The research was undertaken within a series of study areas located within
highland Mexico and southern South America. Some general information
about these locations is provided below. Further information is provided
by Newton (2007).
Tropical montane forest
Neotropical montane forests are widely recognized as being of exceptional
conservation importance, being a centre of high diversity and endemicity
for many different groups of organisms. For example, some 45,000 plant
species are thought to be found in neotropical highlands, nearly a fifth
of all species known (Churchill et al. 1995). Cloud forests,
being those montane forests in the humid tropics that are frequently
covered in clouds or mist, have attracted particular conservation concern.
Research focused on montane forests in three areas of Mexico (Fig. A1):
(i) Xalapa, Veracruz. The study area is situated between 1200
and 2000 m of altitude in the eastern Sierra Madre mountains, and is
located between 19°13' and 19°41' N, and 96°51' and 97°01'
W, with an area of 842 km². Total annual precipitation in this
region varies between 1300 - 2200 mm, while mean annual temperature
is between 12 – 18°C. Typically, there are three well-defined
seasons, the relatively dry-cool season lasting from October-November
to March, the dry-warm season during April and May, and the wet-warm
season from June to September-October. Soils are andosols. Some important
canopy tree species in the study area are Quercus xalapensis,
Liquidambar styraciflua, Q. leiophylla and Carpinus
caroliniana. Current land cover is a mosaic of cloud forest, secondary
forest, coffee plantations, pastures, agricultural crops and human settlements.
Most of the land is privately owned.
(ii) Highlands of Chiapas.
The Highlands of central Chiapas is a limestone massif, situated at
16°15' - 17°10' N, and 91°45' - 92°50' W, at altitudes
of 1500 – 2840 m. The climate is temperate sub-humid, with a mean
annual temperature of 13-17°C and mean annual rainfall typically
in the range 1100-1600 m. Soils are a mixture of thin rendzinas, deeper
humic acrisols and infertile chromic luvisols. Vegetation includes a
number of highly diverse forest formations including seasonal pine and
pine-oak forests, montane rain forests (800-2500 m elevation) and evergreen
cloud forests (>2500 m). Oaks and pines are usually dominant in the
forest canopy, including species such as the oaks Quercus laurina,
Q. rugosa and Q. crassifolia, and the pines Pinus oocarpa,
P. pseudostrobus and P. ayacahuite. The understorey
is typically dominated by a diverse shrub community, including species
such as Myrcia jurguensenii, Oreopanax xalapensis, Fuchsia spp.
and Litsea glaucescens. Most inhabitants belong to Mayan
ethnic groups, principally the Tzotzil, Tojolobal and Tzeltal. Land
is communally owned. Traditional agriculture involves slash-and-burn
(‘milpa’) involving the cultivation of corn, beans, and
squash, producing a landscape mosaic of vegetation at different successional
(iii) El Rincón Alto, Sierra Norte, Oaxaca. The
study area is the Sierra Madre de Oaxaca Mountain Range, located in
the north of the State of Oaxaca, between the parallels 17°18’
and 17°23’ N and the meridians 96°15’ and 96°21’
W. The area is part of the El Rincón Alto region and lies at
1850 + 150 m altitude, where tropical montane cloud forest is
the primary vegetation. Topography is mountainous and the slopes are
usually steep (15 - 64%). The climate is temperate-humid to subhumid,
with mean annual temperature ranging between 20-22°C and mean precipitation
around 1700 mm yr-1, with a rainy season in summer and a
dry season in winter. Soils lie on a bedrock of Mesozoic schist and
are classified as entisols, inceptisols and dystrudepts. The land cover
is a mosaic of primary forests, secondary forests of different ages
after abandonment, and agricultural fields. Successional forests are
dominated by the conifer Pinus chiapensis, which occurs
in association with other species such as Clethra integerrima, Gaultheria
acuminata, Liquidambar styraciflua and Phyllonoma laticuspis.
Late-successional forests are dominated by broadleaved
species such as Persea americana, Quercus spp., Rapanea spp.,
Ternstroemia hemsleyi and Quetzalia occidentalis. Human population
density is relatively low compared to the other Mexican study areas.
The area is inhabited by Zapotecs, a native Mexican ethnic group. Land
tenure is communal.
South temperate rain forest
Temperate rain forests are distributed along the coastal mountain range
of Chile and the main Andean range from 38°-56° S. Within
this area, a number of different forest types may be differentiated,
including the Valdivian evergreen forests that extend for 250
km from the Tolten River (40°50’ S) to south of the Llico
River (41°30’ S). Notable elements of the flora include the
long-lived conifers Monkey puzzle (Araucaria araucana) and alerce
(Fitzroya cupressoides), with some trees of the latter species
living for more than 3,620 years. Over the past 30 years, the Chilean
forestry sector has become a driving force in the national economy,
with forest exports increasing from approximately US$40 million in 1970
to US$2.2 billion in 2000. Other main threats to native forests have
been the conversion to pasturelands, human-set fires, highgrading (selective
felling), fuelwood cutting and other logging practices. Most land is
Fig. A-1. Map illustrating the location
of the principal study areas, namely Central Veracruz and the Highlands
of Chiapas, Mexico, and Rio Maule-Cobquecura (Regions VII and VIII)
and Los Muermos (Region X), Chile. Some field-based research was also
undertaken in neighboring areas, including Sierra Norte, Oaxaca (Mexico),
Chiloé Island (Region X, Chile), locations in Region IX (Chile)
and neighboring areas of Argentina.
