  We study the properties of dark matter haloes of a LCDM model in different
environments. Using the distance of the 5th nearest neighbour as an
environmental density indicator, we show that haloes in a high density
environment are more massive, richer, have larger radii and larger velocity
dispersions than haloes in a low density environment. Haloes in high density
regions move with larger velocities, and are more spherical than haloes in low
density regions. In addition, low mass haloes in the vicinity of the most
massive haloes are themselves more massive, larger, and have larger rms
velocities and larger 3D velocities than low mass haloes far from massive
haloes. The velocities of low mass haloes near massive haloes increase with the
parent halo mass. Our results are in agreement with recent findings about
environmental effects for groups and clusters of galaxies from deep (SDSS and
LCRS) surveys.
