What are the themes of competitions that have corresponding host cities with more than 1000 residents?
SELECT T2.Theme FROM city AS T1 JOIN farm_competition AS T2 ON T1.City_ID  =  T2.Host_city_ID WHERE T1.Population  >  1000
1000'den fazla sakini olan karşılık gelen ev sahibi şehirlere sahip yarışmaların temaları nelerdir?