Galaxies in the local universe can be viewed as complex ecosystems in which energy flows and matter cycles are regulated by internal processes and environmental effects. Investigating the ISM, star formation, and quenching mechanisms is essential for a comprehensive understanding of the regulation and evolution of galaxy ecosystems. In this talk, I will highlight our statistical results derived from extensive multi-wavelength surveys of local galaxies. Our analysis reveals that central disk galaxies with star formation rates significantly below the star-forming main sequence unexpectedly possess HI gas reservoirs comparable to those of star-forming galaxies, but exhibit substantially lower molecular gas content and star formation efficiency. We further demonstrate that quenching in these central disk galaxies is closely linked to bulge growth, bar-driven activity, and feedback from low-luminosity AGN. These results lead to a coherent picture of how internal “mass quenching” operates. Additionally, we find that the residual HI gas content provides a robust diagnostic for distinguishing between internally driven and environmentally driven quenching pathways in satellite galaxies. Finally, I will present our latest insights into the star formation law, derived from studies of dust properties in the local galaxy population.