Providing evidence to improve practice

The journal, Conservation Evidence

Our online journal publishes research, monitoring results and case studies on the effects of conservation interventions. All papers include some monitoring of the effects of the intervention and are written by, or in partnership with, those who did the conservation work. It includes interventions such as habitat creation, habitat restoration, translocations, reintroductions, invasive species control, and education or integrated conservation development programmes, from anywhere around the world.

A volume is created each year with peer-reviewed papers published throughout the year. We now accept Short Communications as well as standard papers.

Special issues contain new papers on a specific topic.

Virtual collections collate papers published in the journal on specific topics such as management of particular groups of species.

To search for papers on a specific topic within the journal select 'Advanced search' on the Home page, enter your keyword(s) and within the Source box type: "conservation evidence".

Volume 7



Small cow-wheat Melampyrum sylvaticum, a nationally scarce annual identified as a priority species in the UK Biodiversity Action Plan, was the focus of a translocation attempt aiming to establish new populations within the extent of its former Scottish range. Seeds were collected (from wild Scottish
populations) in three phases (in the years 2005, 2006 and 2008) and sown at six receptor sites where the species was absent but habitat seemed suitable. Each phase used increasing numbers of seed after the results of the first phase (89 to 103 seeds sown per site) suggested that many more than 100 seeds are needed to establish the species (at least in the short-term) at a site. Comparisons of the suitability of seed from three different wild populations showed that one resulted in higher germination rates. This donor population was associated with environmental conditions more similar to those at the receptor sites than those of the other donors. Receptor sites also differed in their suitability; those that were climatically and edaphically more similar to sites supporting wild populations appear to be more favourable to M.sylvaticum longer-term survival. Together, these can be seen to suggest that future seed translocation should be to sites that are ecologically similar to the donor population and within sites that fall into the cooler and wetter range of environmental conditions currently supporting Scottish populations of M.sylvaticum.

A public education and citizen science programme was developed to improve data collection on incidences of deliberate killing of snakes and to reduce unfounded killing of snakes in human dominated landscapes of Kerala, southwest India. During 2003-2009, citizen scientists recorded 278 direct human kills and more than 200 kills of snakes by vehicular collision, agricultural practices and attack by pets. Participants managed to prevent killing of 276 non-venomous snakes (of 14 taxa). The non-venomous Travancore wolf snake Lycodon travancoricus (a batesian mimic of the deadly venomous Indian krait Bungarus caeruleus) was the species that benefited most of the programme. In addition, the conservation education programme (highlighting ecosystem services of reptiles) resulted in positive attitudinal changes among local people towards the conservation of snakes and general biodiversity of the region.

Mass trapping successfully achieved elimination of black rat Rattus rattus on Feno islet (1.6 ha), Terceira island (Azores archipelago), thus enabling roseate terns Sterna dougallii and common terns Sterna hirundo to recolonize the islet. Rats were first detected on Feno in 2003, when tern breeding-numbers had decreased dramatically. During 2005 no terns bred on the islet and in 2006 fewer than five common tern pairs attempted to nest. Rat eradication was initiated in September 2006. The last rats were captured in March 2007. Monitoring conducted in September 2007, and May and September 2008 indicated that rats had not recolonized. Common terns quickly resumed breeding on Feno islet but numbers (c.120 pairs in 2009) are still below peak levels (c.240-280 pairs) recorded before rat infestation. Roseate terns on the other hand were slower to return but recovered faster with around 260 pairs in 2009, representing 22% of the Azores population. The success of the black rat eradication shows that surveillance and timely action are fundamental to conserve tern colonies vulnerable to rat predation in the Azores.

