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Opuntia megasperma var. orientalis Howell

Authors:
Patricia Jaramillo Díaz at Charles Darwin Foundation
Patricia Jaramillo Díaz
Washington Tapia Aguilera at Galapagos Conservancy
Washington Tapia Aguilera
  • Galapagos Conservancy
Alan Tye
Alan Tye
Alan Tye
  • This person is not on ResearchGate, or hasn't claimed this research yet.
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Abstract

El cactus gigante Opuntia megasperma incluye tres variedades, ubicadas en las islas Floreana, San Cristóbal y Española; de estas, O. megasperma var. orientalis se encuentra solo en Española y en los islotes cercanos: Gardner, Osborn, Xarifa (Tortuga) y Oeste. De acuerdo con los criterios de la Unión Internacional para la Conservación de la Naturaleza (UICN), es una especie en peligro de extinción.
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Galápagos
Atlas de
Especies Nativas e Invasoras
Ecuador
UNA CONTRIBUCIÓN AL
MEJOR CONOCIMIENTO
Y CONSERVACIÓN DE
GALÁPAGOS:
Atlas de Galápagos, Ecuador: Especies Nativas e Invasoras
Especies Nativas e Invasoras
Galápagos
Atlas de
Ecuador
Comité editorial:
Pedro Araujo (WWF-Ecuador)
Hugo Arnal (WWF-Ecuador)
Byron Delgado (FCD)
Paola Díaz Freire (FCD)
Arturo Izurieta (FCD)
Gustavo Jiménez-Uzcátegui (FCD)
José R. Marín Jarrín (FCD)
Nicolás Moity (FCD)
Jorge Ramírez (anteriormente de WWF-Ecuador)
Michelle Schuiteman (FCD)
Coordinación gráfica de la publicación:
Rafaela Chiriboga (WWF-Ecuador)
Paola Díaz Freire (FCD)
Daniel Unda García (FCD)
Foto portada: © Tui De Roy
Ilustración digital de portada y contraportada: © Carlyn Iverson
Corrección de estilo, diseño, creación de infografías y diagramación:
Manthra Comunicación • www.manthra.ec • info@manthra.ec
Para citar el documento:
Fundación Charles Darwin (FCD) y WWF-Ecuador. (2018). Atlas de Galápagos, Ecuador: Especies Nativas e
Invasoras. Quito, FCD y WWF-Ecuador.
Para citar un capítulo o una ficha (ejemplo):
Jiménez-Uzcátegui, G. y Parker P. G. (2018). “Viruela aviar, epitelioma contagioso”. Fundación Charles Darwin (FCD)
y WWF-Ecuador. (2018). Atlas de Galápagos, Ecuador: Especies Nativas e Invasoras. Quito, FCD y WWF-Ecuador:
158-159.
ISBN:
978-9978-353-94-3
Imprenta EDIECUATORIAL utiliza papeles y tintas responsables con el medio ambiente.
Nativas
Especies
59
Nativa Clave
Opuntia megasperma var. orientalis
Howell
Plantae : Magnoliophyta : Dicotyledoneae : Caryophyllales : Cactaceae : Opuntia megasperma var. orientalis
© Patricia Jaramillo/FCD
Se encuentra únicamente en la parte centro sur de la isla Española y los islotes Gardner, Osborn, Xarifa (Tortuga) y Oeste; otras variedades
habitan en San Cristóbal y Floreana5, 18-20.
Distribución
Cactus gigante
Situación actual
En la actualidad, la mayoría de los taxones de Opuntia de Ga-
lápagos no se encuentran en peligro de extinción, pero existen
brechas significativas en nuestro conocimiento sobre su distribu-
ción sistemática, ecología y evolución1-4. El cactus gigante Opuntia
megasperma incluye tres variedades, ubicadas en las islas Flo-
reana, San Cristóbal y Española; de estas, O. megasperma var.
orientalis se encuentra solo en Española y en los islotes cerca-
nos: Gardner, Osborn, Xarifa (Tortuga) y Oeste5, 6. De acuerdo con
los criterios de la Unión Internacional para la Conservación de la
Naturaleza (UICN), es una especie en peligro de extinción7, 8. Su
disminución poblacional probablemente fue producida por la in-
troducción de cabras asilvestradas y la disminución drástica de la
población de tortugas gigantes8, 9.
