This result provides direct evidence of long-lasting impacts of deer populations on plant species distribution. germanicum in 2006 increased not only with light indicator values, in accordance with its ecological requirements, but also with past deer browsing pressure. Logistic regression models revealed that the probability of occurrence of C. germanicum occurred in 8% of the plots in 1981, then 46% in 2006. germanicum has displayed an unexpected fast colonization rate during the last few decades but only in the northern part of the forest, which previously had the highest animal populations. Although initially rare and protected locally, C. In this area, deer populations reached a peak in the 1970s, then were reduced in order to meet forest management requirements. Based on coupled floristic and browsing surveys, repeated in time, we analysed the causes of the spatio-temporal progression of the epizoochorous species Cynoglossum germanicum over 30 years in a network covering an 11000 ha forested area in north-eastern France. But, in woodlands, direct links between the expansion of zoochorous plant species and ungulate presence have seldom been reported. Numerous plant colonizations have been putatively attributed to deer, based on plant species traits, fur brushing or dung analyses. altissima may not disperse primarily through water environments, this study suggests that secondary dispersal by water is possible and may allow for long-distance dispersal more than two orders of magnitude farther than recorded primary dispersal. Seeds kept in aqueous environments retained high germination rates (94.4 +/- 1.1%) even after 5 months. Germination rates for seeds that were kept in aqueous environments (Cheat Lake and the Monongahela River, near Morgantown, WV) were found to be similar to or higher than those in nearby terrestrial controls (F = 10.94, P = 0.0057). We found that biologically significant numbers of seeds disperse directly into water, remain buoyant, and are transported long distances by water. Using the exotic species, tree-of-heaven (Ailanthus altissima Swingle), in this study we estimated seed dispersal into water as a function of distance and experimentally tested seed buoyancy, secondary dispersal, and germinability after dispersal in water and on land. If seeds survive there, secondary dispersal in water may transport seeds long distances to suitable habitats. ![]() The consequences of deposition in an aqueous medium depend on whether seed viability is maintained. ![]() Once the seeds have been catalogued, Link and colleagues replant them to create corridors between isolated patches of forest.Īn audio descriptive version of the film is available via our media player.In mesic forest environments, seeds of wind-dispersed plant species may frequently be deposited in aqueous environments (e.g., lakes and rivers). Brown spider monkeys are critical seed dispersers, and as their numbers decrease, the forest is less able to regenerate.Īndres Link and Carolina Urbina Malo, scientists from Los Andes University in Colombia, are identifying the seeds that spider monkeys disperse to better understand the monkeys’ role in the forest and to predict which plants will be most affected by fragmentation. As the tropical forests of Colombia are cleared for farmland and cattle ranches, the remaining patches of forest become fewer, smaller, and farther apart from each other, threatening the survival of the animals that live there, including brown spider monkeys. Seed dispersers are critical to the forest’s ability to grow and regenerate. This video follows scientists studying the seeds that brown spider monkeys disperse in a tropical forest of Colombia in order to inform and improve reforestation efforts.
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