Nutritional evaluation of three underexploited andean tubers:Oxalis tuberosa (Oxalidaceae),Ullucus tuberosus (Basellaceae), andTropaeolum tuberosum (Tropaeolaceae)

Three species of edible tubers endemic to and domesticated in the Andes were studied for their nutritional value. Collected samples ofOxalis tuberosa, Ullucus tuberosus, andTropaeolum tuberosum show a high amount of variation in both percent protein and quality of essential amino acids. A protein difference of120% is present amongT. tuberosum cultivars and a protein difference of 300% is present among the three species. The data indicate that previous published Andean tuber crop food values may need revision. The introduction of "improved" crop varieties and less nutritious foodstuffs threatens the base ofcultivar diversity that has been selected by Andean agriculturists over centuries. This rapid erosion of Andean tuber diversity indicates the importance of identifying and conserving Andean tuber cul-tivars throughout the Andes.     

Suitability of AFLP markers for the study of genomic relationships within theOxalis tuberosa alliance

O. tuberosa is an Andean crop that belongs to the worldwide distributed genusOxalis. On the basis of their chromosome numbers the following species (O. herrerae, O. lotoides, O. medicaginea, O. mollissima, O. oblongiformis, O. peduncularis, O. spiralis, O. subintegra, O. tabaconanensis, O. tuberosa, O. villosula) were placed in an alliance. To analyse five species belonging to theOxalis tuberosa alliance (O. oblongiformis, O. peduncularis, O. tabaconanensis, O. tuberosa andO. villosula) and a distant member of the genus (O. articulata), we examined 253 AFLP markers generated after amplification using four primer combinations. Within the alliance, two main clusters were observed, one containing the diploid species and the other group with the polyploid speciesO. tuberosa. All of the primer combinations assayed showed the same clustering pattern. Grouping of accessions of each species by data analysis corresponded largely with their previous taxonomic classifications. The concordance between the clustering of the individuals belonging to different species obtained in this work show the appropriateness of AFLP markers for this type of study. The results obtained are in good agreement with the cytogenetic hypothesis and showed a clustering behaviour, which is similar to the one previously obtained using ITS rDNA nucleotide sequence comparison.     

Chromosome number of theOxalis tuberosa alliance (Oxalidaceae)

Twelve taxa of theOxalis tuberosa alliance were analysed and found to share the same basic chromosome number x = 8. The karyotypes are composed by small metacentric and submetacentric chromosomes. Different ploidy levels were found among the taxa: there were 9 diploids, 1 tetraploid, 1 hexaploid and 1 octoploid. The last ploidy level corresponds toO. tuberosa, the only tuber bearing taxon found so far in the alliance. Cytotaxonomic evidence and evolutionary considerations suggest to classify theO. tuberosa alliance in sect.Herrerea.     

Ploidy levels among species in the 'Oxalis tuberosa alliance' as inferred by flow cytometry

The 'Oxalis tuberosa alliance' is a group of Andean Oxalis species allied to the Andean tuber crop O. tuberosa Molina (Oxalidaceae), commonly known as 'oca'. As part of a larger project studying the origins of polyploidy and domestication of cultivated oca, flow cytometry was used to survey DNA ploidy levels among Bolivian and Peruvian accessions of alliance members. In addition, this study provided a first assessment of C-values in the alliance by estimating nuclear DNA contents of these accessions using chicken erythrocytes as internal standard. Ten Bolivian accessions of cultivated O. tuberosa were confirmed to be octoploid, with a mean nuclear DNA content of approx. 3.6 pg/2C. Two Peruvian wild Oxalis species, O. phaeotricha and O. picchensis, were inferred to be tetraploid (both with approx. 1.67 pg/2C), the latter being one of the putative progenitors of O. tuberosa identified by chloroplast-expressed glutamine synthetase data in prior work. The remaining accessions (from 78 populations provisionally identified as 35 species) were DNA diploid, with nuclear DNA contents varying from 0.79 to 1.34 pg/2C.     