En Galápagos, los Opuntia son árboles y arbustos longevos, cuyas
formas son impresionantemente esculturales. Son considerados
Especies Clave para la dinámica de los ecosistemas de las tierras
bajas, debido a que son fuente de alimento e interactúan con dife-
rentes animales vertebrados e invertebrados que polinizan y disper-
san sus semillas2, 3, 6, 8 .
O. megasperma var. orientalis es uno de los más importantes com-
ponentes estructurales de la vegetación de la isla Española, debido
a que constituye la principal fuente de alimento para la población
de tortugas gigantes, reestablecida mediante el programa de re-
producción en cautiverio y posterior repatriación de tortugas, man-
Importancia ecológica
tenido desde hace 50 años4, 8, 9. Además, al ser uno de los pocos
árboles que existen en la isla, convierten a la especie en una espe-
cie paraguas, pues por sus características físicas y biológicas, así
como sus requerimientos estrictos de hábitat, engloban las necesi-
dades de otras especies, particularmente de fauna8-12. Por lo tanto,
de acuerdo con lo establecido en el Plan de Manejo de las Áreas
Protegidas de Galápagos10, se entiende que, al actuar sobre la con-
servación de estas especies, se actúa también sobre otro número
importante de especies con requerimientos ecológicos similares.
Por ejemplo, sus ramas forman un sitio de anidación importante
para las aves endémicas y sus flores son una de las fuentes más
importantes de néctar y polen para el pinzón de cactus4, 9, 11-17.
Debido a que es una especie endémica amenazada, se requie-
re más información sobre sus relaciones ecológicas y dinámi-
ca poblacional. En particular, se requiere información de los
episodios de El Niño, cuando las raíces se pudren y la planta ab-
sorbe tal volumen de agua que las ramas o la totalidad de la planta
Necesidades de información
se caen. Además, tanto el cactus gigante como las demás especies
de cactus son vulnerables a la posible introducción de Cactoblastis
sp9, 13, 14. Finalmente, es necesario documentar también los cam-
bios que los animales introducidos producen en las poblaciones de
Opuntia sp, los cuales comen y dañan las plántulas.
Cactus gigante
Ficha: Patricia Jaramillo Díaz, Washington Tapia y Alan Tye
Mapa: Byron Delgado
Metodología del mapa: 1
Datos del mapa: Base de datos de colecciones de la Estación
Científica Charles Darwin (ECCD), Proyecto Conservación de
Especies Amenazadas y Galápagos Verde 2050.
Autores
Endémica
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extinction: the mangrove finch on Isabela Island. Philos. Trans. R.
Soc. B Biol. Sci. 365, 1019–1030 (2010).
Galvezia
(Galvezia leucantha) (p. 65)
1. P. Jaramillo, A. Guézou, A. Mauchamp, A. Tye, Fundacion Charles
Darwin Lista de especies de plantas con flores de Galápagos.
Charles Darwin Found. Galapagos Species Checkl. - Lista
Especies Galápagos Fund. Charles Darwin (2016), (disponible
en http://darwinfoundation.org/datazone/checklists/media/
lists/download/2016Sep30_Jaramillo-Diaz_et_al_Galapagos_
Magnoliophyta_Checklist.pdfLast).
2. A. Tye, H. Jäger, Galvezia leucantha subsp porphyrantha
(Scrophulariaceae); a new Shrub Snapdragon endemic to Santiago
Island, Galápagos, Ecuador. Novon. 10, 164–168 (2000).
3. I. Wiggins, D. Porter, Flora of the Galápagos Islands (Stanford
University Press, Stanford, California, U.S.A., 1971).
4. B. Guzmán et al., Evolutionary history of the endangered shrub
snapdragon (Galvezia leucantha) of the Galápagos Islands. Divers.
Distrib., 1–14 (1989).
