The carrying capacity of any individual biological species is the maximum size of the population which can sustain indefinitely in that environment provided the necessary requirements like food, water and other environmental conditions are available.
If the area is increased, the carrying capacity is likely to increase for the rodents.
When the number of individuals within a group or population or species suddenly decline it is termed as population crash. The other major reason can be any natural disaster like floods, droughts, earthquake, volcanic eruption, fire, incidence of some disease or epidemic condition.
During summer, when the disease starts killing individuals, the carrying capacity will decrease.
