The Baseline Concept in Biodiversity Conservation E-Book
126,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
The Anthropocene era has been marked by such significant human pressure that it has led to the sixth mass extinction. The Baseline Concept in Biodiversity Conservation interprets human domination of the Earth as the process of gradual landscape change, the execution of which is neither linear nor homogeneous. This book is structured around three key questions: Where and when did everything go wrong? How do we define baseline states for biodiversity conservation strategies? How are reference states mobilized in a concrete way through case studies? Today, biodiversity conservation faces a dilemma that this book sheds light on: return to states less modified by humans than today but in a world that has changed significantly; or, let the nature of tomorrow express itself where it still can but without a road map.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 521
Veröffentlichungsjahr: 2022
Ähnliche
Table of Contents
Cover
Title Page
Copyright
Introduction
PART 1: Defining Baselines
1 Temporal Baselines: Finding a Tipping Point in the Past
1.1. Preamble
1.2. Introduction
1.3. Recognition problem: how do we define a new unit of time?
1.4. When did we enter the Anthropocene?
1.5. A temporal baseline on the fringe of the Anthropocene
1.6. Conclusion
2 Spatial Baselines: Is Going Elsewhere Easier Than Going Back in Time?
2.1. Preamble
2.2. Introduction
2.3. What is a spatial baseline?
2.4. Emblematic examples of single- and multi-site spatial baselines
2.5. Conclusion
3 Mapping What is Left of Nature
3.1. Preamble
3.2. Introduction
3.3. Zoning of spaces of perceived wilderness: the wilderness of some is not that of others
3.4. Locating the last wild spots: where is there any baseline nature left?
3.5. Nature areas broken down into facets and gradients: are there tipping points in space?
3.6. Anthropization of nature: summarizing the influence of humans in a single index
3.7. Anthromes: ending the divide between the natural and the anthropogenic?
3.8. Conclusion
4 The Baseline: A Social Construction
4.1. Introduction
4.2. The baseline evolves over time: the shifting baseline syndrome
4.3. How is the baseline constructed?
4.4. Debating the baseline
4.5. Conclusion
4.6. Acknowledgments
PART 2: Using Baselines to Conserve Nature
5 Rewilding by the Return of Ghosts of the Past
5.1. Preamble
5.2. Introduction
5.3. Contemporary ecosystems populated by ghosts?
5.4. Rewilding to repair
5.5. Criticisms and controversies around rewilding
5.6. Conclusion
6 Spontaneous Rewilding through Land Abandonment
6.1. Introduction
6.2. Land abandonment: a form of spontaneous rewilding
6.3. Quantifying and mapping spontaneous rewilding areas related to land abandonment
6.4. Increasing awareness of rewilding areas
6.5. Conclusion
7 Geoprospective: Looking for Potential Scenarios
7.1. Introduction
7.2. The baseline as a shared and objective knowledge base
7.3. The baseline as a way to improve confidence in scenarios
7.4. The baseline for the exploratory evaluation
7.5. The baseline as an objective to be reached
7.6. Conclusion
8 The Place of Ecological Knowledge in Policies for Ecological Neutrality: No Net Loss and Biodiversity Offsetting
8.1. Introduction
8.2. Global overview of the application of the mitigation hierarchy
8.3. The question of a baseline in NNL policies: between ecological and socio-economic perspectives
8.4. Implications of NNL policies for biodiversity conservation: ethical and political perspectives
8.5. Conclusion
PART 3: Examples of the Use of Baselines
9 The Variability of Baselines Mobilized in Littoral Protected Areas: The Anthropocene as a Dividing Line?
9.1. Introduction
9.2. The prehistoric baselines of paleo-rewilding
9.3. The historical baselines of prior states to development intensification
9.4. The contemporary baselines as historical hybrids between nature and culture
9.5. The negotiated, controlled and adapted baselines in the Anthropocene
9.6. The baselines of novel ecosystems in free evolution
9.7. Conclusion: the Anthropocene at the origin of new baselines for Littoral Protected Areas
10 Baselines and French Forests
10.1. By way of introduction: “the legendary virgin forest of Doussard”
10.2. Forestry “cardiology”; forestry “systoles” and “diastoles”
10.3. The baseline of French forests examined through the lens of historical ecology
10.4. French forests in the Anthropocene era: chosen or endured states?
10.5. Baselines and French forests: illustrating our forests together
11 How Can We Maintain Traditional Agro-Pastoral Landscapes?
11.1. Introduction
11.2. How does an agrarian landscape evolve?
11.3. Example of the natural grassland–hedgerows combination
11.4. What exactly do the restored spaces represent?
11.5. What to do then with this forgotten or reinvented past?
11.6. Conclusion
Conclusion
References
List of Authors
Index
Wiley End User License Agreement
List of Tables
Chapter 3
Table 3.1. Proposed definitions of English-language terms related to areas of na...
Chapter 6
Table 6.1. Level 2 CLC nomenclature (source: https://land.copernicus.eu/user-cor...
Chapter 10
Table 10.1. Main characteristics of the phases of the silvigenetic cycle in Fran...
List of Illustrations
Chapter 1
Figure 1.1. The Anthropocene in the geological scale reduced to 24 hours, each o...
Chapter 2
Figure 2.1. The Tagliamento River celebrated for its wildness in a WWF document ...
Figure 2.2. Identification of similar conditions at the study site: A) by typolo...
Figure 2.3. Different approaches to selecting a baseline site(s) for a study sit...
Figure 2.4. The Białowieża Forest is home to iconic species such as the gray wol...
Figure 2.5. The Białowieża Forest as an object of environmental mobilization (so...
Chapter 3
Figure 3.1. Although very difficult to read, Lucas (1964) offers one of the earl...
Figure 3.2. Wilderness areas of the world (source: McCloskey and Spalding (1989)...
Figure 3.3. Web interface to wilderness mapping in Britain (source: Carver et al...
Figure 3.4. Wilderness quality index map (source: European Environment Agency). ...
Figure 3.5. Map of human disturbance in Europe (source: Bennett (1975)). For a c...
