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Guezou A.,Charles Darwin Foundation | Trueman M.,Charles Darwin Foundation | Trueman M.,University of Western Australia | Buddenhagen C.E.,SWCA Environmental Consultants | And 4 more authors.
PLoS ONE | Year: 2010

Background: Plant invasions are causing habitat degradation in Galapagos. Problems are concentrated on the four inhabited islands. Plants introduced to rural areas in the humid highlands and urban areas on the arid coast act as foci for invasion of the surrounding Galapagos National Park. Methodology/Principal Findings: Here we present results of the most comprehensive inventory to date of alien vascular plants in the inhabited areas of Galapagos. The survey was conducted between 2002 and 2007, in 6031 properties (97% of the total) on Floreana, Isabela, San Cristobal and Santa Cruz Islands. In total 754 alien vascular plant taxa were recorded, representing 468 genera in 123 families. Dicotyledons represented 554 taxa, monocotyledons 183, there were 7 gymnosperms and 10 pteridophytes. Almost half (363) of the taxa were herbaceous. The most represented families were Fabaceae (sensu lato), Asteraceae and Poaceae. The three most recorded species in the humid rural areas were Psidium guajava, Passiflora edulis and Bryophyllum pinnatum, and in the dry urban areas, Aloe vera, Portulaca oleracea and Carica papaya. In total, 264 (35%) taxa were recorded as naturalized. The most common use for taxa was ornamental (52%). Conclusions/Significance: This extensive survey has increased the known alien vascular flora of Galapagos by 257 species, giving a ratio of alien to native taxa of 1.57:1. It provides a crucial baseline for plant invasion management in the archipelago and contributes data for meta analyses of invasion processes worldwide. A repeat of the survey in the future would act as an effective early detection tool to help avoid further invasion of the Galapagos National Park. © 2010 Guézou et al. Source

Ong L.,SWCA Environmental Consultants | Holland K.N.,Hawaii Institute of Marine Biology
Marine Biology | Year: 2010

Parrotfishes can be significant bioeroders and sediment producers on coral reefs. We quantified the bioerosion rates of two similarly sized Hawaiian parrotfishes with two different feeding modes (Scarus rubroviolaceus-a scraper and Chlorurus perspicillatus-an excavator). The results showed that feeding modes did not affect bioerosion rates but that bioerosion rates were size dependent, with largest individuals (S. rubroviolaceus 45-54 cm FL) bioeroding up to 380 ± 67 kg ind-1 year-1. The size for onset of bioerosion capabilities for both species was 15 cm. Grazing by the two species consumed 60% of the carbonate production of the fore reef area, suggesting that large parrotfishes in Hawaii are ecologically important bioeroders. As individual large S. rubroviolaceus contributed disproportionately more to bioerosion and sediment production than the equivalent biomass of smaller conspecifics, management strategies designed to retain normal reef bioerosion rates should seek to preserve the historical size structure of S. rubroviolaceus populations and to especially protect the larger size classes. © 2010 Springer-Verlag. Source

Chimera C.G.,Pacific Cooperative Studies Unit | Buddenhagen C.E.,SWCA Environmental Consultants | Clifford P.M.,Pacific Cooperative Studies Unit | Clifford P.M.,University of Hawaii at Manoa
Biofuels | Year: 2010

Biofuel crops are increasingly promoted as environmental and economical solutions to global energy needs, but actual benefits versus costs may be less favorable than advocates claim. Among the risks associated with their cultivation is the potential to exacerbate the invasive species problem. Evidence is growing that many proposed biofuel crops are ideally suited to become successful invaders. We compared actual and candidate terrestrial biofuel crops suitable for temperate and tropical climates with introduced, nonbiofuel species, and demonstrated that biofuel species are almost three-times more likely to naturalize and over twice as likely to be invasive as nonbiofuel crops in both climatic conditions. Similar potential may exist for algae biofuels. The risks could be mitigated, and unintended environmental costs avoided, by implementing precautions including assessing and removing the worst invaders from consideration, selecting lower risk species for widespread cultivation, and actively controlling the spread of crops from cultivated areas. © 2010 Future Science Ltd. Source

Brunelle A.,University of Utah | Minckley T.A.,University of Wyoming | Lips E.,Great Basin | Burnett P.,SWCA Environmental Consultants
Journal of Quaternary Science | Year: 2013

Records of past vegetation and fire history can be complicated by changes in the depositional environment of a sampling location. However, these changes can alternatively be used as a measure of climate variability. Our study site, ca. 18.0cal. ka BP record from Little Brooklyn Lake, Wyoming, located near the crest of the Snowy Range, records three moisture states. Initially, the lake was likely a glacier-fed pond indicated by the presence of Pediastrum algae colonies. Around 13.0 cal. ka BP this pond transitioned to a meadow environment, suggested by the loss of Pediastrum algae colonies and slow sedimentation rates. Meadow conditions were maintained until ca. 5.0 cal. ka BP when Pediastrum algae colony abundance increased, indicating the formation of a shallow lake. From 18.0 to ca. 5.0 cal. ka BP, the pollen record is suggestive of alpine vegetation conditions with relatively high spruce and herbaceous taxa. Low charcoal influx also characterizes the period between 18.0 and 5.0 cal. ka BP. After 5.0 cal. ka BP, the coincidence of the formation of shallow lake and pollen data, indicating a shift to a spruce and fir forest, suggests an increase in effective moisture. Fire remained rare in this basin over the entire record, however, once the lake established sedimentation rates and charcoal influx increased. © 2013 John Wiley & Sons, Ltd. Source

Plentovich S.,University of Hawaii at Manoa | Eijzenga J.,SWCA Environmental Consultants | Eijzenga H.,Bishop Museum | Smith D.,135 Makiki Heights Drive
Biological Invasions | Year: 2011

Invasive species eradication and control are considered vital components of the conservation, restoration, and management of many native ecosystems. Invasive ants, which are notoriously difficult to eradicate, can cause catastrophic changes in ecosystems and are aggressive colonists. Here we report the eradication and control of two widely distributed invasive ants and subsequent unanticipated effects on arthropod and avian communities. We used a paired experimental design that included 1 year of baseline data collection, to test the effects of the formicide hydramethylnon on abundances of two ant species on two pairs of offshore islets. Pheidole megacephala was eradicated from the treated islet in pair 1 and was not detected during 2003-2008. On pair 2 Solenopsis geminata numbers declined, but the species remained present. Target ant densities remained high on untreated islets. Application of hydramethylnon reduced numbers of alien cockroaches (Order: Blattaria), but we did not detect effects on other non-target arthropods. The eradication of P. megacephala was followed by dynamic compositional changes in the ant community, including the apparent colonization by three species (S. geminata, Tetramorium bicarinatum and Anoplolepis gracilipes) previously undetected on the islet. One of these, A. gracilipes, underwent a rapid range expansion during 2006-2008 which corresponded with reduced seabird nesting success. We conclude that hydramethylnon can be used effectively to eradicate P. megacephala. However, ant eradications can have detrimental effects on ecosystems and the potential for subsequent colonization of sites by other ant species that may be more harmful and more difficult to eradicate needs to be considered. © 2010 Springer Science+Business Media B.V. Source

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