Aims Ecological strategies related to the adaptation of plants to environmental stress have long been studied by ecologists, but few studies have systematically revealed the ecological process of plant adaptation to herbivores as a whole. Methods In this study, Stipa breviflora, the dominant species in the desert steppe of Inner Mongolia, was used to analyse its reproductive individual characteristics and seed traits as well as the soil seed bank and spatial patterns under heavy-grazing and no-grazing treatments. Important Findings The results showed that the number of reproductive branches positively affected the number of vegetative branches. The analysis of the soil seed bank showed that the density of S. breviflora seeds beneath reproductive S. breviflora individuals was significantly higher than that in bare land. The seed density was also significantly negatively correlated with the seed characteristics and the soil seed bank in bare land. The spatial distribution of S. breviflora was aggregated under heavy grazing. Our results suggest that under heavy grazing, reproductive activity plays a key role in resource allocation. Stipa breviflora evolved the ecological strategy of nearby diffusion by regulating the morphological characteristics of the seeds, which promotes a positive spatial correlation between the juvenile and adult populations at a small scale, thus leading to the formation of “safe islands”.

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An understanding of population adaptation and maintenance mechanisms under interference from large herbivores is lacking and is a major focus of ecological research. In the Eurasian steppe, which has been subjected to continuous interference from domesticated ungulates throughout history and shows increased grazing, it is particularly urgent to analyze the ecological adaptation strategies of widely distributed Stipa plants. In this study, Stipa breviflora in a group of desert steppes in the Mongolian Plateau was selected to study the potential mechanism underlying the maintenance of dominant populations under the continuous interference of heavy grazing from the new perspective of seed germination rate. Laboratory experimental results showed that the values of the phenotypic traits of S. breviflora seeds were lower under a heavy grazing treatment than under a non-grazing treatment, but the seed germination rate did not decrease. The awns of non-grazed seeds significantly affected the seed germination rate, while those of heavily grazed seeds did not. Field observations showed that grazing does not significantly affect the population density of S. breviflora at different growth stages except in extremely wet and dry years. Our study suggests that under heavy grazing, S. breviflora uses an “opportunistic” ecological strategy to ensure population maintenance by increasing the seed germination rate and reducing dispersal via changes in associated seed phenotypic traits.

Allocation is the core concept of life history theory and provides a basis for different strategies (Weiner, 2004). Under environmental stress, plant traits are subjected to strong environmental selection pressure (Harper, 1977), which means that it is difficult for plants to achieve optimal resource allocation. To adapt to stress, under certain resources, an increase in input to one organ will inevitably lead to a decrease in input to another organ. By balancing and adjusting resource allocation, especially between growth and reproduction, life history traits are optimized (Gao, Gao, & XingDong, 2014; Begay, Alexander, & Questad, 2011). The resource allocation between vegetative growth and reproductive growth is flexible (Miller, Tyre, & Louda, 2006). To ensure individual survival, vegetative organs are often maintained at the expense of sexual reproduction because under long-term stress from large herbivores, monocarpic plant species have only one option to respond to grazing. They must repair damage immediately to compensate for biomass losses and damaged reproductive structures (Huhta, Rautio, Hellström, Saari, & Tuomi,

To understand the research trends and areas of focus of seed dispersal, a bibliometric study based on the Science Citation Index Expanded (SCI-E) and Social Science Citation Index (SSCI) databases of the Web of Science Core Collection (WoSCC) was performed. With the help of CiteSpace visualization software, a systematic analysis was carried out on 2911 publications from various countries in the field of seed dispersal. The activity index (AI) and attraction index (AAI) were used to evaluate the research effort and academic impact of different countries/territories in this field, and the global research progress and dynamic changes in research on seed dispersal were discussed. The number of publications on seed dispersal has increased rapidly since 1990, and research on seed dispersal is in the growth stage and has great potential. Ecology was the journal with the highest impact in this field, and ecology was the most popular subject category among the studies analyzed. The most productive authors in the field of seed dispersal are from Spain, and the most productive institution is in the USA. A keyword burst analysis showed that the new research frontiers were mainly concentrated on seed body size and the ecological network of seed dispersal. An in-depth analysis of seed dispersal research indicated that the increasing development of mathematical models related to seed dispersal creates an opportunity to study the processes of seed dispersal and their consequences.