While research activities were distributed throughout southern Chile
and adjacent locations in Argentina, investigations were particularly
focused on the following three areas of Chile:
(i) Los Muermos area, Region X, Chile.
The study area corresponds to 503,287 ha located between 41°30·
S, 73° W and 42°20· S, 74° W in southern Chile.
The zone is characterised by a rainy temperate climate with an oceanic
influence and without dry-periods, with a mean annual precipitation
of around 2000 mm. The landscape is dominated by Valdivian temperate
rain forests, surrounded by crops and pasture lands. Many of the remaining
forest occur on acidic, shallow, poorly-drained soils referred to as
ñadis, which are classified a gleysols. The forests are
characterised by the presence of broad-leaved evergreen tree species
such as Drimys winteri (Winteraceae), Nothofagus dombeyi (Nothofagaceae),
Laurelia philipiana (Monimiaceae), Amomyrtus luma, Amomyrtus
meli (both Myrtaceae), and Eucryphia cordifolia (Eucryphiaceae).
In some sites, long-lived conifers such as Fitzroya cupressoides
and Pilgerodendron uvifera (both Cupressaceae) can also be found.
Anthropogenic disturbance has led to early successional stages of the
forest being widespread, which are characterized by a high abundance
of D. winteri and N. nitida. In some degraded sites, shrub
species such as Berberis spp. (Berberidaceae), Baccharis
spp. (Asteraceae), and Gaultheria spp. (Ericaceae) are abundant.
(ii) Chiloé Island, Region X, Chile. The study
area comprises about 400 km2 in the north-eastern corner
of Chiloé Island, approximately 20 km north of the city of Ancud
(41º50· S, 73º50· W). The landscape is characterized
by an undulating topography with altitudes ranging from 50 to 100 m.
Soils are generally thin (< 1 m), originating from Pleistocene moraine
fields and glacial outwash plains, often with poor drainage. The prevailing
climate is described as wet temperate with a strong oceanic influence.
Meteorological records at Senda Darwin Biological Station (45º53·
S, 73º40· W) indicate an annual rainfall of 2,090 mm and
a mean annual temperature of 12ºC. Maximum monthly temperatures
(January) are 16ºC and minimum monthly temperatures (July-August)
are 5ºC. Rainfall occurs throughout the year, but 64% of the precipitation
is concentrated from April to September. Lowland forests in the area
have been logged since the early 1800s, but land clearing became more
intense in the second half of the 20th century. The present-day rural
landscape is characterized by a mosaic of remnant forest fragments and
grazing pastures. The major forms of human impact on forests during
the last century have been selective logging of valuable timber trees,
widespread use of fire to clear land for pastures, and increasing forest
The forests are dominated by evergreen, broad-leaved trees, but included
narrow-leaf conifers such as Saxegothaea conspicua and Podocarpus
nubigena. Floristically, many forests belong to the North Patagonian
forest type. Nothofagus nitida, Drimys winteri and Podocarpus
nubigena are widespread. Some sites are more typical of a Valdivian
rain forest with canopy dominants such as Eucryphia cordifolia,
Laureliopsis philippiana and Nothofagus nitida. All forests
have an understorey of Myrtaceae trees, often with abundant regeneration
of tree seedlings and saplings and abundant cover of the native bamboo
Chusquea quila, especially in tree-fall gaps.
(iii) Región del Maule, Chile. This study area covers
around 578,164 ha in the Coastal Range of the Maule and Bío-Bío
(VII and VIII) regions of south-central Chile, at latitudes between
35º and 36º30· S and longitudes between approximately
72º and 73º W. The climate is of Mediterranean type, with
an average annual rainfall of 700-800 mm concentrated in the winter;
the summers are dry from September to April, with high luminosity. The
mean annual temperature is 14ºC. The two main types of soil are
well-developed alfisoles, which have evolved from granite substrate;
and thinner inceptisoles usually originating from marine sediment rock
layers. The natural forest is mainly dominated by secondary forest of
Nothofagus species (N. obliqua and N. glauca) (Fagaceae)
and sclerophyllous species including Acacia caven (Mimosaceae),
Quillaja saponaria (Rosaceae), and Maytenus boaria (Celastraceae).
Also, many endangered tree species such as N. alessandri,
Pitavia punctata (Rutaceae) and Gomortega keule (Gomortegaceae)
occur in the study area. Anthropogenic disturbance is intense: in particular,
the region suffered massive forest clearance in the middle of the 20th
century for the cultivation of wheat crops, and non-sustainable extraction
of firewood in more recent decades. The area therefore currently is
characterized by a highly fragmented forest landscape.