Figure 3.6. Global mapping of human disturbance (source: Hannah et al. (1994)). ...
Chapter 4
Figure 4.1. Agro-pastoral landscapes of Mont Lozère (source: N. Salliou). For a ...
Figure 4.2. Typical citations for the role of different factors identified by Ke...
Chapter 6
Figure 6.1. Conceptual diagram of “active” and “spontaneous” rewilding processes...
Figure 6.2. Sankey’s diagram representation of land use area transfers between 1...
Figure 6.3. Mapping of areas of land abandonment. The proportional circles repre...
Figure 6.4. Landscape dynamics of an area of land abandonment detected by cartog...
Chapter 7
Figure 7.1. Illustration of the contribution of multidisciplinary approaches to ...
Figure 7.2. Illustration of the methods that can be used in modeling to respect ...
Figure 7.3. Examples of exploratory scenarios of environmental closure in the Ha...
Figure 7.4. The different variations of the notion of baselines in geoprospectiv...
Chapter 8
Figure 8.1. Global mapping of the implementation of no net loss policies worldwi...
Figure 8.2. Example of the application of an ecological equivalence assessment m...
Figure 8.3. Conceptual approach to the baseline notion in no net loss policies (...
Chapter 9
Figure 9.1. Types of baselines used in coastal protected areas
Figure 9.2. Sea level rise adaptation scenarios for protected areas located on d...
Chapter 10
Figure 10.1. Examples of epiphytism with Rubus ideaus and Epilobium angustifoliu...
Chapter 11
Figure 11.1. Trends in the evolution of hedgerow enclosures and land fragmentati...
Figure 11.2. Evolution of land use and population in metropolitan France between...
Figure 11.3. A great diversity of grassland legacies in the Val d’Authion in 194...
Figure 11.4. Draining and ecological restoration projects in the Authion basin. ...
Guide
Cover
Table of Contents
Title Page
Copyright
Introduction
1 Temporal Baselines: Finding a Tipping Point in the Past
Conclusion
References
List of Authors
Index
Wiley End User License Agreement
Pages
v
iii
iv
xi
xii
xiii
xiv
xv
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
145
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
Series Editor
Françoise Gaill
The Baseline Concept in Biodiversity Conservation
Being Nostalgic or Not in the Anthropocene Era
Edited by
Laurent Godet
Simon Dufour
Anne-Julia Rollet
First published 2022 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
ISTE Ltd
27-37 St George’s Road
London SW19 4EU
UK
www.iste.co.uk
John Wiley & Sons, Inc.
111 River Street
Hoboken, NJ 07030
USA
www.wiley.com
© ISTE Ltd 2022
The rights of Laurent Godet, Simon Dufour and Anne-Julia Rollet to be identified as the authors of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s), contributor(s) or editor(s) and do not necessarily reflect the views of ISTE Group.
Library of Congress Control Number: 2022941253
British Library Cataloguing-in-Publication Data
A CIP record for this book is available from the British Library
ISBN 978-1-78630-888-7
Introduction
I light a fire in the Pyrenean hut after having searched all day, in vain, for the brown bear in the beech–fir forests with their mossy soils. The beast was, however, close to me, the photographic traps placed by the professionals and amateurs of the “réseau ours” would reveal it to me a few days later. It does not matter. What I came for was instead a break from the rest of the world. A “different place”, a little escape from my fellow kind. So, when I see the tracks of an Pyrenean chamois hunter and I glimpse the silhouette of a hiker between two silver fir trees, when I hear the tinkling of the last cowbells of a herd returning or, worse, the horn of a car down in the valley, I pretend not to have perceived anything as it disturbs an almost perfect atmosphere. Because when I arrived at the hut at nightfall, it is fair to say that I was hoping that no candle or headlight was even there.
It is almost shameful to write these lines in a book or say them in a lecture hall as a scientist working in the world of so-called “conservation science”, for several reasons.
The first is that to go looking for bears seems implausible to many in 2021. For most people, this species no longer belongs to French fauna. It is a species that populated French forests thousands of years ago, which still exists in the forests of Siberia or in the great parks of the American West, or, even worse, as an exotic species that was introduced ex nihilo into our mountain forests from Slovenian populations. In any case, there are none or none left. And even if your interlocutor were to believe you, they would ask you in the following second if it is not dangerous to be face to face with the plantigrade. Let us recall the facts: there were at least 52 bears in the Pyrenees in 2019 (Sentilles et al. 2020), it is a Holarctic species, therefore also European (Wilson and Mittermeier 2009), which has never disappeared from French soil (Etienne and Lauzet 2009). Even better, it is a totemic species, a king of animals in Europe for a long time. Pastoureau (2015) reminds us of the existence of mixed Neolithic burials between bears and humans, the presence of bears in the genealogies of Danish kings or the numerous pagan rituals dedicated to the beast (which were also the subject of violent attacks by the Christian Church). Concerning the dangerousness of the species, even if encounters with the animal make the headlines in the regional newspapers, there have been no fatal attacks on humans since the reinforcement of populations in the Pyrenees in the 1990s. There are only reports of intimidation charges from females with cubs. There is therefore a lack of knowledge of the history of the living world. Many know how to date the great fire of London, the tsunami of Lisbon, the fall of the Western Roman Empire, because they have learned, revised and crammed in their books. But how many people know that the bison, the elk or the aurochs were still present on French territory in the 5th–7th, 10th and 12th centuries, respectively (Pascal et al. 2006)? It is even a question of what can be called collective amnesia, documented and theorized as a “shifting baseline syndrome” (Pauly 1995). In just a few generations, we forget what the history of our environment was, taking as a baseline our childhood or, at best, that of our parents or the story of our grandparents. We forget and we get used to it. At most, we are nostalgic for a very recent past. How then can we imagine a return of the living in our societies if they forget that certain species existed alongside them so little time ago? The gray wolf, for example, populated France throughout the Holocene, but its disappearance during a very short time window of 70 years, from the 1920s to the early 1990s (Moriceau 2011), made coexistence with the animal even more unbearable for many, to the point that falsifications of the history of the wolf’s return were invented from scratch to justify the policy of eradicating the species in France1.
