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![Hypothetical community assembly processes under the scenarios of selective and random extinction, and the predicted patterns within the framework of the Theory of Island Biogeography by integrating species traits and phylogenies. (a) Local environmental condition eliminates vulnerable species, resulting in bird communities more clustered on smaller and remoter islands. (b) Competition eliminates ecologically similar species, leading to higher degree of overdispersion on smaller islands; facilitation might increase the probability of colonisation, resulting in communities on remoter islands more overdispesed. (c) Random extinction assumes species have an equal probability of extinction disregarding species identity and island properties, leading to random functional and phylogenetic patterns. The circles represent species, and red indicates species with a higher vulnerability to environmental stress than the green ones. SES.MFPD is the standardised effect size of the mean functional-phylogenetic distance. Shaded regions indicate the corresponding ranges of expected SES.MFPD of bird communities on the mainland. See more details for SES.MFPD in Materials and methods. [Colour figure can be viewed at wileyonlinelibrary.com]](profile/Xingfeng-Si/publication/313294887/figure/fig4/AS:667897294774275@1536250532114/Hypothetical-community-assembly-processes-under-the-scenarios-of-selective-and-random.png)
Hypothetical community assembly processes under the scenarios of selective and random extinction, and the predicted patterns within the framework of the Theory of Island Biogeography by integrating species traits and phylogenies. (a) Local environmental condition eliminates vulnerable species, resulting in bird communities more clustered on smaller and remoter islands. (b) Competition eliminates ecologically similar species, leading to higher degree of overdispersion on smaller islands; facilitation might increase the probability of colonisation, resulting in communities on remoter islands more overdispesed. (c) Random extinction assumes species have an equal probability of extinction disregarding species identity and island properties, leading to random functional and phylogenetic patterns. The circles represent species, and red indicates species with a higher vulnerability to environmental stress than the green ones. SES.MFPD is the standardised effect size of the mean functional-phylogenetic distance. Shaded regions indicate the corresponding ranges of expected SES.MFPD of bird communities on the mainland. See more details for SES.MFPD in Materials and methods. [Colour figure can be viewed at wileyonlinelibrary.com]
Source publication
1. Biodiversity change in anthropogenically transformed habitats is often nonrandom, yet the nature and importance of the different mechanisms shaping community structure are unclear. Here, we extend the classic Theory of Island Biogeography (TIB) to account for nonrandom processes by incorporating species traits and phylogenetic relationships into...
Contexts in source publication
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... are two opposing scenarios of community assem- bly that might explain local extinctions following habitat loss and fragmentation: selective (or nonrandom) and ran- dom extinction (Arroyo-Rodr ıguez et al. 2012;Terzopoulou et al. 2015;Si et al. 2016) (Fig. 1). Selective extinction depends on various nonrandom processes, such as environmental filtering and competitive exclusion that creates distinct community patterns that are different from that expected under random assembly (MacArthur & Levins 1967;Purvis et al. 2000;Chase & Leibold 2003;G€ otzenberger et al. 2012). In addition, these ...
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... isolated fragments should appear function- ally and phylogenetically clustered, while communities on the mainland, which lack dispersal limitation and provide more environmental opportunities should tend towards being representative of the regional species or overdis- persed if competition is important or if there is high habi- tat heterogeneity (Fig. ...
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... and are more likely to be competitively excluded because of the limited resources (G omez et al. 2010;Sobral & Cianciaruso 2016), or priority effects that inhibit the colonisation of closed related species (Fukami 2015;Klingbeil & Willig 2016), leading to higher degrees of functional and phylo- genetic overdispersion on fragment islands (Fig. 1b). Fur- thermore, we could also expect that isolated communities are overdispersed relative to the mainland if, for example, facilitation increases the probability of colonisation, although this may not be likely if dispersal ability is the limiting ...
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... competition can also eliminate more different and less related species, and can result in community clustering (Mayfield & Levine 2010). Thus, bird communities on small islands may be more ecologi- cally clustered than on large islands because of increased competition, and we can expect similar patterns as the scenario of environmental filtering (Fig. 1a). In reality, abiotic and biotic mechanisms are not easily separable, but by linking patterns of habitat heterogeneity and domi- nant species traits to island area and isolation, we can better understand the mechanisms driving community assembly on fragment ...
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... 2014), we can use TIB as a null model for changes in functional or phylogenetic patterns with fragmentation. Thus, the null expectation is that there should be no difference in the com- munity patterns from mainland and island observations since all species have an equal probability of extinction regardless of species traits and island properties (Fig. ...
