Seed dispersal by Galápagos tortoises

Aim Large‐bodied vertebrates often have a dramatic role in ecosystem function through herbivory, trampling, seed dispersal and nutrient cycling. The iconic Galápagos tortoises (Chelonoidis nigra) are the largest extant terrestrial ectotherms, yet their ecology is poorly known. Large body size should confer a generalist diet, benign digestive processes and long‐distance ranging ability, rendering giant tortoises adept seed dispersers. We sought to determine the extent of seed dispersal by Galápagos tortoises and their impact on seed germination for selected species, and to assess potential impacts of tortoise dispersal on the vegetation dynamics of the Galápagos. Location Galápagos, Ecuador. Methods To determine the number of seeds dispersed we identified and counted intact seeds from 120 fresh dung piles in both agricultural and national park land. To estimate the distance over which tortoises move seeds we used estimated digesta retention times from captive tortoises as a proxy for retention times of wild tortoises and tortoise movement data obtained from GPS telemetry. We conducted germination trials for five plant species to determine whether tortoise processing influenced germination success. Results In our dung sample, we found intact seeds from > 45 plant species, of which 11 were from introduced species. Tortoises defecated, on average, 464 (SE 95) seeds and 2.8 (SE 0.2) species per dung pile. Seed numbers were dominated by introduced species, particularly in agricultural land. Tortoises frequently moved seeds over long distances; during mean digesta retention times (12 days) tortoises moved an average of 394 m (SE 34) and a maximum of 4355 m over the longest recorded retention time (28 days). We did not find evidence that tortoise ingestion or the presence of dung influenced seed germination success. Main conclusions Galápagos tortoises are prodigious seed dispersers, regularly moving large quantities of seeds over long distances. This may confer important advantages to tortoise‐dispersed species, including transport of seeds away from the parent plants into sites favourable for germination. More extensive research is needed to quantify germination success, recruitment to adulthood and demography of plants under natural conditions, with and without tortoise dispersal, to determine the seed dispersal effectiveness of Galápagos tortoises.     

Bergmann's rule encompasses mechanism: a reply to Olalla‐Tárraga (2011)

The many definitions of Bergmann's rule have resulted in confusion and debate over how and in what organisms to test the original rule. Watt et al. published a paper in 2010, based directly on Bergmann's original paper, in the hopes of clarifying the rule and presenting direct translations to resolve uncertainties. Recently, Olalla‐Tárraga has criticized our publication, stating that we assumed the rule was a causal law, which has narrowed our epistemological scope of the rule. We argue we did not assume the rule was a law and suggest that Olalla‐Tárraga has only focused on the observed pattern and has ignored the proposed mechanism, which is inherent in the definition. We also discuss the proposed mechanism and describe why it cannot apply to ectotherms. Despite this, we encourage a thorough investigation of the mechanisms responsible for maintaining Bergmann's pattern in ectotherms and support Olalla‐Tárraga's quest for a unifying mechanism to explain body size gradients in endotherms and ectotherms.     

Ungrateful predators: capture and the creation of Cofán violence

In this article, I explore the history, logic, and practice of capture among the Cofán people of Amazonian Ecuador. Rather than acting as the subjects of capture, Cofán people have primarily been its objects. Centuries of pre‐Conquest, colonial, and postcolonial violence have exposed Cofán communities to repeated seizures by indigenous and non‐indigenous aggressors. Although capture by enemy others is a feared prospect that typically brings disaster, it also serves as the Cofán nation's central means of acquiring violent powers, which are essential to its defence. By investigating the uncertainties of capture as a productive process, I question dominant representations of native Amazonians as wilful participants in a cosmos of generalized predation, and I issue a plea for openness when considering the diversity of the region's peoples.     

