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Herbicidal control of bridal creeper (Asparagus asparagoides) in an ecologically sensitive environment

Jusaitis, Manfred

Asparagus asparagoides (bridal creeper) is a highly invasive noxious environmental weed in southern Australia. It poses a severe threat to biodiversity and conservation in temperate natural ecosystems. Pterostylis arenicola, a threatened terrestrial orchid endemic to South Australia, is directly imperilled by this weed in most of its remnant populations. The coincident growth phenologies of orchid and weed make for an ecologically sensitive environment when considering methods of weed control or eradication. To minimise impact on the orchid and its ecosystem, this paper examines the efficacy of herbicide application for A. asparagoides control using the weed wiping technique, comparing it to the conventional spray application method. The most prolonged control of A. asparagoides was achieved after a single wipe-application of 1.5 g a.i. (active ingredient) L 1 metsulfuron methyl, either alone or in combination with 120 g a.i.L 1 glyphosate, both treatments giving significantly better weed control five years after treatment than comparable spray applications. An investigation of the effect of glyphosate on cultures of the mycorrhizal fungus isolated from P. arenicola indicated a significant decline in mycelial growth with increasing herbicide concentration over the range 0.53.0 kg a.i. ha 1. These results provide further incentive for the use of ecologically sensitive herbicide application techniques, such as weed wiping, in areas of high conservation concern.

Update on the environmental and economic costs associated with alien-invasive species in the United States

Morrison, Doug

Pimentel, David

Zuniga, Rodolfo

Invading alien species in the United States cause major environmental damages and losses adding up to almost $120 billion per year. There are approximately 50,000 foreign species and the number is increasing. About 42% of the species on the Threatened or Endangered species lists are at risk primarily because of alien-invasive species.

Potential economic damage from introduction of Brown Tree Snakes, Boiga Irregularis (Reptilia: Colubridae), to the Islands of Hawaii

Gebhardt, Karen

Kirkpatrick, Katy N.

Shwiff, Stephanie A.

Shwiff, Steven S.

The Brown Tree Snake (Boiga irregularis) has caused ecological and economic damage to Guam, and the snake has the potential to colonize other islands in the Paci c Ocean. This study quanti es the potential economic damage if the snake were translocated, established in the state of Hawaii, and causing damage at levels similar to those on Guam. Damages modeled included costs of medical treatments due to snakebites, snake-caused power outages, and decreased tourism resulting from effects of the snake. Damage caused by presence of the Brown Tree Snake on Guam was used as a guide to estimate potential economic damage to Hawaii from both medical- and power outagerelated damage. To predict tourism impact, a survey was administered to Hawaiian tourists that identi ed tourist responses to potential effects of the Brown Tree Snake. These results were then used in an input-output model to predict damage to the state economy. Summing these damages resulted in an estimated total potential annual damage to Hawaii of between $593 million and $2.14 billion. This economic analysis provides a range of potential damages that policy makers can use in evaluation of future prevention and control programs.

Economics of Harmful Invasive Species: A review

Gren, Ing-Marie

Marbuah, George

McKie, Brendan

The purpose of this study is to review theoretical and empirical findings in economics with respect to the challenging question of how to manage invasive species. The review revealed a relatively large body of literature on the assessment of damage costs of invasive species; single species and groups of species at different geographical scales. However, the estimated damage costs show large variation, from less than 1 million USD to costs corresponding to 12% of gross domestic product, depending on the methods employed, geographical scale, and scope with respect to inclusion of different species. Decisions regarding optimal management strategies, when to act in the invasion chain and which policy to choose, have received much less attention in earlier years, but have been subject to increasing research during the last decade. More difficult, but also more relevant policy issues have been raised, which concern the targeting in time and space of strategies under conditions of uncertainty. In particular, the weighting of costs and benefits from early detection and mitigation against the uncertain avoidance of damage with later control, when the precision in targeting species is typically greater is identified as a key challenge. The role of improved monitoring for detecting species and their spread and damage has been emphasized, but questions remain on how to achieve this in practice. This is in contrast to the relatively large body of literature on policies for mitigating dispersal by trade, which is regarded as one of the most important vectors for the spread of invasive species. On the other hand, the literature on how to mitigate established species, by control or adaptation, is much more scant. Studies evaluating causes for success or failure of policies against invasive in practice are in principal non-existing.

Learning-by-catching: Uncertain invasive-species populations and the value of information

Burnett, Kimberly

D'Evelyn, Sean T.

Roumasset, James A.

Tarui, Nori

This paper develops a model of invasive species control when the species population size is unknown. In the face of an uncertain population size, a resource managers species-control efforts provide two potential bene ts: (1) a direct bene t of possibly reducing the population of invasive species, and (2) an indirect bene t of information acquisition (due to learning about the population size, which reduces uncertainty). We provide a methodology that takes into account both of these bene ts, and show how optimal management decisions are altered in the presence of the indirect bene t of learning. We then apply this methodology to the case of controlling the Brown Treesnake (Boiga irregularis) on the island of Saipan. We nd that the indirect bene tthe value of information to reduce uncertaintyis likely to be quite large.

