Figure legends
Figure 1: Hypothetical effects of potential land use on fish local
(alpha) diversity across elevation gradients. The solid curve represents
a decay of diversity with altitude. The lower dashed curve represents
potential diversity after natural lands are converted to agriculture and
other human uses, where greatest diversity loss (arrows) occurs at lower
altitude.
Figure 2: a) Geographical location of the sample sites. b) Examples of
the aquatic ecosystems within the altitudinal levels, which are the ones
recognized by van der Hammen and dos Santos (1995).
Figure 3. Comparisons of premontane and basimontane fish communities. a)
Rarefaction curves approach asymptotes, indicating representative
sampling. Premontane sites were inhabited by more species, as supported
by evidence in b) for total abundance, richness, and effective
diversity. c) Taxonomic composition differed between premontane and
basimontane sites, where Siluriformes were more prominent in basimontane
sites than in premontane sites. Characiformes were dominant in both site
types, but in different proportions. d) NMDS of fish communities from
the sampled sites. Dots represent pooled temporal data (2013-2022) for
sites. Polygons represent fish communities based on altitudinal levels
recognized by van der Hammen and dos Santos (1995).
Figure 4. Regression lines for species richness (a), total abundance
(b), and effective diversity (c) ~ altitude, where
regression lines represent GLMM predicted values and error bars. Note
log axes; regressions represent power law functions.
Data accessibility: Supporting data are available at
https://doi.org/10.5281/zenodo.10424407
Competing Interests Statement: All authors declare that there
are no competing interests.