Ramirez_Road-ecology_1152212852

Journal of Maps, 2006, 181-190
Land Cover and Road Network Map for the
Monarch Butterfly Biosphere Reserve in
Mexico, 2003
M. ISABEL RAMÍREZ1 , RUTH MIRANDA2 , RAÚL ZUBIETA3 and
MARGARITA JIMÉNEZ4
1 Unidad
Académica Morelia, Instituto de Geografı́a, Universidad Nacional Autónoma de México,
Antigua Carretera a Pátzcuaro, 8701. CP 58190, Morelia, Michoacán, MÉXICO;
[email protected]
2 Departamento
de Geografı́a y Ordenación del Territorio, Universidad de Guadalajara, Av. de los
Maestros y Mariano Bárcena, CP 44260, Guadalajara, Jalisco, MÉXICO; [email protected]
3 Departamento
Geografa Fı́sica, Instituto de Geografı́a, Universidad Nacional Autónoma de México,
Circuito Exterior s/n. Ciudad Universitaria, CP 04510, México DF, MÉXICO; [email protected]
4 Comisió
Nacional para el Uso y Conocimiento de la Biodiversidad, Liga Periférico-Insurgentes Sur 4903,
CP 14010, México DF, MÉXICO; [email protected]
(Received 6th July 2006; Accepted 27th August 2006)
Abstract: To preserve the monarch butterfly (Danaus plexippus L.) overwintering sites
in Mexico, the fir forests used for the main colonies have been protected by three
presidential decrees, in 1980, 1986 and 2000. The territory of the current Monarch
Butterfly Biosphere Reserve (MBBR) belongs mainly to communal properties (ejidos
and indigenous communities). Contrary to expectation, this protected area is still facing
severe disturbance and loss of forest cover, because of intensive illegal and legal logging,
and subsistence farming activities. Roads are landscape elements well known as a cause
of disturbance and deforestation. Therefore, the aim of this map is to illustrate the road
network and land cover relationship in the MBBR, taking into account the land tenure.
The roads vector layer was obtained by photointerpretation of one meter resolution
digital aerial photograph mosaics from March 2003, and one meter resolution Ikonos
pansharpened images from March 2004, as well as field work, using GPS georeferenced
tracks. Land cover polygons were constructed by visual interpretation of January 2003
Landsat ETM+ color composites, simultaneously verified with the aerial photograph
mosaics. The final 1:75000 map shows very high human pressures over the reserve
forests. This is expressed by a high density road network, composed mainly of tertiary
roads opened to wood extraction, in many cases illegally, and incompatible with the
protection category of these forests.
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ISSN 1744-5647
http://www.journalofmaps.com
Journal of Maps, 2006, 181-190
Ramı́rez, M.I., Miranda, R. et al
1. Introduction
The Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico is
home to one of the world’s most spectacular ecological phenomena: millions
upon millions of monarch butterflies each autumn fly from Canada and
United States to winter on a few hectares of fir forests. Since this
overwintering habitat was first described in 1976, three presidential decrees
have been issued to protect it (1980, 1986, and 2000). The first decree did
not delimit specific boundaries. The 1986 decree designated 4,481 hectares
as “core zone” in which all logging was prohibited, and 11,629 hectares as
“buffer zone” in which limited logging was permitted. The 2000 decree
extended the protected area to 56,259 hectares, under Biosphere Reserve
category (Diario Oficial, 2000), with 13,552 hectares in core and 42,707
hectares in buffer. Nevertheless, severe forest loss and disturbance have
been ongoing, and threaten the butterfly overwintering phenomenon
(Brower et al., 2002; Ramı́rez et al., 2003).
The forest loss and disturbance is due to forest extraction and farming
activities, which require ways to access and transport products. Roads
provide social and economic benefits, since they decrease the transportation
costs, and allow communication and movement of goods and services
between communities. Moreover, roads are necessary for beneficial forest
activities, including appropriate forest management, fire and pest control,
recreation, and wild life conservation (Tchikoué, 2002; Forman, 2003).
Nevertheless, roads produce short and long term negative effects on the
ecosystems they go through. Some of these effects are direct loss of
vegetation and soil; changes in hydrologic patterns, microclimatic
conditions, floristic composition and wildlife behavior; increased risk from
landslides, and human access leading to excessive resource extraction
(Spellerberg, 1998; Forman, 2003). Therefore, the road structure, density,
function, and effects have become important aspects of environmental
analysis. Mitigating the negative effects of roads through planning,
conservation, management, and environmental policies represents a large
challenge to science and society (Forman and Alexander, 1998).