5. W. Elisens, Genetic divergence in Galvezia (Scrophulariaceae):
Evolutionary and biogeographic relationships among South American
and Galápagos species. Am. J. Bot. 79, 198–206 (1992).
Líquenes
Liquen con clavas espinosas del gladiador
(Acantholichen galapagoensis) (p. 69)
1. M. Dal-Forno et al., From one to six: Unrecognized species
diversity in the genus Acantholichen (lichenized Basidiomycota:
Hygrophoraceae). Mycologia. 108, 38–55 (2015).
2. International Union for the Conservation of Nature, Proposal to
assess Acantholichen galapagoensis Dal-Forno, Bungartz & Lücking.
The Global Fungal Red-List Initiative (2016), (disponible en http://
iucn.ekoo.se/iucn/species_view/1000150/).
3. P. Jørgensen, Acantholichen pannarioides, a new basidiolichen
from South America. The Bryologist. 101, 444–447 (1998).
4. J. Lawrey et al., High concentration of basidiolichens in a
single family of agaricoid mushrooms (Basidiomycota: Agaricales:
Hygrophoraceae). Mycological Research. 113, 114–117 (2009).
5. R. Lücking et al., Do lichens domesticate photobionts like farmers
domesticate crops? Evidence from a previously unrecognized lineage of
filamentous cyanobacteria. American Journal of Botany. 96, 1409–1418 (2009).
Corales
Coral pétreo lobata
(Porites lobata) (p. 73)
1. P. Glynn, G. Wellington, Corals and Coral Reefs of the Galápagos
Islands (University of California Press., Berkeley, 1983).
2. P. Glynn, J. Ault, A biogeographic analysis and review of
the far eastern Pacific coral reef region. Coral Reefs. 19, 1–23
(2000).
3. C. Hickman, Jr., A Field Guide to Corals and Other Radiates of
Galápagos (Sugar Spring Press, Lexington, Virginia, USA, 2008).
4. P. Marti-Puig et al., Extreme phenotypic polymorphism in the coral
genus Pocillopora; micro-morphology corresponds to mitochondrial
groups, while colony morphology does not. Bull. Mar. Sci. 90,
211–231 (2014).
5. Z. Forsman, G. Wellington, G. Fox, R. Toonen, Clues to unraveling
the coral species problem: distinguishing species from geographic
variation in Porites across the Pacific with molecular markers and
microskeletal traits. PeerJ. 3, e751 (2015).
6. D. Paz-Garcia, M. Hellberg, F. García-de-León, E. Balart, Switch
between morphospecies of Pocillopora corals. Am. Nat. 186,
434–440 (2015).
7. G. Edgar et al., Conservation of threatened species in the
Galápagos Marine Reserve through identification and protection of
marine key biodiversity areas. Aquat. Conserv. Mar. Freshw. Ecosyst.
18, 955–968 (2008).
8. C. Hickman, A. Chiriboga, G. Edgar, H. Guzmán, S. Banks,
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(disponible en http://dx.doi.org/10.2305/IUCN.UK.2007.RLTS.
T63580A12683651.en).
9. C. Hickman, G. Edgar, A. Chiriboga, Rhizopsammia wellingtoni.
IUCN Red List Threat. Species (2007), (disponible en http://dx.doi.
org/10.2305/IUCN.UK.2007.RLTS.T63579A12683468.en).
10. P. Glynn et al., Reef coral reproduction in the Eastern Pacific:
Costa Rica, Panama, and Galápagos Islands (Ecuador). Mar. Biol. 109,
355–368 (1991).
11. P. Glynn, State of coral reefs in the Galápagos Islands: natural vs
anthropogenic impacts. Mar. Pollut. Bull. 29, 131–140 (1994).
12. P. Glynn et al., Reef coral reproduction in the eastern Pacific:
Costa Rica, Panamá, and Galápagos Islands (Ecuador). VI.
Agariciidae, Pavona clavus. Mar. Biol. 158, 1601 (2011).
13. P. Glynn et al., Reef coral reproduction in the eastern Pacific: Costa
Rica, Panamá, and Galápagos Islands (Ecuador). VII. Siderastreidae,
Psammocora stellata and Psammocora profundacella. Mar. Biol. 159,
1917–1932 (2012).
