DOI: 10.5061/dryad.rfj6q579r
title: Source pool diversity and proximity shape the compositional uniqueness of insular mammal assemblages worldwide

description: Islands have been the test bed of several theories in community ecology,
 biogeography, and evolutionary biology. Progress within these disciplines
 has given a more comprehensive and mechanistic understanding of the
 processes governing variation in species richness among islands. However,
 it remains unclear whether these same processes also explain variation in
 species and phylogenetic composition among islands. Integrating theory
 from ecology and biogeography, we infer the roles of dispersal, selection,
 and stochasticity on the composition of insular assemblages within
 archipelagos. We further assess the influence of source pool diversity and
 connectivity on the compositional uniqueness of insular assemblages.
 Island systems worldwide. We compiled data on species composition of
 non-volant mammals on ∼200 islands in nine archipelagos distributed
 worldwide from the literature. We used variation partitioning to quantify
 the relative influence of the environment (selection) and geographic
 distance (dispersal) relative to a null model (stochasticity, randomness)
 on taxonomic and phylogenetic compositional turnover within archipelagos.
 We then used a linear mixed model to gain further insight into the
 underlying mechanisms shaping variation in assemblage composition among
 islands at a global scale. Specifically, we assessed the influence of
 source pool diversity, isolation from the source pool, and island
 characteristics on compositional uniqueness. Our results suggest that
 within-archipelago variation in the composition of insular mammal
 assemblages is associated with stochastic or unmeasured processes rather
 than abiotic selection or dispersal limitation. The diversity and
 proximity of the source pool, as well as some island characteristics,
 explained variation in phylogenetic, but not taxonomic, compositional
 uniqueness globally. Within archipelagos, the largely unexplained
 variation in compositional turnover points to the overwhelming influence
 of extinction mediated by ecological drift or other stochastic processes,
 which obscures or overrides the signature of selection and/or dispersal.
 Globally, isolated islands associated with highly diverse source pools
 exhibit high phylogenetic uniqueness whereas well-connected islands
 associated with small source pools show the opposite trend.
 Phylogenetically unique assemblages also tend to occur on islands with a
 small elevational span and low annual temperature variation. Taken
 together, our results suggest that source pool diversity, along with the
 potential for colonization from those pools, plays an important role in
 shaping the composition of insular mammal assemblages worldwide. 
description: This dataset is a set of site by species matrices of the
 presence/absence of non-volant terrestrial mammals on a total of 204
 islands in 9 different island groups. These island groups are as follows:
 Alexander Archipelago (Alx), Gulf of California (Clf), Mediterranean
 Land-bridge (MdtLB), Mediterranean Oceanic (MdtOC), Adriatic Sea (Adr),
 Philippines (Phl), Sundaland (Snd), Maluku islands (Mlk), Melanesia
 (Mln). This data was compiled using published records
 in the primary literature, archipelago-wide checklists, and atlases, and
 cross-referenced community composition among multiple sources (Table S1 in
 the associated article). Domesticated and introduced species were omitted
 when indicated as non-native in the source data or the IUCN Red
 List.
description: <strong>Data and file
 overview</strong> Each data file
 contains a site by species matrix of the presence/absence of non-volant
 terrestrial mammals. All data files are formatted as comma-separated
 values (.csv). In each data file, island names are in rows and species
 names are in columns. A value of 0 indicates absence, and a value of 1
 indicates presence. Data files are named by island group as follows:
 Alexander Archipelago (Alx.csv), Gulf of California (Clf.csv),
 Mediterranean Land-bridge (MdtLB.csv), Mediterranean Oceanic (MdtOC.csv),
 Adriatic Sea (Adr.csv), Philippines (Phl.csv), Sundaland (Ind.csv), Maluku
 islands (Mlk.csv), Melanesia (Mln.csv). All data files
 were created in 2016, and last updated in 2020.
 <strong>Sharing and access
 information</strong> This dataset is
 licensed under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
 license. This dataset is used in the article
 "Source pool diversity and proximity shape the compositional
 uniqueness of insular mammal assemblages worldwide" in the Journal of
 Biogeography, which is in press (DOI will be added when this article is
 published). <strong>Methodological
 information</strong> Species presences
 and absences was compiled using published records in the primary
 literature, archipelago-wide checklists, and atlases, and cross-referenced
 community composition among multiple sources (Table S1 in the associated
 article). Domesticated and introduced species were omitted when indicated
 as non-native in the source data or the IUCN Red List. 
 <strong>Data sources per island
 group:</strong> <em><strong>Alexander
 Archipelago (Alx.csv)</strong></em>  
 Conroy, C.J., Demboski, J.R. & Cook, J.A. (1999). Mammalian
 biogeography of the Alexander Archipelago of Alaska: a north temperate
 nested fauna. Journal of Biogeography, 26, 343-352.<br>   Cook, J.A.
 & MacDonald, S. (2007). Mammals and amphibians of Southeast
 Alaska. MacDonald, S.O. & Cook, J.A. (2010).
 Recent mammals of Alaska. University of Alaska Press.
 <em><strong>Adriatic Sea
 (Adr.csv)</strong></em>   Barun, A.,
 Simberloff, D., Meiri, S., Tvrtković, N. & Tadić, Z. (2015).
 Possible character displacement of an introduced mongoose and     native
 marten on Adriatic Islands, Croatia. Journal of biogeography, 42,
 2257-2269.<br>   Krystufek, B. & Kletecki, E. (2007).