The most recent official maps of the MBBR (updated through 1995 aerial
photographs) (INEGI, 2000), and their finest scale (1:50000) are not
sufficient to explore the present road network of the reserve forests. Thus
the objective of this work is mapping the current MBBR roads at detailed
scale (1:25000) in relation to the forest condition, and to the land
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Journal of Maps, 2006, 181-190
Ramı́rez, M.I., Miranda, R. et al
ownership.
2. Study Area
The map covers a rectangle of 140,000 hectares straddling the border
between the states of Mexico and Michoacan. The bounding coordinates
are 19◦ 18’ to 19◦ 45’ North and 100◦ 08’ to 100◦ 24’ West. Within this
area, 54,489 hectares belong to the MBBR main area: 12,963 hectares of
core zone, and 41,526 of buffer zone. That represents 97% of the Reserve;
the remaining 3% (1,770 hectares) is in an isolated area, at Cerro
Altamirano, 30 km north of the main block (Figure 1). The road analysis is
focused at the protected area.
The MBBR is in the Transverse Volcanic System, which was formed by
Tertiary and Quaternary volcanic activity. Thus andesitic and basaltic
rocks are predominant, and the soils are mainly andosols, acrisols and
luvisols. These soils are poor for agriculture, but suitable to support forest
vegetation. This area is characterized by its temperate-humid ecosystem,
composed of conifer (Abies, Pinus and Cupressus) and broad-leaved
(Quercus, Alnus, Arbutus, etc.) forests (Azcárate et al., 2003).
Although the MBBR has official protected status, the land is in private
rather than government ownership. The whole MBBR is divided in more
than 100 properties. Of these, 70 are communal properties (57 ejidos and
13 indigenous communities), one is federal property, one is state land, three
are in dispute, and the remaining are single owner private lands (CONANP,
2001). They are part of six municipalities of Michoacan and four of Mexico
State. Ownership boundaries do not coincide with MBBR boundaries:
many individual properties include areas within both the core and buffer
zones, and some extend outside the reserve boundaries (Figure 1).
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Journal of Maps, 2006, 181-190
360000
Ramı́rez, M.I., Miranda, R. et al
380000
U.S.A.
MEXICO
MICHOACAN
2200000
2200000
C. Altamirano
2180000
2180000
2160000
MEXICO STATE
2160000
Gulf of
Mexico
Pacific
Ocean
Mexico
State
Michoacan
Map area
MBBR Core zone
MBBR Buffer zone
Land property
State border
2140000
2140000
UTM Zone 14
Datum WGS84
Ellipsoid GRS80
0
360000
10 Km
380000
Figure 1: Localization of the Monarch Butterfly Biosphere Reserve, and its relationship with
land property.
3. Materials and Methods
To generate the base map, we used digital topographic and vector layer
maps, both at 1:50000 scale (INEGI 2000), and two meter resolution digital
orthophotos from 1994 produced by the Mexican National Institute of
Geography, Statistics, and Informatics (INEGI). Our work was developed
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Journal of Maps, 2006, 181-190
Ramı́rez, M.I., Miranda, R. et al
over mosaics of one meter resolution digital aerial photographs (DAP) from
March 2003 (Peralta et al., 2001; Honey et al. 2004). We also used Ikonos
pansharpened images from March 2004 and Landsat images from January
2003, 1 and 30 meters resolution, respectively (Figure 2).
For the road map, we used the INEGI’s roads vectors and their
classification, and we updated them by interperting the DAP mosaics and
Ikonos images visually on the computer screen. We considered four
categories: 1) paved roads, well engineered, covered by asphalt or concrete;
2) gravel roads, some engineering, covered by gravel or compacted sand; 3)
earthen roads, hardly any engineering, without any cover; 4) foot paths,
abandoned earthen roads or paths opened by hand tools maintained by
frequent walking.
Simultaneously, we visually interpreted Landsat 453 and 752 color
composites to obtain the land cover map, verifying each delimited polygon
using the DAP mosaics and Ikonos images. 15 land cover types were
identified: 4 types of dense forest, 4 types of disturbed forest (opened or
fragmented), secondary shrubs, dense scrubs, disturbed scrubs, grassland,
seasonal crops, irrigated crops, and barren ground.
