Felisa A. Smith - Mammalian Paleoecology: Using the Past to Study the Present

MAMMALIAN PALEOECOLOGY

Using the Past to Study the Present

FELISA A. SMITH

JOHNS HOPKINS UNIVERSITY PRESSBALTIMORE

2021 Johns Hopkins University Press

All rights reserved. Published 2021

Printed in the United States of America on acid-free paper

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Library of Congress Cataloging-in-Publication Data

Names: Smith, Felisa A., author.

Title: Mammalian paleoecology : using the past to study the present/Felisa A. Smith.

Description: Baltimore : Johns Hopkins University Press, 2021. | Includes bibliographical references and index.

Identifiers: LCCN 2020045433 | ISBN 9781421441405 (hardcover) | ISBN 9781421441412 (ebook)

Subjects: LCSH: Mammals, Fossil. | Mammal remains (Archaeology) |Paleoecology.

Classification: LCC QE881 .S64 2021 | DDC 569dc23

LC record available at https://lccn.loc.gov/2020045433

A catalog record for this book is available from the British Library.

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To the fierce, intelligent, and funny women in my life:

my aunt, Rosemary Pellegrini Quarantotti, and

my mother, Maria del Carmen Calvo Herrero,

both of whom I lost over the past year and greatly miss;

and especially,

to my ever-so-talented daughters, who inspire me daily:

Emma A. Elliott Smith, M.S., Ph.D.

Rosemary E. Elliott Smith, M.S.

This project was supported in part by two sabbatical semesters from the University of New Mexico, which were greatly appreciated. Research support was provided by the Integrating Macroecological Pattern and Process across Scales (IMPPS) NSF Research Coordination Network (DEB-0541625) and the National Science Foundation, Division of Environmental Biology grant (DEB-1555525), Beyond Causation: Characterizing the Local, Regional, and Global Impacts of the Late Pleistocene Megafaunal Extinction. As a roving Sabbatarian, I wrote in a number of places, including the Rocky Mountain Biological Laboratory in Gothic, Colorado, which provided a quiet and scenically lovely place to kick-start this project; the University of Wyoming and National Park Service Research Station in Grand Teton National Park, where the views and wildlife were amazing; and both the University of Chicago and University of California. I would be remiss if I forgot the many coffee shops where I lingered for countless hours, and on one occasion knocked a cup of coffee into my laptop. Thank you, all.

I am extremely grateful to my lab group for understanding as I focused on finishing this book instead of other things; I will have more time this year, honestly. In particular, the past year was extremely difficult as I lost both my mother and aunt, both of whom I was very close to. I would especially like to thank Vince Burke at Johns Hopkins University Press, my original editor, for his endless patience as I struggled to prioritize work on this volume. His encouragement was instrumental; my new editor, Tiffany Gasbarrini, and her assistant, Esther Rodriguez, have been equally supportive. Thank you, all!

Finally, I thank my wonderful family (Emma, Rosy, and Scott) for their consistent encouragement, love, and support, and of course, all of my furry friends who have sat upon, chewed on, or merely ignored this volume as it was being written.

MAMMALIAN PALEOECOLOGY

This is a book about ecology in the past and what it can tell us about the present and future. By past, I mean the literal definition as in gone by in time and no longer existing. That is, this is a book about the interactions of organisms and their environment in the time before European settlement of the Americas. In fact, most of this book is concerned with the time before humans came to occupy the Americas, or in some cases, before our hominin lineage even existed on Earth at all.

More specifically, this is a book primarily about mammalian ecology of the past. Restricting mostalthough not allof the discussion in this text to mammals is a strategic move, motivated by their abundant and well-resolved fossil record, the ability to readily identify species and lineages, and the ability to characterize life histories and ecologies. And, I confess, because of an intrinsic bias: mammals are cool. No other group contains the vast array of sizes and life forms they do. Mammals range from the miniscule pygmy shrew (Suncus etruscus), which at 1.8 g doesnt even weigh as much as a single American dime (2.268 g, according to the US Mint), to the largest animal of all time, the blue whale (Balaenoptera musculus), which at almost 180 tons weighs just slightly less than 80,000,000 dimes (Smith and Lyons 2013; ). And, I might add, the blue whale is also twice the size of any dinosaur that ever roamed the Earth. Not only do mammals vary in size by more than eight orders of magnitude, but they also make their home in oceans and streams, in the soil, in the hottest deserts, in the wettest tropics, and in the coldest arctic, and they have successfully colonized the air. In all, mammals display a bewildering and impressive array of diverse life history and ecological characteristics. Whats not to like?

The past has much to teach us; while our current deluge of pressing environmental problemsocean acidification, ecosystem restructuring, and in particular, climate changemay be unprecedented in human history, all have ancient analogs. After all, the Earth is dynamic and has been beset by many perturbations over the past 4.6 Ga. A case in point is anthropogenic climate change. Here, the late Quaternary provides abundant examples for examining the influence of changing abiotic conditions on the distribution, ecology, and evolution of organisms (Graham et al. 1996; Clark et al. 2001; Davis and Shaw 2001; Gavin et al. 2007; Williams and Jackson 2007; Birks and Birks 2008; Louys 2012 and references therein). Evidence from numerous paleoclimate proxies (e.g., pollen, cross-dated tree ring chronologies, ice cores, and other indicators, discussed in ) suggests abrupt climate shifts have occurred with regularity in the past (Allen and Anderson 1993; Dansgaard et al. 1993; Bond and Lotti 1995; Alley 2000; Birks and Ammann 2000). Some, such as the terminus of the Younger Dryas cold episode around 11.5 ka, were sizable, with temperature warming of as much as 510C reportedly occurring within a decade or two (Alley et al. 1993; Alley 2000). This rate of change was actually higher than that expected under all current scenarios of anthropogenic climate change (IPCC 2007) and must have posed significant challenges for organisms. Yet, virtually all species extant today were also present during this time and somehow successfully coped with the consequences of this abrupt warming through a combination of range shifts and adaptation. Indeed, we have recently shown that climate change over the past 65 Ma did not lead to increased rates of mammal extinction, probably because geographic ranges were larger and animals were free to move around (Smith et al. 2018, 2019). Thus, while the underlying cause of human-mediated climate change is different, the magnitude itself is not novel in Earth history.