This paper formulates and analyzes a stochastic predator-prey model focusing on the elk–wolf dynamics. The mathematical framework is motivated by the Banff–Bow Valley ecosystem, where the elk population is categorized into urban and valley subgroups, both subject to wolf predation. We extend the deterministic interaction model into a system of stochastic differential equations to incorporate environmental fluctuations. The global existence and uniqueness of positive solutions are established, ensuring the biological realism of the model. By applying logarithmic Itô calculus and Lyapunov function techniques, we derive explicit extinction criteria and prove moment as well as ultimate boundedness properties of the populations. Moreover, we introduce a practical parameter-based stochastic threshold that characterizes predator persistence and stochastic permanence, highlighting qualitative differences between deterministic coexistence and noise-induced extinction. Finally, numerical simulations based on the Euler–Maruyama scheme are provided to illustrate the theoretical results and confirm the predicted long-term stochastic behaviors.
Citation: Yousef Alnafisah, Moustafa El-Shahed. Stochastic dynamics of an elk–wolf system with inter-regional movement[J]. AIMS Mathematics, 2026, 11(3): 6400-6419. doi: 10.3934/math.2026264
This paper formulates and analyzes a stochastic predator-prey model focusing on the elk–wolf dynamics. The mathematical framework is motivated by the Banff–Bow Valley ecosystem, where the elk population is categorized into urban and valley subgroups, both subject to wolf predation. We extend the deterministic interaction model into a system of stochastic differential equations to incorporate environmental fluctuations. The global existence and uniqueness of positive solutions are established, ensuring the biological realism of the model. By applying logarithmic Itô calculus and Lyapunov function techniques, we derive explicit extinction criteria and prove moment as well as ultimate boundedness properties of the populations. Moreover, we introduce a practical parameter-based stochastic threshold that characterizes predator persistence and stochastic permanence, highlighting qualitative differences between deterministic coexistence and noise-induced extinction. Finally, numerical simulations based on the Euler–Maruyama scheme are provided to illustrate the theoretical results and confirm the predicted long-term stochastic behaviors.
| [1] | L. Dickmeyer, The Banff–Bow Valley: environmental conflict, wildlife management and movement, Ph.D. thesis, University of British Columbia, 2009. https://dx.doi.org/10.14288/1.0070842 |
| [2] |
L. J. Koetke, A. Duarte, F. W. Weckerly, Elk population dynamics when carrying capacities vary within and among herds, Sci. Rep., 10 (2020), 15956. https://doi.org/10.1038/s41598-020-72843-5 doi: 10.1038/s41598-020-72843-5
|
| [3] |
J. F. Goldberg, M. Hebblewhite, J. Bardsley, Consequences of a refuge for the predator–prey dynamics of a wolf–elk system in Banff National Park, Canada, PLoS One, 9 (2014), e91417. https://doi.org/10.1371/journal.pone.0091417 doi: 10.1371/journal.pone.0091417
|
| [4] |
M. Maji, M. Kumar, S. Khajanchi, D. Ghosh, Persistence and extinction in an elk–wolf prey–predator system with refuge and inter-regional movement, Appl. Math. Comput., 514 (2026), 129834. https://doi.org/10.1016/j.amc.2024.129834 doi: 10.1016/j.amc.2024.129834
|
| [5] |
X. Dai, H. Jiao, J. Jiao, Q. Quan, Survival analysis of a predator–prey model with seasonal migration of prey populations between breeding and non-breeding regions, Mathematics, 11 (2023), 3838. https://doi.org/10.3390/math11183838 doi: 10.3390/math11183838
|
| [6] |
J. Alebraheem, T. Q. Ibrahim, G. E. Arif, A. A. Hamdi, O. Bazighifan, A. H. Ali, The stabilizing effect of small prey immigration on competitive predator–prey dynamics, Math. Comp. Model. Dyn., 30 (2024), 605–625. https://doi.org/10.1080/13873954.2024.2366337 doi: 10.1080/13873954.2024.2366337
|
| [7] |
P. K. Tiwari, M. Verma, S. Pal, Y. Kang, A. K. Misra, A delay nonautonomous predator–prey model for the effects of fear, refuge and hunting cooperation, J. Biol. Syst., 29 (2021), 927–969. https://doi.org/10.1142/S0218339021500236 doi: 10.1142/S0218339021500236
|
