International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.4, 175-186 http://ecoevopublisher.com/index.php/ijmec 1 79 Morales et al., 2013; Russo et al., 2024). In urban and human-transformed landscapes, land use history and habitat connectivity further shape the functional composition and spatial distribution of plant communities by influencing seed propagation (Johnson et al., 2018). 5 The Ecological and Evolutionary Significance of Seed Propagation 5.1 Role in species coexistence and biodiversity maintenance Seed dispersal plays an important role in maintaining species coexistence and diversity in terrestrial ecosystems. Without it, many seeds would die near the mother plant due to density dependence; With it, they can enter new or disturbed environments, reduce competitive pressure, and maintain diversity in their colonies (Beckman and Sullivan, 2023). The form of communication networks is not accidental, but is shaped by the ecological background and evolutionary history. The interaction patterns of different species, the modularity and specificity of the network, all affect the resilience and diversity maintenance of the community (Schleuning et al., 2014). But once the spread is interrupted, such as the disappearance of key animal spreaders or the intervention of invasive species, plant diversity often decreases and community structure changes accordingly (McConkey et al., 2012; Donoso et al., 2022). 5.2 Impact on forest renewal and succession Seed propagation is the core driving force for forest regeneration and ecological succession. Effective propagation can promote the recolonization of disturbed areas, the diffusion of pioneer species and the establishment of late succession species, thereby shaping succession paths and forest structures (Andresen et al., 2018). Animal-mediated transmission, especially the role of primates and birds, has been proven to promote the restoration of degraded habitats and maintain tree species diversity in tropical forests (Andresen et al., 2018). The plasticity of propagation strategies, such as the increase in the propagation rate in the early succession stage, can accelerate species substitution and enhance the resilience of the ecosystem after disturbance. 5.3 The impact of transmission restrictions on cenetic structure and adaptation Restricted transmission, meaning that seeds cannot enter suitable habitats or distant populations, can have a profound impact on genetic structure and adaptive potential. Insufficient dissemination often leads to higher inter population differentiation, weakened gene flow, hindered local adaptation, and even increased extinction risk, especially in fragmented landscapes (Snell et al., 2019; Grasty et al., 2020; Beckman and Sullivan, 2023). At the same time, intraspecific transmission traits are not consistent, and different differences can affect the fitness, population dynamics, and evolutionary direction of plants, as well as their response to environmental changes (Snell et al., 2019). Previous studies have shown that habitat fragmentation can drive rapid evolution of communication strategies, which precisely reflects the dynamic game between ecological conditions and evolutionary processes (Cheptou et al., 2008). 6 Case Study: Seed Propagation in Tropical Rainforests 6.1 The role of neotropical forests and large mammals In the neotropical rainforest, tapirs, primates and rodents such as the brown-haired rat are key seed disseminators, especially for large-seeded tree species. These animals can promote both primary and secondary transmission: primates and birds often transport seeds over long distances after eating fruits, while terrestrial mammals such as the brown-haired rat bury seeds through storage behavior for future use, thus enabling successful germination and establishment of seeds far from the mother plant (Seidler and Plotkin, 2006). The diversity and abundance of disseminators support the high plant diversity and complex community structure unique to tropical rainforests (Figure 1) (Seidler and Plotkin, 2006; Kakishima et al., 2015). 6.2 Loss of communicators and "hollow forest syndrome" Hunting and deanimalization have led to a sharp decline in the number of large vertebrates, resulting in what is known as the "hollow forest syndrome". In Guam and the overhunted Amazon forest, the loss of key disseminators has led to a sharp decline in seedling species richness and increased the spatial aggregation of seedlings, eventually forming plant communities with reduced diversity and greater homogeneity (Wandrag et al., 2017; Culot et al., 2017). Although some small fruit-eating animals can to some extent make up for the loss of
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