Three new species and a revised key to species of Oxalis section Polymorphae (Oxalidaceae)

Three new species of Oxalis sect. Polymorphae are here described and illustrated: Oxalis artemioides, O. calcicola, and O. monochasiata. These species have narrow geographic distributions, each being known from just one location. Oxalis artemioides differs from other species of the section by the glabrous stem, narrow terminal leaflets (8–10.5 × 2 mm), and inflorescences with elongated dichasial branches bearing flowers only in the distal portion. Oxalis calcicola differs from other species by having the young stem with adpressed-retrorse trichomes, inflorescences shorter than adjacent leaves, short dichasial branches (0.5–3 mm long) with flowers densely grouped along the entire length, and glabrous pedicels. Oxalis monochasiata is remarkable because of its monochasial inflorescence and the two-ovulate carpels, both features unique within Oxalis sect. Polymorphae. The new species are compared to similar species of the section, and information on distribution and habitat, phenology, and conservation status according with IUCN criteria are provided. Geographic distribution maps, lists of examined materials and an identification key for species of this section are also presented.     

Description of Thecavermiculatus andinus n.sp. (Meloidoderidae), a Round Cystoid Nematode from the Andes Mountains of Peru

Thecavermiculatus andinus n.sp. is described and illustrated from Oxalis tuberosa originally collected in the vicinity of Lake Titicaca high in the Andes mountains of southern Peru. This new species differs markedly front the other two species in the genus, especially in having a much greater female vulval-anal distance and annules with lined punctation on most of the female body with a lacelike pattern restricted to the posterior portion, particularly at the vulva and anus which do not protrude. Females are essentially spherical with protruding neck, white to yellowish in color, and can easily be mistaken for potato cyst nematodes. Among the dozen or more known weed and crop host plants are potato and eggplant. In order to accommodate this new species, the genus Thecavermieulatus is emended. A key to the species of this genus is presented.     

Phytogeographical relations of the Andean dry valleys of Bolivia

Aim The objective of this study is to examine the phytogeographical affinities of the Andean dry valleys of Bolivia in order to contribute to a better understanding of the Andean dry flora's distribution, origin and diversity. Particular emphasis is given to the analysis of the floristic connections of this flora with more austral parts of South America. Location The dry valleys of Bolivia are located in the Andes of the southern half of the country, at elevations between 1300 and 3200 m. Methods An extensive floristic list compiled by the author to evaluate plant diversity in these Andean regions was used as the base for this study. To accomplish this, all recorded genera and species were assigned, respectively, to 11 and 12 phytogeographical elements established previously by the author. Two phytogeographical spectra were thus obtained and analysed. Results At the genus level, the Andean dry valleys of Bolivia are clearly dominated by genera that have widespread distributions (cosmoplitan and subtropical genera). Many of these reached the Andes from the lowland region of the Chaco. At species level, Andean elements constitute more than 60% of the species total, most of which are restricted to the central‐southern Andes. This suggests that Chaco‐related and Andean genera had considerable levels of speciation in these valleys. Many genera and more than half the species have their northernmost distribution in the dry valleys of Bolivia, thereby underlining strong relationships with central‐southern South America (mainly Argentina, Paraguay and southern Brazil). The data supports the belief of the existence, in central‐southern Peru, of a floristic disjunction in dry to arid environments that separates a tropical dry flora north of this limit from a dry subtropical/warm temperate flora south of it. Main conclusions The Andean dry valleys of Bolivia are diverse plant communities with high levels of endemism (c. 18% of the species). The species of this region are more related to those present in central‐southern South America than to the flora of northern South America that ranges southwards to Peru. Many of the species have restricted distributions in the dry Andes of Bolivia and Argentina, and many genera of these dry valleys have their northernmost distribution in Bolivia/southern Peru, too. The data point to high levels of speciation also in the central Andes.     

Explaining Andean megadiversity: the evolutionary and ecological causes of glassfrog elevational richness patterns

The Tropical Andes are an important global biodiversity hotspot, harbouring extraordinarily high richness and endemism. Although elevational richness and speciation have been studied independently in some Andean groups, the evolutionary and ecological processes that explain elevational richness patterns in the Andes have not been analysed together. Herein, we elucidate the processes underlying Andean richness patterns using glassfrogs (Centrolenidae) as a model system. Glassfrogs show the widespread mid‐elevation diversity peak for both local and regional richness. Remarkably, these patterns are explained by greater time (montane museum) rather than faster speciation at mid‐elevations (montane species pump), despite the recency of the major Andean uplift. We also show for the first time that rates of climatic‐niche evolution and elevational change are related, supporting the hypothesis that climatic‐niche conservatism decelerates species' shifts in elevational distributions and underlies the mid‐elevation richness peak. These results may be relevant to other Andean clades and montane systems globally.     

