What will happen to the total biodiversity if grizzly bear becomes extent?

Answer 1

That's a pretty big question and the full answer would be pretty detailed and I'm not sure all the details are known.

One example that comes to mind is that grizzly kills leave food for smaller scavengers, and without that food, their populations might decline. Grizzlies also dig a lot, so they are altering the soil for plants, perhaps in some way we don't know, stopping that will affect plant distribution. Their predation, as all predators, can remove sick or injured animals and helps moderate prey numbers. Since they are not a specialist predator, the effect on each prey species or plant species that they eat will be minor, but the effect still exists.

In short, people fight so hard to prevent extinctions because we often don't make the proper connections between things until the animal is gone and the change can be measured, but by then it's too late.

To give an example, only after reintroducing wolves to Yellowstone National Park did scientists link wolves to song birds. How? They were studying certain types of song birds that nest only along creeks and in certain types of trees (a certain habitat) which was also very popular with elk. The high elk population was eating these tree branches, reducing habitat available for the birds. They then found that when wolves were reintroduced, the elk couldn't stay in one place that long, because wolves would hunt them and make them flee. The elk then spent more time in suitable but less preferred habitat, and the creek trees regenerated naturally, improving song bird nesting.

Another example would be that reducing wolves in the Midwest and eastern US allowed coyotes, originally a southwest animal, to move eastward and northward. They are now in the entire USA but they eat slightly different things. Lack of wolves also allowed deer herds to increase to the point that they caused damage to their own habitat and cause damage to property.

Another thing is that if the grizzly dies then all the food that it ate would start to grow and grow then there would be to many and there wouldn't be enough food and then they would die out. Then it would keep on going.