Conservation status of landbirds on Floreana: the smallest inhabited Galápagos Island

On Floreana, the smallest inhabited island in the Galápagos, populations of several species of birds have either been extirpated or, based on anecdotal evidence and small‐scale surveys, are declining. Our objective, therefore, was to conduct a comprehensive survey of landbirds encompassing the entire island during three breeding seasons (2014–2016). We conducted surveys at 59 points in 2014, 257 in 2015, and 295 in 2016. Each survey point was sampled once. We detected 12 species during our surveys. Galápagos Flycatchers, Yellow Warblers, Small and Medium ground‐finches, and Small Tree‐Finches were widely distributed over the entire island. Common Cactus‐Finches and Medium Tree‐Finches had more restricted distributions in the lower or higher parts of the island. Few Dark‐billed Cuckoos (Coccyzus melacoryphus), Paint‐billed Crakes (Neocrex erythrops), Galápagos Doves (Zenaida galapagoensis), and Galápagos Short‐eared Owls (Asio flammeus galapagoensis) were recorded. Small Ground‐Finches and Small Tree‐Finches were found at densities comparable to those on other Galápagos Islands, whereas densities of Galápagos Flycatchers and Yellow Warblers were higher on Floreana than on other islands. Endemic Medium Tree‐Finches were confined to an area of 24 km², mainly in the highlands, but were still widespread and common in their restricted habitat, with the number of territories estimated to be between 3900 and 4700. Of 22 originally occurring landbirds on Floreana, no fewer than 10 species have either been extirpated or are likely to have been extirpated since the arrival of the first human inhabitants. The combined effects of introduced mammals, large‐scale habitat destruction, and direct human persecution were responsible for the extirpation of six species during the 19th century. Three additional species have been extirpated since 1960, likely due to the introduction of the parasitic fly Philornis downsi, and this fly remains a major threat for the remaining bird species. Developing strategies for reducing the impact of these flies on the birds of the Galapagos Islands must be a high priority. In addition, habitat management and restoration, including the control of invasive plants and promotion of native tree species, will be critically important in conserving landbird populations on Floreana.     

Patterns of population differentiation in annual killifishes from the Paraná–Uruguay–La Plata Basin: the role of vicariance and dispersal

Aim To elucidate the role of vicariance versus dispersal at the microevolutionary scale in annual killifish populations belonging to the Austrolebias bellottii species complex (Rivulidae). Within this complex, A. bellottii and A. apaii have low vagility and occur widely within the study area, making them excellent models for testing biogeographic hypotheses of differentiation. Location South America, in the Paraná–Uruguay–La Plata river basin. Methods Molecular data and morphometric analyses were used to reconstruct the phylogeographic history and morphological variation of 24 populations of two taxa of the A. bellottii species complex. Phylogenetic analyses using maximum likelihood (ML) and Bayesian inference (BI) model‐based methods, estimates of clade divergence times implemented in beast , non‐metric multidimensional scaling, analysis of molecular variance results, and morphological analyses elucidated the role of vicariance versus dispersal hypotheses in population differentiation in the aforementioned river basin. Results In the A. bellottii species complex from the Paraná–Uruguay–La Plata river basin, past allopatric fragmentation from vicariance events seems to be the most plausible scenario for diversification since the Late Miocene and more recently since the Plio‐Pleistocene. The Plio‐Pleistocene vicariance produced the differentiation of three major clades in A. bellottii populations. One clade from the eastern Uruguay River drainage was separated from another in western Uruguay and the Paraná–La Plata River drainages. A later vicariance event split populations to the south (lower Paraná–La Plata Basin) and north (middle Paraná) of the western Paraná River drainage. However, our results do not exclude the possibility of dispersal events among A. bellottii populations from both the Uruguay and Paraná river drainages, which could occur in these river basins during hypothesized connectivity cycles of the Late Pliocene and Pleistocene. Main conclusions Past allopatric fragmentation caused by different vicariance events seems to be the main driver of diversification in the A. bellottii species complex since the Plio‐Pleistocene. However, the current molecular data suggest that populations from both drainages of the Paraná–Uruguay rivers may have experienced cycles of connectivity during the Pleistocene, perhaps including multiple vicariance or dispersal events from populations located in the western lower Uruguay River drainage, which encompassed climatic and geological changes in the Paraná–Uruguay–La Plata Basin.     

