Published in 2011
Research articles
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Tamene Yohannes, Tesfaye Awas and Sebsebe Demissew
Survey and documentation of the potential and actual invasive alien plant species and other biological threats to biodiversity in Awash
National Park, Ethiopia (pp 3-14) |
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The study was conducted at the Awash National Park (ANP) Ethiopia, to document Invasive Alien Species (IAS) and to assess the spread of Prosopis juliflora (Sw.) DC.
A total of 64 sample plots were laid systematically along the altitudinal gradient of 750 to 1916 m. Potential IAS were recorded. IAS which may threaten biodiversity
of the park includes species such as Prosopis juliflora, Parthenium hysterophorus L., Cryptostegia grandiflora Roxb. ex R. Br. ,
Parkinsonia aculeata L., Senna occidentalis (L.) Link, Datura ferox L. and Xanthium strumarium L. Except P. juliflora and
P. hysterophorus, all others were not recorded in Ethiopia as IAS. P. juliflora was recorded in three plots with cover of 1% to 10%.
P. juliflora was also found spread in different parts of the park particularly following the route of cattle movement. P. hysterophorus was recorded
in and around nine sample plots. Plot 46, 47 and 48 were highly infested by P. hysterophorus which covered more than 60, 70 and 80% of the ground layer respectively.
C. grandiflora was recorded in 11 plots with cover ranging from 1% to 35%. In view of all the natural as well as anthropogenic threats to the biodiversity
of the Park, the ANP is at high risk. The rich biodiversity needs immediate management intervention.
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Jiselle A. Bakker, S. Christine Paetzold, Pedro A. Quijón and Jeffrey Davidson
The use of food grade oil in the prevention of vase tunicate fouling on mussel aquaculture gear (pp 15-25) |
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Current mitigation strategies against invasive tunicates on mussel aquaculture gear in Prince Edward Island concentrate on labour-intensive and costly fouling removal.
Instead of removal, this study focused on preventing the settlement of the vase tunicate Ciona intestinalis and other fouling organisms by applying a layer
of food grade oil to gear prior to recruitment. Laboratory tests established the adherence and persistence of shortening, a food grade oil with a melting point
exceeding ambient water temperatures, to rope and mussels. In situ tests showed that shortening decreased C. intestinalis weight and abundance on buoys,
spat collector ropes and collector plates but not on mussel socks. Fouling by algae and other tunicates was significantly reduced on most substrates. There were no
detrimental effects of shortening treatment on mussel length and abundance on mussel socks, but total mussel weight was significantly lower on shortening-treated socks.
Shortening treatment did not significantly affect mussel spat settlement on spat collector ropes, but further evaluation is required. Overall, shortening application
has considerable potential for reducing tunicate and other fouling, particularly on buoys.
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Marianne Parent, S. Christine Paetzold, Pedro A. Quijón and Jeffrey Davidson
Perforation with and without vinegar injection as a mitigation strategy against two invasive tunicates, Ciona intestinalis and Styela clava (pp 27-38) |
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Ciona intestinalis and Styela clava, two nuisance species for Prince Edward Island’s blue mussel industry, were treated with individual perforations
using nails or hypodermic needles. Other treatments using the same species included simultaneous perforations using perforation devices with low, medium and high needle
density, either with or without vinegar injections. Mortality levels estimated for all ranges of individual perforations were significantly higher than mortality levels
estimated in control groups during treatments conducted at laboratory facilities. Mortality of C. intestinalis reached 100% for 60 individual perforations or
injection of 0.05 mL of vinegar. In S. clava, 100 individual perforations resulted in 100% mortality. Two applications of the high-density perforation device
resulted in 80% mortality of C. intestinalis. During field testing, two applications of the same high-density needle device did not significantly decrease
C. intestinalis wet weight, regardless of the addition of vinegar. The field applicability of perforation upon tunicates fouling mussel socks was at least
in part limited by the uneven surface created by the mussels and the possible inhibition of bacterial growth caused by low water temperatures. Perforation and vinegar
injection showed to be successful in laboratory trials and should be further studied with different perforation devices under field conditions.
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Jamie A. Copsey, Graham Shelbourne, Rachael Grice, Martine Goder, Steeves Buckland, Zayd Jhumka, Vimul Nundlaul, Carl Jones and Nik Cole
Possible control of introduced giant African land snails (Achatina spp.) by the reintroduced endemic skink Leiolopisma telfairii, Ile aux Aigrettes,
Mauritius (pp 39-45) |
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The giant African land snail (Achatina fulica) is one of the world’s worst invasive species, out‐competing endemic snails, consuming native
vegetation and potentially altering nutrient cycles. Attempts to eradicate the snail from islands have only been successful with incipient populations.
We present correlative evidence that native island predators may act as an effective control agent for the snail. In 2000 a population of between 37,300
and 45,100 African land snails was estimated on the 26ha nature reserve island of Ile aux Aigrette, Mauritius. Between 2006 and 2007, 260 endemic Telfair’s
skink Leiolopisma telfairii were reintroduced to the reserve. Snail population surveys in 2008 and 2009 showed that the introduced snail population
had declined to 5,569 (±3,630) and 6,871 (±5,379), respectively. Previous studies showed that the introduced snails were selective over other invertebrate prey items.
