Factors Affecting Abundance and Distribution

Abiotic Factors

Abiotic components of an ecosystem comprise the non-living elements such as light intensity, temperature, water availability, wind speed and direction, soil pH and mineral content. These could significantly influence the occurrence and growth of organisms.
Light intensity significantly affects plants as it’s a key requirement for photosynthesis, the process by which green plants manufacture their food. The abundance of photosynthetic organisms like plants and algae is high in areas with good light.
Temperature determines metabolic rates of organisms. Enzyme activity, which drives metabolic processes, is dependent on temperature conditions. More favourable temperature leads to increased organism activity and survival chances.
Water availability is paramount to organisms; it’s required for important biological processes. Organisms in arid regions adapt to conserve water while those in aquatic ecosystems evolve to effectively osmoregulate.
Wind speed and direction affect dispersal and colonization of seeds and spores, also influencing evapotranspiration rates. High wind speeds often limit the height of plants due to physical damage and water loss through transpiration.
Soil pH and mineral content regulate the type of vegetation in a location as different plant species possess unique mineral requirements and pH tolerance levels.

Biotic Factors

Biotic factors are living or previously living organisms which affect the distribution and abundance of species. These include predators, competitors, symbiotic relationships and pathogens.
Predators regulate population size of prey; where predators are abundant, prey species may decrease in number and be restricted to certain areas.
Competition both intra-specific (within the same species) and inter-specific (between different species) for resources (food, water, territory) can influence distribution and abundance.
In symbiotic relationships, changes to one organism directly influences its partner’s distribution. For instance, mutualistic relationships create unique niches for specific species.
The presence of pathogens can limit species. As example, epidemics may reduce the abundance and distribution of susceptible organisms.
Grazing and predation influence the patterns of plant species distribution, with more resilient plant species distributed in areas with high grazing pressure.

Anthropogenic Factors

These are directly or indirectly human-induced changes affecting ecosystem function and biodiversity. It includes habitat loss, pollution, introduction of invasive species, and climate change.
Habitat loss due to urbanization or deforestation can cause drastic reduction in organism abundance and potentially lead to extinction.
Pollution can alter ecosystems drastically; soil, air and water pollutants can destroy habitats and directly harm organisms.
Invasive species alter ecosystems by competing for resources with native species. They often have rapid reproduction rates and lack natural predators, increasing their abundance and distribution.
Climate change alters ecosystem dynamics; changing weather patterns affect the timing of biological activities like migration and breeding, ultimately influencing the distribution and abundance of species.