Long‐term limnological changes in the Ecuadorian páramo: Comparing the ecological responses to climate warming of shallow waterbodies versus deep lakes

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FAM225A promotes sorafenib resistance in hepatocarcinoma cells through modulating miR-130a-5p–CCNG1 interaction network

Chemotherapy resistance is still a key hurdle in current hepatocellular carcinoma (HCC) treatment. Therefore, clarifying the molecular mechanisms contributing to this acquired resistance is urgent for the effective treatment of liver cancer. In this research, we observed that lncRNA FAM225A expression is dramatically up-regulated not only in HCC tissues and cell lines but also in sorafenib-resistant HepG2/SOR cells. Moreover, FAM225A knockdown significantly weakened HepG2/SOR cells resistance to sorafenib treatment by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Similar results were obtained from the tumor xenograft model in mice. Further mechanistic researches revealed that the direct interaction between FAM225A and miR-130a-5p, while miR-130a-5p negatively modulated Cyclin G1 (CCNG1) expression by targeting 3′UTR of CCNG1. MiR-130a-5p inhibition or CCNG1 overexpression could partially offset FAM225A knockdown-induced increased viability of HepG2/SOR cells in response to sorafenib challenge. Collectively, our findings provide evidence that FAM225A/miR-130a-5p/CCNG1 interaction network regulates the resistance of HCC cells to sorafenib treatment and could supply a possible strategy for restoring sorafenib sensitivity in HCC therapy.     

The Temporal Asynchrony of Planktonic Cladocerans Population at Different Environments of the Upper Paraná River Floodplain

The aim of this study was to investigate the existence of synchronic fluctuation patterns in cladoceran populations of the Upper Paraná River floodplain. The following hypothesis were tested: (i) the populations of a given species present the same fluctuation pattern in abundance for different environments and (ii) synchrony is higher when we consider subsets of neighboring environments or those belonging to the same category (e.g., lagoons, rivers). Samplings were performed every three months from February 2000 to November 2002 at 11 sites. To evaluate spatial synchrony, the intraclass correlation coefficient was used. The results showed no significant correlation for the most abundant species, meaning that fluctuation patterns of planktonic cladocerans were asynchronous. Asynchrony indicated that the influence of floods and regional climatic factors was not strong enough to synchronize the populations, suggesting that local factors were more important than regional effects in determining zooplankton abundance patterns. The implications of these results are that the observations from a single environment cannot be extrapolated to other environments in a manner that would allow its use as a sentinel site. This means that a monitoring program for floodplain systems, or at least for the Paraná River floodplain, has to comprise greater spatial extents. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ethnobotany of the Rama of Southeastern Nicaragua and Comparisons with Miskitu Plant Lore<Superscript>1</Superscript>

Ethnobotany of the Rama of Southeastern Nicaragua and Comparisons with Miskitu Plant Lore. The Rama are one of the three Amerindian groups of eastern Nicaragua. This is the first systematic study of Rama ethnobotany. A total of 249 plant species, in 190 genera and 78 families, were documented as useful. Included are 190 species used as medicinals, 80 as food plants, and 99 for other uses. The ethnobotanical lore of two distinct indigenous groups, the Rama and Miskitu, were compared. Out of 249 species used by the Rama, 171, or 69%, were used by both groups, and 78 unique species were used by the Rama. These results have important implications for the understanding of ethnobotany as they demonstrate how unrelated indigenous groups sharing the same ecosystem, though separated by some physical distance, can have significantly similar ethnobotanical lore.

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Resumen   Etnobotánica de los Ramas del Oriente Nicaragüense y Comparasiones con el Saber Etnobotánico de los Miskitus. Los Ramas constituyen uno de los tres grupos Amerindios del oriente Nicaragüense. Este es el primer studio sistemático de la etnobotánica Rama. Se documentó un total de 249 especies de plantas útiles en 190 géneros y 78 familias. Incluyendo 190 especies medicinales, 80 especies alimenticias y 99 especies para usos auxiliares. La erudición etnobotánica de los Ramas y los Miskitus fueron comparados. Un total de 171 de 249 especies documentadas son usados por ambos grupos y 78 especies solo por los Ramas. Estos resultados tienen implicaciones importantes para el entendimiento de la etnobotánica porque demuestran que grupos sin parentesco alguno que comparten el mismo ecosistema aunque separados por cierta distancia pueden tener una similitud significativa en la erudición etnobotánica.

