8 results on '"Keppel, Gunnar"'
Search Results
2. Dry forests of the Galápagos: a comparative assessment of a World Heritage Site
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Gonzalo Rivas-Torres, Thomas W. Gillespie, Gunnar Keppel, Chelsea Robinson, Gillespie, Thomas W, Keppel, Gunnar, Robinson, Chelsea M, and Rivas-Torres, Gonzalo
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0106 biological sciences ,Tropical and subtropical dry broadleaf forests ,010504 meteorology & atmospheric sciences ,Ecology ,biology ,Diameter at breast height ,Gentry's transect method ,Scalesia ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Geography ,Liana ,Galápagos archipelago ,Threatened species ,floristic composition ,tropical dry forest ,plant species richness ,IUCN Red List ,Conservation status ,Species richness ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
Despite worldwide knowledge of the importance of the Galápagos archipelago, there is little comparative plot data from the forests in the dry regions. We examined patterns of woody plant (≥2.5 cm diameter at breast height (DBH)) species richness and structure using Gentry's transect method (0.1 ha) on the three largest islands in the Galápagos. We identified the conservation status of woody plants within the dry forest region, assessed forest cover and change in the region, and compared field results to other tropical dry forests in the Pacific. Of the 22 species encountered (11 native, 11 endemic), there were no non-native species and only one threatened species. Isabela, Santa Cruz and San Cristóbal have similar overall levels of species, genera, family and liana richness per site, but significantly different tree species richness, density and tree height per transect. Geospatial databases identified 51 species (native 40%, endemic 60%) of woody plants (≥2.5 cm DBH) within the dry forest region of the Galápagos and 13 species (10 from the genus Scalesia) on the IUCN Red List. There is an estimated 551.97 km2 of dry forest in the Galápagos and there has been little change (
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- 2020
3. Invasive alien palm Pinanga coronata threatens native tree ferns in an oceanic island rainforest
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Sainivalati Vido, Gunnar Keppel, Hans Juergen Boehmer, Michael J. B. Dyer, Marika Tuiwawa, Dyer, Michael JB, Keppel, Gunnar, Tuiwawa, Marika, Vido, Sainivalati, and Boehmer, Hans Juergen
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0106 biological sciences ,Biodiversity ,Distribution (economics) ,Plant Science ,Rainforest ,Biology ,010603 evolutionary biology ,01 natural sciences ,biodiversity loss ,Abundance (ecology) ,Botany ,Ornamental plant ,Fiji ,14. Life underwater ,Ecology, Evolution, Behavior and Systematics ,pantropics ,invasive ornamental palm ,Ecology ,business.industry ,010604 marine biology & hydrobiology ,South Pacific Islands ,15. Life on land ,Native plant ,Cyatheaeceae ,Biological dispersal ,Palm ,business - Abstract
Invasive ornamental plants are a global problem that can have severe impacts on native biodiversity, especially on islands. To determine whether the invasive, ornamental ivory-cane palm Pinanga coronata could be displacing native biodiversity, we investigated its co-distribution with native tree ferns in a Fijian rainforest. We recorded the abundances of P. coronata and tree ferns and related these to environmental variables using linear models and generalised linear mixed-effect models (GLMMs). Distance to an introduction site was the most significant factor predicting the palm's distribution and abundance, suggesting that its current distribution is limited by insufficient time for wider dispersal. P. coronata cover was strongly and negatively related with the abundance of native tree ferns and the palm may therefore be displacing native tree ferns. This relationship was strongest with tree fern seedlings and weakest with mature tree ferns, implying that the palm is preventing the establishment of native tree ferns. This study thus provides strong circumstantial evidence that P. coronata is progressively displacing native tree ferns by preventing seedling establishment and poses a severe threat to Fiji's native biodiversity and ecological processes. Therefore, urgent management is required to control and prevent the further spread of P. coronata and its negative impacts on native plant biodiversity. Management should involve an initial feasibility study to determine the effectiveness of various management strategies, followed by targeted control and/or eradication campaigns and long-term monitoring. Ultimately, well implemented legislation to prevent the spread and introduction of P. coronata and other ornamental plants will be crucial to protect native biodiversity in Fiji and elsewhere Refereed/Peer-reviewed
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- 2019
4. Saving rainforests in the South Pacific: challenges in ex situ conservation
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Gunnar Keppel, Shelley A. James, C. R. McGill, Bronwyn Clarke, Catherine A. Offord, Zoe-Joy Newby, Karen D. Sommerville, Sarah V. Wyse, Sommerville, Karen D., Clarke, Bronwyn, Keppel, Gunnar, McGill, Craig, Newby, Zoe Joy, Wyse, Sarah V., James, Shelley A., and Offord, Catherine A.
