Significance and problems of uneven species distribution for
species coexistence
The formation of micro-landscape heterogeneity is related to patchy and
spatial self-organization in the process of alpine meadow degradation
and succession (Rietkerk et al. 2021). Patchiness is an early warning
sign of ecosystem degradation (Scheffer et al. 2009; Bury et al. 2021)
or the degradation threshold point features of alpine meadow (Song et
al. 2020). After patch development, plant communities begin the process
of spatial self-organization (Rietkerk et al. 2021), which completely
changes the relatively uniform plant landscape to form a unique, stable
and degraded alpine meadow landscape (Van de Koppel et al. 2001).
Therefore, early patchiness is a critical period for grassland
restoration. If patch gaps are occupied by natural reseeding, the
critical degradation threshold points can be avoided to reverse the
degradation of alpine meadows; if this period is missed and community
self-organization is completed in the degraded alpine meadow, the
community structure is difficult to restore.
The community may be jointly influenced by ecological processes at
multiple scales (Levin 1992). The unification of patterns or processes
of ecological communities at local, regional, and global scales is a
focus of recent ecological research (Buckley & Puy 2021; Neves et al.
2021). However, relatively little is known about the effects of the
microscale (i.e., smaller than the local scale). First, it is not
possible to define a ”correct” scale for characterizing broad ecological
phenomena because processes that determine community structure and
dynamics operate at different scales (Levin 1992). Further, although the
local microzone conditions, such as temperature (Klinges et al. 2021),
snow cover, and microtopography (Dobbert et al. 2021), can be quantified
by meteorological data monitoring, and similarly, microscale landscape
patches can be interpreted and quantified by aerial drone photography
(Li et al. 2021), the quantification of community characteristics is
limited by sampling methods. Specifically, the characteristics of
grassland plant communities are traditionally investigated by the
quadrat sampling method, which assumes that the plant species are evenly
distributed within the quadrat; accordingly, the size of the sample
quadrat will affect the discovery of heterogeneity in this
microlandscape, which will be ignored when the quadrat scale is set too
large. Therefore, the study of the size of the quadrat is critical for
determining whether landscape factors play a role, and how to determine
an appropriate quadrat sizes according to plant community types and
ecological processes is a new challenge in community ecology research.
In conclusion, in the degraded alpine meadow the N preferences shifted,
and plant spatial distributions promote N use niche differentiation,
both of which may jointly maintain community stability in degraded
alpine meadows. We emphasize the importance of considering fine-scale
perspectives in studies of niche theory. Our results have an important
implication for restoration of degraded alpine meadows.