Taking the sting out of the Little Fire Ant in Hawaii

Lee, Donna J.

Leung, PingSun

Motoki, Michael

Nakamoto, Stuart T.

Vanderwoude, Casper

Inthe1990's,LittleFireAnts(LFAs)founditswaytotheislandofHawaii,mostlikelytravelingwithashipmentof potted plantsfrom Florida.These plants weresubsequentlysold toconsumers along theeastcoast of theIsland, alongwithLittleFireAntcolonieslivinginthepottingmedium.LFAisnowthrivingandcontinuestospread.Fifteenyearsaftertheinitialdetectionin1999,LFAhasspreadtoover4000locationsontheislandofHawaiiandhas beenfoundinisolatedlocationsonKauai,Maui,andOahuIslands.Currenteffortsareexpectedtocontaintheinfestations on the otherislands but signi cant additional investment isneeded tohalt therapid spread of LFA on the island of Hawaii. Increased management expenditures can suppress infestations; reduce spread between sectors; and decrease long-term management costs, damages, and stings.| Animmediateexpenditureof$8millioninthenext23yearsplusfollow-upprevention,monitoring,andmitigation treatments will yield $1.210 billion in reduced control costs, $129 million in lowered economic damages, 315 million fewer human sting incidents, and 102 million less pet sting incidents over 10 years.| Over35years,thebene tsinclude$5.496billioninreducedcontrolcosts,$538millionlesseconomicdamages, 2.161 billion fewer human sting incidents, and 762 million fewer pet sting incidents.

Prevention, Eradication and Containment of Invasive Species: Illustrations from Hawaii

Burnett, Kimberly

Kaiser, Brooks

Pitafi, Basharat A.

Roumasset, James

Invasive species change ecosystems and the economic services such ecosystems provide. Optimal policy will minimize the expected damages and costs of prevention and control. We seek to explain policy outcomes as a function of biological and economic factors, using the case of Hawaii to illustrate. First, we consider an existing invasion, Miconia calvescens, a plant with the potential to reduce biodiversity, soil cover, and water availability. We then examine an imminent threat, the potential arrival of the Brown Treesnake (Boiga irregularis). The arrival of the snake to Guam has led to native bird extirpations, power outages, and health costs.

Distribution, relative abundance, and habitat relationships of landbirds in the Vava'u group, Kingdom of Tonga / by David W. Steadman and Freifield, Holly B.

Available Online

Freifield, Holly B.

Steadman, David W.

We assessed the distribution, relative abundance, and habitat preferences of the 12 indigenous, resident species of landbirds that survive in the Vavau Group, Kingdom of Tonga. We surveyed 16 islands, 10 of which are previously unmentioned in ornithological literature. The islands vary in land area (0.02-96 kn?), habitat composition, elevation (20- 215 m), and distance (O-lo.1 km) from the largest island of Uta Vavdu. We conducted point counts along transects on 14 of the islands, and placed each count location into one of five habitat categories. Of the 11 species of landbirds that are widespread and at least locally common, 7 (Purple-capped Fruit-Dove Ptilinopus porphyraceus, Pacific Pigeon Ducula pacijca, Common Barn-Owl Tyto alba, White-rumped Swiftlet Collocalia spodiopygia, Collared Kingfisher Halcyon chloris, Polynesian Tiiller Lalage maculosa, Polynesian Starling Aplonis tabuensis) certainly or probably occur on each of the 16 islands. One species (West Polynesian Ground-Dove Gallicolumba stairii) is extremely rare (one small population on one island). Three species that we did not record (Many-colored Fruit-Dove Ptilinopus perousii, Blue-crowned Lorikeet Vini australis, Fiji Shrikebill Clytorhynchus vitiensis) probably have been extirpated from Vavau. The species richness and relative abundance of landbirds on islands in Vavau are affected more by deforestation and other human activities than by island area, elevation, or isolation.

Pig Trap - Model CEN NC - Rope snare (Brochure) / Piége á cochons - Modéle CEN - Collet-corde

Island and Ocean Ecosystems, BRB

Conservatoire d'espaces Naturels (CEN)

Brochure (French & English) on setting up pig traps.

Awareness Strategy - Management of Water Lettuce (Pistia stratiotes) Aquatic plant

Island and Ocean Ecosystems, BRB

Available Online

Divison of Environment and Conservation

Water lettuce is a free floating aquatic plant in rosettes of green leaves, rosettes occuring singly or connected to others by short stolons whose origins are uncertain. It forms large, dense floating mats. The plant can adapt to life in ponds, dams, lakes and quiet areas of rivers and streams, but cannot withstand salt water. Still continue with observation whether it is to survive in winter.

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