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LETTER
Modelling avocado-driven deforestation in Michoac´
an, Mexico
Eugenio Y Arima1,∗, Audrey Denvir1, Kenneth R Young1, Antonio Gonz´
alez-Rodríguez2
and Felipe García-Oliva2
1Department of Geography and the Environment, University of Texas at Austin, Austin, TX, United States of America
2Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Morelia, México
∗Author to whom any correspondence should be addressed.
E-mail: arima@austin.utexas.edu
Keywords: land use change, land change modelling, commodities, climate change
Supplementary material for this article is available online
Abstract
As demand for avocado climbs, avocado production in Michoac´
an—Mexico’s biggest avocado
growing region—expands into new places. We use a spatial probit model to project the geographic
distribution of likely future avocado expansion and analyze those results to determine (a) threats to
specific forest types and (b) how the distribution of avocado is shifting spatially under current and
future climate scenarios. Our results suggest that avocado expansion in Michoac´
an is strongly
driven by distance to existing agriculture, roads, and localities, as well as the dwindling availability
of Andosol soils. As future expansion ensues, it presents risk of forest loss across various forest
types, with pine-oak forest, mesophilic montane forest, and oyamel fir forest being of particular
concern. Moreover, our results suggest that avocado production will occupy wider ranges in terms
of temperature, precipitation, slope steepness and soil. The model predicts that climate change will
alter the spatial distribution of avocado plantings, expanding into forest types at lower and at
higher elevations. Forest loss threatens ecosystem degradation, and a wider avocado crop
production footprint could lead to orchard establishment into dwindling forests that host a high
diversity of native oaks and charismatic species, including the monarch butterfly.
1. Introduction
Global demand for avocado (Persea americana Mill.)
has increased dramatically in the past two decades.
Avocado exports from Mexico increased from 90 000
metric tons in 2003 to 1.3 million metric tons in 2019
(Servicio de Información Agroalimentaria y Pesquera
2019), and they are projected to continue increas-
ing (FAO 2020). To meet this demand, farmers in
regions that produce avocado are making changes in
land use to enable production expansion. Recently,
Denvir et al (2022) and Borrego and Allende (2021)
reviewed the available information on both ecological
and social dimensions of these changes, in regards
forest integrity, soil/water management, and the vari-
ous economic, labor, and equity concerns that may
arise. They identified a particular need to develop
assessment and predictive tools allowing for integ-
rated approaches to these and other socioenviron-
mental changes driven by commodities and their sup-
ply chains. This paper introduces a novel approach for
making such predictions using spatial Bayesian probit
statistical modeling.
Michoac´
an is the largest avocado producing
region in Mexico and the only Mexican state that can
export to the United States. As such, the region has
seen drastic expansion of avocado production since
the United States started allowing Mexican avocado
imports in 1997. This expansion threatens the dif-
ferent forest types that make up much of the coun-
try’s central volcanic belt region (figure 1) (Mas et al
2017, Cho et al 2021). The export restriction that
is currently in place allows us to evaluate a type
of ‘natural experiment’ wherein the export limita-
tion to produce from Michoac´
an concentrates fron-
tier expansion in a relatively limited administrative
area, at least until or if such controls are lifted.
We suggest that our approach allows not only for
policy evaluations meant to limit or mitigate socioen-
vironmental harm in Mexico but may provide a
means to examine supply chain sustainability more
generally.
© 2022 The Author(s). Published by IOP Publishing Ltd
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
Figure 1. Study area. Avocado Belt consists of 65 municipalities, 52 of which are the highest avocado producing municipalities in
the region. The area is also defined by a relatively temperate climate, higher elevation, and higher concentration of Andosols,
when compared to the rest of the state.
Although predictions of increasing avocado pro-
duction and trade have been made by agricultural
organizations like the USDA and FAO (FAO 2020,
Osoyo 2020), geographical studies of where such
expansion may occur are just beginning to emerge
(Charre-Medellin et al 2021). Here, we use a spa-
tial Bayesian probit model to build on this nas-
cent research and project the geographic distribution
of avocado expansion into natural forests. Under-
standing the spatial distribution of expansion allows
us to make a nuanced and targeted assessment of
the implications of forest conversion into avocado
plantations and a widening ecological distribution of
avocado production. These impacts pose threats to
regional ecosystems and increase risks to production
of avocado. In this article, we first introduce the study
area, provide details of the quantitative approaches,
and then discuss implications for the forests and
growers.
