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\DOI{10.5802/crgeos.267}
\datereceived{2022-12-29}
\daterevised{2023-12-13}
\datererevised{2024-05-06}
\dateaccepted{2024-06-06}
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%\makeatletter
%\def\TITREspecial{\relax}
%\def\cdr@specialtitle@english{Human Environment Observatory}
%\def\cdr@specialtitle@french{Observatoire Homme Milieu (OHM)}
%\makeatother

\CDRsetmeta{articletype}{research-article}

\title{The socio-ecological complexity of facing climate~change: a case
study from Pima~County~(Arizona, USA)}

\alttitle{La complexit\'{e} socio-\'{e}cologique du changement
climatique : Une \'{e}tude de cas du comt\'{e} de Pima (Arizona,
\'{E}tats-Unis)}

\author{\firstname{Fran\c{c}ois-Michel} \lastname{Le Tourneau}\CDRorcid{0000-0003-1184-8624}\IsCorresp}
\address{CNRS, UMR 8586 PRODIG, Aubervilliers, France}
\email[F.-M. Le Tourneau]{Francois-michel.le-tourneau@cnrs.fr}

\author{\firstname{Larry A.} \lastname{Fisher}}
\address{Environmental Policy, University of Arizona, Tucson, AZ, USA}

\author{\firstname{Adriana A.} \lastname{Zuniga-Teran}\CDRorcid{0000-0003-2912-2469}}
\address{School of Geography, Development and the Environment, University of Arizona, Tucson, AZ, USA}

\author{\firstname{Benjamin T.} \lastname{Wilder}}
\address{Next Generation Sonoran Desert Researchers, Tucson, AZ, USA}

\author{\firstname{Anne-Lise} \lastname{Boyer}\CDRorcid{0000-0001-8091-2015}}
\address{Labex DRIIHM, France}

\author{\firstname{David} \lastname{Blanchon}}
\address{Universit\'e Paris Nanterre et  CNRS Mosa\"{\i}ques/LAVUE, France}

\author{\firstname{Fabrice} \lastname{Dubertret}}
\address{CNRS UMR PASSAGES, Bordeaux, France}

\shortrunauthors

\keywords{\kwd{Complexity}
\kwd{Climate change} 
\kwd{Arizona} 
\kwd{Human-Environment observatories} 
\kwd{Fire}}

\altkeywords{\kwd{Complexit\'{e}}
\kwd{Changement climatique} 
\kwd{Arizona} 
\kwd{Observatoires hommes-milieux} 
\kwd{Incendie}}

\begin{abstract} 
Socio-ecological systems are in constant transformation and adaptation,
with dynamic and constant interaction between the social and
environmental dimensions. This reality requires interdisciplinary
studies, or a holistic approach sometimes referred to as ``global
ecology'', to address that complexity at every level in their analysis.
``Human-environment observatories'' (Observatoires Hommes-Milieux, OHM)
are an ideal setting to develop such studies since they are inherently
interdisciplinary and develop both short and long-term perspectives on
specific socio-ecological systems. Pima County observatory (OHMi-PC),
located in Arizona (USA), is one of the 13 ``Human-Environment
observatories'' of the DRIIHM LabEx. In this paper, we show how we can
apply the DRIIHM framework to Pima County and how this allows for
innovative interdisciplinary approaches of issues related to
environmental and human dynamics in southeastern Arizona, such as the
dynamics of wildfires, which we show to be related to human as well as
environmental factors, the restauration of the Santa Cruz river, which
we analyze as ambiguous in terms of ecology, or the Cienega creek area,
where the OHMi-PC has been involved in local landscape conservation
efforts. 
\end{abstract}

\begin{altabstract} 
Les syst\`{e}mes socio-\'{e}cologiques sont en constante transformation
et adaptation, avec une interaction dynamique et constante entre les
dimensions sociales et environnementales. Cette r\'{e}alit\'{e} exige
des \'{e}tudes interdisciplinaires, ou une approche holistique parfois
appel\'{e}e \og \'{e}cologie globale\fg{},
pour aborder cette complexit\'{e} \`{a} tous les niveaux de leur
analyse.  Les \og Observatoires
Hommes-Milieux\fg{} (OHM) constituent un cadre id\'{e}al
pour d\'{e}velopper de telles \'{e}tudes car ils sont
intrins\`{e}quement interdisciplinaires et d\'{e}veloppent des
perspectives \`{a} court et \`{a} long terme sur des syst\`{e}mes
socio-\'{e}cologiques sp\'{e}cifiques. L'observatoire du comt\'{e} de
Pima (OHMi-PC), situ\'{e} en Arizona (\'{E}tats-Unis), est l'un des 
13 \og observatoires
Homme-Environnement\fg{} du LabEx DRIIHM. Dans cet
article, nous montrons comment nous pouvons appliquer le cadre DRIIHM
au comt\'{e} de Pima et comment cela permet des approches
interdisciplinaires innovantes des questions li\'{e}es \`{a} la
dynamique environnementale et humaine dans le sud-est de l'Arizona,
telles que la dynamique des incendies de for\^{e}t, dont nous montrons
qu'elle est li\'{e}e \`{a} des facteurs humains et environnementaux, la
restauration de la rivi\`{e}re Santa Cruz, que nous analysons comme
ambigu\"{e} en termes d'\'{e}cologie, ou la zone du ruisseau Cienega,
o\`{u} l'OHMi-PC a \'{e}t\'{e} impliqu\'{e} dans les efforts de
conservation du paysage local.
\end{altabstract}

\maketitle

\vspace*{1pc}

\twocolumngrid
\end{noXML}


\xsection{}
Climate change is often described as a change in the environment that
societies must cope with, \mbox{either} by mitigation or adaptation
\citep{IPCC2022}. It has been well documented that the effects of
climate change are intertwined with those of previous environmental
practices, potentializing some of their effects and relativizing
others, and that the \mbox{pressure/response} dynamics involve numerous
feedback loops and responses between socio-economic adaptations and
local ecosystems. In fact, as several authors have claimed
\citep{BerkesFolke1998,Berkesetal2003,Chenorkian2017}, it is no
longer possible to differentiate between the ``human'' and the
``natural'' dimensions in environmental approaches, and it is therefore
necessary to consider ``socio-ecological systems'' (SES) or ``coupled
human and natural systems'' (CHANS), as proposed by 
\citet{Liuetal2007a,Liuetal2007b}. For some authors, in highly
anthropized environments, the human factor can no longer be seen as a
dimension outside the ecosystem but should be reframed as an inherent
component of what is therefore a ``single ecosystem''
\citep{Chenorkian2020}. This interrelation requires interdisciplinary
studies, or a holistic approach sometimes referred to as ``global
ecology'', not in the sense of globalization but as an approach that
considers all dimensions of a given SES ({ibid.}). 

