The Mammals of Northern Melanesia: Biogeography, Systematics And
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opinions, perspectives & reviews ISSN 1948-6596 thesis abstract The mammals of Northern Melanesia: biogeography, systematics and ecology Tyrone Hamilton Lavery PhD Thesis, School of Agriculture and Food Sciences, The University of Queensland, Gatton, QLD 4343, Australia. e-mail: [email protected] Abstract. Northern Melanesia's mammals are poorly known, and perceived deficiencies in faunal records and taxonomic descriptions have, until now, hindered detailed analyses. I examined aspects of biogeogra- phy, systematics and ecology in the region's mammalian faunas. Generalized linear models (GLMs) were used to test for differences in rates of persistence in four orders of mammal on continental shelf islands. Ochiai and endemism indices were used to delineate regions of high endemism and influential biogeo- graphic boundaries. A non-parametric multivariate regression tree and GLMs were used to identify the influences of abiotic variables on mammalian species richness. Genetic sequencing, microsatellite geno- typing, morphological and ecological data were used to determine evolutionary relationships among the widespread insectivorous bat family, Hipposideridae. Northern Melanesia’s islands support mammalian faunas that reflect the poor over-water dispersal abilities of non-volant mammals; lower rates of long- term persistence in dasyuromorphs and diprotodonts; pronounced diversification of the Family Pteropodi- dae; and comparative lack of speciation in insectivorous bat families. Analyses produced a clear hierar- chical classification of Northern Melanesia’s islands based on their physical attributes and mammal assem- blages, providing the first empirical analyses of Northern Melanesia’s and New Guinea’s mammalian zoo- geography, and adding to biogeographic theory at both regional and local scales. Keywords. Dasyurid, evolution, extinction, Hipposideros, island, mammal, Melanesia, Pacific, speciation, zoogeography. Introduction stead been restricted to qualitative descriptions of Northern Melanesia is an ideal location for bioge- species distributions and diversity. This is primarily ographic studies. Analyses of the region’s avifauna due to the perceived deficiencies in the faunal have contributed major advances toward theories record and taxonomic descriptions for the region. of evolution and zoogeography including Mayr’s Almost 20 years following the most compre- biological species concept (Mayr 1942, 1963), and hensive of biogeographic studies, the mammalian Diamond’s ideas on dispersal, gene flow and spe- fauna of Northern Melanesia remains poorly doc- ciation (Diamond 1970, 1974; see Mayr and Dia- umented, and gaps exist in the inventories of is- mond 2001 for a compilation of similar works). lands large and small. Despite important advances Studies of Northern Melanesia’s birds continue to in faunal survey and taxonomy that have occurred spur fundamental advances in biogeographic and since 1995 (e.g. Helgen and Flannery 2004b, evolutionary theory (e.g., Filardi and Moyle 2005, Helgen 2005b, Aplin and Opiang 2011), a compre- Uy et al. 2009). hensive understanding of the region’s mammalian In comparison, the mammals of Northern diversity remains elusive. In the meantime, rapid Melanesia are poorly known. Authors of previous alterations to Melanesia’s natural environments mammalian biogeographic studies for this region are occurring due to mineral and timber extrac- have typically deferred from empirical tests of tion. Also, animal species and environments biogeographic patterns (Koopman 1979, Flannery throughout Oceania are particularly vulnerable to 1995a, 1996). The majority of analyses have in- extinction and decline (Woinarski 2010), and an- frontiers of biogeography 7.2, 2015— © 2015 the authors; journal compilation © 2015 The International Biogeography Society 52 Tyrone H. Lavery — mammals of Northern Melanesia thropogenic disturbance has the potential to non-volant taxa on continental shelf islands; (2) greatly alter species distributions and biogeo- biogeographic patterns across Northern Melane- graphic processes. sia’s oceanic and continental shelf islands; (3) phy- Biogeographic studies of Northern Melane- logenetics of Northern Melanesian Hippo- sia’s mammals present opportunities for novel sideridae; and (4) evolutionary relationships of insight given the unusual dominance of marsupials two sympatric and one allopatric species of the within adjacent continental source pools. The re- Hipposideros diadema species group in Solomon gion also contains a variety of islands, including Islands. In sum, these studies contribute several continental shelf islands, oceanic islands and re- advances in the understanding of biogeographic cently defaunated