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... bird communi- ties across 36 islands that differ in area and isolation. The goal of this study is to place functional-phylogenetic anal- yses of community structure of island birds within the framework of TIB, with the broader goal of potentially extending TIB to examining community assembly by accounting for species' ecological nonequivalence (Fig. 1) insights into TIB? Specifically, (ii) are the bird communi- ties clustered or overdispersed on study islands? And (iii) do bird community structures vary with island area and ...
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... island birds from this study. We then sampled 5000 pseudo-posterior distributions and constructed the Maximum Clade Credibility tree using mean node heights by the software TreeAnnonator v1.8.2 of the BEAST package (Drummond & Rambaut 2007;Ricklefs & Jønsson 2014). We used this resulting tree for all subsequent analyses on phylogenetic analyses (Fig. S1). Similar to the procedures for island birds' tree, we also constructed the phylogenetic tree of 55 mainland birds for further analyses (Fig. ...
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... is the mean of the simulated values from 999 randomised communities, and SD null is the standardised deviation of the simulated values. SES.MFPD could thus be interpreted in terms of community assembly patterns: the negative values of SES.MFPD indicate community clustering, and positive values indicate community overdispersion ( Webb et al. 2002; Fig. ...
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... both biotic and abiotic processes can produce cluster- ing (i.e. Fig. 1a), we additionally analysed habitat heterogeneity and variance in size ratios (VSR) as an attempt to detect poten- tial drivers. First of all, we defined habitat richness as the number of habitat types on each island (Table S2). Because habitat rich- ness significantly increased with island area in this study (R 2 = 0Á84, P < 0Á001; Fig. ...
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... analyses of VSR of body mass showed that observed values were not significantly lower than sampled values from null communities, neither for all species (Fig. S6) nor each guild (Fig. S7) on each island. Instead, the observed VSR on two islands (Islands 17 and 35) for all species, as well as the observed VSR on Island 17 for omni- vores were significantly higher than sampled VSR (Figs S6 and S7b). ...
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... sites. Table S2. Habitat types on study islands. Table S3. Occupancy data of breeding birds on islands and the mainland. Table S4. Trait data of breeding birds on islands and the mainland. S5. Relationships between SES.MFPD and island variables for each guild. . Relationships between mean functional-phylogenetic dis- tance and island variables. Fig. S10. Bird diversity and community structure that incorporate species ...
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... While the ETIB primarily focuses on species richness, phylogenetic diversity considers the evolutionary history, ecological functions, and species combinations within island plant communities [9][10][11]. From an evolutionary perspective, the importance of biodiversity conservation varies among species within communities, where the current pattern of biodiversity distribution is an outcome of a series of evolutionary processes [12]. In scenarios with limited resources, priority should be accorded to protecting groups that are evolutionarily distinct from other species [12]. ...
... From an evolutionary perspective, the importance of biodiversity conservation varies among species within communities, where the current pattern of biodiversity distribution is an outcome of a series of evolutionary processes [12]. In scenarios with limited resources, priority should be accorded to protecting groups that are evolutionarily distinct from other species [12]. Community phylogeny, which includes phylogenetic relationships and evolutionary data among species, forms a crucial aspect of biodiversity [13]. ...
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... For example, species like Phoenicurus leucocephalus, Culicicapa ceylonensis, and Tachybaptus ruficollis, despite belonging to different families and being distributed in different patches, manifest comparable functional traits such as trophic level, territoriality, and flocking tendency. Further studies using null models to quantify the functional structure of bird communities can provide insights into the extent of true functional redundancy (Si, Cadotte, et al., 2017;Sinha et al., 2022). ...
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... However, escalating human activities are causing severe biodiversity crises [1,2], with land use change being a primary driver of global biodiversity loss [3]. This change involves altering the physical environment and vegetation structure at the habitat level [3,4], leading to unpredictable fluctuations in biodiversity [4] and continuous changes in biological structure and ecological community composition [1], with implications for different dimensions of biodiversity, such as taxonomic diversity, functional diversity, and phylogenetic diversity. ...
... However, escalating human activities are causing severe biodiversity crises [1,2], with land use change being a primary driver of global biodiversity loss [3]. This change involves altering the physical environment and vegetation structure at the habitat level [3,4], leading to unpredictable fluctuations in biodiversity [4] and continuous changes in biological structure and ecological community composition [1], with implications for different dimensions of biodiversity, such as taxonomic diversity, functional diversity, and phylogenetic diversity. ...
