The climate at the equator is warm, moist and either desert or rain-forest. The rain forest biome has been noted to have the greatest amount of biodiversity in an ecosystem. Resources are abundant both in food sources and in shelter sources because the rain forest has both a tertiary shelter system and a vertical shelter system. Water is abundant and therefore not a limiting factor, food is abundant and does not depend on a climate induced growing season. Many types of animal and plant life cohabit the same area. Predator and prey animals flourish in the rain forest biome which is typically located in equatorial regions. In the oceans, the equator is where the cold ocean currents are warmed and begin the warm water return conveyor toward the polar regions. Ocean life in the equatorial waters is equally varied as that on land. Many coral reefs are located in equatorial waters and form barrier islands that protect mainlands from hurricane force winds and waves.
Water is a limiting factor near the equator in desert biomes, and water is a limiting factor in arctic biomes as it is frequently found in the form of ice and not usable for consumption by animals. Temperature is another limiting factor. In desert biomes, water is simply not available. In temperate biomes, water may be abundant and therefore not a limiting factor. Food may be a limiting factor the further away from the equator one travels as the growing seasons are shortened for the producers (plant life) and therefore limit the number of prey species a geographical area may support.
The further away from the number one life source of solar energy, the more energy it costs or requires to live in cooler areas. So, it is a cost/benefit relationship for an animal to move to a cooler area. Is the energy spent worth the available food in order to live in an area. (Animals do not have the ability to rationalize in this manner.)
Buffer zones or greenways are used to help animal life and plant life remain interconnected, safe from human encroachment, and safe from poaching. Inbreeding in some tiger and lion groups due to isolation has resulted in some severe genetic problems that threaten the populations in those areas. Having a green zone where the animal life can continue to live and intermix allows for continued biodiversity while allowing the animals to interbreed with groups other immediate offspring or sibling individuals. Biodiversity is preserved as green areas are protected from development and industry