     

Multidate,multisensor remote sensing reveals high density of carbon‐rich mountain peatlands in the páramo of Ecuador

Tropical peatlands store a significant portion of the global soil carbon (C) pool. However, tropical mountain peatlands contain extensive peat soils that have yet to be mapped or included in global C estimates. This lack of data hinders our ability to inform policy and apply sustainable management practices to these peatlands that are experiencing unprecedented high rates of land use and land cover change. Rapid large‐scale mapping activities are urgently needed to quantify tropical wetland extent and rate of degradation. We tested a combination of multidate, multisensor radar and optical imagery (Landsat TM/PALSAR/RADARSAT‐1/TPI image stack) for detecting peatlands in a 2715 km² area in the high elevation mountains of the Ecuadorian páramo. The map was combined with an extensive soil coring data set to produce the first estimate of regional peatland soil C storage in the páramo. Our map displayed a high coverage of peatlands (614 km²) containing an estimated 128.2 ± 9.1 Tg of peatland belowground soil C within the mapping area. Scaling‐up to the country level, páramo peatlands likely represent less than 1% of the total land area of Ecuador but could contain as much as ~23% of the above‐ and belowground vegetation C stocks in Ecuadorian forests. These mapping approaches provide an essential methodological improvement applicable to mountain peatlands across the globe, facilitating mapping efforts in support of effective policy and sustainable management, including national and global C accounting and C management efforts.     

Community trees: Identifying codiversification in the Páramo dipteran community

Groups of codistributed species that responded in a concerted manner to environmental events are expected to share patterns of evolutionary diversification. However, the identification of such groups has largely been based on qualitative, post hoc analyses. We develop here two methods (posterior predictive simulation [PPS], Kuhner–Felsenstein [K–F] analysis of variance [ANOVA]) for the analysis of codistributed species that, given a group of species with a shared pattern of diversification, allow empiricists to identify those taxa that do not codiversify (i.e., “outlier” species). The identification of outlier species makes it possible to jointly estimate the evolutionary history of co‐diversifying taxa. To evaluate the approaches presented here, we collected data from Páramo dipterans, identified outlier species, and estimated a “community tree” from species that are identified as having codiversified. Our results demonstrate that dipteran communities from different Páramo habitats in the same mountain range are more closely related than communities in other ranges. We also conduct simulation testing to evaluate this approach. Results suggest that our approach provides a useful addition to comparative phylogeographic methods, while identifying aspects of the analysis that require careful interpretation. In particular, both the PPS and K–F ANOVA perform acceptably when there are one or two outlier species, but less so as the number of outliers increases. This is likely a function of the corresponding degradation of the signal of community divergence; without a strong signal from a codiversifying community, there is no dominant pattern from which to detect an outlier species. For this reason, both the magnitude of K–F distance distribution and outside knowledge about the phylogeographic history of each putative member of the community should be considered when interpreting the results.     

Type specimens in the Vidal Herbarium at the Real Jardín Botánico,Madrid

Ninety eight type specimens collected by Sebastián Vidal in the Philippines, and kept at the Real Jardín Botánico Herbarium, Madrid (MA), are compiled. Most of these specimens are types of Vidal's names. Only a few are names of other authors (Hoogland, Merrill, and Rolfe). A list of specimens, as well as the indicatio locotypica and number in MA, is presented. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 292–299.     