 Biogeography of small terrestrial vertebrates on the Adriatic landbridge
 islands. Folia zoologica, 56, 225.<br>   Kryštufek, B., Murariu, D.
 & Kurtonur, C. (1997). Present distribution of the Golden Jackal
 Canis aureus in the Balkans and adjacent regions. Mammal Review, 27,
 109-114.<br>   <br> <em><strong>Gulf of California
 (Clf.csv)</strong></em>  
 Álvarez-Castañeda, S.T. & Ortega-Rubio, A. (2003). Current status
 of rodents on islands in the Gulf of California. Biological Conservation,
 109, 157-163.<br>   Ceballos, G. (2014). Mammals of Mexico. JHU
 Press.<br> IUCN (2016). The IUCN Red List of Threatened Species.
 Version 2016-3. <br> Millien, V. & Gonzalez, A. (2011). The
 maximal body mass–area relationship in island mammals. Journal of
 biogeography, 38, 2278-2285.
 <em><strong>Sundaland
 (Ind.csv)</strong></em>   Meijaard, E.
 (2003). Mammals of south‐east Asian islands and their Late Pleistocene
 environments. Journal of Biogeography, 30, 1245-1257.<br>   Millien,
 V. & Gonzalez, A. (2011). The maximal body mass–area relationship
 in island mammals. Journal of biogeography, 38, 2278-2285.<br>  
 Suyanto, A., Yoneda, M., Maryanto, I., Maharadatunkamsi, H. &
 Sugardjito, J. (1998). Checklist of the mammals of Indonesia. LIPI-JICA
 Joint Project for Biodiversity Conservation in Indonesia.
 <em><strong>Maluku Islands
 (Mlk.csv)</strong></em>   Meijaard, E.
 (2003). Mammals of south‐east Asian islands and their Late Pleistocene
 environments. Journal of Biogeography, 30, 1245-1257.<br>   Millien,
 V. & Gonzalez, A. (2011). The maximal body mass–area relationship
 in island mammals. Journal of biogeography, 38, 2278-2285.<br>  
 Suyanto, A., Yoneda, M., Maryanto, I., Maharadatunkamsi, H. &
 Sugardjito, J. (1998). Checklist of the mammals of Indonesia. LIPI-JICA
 Joint Project for Biodiversity Conservation in Indonesia.
 <em><strong>Mediterranean (MdtLB.csv and
 MdtOC.csv)</strong></em>   Angelici, F.,
 Laurenti, A. & Nappi, A. (2009). A checklist of the mammals of
 small Italian islands. Hystrix, the Italian Journal of Mammalogy,
 20.<br>   Millien, V. & Gonzalez, A. (2011). The maximal
 body mass–area relationship in island mammals. Journal of biogeography,
 38, 2278-2285.<br>   Vigne, J.-D. (1992). Zooarchaeology and the
 biogeographical history of the mammals of Corsica and Sardinia since the
 last ice age. Mammal Review, 22, 87-96.<br>   <br>
 <em><strong>Melanesia
 (Mln.csv)</strong></em>   Lavery, T.H.,
 Olds, A.D., Seddon, J.M. & Leung, L.K.P. (2016). The mammals of
 northern Melanesia: speciation, ecology, and biogeography. Mammal Review,
 46, 60-76. <em><strong>Philippines
 (Phl.csv)</strong></em>   Heaney, L.R.,
 Balete, D.S., Duya, M.R.M., Duya, M.V., Jansa, S.A., Steppan, S.J. et al.
 (2016). Doubling diversity: a cautionary tale of previously unsuspected
 mammalian diversity on a tropical oceanic island. Frontiers of
 Biogeography, 8.<br>   Heaney, L.R., Dolar, M.L., Balete, D.S.,
 Esselstyn, J.A., Rickart, E.A. & Sedlock, J.L. (2010). Synopsis of
 Philippine Mammals. The Field Museum of Natural History.<br>  
 Heaney, L.R., Dolar, M.L., Balete, D.S., Esselstyn, J.A., Rickart, E.A.
 & Sedlock, J.L. (2011). Supplement to the Synopsis of Philippine
 Mammals. The Field Museum of Natural History.<br>   Meijaard, E.
 (2003). Mammals of south‐east Asian islands and their Late Pleistocene
 environments. Journal of Biogeography, 30, 1245-1257.<br>   Millien,
 V. & Gonzalez, A. (2011). The maximal body mass–area relationship
 in island mammals. Journal of biogeography, 38, 2278-2285.
 <strong>Data-specific information</strong>
 Island names are in rows, and species names are in columns. A
 value of 0 indicates absence, and a value of 1 indicates presence. The
 dataset includes oceanic and land-bridge islands, though each island group
 consists of only one type of island. Gulf of California (Clf),
 Mediterranean Land-bridge (MdtLB), Adriatic Sea (Adr), and Sundaland (Snd)
 consist of land-bridge islands. Alexander Archipelago (Alx), Mediterranean
 Oceanic (MdtOC), Philippines (Phl), Maluku islands (Mlk), Melanesia (Mln)
 consist of oceanic islands. However, the Alexander Archipelago (Alx)
 islands were colonized via dispersal after emerging as a “blank slate”
 after deglaciation approximately 15,000 years ago, and can therefore be
 treated as land-bridge islands in this dataset. Access to complete
 species-level presence-absence data for the entire mammal fauna of
 individual islands limited the selection of island groups.