The red-fronted parakeet Cyanoramphus novaezelandiae is a vulnerable New Zealand endemic with a fragmented distribution, mostly inhabiting offshore islands free of introduced mammalian predators. Four populations have been established since the 1970s using captive-bred or wild-sourced individuals translocated to islands undergoing ecological restoration. To establish a new population in the Hauraki Gulf, North Island, a total of 31 parakeets were transferred from Little Barrier Island (Hauturu) to Motuihe Island in May 2008 and a further 18 in March 2009. Overall 55% and 42% of individuals from the first translocation were confirmed alive at 30 and 60 days post-release, respectively. Evidence of nesting and unassisted dispersal to a neighbouring island was observed within a year of release. These are outcomes are promising and indicate that translocation from a remnant wild population to an island free of introduced predators is a useful conservation tool to expand the geographic range of red-fronted parakeets.

 

In the Aravali hills of Rajahstan (northwest India), community-based approaches were followed to conserve Commiphora wightii, an endangered medicinal plant. Efforts were made to increase the effectiveness of wildlife conservation projects in the rural and tribal area of Aravali by promoting community participation through a C.wightii propagation and planting scheme, and education programs. Local communities participated and responded very positively to the initiatives. Approximately3,500, 3-month old Commiphora plantlets (each about 30 cm tall) propagated via cuttings, were planted out into their natural habitat.

 

Animal rescue centres release large numbers of captive-bred, rehabilitated or translocated animals into the wild annually but little is known about their post-release survival and behaviour. We developed a novel and innovative coupling of traditional radio-tags with new GPS loggers to track hand-reared Irish hare Lepus timidus hibernicus leverets after release into the wild. Cyanoacrylate SuperGlue® proved a poor fixative with two out of three leverets managing to detach their tags within 24 hours. Nevertheless, a total of 2,505 GPS locations were recorded every 60 seconds for one leveret over three nights (approx. 835 per night). The leveret dispersed <410 m from the original release site. It demonstrated exploratory behaviour including an ability to navigate accurately in a complex and unfamiliar environment returning to a habitual lie-up site each day. Its survival was confirmed up to 9 days post-release at which time its radio-tag detached, however, similarly aged leverets were sighted in the area for up to 2 months post-release (suggesting possible longer term survival). This is the first study to publish data from any GPS tagged lagomorph and provides 'proof-of-concept' that large quantities of behavioural data can be recovered from small mammals 1-2 kg. Further development of these techniques will be highly valuable to future studies.

 

On Coquet Island (5.4 ha), northeast England, a rapid increase in numbers of nesting herring Larus argentatus and lesser black-backed gulls L. fuscus raised concerns that the internationally important tern breeding colony would be displaced. The combined effect of several non-lethal control methods and systematic egg removal on these large gull species from 2000-2009, have been reductions in the number of gull pairs attempting to nest (from a peak of around 250 pairs to less than 20), the area occupied for nesting and nest density. The presence of the tern colony has been maintained, with increases in the population (5-year average) of roseate Sterna dougallii, arctic S. paradisaea and common terns S. hirundo.

The Scottish Wildlife Trust established a mobile flock of sheep to manage its Sites of Special Scientific Interest (SSSI) designated grasslands in eastern Scotland. A programme of monitoring (quadrat sampling and 'Site Condition Monitoring') was established to record vegetation responses to sheep grazing over several years. The project has resulted in the sheep-grazed grasslands moving towards favourable condition in terms of target plant communities. It has highlighted the need to take a flexible and responsive approach to conservation grazing, and has demonstrated the usefulness and necessity of detailed monitoring in guiding changes to grazing regimes; the level of grazing 'fine-tuning' could not have been achieved, in this instance, using external graziers.

