What are some star constellations that can only be seen from the southern hemisphere?
Out of 88, nearly half. North and South in space are defined with respect to right overhead Earth's North Pole and South Pole directions, respectively. So,South and North are unchanged.
Like Sun, other stars' positions relative to ( Earth;s orbital plane) ecliptic remain almost unchanged, over centuries. The Sun-to- Earth direction rotates about Sun. This enables us to transit 88 constellations in succession, in one year. The transit is noticeable every month, in the celestial East-West-East sense. Of course, southern and northern constellations remain as such. Some stars seen near South-East now would appear near South-West stars, after six months. Polaris near North Pole remains close to the North pole, for ever, For list of South Constellations, see wiki and more.