Human-environment observatories (OHM)
\citep{Chenorkian2014,Chenorkian2020} are frameworks designed to
develop such analyses and advance with the understanding of this
complexity \citep{Liuetal2007a}, since they are inherently
interdisciplinary, and they allow a long-term perspective on specific
socio-ecological systems. Human-environment observatories provide a
focus on contemporary events through which new 
transformations---sometimes dramatic, sometimes 
subtle---are taking place. They are
excellent places to examine how environmental changes are taking shape,
but also how societies respond to this\break change. 

The ``Pima County human-environment observatory'' (OHMi-PC) is one of
the 13 ``Human-Environment observatories'' of the LaBeX
DRIIHM\footnote{DRIIHM stands for Device for Interdisciplinary Research
on human-environments Interaction (\textit{Dispositif de Recherche
Interdisciplinaire sur les Interactions Hommes-Milieux}). The DRIIHM is
a research program coordinated by the French National Center for
Scientific Research (CNRS) which is financed by the French Research
Agency (ANR) under the ``Investissements d'Avenir'' program  
(grant no.~ANR-11-LABX-0010).}.
Created in 2015, it is located in a region of
extreme climatic conditions where a very large palette of ecosystems
exists, from the semi-arid Sonoran Desert and grasslands to conifer
forests at higher elevations (Figure~\ref{fig1}).
OHMi-PC was created when an important
social conflict arose in response to a new mining project that was to
be opened in the Santa Rita mountains. But this conflict is only the
visible part of demographic and sociological changes which started in
the 1970s and triggered transformations, which are now reconfiguring
the local SES. Previously a strong proponent of resource extraction
activities that often overshadowed a nascent conservation ethic, Pima
County is becoming a place where ecosystems and landscapes are now
valued for broader and longer-term goals. As with any societal change,
however, the transformation is not an abrupt rupture but a long-going
process, and many features of the resource-extractive system are still
in place, prompting conflicts and revealing complex feedback and
retroaction loops.

\begin{figure*}
\includegraphics{fig01}
\vspace*{-5pt}
\caption{\label{fig1}The gradient of ecosystems along elevation
\citep[modified from][figure by Maya Stahl]{Wilderetal2021,Wilderetal2024}.}
\vspace*{-5pt}
\end{figure*}

This paper aims to show how the OHMi-PC is instrumental in unveiling
the complexity of SES facing climate change. To do so, we will first
discuss the socio-ecological setting in Pima County and the crises it
has faced in the last decades. We will then formulate the theoretical
framework of the ``Pima County observatory'', based on the general
DRIIHM trilateral approach and the SES framework. We will then
demonstrate how the results of three research programs nested within
the Pima County observatory exemplify the analyses of complexity in the
face of climate change, and how Pima County can be viewed as both an
observatory and a sentinel (in the sense of ``sentinel territories''
developed in  \citet{Blanchonetal2020} of climate change and climate
change adaptation.
\vspace*{-6pt}

\section{Pima County: environmental extremes and crises}\label{sec1}
\vspace*{-3pt}

Located in Southeastern Arizona, Pima County is characterized by
variable climatic conditions, high endemic biodiversity, and rapid
urbanization. The region's history and development are described by a
wealth of ecological and social studies, going back to the early days
of Native and European settlement \citep{Sheridan2012}. In this
section, we show how three major socio-ecological crises that have
occurred within the last decades---the 1980s water crisis, the 1990s
landscape crisis and the 2010s mining crisis---reflected and prompted
changes in the historical socio-ecological setting.
\vspace*{-6pt}

\subsection{The socio-ecological framework}
\vspace*{-3pt}

Southeastern Arizona is characterized by a semiarid climate. Rainfall
is about 300 mm each year with at least 3 months with less than 5 mm of
precipitation. Average annual temperature is above 20~\textdegree C.
Consequently, water is a scare and precious resource, and from the
pre-Columbian times to today, human presence has depended on some form
of water management. The presence of high-elevation areas typical of
the ``basin and range'' landscape of the western United States, allows
for high biodiversity. Mountain ranges, with peaks up to 2800 m, are
called ``sky islands'' because they appear as green forested islands in
the middle of a sea of desert grasslands and shrublands
\citep{Cristetal2014}. \citet{WhittakerNiering1965,BruscaandMoore2013} 
distinguish seven different ecosystems stacked in elevation
(Figure~\ref{fig2}), each one blending into another in delicate
transitions.\looseness=-1  

While ecological transitions appear to be delicate, contrasts are sharp
between elevation extremes Located about 30~km as the crow flies from
the center of the city of Tucson, Mount Lemmon enjoys more than 750 mm
of rainfall each year (including more than 35~cm of snow), and the
average temperature is 10\textdegree~cooler than in the Tucson basin,
yielding environmental conditions similar to those encountered 2000~km
further north, at the US-Canada border.

Climate change is having impacts on the region, yielding more intense
drought periods and an increase in mean temperatures, during both
winter and summer. Among other ecological changes, the movement of
species to higher elevations with more favorable conditions can be
noted. One conspicuous example is that of mesquite trees
(\textit{Prosopis spp.}), typical of the Sonoran Desert scrub
ecosystem, which now invade the grasslands throughout the region
\citep{Mcnewetal2023}. Recurring forest fires have been part of the
environment of the forests of the US Southwest for at least several
centuries \citep{Iniguezetal2008,Iniguezetal2016}, 
but have increased in recent
years due to drying conditions and historic management practices that
have led to a buildup of\break fuels. 

Pima County's region has been inhabited for over 10,000 years.
Indigenous civilizations have taken advantage of the few perennial
streams to develop an irrigated agriculture as early as 1500 BCE
\citep{Logan2002}. Although Spanish explorers made early reconnaissance
visits to the area in the sixteenth century, it was only during the
eighteenth century that the first settlements were established by
European colonists. However, due to its harsh climate, its remoteness
from the rest of the Spanish Empire, and regular Apache raids,
Southeastern Arizona attracted only limited interest from the Spaniards
and from the Mexicans after them.

