The bat fauna of Tambito, Colombia

Abstract

This paper summarizes a first account of the bat fauna in the middle elevations of the Tambito Nature Reserve in the Colombian Chocó. A month-long survey using mist netting found 13 genera comprising at least 26 species. As expected from mist net bias, virtually all the bats captured were understory phyllostomids, with few exceptions. Nonetheless, high ecological diversity was confirmed with frugivorous, nectarivorous, insectivorous and sanguivorous guilds represented. Estimates using extrapolation place the real understory diversity somewhere above 30 species, making this a key site for conservation of bats in general, and the genera Sturnira, Platyrrhinus, and Vampyressa, in particular.

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the bats captured were understory phyllostomids, with
few exceptions. Nonetheless, high ecological diversity
was confirmed with frugivorous, nectarivorous,
insectivorous and sanguivorous guilds represented.
Estimates using extrapolation place the real understory
diversity somewhere above 30 species, making this a
key site for conservation of bats in general, and the
genera Sturnira, Platyrrhinus, and Vampyressa, in
particular.
INTRODUCTION
Studies in New World tropics are only now beginning
to assess the true diversity of Neotropical bats, but
sampling has been confined to a handful of well-
documented sites where research stations happen to
be located (Voss & Emmons 1996, Simmons & Voss
1998). This approach has left unexamined vast areas of
Neotropical forests, for which there are very few
comprehensive mammalian inventories. One such
critical information gap corresponds to the Colombian
Chocó (Voss & Emmons 1996). Based on its high
endemism and threats from human disturbance, the
Chocó tropical rainforest has been identified as a global
biodiversity hotspot (Olson & Dinerstein 1996).
Early mammal collections from the Pacific slopes of the
West Andes in Cauca list no bats for the nearby locality
of El Cocal, at 1200 m elevation (Allen 1916). Collections
by Kjell von Sneidern in the 1930s at five localities in
west Cauca left a gap in elevation between 900 and
1700 meters (Tamsitt and Valdivieso 1966). Modern bat
surveys in southwest Colombia have been spotty, with
only a handful of noteworthy records resulting in
publication (e.g., Alberico 1987, 1994). The picture that
emerges from these previous works is still fragmentary.
So far, the only sustained effort to inventory the middle
elevation bat faunas of the Chocó has taken place in
Nariño (south of Cauca, bordering Ecuador) at Reserva
Natural La Planada, 1,525 m elevation (Ospina-Ante &
Gómez 1995). Our survey lays the ground work for
future in-depth study of a montane bat fauna from the
middle elevations of the Pacific slopes of the West
Andes in Cauca, Colombia.
METHODS AND MATERIALS
Field Locality
Tambito Nature Reserve is located 50 km west of
Popayán on the Pacific slope of the Cordillera
Occidental, Cauca, Colombia, at 02°30’N 77°00’W. It is
adjacent to Parque Nacional Natural (PNN) Munchique,
and encompasses c. 3,000 ha. of very humid , both
premontane and lower montane forest, at 1,050–2,800
m. The yearly rainfall varies from 3,800mm to 7,000mm,
increasing with altitude. A seven-year rainfall record
from Tambito indicates a bimodal seasonality with
THE BAT FAUNA OF TAMBITO, COLOMBIA
Liliana M. Dávalos
Graduate Fellow - Department of Mammalogy,
American Museum of Natural History
Central Park West at 79th Street
New York, New York 10024-5192 USA
davalos@amnh.org
Jimmy A. Guerrero
Monitor de la Colección - Museo de Historia Natural,
Universidad del Cauca
Cra. 1ra No. 1A-27, Barrio Caldas
Popayán, Colombia
guerrero@ucauca.edu.co
ABSTRACT
This paper summarizes a first account of the bat fauna
in the middle elevations of the Tambito Nature Reserve
in the Colombian Chocó. A month-long survey using
mist netting found 13 genera comprising at least 26
species. As expected from mist net bias, virtually all