... Subsequently, the phylogenetic tree was obtained from the "Hackett All Species: a set of 10,000 trees with 9993 OTUS each" database, including 5000 pseudo-posterior distributions. Finally, the Maximum Clade Credibility tree was constructed using the average node height by TreeAnnonator software (v 1.10.4) of the BEAST package [4]. The resulting phylogenetic tree served as the basis for all subsequent phylogenetic correlation analyses in this study. ...
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... The results of functional β rich also suggest that functional diversity correlates with island size. This is consistent with previous studies about the relationship between functional diversity and island size (Jacquet et al., 2017;Si et al., 2017;Whittaker et al., 2014). This result was considered to be influenced by both variance of species richness (Swenson, 2014) and pure variation of island size (Jacquet et al., 2017;Ross et al., 2019). ...
This study investigated the relative influences of environmental, spatial, and historical factors, including the island‐specific history of land connectivity, on bat assemblages in the Japanese Archipelago. We collected bat distribution data from 1408 studies and assigned them to Japan's First Standard Grid (approximately 6400 km ² ). Japanese bat assemblages were analyzed at two scales: the entire Japanese Archipelago comprised 16 islands and exclusively the four main islands. At first, we calculated taxonomic and functional total beta diversity ( β total ) by Jaccard pairwise dissimilarity and then divided this into turnover ( β repl ) and richness‐difference ( β rich ) components. We conducted hierarchical clustering of taxonomic beta diversity to examine the influence of the two representative sea straits, Tsugaru and Tokara, which are considered biogeographical borders. Variation partitioning was conducted to evaluate the relative effects of the three factors on the beta diversity. Clustering revealed that the Tokara Strait bordered the two major clades; however, the Tsugaru Strait did not act as a biogeographical border for bats. In the variation partitioning, shared fraction between spatial and historical factors significantly explained taxonomic and functional β total and taxonomic β repl at the entire archipelago scale, but not at the four main islands scale extending only Tsugaru Strait but not Tokara Strait. Pure environmental factors significantly explained functional β total at both scales and taxonomic β total only at the four main islands scale. These results suggest that spatial and historical factors are more pronounced in biogeographical borders, primarily structuring assemblage composition at the entire archipelago scale, especially in taxonomic dimension. However, current environmental factors primarily shape the assemblage composition of Japanese bats at the main island scale. The difference in results between the two scales highlights that the primary processes governing assemblages of both dimensions depend on the quality of the dispersal barriers between terrestrial and aquatic barriers for bats.
... Studies on the growth habits of Rhododendrons seem to confirm that this theory also applies to mountains regions (Gibbs et al., 2011), as mountains with large areas provide sufficient habitats. Furthermore, mountains with smaller areas have lower species diversity (Si et al., 2017), most likely due to increased competition between species. This relationship between island area and species diversity has been shown to exist in other terrestrial habitat islands, such as grassland patches in the agro-pastoral ecotone (Zhang et al., 2021), forest islands (Lovei et al., 2006), alpine plants (Sklen a r et al., 2014). ...
... functional and/or phylogenetic overdispersion) [25,26] through competitive exclusion of closely related species. However, empirical studies of various taxa have found that the structure of island assemblages is, in general, phylogenetically and functionally clustered [26,30,31]. Given the presence of severe environmental filters and limited habitat diversity on small We predict an interactive affect between land-use types and island attributes (i.e. ...
... Additionally, extended analysis showed that remote islands possess bird species with higher average dispersal abilities (measured by the hand-wing index; see electronic supplementary material, text S6 and figure S9b for more details). Taken together, these results indicate that a 'landscape of fear' and/or limited dispersal ability may restrict the distribution of some species during the breeding season in our study system [30]. ...
Anthropogenic activities have reshaped biodiversity on islands worldwide. However, it remains unclear how island attributes and land-use change interactively shape multiple facets of island biodiversity through community assembly processes. To answer this, we conducted bird surveys in various land-use types (mainly forest and farmland) using transects on 34 oceanic land-bridge islands in the largest archipelago of China. We found that bird species richness increased with island area and decreased with isolation, regardless of the intensity of land-use change. However, forest-dominated habitats exhibited lower richness than farmland-dominated habitats. Island bird assemblages generally comprised species that share more similar traits or evolutionary histories (i.e. functional and/or phylogenetic clustering) than expected if assemblages were randomly assembled. Contrary to our expectations, we observed that bird assemblages in forest-dominated habitats were more clustered on large and close islands, whereas assemblages in farmland-dominated habitats were more clustered on small islands. These contrasting results indicate that land-use change interacts with island biogeography to alter the community assembly of birds on inhabited islands. Our findings emphasize the importance of incorporating human-modified habi- tats when examining the community assembly of island biota, and further suggest that agricultural landscapes on large islands may play essential roles in protecting countryside island biodiversity.
