The Role Of Predator Overlap In The Robustness And Extinction Of A Four Species Predatorprey Network

Predators and preys often form species networks with asymmetric patterns of interaction. We study the dynamics of a four species network consisting of two weakly connected predatorprey pairs. We focus our analysis on the effects of the cross interaction between the predator of the first pair and the prey of the second pair. This is an example where the predator overlap, which is the proportion of predators that a given prey shares with other preys, is not uniform across the network due to asymmetries in patterns of interaction. We explore the behavior of the system under different interaction strengths and study the dynamics of survival and extinction. In particular, we consider situations in which the four species have initial populations lower than their long-term equilibrium, simulating catastrophic situations in which their abundances are reduced due to human action or environmental change. We show that, under these reduced initial conditions, and depending on the strength of the cross interaction, the populations tend to oscillate before re-equilibrating, disturbing the community equilibrium and sometimes reaching values that are only a small fraction of the equilibrium population, potentially leading to their extinction. We predict that, contrary to one's intuition, the most likely scenario is the extinction of the less predated preys. © 2010 Elsevier B.V. All rights reserved.3892147254733(1975) Ecology and Evolution of Communities, , M. Cody, J. Diamond, Belknap Press New YorkPimm, S.L., (2002) Food Webs, , 2nd ed. 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Similarities And Differences In E±-molecule Scattering: Applications Of The Schwinger Multichannel Method

In this paper, we present a comparative study of low energy electron and positron scattering by H2 and N2 molecules, using the Schwinger multichannel (SMC) method. We briefly discuss the elastic collision of electrons and positrons by H2 below positronium formation threshold. The electronic excitation of N2 by electron impact is then compared with available data in the literature and with previously published results by positron impact. Strategies to treat the nuclear dynamics in the collision process, specifically adiabatic approximation for direct scattering and boomerang model for resonant scattering, are introduced within the SMC context. Partial results for H2 are shown. © 2006 Elsevier B.V. All rights reserved.2471 SPEC. ISS.1319Baranoski, G.V.G., Rokne, J.G., Shirley, P., Trondsen, T.S., Bastos, R., (2003) J. Visual. Comput. Animat., 14, p. 43Grill, A., (1994) Cold Plasma Materials Fabrication: From Fundamentals to Applications, , Wiley-IEEE Press, New YorkBaragiola, R.A., (2005) Nucl. Instr. and Meth. B, 232, p. 98Boldyrev, S., Gwinn, C.R., (2005) Astroph. J. (Part 1), 624, p. 213Karwasz, G.P., Zecca, A., Brusa, R.S., Pliszka, D., (2004) J. Alloys Compd., 382, p. 244Doghmi, K., (2005) Presse Med., 34, p. 227Johnson, W.N., Haymes, R.C., Harnden, F.R., Shore, S.N., (1972) Astroph. J., 172, pp. L1Guessoum, N., Jean, P., Gillard, W., (2005) Astr. Astroph., 436, p. 171Chase, D.M., (1956) Phys. Rev., 104, p. 838Takatsuka, K., McKoy, V., (1984) Phys. Rev. A, 30, p. 1734Germano, J.S.E., Lima, M.A.P., (1993) Phys. Rev. A, 47, p. 3976Lino, J.L.S., Germano, J.S.E., da Silva, E.P., Lima, M.A.P., (1998) Phys. Rev. A, 58, p. 3502Gibson, T.L., Lima, M.A.P., Takatsuka, K., McKoy, V., (1984) Phys. Rev. A, 30, p. 3005Kauppila, W.E., Stein, T.S., (1989) Adv. At. Mol. Opt. Phys., 26, p. 1Kimura, M., Sueka, O., Hamada, A., Itikawa, Y., (2000) Adv. Chem. Phys., 111, p. 537Jones, R.K., (1985) Phys. Rev. A, 31, p. 2898Hoffman, K.R., Dababneh, M.S., Hsieh, Y.-F., Kauppila, W.E., Pol, V., Smart, J.H., Stein, T.S., (1982) Phys. Rev. A, 25, p. 1393de Carvalho, C.R.C., Varella, M.T.N., da Silva, E.P., Germano, J.S.E., Lima, M.A.P., (2000) Nucl. Instr. and Meth. B, 171, p. 33Chaudhuri, P., Varella, M.T.N., Carvalho, C.R.C., Lima, M.A.P., (2004) Phys. Rev. A, 69, p. 042703Goddard III, W.A., Hunt, W.J., (1974) Chem. Phys. Lett., 24, p. 464da Costa, R.F., da Paixão, F.J., Lima, M.A.P., (2004) J. Phys. B, 37, pp. L129Chaudhuri, P., Varella, M.T.N., Carvalho, C.R.C., Lima, M.A.P., (2004) Nucl. Instr. and Meth. B, 221, p. 69Khakoo, M.A., Johnson, P.V., Ozkay, I., Yan, P., Trajmar, S., Kanik, I., (2005) Phys. Rev. A, 71, p. 062703Brunger, M.J., Teubner, P.J.O., (1990) Phys. Rev. A, 41, p. 1413Cartwright, D.C., Trajmar, S., Chutjian, A., Williams, W., (1977) Phys. Rev. A, 16, p. 1041Trajmar, S., Register, D.F., Chutjian, A., (1983) Phys. Rep., 97, p. 221Sullivan, J.P., Marler, J.P., Gilbert, S.J., Buckman, S.J., Surko, C.M., (2001) Phys. Rev. Lett., 87, p. 073201Ajello, J.M., Shemansky, D.E., (1985) J. Geophys. Res. Space Phys., 90, p. 9845Mason, N.J., Newell, W.R., (1987) J. Phys. B, 20, p. 3913Campbell, L., Brunger, M.J., Nolan, A.M., Kelly, L.J., Wedding, A.B., Harrison, J., Teubner, P.J.O., McLaughlin, B., (2001) J. Phys. B, 34, p. 1185Ehrhardt, H., Langhans, L., Linder, F., Taylor, H.S., (1968) Phys. Rev., 173, p. 222Sullivan, J.P., Gilbert, S.J., Surko, C.M., (2001) Phys. Rev. Lett., 86, p. 1494da Silva, A.J.R., Lima, M.A.P., Brescansin, L.M., McKoy, V., (1990) Phys. Rev. A, 41, pp. R2903Stibbe, D.T., Tennyson, J., (1997) Phys. Rev. Lett., 79, p. 4116Stibbe, D.T., Tennyson, J., (1998) J. Phys. B, 31, p. 815Comer, J., Read, F.H., (1971) J. Phys. B, 4, p. 368Weingartshofer, A., Clarke, E.M., Holmes, J.K., McGowan, J.W., (1975) J. Phys. B, 8, p. 1552Sullivan, J.P., Gilbert, S.J., Buckman, S.J., Surko, C.M., (2001) J. Phys. B, 34, pp. L467Varella, M.T.d.N., de Carvalho, C.R.C., Lima, M.A.P., (2001) New Directions in Antimatter Chemistry and Physics, p. 493. , Kluwer Academic Publisher, DordrechtDubé, L., Herzenberg, A., (1979) Phys. Rev. A, 20, p. 194Hazi, A.U., Rescigno, T.N., Kurilla, M., (1981) Phys. Rev. A, 23, p. 108