Origins of domestication and polyploidy in oca (Oxalis Tuberosa: Oxalidaceae). 2. Chloroplast-expressed glutamine synthetase data

In continuing study of the origins of the octoploid tuber crop oca, Oxalis tuberosa Molina, we used phylogenetic analysis of DNA sequences of the chloroplast-active (nuclear encoded) isozyme of glutamine synthetase (ncpGS) from cultivated oca, its allies in the "Oxalis tuberosa alliance," and other Andean Oxalis. Multiple ncpGS sequences found within individuals of both the cultigen and a yet unnamed wild tuber-bearing taxon of Bolivia were separated by molecular cloning, but some cloned sequences appeared to be artifacts of polymerase chain reaction (PCR) recombination and/or Taq error. Nonetheless, three classes of nonrecombinant sequences each joined a different part of the O. tuberosa alliance clade on the ncpGS gene tree. Octoploid oca shares two sequence classes with the Bolivian tuber-bearing taxon (of unknown ploidy level). Fixed heterozygosity of these two sequence classes in all ocas sampled suggests that they represent homeologous loci and that oca is allopolyploid. A third sequence class, found in eight of nine oca plants sampled, might represent a third homeologous locus, suggesting that oca may be autoallopolyploid, and is shared with another wild tuber-bearing species, tetraploid O. picchensis of southern Peru. Thus, ncpGS data identify these two taxa as the best candidates as progenitors of cultivated oca.     

Rapid and Recent World-Wide Diversification of Bluegrasses (Poa,Poaceae) and Related Genera

Rapid species diversifications provide fascinating insight into the development of biodiversity in time and space. Most biological radiations studied to date, for example that of cichlid fishes or Andean lupines, are confined to isolated geographical areas like lakes, islands or island-like regions. Using DNA sequence data of the ribosomal internal transcribed spacer (ITS) for many species of the Poa alliance, a group comprising about 775 C₃ grass species, revealed rapid and parallel diversifications in various parts of the world. Some of these radiations are restricted to isolated areas like the Andes, whereas others are typical of the lowlands of mainly the northern hemisphere. These radiations thus are not restricted to island-like areas and are seemingly actively ongoing. The ages of the diversifying clades are estimated to be 2.5–0.23 million years (Myr). Conservative diversification rates in the Poa alliance amount to 0.89–3.14 species per Myr, thus are in the order of, or even exceeding, other instances of well-known radiations. The grass radiations of the mainly cold-adapted Poa alliance coincide with the Late Tertiary global cooling, which resulted in the retreat of forests and the subsequent formation of cold-adapted grasslands especially in the northern, but also in parts of the southern hemisphere. The cold tolerance, suggested to be one of the ecological key innovations, may have been acquired during the early diversification of the subfamily Pooideae, but became significant millions of years later during the Pliocene/Pleistocene radiation of the Poa alliance.     

Vegetation in a high Andean transect between Turi and Cerro León in Northern Chile

This paper reports the results of a phytosociological and gradient analysis of the vegetation occurring along an altitudinal gradient from Turi (3100 m) to Cerro León (4250 m) on the western flank of the Andes in northern Chile (22°06′–22°22′ S; 68°15′–68°07′ W). Along the transect, the total cover of vegetation ranges from 2.5% at the lower end to 35.7% at 4000 m altitude. Four major physiognomic zones, including six associations are recognized within the transect studied: (1) The ‘Pre-Puna’ belt (2700–3150 m), characterized by a sparse cover of xerophytic subshrubs, including two associations: Acantholippia deserticola-Franseria meyeniana, which occurs over the sedimentary sands around Turi, and Franseria meyeniana-Helogyne macrogyne-Helianthocereus atacamensis, restricted to ravines and canyons. (2) The ‘Puna’ belt (3150–3850 m), physiognomically dominated by shrubs and presenting the highest vegetational cover, including the: Fabiana densa-Baccharis boliviensis, and Junellia seriphioides-Baccharis incarum-Lampaya medicinalis, associations. (3) The ‘High-Andean’ belt, localized above the ‘Puna’, including the Fabiana bryoides-Adesmia horrida and Oxalis exigua-Mulinum crassifolium associations. (4) The ‘Subnival’ belt, a high mountain semi-desert with a poorly developed vegetation. Only three species occur at the upper vegetational limit (4380 m). The phytosociological scheme proposed in this paper can be paralleled with that by Ruthsatz (1977) for the eastern flank of the Andes. A marked contrast in species richness and phytosociological complexity between these Andean regions is pointed out. Lower species richness of the Chilean transect is related to the presence of the Atacama desert, which extends from the coast up to 2700 m in the study area.     