14. O. Hoegh-Guldberg et al., Coral reefs under rapid climate change
and ocean acidification. Science. 318, 1737–1742 (2007).
15. P. Glynn, L. D’Croz, Experimental evidence for high temperature
stress as the cause of El Niño-coincident coral mortality. Coral Reefs. 8,
181–191 (1990).
16. D. Manzello, C. Eakin, P. Glynn, in Coral Reefs of the Eastern
Tropical Pacific (Springer, Netherlands, 2017), pp. 517–533.
... orientalis. Sin embargo, el ser humano casi extinguió la tortuga gigante (Chelonoidis hoodensis) y las cabras introducidas causaron una drástica disminución de la población de O. megasperma (Jaramillo et al., 2018d). Tanto el cactus como las tortugas gigantes, son esenciales para el ecosistema y tienen una relación muy importante en la isla (Estupiñan & Mauchamp, 1995;Bibbs et al., 2014). ...
... Los cactus representan una fuente de alimentación importante para la recuperación de la población de tortugas y las tortugas a su vez promueven el establecimiento de los cactus, al ayudar a la dispersión de las semillas. La reducida población de cactus en la isla Española, representa un obstáculo importante para la total recuperación de la especie endémica de tortugas gigantes-especie objeto de un sostenido esfuerzo de conservación durante los últimos 50 años Gibbs et al., 2008;Jaramillo et al., 2018d;Tapia, 2016). ...
El Proyecto Galápagos Verde 2050 (Volumen 1)
Book
Full-text available
  • Apr 2020
Galápagos Verde 2050 (GV2050) es un proyecto multinstitucional e interdisciplinario de la FCD que contribuye activamente a la conservación del capital natural del archipiélago Galápagos y al buen vivir de la población humana local. GV2050 trabaja para recuperar la capacidad de los ecosistemas de generar servicios y promueve prácticas agrícolas sostenibles que permitan a la comunidad vivir en armonía con la naturaleza. GV2050 tiene como objetivo utilizar tecnologías desarrolladas recientemente y diseñadas para superar la barrera de la disponibilidad limitada de agua dulce. Esto incluye varias tecnologías ahorradoras de agua que ya han sido usadas con éxito en todo el mundo para aumentar la tasa de supervivencia y crecimiento de especies de plantas endémicas y nativas, incrementando la disponibilidad del agua en ambientes áridos. El uso de estas tecnologías puede acelerar los procesos de restauración ecológica, aumentar la productividad agrícola y reducir los costos de riego requeridos en las condiciones áridas del archipiélago de Galápagos. GV2050 es un proyecto planificado en tres fases que se encuentra hasta el momento en la fase 2. Hasta ahora ha establecido más de 80 sitios de estudio en siete islas: Baltra, Española, Floreana, Isabela, Plaza Sur, San Cristóbal y Santa Cruz. El proyecto se divide en dos componentes de investigación principales: 1) restauración ecológica de ecosistemas degradados y 2) el desarrollo de agricultura sostenible. Ambos componentes, abordan cuestiones relevantes para la conservación de Galápagos; el primero restaurando poblaciones de plantas nativas y endémicas en ecosistemas degradados y el segundo usando tecnologías ahorradoras de agua para incrementar la producción de cultivos. Todo el trabajo del proyecto es ejecutado por la Estación Científica Charles Darwin (ECCD) brazo operativo de la Fundación Charles Darwin (FCD), con la colaboración de socios estratégicos, especialmente la Dirección del Parque Nacional Galápagos (DPNG), la Agencia de Control y Regulación de la Bioseguridad para Galápagos (ABG) y el Ministerio de Agricultura (MAG).
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... orientalis. However, humans almost completely eliminated the giant tortoise (Chelonoidis hoodensis) and the introduced goats caused a decline in the population of O. megasperma (Jaramillo et al., 2018d). Both the cactus and tortoise are keystone species for the ecosystem and have a very important relationship on the island (Estupiñan & Mauchamp, 1995;Gibbs et al., 2014). ...