The second reason is the sensitivity of the words of this introduction. For many people, science and sensitivity do not always seem to go together. It is difficult to understand that a scientist studies an animal or works for its conservation because they have a sensitive relationship with it. To put it simply: they love the species they are working on. Imagining that in a given place or at a given time, this species is or was present constitutes a comforting spatial or temporal baseline. But one expects rational arguments to legitimize the protection of living things or, quite simply, to explain the choice of one’s study models. A student who wishes to work on whales or great apes will very quickly be qualified by those around them as a “dreamer”. Being transported, animated and passionate is not acceptable. The progressive shift from “protection” to “conservation” (like the passage from the International Union for the Protection of Nature (IUPN) to the International Union for Conservation of Nature (IUCN)), or from “nature” to “biodiversity”, corresponds more or less to the transmission of a great whole to the quantification of elements distinct from one another. Protecting nature for its intrinsic value has become a difficult position to hold. It is more easily protected using functional arguments (because nature provides functions) and instrumental arguments (because nature provides services to human societies2). The few great founding narratives about nature and the wonder of being in nature (e.g., Thoreau 1854) have thus been undermined by several authors3. It would therefore no longer be acceptable to want to protect nature on the grounds that we love it and are amazed by it. It would be even less acceptable to forge a sensitive image of it because, for many, it is necessary to face the evidence: nature would not exist any longer.
This is the third reason that discredits the proposition of a “quest for the bear” (to use Salingue’s (2015) formula) in France in 2021. Nature would no longer exist. The bears I could have seen are reintroduced individuals (originating from Slovenia) or individuals from reintroduced parents. The one that was photographed near me a few days before my visit even has a name. We know the female with which he mated and we even know his offspring whose names were given by the children of the villages of the valley. The forests that I walked through are partly planted by humans and have been cut down. The hut in which I slept is an artifact and is located in the middle of a mountain pasture that exists only because of pastoralism that goes back several centuries. My ascent was along a long-distance hiking trail that is used heavily in the summer and used as a cross-country ski trail in the winter, to the point that the plant communities have been modified. I hid in a clearing that is nothing more than a firebreak maintained for silvicultural purposes. Even the marmot that screamed when a golden eagle circled above me is a species introduced to the Pyrenees in the 20th century (Pascal et al. 2006) to give these mountains the image of the chic resorts of the Alps.
As a result, entire disciplines now balk at talking about nature. As Maris (2018) points out, some may make a “fatal prognosis about the end of nature”. There would not even be nature or wilderness anymore. Works with titles evoking a post-nature or post-wilderness world have followed one another in recent years. Meyer (2006) speaks of the “end of the wild”, Marris (2011) of “post-wild” and Lorimer (2015) of “conservation after nature”. French geographers, on the contrary, have only used the term “nature” or “natural” with quotation marks for a long time (see, for example, Demangeot (1984)). The dissociation between nature and artifice thus seems to be a thing of the past. This form of relativism puts everything on the same level, on the grounds that everything bears more or less the mark of humans.
This last point makes me dizzy. I wish to extract myself from the civilized world and, in doing so, I pass for a non-conformist one with an idealized vision of nature in a society that has obviously cut its ties with it for generations. Indeed, nothing is really natural anymore, except the idea I have of it. But should we stop thinking about this? Is it desirable, joyful or, on the contrary, frightening to find ourselves in this Anthropocene? Is the entry into the human era a journey on a train with no return, launched at full speed, where the only baseline would be the present cut off from the past and with a future as uncertain and unpleasant as the continuation of the sixth extinction of life? Could the Anthropocene be this “terrible failure of humanity” (Descola 2015) or this “one-way trip for humanity to an uncertain future” (Steffen et al. 2011)? Faced with such an observation, the individual may feel helpless (see Cazalis and Granon (2017)), or even plunged into a cynical fatalism by accepting to live in a situation of danger (Beck (1992, 1994) cited in Eckersley (2017)). In a nutshell: What can we do with past baselines in a context of the crisis of the living and increasing domination of humans over the planet?
The first step proposed in this book is to consider the Anthropocene not as a brutal, definitive and indisputable event, but rather as a heuristic metaphor, like Lovelock’s Gaia hypothesis (1979). Above all, it is a concept that helps to illustrate the unprecedented hold of humans on the Earth system. Then, it is a question of discussing the diversity of responses that are being implemented in order to loosen this grip (e.g., conservation, restoration, rehabilitation or compensation) and more precisely a key concept that, explicitly or implicitly, guides these responses: baseline. Thus, rather than remain appalled by the “Anthropocene statement”, this book proposes, on the contrary, to analyze this concept in order to have a critical approach through three parts.
Is the hold of humans monolithic? Monolithic in space first. Social scientists thus remind us that many societies have had little or no involvement in the changes of the Anthropocene (see Lowenhaupt Tsing 2017; Malme 2017; Glowczewski and Laurens 2018) so much so that some authors have preferred to speak of the “Capitalocene” (Haraway 2015; Bonneuil 2017), the “Technocene” (Hornborg 2015), or the “Anglocene”4 (Fressoz 2017). Monolithic in time then. Did the Anthropocene arrive very suddenly? Bonneuil and Fressoz (2013) thus remind us that the “Anthropocene event” itself and its conceptualization are not recent. Therefore, can we identify baselines as tipping points in time during which changes in the hold of humans on the Earth took place?
What do we want to do once we have identified possible baselines? Are these changes necessarily irreversible? Can they be stopped? Are there no possible returns to past baselines or should we, on the contrary, let nature take its course, or even welcome the arrival of hybrid “new ecosystems”?
Finally, how can these reflections be translated into practice regarding concrete cases? Using the example of the coastline, forests and the countryside, we try to understand how this notion of baseline can be mobilized.
The aim of this book is to offer geographers’ multidisciplinary views on the concept of baseline. Indeed, the latter questions the relationship that societies have simultaneously with temporal dynamics, spatial diversity and the way of living in nature, all themes of reflection embraced by the geography of nature.
