Abstract
Invasion, the growth in numbers and spatial spread of a population over time, is a fundamental process in ecology. Governments and businesses expend vast sums to prevent and control invasions of pests and pestilences and to promote invasions of endangered species and biological control agents. Many mathematical models of biological invasions use nonlinear integrodifference equations to describe the growth and dispersal processes and to predict the speed of invasion fronts. Linear models have received less attention, perhaps because they are difficult to simulate for large times.
In this paper, we use the saddle-point method, alias the method of steepest descent, to derive asymptotic approximations for the solutions of linear integrodifference equations. We work through five examples, for Gaussian, Laplace, and uniform dispersal kernels in one dimension and for asymmetric Gaussian and radially symmetric Laplace kernels in two dimensions. Our approximations are extremely close to the exact solutions, even for intermediate times. We also employ an empirical saddle-point approximation to predict densities using dispersal data. We use our approximations to examine the effects of censored dispersal data on estimates of invasion speed and population density.
Similar content being viewed by others
References
Andersen, M., 1991. Properties of some density-dependent integrodifference equation population models. Math. Biosci. 104, 135–157.
Britton, N.F., 1986. Reaction-Diffusion Equations and Their Applications to Biology. Academic, London.
Brown, J.K.M., Hovmoller, M.S., 2002. Aerial dispersal of pathogens on the global and continental scales and its impact on plant disease. Science 297, 537–541.
Bullock, J.M., Clarke, R.T., 2000. Long distance seed dispersal by wind: measuring and modelling the tail of the curve. Oecologia 124, 506–521.
Butler, R.W., 2007. Saddlepoint Approximations with Applications. Cambridge University Press, Cambridge.
Cain, M.L., Milligan, B.G., Strand, A.E., 2000. Long-distance seed dispersal in plant populations. Am. J. Bot. 87, 1217–1227.
Caswell, H., Lensink, R., Neubert, M.G., 2003. Demography and dispersal: life table response experiments for invasion speed. Ecology 84, 1968–1978.
Clark, J.S., 1998. Why trees migrate so fast: Confronting theory with dispersal biology and the paleorecord. Am. Nat. 152, 204–224.
Clark, J.S., Horvath, L., Lewis, M., 2001. On the estimation of spread rate for a biological population. Stat. Probab. Lett. 51, 225–234.
Cobbold, C.A., Lewis, M.A., Lutscher, F., Roland, J., 2005. How parasitism affects critical patch-size in a host–parasitoid model: application to the forest tent caterpillar. Theor. Popul. Biol. 67, 109–125.
Cohen, A., 1991. A Padé approximant to the inverse Langevin function. Rheol. Acta 30, 270–273.
Daniels, H.E., 1954. Saddlepoint approximations in statistics. Ann. Math. Stat. 25, 631–650.
Domb, C., Offenbacher, E.L., 1978. Random walks and diffusion. Am. J. Phys. 46, 49–56.
Fagan, W.F., Lewis, M., Neubert, M.G., Aumann, C., Apple, J.L., Bishop, J.G., 2005. When can herbivores slow or reverse the spread of an invading plant? A test case from Mount St. Helens. Am. Nat. 166, 669–685.
Feller, W., 1971. An Introduction to Probability Theory and its Applications, vol. II. Wiley, New York.
Feuerverger, A., 1989. On the empirical saddlepoint approximation. Biometrika 76, 457–464.
Fisher, R.A., 1937. The wave of advance of advantageous genes. Ann. Eugen. 7, 355–369.
Fort, J., 2007. Fronts from complex two-dimensional dispersal kernels: Theory and application to Reid’s paradox. J. Appl. Phys. 101, 094701.
Giffin, W.C., 1975. Transform Techniques for Probability Modeling. Academic, New York.
Good, I.J., 1957. Saddle-point methods for the multinomial distribution. Ann. Math. Stat. 28, 861–881.
Goutis, C., Casella, G., 1999. Explaining the saddlepoint approximation. Am. Stat. 53, 216–224.
Hart, D.R., Gardner, R.H., 1997. A spatial model for the spread of invading organisms subject to competition. J. Math. Biol. 35, 935–948.
Higgins, S.I., Richardson, D.M., 1999. Predicting plant migration rates in a changing world: the role of long-distance dispersal. Am. Nat. 153, 464–475.
Hughes, B.D., 1995. Random Walks and Random Environments. Volume 1: Random Walks. Oxford University Press, Oxford.
Jacquemyn, H., Brys, R., Neubert, M.G., 2005. Fire increases invasive spread of Molinia caerulea mainly through changes in demographic parameters. Ecol. Appl. 15, 2097–2108.
Jakeman, E., Pusey, P.N., 1976. A model for non-Rayleigh sea echo. IEEE Trans. Antennas Propag. 24, 806–814.
Kot, M., 1992. Discrete-time travelling waves: ecological examples. J. Math. Biol. 30, 413–436.
Kot, M., Schaffer, W.M., 1986. Discrete-time growth–dispersal models. Math. Biosci. 80, 109–136.
Kot, M., Lewis, M.A., van den Driessche, P., 1996. Dispersal data and the spread of invading organisms. Ecology 77, 2027–2042.
Kotz, S., Kozubowski, T.J., Podgorski, K., 2001. The Laplace Distribution and Generalizations: A Revisit with Applications to Communications, Economics, Engineering, and Finance. Birkhäuser, Boston.
Krkosek, M., Lauzon-Guay, J.S., Lewis, M.A., 2007. Relating dispersal and range expansion of California sea otters. Theor. Popul. Biol. 71, 401–407.
