This can usually only be resolved through more or less arbitrary judgments: We can identify tundra ecosystems, for example, and measure many of their characteristics, but we must take account of the fact that many of the animals resident on the tundra during the summer are migratory and spend only part of their life cycles there - their arrival brings organic matter "on the hoof" into the tundra ecosystem and their departure takes organic material out of the tundra ecosystem.
(their arrival; brings; organic matter; on the hoof; into the tundra ecosystem) Context(their arrival brings,List([333, 353))):(We; can identify; tundra ecosystems) Context(We can identify their arrival brings,List([76, 353))):(This; can only be resolved; T:usually) (their departure; takes; organic material; out of the tundra ecosystem) (we; must take; account of the fact that many of the animals resident on the tundra during the summer are migratory and spend only part of their life cycles there) (many of the animals resident on the tundra during the summer; are; migratory) (many of the animals resident on the tundra during the summer; spend; only part of their life cycles; L:there)
their arrival brings,List([333, 353)) We can identify their arrival brings,List([76, 353))
their arrival We This their departure we many of the animals resident on the tundra during the summer many of the animals resident on the tundra during the summer
brings can identify can only be resolved takes must take are spend
organic matter on the hoof into the tundra ecosystem
tundra ecosystems
T:usually
organic material out of the tundra ecosystem
account of the fact that many of the animals resident on the tundra during the summer are migratory and spend only part of their life cycles there
migratory
only part of their life cycles L:there