The sunlight decides the amount of biodiversity present in the world. We can simply see that equatorial and tropical areas have more biodiversity than colder regions in the world. These areas attract flora and fauna due to high availability of food, water and warmth. But the region was not attractive to species during pre-historic periods.
The dinosaurs stayed away from this part of the globe. Once most dominant species on the Earth had different preferences about the habitats. The creatures avoided to settle on the Equator, the most biologically rich region now. The southern and northern region around the equator was more populated by dinosaurs during division of supercontinent Pangaea till the Triassic period. Jessica Whiteside, Lead author of the study informed that big vegetarian dinosaurs had more population located around higher latitudes during the Triassic period. The fact was hidden from scientists from a long time. Small carnivorous group of dinosaurs preferred to stay around tropical region and equator. Even majority of dinosaur fossils are missing during the excavations in area for last 10 years.
She is paleoclimatologist at University of Southampton. The warm blooded vegetarian species require continuous supply of green leave which was missing around tropics due to fast climate changes, dynamics of drought and higher temperature at the equator that time. This pushed these creatures away from the equator and looks like the earth is going through similar conditions now as global warming is heating the equator now. There is strong connection between migration patterns of dinosaurs and climate change.