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Libro de Resúmenes / Book of Abstracts (Español/English)

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Resumenes 24<br />

X<br />

µ<br />

⎧<br />

⎪<br />

⎪ dX<br />

⎪<br />

⎪<br />

dt<br />

⎪<br />

: ⎨<br />

⎪<br />

⎪<br />

⎪ dY<br />

⎪<br />

⎪ dt<br />

⎪<br />

⎩<br />

⎛<br />

= r⎜1<br />

−<br />

⎝<br />

X<br />

K<br />

⎛ αX<br />

⎞<br />

q ⎜ X − ⎟<br />

⎞ ⎝ X + β<br />

−<br />

⎠<br />

⎟ X<br />

Y<br />

⎠ αX<br />

X − + a<br />

X + β<br />

⎛ ⎛ αX<br />

⎞ ⎞<br />

⎜ p⎜<br />

X − ⎟ ⎟<br />

⎜ ⎝ X + β ⎠ ⎟<br />

= ⎜<br />

− c ⎟ Y<br />

αX<br />

⎜ X − + a ⎟<br />

⎜<br />

⎟<br />

⎝<br />

X + β<br />

⎠<br />

8<br />

con µ = ( r , K,<br />

q,<br />

a,<br />

p,<br />

c,<br />

α,<br />

β ) ∈ ℜ+<br />

, don<strong>de</strong> Y = Y() t representa el tamaño<br />

poblacional <strong>de</strong> los <strong>de</strong>predadores para t ≥ 0 y los parámetros, todos<br />

positivos, tienen diferentes significados biológicos.<br />

El sistema obtenido es <strong>de</strong>l tipo Kolmogorov [Freedman 1980], y se<br />

<strong>de</strong>termina una región <strong>de</strong> invarianza, los puntos <strong>de</strong> equilibrios, estableciendo<br />

la naturaleza <strong>de</strong> cada uno <strong>de</strong> ellos y se obtienen condiciones en los<br />

parámetros para la existencia o no <strong>de</strong> ciclos límites.<br />

La importancia <strong>de</strong>l estudio <strong>de</strong>l uso <strong>de</strong> refugio por parte <strong>de</strong> las presas<br />

es relevante en los proceso <strong>de</strong> conservación <strong>de</strong> especies en peligro <strong>de</strong><br />

extinción con la creación <strong>de</strong> reservas (refugios) para preservarlas<br />

[Srinivasu and Gayitri 2005]<br />

Dinamics in the Rosenzweig-McArthur predation mo<strong>de</strong>l<br />

consi<strong>de</strong>ring saturated refuge for prey.<br />

Commonly in Population Dynamics it is affirmed that prey refuge use<br />

has a stabilizing effect in system when <strong>de</strong>terministic continuous-time<br />

mo<strong>de</strong>ls for predator-prey interactions are employed [Collings 1995,<br />

Maynard-Smith 1974, Ruxton 1995, Sih 1987].<br />

If X = X(t) represents the prey population size, this affirmation it is<br />

possible to verify, <strong>de</strong>scribing the interaction with the Lotka-Volterra mo<strong>de</strong>l,<br />

and assuming that the quantity <strong>of</strong> prey in cover Xr is proportional to<br />

population size , that is X r = α X , or else, the quantity <strong>of</strong> population at<br />

refugia is constant., i. e. X r = β [Harrison 1979, Taylor 1984].<br />

When the predator-prey interaction is <strong>de</strong>scribed with by the wellknown<br />

Rosenzweig-McArthur mo<strong>de</strong>l [Murdoch 2003, Turchin, 2003], in<br />

González-Olivares and Ramos-Jiliberto, (2003) was <strong>de</strong>monstrated that for<br />

certain parameter constraints, the effect <strong>of</strong> refuge by a fraction <strong>of</strong> prey<br />

population implies oscillatory behavior due the apparition <strong>of</strong> limit cycles on<br />

system.<br />

At once, Ruxton [1995] constructs a mo<strong>de</strong>l assuming that the rate in<br />

which prey move to refuge , is proportional to predator <strong>de</strong>nsity, that is,<br />

= λ y , and it is prove that the refuge has a stabilizing effect.<br />

X r

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