Remote locations, such as oceanic islands, typically harbour relatively few species, some of which go on to generate endemic radiations. Species colonising these locations tend to be a non-random subset from source communities, which is thought to reflect dispersal limitation. However, non-random colonisation could also result from habitat filtering, whereby only a few continental species can become established. We evaluate the imprints of these processes on the Galápagos flora by analysing a comprehensive regional phylogeny for ~ 39 000 species alongside information on dispersal strategies and climatic suitability. We found that habitat filtering was more important than dispersal limitation in determining species composition. This finding may help explain why adaptive radiation is common on oceanic archipelagoes - because colonising species can be relatively poor dispersers with specific niche requirements. We suggest that the standard assumption that plant communities in remote locations are primarily shaped by dispersal limitation deserves reconsideration.
We review the systematics of frogs of the Hyloscirtus larinopygion group. A new phylogenetic tree inferred frommitochondrial DNA (partial sequences of 12S rRNA, valine-tRNA, and 16S rRNA genes; ~2.3 kb) of eleven species ofthe H. larinopygion group is provided, based on maximum parsimony, maximum likelihood, and Bayesian analyses. Ourphylogeny confirms the close relationship of members of the H. larinopygion group with Andean relatives of the H.armatus group, which also occurs in the Andes. Hyloscirtus tapichalaca is placed as sister species to the rest of the H.larinopygion group, in which two clades (A+B) are evident. Although ingroup relationships are well supported, themonophyly of the H. larinopygion group and placement of H. tapichalaca require additional testing. Genetic divergencesamong species of the H. larinopygion group are shallow compared to those observed in many other anurans, with geneticdistance among sister species (H. princecharlesi and H. ptychodactylus) as low as 1.31%. However, this pattern isconcordant with radiations in other highland Andean lineages of anurans that show marked morphological or behavioraldifferentiation, but low divergence in mitochondrial markers. Divergence-time analyses (using BEAST) indicate that theHyloscirtus clade is a relatively ancient lineage that appeared in the Eocene, at a minimum age of 51.2 million years ago(MYA), while the H. larinopygion group originated in the Middle-Late Eocene at a minimum age of 40.9 MYA. Ourresults might suggest a rapid radiation of Hyloscirtus starting in the Miocene into the Pliocene, from at least 14.2 MYA tothe most recent divergence between sister taxa at ~2.6 MYA. We also describe two sympatric new species of Hyloscirtusfrom northwestern Ecuador: H. criptico sp. nov. and H. princecharlesi sp. nov. We diagnose them by their phylogeneticposition (they are not sister to each other), genetic divergence, and a unique combination of color patterns, and othermorphological features. Additionally, we describe the suctorial tadpoles and the extreme ontogenic color changes in H.larinopygion, H. lindae, H. pantostictus, H. princecharlesi, H. psarolaimus, and H. tigrinus. Furthermore, we describe theosteology of H. criptico, H. lindae, H. pacha, H. pantostictus, H. princecharlesi, H. psarolaimus, H. ptychodactylus, andH. staufferorum. We describe vocalizations of H. lindae, H. pacha, H. pantostictus, H. pasarolaimus, H. staufferorum, andH. tapichalaca. Hyloscirtus tigrinus is recorded for the first time in Ecuador and its range is extended 62.4 km (airlinedistance), from its southernmost locality record in Departamento de Nariño, Colombia. Most species of the H.larinopygion group are currently severely threatened by extinction, after surviving the catastrophic extinctions in the1980s and 1990s that led to the disappearance of many other sympatric anurans that bred in swiftly flowing water and hadlotic water tadpoles in the Andean highlands. Research and conservation actions are urgently needed for these species. Inorder to better call attention to these conservation issues, we name one of the new species in honor of Prince Charles ofWales, who is contributing significantly to the growth of awareness in the battle against tropical deforestation, climate change, and the catastrophic extinction of rainforest amphibians.
Predator-prey interactions play a key role in the evolution of species traits through antagonistic coevolutionary arms races. The evolution of beak morphology in the Darwin's finches in response to competition for seed resources is a classic example of evolution by natural selection. The seeds of Tribulus cistoides are an important food source for the largest ground finch species (Geospiza fortis, G. magnirostris, and G. conirostris) in dry months, and the hard spiny morphology of the fruits is a potent agent of selection that drives contemporary evolutionary change in finch beak morphology. Although the effects of these interactions on finches are well known, how seed predation affects the ecology and evolution of the plants is poorly understood. Here we examine whether seed predation by Darwin's finches affects the ecology and evolution of T. cistoides. We ask whether the intensity of seed predation and the strength of natural selection by finches on fruit defense traits vary among populations, islands, years, or with varying finch community composition (i.e., the presence/absence of the largest beaked species, which feed on T. cistoides most easily). We then further test whether T. cistoides fruit defenses have diverged among islands in response to spatial variation in finch communities. We addressed these questions by examining seed predation by finches in 30 populations of T. cistoides over 3 yr. Our study reveals three key results. First, Darwin's finches strongly influence T. cistoides seed survival, whereby seed predation varies with differences in finch community composition among islands and in response to interannual fluctuations in precipitation. Second, finches impose phenotypic selection on T. cistoides fruit morphology, whereby smaller and harder fruits with longer or more spines exhibited higher seed survival. Variation in finch community composition and precipitation also explains variation in phenotypic selection on fruit defense traits. Third, variation in the number of spines on fruits among islands is consistent with divergent phenotypic selection imposed by variation in finch community composition among islands. These results suggest that Darwin's finches and T. cistoides are experiencing an ongoing coevolutionary arms race, and that the strength of this coevolution varies in space and time.