Lewis, M.A., 1997. Variability, patchiness, and jump dispersal in the spread of an invading population. In D. Tilman, P. Kareiva (Eds.) Spatial Ecology: The Role of Space in Population Dynamics and Interspecific Interactions, pp. 46–69. Princeton University Press, Princeton.
Lewis, M.A., Neubert, M.G., Caswell, H., Clark, J., Shea, K., 2006. A guide to calculating discrete-time invasion rates from data. In M.W. Cadotte, S.M. McMahon, T. Fukami (Eds.) Conceptual Ecology and Invasions Biology: Reciprocal Approaches to Nature, pp. 169–192. Springer, Dordrecht.
Lobatschewsky, N., 1842. Probabilité des résultats moyens tirés d’observations répetées. J. Reine Angew. Math. 24, 164–170.
Lui, R., 1983. Existence and stability of travelling wave solutions of a nonlinear integral operator. J. Math. Biol. 16, 199–220.
Lusk, E.J., Wright, H., 1982. Deriving the probability density for sums of uniform random variables. Am. Stat. 36, 128–130.
Lutscher, F., 2007. A short note on short dispersal events. Bull. Math. Biol. 69, 1615–1630.
McKay, A.T., 1932. A Bessel function distribution. Biometrika 24, 39–44.
Mistro, D.C., Rodrigues, L.A.D., Ferreira, W.C., 2005. The Africanized honey bee dispersal: a mathematical zoom. Bull. Math. Biol. 67, 281–312.
Mollison, D., 1991. Dependence of epidemic and population velocities on basic parameters. Math. Biosci. 107, 255–287.
Murray, J.D., 1974. Asymptotic Analysis. Oxford University Press, Oxford.
Nathan, R., Perry, G., Cronin, J.T., Strand, A.E., Cain, M.L., 2003. Methods for estimating long-distance dispersal. Oikos 103, 261–273.
Neubert, M.G., Caswell, H., 2000. Demography and dispersal: calculation and sensitivity analysis of invasion speed for structured populations. Ecology 81, 1613–1628.
Neubert, M.G., Parker, I.M., 2004. Projecting rates of spread for invasive species. Risk Anal. 24, 817–831.
Neubert, M.G., Kot, M., Lewis, M.A., 1995. Dispersal and pattern formation in a discrete-time predator–prey model. Theor. Popul. Biol. 48, 7–43.
Okubo, A., 1980. Diffusion and Ecological Problems: Mathematical Models. Springer, Berlin.
Paolella, M.S., 2007. Intermediate Probability: A Computational Approach. Wiley, Chichester.
Petrova, S.S., Solov’ev, A.D., 1997. The origin of the method of steepest descent. Hist. Math. 24, 361–375.
Petrovskii, S.V., Li, B.-L., 2006. Exactly Solvable Models of Biological Invasions. Chapman & Hall/CRC, Boca Raton.
Powell, J.A., Slapnicar, I., van der Werf, W., 2005. Epidemic spread of a lesion-forming plant pathogen—analysis of a mechanistic model with infinite age structure. Linear Algebra Appl. 398, 117–140.
Radcliffe, J., Rass, L., 1997. Discrete time spatial models arising in genetics, evolutionary game theory, and branching processes. Math. Biosci. 140, 101–129.
Reid, N., 1988. Saddlepoint methods and statistical inference. Stat. Sci. 3, 213–227.
Renshaw, E., 2000. Applying the saddlepoint approximation to bivariate stochastic processes. Math. Biosci. 168, 57–75.
Rényi, A., 1970. Probability Theory. North-Holland, Amsterdam.
Shaw, M.W., 1995. Simulation of population expansion and spatial pattern when individual dispersal distributions do not decline exponentially with distance. Proc. R. Soc. Lond. B 259, 243–248.
Shigesada, N., Kawasaki, K., 1997. Biological Invasions: Theory and Practice. Oxford University Press, Oxford.
Shigesada, N., Kawasaki, K., 2002. Invasion and range expansion of species: effects of long-distance dispersal. In J.M. Bullock, R.E. Kenward, R.S. Hails (Eds.) Dispersal Ecology, pp. 350–373. Blackwell, Malden.
Skarpaas, O., Shea, K., 2007. Dispersal patterns, dispersal mechanisms, and invasion wave speeds for invasive thistles. Am. Nat. 170, 421–430.
Skellam, J.G., 1951. Random dispersal in theoretical populations. Biometrika 38, 196–218.
Tufto, J., Ringsby, T.H., Dhondt, A.A., Adriaensen, F., Matthysen, E., 2005. A parametric model for estimation of dispersal patterns applied to five passerine spatially structured populations. Am. Nat. 165, E13–E26.
Weinberger, H.F., 1978. Asymptotic behavior of a model in population genetics. In J. Chadam (Ed.) Nonlinear Partial Differential Equations and Applications, pp. 47–98. Springer, New York.
Weinberger, H.F., 1982. Long-time behavior of a class of biological models. SIAM J. Math. Anal. 13, 353–396.
Willson, M.F., 1992. The ecology of seed dispersal. In M. Fenner (Ed.) Seeds: The Ecology of Regeneration in Plant Communities, pp. 61–85. CAB International, Wallingford.
Zayed, A.I., 1996. Handbook of Function and Generalized Function Transformations. CRC Press, Boca Raton.
Zhang, S., Jin, J., 1996. Computation of Special Functions. Wiley, New York.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kot, M., Neubert, M.G. Saddle-Point Approximations, Integrodifference Equations, and Invasions. Bull. Math. Biol. 70, 1790–1826 (2008). https://doi.org/10.1007/s11538-008-9325-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11538-008-9325-2