Nicholas Lovell and Louise Cox will both be sentence within four weeks.
The public gallery was packed with the victims' family and friends as well as supporters of the pair who entered guilty pleas.
More top news
The future of the nature reserve was in doubt after the local Wildlife Trust was forced to pull out of managing the site.
Traders on Bristol's Park Street have called on landlords to consider the impact of the rents they charge following recent closures.
Bob Crampton with the weather