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0106 biological sciences ,living collections ,restoration ,Cold storage ,Plant Science ,Rainforest ,Biology ,cryopreservation ,010603 evolutionary biology ,01 natural sciences ,Botany ,Clearing ,tissue culture ,Endemism ,Ecology, Evolution, Behavior and Systematics ,seed banking ,Extinct in the wild ,Agroforestry ,business.industry ,Logging ,orthodox ,15. Life on land ,Ex situ conservation ,seed storage behaviour ,Agriculture ,recalcitrant ,business ,010606 plant biology & botany - Abstract
Rainforests in the South Pacific hold a considerable amount of plant diversity, with rates of species endemism > 80% in some countries. This diversity is rapidly disappearing under pressure from logging, clearing for agriculture or mining, introduced pests and diseases and other anthropogenic sources. Ex situ conservation techniques offer a means to limit the loss of plant diversity. Seed banking is considered the most efficient and cost effective of these techniques but is applicable only to seed capable of tolerating desiccation and cold storage. Data on the degree of tolerance of these conditions was lacking for more than half of the 1503 South Pacific rainforest genera examined for this review. Of the 710 genera for which data were available, the storage behaviour of 324 was based on an assessment of only one or two species, although 76% of those genera contained at least 10 species. Many of the unstudied or poorly studied genera are shared across several South Pacific nations, providing an excellent opportunity for collaboration on future ex situ research and conservation. Of the 386 genera for which three or more species have been studied, 343 have a very high proportion of species ( > 95% of those tested) that are suitable for seed banking. Seed banking could therefore provide a suitable means for preserving a large proportion of the rainforest flora before it becomes extinct in the wild. Alternatives for preserving species that are not suitable for seed banking are also discussed. Refereed/Peer-reviewed
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- 2017
5. Local and expert knowledge improve conservation assessment of rare and iconic Fijian tree species
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Isaac A. Rounds, Nunia T. Thomas, Alifereti Naikatini, Robert L. Pressey, Gunnar Keppel, Keppel, Gunnar, Naikatini, Alifereti, Rounds, Isaac A., Pressey, Robert L., and Thomas, Nunia T.
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Near-threatened species ,Ecology ,Agroforestry ,Endangered species ,extinction risk ,islands ,Regional Red List ,developing nations ,Conservation-dependent species ,Dacrydium nausoriense ,endangered species ,Biology ,biology.organism_classification ,IUCN Red List ,South Pacific ,conservation threat assessment ,expert knowledge ,Threatened species ,Conservation status ,traditional knowledge ,Nature and Landscape Conservation - Abstract
In many developing countries, threatened species lists are unavailable and IUCN Red Lists are very incomplete. Because limited resources are available for conservation in developing countries, detailed field assessments and scientific study of threatened species are often not feasible. However, considerable knowledge about biodiversity exists among experts and local land users. We used questionnaires as part of field surveys to compile information about the abundance, conservation threats, distribution, and ecology of populations of four threatened and iconic target species in Fiji (Acmopyle sahniana, Dacrydium nausoriense, Podocarpus affinis [all Podocarpaceae], and Cynometra falcata [Leguminosae]). These questionnaires were completed in the field for all known populations by an assessor, compiling field observations and measurements with information from local land users and local and outside experts. For the four species in this study, the questionnaires improved estimates of population size, identified previously unknown populations, provided estimates of regeneration, and identified key conservation threats. Species of highly fragmented remnants in drier climates were less protected than those in more contiguous forests of moist climates. The methods employed provided rapid, cost-effective information that can be used to revise IUCN Red List and conservation status assessments and are applicable to other Pacific Island and developing countries. Refereed/Peer-reviewed
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- 2015
6. Species diversity, composition and the regeneration potential of native plants at the Wainiveiota Mahogany Plantation, Viti Levu, Fiji Islands
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Senilolia H. Tuiwawa, Gunnar Keppel, Tuiwawa, Senilolia H, and Keppel, Gunnar
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biology ,Ecology ,Swietenia macrophylla ,Myrtaceae ,Species diversity ,Introduced species ,Endospermum ,Native plant ,native plants ,biology.organism_classification ,Dillenia ,Syzygium ,regeneration ,Botany ,mahogany plantation - Abstract
Mahogany (Swietenia macrophylla King) plantations cover a considerable area on the south-eastern parts of Viti Levu, Fiji. The understorey of these plantations often comprise a diverse, but undocumented, assemblage of native plant species. This study investigates the diversity, composition and regeneration potential of native plant species in the Wainiveiota mahogany plantation 40?50 years after establishment. Ten 10 m x 10 m plots were alternately placed at 10 m intervals perpendicular to a 200 m line transect. A total of 491 individual plants with dbh ≥ 1 cm, comprising 69 species, 51 genera and 34 families, were sampled. In addition to the exotic mahogany, there were 68 native (39 endemic, 24 indigenous and 5 identified to genus only) species recorded. Girronniera celtidifolia Gaud., Dillenia biflora (A.Gray) Martelli ex Dur. & Jacks and Barringtonia edulis Seem. had the highest recruitment and Endospermum macrophyllum (Muell.Arg.) Pax & Hoffm. was the dominant native species. Syzygium Gaertn. (Myrtaceae) was the most diverse genus and Myrtaceae the most diverse family. With 98% of the sapling recruitment consisting of native species, there is potential for re-establishment of a lowland rainforest dominated by native species over time.