After the US purchased the territory from Mexico in 1854\footnote{Most
of the Western part of the United States was obtained from Mexico after
the US-Mexican war of 1848 and the treaty of Guadalupe Hidalgo.
However, the territory surrendered by Mexico included only the northern
portion of the Gila river. The portion south of the river that is
currently part of Arizona and New Mexico was purchased from Mexico in
1853 by the US in order to create an easier path for a transcontinental
railroad. The acquisition is named the \textit{Gadsden Purchase} after
James Gadsden, the US ambassador in Mexico who negotiated the treaty.},
Anglo settlers poured in in greater \mbox{numbers} and started competing with
Indigenous peoples for local resources, especially water and
grasslands. ``Indian wars'', especially with the Apaches, ended in the
early 1880s with the defeat of the last bands still contesting the US
domination. From this moment on, the Indigenous populations were
confined to reserves of limited size compared to their original
territories and have undergone waves of colonial erasure up to the
present. The Anglo settlers developed an economy based on irrigated
agriculture, causing a rapid fall of the groundwater table, and
ranching (cattle and sheep), resulting in serious soil erosion. A
series of droughts at the beginning of the 20{th} century exacerbated
soil erosion to the point that the federal government passed
regulations about the use of public lands. Most of these restrictions
are still in place today or were made even more strict over time. The
exploitation of public lands is still important in Arizona, where they
represent an important share of the state  \citep{LeTourneau2019}.
Today, only 14\% of Pima County is designated as private land; 34\% is
public land and 42\% is designated for Indian reservations
(Figure~\ref{fig2}, which shows the area observed by OHMi-PC). All
remaining ranches use a mix of private and public lands for their
operations.

\begin{figure*}
\includegraphics{fig02}
\caption{\label{fig2}The part of the Santa Cruz river basin observed by
the OHMi-PC (white dotted contour) or ``focal object'' (see
Section~\ref{sec2}).}
\end{figure*}

In addition to ranching and irrigation, mining has been a crucial
aspect of the economy since the beginning of the 20{th} century.
Although gold and silver were found in Pima county's mountains, it is
copper that assumed the greatest significance. In the 1920s, industrial
open-pit mines began operations, and three of them still operate today:
Sierrita Mine and Mission Mine near Green Valley (Figure~\ref{fig3})
and Silverbell Mine, located West of Tucson. Mining, past or present,
is still a prominent feature of the local landscape.   


\begin{figure*}
{\vspace*{-2pt}}
\includegraphics{fig03}
{\vspace*{-2pt}}
\caption{\label{fig3}The imprint of mining on Pima County's
landscape: Sierrita and Mission mine, 20~km South of Tucson
(source of image: Google Earth).}
{\vspace*{-2pt}}
\end{figure*}

From the 1950s, Pima County's economy grew steadily with the expansion
of air-defense industries, the importance of Davis-Monthan Airbase and
the rise of the University of Arizona. The City of Tucson and Pima
County have seen steep population increases, and, in consequence, an
increase in the urbanized area, largely a result of the attraction of
the US middle class to sunny and dry climates, now more easily
enjoyable with the popularization of air conditioning and swimming
pools. The area covered by urban and suburban developments doubled from
1985 to 2020 [from 602~km$^{2}$ to 1316~km$^{2}$, see 
\citealp{Dubertretetal2022}, Figure~\ref{fig4}], while the population
reached 265,000 inhabitants in 1960, 531,000 in 1980, 843,000 in 2000
and more than 1 million in 2020. This increase in population favored
low-density suburban development and sprawling cities, which has had
profound impacts on the landscape and natural resources\footnote{As per
the above figures, the developed area of Pima county covers 1316
km$^{2}$ for 1.04 million persons (including downtown denser area and
suburban development), which yields an average density of 793
person/km$^{2}$, compared with an average suburban only density of 1050
in the US and 2400 in Western Europe (source Demographia.com urban
atlas).}. Water consumption also rose dramatically, resulting in more
pumping and further decline of the water table 
\citep{Poupeauetal2016,LeTourneauandDubertret2019}. This decline peaked
in the second half of the 20{th} century, when land subsidence episodes
occurred  \citep{Zuniga-TeranStaddon2019}. Since then, the region's
main water utility, Tucson Water, has implemented multiple \mbox{policies} to
manage water demand. The result has been a decrease in \textit{per
capita} as well as overall water use 
\citep{Zuniga-TeranTortajada2021}, which, however, remains much higher
than in most comparable 
{\unskip\break}areas\footnote{\citet{LeTourneauandDubertret2019} note
that domestic water consumption per capita in Arizona is double than
the French average, which is somehow surprising given that water is
much less abundant in Arizona than in France. The excess in water use
in Arizona is mainly explained by landscape irrigation.}.

\begin{figure*}
\includegraphics{fig04}
\caption{\label{fig4}Urban extension in the upper Santa Cruz watershed
from 1986 to 2020 \citep[adapted from][]{Dubertretetal2022}.}
\end{figure*}

From mining to urbanization, Pima County's socio-ecological framework
has been based on the exploitation of natural resources---grasslands
transformed into grazing areas for cattle, mining deposits explored
(first on a small scale and then industrially), water use for irrigated
agriculture and then for urban uses and finally natural landscape, with
the development of extensive low-density areas (\textit{urban sprawl}).
These developments have continued through the 1980s, until a succession
of crises made this attitude no longer sustainable. 

\subsection{From water to mining: socio-ecological crises in Pima
County}

\subsubsection{The 1980s water crisis}

At the end of the 1970s, the adverse consequences of groundwater
pumping became increasingly \unskip\break {apparent} in Central and Southeastern
Arizona. Poised to diversify its water portfolio and under pressure
from the Federal government, which insisted on the adoption of improved
water management as a precursor for financing the Central Arizona
Project (CAP)\footnote{The CAP is an extensive network of canals and
dams which carries the water from the Colorado river to southeastern
Arizona, including the city of Tucson.}, the state of Arizona adopted
in 1980, the \textit{Groundwater Management Act}
\citep{Poupeauetal2016,Engeletal2020}. The Act tied the expansion of
urban areas to the availability of renewable water  supplies and
limited the expansion of irrigated \mbox{agriculture} within six Active
Management Areas (AMAs)\footnote{Originally five, and a sixth created
in 2022.} and three Irrigated Non-expansion Areas (INAs) 
\citep{Zuniga-TeranTortajada2021}. However, these areas cover only a
fraction of the southern part of the state, leaving the rest of rural
Arizona still exposed to over-pumping.

