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The Ecology of Rodents in the Tonga Islands
BRB
Available Online

Twibell, John

The influence on crop damage of Rattus norvegicus, Rattus rattus, and the native Polynesian rat, Rattus exulans, was studied during the establishment of a rat control program for the Tongan Department of Agriculture in 1969. This was the first long-term study of Tongan rodents. Previous scientific literature on Tongan mammals is very sparse. The Kingdom of Tonga, or Friendly Islands, consists of approximately 150 small islands with a combined area of about 256 square miles at lat 21 0 S. The majority of these islands are composed of raised coral limestone ; however, there is a row of six volcanic islands on Tonga's western border. Tongatapu, the location of the government center, is the largest and most important island. The Ha'apai island group lies 80 miles north of Tongatapu, and 150 miles north is the Vava'u group. Fiji is 420 nautical miles east and Samoa is 480 miles north. The climate is tropical and is influenced seasonally by trade winds. Since Captain Cook's first visit in 1773, Western civilization has brought trade, missionaries, and perhaps rats to Tonga. With this shipping came numerous introduced plants and animals. The arrival dates for the common rat, Rattus norvegicus, and the "European" roof rat, Rattus rattus, are not known, but are believed to be more recent, probably since the increase of regular shipping trade and the construction of wharves. Presently rodents account for approximately 20 percent of the agricultural losses and $50,000 worth of economic loss each year (Twibell, unpublished). This is a conservative estimate based on damage counts and observation. In some areas rats destroy or damage up to 50 percent of the coconuts, which represent the main economic crop in Tonga. THE INFLUENCE on crop damage of Rattus norvegicus, Rattus rattus, and the native Polynesian rat, Rattus exulans, was studied during the establishment of a rat control program for the Tongan Department of Agriculture in 1969. This was the first long-term study of Tongan rodents. Previous scientific literature on Tongan mammals is very sparse. The Kingdom of Tonga, or Friendly Islands, consists of approximately 150 small islands with a combined area of about 256 square miles at lat 21 0 S. The majority of these islands are composed of raised coral limestone ; however, there is a row of six volcanic islands on Tonga's western border. Tongatapu, the location of the government center, is the largest and most important island. The Ha'apai island group lies 80 miles north of Tongatapu, and 150 miles north is the Vava'u group. Fiji is 420 nautical miles east and Samoa is 480 miles north. The climate is tropical and is influenced seasonally by trade winds. Since Captain Cook's first visit in 1773, Western civilization has brought trade, missionaries, and perhaps rats to Tonga. With this shipping came numerous introduced plants and animals. The arrival dates for the common rat, Rattus norvegicus, and the "European" roof rat, Rattus rattus, are not known, but are believed to be more recent, probably since the increase of regular shipping trade and the construction of wharves. Presently rodents account for approximately 20 percent of the agricultural losses and $50,000 worth of economic loss each year (Twibell, unpublished). This is a conservative estimate based on damage counts and observation. In some areas rats destroy or damage up to 50 percent of the coconuts, which represent the main economic crop in Tonga.
Potential impact of climate change on the distribution of six invasive alien plants in Nepal.
BRB
Available Online

Shrestha Uttam Babu

The biological invasions have been increasing at multiple spatial scales and the management of invasive alien species is becoming more challenging due to confounding effects of climate change on the distribution of those species. Identification of climatically suitable areas for invasive alien species and their range under future climate change scenarios areessentialfor long-term management planningofthesespecies. Using occurrence data of six of the most problematic invasive alien plants (IAPs) of Nepal (Ageratum houstonianum Mill., Chromolaenaodorata (L.) R.M. King & H. Rob., Hyptis suaveolens (L.) Poit., Lantana camara L., Mikania micrantha Kunth, and Parthenium hysterophorus L.), we have predicted their climatically suitable areas across the country under the current and two future climate change scenarios (RCP 4.5 scenarios for 2050 and 2070). We have developed an ensemble of eight different species distribution modelling approaches to predict the location of climatically suitable areas. Under the current climatic condition, P. hysterophorus had the highest suitable area (18% of the total country’s area) while it was the lowest for M. micrantha (12%). A predicted increase in the currently suitable areas ranges from 3% (M. micrantha) to 70% (A. houstonianum) with the mean value for all six species being 29% under the future climate change scenario for 2050. For four species (A. houstonianum, C. odorata, H.suaveolens and L. camara), additional areas at elevations higher than the current distribution will provide suitable habitat under the projected future climate. In conclusion, all six IAPs assessed are likely to invade additional areas in future due to climate change and these scenarios need to be considered while planning for IAPs management as well as climate change adaptation.
Global rise in emerging alien species results form increased accessibility of new source pools
Biodiversity Conservation, BRB
Available Online

