Question

Ecologists usually consider native species to have greater "value" than non- native ones. Why do they think this way? Is the rationalization only scientific, or does it include an element of non-objectivity?

Short answer

Ecologists favor native species primarily due to their ecological roles and scientific evidence, but cultural and personal values may add subjective elements.

Step-by-step solution

Understanding Native vs. Non-native Species

Native species are those that naturally occur in a specific ecosystem, while non-native species are introduced, sometimes accidentally or intentionally, by human activity. Ecologists often prioritize native species because they are integral to the local biodiversity and ecosystem function. They have co-evolved with other species, maintaining ecological balance in their native environment.

Ecological Value of Native Species

Native species often provide essential services: they are crucial for maintaining food webs, contributing to soil health, pollination, pest control, and other ecosystem services. They have specific roles that non-native species may not be able to fulfill as effectively.

Impact of Non-native Species

Non-native species may disrupt local ecosystems, sometimes becoming invasive. They can outcompete native species for resources, introduce diseases, or alter habitats. This may lead to reduced biodiversity and destabilization of the ecosystem.

Scientific Rationale

The preference for native species is primarily based on ecology and conservation biology, which are scientific disciplines. These fields emphasize the importance of maintaining ecological integrity and the potential negative impacts of non-native species.

Elements of Non-objectivity

While the scientific rationale is predominant, personal values and cultural connections may influence this perspective. Individuals might value native species for their cultural significance or beauty, which introduces a subjective element to their perceived value.

Key concepts

Non-native Species

Non-native species, often referred to as exotic or alien species, are organisms that have been introduced into an ecosystem where they do not naturally occur. This introduction can happen accidentally, such as through ballast water from ships, or intentionally, like planting foreign crops for agriculture.
While non-native species themselves are not inherently harmful, their presence in a new ecosystem can lead to various ecological changes. Unlike native species, which have evolved over time with other organisms in their environment, non-native species do not share this co-evolutionary history. This lack of shared history can lead to

• competition with native species for resources
• predation on native species that are not adapted to defend against them
• potential habitat alterations
• transmission of new diseases

Understanding the role and impact of non-native species is crucial in maintaining ecosystem balance.

Ecosystem Services

Ecosystem services are the benefits that humans freely gain from the natural environment and properly functioning ecosystems. These services are vital for survival and include a range of processes and resources, such as

• pollination of crops by insects
• purification of air and water
• decomposition of waste
• production of renewable resources like timber and fiber

Native species often play key roles in providing these ecosystem services. For example, native plants might be more efficient in stabilizing soil and preventing erosion, while native pollinators ensure the propagation of local flora.
When non-native species are introduced, the delicate balance required for these services can be disturbed, sometimes leading to irreversible ecological damage.

Biodiversity

Biodiversity refers to the variety and variability of life forms within a given ecosystem, biome, or on the entire Earth. It is a critical measure of an ecosystem's health and resilience.
Rich biodiversity ensures that ecosystems are productive, sustainable, and capable of recovering from various disasters. Native species are key contributors to biodiversity, maintaining intricate relationships through

• food webs
• mutualistic partnerships
• natural population control mechanisms

Non-native species can threaten biodiversity by unsettling these relationships when they become dominant or invasive.
A decrease in biodiversity can compromise the ecosystem's ability to provide essential services and maintain ecological balance.

Invasive Species

Invasive species are a subset of non-native species that cause or have the potential to cause harm to the environment, economy, or human health. They often possess traits such as rapid growth, high reproduction rates, or a lack of natural predators in the new environment.
Invasive species can outcompete native species by monopolizing resources such as food, light, or space. This competition leads to a loss of native biodiversity and can even result in the extinction of some native species. Additionally, invasive species can alter habitat structure, hindering the functioning of the entire ecosystem.
Management strategies to control invasive species include

• physical removal
• the use of biological control methods
• implementing regulations on the trade and movement of potential invasive species

Prevention is often the most cost-effective strategy, emphasizing the importance of monitoring and controlling the introduction of non-native species.