Ecuador is one of the most biodiverse countries in the world, but faces severe pressures and threats to its natural ecosystems. Numerous species have declined and require to be objectively evaluated and quantified, as a step towards the development of conservation strategies. Herein, we present an updated National Red List Assessment for amphibian species of Ecuador, with one of the most detailed and complete coverages for any Ecuadorian taxonomic group to date. Based on standardized methodologies that integrate taxonomic work, spatial analyses, and ecological niche modeling, we assessed the extinction risk and identified the main threats for all Ecuadorian native amphibians (635 species), using the IUCN Red List Categories and Criteria. Our evaluation reveals that 57% (363 species) are categorized as Threatened, 12% (78 species) as Near Threatened, 4% (26 species) as Data Deficient, and 27% (168 species) as Least Concern. Our assessment almost doubles the number of threatened species in comparison with previous evaluations. In addition to habitat loss, the expansion of the agricultural/cattle raising frontier and other anthropogenic threats (roads, human settlements, and mining/oil activities) amplify the incidence of other pressures as relevant predictors of ecological integrity. Potential synergic effects with climate change and emergent diseases (apparently responsible for the sudden declines), had particular importance amongst the threats sustained by Ecuadorian amphibians. Most threatened species are distributed in montane forests and paramo habitats of the Andes, with nearly 10% of them occurring outside the National System of Protected Areas of the Ecuadorian government. Based on our results, we recommend the following actions: (i) An increase of the National System of Protected Areas to include threatened species. (ii) Supporting the ex/in-situ conservation programs to protect species considered like Critically Endangered and Endangered. (iii) Focalizing research efforts towards the description of new species, as well as species currently categorized as Data Deficient (DD) that may turn out to be threatened. The implementation of the described actions is challenging, but urgent, given the current conservation crisis faced by amphibians.
We review the systematics of the species of Gastrotheca (Anura: Hemiphractidae) in the highlands of the southern Ecuadorian Andes. We analyzed phylogenetic, morphological, ecological, and acoustic data from populations in the region. We provide an updated phylogenetic hypothesis inferred from a database that contains 42 species of Gastrotheca, and sequences from mitochondrial (12S, 16S, and ND1) and nuclear (POMC and RAG-1) genes. We describe four new endemic biphasic species for Ecuador (Gastrotheca cuencana, G. elicioi, G. turnerorum, and G. yacuri). In addition, we redefine G. lojana, recently resurrected from the synonymy of G. monticola, and redescribe G. litonedis. Furthermore, we describe the tadpoles and ontogenetic color changes in six species (G. cuencana, G. elicioi, G. litonedis, G. lojana, G. pseustes, and G. turnerorum). Also, we describe the calls of seven species (G. cuencana, G. elicioi, G. litonedis, G. lojana, G. pseustes, G. testudinea, and G. yacuri). The phylogenetic relationships estimated here are congruent with previous phylogenetic hypotheses for the group, except for the placement of G. galeata, G. plumbea, G. orophylax, G. nicefori, and G. griswoldi. Because most sister species in Gastrotheca are allopatric, the evolutionarly scenarios that likely have intervened in shaping the diversity are the uplift of the Andes and the formation of cross-Andean river valleys, which probably promoted conditions that acted as dispersal barriers that led to speciation. Many species of Gastrotheca (44%) are highly threatened. Most monophasic species have not been seen since the late 1980s, whereas the highland biphasic species have survived the catastrophic events that led to the disappearance of many other sympatric anurans. Research and conservation actions are urgently needed for all surviving species treated herein, five of which are either Critically Endangered or Endangered because of their restricted distributions (10–1600 km2), habitat destruction and fragmentation, climate change, and pathogens. Two of the new species, G. cuencana, and G. elicioi, mostly are known from the cities of Cuenca and Loja, respectively, where urbanization threatens their survival. In order to call attention to conservation issues, we name one new species to refer to the Yacuri National Park, and the other three in honor of the people from Cuenca, the Turner family, and Elicio E. Tapia, whose actions are helping to halt amphibian extinctions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.