Now showing 1 - 5 of 77
- ItemHow competitive intransitivity and niche overlap affect spatial coexistence(2021) Yang, Y.Q.; Hui, C.Competitive intransitivity is mostly considered outside the main body of coexistence theories that rely primarily on the role of niche overlap and differentiation. How the interplay of competitive intransitivity and niche overlap jointly affects species coexistence has received little attention. Here, we consider a rock‐paper‐scissors competition system where interactions between species can represent the full spectra of transitive‐intransitive continuum and niche overlap/differentiation under different levels of competition asymmetry. By comparing results from pair approximation that only considers interference competition between neighbouring cells in spatial lattices, with those under the mean‐field assumption, we show that (1) species coexistence under transitive competition is only possible at high niche differentiation; (2) in communities with partial or pure intransitive interactions, high levels of niche overlap are not necessary to beget species extinction; and (3) strong spatial clustering can widen the condition for intransitive loops to facilitate species coexistence. The two mechanisms, competitive intransitivity and niche differentiation, can support species persistence and coexistence, either separately or in combination. Finally, the contribution of intransitive loops to species coexistence can be enhanced by strong local spatial correlations, modulated and maximised by moderate competition asymmetry. Our study, therefore, provides a bridge to link intransitive competition to other generic ecological theories of species coexistence.
- ItemIntroduced species shape insular mutualistic networks(2021) Hui, C.
- ItemDriving factors of community-level plant functional traits and species distributions in the desert-wetland ecosystem of the Shule River Basin, China(2021) Chen, G.G.; Yue, D.X.; Zhou, Y.Y.; Wang, D.; Wang, H.; Hui, C.; Guo, J.J.Groundwater, as the limiting resource in arid ecosystems, can have profound effects on the functional structure and distribution of plant communities. However, studies are too few to unveil the impacts of groundwater depth on plant functional traits in such communities. We collected data on vegetation, topography and soil properties from 180 quadrats (60 trees/shrubs and 120 herbaceous) in the desert-wetland ecosystem of Shule River Basin in Northwest China. We measured 10 key community-level functional traits, together with the resource topography (i.e., groundwater depth) and seven soil properties. We found that the increase of groundwater depth significantly reduced community-level specific leaf area and maximum leaf photosynthesis rate, while boosted leaf dry mass content and leaf thickness. However, the leaf phosphorus content remained relatively stable. By contrast, with the increase of groundwater depth, soil carbon, soil nitrogen, soil phosphorus and total dissolved salts first increased but then declined, while soil pH and soil bulk density exhibited the opposite trend. The soil moisture content decreased drastically with the decline of groundwater. The change in groundwater depth, thus, was found the main driver of species distribution in the arid zone, contributing 21.16%, followed by soil K+(9.94%) and soil total nitrogen content (4.9%), as well as a strong interaction of the three (41.7%). Changes in groundwater depth can thus alter the structure and nutrient enrichment of the soil, which in turn affects the distribution of vegetation through water-soil-plant interactions.
- ItemRecent deforestation drove the spike in Amazonian fires(2020) Cardil, A.; de-Miguel, S.; Silva, C.A.; Reich, P.B.; Calkin, D.; Brancalion, P.H.S.; Vibrans, A.C.; Gamarra, J.G.P.; Zhou, M.; Pijanowski, B.C.; Hui, C.; Crowther, T.W.; Hérault, B.; Piotto, D.; Salas-Eljatib, C.; North Broadbent, E.; Almeyda Zambrano, A.M.; Picard, N.; Aragão, L.E.O.C.; Bastin, J.-F.; Routh, D.; van den Hoogen, J.; Peri, P.L.; Liang, J.
- ItemExtending biodiversity conservation with functional and evolutionary diversity: a case study of South African sparid fishes(2020) Henriques, R.; Mann, B.Q.; Nielsen, E.S.; Hui, C.; van der Heyden, S.Designing marine protected area (MPA) networks has relied primarily on species- or habitat-based measures that assess spatial distributions of biodiversity. Molecular and functional data have the potential to unlock information regarding the evolutionary uniqueness and resilience of natural communities, making phylogenetic diversity (PD) and functional diversity (FD) effective tools for spatial planning. These are, however, rarely used in marine conservation planning. In South Africa, MPAs have been implemented to protect rare and valuable fishery resources, such as members of the Sparidae (seabreams), but have not considered different dimensions of biodiversity, such as its phylogenetic and functional components. Here, we mapped species distributions, phylogenetic relationships and functional features of the Sparidae in South Africa to refine how biodiversity is spatially structured for this species-rich taxonomic group. Our results show strong spatial similarities between PD and FD, suggesting that, for this group, PD is an effective surrogate for functional data. However, there was a mismatch between areas selected with different biodiversity metrics (particularly endemicity levels) and established MPAs, highlighting the need for integrated approaches to conserve this unique marine fauna.