2. Methods
2.1. Study area
We began by delimiting Michoac´
an’s ‘Avocado Belt’
based on production and spatial contiguity (figure 1).
Of the 65 included municipalities, 52 are the top avo-
cado producing municipalities in the state, and the
13 remaining municipalities complete a contiguous
geographic region. This area contains approximately
1356 km2of avocado, 590 km2of which was planted
between 1992 and 2017 (based on INEGI agricultural
classification maps). The belt spans 18.7◦N and 20.1◦
N latitude, and 100.1◦W and 102.9◦W longitude,
and constitutes a cohesive ecological area in terms
of temperature, precipitation, biogeography, vegeta-
tion types, soil groups, and terrain. Compared to the
state as a whole, the Avocado Belt has lower aver-
age temperatures and higher precipitation. Because of
this, the area is dominated by temperate forest types,
including coniferous and oak forests, which differ-
entiates it from the rest of the state, where tropical
forests predominate. In terms of terrain, the Avocado
Belt falls within the Trans-Mexican Volcanic Belt, giv-
ing it generally higher elevations than the rest of the
state. This also impacts soils, as the highest domina-
tion of volcanic soils, mainly Andosols, in Michoac´
an
occur within the Avocado Belt.
2.2. Land change model
Expansion of new avocado into forests was modeled
in two steps, one aspatial and the other spatially expli-
cit. The aspatial component estimates the total land
area of avocado expansion projected to occur by the
year 2050 in Michoac´
an. The second component spa-
tially allocates that amount across the landscape of the
Avocado Belt.
2.3. Estimation of the amount of avocado
expansion
To estimate the amount of land that could undergo
land change for avocado expansion, data were
obtained from Mexico’s Agrifood and Fisheries
2
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
Figure 2. Projection of area of avocado land expansion in Michoac´
an. Hectares of avocado planted in Michoac´
an are shown in
black between 1980 and 2019. Four scenarios of projected avocado expansion to 2050 are shown based on (1) linear trend of area
of avocado harvested in Mexico, (2) linear trend of area of avocado harvested in Michoac´
an, (3) linear trend of area of avocado
planted in Michoac´
an, and (4) 1.5% annual growth.
Information Service (SIAP, in Spanish) on (a) area of
avocado harvested in Mexico, (b) area of avocado har-
vested in Michoac´
an, and (c) area of avocado planted
in Michoac´
an. All data range from 1980 to 2019. Lin-
ear trendlines were calculated for each dataset that
were then used to forecast the additional area of avo-
cado planted in Michoac´
an out to 2050 to create three
scenarios of avocado expansion (figure 2).
A fourth scenario was crafted from information
in the FAO report of ‘Medium-term outlook for
global production and export and trade in bananas
and Tropical Fruit’ (FAO 2020). This report’s projec-
tions about production and export growth for avo-
cado, as well as tropical fruits more generally, range
between 1% and 3% annual growth, regarding meas-
ures of land area, production output, and export
volumes. Considering these data, a fourth scenario
was calculated using a 1.5% annual growth rate for
area planted in Michoac´
an as a conservative middle-
ground between the different FAO projections.
The trends associated with the different scenarios
described above create an envelope of potential avo-
cado expansion, ranging from high to low expan-
sion rates. All models are remarkably close in their
predictions. Nonetheless, we take the ensemble aver-
age growth rate, rounded to 1000 km2, to simulate
the avocado planted area in 2050, a common prac-
tice in modeling (Gregory et al 2001, Dormann et al
2018), because it typically captures the overall trend
while attenuating some of the noise of individual
forecasts.
2.4. Spatial allocation model
To allocate where the additional deforestation asso-
ciated with future avocado expansion is most likely
to occur, we calculated the deforestation probability
based on actual deforestation attributed to avocado
plantations from the period between 1992 and 2017.
We used a spatial Bayesian probit model according
to Smith and LeSage (2004) and Arima (2016) and
included the explanatory variables in table 1. Cells
were 100 ×100 m, and the model accounted for spa-
tial autocorrelation between groups of 1 km2neigh-
boring cells. Three climate scenarios were used to
project avocado expansion into the future. Expan-
sion was predicted using present climate variables,
as well as two IPCC representative concentration
pathways for climate change—a conservative and a
worst-case scenario (RCP 2.6 and 8.5, respectively).
The details of this model are described in supple-
mentary information section 2 (available online at
stacks.iop.org/ERL/17/034015/mmedia). The model
overall performance assessment is described in the SI
document, section 5. In addition to statistical signi-
ficance, we also highlight in the Results section the
practical significance of the variables of interest by
measuring the so-called average partial effect (See SI
document, section 6).