| [8] | C. S. Shekar, V. Anand, C. N. Anuradha, B. H. Prasad, Mathematical study on immigration and migration of a prey–predator ecosystem with unlimited resources for the predator, Indian J. Sci. Technol., 18 (2025), 2569–2580. |
| [9] |
X. Y. Meng, X. Z. Sun, Dynamics of a stage-structure diffusive predator–prey model with nonlinear prey refuge, delay and anti-predator behavior, Int. J. Appl. Comput. Math., 12 (2026), 2. https://doi.org/10.1007/s40819-025-02077-4 doi: 10.1007/s40819-025-02077-4
|
| [10] |
C. Talapatra, Stochastic dynamics of dual-prey–predator interactions under harvesting pressure: Insights from the California current ecosystem, Earthline J. Math. Sci., 15 (2025), 989–1020. https://doi.org/10.34198/ejms.15625.9891020 doi: 10.34198/ejms.15625.9891020
|
| [11] |
T. J. Clark, J. S. Horne, M. Hebblewhite, A. D. Luis, Stochastic predation exposes prey to predator pits and local extinction, Oikos, 130 (2021), 300–309. https://doi.org/10.1111/oik.07381 doi: 10.1111/oik.07381
|
| [12] |
M. Liu, K. Wang, Q. Wu, Survival analysis of stochastic competitive models in a polluted environment and stochastic competitive exclusion principle, B. Math. Biol., 73 (2011), 1969–2012. https://doi.org/10.1007/s11538-010-9569-5 doi: 10.1007/s11538-010-9569-5
|
| [13] |
S. Salman, A. Yousef, A. Elsadany, Dynamic behavior and bifurcation analysis of a deterministic and stochastic coupled logistic map system, Int. J. Dynam. Control, 10 (2022), 69–85. https://doi.org/10.1007/s40435-021-00795-3 doi: 10.1007/s40435-021-00795-3
|
| [14] |
Y. Tian, J. Zhu, J. Zheng, K. Sun, Modeling and analysis of a prey–predator system with prey habitat selection in an environment subject to stochastic disturbances, Electron. Res. Arch., 33 (2025), 744–767. https://doi.org/10.3934/era.2025034 doi: 10.3934/era.2025034
|
| [15] |
S. Helali, D. Laribi, H. B. Fredj, Two-prey predator model with Holling type-Ⅱ functional response and multiple delays: Hopf-bifurcation analysis, parameters estimation, and capture prediction, J. Appl. Math. Comput., 71 (2025), 7691–7724. https://doi.org/10.1007/s12190-025-02544-7 doi: 10.1007/s12190-025-02544-7
|
| [16] |
Y. Zhang, F. Lai, S. Gao, Y. Liu, S. Yan, Dynamical analysis of a stochastic prey–predator model with fear effect and feedback control, J. Biol. Dynam., 19 (2025), 2479461. https://doi.org/10.1080/17513758.2025.2479461 doi: 10.1080/17513758.2025.2479461
|
| [17] |
E. E. Brandell, P. C. Cross, D. W. Smith, W. Rogers, N. L. Galloway, D. R. MacNulty, et al., Examination of the interaction between age-specific predation and chronic disease in the Greater Yellowstone ecosystem, J. Anim. Ecol., 91 (2022), 1373–1384. https://doi.org/10.1111/1365-2656.13661 doi: 10.1111/1365-2656.13661
|
| [18] | X. Mao, Stochastic differential equations and applications, Amsterdam: Elsevier, 2007. |
| [19] | R. Khasminskii, Stochastic stability of differential equations, Berlin: Springer, 2011. https://doi.org/10.1007/978-3-642-23280-0 |
| [20] |
G. Lan, S. Yuan, B. Song, The impact of hospital resources and environmental perturbations to the dynamics of SIRS model, J. Franklin I., 358 (2021), 2405–2433. https://doi.org/10.1016/j.jfranklin.2021.01.015 doi: 10.1016/j.jfranklin.2021.01.015
|
| [21] |
T. Caraballo, P. E. Kloeden, The persistence of synchronization under environmental noise, P. Roy. Soc. A, 461 (2005), 2257–2267. https://doi.org/10.1098/rspa.2005.1484 doi: 10.1098/rspa.2005.1484
|
| [22] |
C. Ji, D. Jiang, H. Liu, Q. Yang, Existence, uniqueness and ergodicity of positive solution of mutualism system with stochastic perturbation, Math. Probl. Eng., 2010 (2010), 684926. https://doi.org/10.1155/2010/684926 doi: 10.1155/2010/684926
|
| [23] |
Z. Xu, L. Wang, Stationary distribution and extinction of a stochastic SEI epidemic model with logistic growth and nonlinear perturbation, AIMS Math., 10 (2025), 28488–28513. https://doi.org/10.3934/math.20251254 doi: 10.3934/math.20251254
|
| [24] |
M. S. Boyce, Wolves for Yellowstone: Dynamics in time and space, J. Mammal., 99 (2018), 1021–1031. https://doi.org/10.1093/jmammal/gyy115 doi: 10.1093/jmammal/gyy115
|
| [25] |
G. Zhang, Y. Shen, B. Chen, Positive periodic solutions in a non-selective harvesting predator–prey model with multiple delays, J. Math. Anal. Appl., 395 (2012), 298–306. https://doi.org/10.1016/j.jmaa.2012.05.045 doi: 10.1016/j.jmaa.2012.05.045
|