Improving supplementary feeding in species conservation

Supplementary feeding is often a knee-jerk reaction to population declines, and its application is not critically evaluated, leading to polarized views among managers on its usefulness. Here, we advocate a more strategic approach to supplementary feeding so that the choice to use it is clearly justified over, or in combination with, other management actions and the predicted consequences are then critically assessed following implementation. We propose combining methods from a set of specialist disciplines that will allow critical evaluation of the need, benefit, and risks of food supplementation. Through the use of nutritional ecology, population ecology, and structured decision making, conservation managers can make better choices about what and how to feed by estimating consequences on population recovery across a range of possible actions. This structured approach also informs targeted monitoring and more clearly allows supplementary feeding to be integrated in recovery plans and reduces the risk of inefficient decisions. In New Zealand, managers of the endangered Hihi (Notiomystis cincta) often rely on supplementary feeding to support reintroduced populations. On Kapiti island the reintroduced Hihi population has responded well to food supplementation, but the logistics of providing an increasing demand recently outstretched management capacity. To decide whether and how the feeding regime should be revised, managers used a structured decision making approach informed by population responses to alternative feeding regimes. The decision was made to reduce the spatial distribution of feeders and invest saved time in increasing volume of food delivered into a smaller core area. The approach used allowed a transparent and defendable management decision in regard to supplementary feeding, reflecting the multiple objectives of managers and their priorities

Moving I`iwi (Vestiaria coccinea) as a Surrogate for Future Translocations of Endangered `Akohekohe (Palmeria dolei)

Translocations often play an important role in the recovery of endangered species. To assess feasibility for translocation of endangered `Akohekohe (Palmeria dolei), we conducted an experimental translocation of I`iwi (Vestiaria coccinea) from east to west Maui. Mist-netting, veterinary screening of candidate birds, and helicopter transport of healthy I`iwi were successful, resulting in no injuries or mortalities. Translocated birds were assigned to two types of release. Hard release birds were radio tagged and released on the day of translocation. In contrast, soft release birds were held in large cages for 7 days and fed artificial nectar. During holding soft release I`iwi feeding rates, fecal production, and mass were monitored. Soft release birds suffered 33% mortality during the holding period. At the end of the holding period, soft release survivors were outfitted with a radio transmitter and released. All translocated I`iwi were followed by radio telemetry for an average of 21 days. Once released, soft release birds showed higher rates of movement, possibly reflecting conflict with established hard released I`iwi. Our results suggest that translocation efforts for wild `Akohekohe will be successful if hard release protocols are followed

Characterization of Mauritius parakeet (Psittacula eques) microsatellite loci and their cross-utility in other parrots (Psittacidae, Aves).

We characterized 21 polymorphic microsatellite loci in the endangered Mauritius parakeet (Psittacula eques). Loci were isolated from a Mauritius parakeet genomic library that had been enriched separately for eight different repeat motifs. Loci were characterized in up to 43 putatively unrelated Mauritius parakeets from a single population inhabiting the Black River Gorges National Park, Mauritius. Each locus displayed between three and nine alleles, with the observed heterozygosity ranging between 0.39 and 0.96. All loci were tested in 10 other parrot species. Despite testing few individuals, between seven and 21 loci were polymorphic in each of seven species tested

Is the detection of aquatic environmental DNA influenced by substrate type?

The use of environmental DNA (eDNA) to assess the presence-absence of rare, cryptic or invasive species is hindered by a poor understanding of the factors that can remove DNA from the system. In aquatic systems, eDNA can be transported out either horizontally in water flows or vertically by incorporation into the sediment. Equally, eDNA may be broken down by various biotic and abiotic processes if the target organism leaves the system. We use occupancy modelling and a replicated mesocosm experiment to examine how detection probability of eDNA changes once the target species is no longer present. We hypothesise that detection probability falls faster with a sediment which has a large number of DNA binding sites such as topsoil or clay, over lower DNA binding capacity substrates such as sand. Water removed from ponds containing the target species (the great crested newt) initially showed high detection probabilities, but these fell to between 40% and 60% over the first 10 days and to between 10% and 22% by day 15: eDNA remained detectable at very low levels until day 22. Very little difference in detection was observed between the control group (no substrate) and the sand substrate. A small reduction in detection probability was observed between the control and clay substrates, but this was not significant. However, a highly significant reduction in detection probability was observed with a topsoil substrate. This result is likely to have stemmed from increased levels of PCR inhibition, suggesting that incorporation of DNA into the sediment is of only limited importance. Surveys of aquatic species using eDNA clearly need to take account of substrate type as well as other environmental factors when collecting samples, analysing data and interpreting the result

