I like your separation of foreground/background and the composition feels quite good. As Mike said, the foreground intrudes into the scene a bit much, distracting from the characters. I would remove the fence, or change it as it is distracting as is (is it barbed wire, electric?). Although it's a thumbnail, it should be clear what it is or removed if not necessary at this stage. I guess the main thing that jumps at me is 'why?' Why is the salamander running away and why is the squirrel dangerous? Difficult to answer in a drawing but it's not self-evident, so you really need to make the characters very dynamic in appearance and action to demonstrate why it's happening.

I like the depth you've created with the foreground, mid and background. But the focus of this whole composition is not the squirrel or the salamander. I agree with what Mike Karcz said about the position and posture of the animals as well. Great concept, great depth, just adjust your composition to suit the concept more. Remove anything that doesn't server the purpose of the chase.

I think the salamander is static in its pose. I like the squirrel's pose, but it doesn't convey that the squirrel is chasing the salamander. I think the poses need to be reworked to show them in the action of the case - the salamander should RUSHING forward and the squirrel should be LAUNCHING after it. There's a sign that says "beware of squirrel". I'd like to see the squirrel take on a menacing pose and the salamander tripping over itself desperate to get away. I like the foliage in the foreground, but the leaves in the center take up a third of the frame and distracts from the the two main subjects, the salamander and the squirrel. Otherwise, I like the composition a lot. I hope this is helpful!