To estimate loss of different forest types, the
model was run with 10 000 Monte Carlo simula-
tions, where the probability of change to avocado pro-
duction, assigned to each cell by the probit model,
was compared against a randomly generated num-
ber between 0 and 1 taken from a uniform distribu-
tion. Deforestation was allocated to a non-deforested
cell only if the calculated probability of conversion
to avocado was greater than the randomly generated
number. Each simulation of deforestation was then
compared to forest type layers from the 2017 INEGI
vegetation maps to calculate how much forest loss
occurred for each forest type. This method allows
an element of stochasticity and results in a distribu-
tion of 10 000 estimations of loss for each type of
forest. The same technique was applied to estimate
encroachment on protected areas and for how expan-
sion will occur on different soil types.
3
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
Table 1. Variables used in land change model.
Variable Source
Elevation INEGI
Slope Calculated from Elevation
Soil Group INEGI
Vegetation Type INEGI
Distance to Roads Calculated from INEGI Roads Data
Distance to Cities Calculated from INEGI Settlement Data
Distance to All Settlements (Rural and Urban) Calculated from INEGI Settlement Data
Distance to Avocado Packing House Calculated from SENASICA Data
Distance to Existing Agriculture Calculated from INEGI Land Use Data
Protected Areas Global Forest Watch
Present Mean Annual Temperature, Annual
Precipitation
Centro de Ciencias de la Atmósfera at the Universidad
Nacional Autónoma de México
Projected Mean Annual Temperature, Annual
Precipitation for 2041–2060 (RCP 2.6 and RCP 8.5)
WorldClim
Communally Managed Land Registro Agrario Nacional
This Monte Carlo approach was also used to
query the physical environmental characteristics of
where avocado is most likely to expand, includ-
ing elevation, slope, mean annual temperature, and
annual precipitation. For each simulation, the min-
imum and maximum values for these variables in
areas of avocado conversion were extracted, resulting
in a distribution of these values across 10 000 sim-
ulations (e.g. for 10 000 simulations of land change
to avocado, 10000 minimum elevations values of
the converted land were extracted). The distribu-
tions were then compared to the actual minimum
and maximum values for elevation, slope, temper-
ature, and precipitation from the observed avocado
expansion between 1992 and 2017 using the Mann-
Whitney U test for non-parametric data. The pur-
pose of these tests is to understand if these values
in our projections for expansion between 2017 and
2050 differ significantly from the observed values
from expansion between 1992 and 2017, signifying
a change in the ecological range where avocado is
planted.
2.5. Data
The dependent and independent variables were com-
piled from multiple different datasets in order to cre-
ate variable raster layers with a 100 m resolution
for the entire study area. Biophysical variables (elev-
ation, slope, soil, vegetation, climate) are included
because they impact suitability for avocado growth.
The most suitable conditions for avocado production
occur between 1200 and 2500 m a.s.l. (Barsimantov
and Navia Antezana 2012), in areas with the pres-
ence of Andosols, mean annual temperature between
12 ◦C and 33 ◦C (Whiley and Winston 1987), enough
moisture (via rainfall or irrigation) to meet high water
demand of avocado trees, and flat slopes to avoid
the construction of terraces. The distance variables
also affect likelihood of avocado expansion due to
the structure of the supply chain. Avocado produ-
cers sell their fruit on the tree to packing houses, who
hire harvesters to collect the fruit and transport it to
packing houses. As such, accessibility (i.e. distance to
roads, settlements) and proximity to packing houses
affect the price packing houses offer to producers, and
thus the profitability of an orchard. Finally, land ten-
ure (i.e. communally managed, known as ejidos, or
protected areas) is included as it also affects grower
decision to expand avocado. The variables used in the
model (and their sources) are listed in table S1, and
the process for creating these layers is described in
more detail in the SI document, section 1. To eval-
uate the performance of our approach for including
regional spatial correlation, we also estimated a stand-
ard (non-spatial) probit regression and compared its
prediction accuracy to our spatial probit model (SI
document, section 9).