Chapter written by Laurent GODET.
1
Including by politicians like Christian Estrosi, claiming that the species had been “artificially reintroduced” (sic) by state officials and park rangers in Mercantour Park. His conviction for defamation in 2015 was then overturned on appeal two years later.
2
For a critical approach to ecosystem services, see Maris (2014).
3
Peter Kareiva, one of the most fervent representatives of the New Conservationists, strives, for example, to point out inconsistencies in Henry David Thoreau’s story. In a style mixing arrogance and contempt, he tries to underline all the mawkishness that there would be in the account of the person who cut themselves off from the city by staying in a cabin on the edge of Walden Pond in the middle of the 19th century.
4
In the 20th century, the United Kingdom and the United States alone accounted for more than half of greenhouse gas emissions until very recently (Fressoz 2017).
PART 1Defining Baselines
1Temporal Baselines: Finding a Tipping Point in the Past
1.1. Preamble
Leaving Paris for Mansle, a small village in the Charente region of France, Rachel drove across France on a hot July day. Her two children were sleeping in the back seat. They fell asleep after a few minutes, probably tired from the monotony of the Beauce countryside. They were not thrilled by the sight of this French granary and biological desert, where only a few intrepid Kestrels brightened up the landscape every 5 or 10 km with their Flight of the Holy Spirit over invisible prey. Four hours later, arriving in the courtyard of her elderly retired parents’ Charentais farm, Rachel saw her mother who exclaimed:
Did you wash the car in Ruffec? The windshield is all clean!
The children did not understand their grandmother’s remark. She quickly explained to them that in the past, when we drove in the summer, we had to clean our windshields, because there were swarms of insects that crashed into them. All of this vaguely reminded Rachel of something and she questioned her mother:
Do you know when exactly? I mean… do you know when we stopped having these bugs coming crashing into cars?
I don’t remember, but it must have been before we sprayed everything, replied the grandmother.
Sprayed everything? asked Rachel
Yes, before we put all the chemicals in the fields. Now, even when Thierry harvests, it’s only dust, no bugs. There are not even grasshoppers anymore!
The swarms of insects that crash into cars and spring up from the wheat at harvest time seem to belong to another time, the grandmother’s apparently, not really that of the mother. As for the children, it all belongs to science fiction. Clément, five years old, imagined that his grandmother’s childhood probably coincided with the beginning of the extinction of the dinosaurs. But all this raised questions for Rachel who mumbled softly:
When exactly did we stop having insects and therefore birds and other animals? Was it the same as global warming? Was it at the same time?
Rachel did not get an answer from her mother, who was obviously busier swatting a fly that had landed on the oilcloth of the kitchen table. Looking away, she wondered when everything changed. What if “it was better before” was not just a formula passed down from generation to generation? What if there really was a moment, a clearly identifiable period, when humans began to destroy everything?
1.2. Introduction
Since the first classifications of living beings by Carl von Linnaeus (18th century), humans have placed themselves above other species. Since Darwin, we have known that this place has been usurped, Homo sapiens being only a member of the great community of living beings among the two million or so species that he strove to describe and classify. In this context, is it just as pretentious to attribute to Homo sapiens, the name of a new period of the age of the Earth: the Anthropocene?
At first sight, everything alines to say that it is not. What makes our species original is not the fact that it is more intelligent, “more evolved”, that it speaks, has a sense of humor or even plays. What makes our species original is its unique ability to modify the Earth system as a whole, to the point that our species is a major force that is profoundly modifying the atmosphere, the lithosphere, the hydrosphere, the cryosphere or the biosphere (see, for example, Harari (2015) for a general overview). Regarding the atmosphere, humans have emitted 555 petagrams of carbon into the atmosphere since 1750, generating a concentration of this gas not seen in at least 800,000 years (Lewis and Maslin 2015). This concentration of CO2 has led to ocean acidification, also not seen in at least 300 million years (Lewis and Maslin 2018). Successive IPCC reports confirm that the emission of all greenhouse gases released by humans is changing the Earth’s climate, leading to a rise in temperature and sea levels. The consequences on the cryosphere are major: the melting of the Greenland ice cap (with a loss of more than 200 gigatons of ice per year (GIEC 2013)) and that of Antarctica (50 gigatons per year (GIEC 2013)) are striking evidence of this warming. From a biosphere perspective, species extinction rates are 100–1,000 times higher than historical extinction rates (Barnosky et al. 2011) and the globalization of trade has led to a great mixing of species across the globe and biotic homogenization (Baiser et al. 2012).
As Magny (2021) reminds us in his excellent synthesis on the Anthropocene, this capacity of humans to modify the entire planet they inhabit was identified very early on. At the end of the 18th century, Buffon, in The Epochs of Nature, identified seven epochs, the seventh being the one in which the power of humans assisted that of nature. Jenkyn, an English clergyman, spoke of anthropozoic as early as 1854, a term taken up by the Italian geologist and priest Stoppani in 1873, while Vernardsky, Theilhard de Chardin and Le Roy spoke of the noosphere, as, according to Vernardsky, the new phase of the Earth where human cognition transforms the entire biosphere (Magny 2021). Several authors questioned, however, whether humans have a sufficiently marked and identifiable impact to speak of an obvious geological time unit. According to Lewis and Maslin (2015), however, the Anthropocene must be defined on the same criteria as all the previous eras, because otherwise the Anthropocene would be merely an ideology.
In this work, which deals with the notion of baseline and conservation of nature, the question is therefore raised not only about the relevance and possibility of identifying the beginning of a human hold on the Earth, but also the various dates that can be considered as the “tipping point(s)” from which this hold clearly began. In parallel to the anthropogenic dimension as a factor of change, the temporal baseline also questions the existence of a partial reversibility of the functioning of ecosystems or their functionality.