volcanic islands. These offer patterns, and processes that have led to observed vast opportunities to dissect the roles of abiotic patterns, in the mammals of Northern Melanesia. island variables in shaping mammalian biogeogra- phy. Biogeography My thesis research (Lavery 2014b) com- (1) Long-term persistence of non-volant taxa bined biogeography with systematics and ecology on continental shelf islands to better define the distributions of mammals in An outstanding question relates to the persistence Northern Melanesia (defined as comprising the of non-volant lineages on continental shelf islands Admiralty, Bismarck, D’Entrecasteaux, Louisiade, following isolation by rising sea level. Flannery Solomon and Trobriand Archipelagos; Fig. 1). I ad- (1995a) hypothesized that marsupials have lower dressed four topics: (1) long-term persistence of rates of long-term persistence than placental Figure 1. The region of Northern Melanesia. Archipelagos and selected islands discussed in the text are labelled. Grey shading indicates the approximate configurations of land bridges at a sea level of 120 metres below the pre- sent day level. Bathymetry data used in this reconstruction was sourced from Amante and Eakins (2009). frontiers of biogeography 7.2, 2015— © 2015 the authors; journal compilation © 2015 The International Biogeography Society 53 Tyrone H. Lavery — mammals of Northern Melanesia mammals. To test this hypothesis I compared the itive. Dasyuromorphs are a carnivorous and insec- species richness of Dasyuromorphia, Diprotodon- tivorous lineage, whereas rodents, diprotodonts tia, Peramelemorphia and Rodentia on Australian and peramelemorphs are largely herbivorous. Car- and Papuan continental shelf islands to that pre- nivores require far larger home ranges than herbi- sent within adjacent mainland source pools vores to obtain sufficient resources (Kelt and Van (mammalian zoogeographic provinces; Lavery et Vuren 2001). The implications of this are lower al. 2013a). animal densities, smaller populations and reduced Definition of Australo-Papuan zoogeograph- species survival rates on islands (Heaney 1984). ic provinces required the amalgamation of an ex- This finding is not only a noteworthy and previ- isting classification for Australia (Burbidge et al. ously unacknowledged pattern in the Australo- 2008) with my own, similar classification for New Papuan insular fauna, but also has significant im- Guinea. To classify New Guinea’s zoogeographic plications for mammalian conservation. Australia’s provinces I compiled 4194 distributional records islands are often used as arks to isolate popula- for 264 of New Guinea’s native mammals from tions of threatened mammals from mainland Flannery (1995b), Hitchcock (1997, 1998), Bonoc- threats. Such measures have also been imple- corso (1998), Flannery and Groves (1998), Aplin et mented for conservation of dasyurids such as Tas- al. (1999, 2010), Van Dyck (2002), Helgen and manian devils Sarcophilus harrisii (Jones et al. Flannery (2004a), Helgen (2005a,c, 2007a), Wool- 2007) and dibbler Parantechinus apicalis (Moro ley (2005), Helgen et al. (2008, 2010, 2011), 2003). Acknowledgement of this result will greatly Musser et al. (2008), Helgen and Helgen (2009) benefit long-term conservation planning for dasy- and Musser and Lunde (2009). Records were allo- urids. cated to existing mapped bioregions (Wikramana- yake et al. 2001) and cluster analysis was then (2) Biogeographic patterns across Northern used to allocate bioregions to zoogeographic Melanesia’s oceanic and continental shelf is- provinces. Generalized linear models using the lands procedure GENMOD in SAS 9.3 (SAS Institute Inc., A second outstanding question concerns empiri- Cary, NC) were used to determine rates of island cally describing biogeographic patterns in the persistence in the four mammalian orders as pro- mammalian fauna across the islands of Northern portions of the species present within adjacent Melanesia. Using my own surveys, museum data- zoogeographic provinces. We used the extreme bases and the published literature (Koopman value function (Williams 1995) that employs a 1979, Flannery and Wickler 1990, Flannery and complementary log–log distribution to estimate White 1991, Flannery 1995a, 1996, Bowen-Jones intercept (k), slope (y) and maximum likelihood et al. 1997, Bonoccorso 1998, Anthony 2001, Em- (ML). Proportions of species (S ) present on is- P mons and Kinbag 2001, Heinsohn 2003, Helgen lands were modelled as a binomial response varia- and Flannery 2004b, White 2004, Heinsohn 2005, ble on island area (A): Helgen 2005b, 2007b, Read and Moseby 2006, Helgen 2007b, Heinsohn 2010, Aplin and Opiang Sp = 1 - exp[k + y x log (A)] (1) 2011, Lavery et al. 2013b, 2014, Almeida et al. The order Dasyuromorphia had the lowest 2014, Lavery 2014a) I compiled mammal