Global environmental change and sustainable development have been among the most critical scientific issues and challenges of the 21st century. Accumulating multi-element, multi-scale, and multi-process ecological data through ecosystem observation serves as an essential foundation for achieving sustainable development. Transect-based ecosystem studies have been recognized as one of the most effective approaches to addressing these challenges. Recently, a research team from Northeast Forestry University (NEFU) proposed the concept of the North–South Transect of Eastern Asia (NSTEA) and carried out a systematic investigation, completing the construction and preliminary survey of the transect stretching from tropical rainforests to Arctic tundra at the northern edge of the Eurasian continent.

Terrestrial transect research has a history of several decades in global ecology. At the end of the 20th century, the International Geosphere–Biosphere Program (IGBP) proposed establishing Global Terrestrial Transects (GTTs) as standardized platforms for investigating ecosystem changes along environmental gradients. Subsequently, transects were established in North America, the Amazon, and Africa to systematically monitor key ecological indicators such as vegetation, biodiversity, carbon cycling, and soil processes. These transects provided valuable data for understanding spatial ecological patterns driven by variations in climate, soil, and topography, and promoted the development of global change ecology and sustainable ecosystem assessment.

China began participating in related research in the 1990s and has since established two standard transects: the North–South Transect of Eastern China (NSTEC), jointly initiated by Prof. Zhou Xiaofeng of NEFU and Prof. Peng Shaolin of Sun Yat-sen University, and the Northeast China Transect (NECT), undertaken by Academician Zhang Xinshi of the Institute of Botany (CAS). From 2013 to 2018, Prof. He Nianpeng’s team, supported by Academician Yu Guirui, conducted community structure surveys and collected coordinated plant–soil samples across nearly 20 forest ecosystems along the NSTEC, from Huzhong (cold-temperate coniferous forest) to Jianfengling (tropical monsoon forest). They measured 112 functional traits for more than 4,000 plant species, systematically revealing the large-scale variation characteristics and regulatory mechanisms of forest ecosystems.

Photo 1: The 15 Standard Transects of the International Geosphere-Biosphere Program (IGBP)

Although existing transects have provided essential insights into global changes in temperature, precipitation, and land use, several limitations remain. First, their fragmented spatial and climatic coverage restricted their ability to reveal complete environmental gradient patterns. Second, monitoring indicators often focus on species composition or biomass, lacking multidimensional measurements of functional traits, soil processes, and ecosystem services. Third, interdisciplinary and transnational data integration was limited by inconsistent standards and monitoring systems, hindering the development of globally comparable datasets. Therefore, there was an urgent need to establish a large-scale transect that reached from the tropics to the polar regions, enabling comprehensive assessments of ecosystem responses to global change and supporting large-scale sustainable development.

To address these challenges, under the guidance of Academician Yu Guirui, Professor He Nianpeng and his team proposed the concept of the North–South Transect of Eastern Asia (NSTEA) and took the lead in conducting a systematic field investigation. The NSTEA extended approximately 7,000 km, covering all major climatic zones and representative ecosystem types—from tropical rainforests and subtropical evergreen broad-leaved forests to temperate deciduous and mixed forests, boreal coniferous forests, and Arctic tundra. The transect exhibited a typical biodiversity gradient and represented one of the world’s most important carbon sink systems, endowing it with global uniqueness in completeness and representativeness.

Previously, Academician Yu Guirui and Prof. He Nianpeng’s team had conducted extensive research in the southern section of the NSTEA, while linking the northern section remained a critical challenge. To extend the transect northward, during the summers of 2024 and 2025, Prof. He’s team collaborated internationally with the Melnikov Permafrost Institute and the Institute for Biological Problems of the Cryolithozone under the Siberian Branch of the Russian Academy of Sciences, establishing principles for transect construction and key survey site selection. From July to August 2025, field teams led by Dr. Zhang Jiahui and Dr. Zong Xin from Prof. He’s group, Dr. Wang Jing from Prof. Zhou Xuhui’s team, and Dr. Jin Xiaoying and Dr. Zhang Shengrui from Prof. Jin Huijun’s team, completed the construction and preliminary survey of the NSTEA’s northern section, from Mohe, China, to the Arctic tundra near the Arctic Ocean.

During one 40-day stretch of continuous fieldwork, the researchers established ten new sampling plots within Russian territory and conducted community structure surveys, plant–soil sample collection, and key functional trait measurements. Looking ahead, the team planned to extend the transect further southward through collaboration with universities in Thailand, expanding the transect’s coverage toward equatorial regions. Future research will integrate field survey data with flux observations, LiDAR, and satellite remote sensing to achieve the integration of ground observations, remote sensing data, and model simulation, thereby constructing a comprehensive 3D monitoring database for the NSTEA to support long-term ecological monitoring and mechanism-based research.

Photo 2: The Setup and Preliminary Survey of the North-South Transect of Eastern Asia (NSTEA)

The North–South Transect of Eastern Asia (NSTEA) serves as an ideal interdisciplinary research platform integrating ecology, earth sciences, and biology. It enables multi-dimensional research, including systematic assessment of carbon sequestration capacity and carbon cycle characteristics across different climatic zones, analysis of biodiversity’s role in maintaining ecosystem stability and productivity, and large-scale real-time monitoring and prediction of vegetation dynamics through remote sensing and artificial intelligence technologies.

The preliminary establishment and systematic investigation of the NSTEA marks a new stage in ecosystem ecology research, transitioning from regional transects to full climatic gradient coverage across the Northern Hemisphere. This milestone provides a solid data foundation for understanding ecosystem responses to global change and evaluating ecosystem services. In the future, the NSTEA will offer critical support for basic scientific research, interdisciplinary ecological monitoring, long-term forest management, and global ecosystem assessment, contributing to the comprehensive evaluation of sustainable development goals.

Photo 3: Group Photo of the North-South Transect of Eastern Asia (NSTEA) Survey Team