Melanoxa, a new genus in the Urocystidales (Ustilaginomycotina)

A smut fungus, Melanotaenium oxalidis, forming dark-coloured spores in the leaves of Oxalis oregana (Oxalidaceae) was collected a few times in the USA. A similar smut fungus on Oxalis acetosella was recently collected in Slovenia. Teliospores, hyphal septations, cellular interactions and ITS and LSU rDNA sequences of these two smuts on Oxalis were examined and the results obtained were compared with each other and with findings in other members of the Ustilaginomycotina. The data show that the specimen from Slovenia is very close to Melanotaenium oxalidis, but represents a new species, and that the two Melanotaenium species occurring on Oxalis are members of the Urocystidaceae. Among the Urocystidaceae, they are morphologically very similar to Flamingomyces, Melanustilospora and Vankya species, but differ from them, and from all other Urocystidaceae, by their multilamellate teliospore walls. In addition, molecular phylogenetic analyses indicated good separation of the Melanotaenium species from Flamingomyces, Melanustilospora and Vankya. Accordingly, a new genus, Melanoxa, and a new species, M. oxalidiellae, are described, and a new combination, Melanoxa oxalidis, is proposed for Melanotaenium oxalidis.     

Paraphyly of Cinclodes fuscus (Aves: Passeriformes: Furnariidae): Implications for taxonomy and biogeography

The Andes are a hotspot of global avian diversity, but studies on the historical diversification of Andean birds remain relatively scarce. Evolutionary studies on avian lineages with Andean–Patagonian distributions have focused on reconstructing species-level phylogenies, whereas no detailed phylogeographic studies on widespread species have been conducted. Here, we describe phylogeographic patterns in the Bar-winged Cinclodes (Cinclodes fuscus), a widespread and common species of ovenbird (Furnariidae) that breeds from Tierra del Fuego to the northern Andes. Traditionally, C. fuscus has been considered a single species composed of nine subspecies, but its long and narrow range suggests the possibility of considerable genetic variation among populations. Sequences of two mitochondrial genes revealed three discrete and geographically coherent groups of C. fuscus, occupying the southern, central, and northern Andes. Surprisingly, phylogenetic analyses indicated that these groups were more closely related to other species of Cinclodes than to each other. Relationships of the southern and northern C. fuscus clades to other species of Cinclodes were straightforward; in combination with available information on plumage, behavioral, and vocal variation, this suggests that each should be recognized as a distinct biological species. The central Andean group was paraphyletic with respect to C. oustaleti, and relationships among these taxa and C. olrogi were poorly resolved. We suggest that the central Andean C. fuscus should also be considered a different species, pending new information to clarify species limits in this group. These new phylogenetic data, along with recently developed methods, allowed us to review the biogeography of the genus, confirming southern South America and the central Andes as important areas for the diversification of these birds.     

Out of Amazonia again and again: episodic crossing of the Andes promotes diversification in a lowland forest flycatcher

Most Neotropical lowland forest taxa occur exclusively on one side of the Andes despite the availability of appropriate habitat on both sides. Almost all molecular phylogenies and phylogenetic analyses of species assemblages (i.e. area cladograms) have supported the hypothesis that Andean uplift during the Late Pliocene created a vicariant barrier affecting lowland lineages in the region. However, a few widespread plant and animal species occurring in lowland forests on both sides of the Andes challenge the generality of this hypothesis. To understand the role of the Andes in the history of such organisms, we reconstructed the phylogeographic history of a widespread Neotropical flycatcher (Mionectes oleagineus) in the context of the other four species in the genus. A molecular phylogeny based on nuclear and mitochondrial sequences unambiguously showed an early basal split between montane and lowland Mionectes. The phylogeographic reconstruction of lowland taxa revealed a complex history, with multiple cases in which geographically proximate populations do not represent sister lineages. Specifically, three populations of M. oleagineus west of the Andes do not comprise a monophyletic clade; instead, each represents an independent lineage with origins east of the Andes. Divergence time estimates suggest that at least two cross-Andean dispersal events post-date Andean uplift.     

