Susumu Tomiya

Bio: Susumu Tomiya is an academic researcher from University of California, Berkeley. The author has contributed to research in topics: Carnivore & Extinction. The author has an hindex of 7, co-authored 14 publications receiving 2666 citations. Previous affiliations of Susumu Tomiya include Museum of Vertebrate Zoology & Field Museum of Natural History.

Has the Earth’s sixth mass extinction already arrived?

Abstract: Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

Body size and extinction risk in terrestrial mammals above the species level.

Abstract: Mammalian body mass strongly correlates with life history and population properties at the scale of mouse to elephant. Large body size is thus often associated with elevated extinction risk. I examined the North American fossil record (28–1 million years ago) of 276 terrestrial genera to uncover the relationship between body size and extinction probability above the species level. Phylogenetic comparative analysis revealed no correlation between sampling-adjusted durations and body masses ranging 7 orders of magnitude, an observation that was corroborated by survival analysis. Most of the ecological and temporal groups within the data set showed the same lack of relationship. Size-biased generic extinctions do not constitute a general feature of the Holarctic mammalian faunas in the Neogene. Rather, accelerated loss of large mammals occurred during intervals that experienced combinations of regional aridification and increased biomic heterogeneity within continents. The latter phenomenon is consis...

Whence the Beardogs? Reappraisal of the Middle to Late Eocene ' Miacis' From Texas, USA, and the Origin of Amphicyonidae (Mammalia, Carnivora)

Abstract: The Middle to Late Eocene sediments of Texas have yielded a wealth of fossil material that offers a rare window on a diverse and highly endemic mammalian fauna from that time in the southern part of North America. These faunal data are particularly significant because the narrative of mammalian evolution in the Paleogene of North America has traditionally been dominated by taxa that are known from higher latitudes, primarily in the Rocky Mountain and northern Great Plains regions. Here we report on the affinities of two peculiar carnivoraforms from the Chambers Tuff of Trans-Pecos, Texas, that were first described 30 years ago as Miacis cognitus and M. australis. Re-examination of previously described specimens and their inclusion in a cladistic analysis revealed the two taxa to be diminutive basal amphicyonids; as such, they are assigned to new genera Gustafsonia and Angelarctocyon, respectively. These two taxa fill in some of the morphological gaps between the earliest-known amphicyonid genus, Daphoenus, and other Middle-Eocene carnivoraforms, and lend additional support for a basal caniform position of the beardogs outside the Canoidea. The amphicyonid lineage had evidently given rise to at least five rather distinct forms by the end of the Middle Eocene. Their precise geographical origin remains uncertain, but it is plausible that southern North America served as an important stage for a very early phase of amphicyonid radiation.

A New Basal Caniform (Mammalia: Carnivora) from the Middle Eocene of North America and Remarks on the Phylogeny of Early Carnivorans

Abstract: Background Despite a long history of research, the phylogenetic origin and initial diversification of the mammalian crown-group Carnivora remain elusive. Well-preserved fossil materials of basal carnivorans are essential for resolving these issues, and for constraining the timing of the carnivoran origin, which constitutes an important time-calibration point in mammalian phylogenetics.

The educational values of the University of California Museum of Paleontology

Abstract: The University of California Museum of Paleontology (UCMP) maintains the largest university museum fossil collection in the world and promotes research and education at its home, University of California, Berkeley, and far beyond. The museum supplies crucial materials and intellectual resources to a wide variety of university courses, where graduate and undergraduate students gain first-hand experiences in studying fossil specimens in laboratory exercises and class projects. Our specimen-based approach generates greater interest in the subjects and uniquely enhances students’ understanding of biological diversity and evolution. Discovery-oriented class projects often pave the way for scientific publications in professional journals, which contribute to the research mission of the museum. For grades K-12, the museum offers hands-on learning experiences to the public through museum tours and outreach programs at local schools. Further, the highly successful UCMP website relies on the fossil collection to make educational resources in paleontology and evolutionary biology accessible to students of all ages around the world. The museum’s fossil collection is vital to educational programs that disseminate paleontological knowledge and cultivate scientific literacy.

Planetary boundaries: Guiding human development on a changing planet

Abstract: The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system. Here, we revise and update the planetary boundary framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundaries—climate change and biosphere integrity—have been identified, each of which has the potential on its own to drive the Earth system into a new state should they be substantially and persistently transgressed.

Impacts of climate change on the future of biodiversity.

Abstract: Many studies in recent years have investigated the effects of climate change on the future of biodiversity. In this review, we first examine the different possible effects of climate change that can operate at individual, population, species, community, ecosystem and biome scales, notably showing that species can respond to climate change challenges by shifting their climatic niche along three non-exclusive axes: time (e.g. phenology), space (e.g. range) and self (e.g. physiology). Then, we present the principal specificities and caveats of the most common approaches used to estimate future biodiversity at global and sub-continental scales and we synthesise their results. Finally, we highlight several challenges for future research both in theoretical and applied realms. Overall, our review shows that current estimates are very variable, depending on the method, taxonomic group, biodiversity loss metrics, spatial scales and time periods considered. Yet, the majority of models indicate alarming consequences for biodiversity, with the worst-case scenarios leading to extinction rates that would qualify as the sixth mass extinction in the history of the earth.

Defaunation in the Anthropocene

Abstract: We live amid a global wave of anthropogenically driven biodiversity loss: species and population extirpations and, critically, declines in local species abundance. Particularly, human impacts on animal biodiversity are an under-recognized form of global environmental change. Among terrestrial vertebrates, 322 species have become extinct since 1500, and populations of the remaining species show 25% average decline in abundance. Invertebrate patterns are equally dire: 67% of monitored populations show 45% mean abundance decline. Such animal declines will cascade onto ecosystem functioning and human well-being. Much remains unknown about this “Anthropocene defaunation”; these knowledge gaps hinder our capacity to predict and limit defaunation impacts. Clearly, however, defaunation is both a pervasive component of the planet’s sixth mass extinction and also a major driver of global ecological change.

Accelerated modern human-induced species losses: Entering the sixth mass extinction

Abstract: The oft-repeated claim that Earth’s biota is entering a sixth “mass extinction” depends on clearly demonstrating that current extinction rates are far above the “background” rates prevailing between the five previous mass extinctions. Earlier estimates of extinction rates have been criticized for using assumptions that might overestimate the severity of the extinction crisis. We assess, using extremely conservative assumptions, whether human activities are causing a mass extinction. First, we use a recent estimate of a background rate of 2 mammal extinctions per 10,000 species per 100 years (that is, 2 E/MSY), which is twice as high as widely used previous estimates. We then compare this rate with the current rate of mammal and vertebrate extinctions. The latter is conservatively low because listing a species as extinct requires meeting stringent criteria. Even under our assumptions, which would tend to minimize evidence of an incipient mass extinction, the average rate of vertebrate species loss over the last century is up to 100 times higher than the background rate. Under the 2 E/MSY background rate, the number of species that have gone extinct in the last century would have taken, depending on the vertebrate taxon, between 800 and 10,000 years to disappear. These estimates reveal an exceptionally rapid loss of biodiversity over the last few centuries, indicating that a sixth mass extinction is already under way. Averting a dramatic decay of biodiversity and the subsequent loss of ecosystem services is still possible through intensified conservation efforts, but that window of opportunity is rapidly closing.