1.3. Recognition problem: how do we define a new unit of time?
The geological time scale is composed of different chronostratigraphic units (corresponding to sedimentary layers of the Earth’s crust) combined with geochronological units (corresponding to time intervals). The geological time scale was standardized by the International Commission on Stratigraphy in 1974. Geochronological units are eons, eras, periods, epochs (see Figure 1.1) and stages, each with opposing chronostratigraphic intervals (eonothems, erathems, systems, series, stages and substages) (see Ogg (2004); Gradstein et al. (2012)). All units of the Phanerozoic Eon (542 million years ago to the present day) and the last Proterozoic period (Ediacaran, 632–542 million years ago) are defined by a Global Boundary Stratotype Section and Point (GSSP); commonly referred to as the golden spike on the charts; the Archean and Proterozoic eons (i.e., the entire Precambrian interval excluding the Ediacaran), prior to 632 million years ago, are subdivided into absolute ages (Global Standard Stratigraphic Age or GSSA) due to the absence of fossils. The golden spikes, therefore, define a specific point at the lower limit of a geological stratum, which must be caught between two golden spikes.
The identification of the limits between each of these time units requires the individualization of stratigraphic layers, and thus of disruptions caused by global events; Ogg (2004) adds in his text “when possible”. The challenge is to determine temporal intervals with significant changes in sedimentation, paleoenvironment and paleontological characteristics. It is, therefore, a matter of linking series of events of local or regional scale to a global scale (Cohen et al. 2013). However, the definition of the different units of the geologic time scale is done under the assumption that certain principles are met, including the principles of:
– continuity (equivalent age throughout the same stratigraphic layer defined by its lithological facies);
– actualism (past formation processes are equivalent to the present);
– paleontological identity (the discovery of identical fossils in two geological layers implies that they have the same age);
– superposition (apart from structural change, a layer is younger than the one it covers and older than the one that covers it);
– horizontality (the sedimentary layers are deposited horizontally; only a deformation subsequent to its deposition can disturb this position);
– intersection (the faults observed in the sedimentary layers are posterior to them);
– inclusion (the rocks observed in the sedimentary layers are prior to them).
The geological scale is thus made up of “single time surfaces”, each with a precisely synchronous level that can be traced all around the Earth (Zalasiewicz et al. 2015). Yet, these principles are hardly ever respected, since (i) only more or less residual traces of these time units are traceable and (ii) most of the events constituting the different units are progressive, covering temporalities of thousands to millions of years (formation of mountain ranges, opening of the ocean, etc.) that include brief events (volcanic eruption, meteorite fall, etc.). Thus, in most cases, it is a matter of identifying the least poor range of indicators (Zalasiewicz et al. 2015) that leaves room for several arbitrary decisions in the absence of strict criteria, or the adoption of eclectic criteria (see Lucas (2018) for a history of the thinking leading to the constitution and revision of the geologic time scale). In the end, Lucas (2018) reminds us that the chronostratigraphy approach and method suffer from inconsistency, arbitrary decisions, reductionism, instability, opposition between global and local scales, imprecision and power struggles over the naming of different geological strata. The proposal of the Anthropocene as a chronostratigraphic or geochronological unit is an example of these power struggles. Indeed, the naming of geologic time scale units is subject to a vote by all members of the International Commission on Stratigraphy; however, the Anthropocene is not yet demonstrated by evidence of stratigraphic unity or boundaries recorded in lake or ice cores, or in other records at a global spatial scale (Finney and Edwards 2016).
Figure 1.1.The Anthropocene in the geological scale reduced to 24 hours, each of its subdivisions corresponding again to 24 hours (eons, eras, periods and epochs, then Anthropocene), showing the infinitesimal duration of the human impact on the environment during geological time, yet of considerable magnitude in its intensity
1.4. When did we enter the Anthropocene?
While the stratigraphic approach struggles to propose a definitive answer to the existence of a particular geological period, other approaches have been mobilized to define a date of entry into the Anthropocene. The proposals for dates have been relatively numerous (Gemenne and Rankovic 2019) because the authors have sometimes emphasized the modification of one of the planet’s components rather than another (very often the atmosphere and the biosphere, and also, to a lesser extent, the lithosphere or the hydrosphere). Also, they have been able to use different criteria to measure these changes (e.g., for the atmosphere: the carbon dioxide, methane or nitrogen content; for the biosphere: the disappearance of species in one taxonomic group rather than another; for the lithosphere: the presence of radionuclides or micro-plastics, etc.). We present here, in chronological order, the main dates used in the literature to identify the beginning of the Anthropocene (see Figure 1.1).
1.4.1. 50,000 years BP: the end of the Pleistocene and the extinction of megafauna
Extinction crises, generally understood as the global disappearance of three quarters or more of the species in a short period of time, are strong indicators of major abrupt changes on a planetary scale. They are, in themselves, moments of change in the Earth’s system because a large part of the biosphere is profoundly modified. The extinction crises of the living world are also revealing because they represent one of the consequences of changes in a set of components of the planet. The five extinction crises that followed one another during the history of the Earth are indeed marked by important climatic changes, sometimes sudden marine transgressions and regressions, tectonic and volcanic phenomena, asteroid impacts or massive anoxia of water masses; all these modifications are intimately linked to one another (see Barnosky et al. (2011)).
The beginning of the sixth extinction crisis that we are currently experiencing can be located at the end of the Pleistocene with the extinction of megafauna (see Chapter 5 of this book). It was during this period that animals weighing more than 44 kg as adults (see Martin (1984)) disappeared in fairly short periods of time. The origin of these disappearances is still debated. Several camps are in conflict, with, schematically, the proponents of an anthropic origin (Martin 1967, 1984), those of an environmental origin (see, for example, Grayson and Meltzer (2003) concerning the case of North America) or those favoring a combination of the two (see, for example, Elias and Schreve (2007)). The debate is likely to remain sterile in the absence of dating and close examination of new fossils.