3. Results
3.1. Estimation of the amount of avocado
expansion
The three scenarios of expansion based on trends in
SIAP data resulted in estimates of 977 km2, 1017 km2,
and 991 km2of expansion, respectively, between 2017
and 2050. The middle-range scenario of 1.5% annual
growth, based on the FAO report on tropical fruits,
resulted in 1073 km2of expansion (figure 2). The four
estimates of expansion are very similar, with an aver-
age of 1014 km2. We therefore used a rounded value
of 1000 km2, a 74% increase since 2017, (or 100 000
cells of 100 ×100 m) to represent likely expansion
to 2050. This area was allocated spatially according
to the probability model derived from the spatial
probit regression across the Avocado Belt, which is
24 674 km2in total area, with 1356 km2of avocado
groves existing in 2017 (INEGI).
3.2. Spatial allocation model
3.2.1. Spatial probit regression
Of 26 variables evaluated, only four were found to
be not significant statistically (see SI table S2). The
4
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
Figure 3. Encroachment of avocado production on protected areas. The spatial allocation of the 1000 km2that have the highest
probability of conversion to avocado production according to the land change model under the RCP 2.6 climate change scenario
are shown in yellow. The extent of avocado expansion from 1992 to 2017 is shown in purple. Protected Areas are shown in green.
Pico de Tancítaro is shown on the bottom left panel and the Monarch Butterfly Reserve is shown on the bottom right panel.
distance variables (to roads, packing plants, local vil-
lages, and agricultural areas) had the expected negat-
ive sign with the exception of distance to cities, which
indicated a higher probability of avocado away from
cities. This result is robust across specifications (SI
8 and SI 9) and is likely due to higher land prices
near cities from competing alternative uses (e.g. res-
idential, fields for vegetable gardens and dairy farm-
ing). Properties near cities tend to be smaller and
more fragmented (Fujita 1989), which also increases
production costs due to scale. The probability drops
substantially as distance to roads and to all localities
increases. It is important to mention that these dis-
tances will change over time, which is not accoun-
ted for in model projections. A 1 km increase in dis-
tance to roads and locality is associated with a drop of
0.008 and 0.006 in the probability of avocado respect-
ively (table S4). This represents a change of 21% and
16% with respect to the naïve probability of 0.0361
(i.e. number of cells classified as avocado over all cells
in our study area). Figure 3shows the spatial distri-
bution of the cells with the highest probabilities of
change to avocado orchard up to 1000 km2.
Within the Avocado Belt, the coefficient for elev-
ation is positive and its quadratic term negative,
indicating that the probability of avocado planta-
tion increases as elevation rises to 1538 m (inflec-
tion point) when probability starts to decline. This
is consistent with the literature that describes a rela-
tionship between avocado production and elevation
(Barsimantov and Navia Antezana 2012, Dubrovina
and Bautista 2014). However, the average partial
effect of elevation is quite small, (table S4). Precip-
itation and temperature also behave similarly, with
inflection points around 1707 mm yr−1and 24.9 ◦C
but partial effects are negligible.
These results may indicate the role of technolo-
gical adoptions that have allowed farmers to over-
come certain environmental limitations, including
better-adapted varieties and use of irrigation, or
alternatively, it may indicate exceptionally strong
economic incentives to grow avocado, even on
lands deemed agronomically inferior (Dubrovina and
Bautista 2014).
All of the soil group variables that were included
in the analysis had positive coefficients, with Andosol
having the largest magnitude coefficient with an aver-
age partial effect of 0.02% or 60% of the naïve prob-
ability. This result is in agreement with other stud-
ies which find that the volcanic Andosols are ideal
for avocado growth (Dubrovina and Bautista 2014),
and it means that spatial patterns of future avocado
expansion can be partially predicted by presence of
Andosols, a well-structured and well-drained vol-
canic soil relatively rich in nutrients (IUSS Working
Group WRB 2014).
In terms of land tenure, ejido lands are less likely
to have avocados. This may be because, although ejido
lands are legally alienable, many are still commun-
ally governed, meaning group approval is needed for
5
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
Figure 4. Distributions of area lost for avocado expansion by 2050 on each land type across 10 000 Monte Carlo simulations
under current climate and two different climate change scenarios (RCP 2.6 and RCP 8.5). Units are in hectares.
transfer or sale. The variable ‘protected areas’ was not
statistically significant in the spatial model, suggesting
that protected areas had no effect on preventing avo-
cado conversion. This is likely because the largest pro-
tected areas in the region allow for sustainable land
use within their buffer zones. Our data also show over
2 k ha of avocados inside protected areas.
Avocado plantations are highly spatially correl-
ated as indicated by the spatial regional effect para-
meter ρ=0.79. In all, the model performs well and
correctly predicts 81% of the existing avocados on
a cell-by-cell basis and more than 99% of the non-
avocado cells, a performance much superior than the
standard probit model (SI document, sections 5 and
9 respectively).
