Preface to the Special Issue of The Rangeland Journal on the Comprehensive Sequential Classification System of Rangeland

Keywords: CSCSR, rangeland classification system, climate change, rangeland classes, net primary productivity, livestock production, rangeland ecosystem services.

Rangelands are a major ecosystem of the Earth’s biosphere. Responses of given rangeland types to climate change and the implications of policy implementation remain global research topics. We, the authors of this preface, have been engaged in rangeland research all our lives, have visited almost all rangeland types and considered their various classification systems. While we believe that different rangeland classification systems in different countries are certainly appropriate, we also believe that there should be a genetic connection among these systems allowing consistent interpretation similar to that of the uniform biological classification system, where every species in the world can find its place in that system. If such a rangeland classification system was to be considered, then a unified quality assessment of rangeland resources would be possible, even for rangelands in different geographical localities. The Comprehensive Sequential Classification System of Rangeland (CSCSR) we proposed (Ren et al. 2008) is such a global rangeland classification system. We are pleased that the CSCSR has attracted global attention and has undergone further development since its initial definition in the 1950s, especially through its several-times discussion and modification during 1960s–1990s (Fig. 1) and publications in the Rangeland Journal (Volume 36) following a conference jointly held by the IGC (International Grassland Conference) and IRC (International Rangeland Conference) in China in 2008. The CSCSR was further considered at the International Conference on Theory and Application of the Comprehensive and Sequential Classification System of Rangeland and Sustainable Use and Conservation of Global Grassland Resources held at Gansu Agricultural University, Lanzhou, China in September 2019 (the basis for this Special Issue).

Fig. 1.  Discussion about the Comprehensive Sequential Classification System of Rangeland between Professor Ren and Professor Hu (Photo is by Zhengchao Ren).

Ren et al. (2008) described rangeland as ‘a multivariable and multi-functional system’ (p. 199), and defined the basis for their classification. The CSCSR entails a hierarchy of three different classification levels. At the first level, rangelands are grouped into classes according to an index of moisture and temperature. At the second level, rangelands are differentiated as subclasses by edaphic criteria (including landform and soil). At the third level, rangeland types within a subclass are distinguished by vegetation types. Under the CSCSR, seven thermal zones and six humidity zones have been identified and used to differentiate rangeland classes. The CSCSR recognises 42 zonal classes for global rangeland.

The series of papers in this Special Issue deal with this topic, mainly the patterns and magnitudes of global rangeland classes shifting in response to climate change, the application of the CSCSR in conjunction with models to simulate rangeland Net Primary Productivity (NPP), and analysing the response of rangeland NPP to climate change at regional scales. Optimising the interpolation method of the CSCSR classification index further improves the classification accuracy of the CSCSR for terrestrial vegetation. Moreover, since rangelands play an important role in livestock production, the CSCSR-based NPP considered relevant to livestock production is also presented in detail in this Special Issue.

Apart from climate change, human activity is an important factor affecting rangeland ecosystems. Overlaying the CSCSR class map with Land Use and Land Cover Change (LUCC) or NPP data can quantify the extent to which human activities or policy implementation affect rangeland ecosystems. The analysis of rangeland ecological service value must be combined with rangeland classes. In this Special Issue, calculating the value of rangeland ecosystem services based on the CSCSR method is also presented.

We would like to express our thanks to the Australian Rangeland Society for providing this opportunity to publish the CSCSR Special Issue. We believe it will be a useful Special Issue for the Journal’s readers.

Data sharing is not applicable as no new data were generated or analysed during this study.

The authors declare no conflicts of interest.