Ok i had an island that i inherited from my great grandpa a while back it was barren of animal life with only some sea birds and foliage so i added a small group of american bison to the island. Well then my uncle wish to have this island so he could turn it into a big game hunting preserve, after ordering the animals he realized with a baby on the way he didn’t have time to do this with the island so he pawed it off to my lil. brother. Which was a big mistake as my lil. brother doesn’t know anything bout game other than shoot at the heart and deer is good to eat. He dumped the animals willy nilly round the island, and instead built lodges by the beach so he could have some fun, after some problems with the animals he pawed it off to me. I know the predator/ prey of north america and south america relations but some of these new animals from europe, Asia, Africa, and Australia i have no experience with. So i need some help as most of the species that were on the island have died out. So in less than a years time the island is down to its last survivors and is in chaos.

Ok first there is 6 main environments on the island, ( 5 not including the beaches) in the north there is temperate forest, to the mid west is plains, to the mideast is swamp, to the far south is semiarid desert, and to the the south east there is a 2 mountains that form a valley area ( also on top of the mountains is the only snow found on the island) the island for the most part is semitropical. There is 2 rivers that flow almost all through the island cept for the desert area.
As far as animals these are the fallowing ( cept for some parrots and sea birds)

4 Giraffes ( dwell primarily in the plains)
3 Indian Rhinos ( move constantly through forest, plains, and some times desert)
4 Bison ( after finding the pop. down so much and seeing them struggling to survive in the swamp, i moved them into the Canyon area, they seem to be doing much better there)
21 emu ( seen every where but primarily in the desert area, also they are the only species to actually increase in number from there starting pop.)
4 Fresh water crocs ( live in the swamp and along the rivers)
11 black/white tapirs ( dwell in the swamp, but i am thinking bout moving a small portion to the forest)
7 Desert Bighorn Sheep ( desert area by the mountains, also i believe 3 live in the canyon)
2 China Tigers ( i moved them to the forest after finding caged in a pin on the beach, seem to be getting by)
3 Spotted Hyenas ( desert area, have maintained there starting pop.)
13 Black Bucks ( plains and desert areas)
lastly 11 elk ( live in the plains and forest areas)

Well i need help establishing where to put the animals, and details about the animals. As i am going to try to make this work but if not i will just donate them to a local zoo.

Notes: in the plains black buck and elk seem to herd together
The bighorn sheep and bison are the only animals that fight the hyenas when the hyenas attack
since the bison where moved to the canyon there calves have stopped being taken out by hyenas
the rhinos move loosely in there group of 3, with one walking far ahead of the others is this normal?
the crocs always are seen in pairs is this normal?