Colonization of the Galápagos Islands by plants with no specific syndromes for long‐distance dispersal: a new perspective

Since nobody has witnessed the arrival of early plant colonists on isolated islands, the actual long‐distance dispersal (hereafter LDD) has historically been a matter of speculation. In the present study, we offer a new approach that evaluates whether particular syndromes for LDD (i.e. the set of traits related to diaspore dispersal by animals, wind and sea currents) have been favourable in the natural colonization of the Galápagos Islands by plants. Dispersal syndromes of the 251 native genera (509 angiosperm species) presently acknowledged as native were carefully studied, combining data from floristic lists of the Galápagos Islands, diaspore traits, characteristics of continental relatives and our own observations. We used these genera (and occasionally infrageneric groups) as the working units to infer the number of introductions and colonists. A final number of native plants was inferred and analysed after correcting by pollen records of six species from six genera previously considered exotic (palaeobotanical correction). The number of early colonists was also corrected by incorporating information from the few (n= 12) phylogenetic studies of genera from both the Galápagos Islands and the Americas (phylogenetic correction). A total of 372 colonization events were inferred for the native flora using the latest check‐list. The proportions of native colonists grouped into five categories were: endozoochory 16.4%, epizoochory 15.7%, hydrochory 18.6%, anemochory 13.3%, and unassisted diaspores 36.0%. These figures did not vary significantly on analysing only the 99 genera that include endemic species in order to rule out any human‐mediated introductions. Irrespective of the roles of the different agents involved in LDD, diaspores with no special syndrome for LDD (unassisted diapores), such as many dry fruits, have been successful in reaching and colonizing the Galápagos archipelago. This finding leads us to suggest that unpredictable and so far unknown LDD mechanisms should be further considered in the theory of island biogeography.     

Distribution of non‐native suckermouth armoured catfish Pterygoplichthys ambrosettii in the upper Paraná River basin,Brazil

This study describes the invasion of the upper Paraná River basin by Pterygoplichthys ambrosettii based on a literature review and field samples. Pterygoplichthys ambrosettii has been reported in 42 localities throughout the upper Paraná River basin, including the Tietê, Paranapanema, Paraná, Grande and Aguapeí rivers. The ascent of P. ambrosettii after the inundation of the Sete Quedas Falls on the Paraná River and the release of individuals by aquarium hobbyists were the primary drivers of this invasion.     

The reproductive biology of Plagioscion squamosissimus (Heckel, 1840) in the Pará River estuary (Amazon Estuary)

This study describes the reproductive biology of the South American silver croaker Plagioscion squamosissimus (Heckel, 1840) in the Pará River estuary. Data were collected bimonthly from June 2007 to May 2008. In all, 334 specimens were examined. The gonads were processed with histological techniques, and the ovaries were subjected to morphometric analysis. The length at first maturity (L₅₀) values were 16.14 and 21.43 cm total length for females and males, respectively. The sex ratio based on the total number of individuals favoured the females (1.11 females: one male). Macroscopically, the gonads were classified as immature (A), maturing (B), mature (C) and spent (D). Microscopically, four germ cell types were distinguished based on the development of the ovaries. Chromatin nucleolus (I), perinucleolar (II), cortical alveoli (III) and full‐vitellogenic (IV) oocytes were observed in all ovarian stages, except that of the mature individuals which showed the largest number of full‐vitellogenic oocytes (IV), with a mean diameter of 565.4 μm (±147.4). Substantial percentages of individual P. squamosissimus were found to be in a reproductive condition. Reproductive activity was recorded throughout the year in the Pará River estuary, primarily in February/March and August/September.     

Cryptic diversity in Black rats Rattus rattus of the Galápagos Islands,Ecuador

Human activity has facilitated the introduction of a number of alien mammal species to the Galápagos Archipelago. Understanding the phylogeographic history and population genetics of invasive species on the Archipelago is an important step in predicting future spread and designing effective management strategies. In this study, we describe the invasion pathway of Rattus rattus across the Galápagos using microsatellite data, coupled with historical knowledge. Microsatellite genotypes were generated for 581 R. rattus sampled from 15 islands in the archipelago. The genetic data suggest that there are at least three genetic lineages of R. rattus present on the Galápagos Islands. The spatial distributions of these lineages correspond to the main centers of human settlement in the archipelago. There was limited admixture among these three lineages, and these finding coupled with low rates of gene flow among island populations suggests that interisland movement of R. rattus is rare. The low migration among islands recorded for the species will have a positive impact on future eradication efforts.     