Introduced common mynas Acridotheres tristis have been implicated as a threat to native biodiversity on the oceanic islands of St Helena and Ascension (UK). A rice-based bait treated with Starlicide® was broadcast for consumption by flocks of common mynas at the government rubbish tips on the two islands during investigations of potential myna management techniques. Bait was laid on St Helena during two 3-day periods in July and August 2009, and on Ascension over one 3-day period in November 2009. As a consequence of bait ingestion, dead mynas were found, especially under night roosts and also at the main drinking area on Ascension, following baiting. On St Helena early morning counts at the tip suggested that whilst the number of mynas fell after each treatment, lower numbers were not sustained; no reduction in numbers flying to the main roost used by birds using the tip as a feeding area was detected post-treatment. On Ascension, the number of mynas that fed at the tip and using a drinking site, and the numbers counted flying into night roosts from the direction of the tip, both indicated declines of about 70% (from about 360 to 109 individuals). Most dead birds were found following the first day of bait application, with few apparently dying after baiting on days 2 and 3. Despite the low concentration of Starlicide used, aversion to the bait was apparent during the trials. These results indicate that Starlicide may contribute to myna control programmes but questions remain over the mode of action of the chemical (in terms of individual differences among birds the responses to its toxic properties) and the longer-term susceptibility of birds to baiting.

Aerial application of cereal bait containing the poison brodifacoum was used to eradicate house mice Mus musculus from three islands in the Abel Tasman National Park, New Zealand, during July and August 2007. Poison bait was spread onto the islands by a helicopter using an under slung bait-spreading bucket and applied at a rate of 4 kg per hectare with a 50 % overlap in swath width. This gave an effective application rate of 8 kg per hectare. Bait was applied to the islands in two separate applications, 31 days apart. Monitoring for mice was carried out on all three islands for two years following the eradication attempt to determine the outcome. No mice or any sign of mice was detected. Eradicating mice from Tonga Island, Adele Island and Fisherman Island was the final step towards making the three islands free of introduced mammalian predators.

A translocation of South Island saddlebacks Philesturnus carunculatus from Ulva Island to Orokonui Ecosanctuary near Dunedin, New Zealand was conducted by a community group and university scientists in April 2009. In this paper we describe and assess methods used during this complicated five day translocation, which involved birds being held over-night in transfer boxes. Post-release surveys determined a minimum of 79% of individuals survived the critical initial 48 h after release. The survival rate did not appear to be affected by the presence or absence of perches in each transfer box, although the lack of perches does not follow best-practice for most passerine translocations. Experienced advisors should be involved during every phase of the translocation process.

 

Attempted eradication of house sparrows Passer domesticus from Round Island (Mauritius), Indian Ocean
Bednarczuk E., Feare C.J., Lovibond S., Tatayah V. & Jones C.G. (2010), 7, 75-86

In 1982, house sparrows Passer domesticus were confirmed as having established a naturalized population on Round Island (Mauritius). A planned pending translocation of an endangered Mauritian endemic bird, Mauritius fody Foudia rubra to Round Island suggested eradication of sparrows to be pertinent as they were potentially a resource competitor and vector of parasites and pathogens. An attempted eradication using a combination of techniques was undertaken from 19 August 2008 to 25 February 2009. Following food preference trials, microwave-sterilized millet seed was used as bait for trapping and for narcotisation with alphachloralose. House sparrows were also shot, caught in mist nets and on glue sticks, and some nests and chicks were removed. In total, 320 house sparrows were killed, with trapping accounting for 87% (277) of birds removed. However, the population was not eradicated. The assumption that the Round Island house sparrow population was derived from one storm-driven event and is closed to further immigrants needs to be investigated in order to determine whether long-term eradication is in fact feasible. Suggestions for improving the prospects for eradication or ongoing management of the population are presented.

The critically endangered Christmas orchid Masdevallia tovarensis is endemic to cloud forest within the state of Aragua (Colonia Tovar) northern Venezuela. Its propagation has been little studied, particularly regarding in vitro cultivation techniques. In an attempt to asymbiotically and sexually micropropagate this autochthonous species, seeds were used from indehiscent capsules obtained from nurseries in the vicinity of areas where this orchid naturally occurs. The effect of Murashige and Skoog nutrition medium, and different concentrations of thidiazuron, benzyladenine (BA) and naphthaleneacetic acid (NAA) on seed germination were evaluated. In vitro asymbiotic germination was characterized by initial swelling of seeds, increase of embryo size and formation of protocorm-like bodies (PLBs), similar to those naturally generated during symbiotic germination. After three months, the PLBs started to sprout leaves and roots to form seedlings. In all treatments, the formation of PLBs was observed, although in higher number when using the combination BA (2.0 mg/l) + NAA (1.5 mg/l). A protocol was obtained that will enable mass propagation by means of asymbiotic germination of seeds in vitro.

