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Parasite can alter the dynamics and diversity of competitive communities indirectly. Here, we firstly constructed a cyclic competition system with three species mediated by a free-living parasite. Subsequently, we explored the effects of parasite traits on the transient dynamics of three host species, as well as the stability and species richness of the competitive community at different time-scales. Simulation results reveal that the invasion of parasite is a key factor in inducing the community unstability. Parasite traits and interspecific competition are likely crucial in structuring communities and disease dynamics. In particularly, parasite invasion can transform the classically periodic oscillation of cyclic community into more complex dynamics, such as periodic oscillation of the community at a large time scale, and periodic oscillation of a single species at a small time scale. Additionally, analysis of the autocorrelation function and partial autocorrelation function analysis for time series of species’ biomass in the cyclic competition system indicate that the time series of species’ biomass at both large and small time scales are stationary. Furthermore, as parasites invade the initial stage equilibrium dynamics of cyclic competition system, pathogenic infection can induce to the extinction of two species, leaving only one species to persist and undergo periodic oscillation. In cases of initial local stability, pathogenic infection can cause all three species to undergo periodic oscillation coincidently. Moreover, the observed transient dynamics of cyclic communities, including the timing of sudden switches in dynamics and other characteristics of transients, occur during the process of parasite invasion. Finally, three parasite traits (transmission rate, shedding rate and virulence) can alter the periodicity and corresponding species richness of cyclic competition. In short, parasite invasion can dramatically change community stability and species diversity. [ABSTRACT FROM AUTHOR]

The theory of large orebodies hosted in small intrusion emphasizes the relation between the geometrical scale of a magmatic intrusion and the efficiency of endogenic metallic mineralization. However, the essence of this relation is poorly understood till now. The basic problems related to the magma metallogenic system were briefly analyzed, and the intrinsic relations between the geometrical scale of an intrusion and several key factors controlling mineralization were focused. The published functional relation between the cooling duration and the migrating distance of solidus front in a magmatic intrusion was used to estimate the solidification time-scale of a magmatic intrusion. It is found that the living time-scale of the small intrusion is consistent with the time-scale required for forming a super-giant deposit. Based on Stock's Law, the simulation suggests that the small intrusions containing melano-microgranular enclaves are characterized by rapid ascending of magma, which is consistent with the experimental observations showing positive relation of the fluid solubility of ore-forming metal to its pressure (P) and temperature (T). The relations of the magma production to the source decompression rate and the volatile concentration in the produced magma were analyzed. Accordingly, it is proposed that the magma production followed a huge volume of magmatism must decrease, and hence the ratio of fluid and melt increases gradually. Therefore, it is helieved that a super-giant deposit can form immediately behind the extensive magmatism, and such a metallogenic process can be called as the post-batholith metallogenesis, taking the felsic magma metallogenic system as an example. In general, it is concluded that the scale effect of the magma metallogenic system is an important geological effect, and the analysis of scale effect supports the theory of giant deposit mineralized by the small intrusion. [ABSTRACT FROM AUTHOR]