... The cacti are an important food source for recovering tortoise population and the tortoises promote cactus establishment by aiding with seed dispersal. The reduced population of cacti on Española presents a major obstacle for the full recovery of the endemic tortoise species-the target of a dedicated conservation effort over the last 50 years Gibbs et al., 2008;Jaramillo et al., 2018d;Tapia, 2016). ...
The Galapagos Verde 2050 Project (Volume 1)
Book
Full-text available
  • Apr 2020
Galapagos Verde 2050 (GV2050) is a multi-institutional and interdisciplinary project of the CDF which actively contributes to the conservation of the natural capital of the Galapagos archipelago and the well-being of its human population. GV2050 works to restore ecosystems and promote sustainable agricultural practices that allow the community to live in harmony with nature. GV2050 aims to use recently developed technologies designed to overcome the barrier of limited freshwater availability. These include various water-saving technologies that have already been successfully used around the world to increase the survival and growth of endemic and native plant species by increasing water availability in arid environments. The use of these technologies can accelerate ecological restoration, increase agricultural productivity and reduce the watering costs required in the arid conditions of the Galapagos archipelago. GV2050 is a tri-phase project that currently, in phase 2, has established more than 80 study sites on seven islands: Baltra, Española, Floreana, Isabela, Plaza Sur, San Cristobal and Santa Cruz. The project is divided in two main research components: 1) ecological restoration of degraded ecosystems and 2) the development of sustainable agriculture. Both components of the GV2050 project address relevant issues in the conservation of the Galapagos Islands; the former, restoring native and endemic plants in degraded ecosystems and the latter using water saving technologies to increase crop production. All of the project’s work is executed by the Charles Darwin Research Station (CDRS) of the Charles Darwin Foundation (CDF), with the collaboration of strategic partners; most notably, the Galapagos National Park (GNP), Biosecurity Agency for Galapagos (ABG) and the Ministry of Agriculture in Galapagos (MAG).
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Effectiveness of water-saving technologies during early stages of restoration of endemic Opuntia cacti in the Galápagos Islands, Ecuador
Article
Full-text available
  • Dec 2019
Restoration of keystone species is a primary strategy used to combat biodiversity loss and recover ecological services. This is particularly true for oceanic islands, which despite their small land mass, host a large fraction of the planet’s imperiled species. The endemic Opuntia spp. cacti are one example and a major focus for restoration in the Galápagos archipelago, Ecuador. These cacti are keystone species that support much of the unique vertebrate animal community in arid zones, yet human activities have substantially reduced Opuntia populations. Extreme aridity poses an obstacle for quickly restoring Opuntia populations though water-saving technologies may provide a solution. The aim of this study was to evaluate current restoration efforts and the utility of two water-saving technologies as tools for the early stages of restoring Opuntia populations in the Galápagos archipelago. We planted 1,425 seedlings between 2013 and 2018, of which 66% had survived by the end of 2018. Compared with no-technology controls, seedlings planted with Groasis Waterboxx ® water-saving technology (polypropylene trays with water reservoir and protective refuge for germinants) had a greater rate of survival in their first two-years of growth on one island (Plaza Sur) and greater growth rate on four islands whereas the “Cocoon” water-saving technology (similar technology but made of biodegradable fiber) did not affect growth and actually reduced seedling survival. Survival and growth rate were also influenced by vegetation zone, elevation, and precipitation in ways largely contingent on island. Overall, our findings suggest that water-saving technologies are not always universally applicable but can substantially increase the survival and growth rate of seedlings in certain conditions, providing in some circumstances a useful tool for improving restoration outcomes for rare plants of arid ecosystems.