This water crisis and the legislative framework adopted to resolve it
is considered as turning points in the history of Arizona, even if, to
a certain degree, it can be debated whether the changes were real or
merely band-aid solutions 
\citep{EuzenMorehouse2014,CortinasMunozPoupeau2019,Engeletal2020}. 
Nevertheless, it
clearly signaled the entry into a new era in which water scarcity was
acknowledged, reducing decades of groundwater overexploitation and
contributing to the redefinition of the socio-ecological framework.
Forty years after this initial Act was passed and facing the growing
impacts of climate change on the Colorado River, new measures were
undertaken through the \textit{Drought Contingency Plan (DCP)} which
increased the pressure on farmers to reduce their water use in exchange
for significant monetary compensation. 

In urban areas, the consequences of the 1980 water crisis were also
significant, with the adoption of new landscaping practices (enforcing
the reduction of lawns and other water-thirsty practices), as well as
campaigns to reduce the use of water or to promote the use of reclaimed
water\footnote{Which now constitutes about 10\% of
the water delivered by Tucson Water, see  \citet{Neeletal2020}.} for
landscape irrigation. In consequence, the average water consumption by
inhabitants has diminished since the 1970s
\citep{Benites-Gambirazioetal2016}. In 2015, after decades of
\mbox{implementing} multiple water policies, Tucson residents used 31\% less
water \textit{per capita} than they did in 1989 
\citep[2]{Zuniga-TeranTortajada2021}. 

Using surface water from the Colorado River via the CAP or through the
acquisition of water rights from agricultural farms, Tucson
metropolitan area has been able to recharge its local aquifers, and it
is currently using them to ``bank'' or store water for future use 
\citep{Zuniga-TeranStaddon2019}. However, at the scale of the county,
declining water levels and intense pumping are still the rule 
\citep{LeTourneauandDubertret2019}. Also, the CAP and water banking policies
increases the complexity of the \mbox{socio-ecosystem,} because they link
conditions in Pima county to the effects of climate change in the much
larger Colorado Basin and because they add another temporal dimension
related to the possible use of this ``stored'' water. Also, the system
is based on the idea that water stored in a given place is available
everywhere in the basin, which is an oversimplification of the
configuration of the aquifer and of aquifer flows.\looseness=-1

\subsubsection{Landscape crisis in the 1990--2000s}

The water crisis has not slowed urban growth in Pima County
(Figure~\ref{fig6}). In the mid-1990s, the progressive erosion of the
natural habitat and the \mbox{traditional} landscapes around Tucson became
apparent with the declaration of the cactus ferruginous pygmy owl
(\textit{Glaucidium brasilianum}) as an endangered species. The owl is
dependent on saguaro cacti, which are an iconic species of the Sonoran
Desert ecosystem. Under the recommendation of federal authorities,
local government agencies and a broad coalition of citizens' groups
drafted the Sonoran Desert Conservation Plan (SDCP), adopted in 1998,
and the Multi-Species Habitat Conservation Plan (MSHCP), completed in
2016 to preserve habitats, create a conservation land system, and seek
to contain urban sprawl  \citep{Zuniga-TeranStaddon2019}.\looseness=-1

The SDCP was followed by an important financial commitment from Pima
County residents, as they voted both in 1997 and 2003 to approve \$204
million of bond issues, which included the purchase of more than 80,000
ha of ranches (Figure~\ref{fig3}) in order to further limit the effects
of urbanization. In doing so, the two plans, and the measures taken in
their wake, clearly showed that the community viewed landscape
transformation as an issue that could result in loss of cultural
identity and quality of life, both revealing and trying to solve a
``landscape crisis''. The SDCP and MSHCP plans still guide urban
development policy today, but they have not halted the growth of urban
areas. Since 2010, about 2900 ha have been converted annually to urban
development  \citep{Dubertretetal2022}, indicating that the crisis may
yet continue. 

\subsubsection{Mining crisis, 2010--2020}

Until the 1970s, Pima County was, at least in part, considered as
``mining country''---a place where the exploration of
mining deposits was actively promoted. This is evidenced by the
presence and continuous operation of world-class mines and the
development of urban areas (Sahuarita and Green Valley) in their
immediate vicinity (Figure~\ref{fig4}), even though pollution and
contamination linked to this activity have been well documented 
\citep{KimHarris1996,Boyer2016}. However, the growing awareness of
environmental concerns, linked to water use and landscape change, has
compounded this aspect of the local SES and reflected in the intense
controversy surrounding the proposed development of a new copper mine
(Rosemont mine) in the Santa Rita\break mountains.

When the mine was first proposed, the project was backed by the
Republican-dominated state \mbox{government} and several local stakeholders
linked to the mining industry. However, the proposal faced resolute
opposition from a broad coalition of environmentalists, the Tohono
O'odham Nation, and other stakeholders, including ranchers and tour
operators. While many feared that their activities would be negatively
impacted by the open-pit mine, all opponents shared the perception of
the mine as an unacceptable aggression against the environment and the
region's natural history and heritage
\citep{Boyeretal2017,LeGouilletal2018}. After years of legal
battles\footnote{The most recent episode was a ruling from a federal
judge in 2019, confirmed in 2022, who determined that despite the fact
that Rosemont Copper Company had the mineral rights on its private
parcels, it could not use public land managed by the US Forest Service
for dumping mining wastes. The ruling stated that while the 1872 Mining
Act does allow for direct use (i.e., mining) on federal lands, it does
not include provisions for related activities ``in connection with
mining operations'', such as the dumping of mining waste.}, the project
design was modified to enable access through the Western side of the
Santa Rita mountains on private lands owned by the mining company. The
public battle of the Rosemont Mine, which continues today, signaled a
major change in Pima County's SES, where the appreciation (and the
perceived economic value) of natural landscapes began to outweigh the
economic gains from the extraction of natural resources. The conflict
also touches on a wide set of issues, including possible impacts on the
hydrology of Cienega Creek, one of the last perennial streams of the
region.
\vspace*{-5pt}

\section{OHMi Pima County as an observatory of the complexity in a
``single ecosystem''}\label{sec2}

OHMi-PC is based on the DRIIHM's innovative trilateral approach to the
concepts of SES and complexity in order to promote a ``global ecology
approach''.
\vspace*{-5pt}

