Not sure if this helps, but Brandon Sanderson's Mistborn Series takes place on a planet with heavy, nigh-perpetual ash-fall. The characters learned that they used to be on an Earth-like planet, but after a catastrophe:
Plants all turned brownish colors and no longer flowered as long or as much (if at all).
Species started having way more children, I think. Besides whatever the LR did to the Skaa, Tensoon mentions that the older generations of Kandra are fewer in number than the younger ones, despite Gen 1 and Gen 2 basically staying in the Homeland and never taking Contracts.
I think there were less birds and fish?
Vin grew up in Luthadel, but she and Reen traveled a bit as kids. I
don't recall an instance where she mentioned or thought about how,
when things were desperate, she'd catch pigeons/fish/stray
animals/rats for food. I also cannot remember her ever mentioning
seeing birds or fish, and birds are pretty common in urban areas. I also cannot recall her mentioning eating poultry or seafood at any of the balls, though that may just be my memory failing me.
Beyond that, birds would either need to preen way more often to get
ash out of their feathers or they'd become unable to fly due to
issues with balance and weight if the ash got stuck. (There's some cool and kinda sad stuff about how important it is for birds to keep clean, if you want to look it up.) And fish could quite possibly get ash stuck in their gills and suffocate- it happens with sediment from river bottoms sometimes.
It's also entirely possible that, as crops failed and food became an
issue around when the LR took over, people hunted a lot of animals
In book three, the characters were looking for food sources and
someone mentioned growing fungi to combat the food problem. This is
an idea that I think would make sense as fungi can be grown
indoors/away from the ash.
Of course the story is fantasy, so I'm not sure how accurate this is.
Your planet has to deal with lots of tectonic activity too, so there'd be issues with anything underground. Food caches, power lines, sewers? Animal burrows, water, food caches? Nope, that earthquake just sealed off the area/released toxic gasses/crushed everything so no one could recognize the area. (And, assuming you mean hot/sandy desert, filled the place with sand, too.) Ooh, and sinkholes are a thing. Yeah...
Speaking of the Mistborn, the high volcanic activity would probably block out sunlight for most of the day/week/month with ash- if it ever clears up. This could, eventually, lead to your planet becoming a snowball.