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opencc-zeroSep 2020View details →

Thermal adaptations to extreme freeze-thaw cycles in the high tropical Andes

Temperature plays a key role in the biology of ectotherms, including anurans, which are found at higher elevations in the tropics than anywhere in the temperate zone. High-elevation tropical environments are characterized by extreme daily thermal fluctuation including high daily maxima and nightly freezing. Our study investigated the contrasting operative temperatures of the anurans Telmatobius marmoratus and Pleurodema marmoratum in different environmental contexts at the same elevation and biome above 5200 meters. Telmatobius marmoratus avoids extremes of daily temperature fluctuation by utilizing thermally buffered aquatic habitat at all life stages, with minimal operative temperature variation (range: 4.6–8.0°C). Pleurodema marmoratum, in contrast, experienced operative temperatures from -3.5 to 44°C and has one of the widest thermal breadths reported for any tropical frog, from >32°C (critical thermal maximum) to surviving freezing periods of 1 hr and 6 hr down to -3.0°C. Our findings expand experimental evidence of frost tolerance in amphibians to the widespread Neotropical family Leptodactylidae, the first such evidence of frost tolerance in a tropical amphibian. Our study identifies three strategies (wide thermal tolerance breadth, use of buffered microhabitats, and behavioral thermoregulation), which allow these tropical frogs to withstand the current wide daily thermal fluctuation above 5000 masl and which may help them adapt to future climatic changes.

opencc-zeroOct 2020View details →

Thermal niche traits of high alpine plant species and communities across the tropical Andes and their vulnerability to global warming

<a name="_Hlk10643461">Aim</a> The Climate Variability Hypothesis (CVH) predicts that locations with reduced seasonal temperature variation select for species with narrower thermal ranges. Here we (1) test the CVH by assessing the effect of latitude and elevation on the thermal ranges of Andean vascular plant species and communities, and (2) assess tropical alpine plants vulnerability to warming based on their thermal traits. Location Tropical Andes Taxon Vascular plants Methods Temperature data for 505 vascular plant species from alpine communities on 49 summits, were extracted from 29,627 geo-referenced occurrences. Species thermal niche traits (TNTs) were estimated using bootstrapping for: minimum temperature, optimum (mean) temperature, and breadth (maximum-minimum). Plant community-weighted scores were estimated using the TNTs of their constituent species. CVH was tested for species, biogeographic species groups and communities. Vulnerability to global warming was assessed for species, biogeographic species groups and communities. Results Species restricted to the equator showed narrower thermal niche breadth than species whose ranges stretch far from the equator, however, no difference in niche breadth was found across summits' elevation. Biogeographic species groups distributed close to the equator and restricted to alpine regions showed narrower niche breadth than those with broader ranges. Community weighted-scores of thermal niche breadth were positively related to distance from equator but not to elevation. Based on their TNTs, species restricted to equatorial latitudes and plant communities dominated by these species were identified as the most vulnerable to the projected 1.5 °C warming, due to a potentially higher risk of losing thermal niche space. Main conclusions Our study confirms that the CVH applies to high tropical Andean plant species and communities, where latitude had a strong effect on the thermal niche breadth. TNTs are identified as suitable indicators of species' vulnerability to warming and are suggested to be included in long-term biodiversity monitoring in the Andes.

opencc-zeroDec 2016View details →

Data from: Rapid diversification and time explain amphibian richness at different scales in the Tropical Andes, Earth's most biodiverse hotspot

The Tropical Andes are Earth's most species-rich biodiversity hotspot for both animals and plants. Nevertheless, the ecological and evolutionary processes underlying this extraordinary richness remain uncertain. Here, we examine the processes that generate high richness in the Andes relative to other regions in South America, and across different elevations within the Andes, using frogs as a model system. We combine distributional data, a newly generated time-calibrated phylogeny for 2318 frog species, and phylogenetic comparative methods to test the relative importance of diversification rates and colonization times for explaining Andean diversity at different scales. At larger scales (among regions and families), we find that faster diversification rates in Andean clades most likely explain high Andean richness. In contrast, at smaller temporal and spatial scales (within family-level clades, within the Andes), diversification rates rarely explain richness patterns. Instead, we show that colonization times are important for shaping elevational richness patterns within the Andes, with more species found in habitats colonized earlier. We suggest that these scale-dependent patterns might apply to many other richness gradients. Recognition of this scale-dependence may help to reconcile conflicting results among studies of richness patterns across habitats, regions, and organisms.

opennotspecifiedDec 2011View details →

FIGURE 3 in A brief revision of brachypterous Phaneropterinae of the tropical Andes (Orthoptera, Tettigoniidae, Odonturini)