3.2.2. Different climate scenarios
When compared to probabilities under current cli-
mate conditions, probabilities of avocado expansion
decrease in the central-western portion of the belt and
increase in the eastern side of the region, near the
Monarch Reserve, for both RCPs. Larger increases in
probability are observed under RCP 2.6 (figure S6(a))
than under RCP 8.5 (figure S6(b)). This is likely due
to more pronounced changes in precipitation and
milder increases in temperatures for the former scen-
ario. A correlational analysis shows that change in
probability of avocado expansion is positively cor-
related to change in precipitation and negatively
correlated with change in temperature (figure S9). In
other words, places with higher future precipitation
will have higher probabilities of land change for avo-
cado, while places that will have higher increases in
temperature will have lower probabilities of avocado.
Our models predict that scenario RCP2.6 will increase
the probability of avocados over an area of 335 k ha
when compared to the current climate, but 1.16 mil-
lion ha will have lower probabilities across the Avo-
cado Belt. Scenario RCP8.5 is even less favourable to
avocados; only 238 k ha will observe increases whereas
probabilities will decline in 1.25 million ha. These res-
ults are in agreement with recent models that predict a
reduction in the potential area for avocados in Mexico
under climate change (Charre-Medellín et al 2021).
Because of this dynamic, our simulations of
avocado expansion under climate change show
less expansion in pine and pine-oak forests and
more expansion into all other vegetation types than
if expansion happened under current climate condi-
tions (figure 4).
3.2.3. Types of forest loss and protected area
encroachment
The projected amounts of forest loss, by forest type,
averaged across 10 000 Monte Carlo simulations are
shown in figure 4. The difference in estimates between
the RCP 2.6 and 8.5 scenarios is minimal. The forest
type predicted to experience the highest amount of
6
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
Table 2. Avocado expansion onto different soil types in the past and future under RCP 2.6.
Soil group
Percentage of avocado
expansion in 2017–2050
Percentage of avocado
expansion 1992–2017
Difference between
time periods
Andosols 33.477.2−43.8
Luvisols 28.5 9.7+18.8
Leptosols 13.1 7.5+5.6
Regosols 8.9 1.1+7.8
Vertisols 6.5 1.3+5.2
Phaeozems 6.0 2.2+3.8
Cambisols 2.4 0.9+1.5
absolute loss is pine-oak forest, for which the mean
amount of loss across simulations is 265.1 km2under
RCP 2.6 and 264.1 km2under RCP 8.5 (tables S3(a)–
(c)). Notably, pine-oak forest is the most prominent
forest type within the study area, and these values of
loss represent an approximately 7% loss of pine-oak
forest from the Avocado Belt and a 4% loss of pine-
oak forest from the entire state.
Rarer forest types are also at risk, such as oyamel
fir forest and mesophilic montane forest. A projected
loss of 13 km2of oyamel fir forest (under both RCPs)
constitutes a loss of 6% of this forest type from the
whole state. Similarly, a loss of just 11 km2of meso-
philic montane forest represents an 8.5% loss of this
forest type from the state. These are relatively uncom-
mon forest types, making their potential loss of con-
servation concern.
The predicted mean area of avocado encroach-
ment into all protected areas, under both climate
change scenarios, is 36 km2. This amount is almost
entirely made up of encroachment on federally pro-
tected areas, for which the mean predicted loss equals
35 km2. The largest federally protected areas within
the Avocado Belt are the Monarch Butterfly Preserve
and the Pico de Tancítaro. The spatial allocation of
the highest probability cells of conversion to avocado
production show a potential spatial distribution of
avocado expansion within these areas (figure 3). State
protected areas are also vulnerable to land change for
avocado production, with a predicted conversion area
of 0.9 km2. These areas include sustainable use areas
(per the IUCN protected area categorization) and
urban-periurban parks. Taken all together, this level
of encroachment would represent 6.7% of the total
protected area within the Avocado Belt. These data
may be useful in the design of park-people programs
meant to manage the protected areas while providing
benefits to local people.
3.2.4. Avocado range expansion
Mann Whitney U tests showed that the distribu-
tions of minimum and maximum elevation, slope,
and annual mean temperature are all statistically
significantly different than the observed values of
these variables in the areas of avocado expansion
between 1992 and 2017. This implies that the ranges
of elevation, slope and temperature are widening for
the spatial distribution of avocado production as it
expands into new lands. Future avocado production
is predicted to expand into both higher and lower
elevations, into hotter and colder places, and onto
steeper and flatter slopes. It is important to note,
however, our models predict 169–229 ha (out of
100 k ha) of avocado plantations above 3000 m (with
a maximum of 3136 m). This is likely due to the
strong spatial effect whereby avocado plantations in
high elevations (i.e. near 3000 m) induce predictions
of future expansion at higher elevations at nearby
cells.
