نتایج جستجو برای: dispersal

تعداد نتایج: 19935  

Journal: :The American naturalist 2015
Carlos J Melián Vlastimil Křivan Florian Altermatt Petr Starý Loïc Pellissier Frederik De Laender

Studies of food webs suggest that limited nonrandom dispersal can play an important role in structuring food webs. It is not clear, however, whether density-dependent dispersal fits empirical patterns of food webs better than density-independent dispersal. Here, we study a spatially distributed food web, using a series of population-dispersal models that contrast density-independent and density...

Journal: :Journal of nematology 1995
D I Shapiro G L Tylka E C Berry L C Lewis

Previous studies indicated that dispersal of S. carpocapsae may be enhanced in soil with earthworms. The objective of this research was to determine and compare the effects of earthworms on dispersal of other Steinernema spp. Vertical dispersal of Steinernema carpocapsae, S. feltiae, and S. glaseri was tested in soil columns in the presence and absence of earthworms (Lumbricus terrestris). Disp...

Journal: :Molecular ecology 2010
Alisa P Ramakrishnan Trieste Musial Mitchell B Cruzan

While it is generally recognized that noncontiguous (long-distance) dispersal of small numbers of individuals is important for range expansion over large geographic areas, it is often assumed that colonization on more local scales proceeds by population expansion and diffusion dispersal (larger numbers of individuals colonizing adjacent sites). There are few empirical studies of dispersal modes...

Journal: :Proceedings. Biological sciences 2009
Calvin Dytham

Dispersal is a key component of a species's ecology and will be under different selection pressures in different parts of the range. For example, a long-distance dispersal strategy suitable for continuous habitat at the range core might not be favoured at the margin, where the habitat is sparse. Using a spatially explicit, individual-based, evolutionary simulation model, the dispersal strategie...

2018
David J Stasek James N Radl Thomas O Crist

Trophic interactions are often studied within habitat patches, but among-patch dispersal of individuals may influence local patch dynamics. Metacommunity concepts incorporate the effects of dispersal on local and community dynamics. There are few experimental tests of metacommunity theory using insects compared to those conducted in microbial microcosms. Using connected experimental mesocosms, ...

2012
Sarder Mohammed Asaduzzaman Geoff Wild

We consider a model for the evolution of dispersal of offspring. Dispersal is treated as a parental trait that is expressed conditional upon a parent's own "migration status," that is, whether a parent, itself, is native or nonnative to the area in which it breeds. We compare the evolution of this kind of conditional dispersal to the evolution of unconditional dispersal, in order to determine t...

2014
Juan J Robledo-Arnuncio Etienne K Klein Helene C Muller-Landau Luis Santamaría

Dispersal of pollen and seeds are essential functions of plant species, with far-reaching demographic, ecological and evolutionary consequences. Interest in plant dispersal has increased with concerns about the persistence of populations and species under global change. We argue here that advances in plant dispersal ecology research will be determined by our ability to surmount challenges of sp...

2003
Robin E. Snyder

Robin E. Snyder* and Peter Chesson Section of Evolution and Ecology, University of California, Davis, CA 95616, USA *Correspondence: E-mail: [email protected] Abstract In the presence of permanent spatial heterogeneity, local dispersal, especially short-range dispersal, can facilitate coexistence by concentrating low-density species in the areas where their rates of increase are higher. We p...

Journal: :Ecology 2006
Sabrina E Russo Stephen Portnoy Carol K Augspurger

Seed dispersal fundamentally influences plant population and community dynamics but is difficult to quantify directly. Consequently, models are frequently used to describe the seed shadow (the seed deposition pattern of a plant population). For vertebrate-dispersed plants, animal behavior is known to influence seed shadows but is poorly integrated in seed dispersal models. Here, we illustrate a...

2014
Jennifer A. Moore Hope M. Draheim Dwayne Etter Scott Winterstein Kim T. Scribner

Understanding the factors that affect dispersal is a fundamental question in ecology and conservation biology, particularly as populations are faced with increasing anthropogenic impacts. Here we collected georeferenced genetic samples (n = 2,540) from three generations of black bears (Ursus americanus) harvested in a large (47,739 km2), geographically isolated population and used parentage ana...

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