... However, a random pattern rather than functional clustering was observed, indicating that stochasticity and ecological drift are the primary processes regulating fish trait composition. The effects of stochastic processes on community structure have been found in previous studies on macroinvertebrates and diatoms in the Chishui River basin , fishes, macroinvertebrates, and macrophytes in the Yangtze River (Jia et al., 2021;Liu & Wang, 2018) and other taxa in terrestrial landscapes (Cadotte et al., 2019;Si et al., 2017). We, therefore, upheld the idea that deterministic processes and stochasticity work together in governing fish community assembly, which only partially supported our second hypothesis (H2). ...
Aim
Understanding the patterns and drivers of biodiversity across space and time is commonly based on species diversity, which may ignore species' functional role and evolutionary history and result in an incomplete understanding of community assembly. It is suggested that integrating species, functional, and phylogenetic diversity could provide a more holistic assessment of community assembly in natural ecosystems. This study aimed to explore the elevational patterns and environmental drivers of multiple facets of fish diversity and community structure in a subtropical river during the wet and dry seasons.
Location
The Chishui River basin, China.
Methods
We investigated the responses of fish species richness, functional richness, and phylogenetic diversity to elevation in different seasons. Moreover, we compared functional dispersion and mean pairwise distance with those obtained from null models to infer assembly mechanisms shaping community structure. Additionally, we examined the environmental drivers (e.g. water chemistry, temperature, and river size) of fish diversity and community structure.
Results
Fish species richness, functional richness, and phylogenetic diversity showed a negative relationship with elevation in the Chishui River basin. Fish communities tended to be on average functionally random but phylogenetically clustered. Furthermore, phylogenetic structure exhibited a decreasing pattern along the elevational gradient. Despite no significant seasonal changes for fish diversity (except for phylogenetic diversity), fish communities became more phylogenetically overdispersed and clustered at low and high elevations in the dry season. Additionally, the responses of fish diversity and community structure to environmental variables were not synchronous.
Conclusions
At the basin scale, environmental filtering was prevalent in shaping fish phylogenetic structure, whereas stochasticity was likely more important for functional structure. Moreover, the ecological mechanisms shaping individual fish communities switched from limiting similarity to environmental filtering as elevation increased, and the underlying forces at two ends of the elevational gradient became more prominent in the dry season.
... It may be a more general pattern that invasive plants are more favored on fragments (such as habitat islands in our study) where local communities have a diverse assemblage of generalized mutualists dispersing their seeds (Emer et al., 2020;Renne et al., 2002). In general, community structure may be simplified after habitat fragmentation events (Si et al., 2017), leading to mostly diet-generalized and resistant species persisting on these habitat islands (Boyer & Jetz, 2014). In addition, remnant species may become more common and expand their trophic niches on islands Olesen et al., 2002;Traveset et al., 2015). ...
Seed dispersal by frugivorous birds facilitates plant invasions, but it is poorly known how invasive plants integrate into native communities in fragmented landscapes. We surveyed plant–frugivore interactions, including an invasive plant (Phytolacca americana), on 22 artificial land‐bridge islands (fragmented forests) in the Thousand Island Lake, China. Focusing on frugivory interactions that may lead to seed dispersal, we built ecological networks of studied islands both at the local island (community) and at landscape (metacommunity) levels. On islands with P. americana, we found that P. americana impacted local avian frugivory networks more on islands with species‐poor plant communities and on isolated islands. Moreover, as P. americana interacted mainly with local core birds (generalists), this indicates reduced seed dispersal of native plants on invaded islands. At the landscape level, P. americana had established strong interactions with generalist birds that largely maintain seed‐dispersal functions across islands, as revealed by their topologically central roles both in the regional plant–bird trophic network and in the spatial metanetwork. This indicates that generalist frugivorous birds may have facilitated the dispersal of P. americana across islands, making P. americana well integrated into the plant–frugivore mutualistic metacommunity. Taken together, our study demonstrates that the impact of plant invasion is context‐dependent and that generalist native frugivores with high dispersal potential may accelerate plant invasion in fragmented landscapes. These findings highlight the importance of taking the functional roles of animal mutualists and habitat fragmentation into account when managing plant invasions and their impact on native communities.