For precipitation, the distribution of minimum
precipitation values for projected expansion is signi-
ficantly different than the observed minimum pre-
cipitation of avocado expansion between 1992 and
2017. This indicates that future avocado expansion is
also predicted to occur in drier areas than have been
utilized previously. There is no significant difference
between the distribution of maximum precipitation
for future avocado expansion and the observed max-
imum precipitation of avocado expansion between
1992 and 2017. This is likely because the wettest areas
where avocado expansion occurred between 1992 and
2017 were already close to the upper limit of annual
precipitation in the entire Avocado Belt. In other
words, there are not many wetter areas into which
avocado expansion could occur.
Results from Monte Carlo simulations measuring
avocado expansion onto different soil groups found
that the greatest amount of expansion is projected to
happen in Andosols (table 2). The mean across sim-
ulations for expansion into Andosols is 334.17 km2
under RCP 2.6 or 331.74 km2under RCP 8.5;
both represent 33% of the total expansion. Andosols
are followed by Luvisols (285.42 km2under RCP
2.6), Leptosols (131.08 km2), Regosols (89.05 km2),
Vertisols (64.74 km2), Phaeozems (59.83 km2), and
Cambisol (23.99 km2).
Andosols are the most suitable soil for avocado
growth, and it is the most prevalent soil group in
the Avocado Belt. It is unsurprising, therefore, that
much of the projected avocado expansion occurs
on them. However, the proportion of expansion
that would occur on Andosols between 2017 and
7
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
2050 (33%) is lower than the proportion of avo-
cado expansion between 1992 and 2017 that has
been observed on Andosol (77.23%). Subsequently,
projected expansion is on a higher proportion of all
other soil groups than previous expansion (table 3).
For example, expansion from 1992 to 2017 occurred
9.7% on Luvisols and 7.5% on Leptosols. Projected
expansion from 2017 to 2050, on the other hand,
occurs 28.5% on Luvisols and 13.1% on Leptosols.
All of these relations would be important for making
agronomic recommendations.
4. Discussion
Although Michoac´
an is known in Mexico for its high
productivity for avocado, the amount of land with
the ideal biophysical characteristics cannot satisfy the
projected increase in avocado production caused by
increasing global demand. If the predicted demand is
met by orchard expansion within the Avocado Belt,
it will entail the conversion of more marginal lands.
Thus, the spatial distribution of projected avocado
expansion into the year 2050 has important implica-
tions for ecosystem degradation and risk for growers.
More generally, the overall strategy of making pre-
dictions based on both environmental and social/in-
frastructure variables can be used to evaluate the
landscape and regional implications of other global
commodities.
This model, of course, has limitations that may
cause predictions to differ from future realities. First,
the model assumes that future avocado expansion will
be driven by the same forces, to the same degree,
associated with past conversion. Moreover, the model
assumes a worst case scenario where all demand
growth is met by conversion of forest to avocado pro-
duction, and as such, it does not include conversion of
existing other agricultural lands to avocado orchard.
Since avocado expansion is not yet prolific in mar-
ginal areas, there is a degree of uncertainty about the
limitations that water, soil, or climatic extremes may
place on expansion. Past data may be inadequate for
projecting how expansion will occur at such extremes.
Similarly, the model does not include a dynamic
learning process from failed orchards in marginal
areas. In terms of future landscape conditions, the
model does not account for unknown changes in
infrastructure, like roads and settlements, which will
likely change as a result of avocado expansion itself.
Furthermore, climate change projections are applied
statically using 2050 temperature and precipitation
estimates, rather than incrementally. As such, defor-
estation estimates should be seen as extreme end
member estimates. Finally, besides land tenure, the
model does not account for other political or eco-
nomic variables that may affect expansion, and it does
not attempt to measure expansion into existing agri-
cultural areas.
4.1. Ecosystem degradation
Understanding the types of forest that are most vul-
nerable to loss from avocado expansion can improve
understanding of the biodiversity threats of increas-
ing avocado production and target responses or pre-
ventive actions. According to our modeling, pine-oak
forests are vulnerable to the largest absolute area loss
from expansion in the Avocado Belt of Michoac´
an.
