152 research outputs found

    Joint species movement modeling : how do traits influence movements?

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    Joint species distribution modeling has enabled researchers to move from species-level to community-level analyses, leading to statistically more efficient and ecologically more informative use of data. Here, we propose joint species movement modeling (JSMM) as an analogous approach that enables inferring both species- and community-level movement parameters from multispecies movement data. The species-level movement parameters are modeled as a function of species traits and phylogenetic relationships, allowing one to ask how species traits influence movements, and whether phylogenetically related species are similar in their movement behavior. We illustrate the modeling framework with two contrasting case studies: a stochastic redistribution model for direct observations of bird movements and a spatially structured diffusion model for capture-recapture data on moth movements. In both cases, the JSMM identified several traits that explain differences in movement behavior among species, such as movement rate increasing with body size in both birds and moths. We show with simulations that the JSMM approach increases precision of species-specific parameter estimates by borrowing information from other species that are closely related or have similar traits. The JSMM framework is applicable for many kinds of data, and it facilitates a mechanistic understanding of the causes and consequences of interspecific variation in movement behavior.Peer reviewe

    Global and regional ecological boundaries explain abrupt spatial discontinuities in avian frugivory interactions

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    Species interactions can propagate disturbances across space via direct and indirect effects, potentially connecting species at a global scale. However, ecological and biogeographic boundaries may mitigate this spread by demarcating the limits of ecological networks. We tested whether large-scale ecological boundaries (ecoregions and biomes) and human disturbance gradients increase dissimilarity among plant-frugivore networks, while accounting for background spatial and elevational gradients and differences in network sampling. We assessed network dissimilarity patterns over a broad spatial scale, using 196 quantitative avian frugivory networks (encompassing 1496 plant and 1004 bird species) distributed across 67 ecoregions, 11 biomes, and 6 continents. We show that dissimilarities in species and interaction composition, but not network structure, are greater across ecoregion and biome boundaries and along different levels of human disturbance. Our findings indicate that biogeographic boundaries delineate the world’s biodiversity of interactions and likely contribute to mitigating the propagation of disturbances at large spatial scales.The authors acknowledge the following funding: University of Canterbury Doctoral Scholarship (L.P.M.); The Marsden Fund grant UOC1705 (J.M.T., L.P.M.); The São Paulo Research Foundation - FAPESP 2014/01986-0 (M.G., C.E.), 2015/15172-7 and 2016/18355-8 (C.E.), 2004/00810-3 and 2008/10154-7 (C.I.D., M.G., M.A.P.); Earthwatch Institute and Conservation International for financial support (C.I.D., M.G., M.A.P.); Carlos Chagas Filho Foundation for Supporting Research in the Rio de Janeiro State – FAPERJ grant E-26/200.610/2022 (C.E.); Brazilian Research Council grants 540481/01-7 and 304742/2019-8 (M.A.P.) and 300970/2015-3 (M.G.); Rufford Small Grants for Nature Conservation No. 22426–1 (J.C.M., I.M.), No. 9163-1 (G.B.J.) and No. 11042-1 (MCM); Universidade Estadual de Santa Cruz (Propp-UESC; No. 00220.1100.1644/10-2018) (J.C.M., I.M.); Fundação de Amparo à Pesquisa do Estado da Bahia - FAPESB (No. 0525/2016) (J.C.M., I.M.); European Research Council under the European Union’s Horizon 2020 research and innovation program (grant 787638) and The Swiss National Science Foundation (grant 173342), both awarded to C. Graham (D.M.D.); ARC SRIEAS grant SR200100005 Securing Antarctica’s Environmental Future (D.M.D.); German Science Foundation—Deutsche Forschungsgemeinschaft PAK 825/1 and FOR 2730 (K.B.G., E.L.N., M.Q., V.S., M.S.), FOR 1246 (K.B.G., M.S., M.G.R.V.) and HE2041/20-1 (F.S., M.S.); Portuguese Foundation for Science and Technology - FCT/MCTES contract CEECIND/00135/2017 and grant UID/BIA/04004/2020 (S.T.) and contract CEECIND/02064/2017 (L.P.S.); National Scientific and Technical Research Council, PIP 592 (P.G.B.); Instituto Venezolano de Investigaciones Científicas - Project 898 (V.S.D.)

    Seed Dispersal Anachronisms: Rethinking the Fruits Extinct Megafauna Ate

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    Background: Some neotropical, fleshy-fruited plants have fruits structurally similar to paleotropical fruits dispersed by megafauna (mammals.10 3 kg), yet these dispersers were extinct in South America 10–15 Kyr BP. Anachronic dispersal systems are best explained by interactions with extinct animals and show impaired dispersal resulting in altered seed dispersal dynamics. Methodology/Principal Findings: We introduce an operational definition of megafaunal fruits and perform a comparative analysis of 103 Neotropical fruit species fitting this dispersal mode. We define two megafaunal fruit types based on previous analyses of elephant fruits: fruits 4–10 cm in diameter with up to five large seeds, and fruits.10 cm diameter with numerous small seeds. Megafaunal fruits are well represented in unrelated families such as Sapotaceae, Fabaceae, Solanaceae, Apocynaceae, Malvaceae, Caryocaraceae, and Arecaceae and combine an overbuilt design (large fruit mass and size) with either a single or few (,3 seeds) extremely large seeds or many small seeds (usually.100 seeds). Within-family and within-genus contrasts between megafaunal and non-megafaunal groups of species indicate a marked difference in fruit diameter and fruit mass but less so for individual seed mass, with a significant trend for megafaunal fruits to have larger seeds and seediness. Conclusions/Significance: Megafaunal fruits allow plants to circumvent the trade-off between seed size and dispersal b
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