The end of the Pleistocene can thus be seen as the beginning of the Anthropocene if we consider that it is indeed the beginning of the sixth extinction crisis of living organisms and that its origin is essentially anthropogenic. In addition to the question of the anthropogenic character of the crisis, the identification of this period as the starting point of the Anthropocene poses a problem because the sixth crisis is currently underway and even seems to be accelerating and affecting an ever larger number of taxonomic groups. It is therefore difficult to identify the limits of a crisis of which we do not yet know everything and whose climax is perhaps still to come. The speed of this crisis is, however, indisputable. While the previous biodiversity crises were generally spread over several million years (with the exception of the Cretaceous crisis, during which the impact of the asteroid in the Yucatan probably had rapid effects), the sixth crisis is already identifiable in only a few thousand years.
1.4.2. 5–7000 years BP: the Neolithic and the increase of methane and CO2
While hunter-gatherers were most likely responsible for, or at least contributed to, the disappearance of the Pleistocene megafauna, the changes made during the Neolithic period were even more significant. This period marked a change in the way of inhabiting and exploiting the Earth, and thus in the intensity and extent of the modifications brought by humans to the planet. The sedentarization of human populations, the clearing of land, the development of agriculture, associated with the storage of harvested products and the beginning of animal husbandry were changes that took place in several parts of the world and at dates beginning at the earliest around 11,000 years BP in the Near East or 6500 years BP in Europe.
The Early Anthropogenic Hypothesis (EAH) was first published nearly 20 years ago (Ruddiman 2003), stating that the influence of humans on climate began very early, with the increase in methane concentrations 5,000 years ago due to anthropogenic emissions from large-scale rice cultivation and cattle ranching, and the increase in atmospheric CO2 that began 7,000 years ago due to deforestation.
The anthropogenic origin of the methane increase has been fairly uncontradicted (but still see the orbital forcing hypothesis by Singarayer et al. (2011)). Evidence was published by Fuller et al. (2011), who mapped the development of rice cultivation in Asia between 5,000 and 1,000 years ago. They estimated that CH4 emissions from northern rice fields were responsible for 70% of the increase in atmospheric CH4 recorded in ice cores during this time interval. Today, the IPCC is also adopting the Ruddiman hypothesis (see Ciais et al. (2013)).
In contrast, the hypothesis of increased CO2 7,000 years ago due to humans has been more controversial. Ruddiman et al. (2020) defend this hypothesis on the basis of demographic data. Early demographic data documented a global human population of the order of a few million people 10,000 years ago (McEvedy and Jones (1978) cited in Ruddiman et al. (2020)), followed by a doubling of this population every thousand years, bringing the world population to over a billion people a few centuries ago. According to this progression, the planetary human population was relatively small 7,000 years ago and would therefore not have started its spectacular progression. However, recent archaeological studies conducted in China have shown a completely different population dynamic (see, for example, Li et al. (2008); Hosner et al. (2016)) with a marked demographic increase as early as 7,000 years BP, at a time when the hunter-gatherers of this region of the world became farmers, and began to practice deforestation in order to establish crops and pastures. In Europe, numerous archeological sites have been uncovered, corresponding to dates between 5,000 and 7,000 years BP, coinciding with the first settlements of farmers and herders (Ruddiman et al. 2020). This increase in population in Europe and China, two major population centers at that time, accompanied by significant deforestation, lends credence to the increase in anthropogenic atmospheric CO2 during the same period.
However, the amount of CO2 emissions has been much debated. Some authors (see Table 1 in Ruddiman et al. (2020) for a list of these studies) consider Ruddiman’s (2003) estimates to be overestimated by a factor of 5. It is clear that extensive ancient deforestation occurred at several points around the globe, including after 6,000 years BP in Europe (Fyfe et al. 2014; Roberts et al. 2018). Deforested areas remain difficult to assess because they are based on average areas estimated to be needed by a farmer, and what is meant by “deforested area” is also subject to controversy (e.g., either only areas converted to crops and pasture, or partially or temporarily deforested areas – see Houghton and Hackler (2003)). In contrast, paleoenvironmental reconstructions provide evidence for a significant transformation of valley floor morphology in response to deforestation in many European rivers (Lespez 2012; Brown et al. 2018).
1.4.3. 1610: “Columbian exchange”, low CO2 level and cooling of the Little Ice Age
It is the year 1610 that is promoted by Lewis and Maslin (2015, 2018) as the official start date of the Anthropocene. According to these authors, the 17th century was marked by visible evidence of the connection of previously separated continents and oceans, and thus an exchange of species across the world. This “Columbian exchange” (a term coined by Crosby (2003) to describe the exchanges between Old and New Continents that occurred following the “discovery” of America by Christopher Columbus in 1492) is well identified in stratigraphic observations and archaeological materials. However, Lewis and Maslin (2018) prefer to follow the prevailing recommendations of the geological community, and thus do not use a biostratigraphic marker as the GSSP of the Anthropocene. They therefore advocate a GSSP based on a change in atmospheric composition, specifically the tipping point in the amount of atmospheric CO2 due to the arrival of Europeans in America. Following their arrival, the Europeans unwittingly decimated the native populations mainly by importing the smallpox virus, which led to the abandonment of agricultural land and the development of a vegetation cover that stored a significant amount of carbon, while causing a drop in carbon in the atmosphere. This drop has in fact been well recorded in ice cores, particularly from Antarctica (Dull et al. 2010). Lewis and Maslin (2015, 2018), therefore, use the minimum CO2 values from this period recorded in the Law Dome ice core, 1610, to give an Anthropocene start date. This corresponds to the coldest period of the Little Ice Age. The year 1610 is, therefore, a tipping point where the fauna and flora of several continents that had been separated until then mixed, and also where the CO2 reached a very low level and temperatures were particularly low.
1.4.4. End of the 18th century: the First Industrial Revolution
One of the most commonly cited dates for the beginning of the Anthropocene corresponds to the end of the 18th century and the beginning of the 19th century (see Bonneuil and Fressoz (2013)). This is the period proposed by Crutzen, to whom the name of this new phase of the Earth’s geological history belongs. For Crutzen (2002), it is indeed from the end of the 18th century that we note the beginning of an increase in the atmospheric concentration of CO2 and methane. This corresponds to the patenting of the steam engine by James Watt in 1784 and the entry into the First Industrial Revolution. In Europe, this period marked the transition from slow population growth, an agricultural society, and the use of energy derived primarily from human muscle power and wood burning to rapid population growth, an urban and industry-oriented society processing fossil fuels (Zalasiewicz et al. 2015).