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Libro Rojo de las Plantas Endémicas del Ecuador
Book
Full-text available
  • Jan 2011
La protección del patrimonio natural del Ecuador representa un reto para todos, especialmente si se considera que la desaparición de las especies endémicas o restringidas exclusivamente al Ecuador implica su extinción global. La información básica acerca de las especies, los ecosistemas y su estado de conservación sigue siendo insuficiente para cuantificar con precisión la magnitud de las amenazas a la conservación de las especies. A nivel mundial, apenas se ha evaluado el estado de conservación de 4% de las especies vegetales (Baillie et al. 2004) un porcentaje bajo si se considera que las predicciones de uso y abuso de las plantas en el futuro inmediato crecerán proporcionalmente con la población humana. Según Schatz (2009) a fines de siglo la población humana llegará a los nueve o diez billones de habitantes y necesitará duplicar la producción de alimentos e incrementar espacios para vivienda y usar más plantas silvestres para alimento, combustible, construcción y medicina. Por eso, resulta urgente disponer de información científica sistematizada para tomar decisiones responsables sobre el manejo y protección de los ambientes naturales. El Libro Rojo de las Plantas Endémicas del Ecuador busca contribuir a este propósito. Según la Unión Internacional para la Conservación de la Naturaleza (UICN) hasta el año 2000 solamente se habían asignado categorías de amenaza a 461 especies de plantas endémicas del Ecuador. En el año 2000 se publicó la primera edición del “Libro Rojo de las Plantas Endémicas del Ecuador” (Valencia et al. 2000), en el cual se analizó el estado de conservación de 4011 especies endémicas del país. En esta segunda edición, en base a información actualizada sobre la distribución y la taxonomía de las especies, se evalúa el estado de conservación de 4500 especies de plantas endémicas y se asigna una categoría de amenaza a cada una de ellas según los mismos parámetros usados en Valencia et al. (2000) (UICN Categorías y criterios utilizados para la Lista Roja versión 3.1 disponible en: http://www.iucnredlist.org/technicaldocuments/ categories-and-criteria/2001-categories-criteria.) La presente edición de este libro es un trabajo de colaboración entre botánicos e instituciones donde se guardan colecciones de plantas ecuatorianas. El Herbario QCA de la Pontificia Universidad Católica del Ecuador, lideró este proyecto en el cual participaron las siguientes instituciones: Herbario de Loja (LOJA), Herbario Nacional del Museo Ecuatoriano de Ciencias Naturales (QCNE), Herbario del Padre Luis Sodiro S.J. (QPLS), así como los herbarios del Missouri Botanical Garden (MO), Aarhus University (AAU), Universidad de Göttingen (GOET) y muchas otras donde residen nuestros más de 80 colaboradores. En la presente edición, al inicio de cada familia, se describen los cambios observados en estos últimos diez años. En los capítulos introductorios también se incluyen perspectivas generales de conservación de los sistemas terrestres del Ecuador y de cada región natural del país.
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Galápagos macroalgae: A review of the state of ecological knowledge
Article
Full-text available
  • Sep 2016
Previous work has highlighted the critical role of macroalgal productivity and dynamics in supporting and structuring marine food webs. Spatio-temporal variability in macroalgae can alter coastal ecosystems, a relationship particularly visible along upwelling-influenced coastlines. As a result of its equatorial location and nutrient rich, upwelling-influenced waters, the Galápagos Archipelago in the East Pacific, hosts a productive and biodiverse marine ecosystem. Reports and collections of macroalgae date back to the Beagle voyage, and since then, more than three hundred species have been reported. However, their ecology and functional role in the ecosystem is not well understood. According to various disparate and in part anecdotal sources of information, abundant and diverse communities exist in the Western regions of the archipelago, the North is essentially barren, and in the central/South abundance and distribution is variable and less well defined. Both oceanographic conditions and herbivore influence have been theorized to cause this pattern. Extensive changes in macroalgal productivity and community composition have occurred during strong ENSO events, and subsequent declines in marine iguana (an endemic and iconic grazer) populations have been linked to these changes. Iguanas are only one species of a diverse and abundant group of marine grazers in the system, highlighting the potentially important role of macroalgal productivity in the marine food web. This review represents a first compilation and discussion of the available literature and presents topics for future research.