\subsection{Socio-ecosystems and disrupting events: the DRIIHM
approach}

As \citet{Chenorkian2014,Chenorkian2017} describes, the DRIIHM
scientific framework for the human-environment observatories is based
on three fundamental elements. The first is a socio-ecological
framework that has been in place for a significant period of time and
of significant influence in the area, leading especially to important
environmental transformations. The second is a ``disrupting event'',
always of anthropic origin, which totally or significantly transforms
this setting, prompting its reorientation and adaptation. Finally, the
third element is a ``focal object'', i.e., an area where the
socio-ecological framework is deployed and on which, consequently, the
effects of the disrupting event are felt. ``Human-Environment''
observatories have been established in places where these three
features are identified. The observatories seek to document how the
perturbations related to the disrupting event are absorbed and result
either in the adaptation of the previous SES (prompting inquiries about
the resilience of such systems) or a new configuration. \looseness=-1


\subsection{The OHMi-PC defining elements}

Pima County corresponds well to the DRIIHM framework. Its environment
has been extensively influenced by humans, especially during the last
two centuries when a socio-ecological framework emerged based on the
extraction or use of natural resources. This framework, has, however,
been deeply shaken in the last decades, as evidenced by the conflict
around the Rosemont mine project. But this conflict is only the
manifestation of changes which have been building through the three
crises described in Section~\ref{sec1}. 

These changes are linked to important demographic and social
transformations in Pima County, whose population grew and became more
urban and more educated \citep{Sheridan2012}. Environmental concerns
were already deeply rooted in Tucson, where one of the first US
ecological stations (the Desert Botanical Laboratory on Tumamoc Hill
established by the Carnegie Institution in 1903) was installed and
where, as early as the 1920s and 1930s, protected areas were created 
\citep{LeTourneauandDubertret2019}. Tucson has also been home to
relatively intense activity by the Sierra Club, one of the United
States' most influential conservation organizations, and by several
other local, regional, and national non-profit environmental
groups\footnote{A short list would include the Center for Biological
Diversity, the Nature Conservancy, Defenders of Wildlife, Sky Island
Alliance, Tucson Audubon Society, Coalition for Sonoran Desert
Conservation, Arizona Land and Water Trust, Watershed Management Group,
Save the Scenic Santa Ritas, and many others.}. However, these
historical precedents did not challenge the \mbox{predominant} development
model based on intensive resource extraction until the water (and
subsequent landscape and mining) crisis exploded. A different social
positioning, until then limited to intellectuals like the well-known
writer Edward Abbey\footnote{See, \textit{inter alia}, Desert Solitaire
(1968), The Monkey Wrench Gang (1975), The Fool's Progress (1988).} and
small groups of environmentalists, started to spread more largely,
contesting the notion of urban sprawl and the priority of economic
growth. This change in attitude about the environment, which is echoed
in the three crises described above, is considered to be the OHMi-PC's
pivotal disrupting event.

The conflict around the Rosemont Mine is nevertheless viewed as a key
catalyst. For the first time, an industrial project was openly opposed
through the mobilization of civil society organizations and, even if
the mine eventually does open, its exploitation has already been
delayed for more than ten years by the large coalition of stakeholders
\citep{Boyeretal2017,LeGouilletal2018}, and its configuration has
changed dramatically. Significantly, the coalition against the mine
included formerly antagonistic forces, such as ecologists and ranchers
\citep{LacuissePoupeau2023}, which is a proof of change in the
community positioning about ecological issues. For most members of the
opposition, the environment represents an intrinsic value other than a
source of exploitable commodities. There is also a growing awareness of
the concept of environmental services, e.g.~through the development of
eco-tourism and outdoor recreational activities, or the fact that
landscape amenities are pushing the price of properties in Pima County,
making residents more eager to preserve these landscapes to protect
their investments.

Figure~\ref{fig5} describes the different elements revealing the
emergence of the OHMi-PC disrupting event, rooted in the water,
landscape and mining crises and made more evident with the conflict
around the Rosemont mine. This includes elements of adaptation that
illustrate the gradual evolution of a new SES. Overall, we can see the
acceleration of events from the 1980s and even more from the 2000s. The
``focal object'' observed by OHMi-PC correspond to a region which
overlaps most part of the upper Santa Cruz river Watershed in Pima and
Santa Cruz counties (Figure~\ref{fig2}).

\begin{figure*}
\vspace*{-4pt}
\includegraphics{fig05}
\vspace*{-6pt}
\caption{\setcounter{footnote}{0}\def\thefootnote{\alph{footnote}}
\label{fig5}A chronological representation of the elements
revealing the OHMi-PC disrupting event\protect\footnote{Each curve or
surface representation correspond to statistics collected by the
observatory. Scales were modified or adapted to match the format. The
goal of this figure is not to pinpoint values for each phenomenon but
to show the trends and global evolution of each.}.}
\vspace*{-6pt}
\end{figure*}

\begin{figure*}
\includegraphics{fig06}
\vspace*{-3pt}
\caption{\label{fig6}The newly released stream of water of the 
Santa Cruz River in Tucson (2019).}
\vspace*{-3pt}
\end{figure*}

\subsection{Complexity and interdisciplinarity at the core of the
OHMi-PC action}

Human influence on ecosystems has dramatically increased in the 21st
century, both in terms of the area it affects directly and in the
intensity of its influence, a phenomenon sometimes referred to as the
``great acceleration'' \citep{McNeillandEngelke2016}. In \mbox{consequence},
contemporary studies tend to point out that nature-related and
human-related factors are now fundamentally intertwined. Therefore,
what is to be studied are coupled human and natural system (or CHANS,
see \citet{Liuetal2007a,Liuetal2007b}, or even a single
socio-ecological system \citep{Berkesetal2003,Chenorkian2020}. 

This requires the breaking of disciplinary boundaries or at least
significant inter-disciplinary collaboration, since sociology or
political ecology help explain biological and ecological
transformations. As \cite{Liuetal2007a} show, approaching SES or CHANS
exposes complexity since the interactions that must be described are
multidimensional and span multiple spatial and temporal scales, an
approach to \mbox{environmental} studies referred to as ``global ecology''
\citep{Chenorkian2020}. As we showcase in Section~\ref{sec3},
Human-Environment
observatories in general, and the OHMi-PC in particular, are ideal
places to analyze this complexity, since their foundational concepts
are interdisciplinary and combine environmental science, ecology,
biology and social sciences. Examples of how this interdisciplinary
approach within OHMi-PC will be developed in Section~\ref{sec3}.\looseness=-1 

As underscored by \citet{Chenorkian2014,Chenorkian2017}, the
Human-Environment observatories do not function merely as research
programs where pre-defined goals are to be attained and where tasks are
set up in advance.~They are more accurately described as melting pots,
where all disciplines and interests are blended to produce innovative
science. From a conceptual point of view, the observatory dynamics are
bottom-up as well as top-down, fostering the emergence of new projects
within the established framework. The OHMi-PC, as well as the DRIIHM
project in general, thus tend to act as ecosystems, staging
interactions, retroactions and emergences within their components.