Spatial differences in prey preference by tigers across the Bangladesh Sundarbans reveal a need for customised strategies to protect prey populations

The Sundarbans is the only mangrove habitat in the world to support tigers Panthera tigris, whose persistence there is believed to be dependent on a very limited number of prey species. Conservation managers therefore need to understand how tigers utilise available prey species on a spatial scale in order to formulate a prey-based protection strategy for this global-priority tiger landscape. A total of 512 scat samples were collected during a survey of 1984 km2 of forest across 4 sample blocks in the 6017 km2 of the Bangladesh Sundarbans. Analysis of scat composition and prey remains reliably identified 5 major prey species, of which spotted deer Axis axis and wild pig Sus scrofa contributed a cumulative biomass of 89% to tiger diet. Tiger preference for prey species was highly skewed towards spotted deer and wild pig, but the relative contribution of these 2 species differed significantly across the 4 study areas, which spanned the Sundarbans, demonstrating important spatial patterns of tiger prey preference across the Sundarbans landscape. Given the comparatively limited number of prey species available to support the dwindling tiger population, different strategies are needed in different parts of the Sundarbans to support tiger populations and to protect spotted deer and wild pig populations from unabated poaching

Comparison of two Citizen Scientist Methods for Collecting Pond Water Samples for Environmental DNA Studies

The use of environmental DNA (eDNA) for the survey of aquatic species offers a wide range of benefits over conventional surveys and has begun to be used by citizen scientists. One advantage of eDNA over conventional survey protocols is the comparative ease with which samples can be collected over a wide geographic area by citizen scientists. However, eDNA collection protocols vary widely between different studies, promoting a need to identify an optimum method. Collection protocols include ethanol precipitation and various filtration methods including those that use electronic vacuum or peristaltic pumps, hand pumps or syringes to capture eDNA on a membrane. We compare the effectiveness of two eDNA collection methods suitable for use by citizen scientists: glass-microfiber syringe filtration and ethanol precipitation. Paired samples of water were analysed for great crested newt (Triturus cristatus) DNA using (1) a laboratory tank experiment using different dilutions of water inoculated with newt DNA; and (2) by sampling naturally colonised ponds. Although syringe filters consistently yielded greater DNA extract concentrations in the tank experiments, this was not the case in samples collected from the field where no difference between the two methods was identified. Clearly, properties within the water – such as algae and particulate matter - can influence the amount of DNA captured by the two methods, so the sampling protocol of choice will depend on the design and goals of the study

Extinction risk and conservation options for Maui Parrotbill, an endangered Hawaiian honeycreeper

Extinction rates for island birds around the world have been historically high. For forest passerines, the Hawaiian archipelago has suffered some of the highest extinction rates and reintroduction is a conservation tool that can be used to prevent the extinction of some of the remaining endangered species. Population viability analyses can be used to assess risks to vulnerable populations and evaluate the relative benefits of conservation strategies. Here we present a population viability analysis to assess the long-term viability for Maui parrotbill(s) (Kiwikiu) Pseudonestor xanthophrys, a federally endangered passerine on the Hawaiian island of Maui. Contrary to indications from population monitoring, our results indicate Maui parrotbills may be unlikely to persist beyond 25 years. Our modeling suggests female mortality as a primary factor driving this decline. To evaluate and compare management options involving captive rearing and translocation strategies we made a female-only stage-structured, meta-population simulation model. Due to the low reproductive potential of Maui parrotbills in captivity, the number of individuals (~ 20% of the global population) needed to source a reintroduction solely from captive reared birds is unrealistic. A reintroduction strategy that incorporates a minimal contribution from captivity and instead translocates mostly wild individuals was found to be the most feasible management option. Habitat is being restored on leeward east Maui, which may provide more favorable climate and habitat conditions and promote increased reproductive output. Our model provides managers with benchmarks for fecundity and survival needed to ensure reintroduction success, and highlights the importance of establishing a new population in potentially favorable habitat to ensure long-term persistence