These forests are generally made up of Pinus and
Quercus species, but can also have species of associ-
ated genera, such as Alnus, Crataegus, Clethra, and
Arbutus (Cruz Angón et al 2019). In addition to their
biodiversity value, pine-oak forests have been found
to have higher carbon storage capacity than other
anthropogenic land uses in the region (like avocado
orchards and other agriculture) (Ordóñez et al 2008).
Loss of pine-oak forests would result in a net source
of carbon into the atmosphere, a concern for global
climate change.
Beyond pine-oak forests, loss of mesophilic mont-
ane forests and oyamel fir forests is of national and
global concern. Although the total area of mesophilic
montane forest projected to be lost is much lower
than that of pine-oak forest, such loss represents a
high percentage of this already rare forest type. Meso-
philic montane forests are highly biodiverse but are
rare and fragmented within Michoac´
an. As such, any
loss would have a big proportional impact on the eco-
system type and the species the rely on it for habitat.
This forest type includes tree species of genera such as
Alnus, Clethra, Pinus, Quercus, Styrax, and Symplocos,
with numerous epiphytes (Cruz Angón et al 2019).
Oyamel fir forest is similarly rare within Michoac´
an,
as it is restricted to small areas with high altitudes
(2600–3500 m asl) and high humidity. These forests
are dominated by Abies religiosa, and they are of par-
ticular conservation importance since they serve as
the southern migration and winter hibernation hab-
itat for monarch butterflies (Danaus plexippus) (Cruz
Angón et al 2019).
Loss of oyamel fir forest is linked to the model
results showing encroachment of avocado expansion
into protected areas. The results show that most of
the projected encroachment would happen on fed-
eral protected areas, including into the margins of the
Monarch Biosphere Reserve (MBR). This reserve is
already designated as being of ‘significant concern’
by the IUCN World Heritage Outlook because of the
loss and degradation of forests in both the buffer and
core zones (IUCN World Heritage Outlook 2020).
Recent studies confirm avocado expansion into the
buffer zone of the MBR between 2006 and 2018 and
warn of the risk of future expansion in the Reserve
(S´
aenz-Ceja and Pérez-Salicrup 2021). The IUCN
report does not identify avocado as a specific risk, and
instead describes the vulnerability of the reserve to
logging, poorly managed tourism and livestock graz-
ing. Vulnerability to avocado expansion puts further
pressure on this already threatened reserve and must
8
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
be considered by development agencies promoting
avocado production. Yet, some critics question the
idea of strictly protected natural areas, arguing that
the designation of a core area free from human dis-
turbance undermines sustainable community forest
management and leaves the fir forests even more vul-
nerable to exploitation (Gonzalez-Duarte 2021).
In addition to types of forest loss and encroach-
ment into protected areas, the expansion of avocado
production onto higher slopes risks increased soil
erosion, an already existing threat (Dubrovina and
Bautista 2014). Moreover, increased proportion of
growth on Leptosols and Regosols would increase risk
of soil erosion because of these soil groups’ lower
water infiltration capacity (IUSS Working Group
WRB 2014). Degradation of soil poses even more risk
for existing vegetation and water resources in these
ecosystems, which in turn, further threatens the biod-
iversity within these habitats.
4.2. Uncertainty for growers
The widening crop niche of avocado production
does not only pose risks of ecosystem degradation;
it also increases risks for growers, as many of these
marginal lands have lower suitability for avocado
growth. As avocado is projected to expand into higher
and lower elevations, higher and lower temperatures,
lower precipitation, and less suitable soil groups, pro-
duction may be more vulnearable to weather fluctu-
ations. This in turn may lead to increased application
of inputs such as fertilizer, pesticides, herbicides,
and irrigation, furthering impacting the surround-
ing ecosystem. Water scarcity and chemical pollu-
tion of groundwater are already problems in the state
(Borrego and Allende 2021).
The range of annual mean temperature where
avocado expansion occurred between 1992 and 2017
was 11.2 ◦C–24.3 ◦C. The mean minimum and
maximum values for mean annual temperature pro-
jected for avocado production in 2050 are 7.1 ◦C
and 28.5 ◦C, respectively. This projection pushes
avocado production beyond previously established
optimal range for productivity. Previous studies place
the temperature range for avocado at 12 ◦C–33 ◦C
(Whiley and Winston 1987), although the ideal range
is 20 ◦C–25 ◦C. Above temperatures of 28 ◦C, avocado
trees can lose flowers (Lovatt 1990).
