Fig 4. Correlations between plant functional groups and micro-topography
and climate
Note: A, F, and
K
represent the biomass, coverage, and importance value of Gramineae,
respectively; B, G, and L
represent
the biomass, coverage, and importance value of Cyperaceae, respectively;
C, H, and
M
represent the biomass, coverage, and importance value of Leguminosae,
respectively; D, I, and N
represent
the biomass, coverage, and importance value of forbs, respectively; E,
J, and O represent the biomass, coverage, and importance values of
shrubs, respectively; and P, Q, R, S, and T represent
the
accumulated temperature above 0°C, the accumulation of precipitation,
and latitude, longitude, and altitude, respectively.
2.3
Relationships between micro-topographic factors and steady stages
The characteristics of mini-patches investigated in our research show
that 11.1% could be classified to
Gramineae–K.
humilis and Gramineae–K. humilis to K. pygmaeatransitional mini-patches, 16.3% could be classified to healthy and
thickening mattic epipedon in K. pygmaea meadow, 36.2% could be
classified to cracking mattic epipedon in K. pygmaea meadow,
16.6% could be classified to eroded mattic epipedon in K.
pygmaea meadow, and 19.8% could be classified to black-soil beach
meadow (Table 2).
Most of the mini-patches were located on sunny or semi-sunny slopes with
angles of less than 10° or in valleys between hills. Livestock grazing
intensities affected mini-patches differently and the K. pygmaeamini-patches were more degraded if they were located in the middle of
slopes than if they were located elsewhere. Herders typically use
pastures located lower on slopes or in valleys as reserve forage
production areas because their superior climate conditions facilitate
the growth of forage for use in cases of natural disasters or other
emergencies. Therefore, more than 90 % of the
Gramineae
and Gramineae–K. humilis mini-patches occurred in such areas
(Table 2).
Our findings indicate that as grazing intensity increased, total plant
community coverage decreased. In addition, the total plant community
coverage in eroded mattic epipedon K. pygmaea meadows and
black-soil beach meadows were not significantly different but were lower
than that in other types of meadow. In addition, our findings confirm
the generally accepted belief that healthy alpine meadows invariably
maintain a certain thickness of mattic epipedon (typically 4-5 cm)
(Table 2).
Table 2. Micromorphology in alpine meadows under different grazing
intensities