an increase in the spider population
There are many contributing factors that could be the cause for a decrease in fox population. Over population, not enough food, disease, or over hunting or poaching any of these could be the reason for a decrease in the population.
the cause of the insect population increasing is that the animals are becoming extinct.
A sudden decrease in the butterfly population would cause a corresponding decrease in the chameleon population since they no longer have enough food.
What will cause a decline in the human population is loss of fish, dirty water, a whole in the ozone layer. These are just three causes that could decrease mankind.
deforestization or the destruction of owl habitats could cause a decrease in an owl population. This would then mean the owls prey, such as a field mouse, would flourish and increase in population.
Death and migration are factors that can decrease hare population.
i do not know this sorry not
A natural cause of decline in a population could be disease outbreak or an epidemic. Diseases can spread rapidly through a population, resulting in a significant decrease in the number of individuals. This decline in population can occur in both plants and animal species.
there would be less nutrients for the plant.
the climate
the climate