Mark A. Lewis

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Observations on Mount St Helens indicate that the spread of recolonizing lupin plants has been slowed due to the presence of insect herbivores and it is possible that the spread of lupins could be reversed in the future by intense insect herbivory [Fagan, W. F. and J. Bishop (2000). Trophic interactions during primary sucession: herbivores slow a plant(More)
A large number of empirical studies have attributed Lévy search patterns to the foraging movements of animals. Typically, this is done by fitting a power-law distribution with an exponent of 1 < mu < or = 3 to the observed step lengths. Most studies record the animal's location at equally spaced time intervals, which are sometimes significantly longer than(More)
Numbers of non-indigenous species--species introduced from elsewhere - are increasing rapidly worldwide, causing both environmental and economic damage. Rigorous quantitative risk-analysis frameworks, however, for invasive species are lacking. We need to evaluate the risks posed by invasive species and quantify the relative merits of different management(More)
William F. Fagan Mark A. Lewis Michael G. Neubert and P. van den Driessche Department of Biology, Arizona State University, Tempe, AZ 85287±1501, USA. Tel. 480-965-8263. Fax +480-965-2519. E-mail bfagan@asu.edu Department of Mathematics, University of Utah, Salt Lake City, UT 84112, USA. Current Address: Department Mathematical Sciences and Department(More)
The continuing decline of ocean fisheries and rise of global fish consumption has driven aquaculture growth by 10% annually over the last decade. The association of fish farms with disease emergence in sympatric wild fish stocks remains one of the most controversial and unresolved threats aquaculture poses to coastal ecosystems and fisheries. We report a(More)
Patterns of space-use by individuals are fundamental to the ecology of animal populations influencing their social organization, mating systems, demography and the spatial distribution of prey and competitors. To date, the principal method used to analyse the underlying determinants of animal home range patterns has been resource selection analysis (RSA), a(More)
Recent literature on plant population spread advocates quantification of longdistance dispersal (LDD). These estimates could provide insights into rates of migration in response to climate change and rates of alien invasions. LDD information is not available for parameterization of current models because it is hard to obtain. We combine a new stochastic(More)
Marine salmon farming has been correlated with parasitic sea lice infestations and concurrent declines of wild salmonids. Here, we report a quantitative analysis of how a single salmon farm altered the natural transmission dynamics of sea lice to juvenile Pacific salmon. We studied infections of sea lice (Lepeophtheirus salmonis and Caligus clemensi) on(More)
Infectious diseases present ecological and public health challenges that can be addressed with mathematical models. Certain pathogens, however, including the emerging West Nile virus (WN) in North America, exhibit a complex seasonal ecology that is not readily analysed with standard epidemiological methods. We develop a single-season(More)
The discrete-time recursion system u_[n+1]=Q[u_n] with u_n(x) a vector of population distributions of species and Q an operator which models the growth, interaction, and migration of the species is considered. Previously known results are extended so that one can treat the local invasion of an equilibrium of cooperating species by a new species or mutant.(More)