Local volume density ρ₁₀ as a function of the local surface density Σ₁₀. We illustrate the local densities probed by the MATLAS survey with the dwarfs with no HI detection (gray dots). We show the HI-bearing dwarfs divided per morphology: the most gas-rich dIs with M_HI/L_B > 1 (triangles), the dEs (circles), the TTDs (diamonds) and the UDGs (stars). We indicate the gas fraction of the HI-bearing dwarfs with the colorbar.