Stable Coexistence in a Field-Calibrated Individual-Based Model of Mangrove Forest Dynamics Caused by Inter-Specific Crown Plasticity

(1,2) In this theoretical study, we apply MesoFON, a field-calibrated individual-based model of mangrove forest dynamics, and its Lotka–Volterra interpretations to address two questions: (a) Do the dynamics of two identical red mangrove species that compete for light resources and avoid inter-specific competition by lateral crown displacement follow the predictions of classical competition theory or resource competition theory? (b) Which mechanisms drive the dynamics in the presence of inter-specific crown plasticity when local competition is combined with global or with localized seed dispersal? (3) In qualitative support of classical competition theory, the two species can stably coexist within MesoFON. However, the total standing stock at equilibrium matched the carrying capacity of the single species. Therefore, a “non-overyielding” Lotka–Volterra model rather than the classic one approximated best the observed behavior. Mechanistically, inter-specific crown plasticity moved heterospecific trees apart and pushed conspecifics together. Despite local competition, the community exhibited mean-field dynamics with global dispersal. In comparison, localized dispersal slowed down the dynamics by diminishing the strength of intra-/inter-specific competition and their difference due to a restriction in the competitive race to the mean-field that prevails between conspecific clusters. (4) As the outcome in field-calibrated IBMs is mediated by the competition for resources, we conclude that classical competition mechanisms can override those of resource competition, and more species are likely to successfully coexist within communities.

Zjišťování průběhu změn teploty sněhu v běžecké stopě

Friction of pair of skis increases the temperature of the snow in the skiing track.Th is temperature is connected with the use of specifi c wax in rising tube in the ski for classic. Th e main aim of our thesis is to fi nd out with a help of infrared thermography if the change of this temperature of skiing track before and aft er passage of the team of skiers is so important that it can infl uence service of skies for competition reasons. To fi nd out the changes of snow temperature in the skiing track we have used thermographical system FLIR SC 620 with frequency sampling of 30Hz.Th is system was used aft er passage of a group of 11 skiers. Signifi cant continual increase of snow temperature has been indicated when group of skiiers passed (0,87±0,153 °C) and decrease to original level 10 - 30 seconds aft er passage of skiers. Flat dynamic thermography could help, on given conditions, for ”correction” of tactic in classical competition with collective start and also when choosing correct wax. In order to be able to get more signifi cant fi ndings it is neccessary to make repeated observations on conditions that are similar to real competition or right during classical competition with the skiing track on plain or ascending surface.