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We present a detailed analysis of the formation, evolution, and possiblelongevity of metallicity gradients in simulated dwarf galaxies. Specifically,we investigate the role of potentially orbit-changing processes such as radialstellar migration and dynamical heating in shaping or destroying thesegradients. We also consider the influence of the star formation densitythreshold, investigating both a low and high value (0.1 amu/$cm^{3}$ - 100amu/$cm^{3}$).  The Nbody-SPH models that we use to self-consistently form and evolve dwarfgalaxies in isolation show that, in the absence of significant angularmomentum, metallicity gradients are gradually built up during the evolution ofthe dwarf galaxy, by ever more centrally concentrated star formation adding tothe overall gradient. Once formed, they are robust, survive easily in theabsence of external disturbances and hardly decline over several Gyr, and theyagree well with observed metallicity gradients of dwarf galaxies in the LocalGroup. The underlying orbital displacement of stars is quite limited in ourmodels, being of the order of only fractions of the half light radius overtime-spans of 5 to 10 Gyr in all star formation schemes. This is contrary tothe strong radial migration found in massive disc galaxies, caused byscattering of stars off the corotation resonance of spiral structures. In thedwarf regime the stellar body only seems to undergo mild dynamical heating, dueto the lack of long-lived spiral structures and/or discs.  The density threshold has profound influences on the star formation mode ofthe models, but only a minor influence on the evolution of metallicitygradients. Increasing the threshold 1000-fold causes comparatively strongerdynamical heating of the stellar body due to the increased turbulence and thescattering of stars off dense gas clouds, but the effect remains very limitedin absolute terms.

Stellar orbits and the survival of metallicity gradients in simulated dwarf galaxies