Final answer:
A physiological filter in invasion biology refers to the challenges that exotic species must overcome to invade a new ecosystem, such as environmental conditions and competition with native species. These filters significantly impact the success of exotic species invasions, especially in ecosystems that have been disrupted or are experiencing variability and severity in environmental conditions.
Step-by-step explanation:
A physiological filter is a concept in invasion biology that refers to the environmental and biotic barriers that an exotic or alien species must overcome in order to successfully invade a new ecosystem. These filters include a variety of factors, such as compatibility with the new environment's climate, availability of resources, absence of natural predators, and the ability to compete with native species.
To pass through this filter, invasive species often possess traits that allow them to adapt, survive, or reproduce under the conditions of the new ecosystem. Successful invasions are more likely when native ecosystems are already depleted or disrupted, which can lower the resistance posed by the physiological filter. Aquatic systems, for instance, can be particularly vulnerable due to interactions among environmental variability, predictability, and severity.
Invasibility of ecosystems by exotic species can have significant ecological consequences, including disruption of native food webs, out-competition of native species, introduction of diseases, and economic impacts. The role of physiological filters is critical in understanding the patterns and processes that underlie biological invasions and their effects on biodiversity.