Alderssensitive

Alderssensitive is a neologism used in ecology to describe organisms, communities, or ecological processes that respond strongly to the presence or health of alder trees (genus Alnus) in their environment. The term highlights the cascading effects alder stands can have on soil nutrients, moisture regimes, and habitat structure, which in turn influence other species.

Origin and form: The compound combines "alder" with "sensitive" and is sometimes rendered as aldersensitive or alder-sensitive. It is not an official taxonomic term, but a descriptive label used in discussions of species–habitat associations related to alder-dominated ecosystems.

Scope and examples: Alderssensitive responses may be observed in understory plants that benefit from alder-associated nitrogen inputs, aquatic invertebrates that rely on alder leaf litter, and soil or aquatic microbial communities that track alder-derived organic matter. In ecological studies, aldersensitive species are often identified by a stronger correlation with alder cover or by significant abundance differences between plots with and without alders.

Limitations: Because the term is informal, its operational criteria vary between studies. Researchers typically quantify aldersensitive responses using standard landscape metrics, such as alder canopy cover, foliar input rates, and soil nitrogen levels, along with population or community metrics.

See also: Alder, Alnus; Nitrogen fixation; Riparian ecology; Indicator species.