Community Differentiation and Ecological Influencing Factors along Environmental Gradients: Evidence from 1200 km Belt Transect across Inner Mongolia Grassland, China

Round 1

Reviewer 1 Report

Grassland vegetation surveys are quite important for studying grassland biodiversity and assessing the value of grassland ecological services. The work carried out by the authors of this paper in the grasslands of Inner Mongolia is excellent and has yielded relatively valuable data, and the article is good but there are some problems as follows.

1. The language need further edited by the English native speaker.
2. Introduction part of the introduction is not clean enough, only a general introduction, need to review more papers to find the actual data to prove that the current study is not enough.
3. Keywords need to be listed in alphabetical order.
4. Study Area part What is the distribution of meadows and grasslands in Inner Mongolia needs to be supplemented with sampling sites.
5. When the only meteorological factors are precipitation and temperature data, it can‘t be said that these two meteorological factors are the most important，because other meteorological factors were not compared.
6. The abstract states that the grassland influencing factor precipitation is equal to temperature, but it is inconsistent with the results of the RDA analysis.

Author Response

Grassland vegetation surveys are quite important for studying grassland biodiversity and assessing the value of grassland ecological services. The work carried out by the authors of this paper in the grasslands of Inner Mongolia is excellent and has yielded relatively valuable data, and the article is good but there are some problems as follows.

Point 1: The language need further edited by the English native speaker.

Response 1: Revised. Based on your suggestion, we have improved the English language quality of the manuscript by the native English-speaking professionals. The revised version with remarked changes were observed in the whole text.

Point 2: Introduction part of the introduction is not clean enough, only a general introduction, need to review more papers to find the actual data to prove that the current study is not enough.

Response 2: Revised. Based on large-scales research and the distribution of natural grassland, we put forward the novelty as follows in Line 73-83: Grassland plant community research has attracted the attention of many scholars. However, research on the spatial differentiation characteristics of grassland community was relatively less [1-3], and some studies were only focused on small-scales, such as single grassland types, research station, and single region, and the control experiments accounted for a large proportion [4-9]. Additionally, some scholars have proved that there were certain differences and multivariate variation between experimental and real-world communities, and more realistic patterns of community change in natural community should be concerned [10,11]. Therefore, exploring vegetation distribution patterns with a large belt transect in natural grassland across Inner Mongolia grassland at large-scales is necessary, studies on the spatial differentiation characteristics of species composition and structure of natural grassland community, and influencing factors in the Inner Mongolia grassland should be conducted.