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Reviving Galápagos snails: ancient DNA extraction and amplification from shells of probably extinct Galápagos endemic land snails
Article
Full-text available
  • May 2016
Snail shells represent an abundant source of information about the organisms that build them, which is particularly vital and relevant for species that are locally or globally extinct. Access to genetic information from snail shells can be valuable, yet previous protocols for extraction of DNA from empty shells have met with extremely low success rates, particularly from shells weathered from long-term exposure to environmental conditions. Here we present two simple protocols for the extraction and amplification of DNA from empty land snail shells from specimens of Galápagos endemic snails, including presumably extinct species. We processed 35 shells of the genus Naesiotus (Bulimulidae) from the Galápagos islands, some from species that have not been observed alive in the past 50 years. We amplified and sequenced short fragments (≤244 bp) of mitochondrial DNA (mtDNA) from 18 specimens. Our results indicate that the implementation of an ancient DNA extraction protocol and careful primer design to target short DNA fragments can result in successful recovery of mtDNA data from such specimens.
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Largest global shark biomass found in the northern Galápagos Islands of Darwin and Wolf
Article
Full-text available
  • May 2016
Overfishing has dramatically depleted sharks and other large predatory fishes worldwide except for a few remote and/or well-protected areas. The islands of Darwin and Wolf in the far north of the Galapagos Marine Reserve (GMR) are known for their large shark abundance, making them a global scuba diving and conservation hotspot. Here we report quantitative estimates of fish abundance at Darwin and Wolf over two consecutive years using stereo-video surveys, which reveal the largest reef fish biomass ever reported (17.5 t ha−1{\mathrm{ha}}^{-1} on average), consisting largely of sharks. Despite this, the abundance of reef fishes around the GMR, such as groupers, has been severely reduced because of unsustainable fishing practices. Although Darwin and Wolf are within the GMR, they were not fully protected from fishing until March 2016. Given the ecological value and the economic importance of Darwin and Wolf for the dive tourism industry, the current protection should ensure the long-term conservation of this hotspot of unique global value.
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From one to six: Unrecognized species diversity in the genus Acantholichen (lichenized Basidiomycota: Hygrophoraceae)
Article
Full-text available
  • Nov 2015
We present a taxonomic revision of the lichenized basidiomycete genus Acantholichen, species of which produce a characteristic blue-gray, microsquamulose thallus with spiny apical hyphal cells known as acanthohyphidia. Since its discovery, the genus was thought to be monospecific, only including the generic type, A. pannarioides. However a detailed morphological and anatomical study of recently collected specimens from the Galápagos, Costa Rica, Brazil and Colombia, combined with a molecular phylogenetic analysis of the internal transcribed spacer (ITS1-5.8S-ITS2) region and 28S of the nuc rDNA and RPB2 sequences, revealed a much more diverse and widespread species assemblage. Based on the results of these analyses, we describe five new species in the genus: A. albomarginatus, A. campestris, A. galapagoensis, A. sorediatus and A. variabilis. We also provide an identification key to all species, anatomical and morphological descriptions, photographs and a table comparing main characters of each species.
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Switch between Morphospecies of Pocillopora Corals
Article
Full-text available
  • Apr 2015
  • AM NAT
: Pocillopora corals are the q1 main reef builders in the eastern tropical Pacific. The validity of Pocillopora morphospecies remains under debate because of disagreements between morphological and genetic data. To evaluate the temporal stability of morphospecies in situ, we monitored the shapes of individual colonies in three communities in the southern Gulf of California for 44 months. Twenty-three percent of tagged colonies of Pocillopora damicornis changed to Pocillopora inflata morphology during this time. This switch in identity coincided with a shift to a higher frequency of storms and lower water turbidity (i.e., lower chlorophyll a levels). Seven months after the switch, P. inflata colonies were recovering their original P. damicornis morphology. All colonies of both morphospecies shared a common mitochon-drial identity, but most P. damicornis colonies undergoing change were at a site with low-flow conditions. This is the first in situ study to document switching between described morphospecies, and it elucidates the influence of temporal shifts in environmental conditions on morphologically plastic responses.
