on germination of invasive plant species in MauritiusAUSTRAL ECOLOGY, Issue 3 2009JANNIE F. LINNEBJERG Abstract In Mauritius, many of the worst invasive plant species have fleshy fruits and rely on animals for dispersal. The introduced red-whiskered bulbul (Pycnonotus jocosus) feeds on many fleshy-fruited species, and often moves from invaded and degraded habitats into higher quality native forests, thus potentially acting as a mediator of continued plant invasion into these areas. Furthermore, gut passage may influence seed germination. To investigate this, we fed fleshy fruits of two invasive plant species, Ligustrum robustum and Clidemia hirta, to red-whiskered bulbuls. Gut passage times of seeds were recorded. Gut-passed seeds were sown and their germination rate and germination success compared with that of hand-cleaned seeds, as well as that of seeds in whole fruits. Gut passage and hand-cleaning had significant positive effects on germination of both species. Gut-passed seeds of both C. hirta and L. robustum germinated faster than hand-cleaned seeds. However, for L. robustum, this was only true when compared with hand-cleaned seeds with intact endocarp; when compared with hand-cleaned seeds without endocarp, there was no difference. For overall germination success, there was a positive effect of gut passage for C. hirta, but not for L. robustum. For both C. hirta and L. robustum, no seeds in intact fruits geminated, suggesting that removal of pulp is essential for germination. Our results suggest that, first, the initial invasion of native forests in Mauritius may not have happened so rapidly without efficient avian seed dispersers like the red-whiskered bulbul. Second, the bulbul is likely to be a major factor in the continued re-invasion of C. hirta and L. robustum into weeded and restored conservation management areas. [source] Differences in endozoochorous dispersal between aquatic plant species, with reference to plant population persistence in riversFRESHWATER BIOLOGY, Issue 2 2005B. J. A. POLLUX Summary 1. In river ecosystems, populations are continuously subjected to unidirectional downstream currents resulting in a downstream movement of populations. To ensure long-term population persistence in rivers, organisms must have a mechanism for upstream dispersal, which allows them to re-colonise upstream areas. 2. In this study we assessed differences in the potential for endozoochorous seed dispersal of Sparganium emersum and Sagittaria sagittifolia, two aquatic plant species with different seed morphologies, by mallard (Anas platyrhynchos) and teal (Anas crecca), two duck species with different body weights. 3. We found no significant differences in seed retrieval (the proportion of ingested seeds retrieved after gut passage) and seed retention time (time between seed ingestion and retrieval), between mallard and teal, despite the difference in body weights. We did find a significantly higher germination (%) over retention time of S. emersum seeds retrieved from teal compared with mallard, most likely related to a more efficient removal of the seed coat during passage through the gut of teal. 4. There were large differences between S. emersum versus S. sagittifolia in: (i) seed retrieval (22.65 ± 20.8% versus 1.60 ± 2.4%, respectively); (ii) seed retention time in duck gut, with a maximum of 60 h versus 12 h; (iii) the effect of gut passage on seed germination, with an increase of approximately 35% versus a decrease of 25%; and (iv) the effect of gut passage on seed germination rate, with an acceleration of 10 days versus a delay of 3 days on average. The results show that S. emersum has a higher potential for endozoochorous dispersal by ducks and postdispersal establishment than S. sagittifolia. 5. We propose that, in rivers, bird-mediated seed dispersal may promote re-colonisation of upstream areas, enabling long-term plant population persistence. [source] Effects of gut passage, feces, and seed handling on latency and rate of germination in seeds consumed by capuchins (Cebus capucinus)AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Kim Valenta Abstract One of the key measures of the effectiveness of primary seed dispersal by animals is the quality of seed dispersal (Schupp: Plant Ecol 107/108 [1993] 15,29). We present data on quality of seed dispersal by two groups of white-faced capuchins (Cebus capucinus) in Costa Rica to test the hypothesis that capuchin seed handling results in effective primary dispersal for some fruit species they consume. We examined seed handling for 27 plant species, and germination rates of 18 species consumed by capuchins. For five of the most commonly swallowed seed species, we determined germination rates and average time to germination (latency) for seeds ingested and defecated by capuchins and compared these to seeds removed directly from fruit and planted. For the same five species, we compared germination rates and latency for passed seeds planted in capuchin feces to those cleaned of feces and planted in soil. For three of five species, differences in proportion of germinated seeds were significantly higher for gut passed seeds than for controls. For four of five species, germination latency was significantly faster for gut passed seeds than for controls. Feces had either no effect on seed germination rate or precluded germination. Data presented here support the hypothesis that white-faced capuchins are effective primary dispersers. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc. [source] Consequences of southern cassowary (Casuarius casuarius, L.) gut passage and deposition pattern on the germination of rainforest seedsAUSTRAL ECOLOGY, Issue 3 2010MATT G. BRADFORD Abstract In Australia's tropical rainforests the endangered southern cassowary, Casuarius casuarius, L., is the largest native frugivore and many plant species, because of the size of their fruits or seeds, are thought to be largely dependent on cassowaries for their dispersal. In this study we asked whether the contribution of cassowaries to plant recruitment extends beyond removing seeds from the vicinity of the parent. To do this we conducted germination trials involving 17 rainforest plant species to test whether cassowary consumption and seed deposition pattern alter germination probability or time to germination. Twenty-four per cent of species showed changed germination probabilities, with one species showing no germination without cassowary consumption, and 35% showed changed time to germination. However these differences did not translate into any significant effects when considered across all species. We examined gut scarification, fruit pulp removal (de-inhibition) and deposition in faecal material as mechanisms for changing germination success; each contributed to the changed success of individual species. There was a negative effect of seed clumping on five species. We conclude that cassowary consumption can modify germination performance in a minority of rainforest plants and that the effect is generally positive. Although the effect on large seeded species was small it is most likely to be important as the cassowary is the only animal in Australia able to internally process large numbers of these seeds. [source] Gut passage effect of the introduced red-whiskered bulbul (Pycnonotus jocosus) on germination of invasive plant species in MauritiusAUSTRAL ECOLOGY, Issue 3 2009JANNIE F. LINNEBJERG Abstract In Mauritius, many of the worst invasive plant species have fleshy fruits and rely on animals for dispersal. The introduced red-whiskered bulbul (Pycnonotus jocosus) feeds on many fleshy-fruited species, and often moves from invaded and degraded habitats into higher quality native forests, thus potentially acting as a mediator of continued plant invasion into these areas. Furthermore, gut passage may influence seed germination. To investigate this, we fed fleshy fruits of two invasive plant species, Ligustrum robustum and Clidemia hirta, to red-whiskered bulbuls. Gut passage times of seeds were recorded. Gut-passed seeds were sown and their germination rate and germination success compared with that of hand-cleaned seeds, as well as that of seeds in whole fruits. Gut passage and hand-cleaning had significant positive effects on germination of both species. Gut-passed seeds of both C. hirta and L. robustum germinated faster than hand-cleaned seeds. However, for L. robustum, this was only true when compared with hand-cleaned seeds with intact endocarp; when compared with hand-cleaned seeds without endocarp, there was no difference. For overall germination success, there was a positive effect of gut passage for C. hirta, but not for L. robustum. For both C. hirta and L. robustum, no seeds in intact fruits geminated, suggesting that removal of pulp is essential for germination. Our results suggest that, first, the initial invasion of native forests in Mauritius may not have happened so rapidly without efficient avian seed dispersers like the red-whiskered bulbul. Second, the bulbul is likely to be a major factor in the continued re-invasion of C. hirta and L. robustum into weeded and restored conservation management areas. [source] | ||||||||||