Archaeologist Lewis Borck, PhD, would answer: quite a lot.
"Disturbance" describes an archaeological site that has been altered by either natural forces (erosion, animal activity, etc.), previous archaeological excavations, or - as is often the case these days - by vandalism or looting as shown in the photos. Dr. Borck explained in an article he wrote for the Fall 2019 issue of American Archaeology (Vol. 23 No. 3 at p. 44) that his research as a preservation archaeologist focuses upon disturbed sites rather than sites that may be more intact. He says, in part,
"...I view this as a form of historical reparations because it is respecting the wishes of descendant groups to minimize the impact to intact archaeological sites....I also view it as historical reparations because we are demonstrating that there is a ton of data you can get out of these looted sites, and it's our responsibility to recover as much as possible....It's also a form of landscape reparations, because we fill in the sites so that they don't look damaged afterwards."
Generally, Dr. Borck examines and sets aside any looted debris from a site, then proceeds to excavate, map, and date the remaining archaeological structures and features. He believes archaeologists should not dismiss disturbed sites as too difficult to interpret because - especially with current scientific technology - there is still abundant archaeological data to retrieve. These data can be applied to the findings from numerous other sites to gain a more detailed and comprehensive understanding of ancient regional settlement patterns, land use, and cultural identities.
To read more of Dr. Borck's published work and the perspective he brings to his research, start here.
/s/ webmaster [all photos courtesy of M.Smith, GCAS]