Do you do anything like this in your area? We have a lake right here in town. After Xmas, the real trees are gathered and put on the lake's ice. When it thaws and falls through, it makes a place for the bass, perch, pike, etc to live.
and then there is this:

FORT LAUDERDALE, Florida (AP) -- Divers began removing up to 2 million old tires from the ocean floor Monday after a plan in the 1970s to create the world's largest artificial tire reef became an ecological disaster.

The well-intentioned idea was to create new marine habitat and alternate dive sites. The plan also served to dispose of tires that were clogging landfills.

But little sea life formed on the tires dumped about a mile offshore in 1972. Some of the bundles bound together with nylon and steel have broken loose and are scouring the ocean floor and washing up on beaches. Others are wedging up against the nearby natural reef, blocking coral growth and devastating marine life.

You'd be surprised how many 'natural' habitats are man made, or at least heavily influenced by man. Huge amounts of moorland (in the UK at least) are only present because of humans grazing sheep on what once would have been deciduous woodland. The Norfolk Broads are a superb landscape too, created mostly by cutting for peat in low lying land, though few seem to know this. Even the oak dominated woodand that is the 'natural' vegetation of most of the country is heavily influenced by human management and are quite different from what they would be if left completely alone.

The sinking of old ships to make marine habitat has a long tradition.

Irrigating of the desert also enhances diverstiy.

The sinking of old ships to make marine habitat has a long tradition.....


We have a some of that in the Great Lakes. But mostly by accident.
It takes a lot of money to sink a ship for a reef the correct way.