Figure 2. Contour map of Western Ecuador. Both the western Andean
slopes and the much lower coastal Montañas de Mache appear. The isolated
foothill range, including Centinela ridge, found in southern Pichincha and
northern Los Ríos provinces, has been outlined with a box.
Figura 2. Mapa topográfico del Occidente del Ecuador. Se ve ambos las
faldas Andinas occidentales y a largo de la costa el más bajo Montañas de
Mache.
Deforestation and extant forests
Since World War II the Ecuadorian population has
nearly quadrupled from about three million to more than 12 million inhabitants
with the subsequent increase in demand for farmland. This demand in combination
with intensive road construction has resulted in colonization and extensive
deforestation throughout the coastal region (Dodson & Gentry 1991). Thus,
more than 95 % of the semi-deciduous and moist forests of the central and
southern parts of the coast forests have disappeared because the climates and
the soils of these areas are particularly suitable for intensive agriculture.
Today these fertile soils are used mostly for large-scale, export-oriented
production of bananas, cacao, and palm oil, rather than small-scale subsistence
farms. The drier deciduous forests are protected to some extent by an
unpredictable and scanty precipitation, but nearly all extant dry forests are
severely disturbed by grazing, firewood collection, charcoal production, lumber
extraction, annual burning, and subsistence agriculture.
Only in parts of Esmeraldas province and northern
Manabí do some tracts of moist forest remain, while only small patches persist
to the south. Apart from the established Sistema de Areas Protegidas the only
protected areas are small patches of forest such as the Río Palenque Science
Center [87 hectares] (Dodson & Gentry, 1978), Jauneche [130 hectares]
(Dodson et al. 1985), La Perla Forest [250 hectares] and the Reserva ENDESA [85
hectares]. Just 25 years ago there still remained much wet forest in western
Ecuador, but since then lumbering and road building have been particularly
devastating. Logging operations were followed by colonization which converted
large tracts of forest to farming and cattle raising. Numerous scattered palms,
however, still bear witness to the recent deforestation. What wet forest still
remains begins north of the Guayllabamba River, on the border between the
provinces of Pichincha and Imbabura, and stretches along the Andean foothills
northward through Imbabura, Esmeraldas and Carchi provinces
(Figure 3).
Much of these forests are in an ecological reserve protecting the eastern,
higher parts of the Cayapa River watershed, but wet forests also remain further
down-river mostly in areas reserved for the Cayapa indigenous peoples. Further
to the north on the Colombian border an established reserve, protecting the Awa
indigenous people, may protect most of the Ecuadorian pluvial forests, as well
as adjacent areas in Colombia, although a new road to the coast has facilitated
encroachment into the remaining wet and pluvial forests outside the reserve,
and very possibly also inside the reserve.
There now remains only one significant tract of humid
forest south of the Esmeraldas-Guayllabamba River-system
(Figure 3). In
1992 Conservation International reported the presence of ca. 200 km2
of very humid forests in the Montañas de Mache south of the town of Esmeraldas,
and the forest was rapidly being cut in from all sides. More recently CDC
[Centro de Datos para la Conservación] (1995) reported 400 km of extant forest
in this area. This forest has
since become known as Bilsa for the river (headwaters of Río Bilsa) from where
researchers first entered the area. Areas in Bilsa above ca. 500 m elevation are
covered with low-elevation cloud forest. Fortunately a considerable part of
this area has been purchased by the private conservation foundation "Jatun
Sacha", to establish the currently 3000 ha Bilsa Biological Reserve. In 1996 a
total of 70000 ha, including the Bilsa Biological Reserve, was included in the
newly established Mache-Chindul Ecological Reserve, which should end the
granting of timber concessions. However, the impact of colonists may not be
significantly reduced as most of the reserve area was already disturbed and
privately owned. Recently, too, a new road was completed on the western borders
of the Reserva Ecológica Mache-Chindul along the coast of Esmeraldas, which
will allow access for logging and colonization on the western side of the reserve.
The flora at Bilsa Biological Station and surrounding areas has been
intensively collected since 1994 (Clark 1997), and many species originally
known only from the Centinela Ridge or other recently destroyed low elevation
cloud forests, have been found to occur at the Bilsa Biological Reserve, as
well as some apparently endemic species. According to Parker & Carr (1992)
there also remain a few other low-elevation cloud forests in the coastal hills
further to the south of Bilsa, as well as along the Andean slopes. Relatively
few Gesneriaceae have been collected from these probably biologically diverse
and unique forests, and since the report by Parker & Carr (1992)
particularly the Andean slope forest remnants may have been destroyed.