We suggest that predation by the endemic skink has been an important causal factor behind the snail population decline.
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Scott Hardin, Ellen Donlan, Marsha Ward and Dave Eggeman
Attempted eradication of Porphyrio porphyrio Linnaeus in the Florida Everglades (pp 47-55) |
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Porphyrio porphyrio (Fulica porphyrio Linnaeus) was reported to the South Florida Water Management District in a Water Conservation Area and in
constructed wetlands in the Everglades in 2006. A rapid assessment, including casual observations and surveys of land managers, indicated a limited number
of P. porphyrio (~300 birds) was present, and an eradication attempt was initiated. From 2006 – 2008, more than 3100 P. porphyrio were killed by
shotgun from airboats during 73 hunts, suggesting the initial population assessment was severely underestimated. After removing nearly 1500 P. porphyrio
in 2008, we concluded that eradication was not possible. Failure of this eradication attempt is attributed to P. porphyrio’s affinity with dense emergent
vegetation, which greatly limited shooting effectiveness. Further, the failed eradication underscores the importance of a reporting network to improve early detection
and the chance to eliminate naturalized or feral populations of non‐native species.
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Deniz Innal
Distribution and impacts of Carassius species (Cyprinidae) in Turkey: a review (pp 57-68) |
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Biological invasions have caused considerable disruption to native ecosystems throughout the world through predation, habitat alteration, competition and
hybridisation with native species and introduction of diseases or parasites. Species of the genus Carassius [C. auratus (Linnaeus, 1758),
C. carassius (Linnaeus, 1758) and C. gibelio (Bloch, 1782)] were transported to numerous inland water bodies throughout Turkey. Species are
now considered a threat factor for native species. The purpose of this study is to review the current distribution and ecological impacts of species
in the inland waters of Turkey.
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Ayana Etana, Ensermu Kelbessa and Teshome Soromessa
Impact of Parthenium hysterophorus L. (Asteraceae) on herbaceous plant biodiversity of Awash National Park (ANP), Ethiopia (pp 69-80) |
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This study was conducted in Awash National Park (ANP), East Shewa Zone of Oromia National Regional Sate, Ethiopia, aimed at determining the impact of parthenium weed
(Parthenium hysterophorus L.) on herbaceous diversity. A transect belt of 13.5 km * 0.10 km of parthenium weed infested land was identified for the determination
of the impact. Four quadrats were purposively laid every 250 m interval two for infested and two for non-infested each from both sides of the road and a total of 216
quadrats of 2 m x 2 m (4 m2) were considered. A total of 91 species were identified from which five of them were out of the quadrats. All species were categorized into
21 families, from which Poaceae and Fabaceae shared about 40%. The species in the non-infested quadrats were found to be more diverse and even when compared to those
of the infested quadrats. Infested quadrats were found to be more abundant and dominant. Tetrapogon tenellus was found the dominant specie in the non-infested quadrats
while Parthenium hysterophorus was found dominant in the infested followed by T. tenellus. There was no statistically significant difference between the total
stand crop biomass of the infested and non-infested. Parthenium weed have been found creating great challenge on herbaceous plant diversity of ANP.
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Jara Andreu and Montserrat Vilà
Native plant community response to alien plant invasion and removal (pp 81-94) |
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Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental
managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community
back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-invaded and
removal sites to quantify invaders’ impacts and native plant recover after their removal. We also conduct a meta-analysis to quantitatively evaluate the impacts of plant
invaders and the consequences of their removal on the native plant community, across a variety of ecosystems around the world. Our results that invasion by alien plants
is responsible for a local decline in native species richness and abundance. Our analysis also provides evidence that after removal, the native vegetation has the potential
to recover to a pre-invasion target state. Our review reveal that observational and experimental approaches are rarely used in concert, and that reference sites are scarcely
employed to assess native species recovery after removal. However, we believe that comparing invaded, non-invaded and removal sites offer the opportunity to obtain scientific
information with relevance for management.
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Mihails Pupins and Aija Pupina
First records of 5 allochthonous species and subspecies of Turtles (Trachemys scripta troostii, Mauremys caspica, Mauremys rivulata,
Pelodiscus sinensis, Testudo horsfieldii) and new records of subspecies Trachemys scripta elegans in Latvia (pp 95-107) |
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The aim of the research was to investigate the presence of allochthonous species of turtles in the nature of Latvia, as well as to withdraw them from the nature
according to the "Plan on protection of Emys orbicularis in Latvia", officially approved by the Latvian Ministry of Environment (Pupiņš & Pupiņa 2007a). The methods
of the research were: 1) information campaign and survey; 2) interviews with inhabitants; 3) field expeditions; 4) laboratory study of viability of found turtles.
In course of research, five new allochthonous species and subspecies of the turtles were recorded for the first time, and new data were obtained about finding
Trachemys scripta elegans in the nature of Latvia. Most of the registered animals (80%) were removed from the nature. Since allochthonous turtles get
there in the result of escape from pet-lovers and, apparently, illegal introduction into nature by their owners, education of population is of great importance.
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