What's in a name? Common name misuse potentially confounds the conservation of the wild camel Camelus ferus

Common names allow species diversity to be acknowledged by experts and non-specialists alike; they are descriptors with both scientific and cultural implications. However, a lack of clarity when using a common name could risk altering perceptions of threatened species. This is the case for the Critically Endangered wild camel Camelus ferus, which, despite extensive evidence of its species status, is frequently referred to in English as wild Bactrian camel. However, the wild camel (Mongolian: хавтгай, khavtgai; Chinese: 野骆驼, ye luo tuo) is not a wild version of the domestic Bactrian camel Camelus bactrianus but a separate species near extinction, with an estimated population of c. 950. Failure to clearly separate Bactrian and wild camels in name risks masking the plight of the few remaining wild camels with the visible abundance of the domesticated species. Here we advocate the use of the accurate English common name wild camel for C. ferus ideally alongside its Indigenous names to correctly represent its cultural and conservation importance

Endemic, endangered, and evolutionarily significant: Cryptic lineages in Seychelles’ frogs

Cryptic diversity that corresponds with island origin has been previously reported in the endemic, geographically restricted sooglossid frogs of the Seychelles archipelago. The evolutionary pattern has not been fully explored, and given current amphibian declines and the increased extinction risk faced by island species, we sought to identify evolutionarily significant units (ESUs) to address conservation concerns for these highly threatened anurans. We obtained genetic data for two mitochondrial (mtDNA) and four nuclear (nuDNA) genes from all known populations of sooglossid frog (the islands of Mahé, Praslin, and Silhouette) to perform phylogenetic analyses and construct nuDNA haplotype networks. Bayesian and maximum likelihood analyses of mtDNA support monophyly and molecular differentiation of populations in all species that occur on multiple islands. Haplotype networks using statistical parsimony revealed multiple high-frequency haplotypes shared between islands and taxa, in addition to numerous geographically distinct (island-specific) haplotypes for each species. We consider each island-specific population of sooglossid frog as an ESU and advise conservation managers to do likewise. Furthermore, our results identify each island lineage as a candidate species, evidence for which is supported by Bayesian Poisson Tree Processes analyses of mtDNA, and independent analyses of mtDNA and nuDNA using the multispecies coalescent. Our findings add to the growing understanding of the biogeography and hidden diversity within this globally important region

Phylogeography of Panthera tigris in the mangrove forest of the Sundarbans

Tigers Panthera tigris in the Sundarbans represent the only population adapted to living in mangrove forest habitat. Several studies, based on limited morphological and genetic data, have described the population as being differentiated from the Bengal tiger subspecies P. tigris tigris. The phylogenetic ancestry of the Sundarbans population has also remained poorly understood. We generated 1263 bp of mtDNA sequences across 4 mtDNA genes for 33 tiger samples from the Bangladesh Sundarbans and compared these with 33 mtDNA haplotypes known from all subspecies of extant tigers. We detected 3 haplotypes within the Sundarbans tigers, of which one is unique to this population and the remaining 2 are shared with tiger populations inhabiting central Indian landscapes. Phylogenetic analyses using maximum likelihood and Bayesian inferences supported the Sundarbans tigers as being paraphyletic, indicating a close phylogenetic relationship with other populations of Bengal tigers, from which the Sundarbans population diverged around 26000 yr ago. Our phylogenetic analyses, together with evidence of ecological adaptation to the unique mangrove habitat, indicate that the Sundarbans population should be recognised as a separate management unit. We recommend that conservation management must focus on sustaining this representative tiger population adapted to mangrove habitat while at the same time recognising that trans-boundary conservation efforts through reintroduction or exchange of individuals, to enhance genetic diversity, might be needed in the future as a last resort for population recovery