Origins of domestication and polyploidy in oca (Oxalis tuberosa; Oxalidaceae). 3. AFLP data of oca and four wild, tuber-bearing taxa

Many crops are polyploids, and it can be challenging to untangle the often complicated history of their origins of domestication and origins of polyploidy. To complement other studies of the origins of polyploidy of the octoploid tuber crop oca (Oxalis tuberosa) that used DNA sequence data and phylogenetic methods, we here compared AFLP data for oca with four wild, tuber-bearing Oxalis taxa found in different regions of the central Andes. Results confirmed the divergence of two use-categories of cultivated oca that indigenous farmers use for different purposes, suggesting the possibility that they might have had separate origins of domestication. Despite previous results with nuclear-encoded, chloroplast-expressed glutamine synthetase suggesting that O. picchensis might be a progenitor of oca, AFLP data of this species, as well as different populations of wild, tuber-bearing Oxalis found in Lima Department, Peru, were relatively divergent from O. tuberosa. Results from all analytical methods suggested that the unnamed wild, tuber-bearing Oxalis found in Bolivia and O. chicligastensis in NW Argentina are the best candidates as the genome donors for polyploid O. tuberosa, but the results were somewhat equivocal about which of these two taxa is the more strongly supported as oca's progenitor.     

Taxonomic revision of the olingos (Bassaricyon), with description of a new species,the Olinguito

We present the first comprehensive taxonomic revision and review the biology of the olingos, the endemic Neotropical procyonid genus Bassaricyon, based on most specimens available in museums, and with data derived from anatomy, morphometrics, mitochondrial and nuclear DNA, field observations, and geographic range modeling. Species of Bassaricyon are primarily forest-living, arboreal, nocturnal, frugivorous, and solitary, and have one young at a time. We demonstrate that four olingo species can be recognized, including a Central American species (Bassaricyon gabbii), lowland species with eastern, cis-Andean (Bassaricyon alleni) and western, trans-Andean (Bassaricyon medius) distributions, and a species endemic to cloud forests in the Andes. The oldest evolutionary divergence in the genus is between this last species, endemic to the Andes of Colombia and Ecuador, and all other species, which occur in lower elevation habitats. Surprisingly, this Andean endemic species, which we call the Olinguito, has never been previously described; it represents a new species in the order Carnivora and is the smallest living member of the family Procyonidae. We report on the biology of this new species based on information from museum specimens, niche modeling, and fieldwork in western Ecuador, and describe four Olinguito subspecies based on morphological distinctions across different regions of the Northern Andes.     

Areas of endemism and distribution patterns for Neotropical Piper species (Piperaceae)

Aim The study aimed to establish areas of endemism and distribution patterns for Neotropical species of the genus Piper in the Neotropical and Andean regions by means of parsimony analysis of endemicity (PAE) and track‐compatibility analysis. Location The study area includes the Neotropical region and the Northern Andean region (Páramo‐Punan subregion). Methods We used distribution information from herbarium specimens and recent monographic revisions for 1152 species of Piper from the Neotropics. First, a PAE was attempted in order to delimit the areas of endemism. Second, we performed a track‐compatibility analysis to establish distribution patterns for Neotropical species of Piper. Terminology for grouping Piper is based on recent phylogenetic analyses. Results The PAE yielded 104 small endemic areas for the genus Piper, 80 of which are in the Caribbean, Amazonian and Paranensis subregions of the Neotropical region, and 24 in the Páramo‐Punan subregion of the Andean region. Track‐compatibility analysis revealed 26 generalized tracks, one in the Páramo‐Punan subregion (Andean region), 19 in the Neotropical region, and six connecting the Andean and Neotropical regions. Both the generalized tracks and endemic areas indicate that distribution of Piper species is restricted to forest areas in the Andes, Amazonia, Chocó, Central America, the Guayana Shield and the Brazilian Atlantic coast. Main conclusions Piper should not be considered an Andean‐centred group as it represents two large species components with distributions centred in the Amazonian and Andean regions. Furthermore, areas of greater species richness and/or endemism are restricted to lowland habitats belonging to the Neotropical region. The distribution patterns of Neotropical species of Piper could be explained by recent events in the Neotropical region, as is the case for the track connecting Chocó and Central America, where most of the species rich groups of the genus are found. Two kinds of event could explain the biogeography of a large part of the Piper taxa with Andean–Amazonian distribution: pre‐Andean and post‐Andean events.     

