Some landlords will not take long term rentals, due to the problems one can have getting a bad tennant to vacate.

Time of let is inmaterial, it is the wording of the contract, if it is not correct the tennant can stay for five years if they want to and pay their rent on time.

Just looking at options...

So they'd rather take short term lets, doesn't make sense - they need to get the money from somewhere?
...or is there a scheme set up to protect tenants in Spain?

That is my point. Even if tennant does not pay the rent and trashes the property it can be very difficult and expensive to get them out. Some LL do not wish to expose themselves to the risk and feel safer with holiday lets.

It can be very hard to find "reasonable" long term rentals so you should get in contact with someone who has a lot of them on their books.

You should also consider that unless you live in a town center and car is a must, yes it's a small island (45km) but taxis are expensive and as someone else pointed out, busses are not that frequent. There are hundreds of foreign cars here especially in the summer months so bring your own if you can.

You can expect to pay 800 -1200€ a month for 2 bedrooms and shared pool, long term...houses are more.