I think you can see that each riser has two small (LED) lights. Late winter I noticed that one of the lights in the lowest riser was out. After much trouble it was determined that the hidden low voltage wire behind the stair had been chewed through. It has been repaired but I am now mulling over how best to seal up that front edge ("highlighted" in blue).

One option I think would be to dig out a few inches in front of that lowest riser and put in small size river rock or pea gravel?

Or I guess dig out in front and insert a narrow strip of metal mesh e.g. "chicken wire"?

What do you think?

As you might imagine this deck is reasonably large and I don't envision doing this work around the base of the whole perimeter but I am convinced that these two particular lights are the most susceptible as the wiring for them is closest to the ground and the rodents are more likely to gnaw here as there is obvious signs of entry and egress right out on that front edge.