Chiroptera Neotropical, 5(1-2), 1999
Page 113
October/November and February/March being the
wettest months. The summer represents the dry season,
with high sensitivity to El Niño and La Niña. In 1997 (a
strong El Niño year), just 20mm of rain fell in the 3
months from June to September. Average temperatures
range from 13ºC to 19ºC depending on altitude. Relative
humidity is above 90% for much of the day (Jarvis &
Dávalos 1999).
The topography of Tambito is extremely complex. The
slopes are steep, being as high as 60 degrees in places,
with a great deal of spatial complexity on a small scale.
Epiphytic mosses characterize the physical appearance
of the forest in the upper reaches of the catchment and
in the more humid localities. Netting sites were selected
on the bases of accessibility from the cabin, diversity
of microhabitats, and striving to maintain sampling at
the same elevation, c. 1,500m.
METHODS
Ground-level (0-3 m) mist-netting and specimen
preparation followed standard methods described in
Simmons & Voss (1998) and Handley (1988)
respectively. Each captured bat was identified in the
field using Emmons (1997), Reid (1998), and Koopman
(1994). We also used unpublished dichotomous keys
for bats of the Chocó kindly facilitated by Drs. C.O.
Handley (Smithsonian Institution, Washington, D.C.)
and M.S. Alberico (Universidad del Valle, Cali).
Following Voss & Emmons (1996) vouchers of all
species encountered were preserved to document
identification. We collected liver tissue from each
specimen for DNA studies, prior to immersion in
formaldehyde. Conspicuous ectoparasites were also
collected. The specimen collection resulting from our
study was deposited at the Museo de Ciencias
Naturales, Universidad del Cauca (Popayán, Cauca).
Tissue samples and parasites were deposited at the
Molecular Laboratory of Instituto Alexander Von
Humboldt (Cali, Colombia).
RESULTS
In 24 nights of netting we captured 90 bats of 13 genera.
A definitive account, comprising at least 26 species
recorded is in progress (Dávalos & Guerrero in prep.).
All, except one (Myotis), of the 13 genera recorded
were Phyllostomids.
Taxonomic account
The preliminary taxonomic list resulting from our
sampling is summarized in Table 1.
Community ecology
A summary of relative capture abundance for different
diet-based guilds is presented in Table 2. As expected
from our sampling bias, most captured bats
(stenodermatines and carolliines) correspond to the
under-story frugivore guild. Size varies greatly among
the frugivores from large, e.g., Platyrrhinus, to medium,
e.g., Sturnira and Carollia, to small, e.g., Vampyressa.
Insectivores also show great size variation from tiny,
e.g. Myotis, to medium-large, e.g. Lonchorhina, but
size variation among nectarivores was almost null.
Genus Species (or number of species) Microhabitat
Desmodus rotundus Secondary
Phyllostomus 2Primary
Mimon crenulatum Edge
Lonchorhina aurita Secondary
Lonchophylla robusta Secondary, edge
Anoura 2Primary, secondary, edge
Carollia 2Primary, secondary
Sturnira 5Secondary, edge, stream
Platyrrhinus 3Primary, secondary, edge
Vampyressa 2Secondary, edge
Enchisthenes hartii Edge
Artibeus (Dermanura)2Primary, secondary
Myotis 3Secondary, edge
Table 1. Bats sampled at Tambito
Diet-based guild Number captures Percent captures
Frugivore 71 76.3%
Insectivore 11 12.0%
Nectarivore 88.6%
Sanguivore 11.1%
Table 2. Relative abundance in captures for different bat guilds

Chiroptera Neotropical, 5(1-2), 1999
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DISCUSSION
Pending definitive identification, the bat species
richness recorded at Tambito is relatively high, when
compared with sites of similar elevation in the Andes.
For the middle elevations of Nariño, 12 species have
been definitely recognized by Cadena et al. (1998), five
of which are also reported by Ospina-Ante & Gómez
(1995) in their species list that rises to 20. The results
of the latter, however, are inconclusive, as their
taxonomic account is still being revised (L.G. Gómez
pers. comm.).
Even with the limitations inherent to mist-net sampling
(Remsen & Good 1996), there was no sign of saturation
in capture for our survey (Figure 1) and the number
and range size of species suggests a rich and
ecologically diverse understory bat community.
Although estimation by extrapolation from capture data
is still in its infancy (Colwell & Coddington 1994), the
use of parametric and non-parametric estimators
indicate that real understory richness would be
somewhere between 30 and 45 species as seen in Figure
1.
Because mist netting was the only method used and it
is known to bypass most (if not all) aerial insectivores
(Simmons et al. 1998), the overall bat richness in
Tambito may be substantially higher. This, and the fact
that several Chocoan species of genera found in
Tambito (Sturnira, Platyrrhinus, Vampyressa) are
listed as near threatened or threatened by the IUCN
(IUCN 1996) confirm the reserve’s status as a key site
for the conservation of flying vertebrates (Donegan &
Dávalos 1999).
For conservation purposes, further bat inventories
using other methods e.g., ultrasound recording, will
allow more comprehensive study of the community,
especially since all modern surveys have used mist
netting protocols similar to our own. Additionally,
research in basic ecology and natural history of virtually
all the bats recorded is indispensable, as these basic
data are still unknown. There are, to our knowledge,
no published studies documenting specific foraging
behavior of bats in cloud forests of the Colombian
Chocó. Extensive work over several decades on Barro
Colorado Island, Panama, has shown fine-grain
partition of resources in the lowland bat community
(Kalko et al. 1996), similar efforts are necessary to
characterize rich chiropteran communities of higher
elevations.
ACKNOWLEDGEMENTS
Fieldwork for this survey was sponsored by the Royal
Geographic Society, Bat Conservation International,
the Institute for Latin American and Iberian Studies
and the Center for Environmental Research and
Conservation at Columbia University, and the
Figure 1. Parametric and non-parametric estimation by extrapolation from limited capture data. Observed captures
randomized 100 times are in black dots with error bars, adjusted Michaelis-Menten curve in black with maximum-
likelihood upper-boundary in squares, non-parametric estimators: jackknife and Chao’s in crosses and triangles,
respectively.

Chiroptera Neotropical, 5(1-2), 1999
Page 115
Explorers’ Club. Dr. Nancy B. Simmons provided
countless letters of recommendation and scientific
advice. Dr M. Mulligan and his HERB project at King’s
College London, the Museo de Historia Natural and
Fundación Proselva in Popayán facilitated logistics.
Many thanks to Q. Lame, Olga, L. González and A.
Bernal at the Tambito cabin. S. Reddy wrote the
programs for data analyses. This paper is dedicated to
the late A.J. Negret.
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