To assist in the conservation of Commiphora wightii (an endangered medicinal tree),experiments were undertaken to develop an efficient, rapid and inexpensive method for large scale propagation. Two methods were trialed, propagation by stem cuttings and in vitro tissue culture. Propagation by the stem cutting method was found to be both more successful and produced plants of a suitable size for transplanting more rapidly than in vitro cultivation.Stem cutting propagation was also inexpensive and easier to perform, as compared to in vitro propagation. The cost to produce a plant of suitable size for transplanting was 3 Indian Rupees (INR) using the stem cutting method and 80 INR by the in vitro method.

Commiphora wightii is an endangered tree of arid and semi-arid tracts of northern Africa to northwest India. It is an important medicinal plant well-known for its oleo-gum-resin with cholesterol reducing properties. However, it has been over-exploited such that it is on the verge of extinction in the Indian part of its range. The present study reports the use of tissue culture as a viable alternative to propagation via stem cuttings as well as seedlings for conservation of this valuable plant. The work presented describes the development of two tissue culture based pathways for plant production, their acclimatization and successful field transfer. Plants derived from in vitro propagation have been growing well under field conditions for over three years (April 2007 to August 2010). Flowering and fruiting has taken place, as would be expected in similarly sized wild plants, and plants have exhibited a good rate of growth.

The initiative has proven cost-effective in terms of producing plants from culture initiation stage to a hardened plant of size suitable for transplanting into the field; the cost of a single plant produced through a somatic embryogenesis pathway was about Indian Rupees (INR) 19 (equivalent to Pound Sterling (GBP) 0.26), while that produced through a cotyledonary node based protocol was INR 27 (GBP 0.37). The study clearly indicates the applicability and benefits of using tissue culture technology to assist in conservation of C. wightii.

Although widespread in South America, the yellow-headed sideneck turtle Podocnemis unifilis is considered 'Vulnerable' in Venezuela. A large portion of eggs of this riverine species may be lost due to predation (including collection by humans) and flooding. As a technique to enhance reproductive success, transfer of wild-laid clutches of eggs to protected zones for incubation has been successfully carried out. This study undertaken in 2009, evaluated the hatch success of clutches transferred to artificial nest chambers at protected locations compared with natural clutches left in situ along stretches of the Cojedes and Manapire rivers (Venezuela). Along the Cojedes River, 78 turtle nests were located, 27 of which were excavated and eggs transferred for incubation. In the Manapire River, 87 nests were located, eggs from 13 of which were transferred for incubation. In the Cojedes River, 28.2% of study clutches (n=22) were lost due to predation and flooding; in the Manapire River, 85% of nests (n=74) were lost due to predation (humans and other animals). At Cojedes River, hatching success of eggs in artificial nests was 88.2% and 63.2% in natural nests. At Manapire River, hatching success of eggs in artificial nests was 42% and 0% in natural nests.

The mottled grasshopper Myrmeleotettix maculatus is locally rare in Essex, southeast England. To increase the number of populations of this grasshopper in the county, 40 adults (20 female, 20 male) were captured using sweep netting at Colne Point (an Essex Wildlife Trust coastal nature reserve) and transferred to Environment Agency sand dune flood defences at the nearby town of Jaywick in July and August 2009. At least in the short-term, the translocation has been successful; in June and August 2010 at the release site a small number of adult female and male mottled grasshoppers were located indicating that successful breeding had occurred. It is hoped that a new population at Jaywick will establish and spread in the longer-term in adjacent sandy areas recently planted with marram grass Ammophila arenaria.

