1. Introduction
The emergence of seed plants was a major breakthrough in the evolution
of plant life history (Rutishauser 1993). Seed dispersal, as an
important part of the life history of seed plants, has often been the
focus of attention from and research by biologists. Seed dispersal
depends mainly on movement by wind, water and birds or mammals (Proctor
and V. 1968, Howe 1986, Tackenberg et al. 2003, Kowarik and Sumel 2008).
There are approximately 260,000 kinds of seed plants in the world, and
they all have unique morphological structures to ensure their successful
dispersal. Since 1970, seed dispersal has become one of the research
hotspots in the field of ecology (Butler et al. 2010). Seed dispersal is
not only related to the co-evolution of plants and animals but also
associated closely with environmental issues such as biodiversity
conservation, forest and grassland degradation, habitat fragmentation,
and the invasion of alien species (Byrne and Levey 1993, Campos-Arceiz
and Blake 2011). Therefore, monitoring the international research
progress and academic trends in the field of seed dispersal, tracking
the influence of countries in related research fields and analysing the
characteristics of knowledge evolution in related fields are of great
significance to future research in the field of seed dispersal.
Moreover, understanding the state of research on seed dispersal can
provide scientific guidance for related research.
Although there are many related studies on seed dispersal, there are
still few studies focused on the following issues: (1) Which subject
category is the most popular in the field of seed dispersal? (2) Which
journal most represents research on seed dispersal? (3) Which country
and institution are the most active contributors to seed dispersal
research? What are the differences in research progress between
countries? (4) Which author is most represented in seed dispersal
research? (5) Which articles played a key role in the evolution of
knowledge about seed dispersal? (6) What are the research hotspots in
related fields, and how have they developed and evolved? Addressing
these questions is important for advancing research on seed dispersal;
the answers will provide comprehensive insight into existing seed
dispersal research and help scholars discover important unsolved
scientific problems and determine which problems they should focus their
research on. Although many scholars have published empirical and
qualitative articles in the field of seed dispersal, these scope of
these articles is still somewhat limited, for example, by subject
category or region (Fuzessya et al. 2018, Camargo et al. 2019, Li et al.
2021). Although many reviews have shown development trends in specific
aspects of seed dispersal-related research fields, they have not
provided a comprehensive quantitative analysis of the current status of
seed dispersal-related research and emerging fields. Thus, bibliometric
analysis of seed dispersal research is needed.
Bibliometric analysis, an important quantitative analysis method, can
effectively describe the overall trend of the development of a
discipline or research field and has been widely used to measure the
performance of various research fields (Wang et al. 2018, Liu et al.
2019). Moreover, knowledge graphs can combine information visualization
technology with traditional bibliometric analysis to generate different
types of knowledge graphs through data mining, information processing,
scientific measurement, and graph drawing to provide researchers with
more intuitive data displays (Boyack 2004).
Therefore, we conducted a bibliometric analysis of the scientific
literature on seed dispersal for the period 1985-2020. The main
objectives of this research include (1) determining the basic
characteristics of the literature, such as the number of articles and
citations, categories of research topics and representative journals;
(2) determining the research power in the field of seed dispersal, such
as the countries, institutions and authors represented in the
literature; (3) recognizing the knowledge base of the research field;
(4) discovering the research hotspots and trends of research hotspots
over time; and (5) determining future research opportunities.