Mammalian Pest Report - Literature review Example

Mammalian Pest Report s Mammalian Pest Report Abdullah Hamzi Part One :Literature Review Introduction to Mammalian Pests In New Zealand Invasive species pose a threat to the biodiversity of New Zealand. Mammalian pests such as possums, rats and stoats are of major concern today since they lead to environmental degradation and species extinction. New Zealand has focused its research on developing novel strategies to tackle the problem of mammalian pests. Major Pests In New Zealand Some of the most destructive pests include possums, rats and stoats. Possums Possums are an introduced species in New Zealand. Scientifically known as Trichosurus vulpecula. They were brought in from Australia, and introduced to Southland in 1837 (TEARA, 2014). Primarily introduced for the fur trade, the species established itself and harmed the local environment. Today there are more than 10 million possums in Northland alone (Northland Regional Council, 2014). The population has increased mostly owing to the non-existence of any natural predators of this pest. Studies have been done to understand the impact of possum infestation and fecal analysis of the pests has shown evidence of bird predation especially native forest birds. Possums are a major threat to local birds such as the kokako and kukupa (Landcare Research, 2014). Possums are also a major threat to the vegetation of New Zealand. It is estimated that possums feed on almost 21,000 tons of vegetation every single day (Landcare Research, 2014). Stoats Stoats are members of the Mustelid family which also includes weasels and ferrets. By 1880, New Zealand, had already suffered problems from harmful pests such as rabbits and hares. Stoats were imported from Britain and introduced in New Zealand as biological control for rabbits. Today, stoats are widespread in most parts of New Zealand and have themselves become mammalian pests. They are extremely adaptable to any living conditions where they may find food (Dept. Of Conservation Te Papa Atawhai, 2014). Stoats are a major concern since they are a natural predator of several native birds of New Zealand such as the bush canary (yellow head) and kaka. They not only destroy the nests of the birds but also feed on their eggs and nestlings. This has led to sharp decline in the population of these forest birds. Rats In New Zealand three kinds of rats- the common rat, Pacific rat and kiore rat have been introduced. Kiore rats were introduced by the Maori as source of food. However today, rats pose a major threat to the biodiversity of New Zealand since they feed on birds, bird eggs and other small invertebrates such as lizards. An Emerging Strategy Use of chemicals to manage pests has been proved to be efficient. In 2011, an efficient and humane toxicant Para-aminopropiophenone was introduced. This chemical induces lethargy and sleep in the pests before their death and causes negligible pain (Blackie et al, 2013). Since methods of control such as bait trapping or biological control have so far proved futile, development of such humane intoxicants are emerging as efficient strategies to tackle the pest problem. Part Two: Pest Control Programmes Site introduction Maungatautari Ecological Island The Maungatautari Ecological reserve is located in South Waikato and managed by the Maungatautari Ecological trust. It is considered the largest ecological island of New Zealand. The main aim of the management team is to remove all kinds of introduced species from Maungatautari and reintroduce native birds and plant species to ensure their existence without any kind of interference (Maungatautari Ecological Island Trust, 2010). The ecological island is fenced enclosing close to 3400 hectares of predator free area. The Island’s main feature is its restoration project which is an endeavor to re-introduce certain indigenous species to the area. After complete eradication of mammalian pests, native birds such as the kaka, kiwi and robin have been successfully re-established. Tikitapu Scenic Reserve The Tikitapu Scenic Reserve is an indigenous forest located in the district of Rotorua to the north and east side of Lake Tikitapu. The reserve is managed by the Department of Conservation. The reserve aims to restore indigenous flora and fauna of the area. The main objective of the reserve is the protection of the native mistletoe and increase the population of native birds which helps in mistletoe pollination. Pest management Programmes The vision of the Maungatautari Ecological Island Trust or MEIT in terms of pest management has been to completely eradicate 14 species of mammals. The Maungatautari Ecological Island, has been safeguarded since its inceptions by the 47 kilometer long pest-proof fence. The island’s trust was primarily responsible for initiation of the pest-proof fencing which was the first step in pest management. The fence is constructed of stainless steel mesh and the rolled hood prevents animals from climbing thereby preventing any pest animals from crossing the boundary and entering the island area. In 2004, using staff and volunteers a pre-eradication exercise was initiated and only rats were detected. In the same year, baits laced with brodifacoum were dispersed aerially to control rats. In the years 2005 and 2006, areas were cleared to make way for tracks and monitoring tunnels were installed which made detection of pests easier. In 2006 and 2008 again baits laced with brodifacoum were used. The use of baits was enhanced by shooting, trapping and ground-based poisoning of pests. By 2007 most pests were eradicated, while in 2008 hedgehogs and in 2009 goats and rats were completely eradicated (MEIT, 2010). Studies have shown that after the eradication of pests, a dramatic increase in the Orthoptera population has been detected (Watts et al, 2011). However, to this day area surveillance is carried out frequently using electronics and monitoring by volunteers. The issues that the management needs to contend with are proper maintenance of the fencing and frequent monitoring. Today only rabbits, hares and mice are left. In order to control pests the use of brodifacoum has been phased out and diphacinone is used. Tikitapu Scenic Reserve is protected against pests by programs undertaken by the Tipitaku Forest and Bird