@Agni3 - Becoming a naturalist is more than a job; it is a work of love. Certainly, there are many professions where the pay is better and there is air conditioning all summer long; but the fact is that those of us who love nature usually aren’t too concerned about either of those things.
There are many reasons to go into this particular profession, but it is not a glamorous job in the least. It can often be combined with something equally nature related, such as forestry.
People who have a love of the wild and a love of teaching others about it will be quite interested to pursue this kind of position, I think. However, in all honesty, I don't know if even the presidency is recession proof anymore.