11 research outputs found
Bushmeat hunting changes regeneration of African rainforests.
To assess ecological consequences of bushmeat hunting in African lowland rainforests, we compared paired sites, with high and low hunting pressure, in three areas of southeastern Nigeria. In hunted sites, populations of important seed dispersers-both small and large primates (including the Cross River gorilla, Gorilla gorilla diehli)-were drastically reduced. Large rodents were more abundant in hunted sites, even though they are hunted. Hunted and protected sites had similar mature tree communities dominated by primate-dispersed species. In protected sites, seedling communities were similar in composition to the mature trees, but in hunted sites species with other dispersal modes dominated among seedlings. Seedlings emerging 1 year after clearing of all vegetation in experimental plots showed a similar pattern to the standing seedlings. This study thus verifies the transforming effects of bushmeat hunting on plant communities of tropical forests and is one of the first studies to do so for the African continent
MammalData
Data on number of groups of mammals observed per transect. Numbers are given for each of four guilds (Large primates, Medium primates, Rodents, and Browsers). Six study sites are included: Forests A, B, and C are each divided into one hunted and one protected site. In each site four transects were surveyed
Survival data
Data for survival analysis in the paper. The response is obs, indicating if an individual seedling was observed on the second visit
Data from: Competition, seed dispersal, and hunting: what drives germination and seedling survival in an Afrotropical forest?
Disentangling the contributions of different processes that influence plant recruitment, such as competition and seed dispersal, is important given the increased human-mediated changes in tropical forest ecosystems. Previous studies have shown that seedling communities in an Afro-tropical rainforest in Southeastern Nigeria are strongly affected by the loss of important seed dispersing primates, including Cross River gorillas (Gorilla gorilla diehli), chimpanzee (Pan troglodytes elioti), and drill (Mandrillus leucophaeus). Here we study how germination and survival of tree seedlings are affected by competition and reduced seed-dispersal in three contiguous forest reserves, in Southeastern Nigeria, with similar mature tree species composition and structure. We use an experimental design aimed at manipulating the effect of competition among seedlings in three protected and three hunted sites within the reserves. We use a total of sixty 5Ă—5 m plots of three types: plots cleared of all seedlings, plots selectively cleared of all primate-dispersed seedlings and control plots. All seedlings were identified, measured, assigned to dispersal mode, and tagged, and after one year we evaluated survival, mortality and new recruits. We found that in hunted sites germination of abiotically dispersed species was over four times higher in cleared plots compared to control plots, whereas germination of primate dispersed species was the same, which indicated that dispersal limitation was the dominant force in seedling recruitment in hunted sites. This was supported by the fact that the germination of all dispersal modes in the selectively cleared plots in protected sites was similar to the control plots in the same sites, but germination of abiotically dispersed species was significantly lower than in cleared plots in hunted sites. Competition among seedlings was mostly evident from the fact that 75% more seedlings of primate dispersed species germinated in cleared compared to control plots in protected sites. We conclude that inter-seedling competition may be irrelevant to seedling recruitment in hunted sites, where dispersal limitation appears to be a much stronger force shaping the seedling plant community, and thus hunting indirectly reverses the importance of competition and dispersal limitation in structuring seedling communities
Data for analyses of number of seedlings
The response is No, the number of seedlings in each plot, as described in the paper
Data from: Competition, seed dispersal, and hunting: what drives germination and seedling survival in an Afrotropical forest?
Disentangling the contributions of different processes that influence plant recruitment, such as competition and seed dispersal, is important given the increased human-mediated changes in tropical forest ecosystems. Previous studies have shown that seedling communities in an Afro-tropical rainforest in Southeastern Nigeria are strongly affected by the loss of important seed dispersing primates, including Cross River gorillas (Gorilla gorilla diehli), chimpanzee (Pan troglodytes elioti), and drill (Mandrillus leucophaeus). Here we study how germination and survival of tree seedlings are affected by competition and reduced seed-dispersal in three contiguous forest reserves, in Southeastern Nigeria, with similar mature tree species composition and structure. We use an experimental design aimed at manipulating the effect of competition among seedlings in three protected and three hunted sites within the reserves. We use a total of sixty 5Ă—5 m plots of three types: plots cleared of all seedlings, plots selectively cleared of all primate-dispersed seedlings and control plots. All seedlings were identified, measured, assigned to dispersal mode, and tagged, and after one year we evaluated survival, mortality and new recruits. We found that in hunted sites germination of abiotically dispersed species was over four times higher in cleared plots compared to control plots, whereas germination of primate dispersed species was the same, which indicated that dispersal limitation was the dominant force in seedling recruitment in hunted sites. This was supported by the fact that the germination of all dispersal modes in the selectively cleared plots in protected sites was similar to the control plots in the same sites, but germination of abiotically dispersed species was significantly lower than in cleared plots in hunted sites. Competition among seedlings was mostly evident from the fact that 75% more seedlings of primate dispersed species germinated in cleared compared to control plots in protected sites. We conclude that inter-seedling competition may be irrelevant to seedling recruitment in hunted sites, where dispersal limitation appears to be a much stronger force shaping the seedling plant community, and thus hunting indirectly reverses the importance of competition and dispersal limitation in structuring seedling communities
Data from: Bushmeat hunting changes regeneration of African rainforests
To assess ecological consequences of bushmeat hunting in African lowland rainforests, we compared paired sites, with high and low hunting pressure, in three areas of southeastern Nigeria. In hunted sites, populations of important seed dispersers—both small and large primates (including the Cross River gorilla, Gorilla gorilla diehli)—were drastically reduced. Large rodents were more abundant in hunted sites, even though they are hunted. Hunted and protected sites had similar mature tree communities dominated by primate-dispersed species. In protected sites, seedling communities were similar in composition to the mature trees, but in hunted sites species with other dispersal modes dominated among seedlings. Seedlings emerging 1 year after clearing of all vegetation in experimental plots showed a similar pattern to the standing seedlings. This study thus verifies the transforming effects of bushmeat hunting on plant communities of tropical forests and is one of the first studies to do so for the African continent
TreeData
Data on numbers of mature trees per transect section. Trees are divied into three dispersal modes (dispersed by primates, other animals, or by abiotic means). Each forest (A,B,C) has two study sites (one hunted, one protected), and each site has four 1 km transects divided into 200 m sections
SeedlingsClearedData
Data on number of seedlings per 5x5 m plots, one year after the plot was cleared of all vegetation. Seedling species are divied into three dispersal modes (dispersed by primates, other animals, or by abiotic means). Each forest (A,B,C) has two study sites (one hunted, one protected), and each site has four 1 km transects along which one plot is randomly placed
SeedlingsIntactData
Data on numbers of seedlings per 5x5 m plot. These data are from intact plots, with unmanipulated densities. Seedling species are divied into three dispersal modes (dispersed by primates, other animals, or by abiotic means). Each forest (A,B,C) has two study sites (one hunted, one protected), and each site has four 1 km transects along which two plots (A and B) are randomly placed