International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.4, 175-186 http://ecoevopublisher.com/index.php/ijmec 1 81 suitable habitats, and the coverage of seed rain will subsequently shrink (Borah and Beckman, 2024; Fonturbel et al., 2015). Due to the lack of sufficient redundancy in the dissemination function, once key species disappear, it is often difficult to be replaced by other species. As a result, there are chain changes in both plant renewal and community structure (Leal et al., 2013; Perez-Mendez et al., 2016; Da Silva et al., 2024). 7.2 Climate change The impact of climate change is more reflected in temporal and spatial patterns. With the changes in temperature and precipitation patterns, the original synchronicity between the fruiting period of plants and animal activities was disrupted, and thus the success rate of seed propagation decreased (Teixido et al., 2022; Hernandez et al., 2023). Frequent droughts and extreme weather further reduce the number and activity range of disseminators. For example, ants significantly decrease under such conditions, and the speed and distance of seed dissemination also decrease accordingly, especially in areas where the ecosystem is already fragile (Oliveira et al., 2019; Hernandez et al., 2023). These changes not only threaten the ability of plants to migrate along with climate niches, but also weaken genetic connectivity (Hernandez et al., 2023). 7.3 Invasive species Once invasive species enter, the original seed propagation network is often disrupted. Invasive plants not only compete with native plants but may also directly vie for resources of disseminators. Invasive animals, on the other hand, can alter the efficiency and composition of spreaders (Teixido et al., 2022; Da Silva et al., 2024). This influence is even more pronounced in an environment where human intervention is intense. Whether in urban areas or large-scale plantations, communication networks tend to be single, randomness increases, and the diversity and number of native communicators decline significantly (Da Silva et al., 2024). Furthermore, humans themselves often unintentionally promote the spread. Road and vehicle transportation became the medium of diffusion, enabling invasive plants and even genetically modified crops to expand rapidly in a short period of time (Garnier et al., 2008; Beckman et al., 2019; Johnson et al., 2020). 8 Methodological Approaches to Seed Propagation Research 8.1 Field observation and seed tracking methods Direct field observations, including seed collectors, population censuses, and tracking of labeled seeds, remain fundamental methods for quantifying propagation distance and sedimentary patterns. These methods are crucial for capturing the propagation process at the local scale and verifying the model, but they are often limited by logistical challenges and operational difficulties when tracking long-distance propagation or propagation in complex environments (Schupp et al., 2010; Beckman et al., 2019; Kim et al., 2022). Experimental studies, such as feeding experiments in animal-mediated transmission (e.g., fish transmission), can quantify different stages of transmission and reveal the influence of plant and vector traits (Pollux, 2011). Combining phytocentric and zoocentric sampling methods contributes to a more comprehensive understanding of propagation networks and their interactions (Lussier et al., 2024). 8.2 Genetic markers and parent-child analysis Genetic techniques, such as molecular markers and parent-child analysis, have revolutionized researchers' ability to correlate scattered seeds or seedlings with their mother plants, making accurate measurements of long-distance transmission possible, which were often difficult to achieve in traditional methods (Cain et al., 2000; Wang and Smith, 2002; Jones and Muller-Landau, 2008). These methods can be combined with classical methods to improve the propagation distribution estimation at the population level, but sampling bias and interference from external germline sources need to be fully considered (Cain et al., 2000; Jones and Muller-Landau, 2008). The advancement of genetic attribution and likelihood analysis methods has continuously expanded the scope and resolution of seed propagation research (Cain et al., 2000; Wang and Smith, 2002). 8.3 Propagation core modeling and landscape connectivity analysis Mathematical and simulation models, including mechanism models and statistical propagation kernels, have been widely used to describe and predict seed propagation patterns across landscapes (Russo et al., 2006; Cousens et al., 2010; Bullock et al., 2017; Kim et al., 2022). Propagation nuclei, as the probability distribution of seed movement,
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