A limiting factor is any factor that limits the growth of a population by restricting the resources or conditions available. Limiting factors stop populations growing indefinitely and determine the carrying capacity.Limiting factors can be abiotic (non-living) or biotic (living).Abiotic limiting factors include:• temperature: affects enzyme activity and metabolic rate, especially in ectotherms
• light intensity: limits the rate of photosynthesis and therefore plant growth
• water and humidity: water is needed by all organisms; too little limits plant growth
• pH: affects enzyme activity and nutrient availability in soil and water
• oxygen availability: important in aquatic habitats and waterlogged soils
• availability of minerals such as nitrates and phosphates for plantsBiotic limiting factors include:• food supply
• predation
• disease and parasites
• competition, both interspecific (between species) and intraspecific (within a species), for food, space, light, mates or nesting sites.Usually one factor is in shortest supply at any one time, and this is the factor that controls the population size. For example, if a plant population has plenty of water and nutrients but grows under a dense tree canopy, light is the limiting factor. Improving the limiting factor increases the population until another factor becomes limiting.Example: a population of trout in a warm, slow river may be limited by low dissolved oxygen, even if food is abundant.
• light intensity: limits the rate of photosynthesis and therefore plant growth
• water and humidity: water is needed by all organisms; too little limits plant growth
• pH: affects enzyme activity and nutrient availability in soil and water
• oxygen availability: important in aquatic habitats and waterlogged soils
• availability of minerals such as nitrates and phosphates for plantsBiotic limiting factors include:• food supply
• predation
• disease and parasites
• competition, both interspecific (between species) and intraspecific (within a species), for food, space, light, mates or nesting sites.Usually one factor is in shortest supply at any one time, and this is the factor that controls the population size. For example, if a plant population has plenty of water and nutrients but grows under a dense tree canopy, light is the limiting factor. Improving the limiting factor increases the population until another factor becomes limiting.Example: a population of trout in a warm, slow river may be limited by low dissolved oxygen, even if food is abundant.