[[figure filename="Figure3.jpg"
caption="Figure 3. Extant
forest vegetation in western lowland Ecuador according to satellite imaging.
Gray areas are those regions still covered with forest, while white areas have
been deforested (or never had forest). Due to the dense cloud-cover no
satellite-images were available of the very humid northeastern areas shaded
with a lighter gray, but these areas remain mostly forested. Note the 1000 m
contour line on the western Andean slopes.
Figura 3. Vegetación de bosque existente en el occidente bajo del Ecuador
de acuerdo a imagen satelital. Las áreas grises son regiones cubiertas aún con
bosque, mientras las zonas blancas han sido deforestadas (o que nunca han
tenido bosque). Debido a la presencia de muchas nubes no había imágen satélite
de zonas muy húmedas en el norte (mostrado con un gris mas claro), pero esas
áreas todavía son boscosas. Nota la línea de contorno de 1000 m en las faldas
andinas.
State of knowledge of western Ecuadorian
Gesneriaceae
There may occur ca. 1200 Gesneriaceae in the New
World, and the most species rich countries are Ecuador and Colombia with ca.
210 and 400 species, respectively (Skog & Kvist 1997; Kvist et al. 1998).
Panama although smaller is also extremely rich for its size with 150 species
(Skog 1979). The diversity of the Gesneriaceae generally correlates with
increasing precipitation and humidity, and the family is consequently
particularly abundant in northwestern Ecuador, western and northwestern
Colombia, and parts of Panama. The eastern Andean montane forests and adjacent
wet lowland forests also have many species of Gesneriaceae, but relatively few
species occur in Amazon forests away from the mountains.
Approximately 50 % and 75 % of the species of
Gesneriaceae found in Ecuador and Colombia (Kvist et al. 1998), respectively,
belong to genera that are poorly known so that species delimitation is
problematic. Fortunately, few taxonomic problems remain with the Gesneriaceae
distributed in the western lowland Ecuador, making it meaningful to analyze the
status and distribution of the species found in that region. The most speciose
genus in Ecuador,
Columnea with
approx. 60 epiphytic species, was recently extensively studied (Kvist &
Skog 1993; Smith 1994; Skog & Kvist 1994, 1998).
Gasteranthus represented by 26 terrestrial species in western
Ecuador, has just been revised (Skog & Kvist 2000), and the genera
Heppiella,
Cremosperma,
Reldia,
Kohleria, and
Pearcea have also been studied recently (Kvist 1990; Kvist & Skog 1988,
1989, 1992, 1996). Others of the larger and often problematic genera,
e.g.,
Alloplectus,
Drymonia, and
Paradrymonia are mostly represented by well-delimited species in
the region. The poorest understood genera in lowland western Ecuador may be
Besleria and
Monopyle, but these genera may comprise fewer than 10 species, and
Nautilocalyx, a particularly difficult genus in the Amazon basin,
does not occur in the region.
Results

A total of 109 species of Gesneriaceae have been
recorded from elevations below 1000 m in western Ecuador. Two commonly
cultivated but rarely collected species,
Episcia cupreata, and
Gloxinia perennis, are probably not native to the region, and have been
excluded from the analysis. This leaves 19 genera (of the 30 known from
Ecuador) and 107 species, with
Columnea,
Gasteranthus, and
Drymonia being the most speciose genera having 35, 15 and 14
species, respectively (Appendix A). A few of the 107 species, notably
Alloplectus ichthyoderma,
Columnea mastersonii,
Gasteranthus columbianus,
G.
lateralis, and
Heppiella ulmifolia, are very rare below 1000 m elevation, but common, at
least locally, at higher elevations in western Ecuador. Some of these species
may thus only disperse occasionally to lower elevations, rather than be
represented here with persistent populations. These latter species, however,
are included in the analysis presented in Appendix A. Here, the conservation
status of each of the 107 species native to western lowland Ecuador is
estimated (in the columns 2 and 3). Also included in Appendix A is information
on the geographical ranges of all 107 species (columns 4 to 7), the habitats of
each of these species (columns 8 to 10), identity of the species recorded from
nine western Ecuadorian forests (columns 1* to 9*), and which species are or
have been in cultivation (column 10*). The geographical locations of the nine
forests from where the Gesneriaceae have been recorded are indicated in Figure
1 (with the numbers 1 to 9), and Appendix B presents baseline data concerning
each of these nine forest localities and the study of their Gesneriaceae.
[[Tables 1 to 5