نتایج جستجو برای: limited seed dispersal and intra
تعداد نتایج: 16872138 فیلتر نتایج به سال:
The western Ordos Plateau is a key area of shrub diversity and a National Nature Reserve of endangered shrub species in north-west China. Desert expansion is becoming the most important threat to these endangered species. However, little is known about the effects of sand burial on the dynamics of the shrub community. This study aims to investigate how the shrubs as a community and as different...
one of the most visible aspects of a forest stand structure is the spatial patterns of trees. competition affects on forest structure and its understanding is important, when the purpose of forest management is to imitate the dynamic of natural ecosystems. for this purpose, an unmanaged intact forest was selected with 26 hectares area. all chestnut leaf oak (quercus castaneifolia) trees with a ...
abstract previous researches have shown success of growth hormones usage on flower production increase, pod and prevention of abscission of them in some of the pulses. two tests were done, in order to find out the effects of growth hormones to on flower production increase, pod and chick pea yield composites in farmer conditions (2010-11) and green house conditions as factorial on the proje...
We combined data on gut-passage times, feeding, and movement to explore the patterns of seed dispersal by Eulemur rubriventer, Eulemur rufrifrons, and Varecia variegata editorum lemurs in Ranomafana National Park, Madagascar. These lemur species deposited less than half of their consumed seeds >100 m away from conspecific trees (40-50%). Long-distance dispersal (>500 m) was rare and average dis...
We investigated secondary dispersal of propagules of Erodiophyllum elderi (Asteraceae), a short-lived perennial plant growing in small patches in the arid lands of southern Australia. In spite of its importance for population dynamics, secondary dispersal is a little understood process. We monitored the dispersal of 2280 large woody capitula (seed heads) released in six E. elderi patches for 9 ...
Dispersal is a major and critical process in population biology that has been particularly challenging to study. Animals can have major roles in seed dispersal even in species that do not appear specifically adapted to animal-aided dispersal. This can occur by two processes: direct movement of diaspores by animals and modification of landscape characteristics by animals in ways that greatly inf...
Seed limitation, defined as the failure of seeds to arrive at sites favorable for recruitment, may be a critical force structuring plant communities. When seed limitation is strong, interspecific competition is reduced, and competitive exclusion may be slowed to the extent that diversity can be maintained through speciation and migration. In mature tropical forests, seed limitation may be espec...
Microstegium vimineum is a shade tolerant annual C4 invasive grass in the Eastern US, which has been shown to negatively impact species diversity and succession in hardwood forests. To date, empirical studies have shown that population expansion is limited to <1 m yr(-1), which is largely driven by gravity dispersal. However, this likely does not fully account for all mechanisms of population-s...
The spatial placement of recruits around adult conspecifics represents the accumulated outcome of several pattern-forming processes and mechanisms such as primary and secondary seed dispersal, habitat associations or Janzen-Connell effects. Studying the adult-recruit relationship should therefore allow the derivation of specific hypotheses on the processes shaping population and community dynam...
BACKGROUND Nut-bearing trees, including oaks (Quercus spp.), are considered to be highly dispersal limited, leading to concerns about their ability to colonize new sites or migrate in response to climate change. However, estimating seed dispersal is challenging in species that are secondarily dispersed by animals, and differences in disperser abundance or behavior could lead to large spatio-tem...
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