Roads were photointerpreted using the same on-screen 1:10000 scale to
obtain a 1:20000 final vector map. Likewise land cover was interpreted at
1:40000 to get a 1:75000 final vector map. Draft maps were verified by field
work carried out between July 2003 and March 2004. We visited 46
properties, tracking more than 12.5% of the photointepreted roads. Using
the track mode of Garmin GPS units (III+, and eTrexVista), we verified
57% of the paved roads, 37% of the gravel roads, 10% of the earthen roads,
and 6% of the footpaths. Estimated positional accuracy of mapped road
lines was less than 25 meters, <0.3 mm in scale of 1:75000. Also, we took
228 GPS check points of land cover to estimate accuracy by applying a
confusion matrix. The result indicated a map global accuracy of 90%.
However, considering DAP mosaics and Ikonos visual validation, most of
misclassified points are not map class errors, but heterogeneity within
polygons (Figure 2).
Despite the finer scale of the road features, the final map combining both
layers is presented at 1:75000 scale.
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Journal of Maps, 2006, 181-190
Ramı́rez, M.I., Miranda, R. et al
Figure 2: Example of same view on Peralta’s 1:10000 DAP mosaic (left) and 1:40000 Landsat
image (upper right). In DAP mosaics roads, and heterogeneity within main land cover classes
can be seen.
4. Conclusions
The photointerpretation of the DAP mosaics shows that inside the MBBR
there is a road network of 2574 kilometers: 55% are earthen roads, 37% are
foot paths, and remaining 8% are paved and gravel roads. Thus, within the
Reserve the average road density is 4.7 km/km2 (Ramı́rez et al., 2005). It
appears to be associated more strongly with land ownership than with
Reserve boundaries, since there is no significant difference between the core
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Journal of Maps, 2006, 181-190
Ramı́rez, M.I., Miranda, R. et al
zone and buffer zone (Table 1).
In areas of similar environmental conditions devoted to forest extraction in
Mexico, it is recommended that road density be less than 4 km/km2 (40
m/ha) to avoid triggering severe erosion processes (Tchikoué, 2002).
Considering only paved, gravel and earthen roads, in this protected area we
found 14 properties where density is higher than 4 km/km2 . Even in Ejido
Emiliano Zapata, at buffer zone, road density reaches 12 km/km2 (Ramı́rez
et al., 2005).
The conservation implications of the extensive road network are clear. The
map demonstrates that the properties with higher densities of earthen
roads and paths are also the properties with a greater extent of disturbed
forest. Furthermore, the chaotic road distribution pattern is evidence that
many of them have been opened without any planning, and without legal
authorization. This is additional evidence of what is considered to be the
highest conservation concern for the MBBR: illegal logging (WWF-Mexico,
2004). This study maps the road network and land cover as of 2003; as of
summer 2006, illegal logging and road creation are continuing at an
untenable rate.
Finally, the spatial patterns of forest conservation and forest disturbance
are related to property and political boundaries rather than to official
protection limits, indicating that current management regulations and
enforcement are not adequate. The existing road network is dense enough
to compromise the viability of the Reserve; in use and abandoned earthen
roads closures need to be enforced to limit the accessibility of remaining
conserved forests patches.
Road
type
Core zone
Paved
Roads
Gravel
roads
Earthen
roads
Foot paths
Total
Density (km/km2 )
Length (km)
Total
Core zone
3
Buffer
zone
45
Total
0.1
Buffer
zone
0.02
48
9
134
143
0.1
0.1
0.3
290
1129
1419
2.2
2.2
2.6
265
566
699
2008
964
2574
2.0
4.4
2.0
4.4
1.8
4.7
0.1
Table 1: Road length and road density by protected zone at the MBBR
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Journal of Maps, 2006, 181-190
Ramı́rez, M.I., Miranda, R. et al
Acknowledgements
We thank WWF-Mexico for financial support, and the Monarch Butterfly
Biosphere Reserve staff for field permits. We are especially grateful to the
members of the 46 ejidos and communities we visited, especially to those
people who guided us. Dr. Lincoln Brower and Dr. Linda Fink, of Sweet
Briar College, US, shared us part of the materials, discussed the project
and reviewed this manuscript. Carmen Luz, Laura Luna, and Sergio Cano
provided help in different activities.
Software
For land cover and road network visual interpretation Ilwis 3.0 and
ArcView 3.2 GIS were respectively used. ArcInfo 8.1 was used for edition
and topology building, and, FreeHand MX for designing and construction
of final map.
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