... We found that network dissimilarity in both plant-aphid and aphid-ant networks were high and predominantly driven by species turnover. This result is in line with previous studies of plant, bird and ant assemblages in the same system, which revealed that the community assembly in fragmented landscapes is influenced by environmental filtering and species dispersal abilities [51,84,85]. ...
Habitat fragmentation is altering species interactions worldwide. However, the mechanisms underlying the response of network specialization to habitat fragmentation remain unknown, especially for multi-trophic interactions. We here collected a large dataset consisting of 2670 observations of tri-trophic interactions among plants, sap-sucking aphids and honeydew-collecting ants on 18 forested islands in the Thousand Island Lake, China. For each island, we constructed an antagonistic plant-aphid and a mutualistic aphid-ant network, and tested how network specialization varied with island area and isolation. We found that both networks exhibited higher specialization on smaller islands, while only aphid-ant networks had increased specialization on more isolated islands. Variations in network specialization among islands was primarily driven by species turnover, which was interlinked across trophic levels as fragmentation increased the specialization of both antagonistic and mutualistic networks through bottom-up effects via plant and aphid communities. These findings reveal that species on small and isolated islands display higher specialization mainly due to effects of fragmentation on species turnover, with behavioural changes causing interaction rewiring playing only a minor role. Our study highlights the significance of adopting a multi-trophic perspective when exploring patterns and processes in structuring ecological networks in fragmented landscapes.
... 3) How do island area and isolation affect the AFB of Silver Pheasant (the largest landfowl in this lake system) in continuous versus fragmented habitats? Given that relatively small and isolated islands are characterized by species-poor communities in the TIL system (Si et al., 2017;Zeng et al., 2019), we expect some niches (e.g., the use of arboreal habitat) might become available there, which are occupied by other species on larger or less isolated islands. ...
... Interestingly, in terms of its distribution on the 22 studied islands, the AFB of Silver Pheasant did not occur on small islands (<10 ha), whereas it occurred on all mid-sized islands (10-100 ha) and less frequently on large islands (>100 ha). Silver Pheasants are among the largest pheasant species (~1.2 kg) in this lake system, and may have already been extirpated from small islands because of strong environmental filters (Betts et al., 2019;Si et al., 2017), and previous studies finding only very few records of Silver Pheasant on small islands (Si et al., 2018;Li et al., 2022). In general, large islands (or continuous forests) hold relatively abundant food resources and habitat types, which in turn support more grounddwelling species (Xu et al., 2014;Zeng et al., 2019). ...
... As a result, Silver Pheasant may not need to forage frequently in trees in these habitats. However, some arboreal niches might become available for Silver Pheasant due to the relatively species-poor communities on mid-sized islands (Si et al., 2017(Si et al., , 2018. ...
Habitat changes can alter animal behaviors, especially of large-bodied animals. Landfowl (Galliformes) are a phylogenetically diverse group of large-bodied ground-dwelling birds that are generally considered reluctant flyers. However, some species of landfowl have also been found to forage in arboreal habitats, which could be particularly advantageous under declining habitat quality. However, the prevalence of arboreal foraging behavior (AFB) and how it relates to habitat changes are still unexplored. Here, we reviewed life-history traits associated with foraging behaviors in 305 species of landfowl worldwide and examined the prevalence of AFB across the global landfowl phylogeny. We also collected data from arboreal camera traps on 22 subtropical reservoir islands and six nearby mainland sites in the Thousand Island Lake region of China to assess AFB of Silver Pheasant (Lophura nycthemera), the largest landfowl in this lake system, with island area and isolation. Globally, at least 84 species of landfowl (28%) showed evidence of AFB, with a strong phylogenetic signal. Camera trapping revealed that Silver Pheasant tended to have AFB on small and isolated islands, as evidenced by the increased arboreal sampling efforts. Our study reveals that landfowl's AFB is much more widespread than previously recognized, and suggests the importance of prioritizing large, connected habitats for the conservation of large-bodied animals like Silver Pheasant in the fragmented landscape. Finally, camera trapping emerges as a promising tool for recording landfowl's life history and uncommon behaviors that can help us understand landfowl's threats and aid conservation programs.