FIGURE 3. Nanoleptopoda albifrons sp. nov.: female alive (second specimen), and frontal view, subgenital plate, and lateral

opennotspecifiedDec 2011View details →

FIGURE 2 in A brief revision of brachypterous Phaneropterinae of the tropical Andes (Orthoptera, Tettigoniidae, Odonturini)

FIGURE 2. Nanoleptopoda nigrifrons sp. nov.: female allotype. Alive, and lateral and dorsal view of specimen, face, and subgenital plate.

opennotspecifiedDec 2011View details →

FIGURE 1 in A brief revision of brachypterous Phaneropterinae of the tropical Andes (Orthoptera, Tettigoniidae, Odonturini)

FIGURE 1. Nanoleptopoda nigrifrons sp. nov.: male holotype. Oscillograms of call fragment (complete call duration 10–15 s) and one expanded syllable; linear power spectrum of frequency range; specimen in lateral and dorsal view, subgenital plate and cerci in ventral view, and cerci in dorsal view.

FIGURE 7 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 7. Distribution of five species of Riama in Ecuador. These species form a clade sister to R. unicolor (see Fig. 8).

FIGURE 1 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 1. Holotype of Riama yumborum sp. nov. (QCAZ 10827, male) in dorsal (left) and ventral (right) views. Scale bar = 5 mm. Photographs by D. A. Paucar.

FIGURE 5 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 5. Close-up of dorsum of holotype of Riama yumborum sp. nov. (QCAZ 10827, male). Photograph by D. A. Paucar.

FIGURE 3 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 3. Ventral view of pelvic region showing cloacal plate of Riama yumborum. Left: QCAZ 10827, male, holotype; right: QCAZ 10822, female paratype. Photographs by D. A. Paucar.

FIGURE 8 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 8. Majority rule (50%) consensus tree of 18,000 trees obtained from a Bayesian analysis of three mitochondrial (12s, 16s, nd4) and one nuclear gene (c-mos) from 26 specimens. Numbers next to branches correspond to posterior probability values (asterisks indicate values> 0.99). For sequences generated in this study, voucher museum numbers followed by locality of collection are indicated for each terminal.

FIGURE 6 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 6. Paratype of Riama yumborum sp. nov. (QCAZ 10822, female) in dorsal (top) and ventral (bottom) views. Photographs by L. Bustamante.

FIGURE 4 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 4. Left hemipenis of Riama yumborum sp. nov. (QCAZ 11079) in sulcate (left), lateral (middle), and asulcate (right) views. Scale bar = 1 mm. Photographs by P. Nunes.

FIGURE 2 in A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

FIGURE 2. Head of holotype of Riama yumborum sp. nov. (QCAZ 10827, male) in dorsal (top), ventral (middle), and lateral (bottom) views. Scale bar = 5 mm. Photographs by D. A. Paucar.

opencc-zeroDec 2018View details →

Data from: The influence of historical dispersal on the phylogenetic structure of tree communities in the tropical Andes

We test for evidence of the Tropical Niche Conservatism or the Out of The Tropics hypotheses in structuring patterns of tree community composition along a 2000+ meter elevational gradient in the northern tropical Andes. By collecting and integrating data on the presence-absence of tree species within plots with phylogenetic information, we analyzed: 1) patterns of phylogenetic dispersion and species diversity along the elevational gradient based on indexes of net relatedness, nearest taxon relatedness, and species richness (α-diversity); and 2) the replacement of lineages along the gradient using the PhyloSorensen metric (β-diversity). More specifically, we established 20 0.25-ha permanent tree inventory plots between 750 and 2802 m asl where all individuals with Diameter at Breast Height (DBH) ≥ 10 cm were measured and identified. We then used a series of linear models to test for changes in α and β diversity between plots in relation to elevation. Neither the net relatedness index nor the nearest taxon index showed a significant relationship with elevation. However, there was greater phylogenetic over-dispersion at intermediate elevations; this likely reflects the mixing of species with contrasting origins from tropical and temperate lineages. β-diversity between plots was negatively related to the corresponding difference in elevation, indicating that closely related lineages occupy similar ranges of elevation and temperature. We conclude that the immigration of lineages from extra-tropical regions have significant effects in determining the phylogenetic structure of tree communities in tropical Andean forests.

opennotspecifiedJun 2024View details →

FIGURE 3. Radula longicarinata. A. Marginal leaf cells. B. Median leaf cells. C. Basal leaf cells. D. Habit with gynoecia. E. Habit. F. Leaves. G in High liverwort diversity in the tropical Andes as evidenced by the discovery of three new species of Radula (Radulaceae)

FIGURE 3. Radula longicarinata. A. Marginal leaf cells. B. Median leaf cells. C. Basal leaf cells. D. Habit with gynoecia. E. Habit. F. Leaves. G. Cross section of stem. H. Cladographs of plants (U = gynoecia without perianth) (A-C, G = 50 µm, D-F = 500 µm; All from the holotype).