Diversification of the American bulb-bearing Oxalis (Oxalidaceae): Dispersal to North America and modification of the tristylous breeding system

? Premise of the study: The American bulb-bearing Oxalis (Oxalidaceae) have diverse heterostylous breeding systems and are distributed in mountainous areas from Patagonia to the northeastern United States. To study the evolutionary processes leading to this diversity, we constructed the first molecular phylogeny for the American bulb-bearing Oxalis and used it to infer biogeographic history and breeding system evolution. ? Methods: We used DNA sequence data (nuclear ribosomal internal transcribed spacer, trnL-trnL-trnF, trnT-trnL, and psbJ-petA) to infer phylogenetic history via parsimony, likelihood, and Bayesian analyses. We used Bayes Multistate to infer ancestral geographic distributions at well-supported nodes of the phylogeny. The Shimodaira-Hasegawa (SH) test distinguished among hypotheses of single or multiple transitions from South America to North America, and tristyly to distyly. ? Key results: The American bulb-bearing Oxalis include sampled members of sections Ionoxalis and Pseudobulbosae and are derived from a larger clade that includes members of sections Palmatifoliae, Articulatae, and the African species. The American bulb-bearing Oxalis comprise two clades: one distributed in SE South America and the other in the Andes and North America. An SH test supports multiple dispersals to North America. Most sampled distylous species form a single clade, but at least two other independent distylous lineages are supported by the topologies and SH tests. ? Conclusions: Phylogenetic results suggest the American bulb-bearing Oxalis originated in southern South America, dispersed repeatedly to North America, and had multiple transitions from tristyly to distyly. This study adds to our understanding of biogeographic history and breeding system evolution and provides a foundation for more precise inferences about the study group.     

Bird diversity along elevational gradients in the Andes of Colombia: area and mass effects

Aim The decrease in species richness with increasing elevation is a widely recognized pattern. However, recent work has shown that there is variation in the shape of the curve, such that both negative monotonic or unimodal patterns occur, influenced by a variety of factors at local and regional scales. Discerning the shape of the curve may provide clues to the underlying causes of the observed pattern. At regional scales, the area of the altitudinal belts and mass effects are important determinants of species richness. This paper explores the relationship between bird species richness, elevation, mass effects and area of altitudinal zones for birds in tropical mountains. Location The three Andean ranges of Colombia and the peripheral mountain ranges of La Macarena and Santa Marta. Methods Lists of bird species were compiled for altitudinal belts in eastern and western slopes of the three Andean Cordilleras and for La Macarena and Santa Marta. The area of the altitudinal belts was computed from digital elevation models. The effect of area was analysed by testing for differences among altitudinal belts in the slopes and intercepts of the species‐area relationships. Mass effects were explored by separately analysing two sets of species: broadly distributed species, i.e. lowland species whose distributions extend into the Andes, and tropical Andean species, i.e., species that evolved in the Andes. Results Plotting total number of species in each altitudinal belt revealed a decline in species richness with elevation. In slopes with a complete elevational gradient from lowlands to mountain peaks, the decrease was monotonic. In internal Andean slopes where the lower elevational belts are truncated, there was a peak at mid elevations. There was a linear relationship between number of species and area of the altitudinal belts. When controlling for area, there were no differences in the number of species among altitudinal belts (500–2600 m), except for the two upper‐elevation zones (2600–3200 and > 3200 m), which had lower species richness. Diversity of widely distributed species declined monotonically with elevation, whereas tropical Andean species exhibited a mid‐elevation peak. Main conclusions A large proportion of the variation in species richness with elevation was explained by area of the altitudinal belts. When controlling for area, species richness remained constant up to 2600 m and then decreased. This pattern contrasts with a previously reported hump‐shaped pattern for Andean birds. Diversity patterns of widely distributed species suggested that immigration of lowland species inflates diversity of lower elevational belts through mass effects. This influence was particularly evident in slopes with complete altitudinal gradients (i.e. connected to the lowlands). Tropical Andean species, in contrast, were more diverse in mid‐elevational belts, where speciation rates are expected to be higher. The influence of these species was more prevalent in internal Andean slopes with no connection to the lowlands. The decline of species richness at high elevations may be related to higher extinction rates and lower resource levels.