Reproductive biology of Ferocactus recurvus (Mill.) Borg subsp. recurvus (Cactaceae) in the Tehuacán‐Cuicatlán Valley,Mexico

• Mexico has one of the highest diversities of barrel cacti species worldwide; however, all are threatened and require conservation policies. Information on their reproductive biology is crucial, but few studies are available. Ferocactus recurvus subsp. recurvus is a barrel cactus endemic to the Tehuacán‐Cuicatlán Valley. Our research aimed to characterise its floral and pollination biology. We hypothesised bee pollination, as suggested by its floral morphology and behaviour, and self‐incompatibility, like most barrel cacti studied.
• Three study sites were selected in the semiarid Zapotitlán Valley, Mexico. We examined 190 flowers from 180 plants to determine: morphometry and behaviour of flowers, flower visitors and probable pollinators, and breeding system.
• Flowers showed diurnal anthesis, lasting 2–5 days, the stigma being receptive on day 2 or 3 after the start of anthesis. Flowers produced scarce/no nectar and main visitors were bees (Apidae), followed by flies (Muscidae), ants (Formicidae), thrips (Thripidae) and hummingbirds (Throchilidae); however, only native bees and occasionally wasps contacted the stigma and anthers. Pollination experiments revealed that this species is self‐incompatible and xenogamous. In natural conditions, fruit set was 60% and cross‐pollination fruit set was 100%. Percentage seed germination resulting from cross‐pollination was higher than in the control treatment.
• Our results provide ecological information for conservation programmes to ensure a high probability of breeding and seed production in natural populations of F. recurvus.

     

The vector ecology of introduced Culex quinquefasciatus populations,and implications for future risk of West Nile virus emergence in the Galápagos archipelago

Culex quinquefasciatus Say (Diptera: Culicidae), an important vector of West Nile virus (WNV) in the U.S.A., was first detected on the Galápagos Islands (Ecuador) in the 1980s. However, little is known of its ecology, distribution or capacity for arbovirus transmission in the Galápagos. We characterize details of lifecycle (including gonotrophic period), temporal abundance, spatial distribution, vector competence and host‐feeding behaviour. Culex quinquefasciatus was detected on five islands of the Galápagos during 2006–2011. A period of 7–14 days was required for egg–adult emergence; water salinity above 5 ppt was demonstrated to hinder larval development. Blood‐meal analysis indicated feeding on reptiles, birds and mammals. Assessment of WNV vector competency of Galápagos C. quinquefasciatus showed a median infectious dose of 7.41 log₁₀ plaque‐forming units per millilitre and evidence of vertical transmission (minimal filial infection rate of 3.7 per 1000 progeny). The distribution of C. quinquefasciatus across the archipelago could be limited by salt intolerance, and its abundance constrained by high temperatures. Feeding behaviour indicates potential to act as a bridge vector for transmission of pathogens across multiple taxa. Vertical transmission is a potential persistence mechanism for WNV on Galápagos. Together, our results can be used for epidemiological assessments of WNV and target vector control, should this pathogen reach the Galápagos Islands.     

First record of non‐native hybrid catfish Pseudoplatystoma reticulatum × Leiarius marmoratus in the Upper Paraná River basin,Brazil

The aim of this study is to report the presence of a three non‐native hybrid long‐whiskered catfishes (family Pimelodidae) in the Upper Paraná River basin, Brazil. Genetic analyses demonstrated that the three presumptive hybrids were a result of the crossbreeding of Pseudoplatystoma reticulatum (central Amazonas River basin and Lower Paraná River) and Leiarius marmoratus (Amazonas, Essequibo and Orinoco rivers), producing a hybrid commonly known in Brazil as cachandiá. The potential threat to biodiversity, due to possible genetic contamination, competition and predation of wild stocks, of such artificially produced hybrid fishes is discussed.