How do environmental changes such as temperature, availability of water, and the composition of atmospheric gases impact the distribution of species in an ecosystem?

Sourav PanNovember 12, 2024

Answered

Environmental changes, such as variations in temperature, availability of water, and the composition of atmospheric gases, significantly impact the distribution of species in ecosystems. Here’s how these factors influence species distribution and the implications for biodiversity and ecosystem dynamics:

1. Temperature Changes

• Range Shifts: As temperatures increase due to climate change, many species are shifting their geographic ranges toward cooler areas, such as higher latitudes or elevations. For instance, land animals in North America have been observed moving northward by an average of 3.8 miles per decade, while some marine species have shifted north by more than 17 miles per decade . This movement is often driven by the need for suitable habitat conditions that meet their physiological needs.
• Metabolic Effects: Warmer temperatures can increase metabolic rates in organisms, leading to higher energy demands. For example, fish and other aquatic organisms may experience increased oxygen demand in warmer waters, which can affect their growth and reproduction. Species unable to adapt to these changes may face population declines or extinction.

2. Availability of Water

• Drought and Water Stress: Changes in precipitation patterns can lead to drought conditions, reducing water availability for plants and animals. Plants may experience stress during dry periods, affecting their growth and ability to photosynthesize. This can lead to shifts in plant communities and subsequently impact herbivores that rely on these plants for food .
• Aquatic Ecosystems: In freshwater systems, reduced water levels can lead to habitat loss for aquatic species. As water bodies shrink or become more saline due to evaporation or saltwater intrusion, sensitive species may be forced to relocate or may not survive .

3. Composition of Atmospheric Gases

• Increased Carbon Dioxide Levels: Higher levels of atmospheric CO₂ can enhance plant growth through increased photosynthesis; however, this effect can be offset by other stressors such as nutrient limitations and water scarcity . Moreover, elevated CO₂ levels may favor certain plant species over others, potentially leading to shifts in community composition.
• Oxygen Availability: In aquatic environments, warmer waters hold less dissolved oxygen, which can create hypoxic (low oxygen) conditions detrimental to fish and other marine organisms . Species that cannot tolerate low oxygen levels may decline or disappear from affected areas.

4. Interactions Among Species

• Changes in Food Webs: Alterations in temperature and water availability can disrupt the timing of natural events (phenology), such as flowering or migration. For example, if plankton blooms occur earlier due to warming temperatures but fish spawn at the same time each year, young fish may find insufficient food when they need it most . Such mismatches can have cascading effects throughout the food web.
• Invasive Species: Environmental changes can facilitate the spread of invasive species that thrive under altered conditions. These non-native species can outcompete native organisms for resources, disrupt ecological interactions, and lead to declines in native biodiversity