References：

1. Ding, X.J.; Su, P.X.; Zhou, Z.J.; Shi, R. Belowground bud bank distribution and aboveground community characteristics along different moisture gradients of alpine meadow in the Zoige plateau, China. Sustainability2019, 11, 2602.
2. Adomou, A.C.; Akoègninou,; Sinsin, B.; Foucault, B.D.; Maesen, L.J.G.V.D. Notulae Florae Beninensis, 13-Biogeographical analysis of the vegetation in Benin. Acta Bot. Gallica2007, 154, 221−233.
3. Wang, Y.H.; Zhao, M.F.; Kang, M.Y. Distribution pattern of main steppe communities in Inner Mongolia region and environmental interpretation. Beijing Norm. Univ., Nat. Sci.2016, 52, 83–90.
4. Chen, B.R.; Zhu, Y.X.; Zhang, H.B.; Zhou, L.; Xin, X.P. Quantitative classification and ordination of meadow grassland vegetations in Hulunber. Wuhan Bot. Res. 2008, 26, 476−481.
5. Chen, B.R.; Li, H.S.; Zhu, Y.X.; Li, G.; Xin, X.P.; Zhang, H.B.; Zhou, L. The spatial pattern and environmental interpretation of the plant community of Hulunber grassland.Acta Ecol. Sin. 2010, 30, 1265−1271.
6. Sha, W.; Dong, S.K.; Liu, S.L.; Liu, Q.R.; Shi, J.B.; Li, X.W.; Su, X.K.; Wu, Y. Spatial patterns of plant community biomass and species diversity in Aerjin Mountain Nature Reserve and their influencing factors. J. Ecol. 2016, 35, 330–337.
7. Fu, Z.Y.; Jiang, H.; Wang, G.Q.; A, Y.L.; Xue, B.L.; Wang, H.Q. Effects of soil properties on plant community structure in a semi−arid grassland. J. Ecol. 2018, 37, 823−830.
8. Wang, Y.T.; Bi, Y.T.; Wang, Q.; Hao, H.C.; Xu, M.H. Spatial differentiation of plant species diversity in subalpine meadows in Shanxi Province. Agri. Sci. Bull.2018, 34, 77–83.
9. Shan, D.; Zhu, Y.J.; Liu, Y.S.; Shi, Z.J.; Yang, X.H.Differentiation of vegetation types and biodiversity in the southern edge of Hulunbuir grassland. J. Ecol. 2019, 38, 619–626.
10. Jochum, M.; Fischer, M.; Isbell, F.; Roscher, C.; Plas, F.V.D.; Boch, S.; Boenisch, G.; Buchmann, N.; Catford, J.A.; Jeannine Cavender-Bares, J.; Ebeling, A.; Eisenhauer, N.; Gleixner, G.; Hölzel1, N.; Kattge, J.; Klaus, V.H.; Kleinebecker, T.; Lange, M.; Provost, G.L.;  Meyer, S.T.; Molina-Venegas, R.; Mommer, L.; Oelmann, Y.; Penone  C.; Prati, D.; Reich, P.B.; Rindisbacher, A.; Schäfer, D.; Scheu, S.; Schmid, B.; Tilman, D.; Tscharntke, T.; Vogel, A.; Wagg, C.; Weigelt, A.; Weisse, W.W.; Wilcke, W.; Manning, P. The results of biodiversity−ecosystem functioning experiments are realistic. Ecol. Evol.2020, 4, 1485−1494.
11. Klaus, V.H.; Whittingham, M.J.; Báldi, A.; Eggers, S.; Francksen, R.M.; Hiron, M.; Lellei-Kovacs, E.; Rhymer, C.M.; Buchmann, N. Do biodiversity−ecosystem functioning experiments inform stakeholders how to simultaneously conserve biodiversity and increase ecosystem service provisioning in grasslands? Conserv.2020, 245, 108552.

Point 3: Keywords need to be listed in alphabetical order.

Response 3: Revised. We revised keywords in alphabetical order in Line 45 as follows, community differentiation, Inner Mongolia grassland, meadow steppe, typical steppe.

Point 4: Study Area part What is the distribution of meadows and grasslands in Inner Mongolia needs to be supplemented with sampling sites.

Response 4: Revised. We supplemented the distribution regions of meadow and typical grasslands in Line 116-119 as follows: 21 sites in typical steppe (S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S19, S20, S21, S22, S23, S24, S34, S35, S36) and 15 sites (S1, S2, S3, S16, S17, S18, S25, S26, S27, S28, S29, S30, S31, S32, S33) in meadow steppe, which included most of the dominant species and main vegetation types.

Point 5: When the only meteorological factors are precipitation and temperature data, it can‘t be said that these two meteorological factors are the most important, because other meteorological factors were not compared.

Response 5: In this study, study region stretches from 41.70˚N to 50.36˚N in latitude and from 111.77˚E to 121.06˚E in longitude, and formed a 1,200 km belt transect across Inner Mongolia grassland, which belonging to large-scales research. The climate of the region is temperate continental monsoon climate, the precipitation is decreasing from east to west, and the temperature is also decreasing from south to north, indicating that precipitation and temperature played an important role in vegetation distribution in large scales, Siefert et al, and Chinese Academy of Sciences also proved this point [12,13]. Therefore, we chose the precipitation and temperature as the most important factors to analyze the ecological influencing factors. Additionally, other meteorological factors which may influence community structure are not mentioned, so we also focus on the effect of more meteorological factors on community characteristics in the future research, this point has been supplemented in Discussion in Line 408-412.

