No; all 'they' need to do is maintain these Scheduled Ancient Monuments. This area is described as one of Dartmoor's 'Premier Archaeological Landscapes' by the Dartmoor National Park Authority.

'The historic environment on Dartmoor is of great importance and value. Much of it is recognised to be of international significance and there are archaeological landscapes that rank amongst the finest in Europe'

http://www.dartmoor-npa.gov.uk/index/lookingafter/laf-landmanagement/laf-moorfutures/premier_archaeological_landscapes.htm

And then there's this (under the heading of 'Dartmoor’s unique combination of natural and cultural assets'

The gems of the rich cultural landscape are the archaeological features documenting human presence and activity stretching back almost 6,000 years. Over 6% of England’s scheduled monuments are to be found on
Dartmoor, and include one of the finest collections of Bronze Age settlements and ceremonial monuments in Europe.

Such features require management if they are to remain accessible
and protected from damage caused by inappropriate vegetation
including gorse, bracken and scrub.

http://www.dartmoor-npa.gov.uk/dartmoor_vision_leaflet_april_2008.pdf

Management....aka responsibility....

Peace

Pilgrim

X