\section{From wildfires to water to action: revealing the complexity of
human-environment interactions}\label{sec3}

In this part, we will turn to three examples of research supported by
OHMi-PC to showcase its \mbox{interdisciplinary} approach based on the
disrupting event identified in Section~\ref{sec2} and explore different aspects of
its consequences. There is a progression among these examples. The
first, about wildfires, takes what is often viewed as a purely natural
phenomenon to show how it is very much influenced by human activity;
the second, of the Santa Cruz ecological restoration projects,
highlights legacy effects and time lags; the third, about action
research in the Cienega Watershed, demonstrates the challenges of
engaging in complex analysis while providing useful guidance for
collective action. 

\subsection{(Wild?)fires in the Sonoran Desert: the interplay between
climate change and past \mbox{policies}}

Fire regimes in Southeastern Arizona are a good example of the complex
relationship between human activities and environmental change. As
mentioned in Section~\ref{sec1}, fires have 
been part of the ecosystem and their
history has been well-documented \citep{Iniguezetal2008,Iniguezetal2016}.
This  long-term history changed dramatically during the 20{th} century
with the United States Department of Agriculture (USDA) Forest
Service's adoption of fire suppression policies. Nevertheless, large
wildfires occurred during the early 2000s including the Bullock Fire
(2002, 124~km$^2$), the Aspen Fire (2003, 344~km$^2$) and, more
recently, the Bighorn Fire (2020, 486~km$^2$). 

The reappearance of fires is due to a complex web of natural and
human-induced causes. On the one hand, climate change and global
warming create more prolonged and intense droughts which make
high-elevation forests more vulnerable to fire events. Such changes
impact the composition of the forests, with post-fire communities often
shifting to novel states \citep{OConnoretal2020}. But the preoccupation
with fires also underlines the ``landscape crisis'' part of the OHMi-PC
disrupting event since urban encroachment has put a greater segment of
the population at risk.

This vulnerability also stems from the policies and practices that were
adopted to protect the forests from fire. With the allocation of public
forests for grazing and timber harvesting---as part of the
extraction of natural resources bases framework from the
19{th} century, fire was viewed as a threat to economic
activities, and therefore something to be eliminated. Fire brigades and
monitoring devices (such as look out towers, now mostly deactivated but
still dotting most peaks) and management practices like the opening of
roads and trails allowing fire teams to access remote areas and served
to drastically reduce wildfires for almost a century. But such success
unwittingly paved the way for an aggravated problem. In the absence of
regular fire regimes, forested areas began to store a much greater
quantity of fuel, especially in the form of dry wood, resulting in
longer, hotter, and more intense wildfires and increased tree mortality
(and dead trees provide even more fuel for subsequent fires). After
many decades of fire suppression communities and institutions favored
investments in stronger fire suppression measures (improved monitoring,
reinforced fire brigades, new equipment) rather than in policies that
allow coexisting with wildfires, such as the use of controlled burns,
frequently cited as a better way of avoiding catastrophic events.
Another consequence of the efficiency of fire suppression is that
communities expanded settlements closer to forest areas, putting them
at higher risk and further reinforcing the emphasis on suppression
measures.

Following the Bighorn Fire of 2020, studies partially funded by OHMi-PC
showed that changes in the fire regime were not restricted to the
forest or grassland ecosystems of the Sky Islands, but that they now
also impacted the Sonoran Desert, long considered as inherently
fireproof  \citep{Wilderetal2021,Wilderetal2024}. Invasive species spreading inside
the Sonoran Desert ecosystem and competing with endemic species
\citep{Betancourt2015}, is in large part driving this story, especially
Buffelgrass (\textit{Cenchrus ciliaris}), a perennial grass introduced
from Africa. First imported and planted to improve pasture in the
Mexican part of the Sonoran Desert, it was also used by American
ranchers since the 1930s to prevent erosion. Well adapted to aridity,
Buffelgrass started to spread, creating thick continuous patches of
vegetation and preventing other plants from growing. The continuous
carpet of Buffelgrass creates a previously non-existing connectivity of
flammable material, meaning that ``\textit{wildfires driven by invasive
grasses can spread from the desert valleys to the forested mountains,
and vice versa}''  \citep{Wilderetal2021,Wilderetal2024}. Dried Buffelgrass also
provides fuel that increases fire temperatures and damages other iconic
plants such as the Saguaro cactus (\textit{Carnegia gigantea}).

In the desert habitats, wetter years paradoxically create more fires.
During wetter years, grassland vegetation experiences greater growth
than usual, and, after drying out during the summer, it creates a thick
layer of easily flammable grasses that can rapidly spread fire from one
area to another. Simulations run in  \citet{Wilderetal2021,Wilderetal2024} confirm the
anticipated growing impact of Buffelgrass in the coming decades; other
studies have noted the lack of success of policies aimed at limiting
its spread \citep{BrennerFranklin2017,Lienetal2021}, particularly on
the Mexican side of the border, where ranchers still intentionally
plant it.

The issue of wildfires is emblematic of the complexity of SES and the
need for interdisciplinary approaches. Fire cannot be understood
through a simple analysis where global warming is the main driver of
increased fire vulnerability, since human activities and policies have
been instrumental in shaping the current situation. Human adaptations
and natural phenomena all link into a complex chain of feedbacks and
interactions, to the point where it is no longer possible to
distinguish between the two dimensions. 

Finally, one side of the OHMi-PC ``disrupting event'' is the greater
popularity of environment-related activities like hiking, camping, and
bird watching, which relations with fire are not one-sided. Increased
use of forest areas can boost the risk of human-triggered fires in the
summer, but \citet{Wilderetal2021,Wilderetal2024} also observe that small
trails in the Sonoran Desert create enough discontinuity in the
vegetation to work as fire breaks, a point which should be taken into
account.   

