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Displaying 1,851 - 1,860 of 7,105 Publications
- Poeciliids, one of the most invasive species worldwide, are found on almost every continent and have been identified as an ‘‘invasive species of concern’’ in the United States, New Zealand, and Australia. Despite their global prevalence, few studies have quantified their impacts on tropical stream ecosystem structure, function, and biodiversity. Utilizing Hawaiian streams as model ecosystems, we documented how ecological structure, function, and native species abundance differed between poeciliid-free and poeciliid-invaded tropical streams. Stream nutrient yields, benthic biofilm biomass,...AuthorsTara Holitzki, Richard A. MacKenzie, Tracy N. Wiegner, Karla J. McDermidKeywordsSourceEcological Applications. 23(6):1367-1383Year2013
- Fish were sampled from tide pools in Hawaii to determine how exotic mangroves Rhizophora mangle and the use of herbicides to chemically eradicate them are impacting tide pool fish assemblages. Ecological parameters were compared among mangrove-invaded, native vegetated, and non-vegetated tide pools before and after mangroves had been chemically eradicated. Native fish densities were higher than exotic fish densities in all treatments, were dominated by flagtails Kuhlia xenura, did not differ among treatments, and 1 yr after herbicidial eradication of mangroves, were greater than or equal...AuthorsRichard A. MacKenzie, Caitlin KryssKeywordsSourceMarine Ecological Progress Series. 472:219-237Year2013
- We built on previous work by performing a more in-depth examination of a completed landscape fuel treatment network. Our specific objectives were: (1) model hazardous fire potential with and without the treatment network, (2) project hazardous fire potential over several decades to assess fuel treatment network longevity, and (3) assess fuel treatment effectiveness and longevity over a range of two critical fire modeling inputs: surface fuel models and canopy base height. Modeling results demonstrate reductions in the hazardous fire potential across much of the treated landscape, relative...AuthorsBrandon M. Collins, Heather A. Kramer, Kurt Menning, Colin Dillingham, David Saah, Peter Stine, Scott L. StephensSourceForest Ecology and ManagementYear2013
- The last two summers have resulted in historic wildfire activity on the US mainland – 8.2 and 9.1 million acres burned in 2011 and 2012, respectively (National Interagency Fire Center 2012). Unfortunately for Smokey Bear, who may be looking for an opportunity to hang up his shovel for a surfboard for a few months, a trip way out west to the Hawaiian Islands would not serve as a vacation. In fact, Smokey would find "paradise" to have a hornet's nest of fire issues. Indeed, there is fire in paradise even during the "winter" or vacation months, thanks largely to a tropical climate that...AuthorsDouglas Cram, Susan Cordell, James B. Friday, Christian P. Giardina, Creighton M. Litton, Eric Moller, Elizabeth PickettSourceFire and drought in paradise – Say it isn’t so, Smokey. Rural Connections. 7:19-22Year2013
- Wood has played a primary role in the evolution of land plants (Spicer and Groover 2010), but our understanding of the genes and mechanisms underlying wood evolution and development has been limited until recently. Importantly, many of the fundamental questions of woody plant evolution and development are now tractable using genomics and high-capacity sequencing technologies. A major challenge is to integrate the knowledge from traditional disciplines of woody plant research (e.g., anatomy, paleobotany, physiology, and developmental biology) with genomics and sequencing-based technologies....AuthorsAndrew T. Groover, Quentin CronkKeywordsSourceInternational Journal of Plant Science 174(7), 959-963Year2013
- Fire suppression and past logging have dramatically altered forest conditions in many areas, but changes to within-stand tree spatial patterns over time are not as well understood. The few studies available suggest that variability in tree spatial patterns is an important structural feature of forests with intact frequent fire regimes that should be incorporated in restoration prescriptions. We used a rare dataset consisting of mapped locations for all trees P10 cm in three 4-ha plots in 1929 before logging and in 2007/2008, 78 and 79 years after logging, to assess changes in three spatial...AuthorsJamie Lydersen, Malcolm P. North, Eric E. Knapp, Brandon M. CollinsKeywordsSourceForest Ecology and ManagementYear2013
- We examined seasonal reproductive patterns of the Del Norte Salamander, Plethodon elongatus, in mixed conifer and hardwood forests of northwestern California and southwestern Oregon. Seasonal size differences in reproductive structures suggested that maximum spermatogenic activity occurred during the late summer, with spermatozoa transfer to the vasa deferentia occurring in the fall through spring. Maximum development of mature follicles occurred during the winter; however, follicular growth occurred year-round and was asynchronous among individuals. Courtship and mating probably occurred...AuthorsClara A. Wheeler, Hart Welsh, Lisa M. OllivierSourceJournal of Herpetology 47(1):131-137Year2013
- REDD+ and Forest Degradation REDD+ implementation requires two key steps: (1) establish a reference emission level or reference level (RL); and (2) monitor performance against the reference level (RL). A monitoring system must be able to monitor the performance of implementing action plans to reduce emissions. Degradation activities are of concern because it is unknown to what degree they are contributing to emissions, with potentially and in some cases likely significant contributions to emissions. For REDD+ the key feature is the need to estimate the net emissions from anthropogenic-cause...AuthorsPatricia N. ManleySourceIn: Mortenson, Leif A.; Halperin, James J.; Manley, Patricia N.; Turner, Rich L., eds. Proceedings of the international workshop on monitoring forest degradation in Southeast Asia. Gen. Tech. Rep. PSW-GTR-246. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 5-9Year2013
- Degradation is emerging as a common outcome of forest activities, and associated greenhouse gas (GHG) emissions have the potential to be significant. Understanding the activities and drivers of degradation is central to the ability to effectively measure, monitor, and mitigate associated emissions. Current inventories of GHG emissions do not effectively account for degradation because emissions are difficult to detect. We conducted an assessment of degradation activities and monitoring options at the subnational scale within three countries in Southeast Asia: Viet Nam, Cambodia and Lao...AuthorsPatricia N. Manley, Leif Mortenson, James Halperin, Rick TurnerSourceIn: Mortenson, Leif A.; Halperin, James J.; Manley, Patricia N.; Turner, Rich L., eds. Proceedings of the international workshop on monitoring forest degradation in Southeast Asia. Gen. Tech. Rep. PSW-GTR-246. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 11-12Year2013
- Nitrogen deposition, along with habitat losses and climate change, has been identified as a primary threat to biodiversity worldwide (Butchart et al., 2010; MEA, 2005; Sala et al., 2000). The source of this stressor to natural systems is generally twofold: burning of fossil fuels and the use of fertilizers in modern intensive agriculture. Each of these human enterprises leads to the release of large amounts of biologically reactive nitrogen (henceforth contracted to "nitrogen") to the atmosphere, which is later deposited to ecosystems. Because nitrogen is a critical element to all living...AuthorsChristopher M. Clark, Yongfei Bai, William D. Bowman, Jane M. Cowles, Mark E. Fenn, Frank S. Gilliam, Gareth K. Phoenix, Ilyas Siddique, Carly J. Stevens, Harald U. Sverdrup, Heather L. ThroopSourceIn: Levin S.A. (ed.) Encyclopedia of Biodiversity, second edition, Volume 5, Waltham, MA: Academic Press. pp. 519-536Year2013