نتایج جستجو برای: dispersal
تعداد نتایج: 19935 فیلتر نتایج به سال:
We study a model of seed dispersal that considers the inclusion of an animal disperser moving diffusively, feeding on fruits and transporting the seeds, which are later deposited and capable of germination. The dynamics depends on several population parameters of growth, decay, harvesting, transport, digestion and germination. In particular, the deposition of transported seeds at places away fr...
ABSTRACT. An important question in the study of the evolution of dispersal is what kind of dispersal strategies are evolutionary stable. This work is motivated by recent work of Cosner et al. [9], in which they introduced a class of ideal free dispersal kernels and found conditions suggesting that they determine evolutionarily stable dispersal strategies. The goals of this paper are to introduc...
a study was conducted to determine habitat suitability of goitred gazelle (gazella subgutturosa) in kalmand-bahadoran protected area during four seasons of year 2003-2004.the geographic position of dispersal points of gazelle herds was recorded with global position system. the data were transmitted into attributed tables in arc view software and their layers were created. the maps of slope, alt...
Dispersal is a complex phenomenon affected by multiple factors. Among the factors that influence dispersal in the common lizard (Lacerta vivipara), poor maternal body condition and stress are known to decrease dispersal propensity of juveniles. But the effect of individual factors on dispersal could change when several of them act concurrently or at different developmental stages. Prenatal fact...
In plants, genes may disperse through both pollen and seeds. Here we provide a first theoretical study of the mechanisms and consequences of the joint evolution of pollen and seed dispersal. We focus on hermaphroditic self-compatible species distributed in structured populations, assuming island dispersal of pollen and seeds among small patches of plants within large populations. Three traits a...
In a spatiotemporally variable environment, plants use seed dispersal and dormancy to reduce risk. Intuition suggests that dormancy should be able to substitute for dispersal, so that dormancy will reduce the optimal mean dispersal distance, and previous theoretical studies using temporally uncorrelated environments have found this to be true. I show that in the presence of positive temporal co...
Scatter-hoarding rodents are effective dispersal agents for many plant species. Several studies have shown that rodents repeatedly re-cache seeds. The re-caching process often has a significant impact on final seedling establishment, but the factors determining its occurrence are poorly understood. In this study, we followed the fate of 3564 artificial seeds that varied in size, nutrient conten...
Exotic plant invasions have triggered environmental and economic problems throughout the world. Our ability to manage these invasions is hindered by the difficulty of predicting spread in fragmented landscapes. Because the spatial pattern of invasions depends on the dispersal characteristics of the invasive species and the configuration of suitable habitat within the landscape, a universal mana...
Myrmecochory is the process of seed dispersal by ants; however, it is highly challenging to study, mainly because of the small size of both partners and the comparatively large range of dispersal. The mutualistic interaction between ants and seeds involves the former retrieving diaspores, consuming their elaiosome (a nutrient-rich appendage), and the rejection of seeds from the nest. Here, we i...
Dispersal is a key demographic process, ultimately responsible for genetic connectivity among populations. Despite its importance, quantifying dispersal within and between populations has proven difficult for many taxa. Even in passerines, which are among the most intensely studied, individual movement and its relation to gene flow remains poorly understood. In this study we used two parallel g...
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