\subsection{Making the Santa Cruz flow again: the ambiguities of
``ecological restorations''}

As pointed out in Section~\ref{sec1}, the area covered by the OHMi-PC
has been marked by a water crisis that became apparent in the 1970s.
Irrigated agriculture, mining and urban growth have all depended on
large-scale pumping, resulting in a steep decline in the water table,
which fell by 200 feet from 1952 to 1990 
\citep{LeTourneauandDubertret2019}, and in the drying out of formerly
perennial streams such as the Santa Cruz River
\citep{LeeWoodetal1999,Webbetal2014}. Water in the Santa Cruz River
flows now only a few days each year
\citep{Logan2002,Webbetal2014,Serrat-Capdevila2016}. The riverbed was
relegated to marginalized populations and often used as an informal
waste dump, or a ``wasted space''  \citep{CarreandLeTourneau2016}.  

If the river was almost erased, its symbolical value remained strong,
especially in Arizona where water symbolizes abundance and life. As
early as the 1950s, the Nogales International Wastewater Treatment
Plant (located in Rio Rico, Arizona) and the Agua Nueva Water
Reclamation Facility (in Tucson) released effluent into the riverbed,
but these releases were more a source of nuisance (bad smell, bad water
quality) than a demonstration of restoration. After 2009, upgrades to
the water treatment installations removed the nuisance associated with
insufficiently treated wastewater, allowing the rebirth of a
functioning river ecosystem, epitomized by the reemergence of an
endangered species, the Gila Topminnow (\textit{Poeciliopsis
occidentalis}).

\setcounter{footnote}{10}

At the end of the decade of 2010, the city of Tucson and its water
management agency (Tucson Water) sponsored the development of the Santa
Cruz River Heritage Project, which allocates a portion of the reclaimed
water that was formerly released downstream from the city center to be
released upstream. This creates a flow of water through the downtown
area, where people can see and experience a ``running river''
(Figure~\ref{fig6}). While modest, this stream quickly modified the
riverbed through the growth of riparian vegetation and the emergence of
an aquatic ecosystem\footnote{An additional benefit is that since 2019,
water released into riverbeds is given a 95\% equivalent credit in the
water banking system managed by Arizona. While the water released
downstream mainly benefits other areas, those released by the Heritage
project directly benefit the city of Tucson in this respect.}.
Anticipating this transformation, the project also worked to revitalize
existing trails for recreation and tourism and to boost economic
development of a new ``waterfront''. After decades of turning its back
on this disappearing river, the city was now trying to restore and
embrace it. 

These initiatives are manifestations of the OHMi disrupting event,
signaling both the acuteness of the water crisis and a new approach to
natural resources, aimed at preserving and restoring the environment
instead of using it relentlessly. Nevertheless, they also show some
limits of this change. As the literature on this topic shows
\citep{Higgs1997,DufourPiegay2009,Morandietal2021},
ecological restoration aims at recreating functioning ecosystems. In
these specific cases, as the water table has not been restored overall,
the flow in the riverbed is dependent on the effluents of treatment
plants and would vanish without water release. The system that has been
(re)created is therefore artificial, even if it now sustains some
ecological processes. The amount of water released is dependent upon
the immediate consumption of urban areas, which tends to peak in the
morning and late afternoon, and to diminish during the 
nighttime---a sequence that depends exclusively on social cycles.

How much water is available in the long run also depends on
geopolitical and local political factors \citep{Neeletal2020}.
Regarding the first, the Nogales wastewater treatment plant, sited
downstream from Nogales on the US side, processes the water from both
the American and the Mexican cities of Nogales. The only reason it
releases part of the flow is that it is legally owned by Mexico and
therefore not available for other uses by the US. But should Mexico
decide to build its own plant and treat wastewater currently sent to
the US, the volume currently released in the Santa Cruz riverbed in the
US could diminish by as much as 80\%, which would likely reduce the
length of the flow (currently about 20~km) by the same proportion 
\citep{Zuniga-Teranetal2021}. Regarding the second factor, Pima County
and the City of Tucson have promoted the use of reclaimed water to
irrigate golf courses or lawns, but in doing so they are creating
competition for reclaimed water. The more that is spent for such uses,
the less that will be available to be freely released into the
riverbed. In addition, water conservation practices (e.g., using
graywater for landscape irrigation, adopting low-volume toilets and
water fixtures), if massively adopted, may reduce the volume of
wastewater, and consequently, reclaimed water. Paradoxically,
therefore, a more virtuous use of water and reclaimed water would
probably be detrimental to the ``restoration'' of the Santa Cruz River.

Finally, the Santa Cruz River Heritage Project shows how the legacy of
previous policies and behaviors can impact new projects. The release of
water upstream from the city's downtown area substantially raised the
local water table, which should have been a positive development. But
the project also has to deal with an area near the riverbed had
previously been used as a landfill potentially contaminated by
hazardous waste. As the rise of the water table could lead to the
leaching of toxic elements, authorities decided in 2020 to reduce the
volume of water to be released by more than half, thereby limiting the
ecological potential of the ``restoration'' process. 

Climate change, finally, also modifies the management conditions for
the project, by creating a greater number of extreme events like
prolonged droughts or intense rainfall. The Santa Cruz River now
functions more like a wash (a water-carved gully or channel),
characterized by violent flash floods potentially catastrophic to human
infrastructure. Consequently, rivers that run through urban areas raise
safety concerns for flooding that have prompted the construction of
walls along the main channel and the regular removal of sediment from
the riverbed \citep{Varadyetal2021}. Also, violent floods have the
potential to convey the finer sediments of the riverbed
away\footnote{This happened during the summer 2021
monsoon when more intense rainfalls than usual were recorded.}, leaving
it more permeable to the water. In this context, the water table will
rise more easily, which will probably call again for a diminution of
the volume released by the Heritage project. The restoration of the
Santa Cruz River in this stretch is towards that of a marsh, rather
than a riparian forest. As we see here, there are complex feedback and
retroaction loops between ecological processes, climate change, and
policies intended to remedy previous environmental damages. Approaching
these issues requires an interdisciplinary approach from geomorphology
and sedimentology to climatology and sociology, which is central to the
OHMi-PC and the DRIIHM\break framework. 