1.4.5. The mid-20th century: the great acceleration and the fallout of radionuclides
In the aftermath of World War II, the mid-20th century was marked by a major population boom, economic growth and environmental changes (Zalasiewicz et al. 2015). This period is generally referred to as the “Great Acceleration” (see Steffen et al. (2007)). It is characterized by several aspects: a major increase in CO2 emissions since the pre-industrial era (higher levels of CO2 were recorded in the Pliocene, four million years earlier), the democratization of the automobile, agricultural intensification with significant use of chemical fertilizers and a globalization phenomenon (Zalasiewicz et al. 2015). The environmental change generated by these changes far beyond just the inhabited urban centers of humans has been the basis for identifying a Holocene/Anthropocene divide (see Wolfe et al. (2013)). McNeill and Engelke (2016) wrote an entire book entitled The Great Acceleration: An Environmental History of the Anthropocene Since 1945. In that book, despite the consensus of the illusion of determining a precise date at the beginning of the Anthropocene, the authors nevertheless propose to consider the middle of the 20th century (around 1945–1950) as the beginning of this period. Although they point out that humans have always modified their environment, the authors successively review: energy and human population, climate and biodiversity, cities and the economy, the Cold War and environmental culture, in order to demonstrate that the influence of humans took on a whole new dimension from 1945 to 1950. It is from this period that the concentration of CO2 reached levels never reached in 870,000 years, the nitrogen cycle was disrupted (see Canfield et al. (2010)1), and the anthropogenic impact on the biosphere took on a major magnitude, notably through the unprecedented growth of cities or the massive construction of dams, the acidification of the oceans or the accumulation of plastic debris. They point out that if the Great Acceleration on the one hand and the Anthropocene on the other coincide in time, it will not last. The Great Acceleration will come to an end: the human population cannot continue to grow and the use of fossil resources is almost at an end. On the contrary, the Anthropocene will continue longer, because for McNeill and Engelke (2016): “Indeed, even if every human immigrated to another planet tomorrow, our impacts of the past few generations will linger for millennia in the Earth’s crust, in the fossil record, and in climate.”
Finally, to support the idea of the beginning of the Anthropocene around the 1950s, let us point out that the votes of the working group on the Anthropocene of the International Commission on Stratigraphy made known on May 21, 2019 that the basis of the Anthropocene lies on the stratigraphic signals of the mid-20th century.
The decade that followed, the 1960s, has also been proposed as the starting point of the Anthropocene. Specifically, the year 1964, the year of peak radionuclide fallout, has been proposed as the GSSP by several authors (Lewis and Maslin 2015, 2018; Waters et al. 2016) and referred to as Bomb Spike (Lewis and Maslin 2018). For Lewis and Maslin (2018), this radionuclide fallout is recorded in many repositories all over the Earth and will likely be present for millions of years. Lewis and Maslin (2018) believe that they coincide well with the Great Acceleration, and thus they are somewhat at odds with Zalasiewicz et al. (2015) or McNeill and Engelke (2016) for whom, as noted, the Great Acceleration began instead in the 1940s–1950s.
1.5. A temporal baseline on the fringe of the Anthropocene
By definition, the Anthropocene concept focuses on the question of the anthropization of environments. The tipping point notion leads to the search for an absolute baseline in the past, i.e., a state free of any anthropic influence or with a minimal level of transformation. Nevertheless, another use of the notion of baseline exists, without necessarily considering its natural character.
Indeed, a past biophysical functioning can be considered as a baseline if it corresponds to a socially desired functioning for the services it provides or for its relative stability. Thus, the work of the Mountain Land Restoration services in France (Restauration des Terrains en Montagne, RTM) was implemented as early as the 19th century to reduce the risks associated with sediment production (river bed embankment and associated flood risks, slope instability, etc.). It is a question of “restoring to the cleared land its primitive adhesion” (Dugied (1818) cited in Combes (1989); Hall (2005)). RTM mobilizes a state prior to agricultural clearings that is considered more socially acceptable because it has the advantage of reducing exposure to hazards (through a management perspective that is very close to engineering); the acceptance of RTM interventions is therefore not linked to the prospect of a return to a certain naturalness (Brugnot 2002).
A baseline can also correspond to a landscape, a functioning, characteristics that are distinguished by their rarity and their intensity. For example, in the French or Italian Alps, braided rivers are currently the subject of much attention because they generate emblematic landscapes, present intense biomorphological processes and shelter particular plant and animal species. However, their establishment is partly based on anthropogenic modifications of the mountain slopes during the 19th century (Gautier 1994; Roche et al. 2005; Liébault et al. 2010). Today, this fluvial style is becoming scarcer, in part due to reduced sediment production. Among the causes of this sediment deficit, spontaneous reforestation following the decrease in anthropogenic pressures (e.g., cessation of grazing) is most often perceived or implied as a limit to the possibility of restoring a river to its most intense morphological functioning, and thus “idealized”, or even as an alteration of a process rather than a return to more naturalness (e.g., Surian and Rinaldi 2004; Brousse et al. 2019). The baseline of these systems was often sought in the 19th century, a period in which direct anthropic pressure was nevertheless the most significant (Hall 2005).
1.6. Conclusion
To define the Anthropocene is to admit that humans mark a period in the history of the Earth. This is not arrogance, and this is for two reasons. First, it is about recognizing the facts (changes in the atmosphere, the lithosphere, biodiversity, etc.); but it is also about recognizing the negative consequences of our species’ actions on all the other compartments of the Earth system, as well as on our own species. The only arrogance is probably to “put all humans in the same boat” of the Anthropocene: they do have a common destiny, but only a fraction of humanity is at the origin of it.
The first difficulty in defining the starting point of the Anthropocene is related to the extremely recent character of all the events we have been able to list (from the end of the Pleistocene to the 1960s). The data concerning the last few thousand years are much more diverse and abundant than the older ones, which can lead to a much finer identification of recent events compared to the older ones. The second major difficulty in identifying the Anthropocene is that it is the contemporary period. How can we then know if the greatest changes are not yet to come? How can we analyze and conclude the identification of a period that is not yet over?