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- 2012
7. Climate change impacts on the terrestrial biodiversity and carbon stocks of Oceania
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Wardell-Johnson, GW, Keppel, Gunnar, and Sander, J
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Pacific Island Nations ,refugia ,restoration ,REDD ,endemic species ,deforestation and habitat destruction and degradation ,carbon sequestration ,reforestation ,resilience - Abstract
We review the threats from anthropogenic climate change to the terrestrial biodiversity of Oceania, and quantify decline in carbon stocks. Oceania's rich terrestrial biodiversity is facing unprecedented threats through the interaction of pervasive environmental threats (deforestation and degradation; introduced and invasive species; fragmentation) and the effects of anthropogenic climate change (sea level rise; altered rainfall patterns and increased fire frequency; temperature rises and increased storm severity, extreme weather events and abrupt system changes). All nine of Oceania's terrestrial biomes harbour ecosystems and habitat types that are highly vulnerable under climate change, posing an immense conservation challenge. Current policies and management practices are inadequate and the need for new legislation and economic mechanisms is clear, despite powerful interests committed to limiting progress. Mitigation can be achieved by increasing the effectiveness of the protected area network, by maintaining and effectively managing existing carbon stocks and biodiversity, and by reforestation to sequester atmospheric carbon. A price on carbon emissions may encourage less carbon-intensive energy use while simultaneously encouraging reforestation on long-cleared land, and reducing degradation of native forests. However, realizing these changes will require societal change, and depend on input and collaboration from multiple stakeholders to devise and engage in shared, responsible management. Refereed/Peer-reviewed
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- 2011
8. Diversification history and hybridisation of Dacrydium (Podocarpaceae) in remote Oceania
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Paul D. Hodgskiss, Gunnar Keppel, Andrew J. Lowe, Susana Tuisese, Marika Tuiwawa, Ed Biffin, Peter J. Prentis, Keppel, Gunnar, Prentis, Peter, Biffin, Ed, Hodgskiss, Paul, Tuisese, Susana, Tuiwawa, Marika V, and Lowe, Andrew
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Genetic diversity ,Ecology ,Range (biology) ,Remote Oceania ,introgression ,Introgression ,Plant Science ,endangered species ,Biology ,allozyme ,biology.organism_classification ,phylogeny ,Dacrydium ,Monophyly ,conservation genetics ,Botany ,coniferous tree ,genetic variation ,Biological dispersal ,Podocarpaceae ,divergence ,hybridization ,Oceania Ecozone ,Ecology, Evolution, Behavior and Systematics - Abstract
We examined evolutionary relationships, hybridisation and genetic diversity in species of Dacrydium (Podocarpaceae) in Remote Oceania, where it is restricted to New Caledonia and Fiji. We used cpDNA sequence (trnL–trnF) data to construct a phylogeny and estimate taxon divergence by using a relaxed molecular clock approach. The phylogeny was verified using allozymes, which were also used to investigate genetic diversity of all species and the hybridisation dynamics of two endangered species, D. guillauminii and D. nidulum. Our results suggested that Dacrydium species in Remote Oceania form a monophyletic group that arose and diversified within the last 20 million years through long-distance dispersal and a range of speciation mechanisms. Whereas we detected no hybridisation between the Fijian species D. nausoriense and D. nidulum, we confirmed hybridisation between D. guillauminii and D. araucarioides in New Caledonia and determined introgression to be assymetric from the widespread D. araucarioides into the rare, restricted-range species D. guillauminii. In addition, D. guillauminii had lower genetic diversity than did the other species of Dacrydium studied, which had genetic diversity similar to that of other gymnosperms. Our results provided evidence for the recent and complex diversification of Dacrydium in Remote Oceania. In addition, low genetic diversity of and introgression from D. araucarioides, are of grave concern for the conservation of D. guillauminii. Refereed/Peer-reviewed
- Published
- 2011
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