\subsection{Putting research into action: the cienega watershed
partnership}

Located southeast of Tucson in a region of grassland and woodland above
1200 m in elevation, Cienega Creek is the last remaining perennial (but
intermittent) stream in Pima County. The Creek runs through a watershed
spanning about 120,000 ha composed principally of public lands (State
and Federal) and private properties, some of which have been placed
under conservation easements (Figure~\ref{fig7}). The federal Bureau of
Land Management (BLM) established the Las Cienegas National
Conservation Area (LCNCA) in the early 2000s to protect its biological
resources while maintaining historic activities like ranching,
corresponding to the BLM's ``multiple use'' mandate. North of the LCNCA
lies a smaller protected area (Cienega Creek Natural Preserve) managed
by Pima County, with the objective of contributing to the protection of
Tucson's aquifer. Like the rest of the County the area is impacted by
climate change, invasive species, and other challenges like wildfires 
\citep{BodnerandRobles2017,Goodrichetal2020}.\looseness=1

\begin{figure*}
\includegraphics{fig07}
\caption{\label{fig7}Land use and land ownership in the Cienega Creek
Watershed \citep{Zuniga-Teranetal2022}.}
\end{figure*}

Community engagement in the Cienega Creek area started in the mid-1990s
and initially focused on the drafting of the BLM's Resource Management
Plan. At the beginning of the 2000s, the Cienega Watershed Partnership
(CWP) was created as a broad-based alliance to support the
collaborative adaptive management approach proposed by the BLM 
\citep{Zuniga-Teranetal2022}. Starting in 2008, CWP sponsored an annual
meeting, ``The State of the Cienega Watershed'', where all stakeholders
in the region meet to discuss priorities and actions. But marshaling
the different lines of actions of all partners implied the definition
of common goals, which, in turn, implied a comprehensive diagnostic of
watershed conditions. Therefore, in 2015, the idea of a common set of
indicators depicting the overall health of the watershed was adopted.
In 2017, CWP partners developed a first set of indicators, collected
all the necessary data and produced the first annual assessment. Since
2019, OHMi-PC has supported CWP and its efforts to constantly improve
this system, which offers a broader and longer-term perspective on the
watershed and challenges all participating agencies and organizations
to come to agreement over management decision making.

\begin{figure*}
\includegraphics{fig08}
\caption{\label{fig8}Indicators used to guide the action of CWP
(Source: CWP report 2021).}
\end{figure*}

Currently, the assessment uses 23 indicators grouped into four
categories---climate, water, ecological, and socio-cultural
(Figure~\ref{fig8}). The process of indicator selection reflected some of the
challenges of such an endeavor since the lead authors had to reconcile
the varied interests of partners and stakeholders. Other challenges
included limitations in data availability, the lack of continuity in
data gathering methods and measures, issues of scale, and the need to
keep the system accessible for partners with more limited technical
backgrounds. Overall, the objective is not to provide groups with
precise information about their individual interests (they already have
the relevant data), but to provide a broader, more comprehensive view
of the watershed and to improve coordination and mutual awareness of
the interplay and interdependences between all factors, natural or
human-related. For this reason, the annual State of the Watershed
assessment relies heavily on visual communication aimed at the CWP
members and the wider public\footnote{The last version of this
assessment (2021) is available on the CWP website (cienega.org):
\url{http://www.cienega.org/wp-content/uploads/2021/10/SOW_meeting_2021_long-version.pdf}.}.

Paradoxically, developing this simplified assessment system reinforced
the high degree of complexity in this system. The interpretation of
some of the indicators was not as straightforward as one might assume
\citep{Zuniga-Teranetal2022}. For instance, wildfires are part of the
natural history of the area, stimulating growth of vegetation in the
grasslands, but they can also devastate features like riparian
cottonwood groves and infrastructures. Hence, while fire was viewed as
of crucial importance in evaluating ecosystem health, interpreting fire
data as positive or negative is in the eye of the beholder. Similarly,
the number of recreation permits allows for monitoring the pressure of
recreational activities on the ecosystem, but how should these numbers
be interpreted? More permits evidently mean more pressure, but fewer
permits could also signal less interest, and therefore less public
engagement and support, for conservation goals. These discussions
underscore the inherent complexity of these phenomena, and the need to
use monitoring data to elicit varied interpretations among CWP
stakeholders. 

The ultimate value of the assessment system is to identify long-term
trends and raise the level of awareness of stakeholders about changes
that are taking place, an important foundation for both the adaptive
management and the collaborative approach that are central to effective
management of the Cienega watershed. As natural and human-related
causes of environmental change are intertwined, wider issues like water
level decline or land cover change due to invasive species encroachment
may not result in simple or immediate solutions. But, given the nature
of these challenges, collaborative action adds 
complexity---administrative and jurisdictional, staffing changes, budget
constraints, stakeholders' dynamics and fatigue. Therefore, the key
challenge is to close the loop by converting observations like those
promoted by the OHMi-PC into a catalyst for concrete action. The
pivotal role played by OHMi researchers in the definition of the
indicator system as well as the concrete actions carried out within the
OHMI-PC/CWP partnership show both the potential of the research-society
link and the ability of the DRIIHM framework to foster this discourse.
The Cienega Creek watershed is particularly interesting for the OHMi
since it combines all three aspects of the water, landscape and mining
crises, and shows the reconfiguration of the SES with its innovative
coalition constructed around the idea of preserving the \mbox{environment}.  

\section{Conclusion: from observatory to sentinel?}\label{sec4}

The OHMi-PC's ``focal object'' is a region where climate change effects
are already conspicuous because of the arid and highly variable
characteristics of its environment. As we have shown in the paper, the
DRIIHM framework and the configuration of the OHMi-PC allows for
innovative interdisciplinary approaches of different dynamics that are
taking place in this region, especially by pointing out how there are
many interactions and feedback loops between natural and human-induced
phenomena.  

As a region that is conscious of change and working continuously to
adapt, Pima County is also what \citet{Blanchonetal2020} call a
``sentinel territory'', i.e., ``\textit{spaces where early-warning
signals of environmental threats can be observed. [\ldots] sentinels can
signal them at the moment they arise and open the way to mitigating
lines of action}.'' (2019:~1). By identifying new fire regimes, by
pinpointing the limits and fragilities of restoration processes, or by
participating in the definition of the management of a protected area,
the OHMi-PC provides important contributions to this ongoing process of
raising awareness and helping stakeholders anticipate and cope with
change.  

\section*{Declaration of interests}
The authors do not work for, advise, own shares in, or receive funds
from any organization that could benefit from this article, and have
declared no affiliations other than their research organizations.

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