Care Group. The area is threatened mostly by possums and rats and therefore all management strategies are focused upon detection and eradication of these pests. In 2003, a pest control operation was conducted using bait stations. In 2011, 150 bait stations using Pindone cereal baits and Feratox capsules were used to reduce pest numbers. In 2013, an updated pest management program was conducted and it was observed that Pindone bait without addition of Feratox failed to reduce the rat population and therefore in 2014 it was planned to use the previous mix of both the chemicals in the baits. Recently, in 2014 the Tikitapu Working Bee program was initiated where baits were laid and the post-bait monitoring is due by the end of October (Rotorua Branch newsletter, 2014). Figure: bait stations for Possums and Rats Having seen both the management programs, we can identify that the sites have different problems. While today Maungatautari is infested with rabbits, hares and rats, Tikitapu has the problem of possums and rats. Both have different strategies to tackle the problems as well. The main difference being Maungatautari Island fenced the entire area and conducts regular checks while Tikitapu does not have a properly fenced area and monitoring is done annually. The main similarity between the two is that the management of both the sites has sought the help of chemicals for pest management. Part Three: A Report To The Tikitapu Pest Control Group Given below is the map showing the bait stations laid especially for rat infestations. Data Presentation A graphical representation has been prepared using the comprehensive data provided for the years of pest tracking both before and after baiting. The graphs have been made in a yearly basis showing the kind of pest tracked and the number of tunnels in which they were tracked giving an estimation of the pest’s distribution.For the possum population we see distribution of possums both before and after the baiting was laid. A similar graph has been generated for the rat population showing the number of rats before and after baiting was done. For the graph regarding toxin usage to control the pests has been plotted showing the different types of toxins used for the pests in each year from 2004 to 2014. Graph For Year wise Toxin Efficacy to Control Rats Graph For Year Wise Toxin Efficacy To Control Possums Analysis of The Data And Advice For Management On analysing the data it can be seen that the outcomes for rats and possums are not the same. The population abundance pre and post baiting is different between the years 2011-2014 during which baiting was used for all pests. In 2011 possums did not show much difference in he total population before and after baiting. However, the rat population had increased post baiting showing that the pesticide used in 2011 i.e. Pinodone and Ferotox pellets was more effective on marsupials. Since in 2012, no pest control was done no comparative data could be generated. In 2013, the rat population decreased post-baiting but the population of Possums had increased. This indicates that the Pinadone and Ferotox strikers were more effective on rats than on marsupials. In 2014, the populations of all pests decreased drastically which indicated that the pesticide used in 2014 i.e. Pinadone and Feratox pellets used was efficient. It needs to be noted that these same pellets were not quite as effective in 2011 since the time the baits were laid was different. Therefore it is recommended the reserve management needs to use the pellet form of Pinadne and Feratox. To ensure the most comprehensive control of pest population the baits need to be laid in-between August and September. The data representation shows that the current pest control methods are effective enough at minimizing the pest population. However the group needs to consider that baiting should be done every year to prevent populations from establishing. This is evident since after 2012 during which no baiting was done, the rat population increased. Additionally in 2013 even after baiting was done the population could not managed and the numbers stayed somewhat the same. Therefore, baiting operations should not be suspended. Also in 2009 the Pinadone and Feratox baits were laid down for 4 months and it gave the most efficient results and helped control the rat population. However for possums the same baits can be laid for 2 months and yield appreciable, The populations of some pests such as possums are patchy in nature. The group could lay traps to control the possum population in the reserve. The population of rats was fairly even and is seen from the map. REFERENCES Blackie,H.M.et al. (2013). Innovative developments for long-term mammalian pest control.Pest . Management Science. Retrieved from http://www.cawthron.org.nz/media_new/publications/pdf/2013_10/Blackie_et_al_2013_1.pdf on 16 October, 2014 Department of Conservation Te Papa Atawhai. (2014).Animal pests- Stoats. Retrieved from http://www.doc.govt.nz/conservation/threats-and-impacts/animal-pests/animal-pests-a-z/stoats/ on 16 October 2014. Landcare Research.Effect of possum on native animals.(2014). Retrieved from http://www.landcareresearch.co.nz/__data/assets/pdf_file/0007/42001/possum_effects_on_native_animals.pdf Landcare Research. (2014).Effect of Possum on native vegetation. Retrieved from http://www.landcareresearch.co.nz/__data/assets/pdf_file/0006/42000/possum_native_vege.pdf on 15 th October, 2014. Mangatautari Island Trust.(2010).Retrieved from http://www.maungatrust.org/ on 16 october, 2014. Northland Regional Council. (2014). Possums and other pests.Retrieved from http://www.nrc.govt.nz/For-Schools/School-information-packs/Possums-and-pests/ on 16 October, 2014. Rotura Branch Newletter.(2014).Retrieved from http://www.forestandbird.org.nz/files/publication_attachments/FB%20Newsletter%20July%202014.pdf on 16 october, 2014. TEARA.(2014). Introduced Animal pests-Possums. Retrieved from http://www.teara.govt.nz/en/introduced-animal-pests/page-2 on 16 October, 2014. Watts,C.H. et al.(2011). Dramatic increases in weta (Orthoptera) following mammal eradication on Maungatautari – evidence from pitfalls and tracking tunnels.New Zealand Journal of Ecology, 35 (3), 261-272. Retrieved from http://newzealandecology.org/nzje/2991.pdf on 15 October, 2014. Read More