References：

12. Siefert, A.; Ravenscroft, C.; Althoff, D.; Alvarez−Yépiz, J.C.; Carter, B.E.; Glennon, K.L.; Heberling, J.M.; Jo, I.S.; Pontes, A.; Sauer, A.; Willis, A.; Fridley, J.D. Scale dependence of vegetation−environment relationships: a meta−analysis of multivariate data. Veg. Sci. 2012, 23, 942–951.
13. Chinese Academy of Sciences. Vegetation Atlas of China. Science Press, Beijing, 2001.

Point 6: The abstract states that the grassland influencing factor precipitation is equal to temperature, but it is inconsistent with the results of the RDA analysis.

Response 6: Revised. Thank you for your advice, the sentence of “Redundancy analysis (RDA) revealed that the spatial differentiation characteristics along longitude gradients were chiefly driven by precipitation” was the improper expression, and we didn’t add restricted conditions ‘in typical steppe’, the right one as follows in Line 34-36: Redundancy analysis (RDA) revealed that the spatial differentiation characteristics in typical steppe were chiefly driven by precipitation, while the influencing factor in meadow steppe was soil nutrients, followed by temperature and precipitation.

Reviewer 2 Report

Dear authors,

I find that your manuscript brings a significant contribution to the methodological approach to analyzing the status of plant communities. I particularly like the section dedicated to factors influencing the characteristics of plant communities in the Inner Mongolia Grassland, which could provide additional comparative references for studies focusing on grassland degradation. I would like to suggest you expand the section on sampling design, by introducing some additional points on the practical issues of plot sampling size, number, and distribution, mainly how did you reach an adequate sampling. Also, the discussion part could include some insight on the strong points and shortcomings of your method, that could be addressed in future research.

Author Response

Comments：I find that your manuscript brings a significant contribution to the methodological approach to analyzing the status of plant communities. I particularly like the section dedicated to factors influencing the characteristics of plant communities in the Inner Mongolia Grassland, which could provide additional comparative references for studies focusing on grassland degradation. I would like to suggest you expand the section on sampling design, by introducing some additional points on the practical issues of plot sampling size, number, and distribution, mainly how did you reach an adequate sampling. Also, the discussion part could include some insight on the strong points and shortcomings of your method, that could be addressed in future research.

Response: Thank you for your advice, we supplemented the plot sampling size, total sampling number and other additional information in Line 120-129 as follows: At each of the 36 sites, a place of 10 m ´10 m which was homogeneous in terms of vegetation structure was identified, and three representative quadrats with 1 m² within the 10 m´10 m were randomly selected for plant and soil sampling by avoiding the low−lying, steep slopes, and residential area, and a total of 108 quadrats were obtained. Each quadrat was investigated for species composition, numbers, height, cover of all vascular plants, and all plants in 1 m² quadrat were harvested to measure above-ground biomass. Based on the previous studies and ‘Vegetation Atlas of China’, the distribution regions of dominant species in meadow and typical steppes were obtained, ensure the effective and representative sampling including all the dominant species in typical and meadow steppes, so as to ensure the adequate samples, and achieve reliable results. Finally, we chose 108 quadrats within 36 plots and formed a 1,200 km belt transect across Inner Mongolia grassland at large-scale. In Discussion Part, we supplemented and reiterated the novelty and shortcomings of this study, and moderately forecast the future research in Line 366-369, 408-412, 431-433. Additionally, we only chose the precipitation and temperature data as the meteorological factors to explore the community differentiation, but other meteorological factors which may influence community structure were not mentioned in this study, so we also pay attention to the effect of more meteorological factors on community characteristic and functions in future research.