Our results show that projected avocado expan-
sion may occur in areas of lower annual precipita-
tion. This would likely increase irrigation demand in
these areas, as avocados are a water-intensive crop
(Quiroz Rivera 2019, Charre-Medellín et al 2021).
This potential impact of expansion raises concern
since issues of water scarcity have been the cause of
conflict over water allocation in the region in the past
(Alarcón-Ch´
aires 2018). Use of more marginal habit-
ats requires more investment for irrigation and other
more costly landscape management approaches.
Avocado expansion in the past was partially
enabled by the presence of Andosol soils, but dwind-
ling availability means expansion will increasingly
occur in different soil groups. Andosols, Luvisols and
Phaeozems have been found to be suitable for avo-
cado production, with the first being by far the most
suitable due to their deep profiles, high capacity for
water infiltration and water retention (Dubrovina
and Bautista 2014). Luvisols, while still relatively suit-
able for avocado, have a higher clay content and
thus require the construction of berms within orch-
ards to allow for proper root development, mak-
ing the cost of production of avocado on Luvisols
higher than that for Andosols. Beyond these three
aforementioned soils groups, Cambisols, Regosols,
Leptosols, and Vertisols have low suitability for avo-
cado (Dubrovina and Bautista 2014) and thus may
considerably impact an orchard’s productivity.
In addition to environmental concerns, avo-
cado expansion may turn out to be a risky invest-
ment. Although avocado is currently highly profit-
able (Borrego and Allende 2021, Denvir et al 2022),
production in less than ideal environments is likely
to be more risky and therefore more vulnerable to
negative market shocks or abnormal weather events.
Compounding matters further, our climate change
simulations indicate a net reduction in the suitab-
ility for avocados in Michoac´
an, as indicated by an
overall reduction in spatial probabilities. Currently,
Michoac´
an holds exclusive access to the US mar-
ket, but negotiations are under way to allow other
regions of Mexico to export to the US. For instance,
the state of Jalisco has won approval and will soon
ship fresh avocados to the US. Moreover, there are
reports of neighboring states smuggling avocados into
Michoac´
an in order to export them to the U.S. This
activity is illegal and under-studied and no reliable
data exist on the quantities involved. For that reason,
this aspect of illegal indirect land use change is not
included in this analysis but could be a focus of future
research. With more competition, profitability of avo-
cados in Michoac´
an may decline. From a societal per-
spective, questions remain if the financial benefits of
this risky investment in avocado expansion are worth
its environmental costs.
Avocado expansion is just one of the various
threats to forests in Michoac´
an. Future research
could consider additional socioeconomic and polit-
ical factors that will direct future expansion of avo-
cado and how they interact with other threats, such
as cattle ranching, illegal logging, berry production,
and urban settlement. Variables like market prices
and grower access to capital are likely important in
deciding which growers participate in the expansion
of avocado, which were not evaluated here. Moreover,
Michoac´
an is currently the only state in Mexico that
is authorized to export avocados to the United States,
which is by far Mexico’s largest export market. It is
9
Environ. Res. Lett. 17 (2022) 034015 E Y Arima et al
reasonable to ask how the spatial distribution of avo-
cado expansion will be affected once avocado exports
to the U.S. from other Mexican states, such as Jalisco,
are allowed. Would such a situation relieve pressure
from forests in Michoac´
an? Or would it cause sim-
ilar problems in other states, where growing condi-
tions are not as ideal as Michoac´
an? An approach
such as outlined by Denvir et al (2022), which calls
for targeted sustainability action at different parts of
the supply chain, would allow for also addressing the
sustainability concerns invoked by the roles of dis-
tributors and wholesalers, who in conjunction with
growers and consumers, affect the social and envir-
onmental costs of a globally sought-after commodity.
This general approach could prove useful for assessing
the socioenvironmental consequences of many other
food commodities.
Data availability statement
The data that support the findings of this study are
available upon reasonable request from the authors.
Funding
We received funding from the ConTex program (no
Grant Number), which supports research collabor-
ation between the Consejo Nacional de Ciencia y
Tecnología (CONACyT) and the University of Texas
system.
Acknowledgments
We would like to thank the ConTex Program, the
Department of Geography and the Environment at
the University of Texas at Austin, and the Lozano
Long Institute of Latin American Studies for sup-
porting our fieldwork, and two anonymous referees
and the Editor whose comments greatly improved the
quality of the manuscript.
ORCID iD
Eugenio Y Arima https://orcid.org/0000-0003-
3366-4287
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