I think it's a wrong assumption to make that every Sylvari is inherently in symbiosis with nature or that Asura are not. Take Canach or Scarlet for example; they have no more inherent connection with nature than what they're made of. And if your train of thought stems from the fact that they're made of plant cells, then you must also consider that the other races are made of animal cells, and animals and plants are just as relevant to nature. If anything, I just recall Sylvari being especially good at plantshaping, which they used to form The Grove and their houses, but their bond with the fauna seems to me is lesser than that of Charr, Norns, or Humans. And in tems of Asura rangers, I see them as herbology specialists who have expert knowledge on the taxonomy of any plant and animal