Appalling! The report does not make the above statement anywhere. The report states quite clearly at the beginning:

It is not appropriate to compare indicator trends between countries as data from different taxonomic groups have been used.

Fergal has done just that. Mendacious or stupid or both?

Looking more deeply into the report we find that you can meaningfully compare the figures for some species but that these are favourable to Scotland:

Trends do vary across the UK countries and generally farmland birds are faring better in Scotland , where on average they have increased since the 1990s.

, where on average they have increased since the 1990s. Our State of Nature metrics show declines in moths and butterflies across the UK, although trends in Scotland are, on average, stable .

. Declines have been most notable in breeding waders of lowland wet grassland such as Lapwing and Snipe, due to habitat loss. Outside Scotland, a large proportion of these species’ populations are now confined to sites managed as nature reserves .

. UK woodland cover increased by 9% between 1998 and 2018 and is currently estimated at 3.17 million ha. Scotland has seen the largest area increase (156,000ha)

(156,000ha) Pressure on Scotland’s diverse landscapes has resulted in biodiversity losses and gains. There is evidence that some wildlife has fared better in Scotland over recent decades than in the UK as a whole.

https://nbn.org.uk/wp-content/uploads/2019/09/State-of-Nature-2019-UK-full-report.pdf