The only types of land ecosystems which have been changed relatively little are tundra and boreal forests, but climate change has begun to affect them.
(The only types of land ecosystems; have been changed; relatively little) (The only types of land ecosystems which have been changed relatively little; are; tundra and boreal forests) (climate change; has begun; ) (climate change; to affect; them)
The only types of land ecosystems The only types of land ecosystems which have been changed relatively little climate change climate change
have been changed are has begun to affect
relatively little
tundra and boreal forests
them