During 2009, wild eggs of two Venezuelan crocodilians (Orinoco crocodile Crocodylus intermedius and American crocodile C. acutus) were collected and artificially incubated using low-technology methods under basic conditions. Hatch success was 53.7% for C. intermedius eggs, and 65.6% for C. acutus eggs. Overall, 316 hatchlings were obtained from a total of 521 eggs (60.7% hatch success). These results compare favourably with similar artificial incubation trials, but incubation time for C. acutus eggs (87 to 102 days) was rather longer than the typical incubation period for the species (around 82 to 83 days). This may be indicative of a low incubation temperature; if so, most of the hatchlings may have been females. Only as these young mature will their sex be determinable. Hatchlings were taken to captive-rearing facilities where they will be maintained until they reach a suitable size for release into the wild. Participation of local people in this project was considered a very important factor in its success, and had additional conservation benefits including raising public awareness of the plight of crocodile populations and problems of over-exploitation in the study areas.

In 1998, procumbent pearlwort Sagina procumbens a non-native and invasive plant was discovered on Gough Island (Tristan da Cunha). Efforts to eradicate this species have been underway since 2000. To date it has been restricted to a small (400 m length; approximately 1.2-1.6 ha area) but complex stretch of coastal cliffs. Measures of seed density, based on germination trials of soil samples collected from Sagina infested areas, indicate that 'standard eradication' methods (digging up individual plants, heat-treating soil and spot-treatment with herbicides) in place over the last 10 years have resulted in a three orders of magnitude reduction in the seed load. However, around 200 seedlings per m² continue to be recorded due to germination from seeds within the soil. In 2008-09 we investigated the effectiveness of three methods designed to eradicate Sagina on Gough: 'standard eradication' based on methods used in previous years (n = 5 plots); monthly 'herbicide treatment' across the whole plot (n = 4 plots); and 'soil stripping' where all plants and soil was removed down to bedrock (n = 2 plots). Sagina plants remained present within the standard eradication plots, with an average of 64 ± 79 (range 6 - 200) plants recorded per plot cleared in 8-months of monitoring. No Sagina plants were found in herbicide treated plots, although this method is unlikely to tackle the problem of dormant seeds remaining within the soil. Soil stripping was effective at removing the seed bank and only five and 33 plants were found over the 8-months monitoring period. We recommend that a combination of monthly herbicide spraying across the whole infested area (to prevent plants maturing and setting seed) and a programme of soil stripping (working from the outer edge of the plants range) to remove the seed bank, be utilised in order to provide a potential method to eradicate Sagi from Gough.

Trials were undertaken to assess the effectiveness of various treatments aimed at reinstating heathland vegetation at Hobbister RSPB Reserve (Orkney Islands) on a denuded area where no vascular plant growth had occurred since peat had been extracted commercially over 30 years previously. A management history of Hobbister was collated and information (derived from a literature search of restoration techniques) combined with observations of physical conditions at the site, was used to develop a list of possible impediments to heathland vegetation regeneration. Based upon these findings, eight sets of treatments were designed and applied to trial plots devoid of vegetation in June 2006. Plots were surveyed in August 2009. A combination of peat dust, heath mulch and geojute gave best results with 80% cover of vascular plants (including 70% by heather Calluna vulgaris). Although two grass-seed addition plots had higher cover values (91 and 86%) these were dominated by one of the sown species (red fescue Festuca rubra). Peat dust plus heath mulch addition also produced good cover (40%) of Calluna. Adding fertiliser did not assist in target heathland plant species re-colonisation. On the untreated control plot, vascular plant cover remained at zero.

 

The invasive New Zealand pygmyweed Crassula helmsii was eradicated from approximately 120 ha of coastal grazing marsh at a site in southeast England by shallow flooding of the area with sea water for 12 months. This method of eradication can only be used where saline water can be held on a site (with due regard for potential impacts on non-target species). We have not come across an example of successful C. helmsii eradication on this scale by using other methods.