The question of the irreversibility of harmful, anthropogenic actions also arises. The lockdown of spring 2020 due to the Covid-19 pandemic and the almost total and abrupt ceasing of human activities on a global scale, at least concerning the western world, has shown that the impact of humans is not necessarily permanent on certain aspects (reduction of the pollution of the Venice lagoon; return of the observation of great fauna; decrease in urban smog, etc.). What is the temporality of the chronostratigraphic limits between the different geological layers? What is the duration of the “sudden changes” justifying the passage from one layer to another?
In the end, the Earth is 4.54 billion years old; Homo sapiens appeared 300,000 years ago; they are therefore present on only 0.0066% of the geological scale and have undoubtedly profoundly modified the Earth system. If we consider the low limit of the beginning of the Anthropocene (around 50,000 years ago with the extinction of the megafauna), it represents 0.00011% of the geological scale. Considering its high limit (around 1950, or 70 years), it is 0.0000015%. Brought back to a scale of 24 hours, these values represent 5.7–0.09 seconds, i.e., for the low value, hardly the duration of a blink of the eye.
Chapter written by Laurent GODET, Simon DUFOUR, Anne-Julia ROLLET and Armelle DECAULNE.
1
The invention of the Haber-Bosch process in the early 20th century, enabling the conversion of atmospheric nitrogen to ammonia for soil fertilization, has altered the global nitrogen cycle so much that the closest geological comparison in modern times that can be suggested refers to events that occurred about 2.5 billion years ago.
2Spatial Baselines: Is Going Elsewhere Easier Than Going Back in Time?
2.1. Preamble
We completed our PhD in the early 2000s, and during this time, we attended several conferences dedicated to river management, ecological restoration of wetlands, the historical geography of forests, etc. Many of the discussions held at these events were related to the baseline question, either during the presentation sessions or during more informal moments. What was the content of the exchanges? Without reporting on all of them, we will note a common feature of most of these discussions: they addressed the question of how the objectives of a management plan or restoration action are defined. And almost systematically a debate followed: “for us it is quite simple, because we have data on the state of our wetland site before it was transformed by human activities”, “for us it is more difficult, since our site has been occupied by humans for several centuries, so we have surveyed other comparable, but more natural, sites”, “we rely on models that predict the type of environmental conditions and biological communities that should be present without anthropogenic pressure”, etc. It seems to us that there was some confusion due to different visions of what is “natural”, the history of sites, what is a comparable site, etc. This chapter aims to propose elements of clarification that we would have liked to have had two decades ago in order to facilitate exchanges.
2.2. Introduction
The baseline has often been defined as a state without disturbance, i.e., without pressure from human activities (e.g., NRC 1992). Therefore, the first impulse was to look for these baselines in the past, before anthropic pressure profoundly transformed the bio-physical functioning of the environments. If this reference to the past fits perfectly with the old adage “it was better before”, the quest for what the English-language bibliography describes as a pristine state quickly encountered numerous obstacles. These obstacles appear both in the construction of the baseline and in its application. Regarding the first point, it is, for instance, difficult to obtain historical data, which are scarce and often imprecise (Schletterrer et al. 2014), and to temporally define the baseline period (how far back in time?). The second point concerns the relevance of the concrete use of these historical baselines as a management tool in contexts where anthropic pressures are multiple, old, and when the dynamics of environmental conditions no longer enable the realization of this baseline. For example, Wyzga et al. (2012) were able to observe, in Polish Carpathian streams, significant reductions in flows and sediment inputs related to environmental changes within watersheds characterized by very little direct anthropogenic influence. Even non-anthropogenic ecosystems are dynamic! Thus, while the historical approach provides relevant information on the trajectory of a site, restoring a system to its pre-disturbance conditions is, strictly speaking, impossible in most situations.
To get around these limitations, another approach is to look for baseline systems elsewhere in space, in areas that are still relatively preserved, or where there is a consensus on the quality or integrity of current biophysical functioning. However, behind this apparent simplicity, the spatial dimension is not simpler or smoother than the temporal dimension, and this raises many eminently geographical questions such as the representativeness of the selected sites, the spatial scale at which these baselines should be sought (sites? eco-regions?) or the modalities for integrating, or not, the anthropic influence on the selected sites.
In this chapter, we propose to first present these approaches to the notion of spatial baseline, and in particular, the criteria used for the selection of such sites. Second, we will illustrate these approaches with detailed examples of definitions of single or multiple baseline sites. Finally, the limits and interests of these approaches will be discussed1.
2.3. What is a spatial baseline?
The notion of spatial baseline is based on a (seemingly) simple principle: to identify, elsewhere, a site (or sites) with characteristics considered desirable. These characteristics can then be used either to establish the degradation level of the site studied, by comparison, or to define management or restoration objectives. However, the selection of these baseline sites is a complex process that can be implemented in many ways and is not easily freed from cultural and emotional characteristics; this was indeed identified by George Perkins Marsh as early as 1856; this pioneer of conservationist thinking and restoration then remarked that the regions of southern Europe lack “any thing which corresponds with an American’s idea of a forest” (Hall 2005, p. 18).
2.3.1. In search of naturalness…
It seems that the first criterion of importance for authors seeking baseline sites through a spatial approach is that of naturalness: the less a site has been subjected to pressure from human activities, the more the ecological conditions encountered there will be considered as a baseline. In the vast majority of studies, the justification for site selection is based on an argument relating to the low level of pressure and/or transformation and, in some cases (e.g., Herlihy et al. 2008; Shinneman et al. 2008), this is even the only criterion explicitly presented. There are, however, several ways to consider this naturalness. For example, the baseline conditions correspond to the attributes that a site would have if it had not been transformed by human activities, transformations being considered as degradations. In this logic, a site where pressure is non-existent corresponds to a good state of conservation, good integrity, and therefore necessarily, to good functioning (Armanini et al.
