262
J.J. Armesto et al.
the latter. This hypothesis can be tested by examining the reproductive
success of hummingbird-pollinated species whose flowering period overlaps with that of Eucalyptus . Since many hummingbird-pollinated plants
are canopy dwellers, it is possible that a decline of these populations
cannot be readily detected. Studies of the dynamics of these canopy
species could be very useful in detecting future trends.
It is apparent that future expansions of the grasslands at the expense of
the native forest area or plans for large-scale substitution of native forests
by exotic tree plantations should have negative effects on the species that
integrate the mutualistic guilds described here. Because of its isolation
from other forested areas and its species-poor avifauna, the temperate
rainforest of the Pacific coast of South America must be perceived as an
islandlike ecosystem, where species losses are unlikely to be compensated
by immigration from contiguous forest habitats or by increases in the
populations of other ecologically similar species.
Acknowledgments. Data collection in Chiloe has been funded by
Fondecyt , Grants 860-88 and 1135-92, and by the Universidad de Chile.
The paper was written under the sponsorship of Grant 1135-92 from
Fondecyt, Chile. Peter Feinsinger , Douglas J. Levey, Steward T.A.
Pickett , and Mary F. Willson provided critical and helpful reviews of
earlier versions.
References
Alaback , P.B. 1991. Comparative ecology of temperate rainforests of the
Americas along analogous climatic gradients. Rev Chi! Hist Nat, 64, 399-412.
Arizmendi , M. del C., and Ornelas, J.F. 1990. Hummingbirds and their floral
resources in a tropical dry forest in Mexico. Biotropica, 22, 172-180.
Armesto , J.J ., and Figueroa, J. 1987. Stand structure and dynamics in the
temperate rainforests of Chiloe archipelago , Chile. J Biogeog, 14,367-376.
Armesto, J.J ., and Fuentes, E.R. 1988. Tree species regeneration in a midelevation, temperate rain forest in Isla de Chiloe, Chile. Vegetatio, 74, 55-78.
Armesto , J.J ., and Rozzi, R. 1989. Seed dispersal syndromes in the rain forest of
Chiloe: Evidence for the importance of biotic dispersal in a temperate rain
forest. J Biogeog , 16,219-226.
Armesto, J.J ., Rozzi, R., Miranda, P., and Sabag, C. 1987. Plant/frugivore
interactions in South American temperate forest. Rev Chi! Hist Nat, 60,
321-336.
Armesto , J.J. , Smith-Ramfrez, C., Le6n P., and Arroyo, M.K. 1992. Biodiversidad y conservaci6n del bosque templado en Chile. Amb Des (Chile), 8,
19-24.
Arroyo, M.T.K ., Armesto, J.J., Squeo , F., and Gutierrez, J. 1993. Global change:
Flora and vegetation of Chile. In H.A. Mooney, E.R . Fuentes , and B.!.
Kronberg (eds.), Earth System Responses to Global Change: Contrasts Between
North and South America (pp. 239-263) . San Diego: Academic Press.
Bolger, D.T., Alberts, A .C., and Soule, M.E. 1991. Occurrence patterns of birds
species in habitat fragments, sampling, extinction, and nested species subsets.
Am Nat , 137, 155-166.
J.J. Armesto et al.
the latter. This hypothesis can be tested by examining the reproductive
success of hummingbird-pollinated species whose flowering period overlaps with that of Eucalyptus . Since many hummingbird-pollinated plants
are canopy dwellers, it is possible that a decline of these populations
cannot be readily detected. Studies of the dynamics of these canopy
species could be very useful in detecting future trends.
It is apparent that future expansions of the grasslands at the expense of
the native forest area or plans for large-scale substitution of native forests
by exotic tree plantations should have negative effects on the species that
integrate the mutualistic guilds described here. Because of its isolation
from other forested areas and its species-poor avifauna, the temperate
rainforest of the Pacific coast of South America must be perceived as an
islandlike ecosystem, where species losses are unlikely to be compensated
by immigration from contiguous forest habitats or by increases in the
populations of other ecologically similar species.
Acknowledgments. Data collection in Chiloe has been funded by
Fondecyt , Grants 860-88 and 1135-92, and by the Universidad de Chile.
The paper was written under the sponsorship of Grant 1135-92 from
Fondecyt, Chile. Peter Feinsinger , Douglas J. Levey, Steward T.A.
Pickett , and Mary F. Willson provided critical and helpful reviews of
earlier versions.
References
Alaback , P.B. 1991. Comparative ecology of temperate rainforests of the
Americas along analogous climatic gradients. Rev Chi! Hist Nat, 64, 399-412.
Arizmendi , M. del C., and Ornelas, J.F. 1990. Hummingbirds and their floral
resources in a tropical dry forest in Mexico. Biotropica, 22, 172-180.
Armesto , J.J ., and Figueroa, J. 1987. Stand structure and dynamics in the
temperate rainforests of Chiloe archipelago , Chile. J Biogeog, 14,367-376.
Armesto, J.J ., and Fuentes, E.R. 1988. Tree species regeneration in a midelevation, temperate rain forest in Isla de Chiloe, Chile. Vegetatio, 74, 55-78.
Armesto , J.J ., and Rozzi, R. 1989. Seed dispersal syndromes in the rain forest of
Chiloe: Evidence for the importance of biotic dispersal in a temperate rain
forest. J Biogeog , 16,219-226.
Armesto, J.J ., Rozzi, R., Miranda, P., and Sabag, C. 1987. Plant/frugivore
interactions in South American temperate forest. Rev Chi! Hist Nat, 60,
321-336.
Armesto , J.J. , Smith-Ramfrez, C., Le6n P., and Arroyo, M.K. 1992. Biodiversidad y conservaci6n del bosque templado en Chile. Amb Des (Chile), 8,
19-24.
Arroyo, M.T.K ., Armesto, J.J., Squeo , F., and Gutierrez, J. 1993. Global change:
Flora and vegetation of Chile. In H.A. Mooney, E.R . Fuentes , and B.!.
Kronberg (eds.), Earth System Responses to Global Change: Contrasts Between
North and South America (pp. 239-263) . San Diego: Academic Press.
Bolger, D.T., Alberts, A .C., and Soule, M.E. 1991. Occurrence patterns of birds
species in habitat fragments, sampling, extinction, and nested species subsets.
Am Nat , 137, 155-166.