Aim Climatic niche breadth (the range of climatic conditions that a species experiences over space and time) is a fundamental topic in ecology, biogeography and evolution. But what determines the climatic niche width of species? In 1967, Janzen suggested that climatic niche widths for temperature were determined by levels of seasonal fluctuation in temperature at each locality, such that niche ...

Understanding dietary specialization in herbivores has theoretical and practical implications in ecology, yet defining niche breadth consistently has been problematic. To increase clarity and communication among ecologists and among disciplines (i.e., chemists, pharmacologists), we propose a specialization key for mammalian herbivores that assigns "obligatory" and "facultative" modifiers to the...

The location of possible glacial refugia of six Apostasioideae representatives is estimated based on ecological niche modeling analysis. The distribution of their suitable niches during the last glacial maximum (LGM) is compared with their current potential and documented geographical ranges. The climatic factors limiting the studied species occurrences are evaluated and the niche overlap betwe...

Background: Theories of density-dependent habitat selection provide two solutions for co-existence of competing species. The niche compression hypothesis predicts that species reduce their respective niche breadths in response to inter-specific competition. Alternatively, if the species have similar resource preferences, the subordinate species may be forced to expand its niche to incorporate s...

Dietary analysis revealed that an impoundment population of Australian bass Macquaria novemaculeata holds a generalist niche, but one arising from persistent individual specialization and interindividual variation. This 'individual specialist' strategy appeared adaptive, but the strength of individual specialization was largely independent of variation in diet composition, except during blooms ...

■ Abstract Niche conservatism is the tendency of species to retain ancestral ecological characteristics. In the recent literature, a debate has emerged as to whether niches are conserved. We suggest that simply testing whether niches are conserved is not by itself particularly helpful or interesting and that a more useful focus is on the patterns that niche conservatism may (or may not) create....

Stem cells remain in specialized niches over the lifespan of the organism in many organs to ensure tissue homeostasis and enable regeneration. How the niche is maintained is not understood, but is probably as important as intrinsic stem cell self-renewal capacity for tissue integrity. We here demonstrate a high degree of phenotypic plasticity of the two main niche cell types, ependymal cells an...

If D = (V,A) is a digraph, its niche hypergraph NH(D) = (V, E) has the edge set E = {e ⊆ V | |e| ≥ 2 ∧ ∃v ∈ V : e = N− D (v) ∨ e = N + D (v)}. Niche hypergraphs generalize the well-known niche graphs (cf. [?]) and are closely related to competition hypergraphs (cf. [?]) as well as double competition hypergraphs (cf. [?]). We present several properties of niche hypergraphs of acyclic digraphs.

This measure ranges between 0 no overlap and 1 complete overlap, so 0. We investigated the niche breadth and overlap of the fish species occurring in four environments affected by the Coaracy Nunes reservoir, in the Amapá.Individual foraging specialization: niche width versus niche overlap. Sargeant sargeantfiu.edu, Dept of Biology, Georgetown Univ.of these insects, and their trophic niche brea...

1. The anatomically simplest GSC niche in C. elegans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. The first structurally and functionally defined GSC niche in the Drosophila ovary . . . . . . . . . . . . . . . . . . . . 4 3. The structurally and mechanistically well-studied GSC niche in the Drosophila testis . . . . . . . . . . . . . . . . . 6 4...