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Space, Time and Aliens: charting the dynamic structure of Galápagos pollination networks
Article
Full-text available
  • Jun 2015
Oceanic archipelagos are threatened by the introduction of alien species which can severely disrupt the structure, function and stability of native communities. Here we investigated the pollination interactions in the two most disturbed Galápagos Islands, comparing the three main habitats and the two seasons, and assessing the impacts of alien plant invasions on network structure. We found that the pollination network structure was rather consistent between the two islands, but differed across habitats and seasons. Overall, the arid zone had the largest networks and highest species generalization levels whereas either the transition between habitats or the humid habitat showed lower values. Our data suggest that alien plants integrate easily into the communities, but with low impact on overall network structure, except for an increase in network selectiveness. The humid zone showed the highest nestedness and the lowest modularity, which might be explained by the low species diversity and the higher incidence of alien plants in this habitat. Both pollinators and plants were also more generalized in the hot season, when networks showed to be more nested. Alien species (both plants and pollinators) represented a high fraction (c. 56%) of the total number of interactions in the networks. It is thus likely that, in spite of the overall weak effect we found of alien plant invasion on pollination network structure, these introduced species influence the reproductive success of native ones, and by doing so, they affect the functioning of the community. This certainly deserves further investigation. Published by Oxford University Press on behalf of the Annals of Botany Company.
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Evolutionary history of the endangered shrub snapdragon (Galvezia leucantha) of the Galápagos Islands
Article
  • Dec 2017
Aim The endangered Galápagos shrub snapdragon ( Galvezia leucantha , Antirrhineae, Plantaginaceae) is restricted to small populations on four islands. In this study, we appraised results from taxonomy, genetics, phylogenetics, phylogeography and pollination ecology to reconstruct the evolutionary history of the genus Galvezia . Location Peru, continental Ecuador and Galápagos. Methods We sequenced the nuclear ribosomal ITS and two plastid regions, ndhF and ndhF‐rpL32 , to infer the origin of Galvezia and patterns of colonization to and across the Galápagos archipelago, based on Bayesian inference and statistical parsimony analyses. To investigate genetic diversity and differentiation within G. leucantha , we screened the genome of six populations and obtained 194 AFLP fingerprints. Autogamy tests and pollination network analyses were performed to evaluate the colonization potential and to investigate the structure of the pollinators’ assemblage of Galvezia . Results Relationships of seven nucleotide‐substitution haplotypes and 11 nucleotide‐substitution ribotypes of Galvezia revealed monophyly for the Galapagos species. Dating estimates indicated divergence of the insular Galvezia lineage in the Middle‐Upper Pleistocene (0.66–0.09 Ma). In addition, distribution of genotypes (seven haplotypes, eight ribotypes) across the three continental species showed geographical differentiation, while low differentiation and distribution of G. leucantha . AFLP genetic diversity is relatively high ( H T = 0.109), but a low proportion of the total allelic variance is attributed to variation among subspecies/islands ( H b = 0.035, hierarchical AMOVA : 3.77% of total variance). The endemic bee ( Xylocopa darwinii ) accounted for 87.30% of the floral visits to G. leucantha . Main conclusions We inferred a single origin for an insular lineage that colonized the Galápagos Islands from northern Peru in the Pleistocene. Recent colonization of the archipelago, Pleistocene land bridges between islands and active gene flow promoted by X. darwinii may account for the low‐moderate genetic differentiation of G. leucantha subspecies. An unusual pollination shift from ornithophily (hummingbirds on the continent) to entomophily ( Xylocopa in the Galápagos Islands) is supported.
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Threatened species, a re-evaluation of the status of eight endemic plants of the Galapagos
Article
  • Jan 1998
Although still in relatively good condition, the Galapagos Archipelago suffers from increasing human pressures. Apart from direct actions like hunting and logging, endemic plants and animals are threatened by introduced species, and in many cases the present status of the populations is not known. The conservation status of eight plant species considered endangered was studied from literature and field surveys and the main threats were determined. Each of the eight species is endemic to only one island but in some cases is also present on nearby islets. Of these eight species, one is considered extinct, one critically endangered, and the others suffer various levels of threat. As in all island systems of the world, the main threats are introduced organisms, both plants and animals. The extinct species probably disappeared owing to invasion by Lantana camara, one of the most aggressively invasive plants of the islands, and the most endangered species is threatened by goats. The remaining species seem to be regenerating well and we can expect positive results from protection efforts. Today, only one of the eight species benefits from a direct protection action.
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