  M-dwarf stars are prime targets for exoplanet searches because of their close
proximity and favorable properties for both planet detection and
characterization. However, the potential habitability and atmospheric
characterization of these exoplanetary systems depends critically on the
history of high-energy stellar radiation from X-rays to NUV, which drive
atmospheric mass loss and photochemistry in the planetary atmospheres. With the
Far Ultraviolet M-dwarf Evolution Survey (FUMES) we have assessed the evolution
of the FUV radiation, specifically 8 prominent emission lines, including
Ly$\alpha$, of M-dwarf stars with stellar rotation period and age. We
demonstrate tight power-law correlations between the spectroscopic FUV
features, and measure the intrinsic scatter of the quiescent FUV emissions. The
luminosity evolution with rotation of these spectroscopic features is well
described by a broken power-law, saturated for fast rotators, and decaying with
increasing Rossby number, with a typical power-law slope of $-2$, although
likely shallower for Ly$\alpha$. Our regression fits enable FUV emission line
luminosity estimates relative to bolometric from known rotation periods to
within $\sim$0.3 dex, across 8 distinct UV emission lines, with possible trends
in the fit parameters as a function of source layer in the stellar atmosphere.
Our detailed analysis of the UV luminosity evolution with age further shows
that habitable zone planets orbiting lower-mass stars experience much greater
high-energy radiative exposure relative the same planets orbiting more massive
hosts. Around early-to-mid M-dwarfs these exoplanets, at field ages, accumulate
up to 10-20$\times$ more EUV energy relative to modern Earth. Moreover, the
bulk of this UV exposure likely takes place within the first Gyr of the stellar
lifetime.