Alain, Roques

,

Alexander, Mosena

,

Andrew M, Liebhold

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Barbara, Tokarska-Guzik

,

Benoit, Guenard

,

Bernd, Blasius

,

Bernd, Lenzner

,

Cesar, Capinha

,

Charlotte, E Causton

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Darren, F Ward

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David, Pearman

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Dietmar, Moser

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Eckehard, G Brockerhoff

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Ellie, E Dyer

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Evan, PEconomo

,

Franz, Essl

,

Giuseppe, Brundu

,

Hanno, Seebens

,

Heinke, Jager

,

Helen E, Roy

,

Ingolf, Kuhn

,

Jan, Pergl

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John, Kartesz

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Jonathan, M Jeschke

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Julissa, Rojas-Sandoval

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Katerina, Stjerova

,

Kevin Walker

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Laura, Celesti-Grapow

,

Marc, Kenis

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Margarita, Arianoutsou

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Mark, van Kleunen

,

Marten, Winter

,

Michael, Ansong

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Misako, Nishino

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Nicol, Fuentes

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Petr, Pysek

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Philip, E Hulme

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Piero, Genovesi

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Riccardo, Scalera

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Shyama, Pagad

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Silvia, Rossinelli

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Stefan, Dullinger

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Stefan, Schindler

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Stephanie, Rorke

,

Sven, Bacher

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Takehiko, Yamanaka

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Tim M, Blackburn

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Wayne, Dawson

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Wolfgang, Nentwig

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Wolfgang, Rabitsch

Our ability to predict the identity of future invasive alien species is largely based upon knowledge of prior invasion history. Emerging alien species—those never encountered as aliens before—therefore pose a significant challenge to biosecurity interventions worldwide. Understanding their temporal trends, origins, and the drivers of their spread is pivotal to improving prevention and risk assessment tools. Here, we use a database of 45,984 first records of 16,019 established alien species to investigate the temporal dynamics of occurrences of emerging alien species worldwide. Even after many centuries of invasions the rate of emergence of new alien species is still high: One-quarter of first records during 2000–2005 were of species that had not been previously recorded anywhere as alien, though with large variation across taxa. Model results show that the high proportion of emerging alien species cannot be solely explained by increases in well-known drivers such as the amount of imported commodities from historically important source regions. Instead, these dynamics reflect the incorporation of new regions into the pool of potential alien species, likely as a consequence of expanding trade networks and environmental change. This process compensates for the depletion of the historically important source species pool through successive invasions. We estimate that 1–16% of all species on Earth, depending on the taxonomic group, qualify as potential alien species. These results suggest that there remains a high proportion of emerging alien species we have yet to encounter, with future impacts that are difficult to predict.
Ecological and socioeconomic impacts of invasive alien species in island ecosystems.
Biodiversity Conservation, BRB
Available Online

Jamie K Reaser ? Laura A Meyerson ? Quentin Cronk ? Maj De Poorter

Minimizing the impact of invasive alien species (IAS) on islands and elsewhere requires researchers to provide cogent information on the environmental and socioeconomic consequences of IAS to the public and policy makers. Unfortunately, this information has not been readily available owing to a paucity of scientific research and the failure of the scientific community to make their findings readily available to decision makers. This review explores the vulnerability of islands to biological invasion, reports on environmental and socioeconomic impacts of IAS on islands and provides guidance and information on technical resources that can help minimize the effects of IAS in island ecosystems. This assessment is intended to provide a holistic perspective on island-IAS dynamics, enable biologists and social scientists to identify information gaps that warrant further research and serve as a primer for policy makers seeking to minimize the impact of IAS on island systems. Case studies have been selected to reflect the most scientifically-reliable information on the impacts of IAS on islands. Sufficient evidence has emerged to conclude that IAS are the most significant drivers of population declines and species extinctions in island ecosystems worldwide. Clearly, IAS can also have significant socioeconomic impacts directly (for example human health) and indirectly through their effects on ecosystem goods and services. These impacts are manifest at all ecological levels and affect the poorest, as well as richest, island nations. The measures needed to prevent and minimize the impacts of IAS on island ecosystems are generally known. However, many island nations and territories lack the scientific and technical information, infrastructure and human and financial resources necessary to adequately address the problems caused by IAS. Because every nation is an exporter and importer of goods and services, every nation is also a facilitator and victim of the invasion of alien species. Wealthy nations therefore need to help raise the capacity of island nations and territories to minimize the spread and impact of IAS.