Bringing the Tiger Back from the Brink—The Six Percent Solution

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Assessing anti-rabies baiting – what happens on the ground?

BACKGROUND: Rabies is one of the most hazardous zoonoses in the world. Oral mass vaccination has developed into the most effective management method to control fox rabies. The future need to control the disease in large countries (i.e. Eastern Europe and the Americas) forces cost-benefit discussions. The 'Increase bait density' option refers to the usual management assumption that more baits per km(2 )could compensate for high fox abundance and override the imperfect supply of bait pieces to the individual fox. METHODS: We use a spatial simulation, which combines explicitly fox space use (tessellation polygons) and aeroplane flight lines (straight lines). The number of baits actually falling into each polygon is measured. The manager's strategic options are converted into changes of the resulting bait distribution on the ground. The comparison enables the rating of the options with respect to the management aim (i.e. accessibility of baits). RESULTS: Above 5% (approx. 10%) of all fox groups without any bait (at most 5 baits) relate to the baiting strategy applied in the field (1 km spaced parallel flight lines, 20 baits per km(2 )distributed) under habitat conditions comparable to middle and western Europe (fox group home-range 1 km(2), 2.5 adults; reference strategy). Increasing the bait density on the same flight-line pattern neither reduces the number of under-baited fox group home-ranges, nor improves the management outcome and hence wastes resources. However, reducing the flight line distance provides a more even bait distribution and thus compensates for missed fox groups or extra high fox density. The reference strategy's bait density can be reduced when accounting for the missed fox groups. The management result with the proper strategy is likely the same but with reduced costs. CONCLUSION: There is no overall optimal strategy for the bait distribution in large areas. For major parts of the landscape, the reference strategy will be more competitive. In situations where set backs are attributed to non-homogeneous bait accessibility the distribution scheme has to be refined zone-based (i.e. increase of the flight line length per unit area). However, increase in bait density above the reference strategy appears inappropriate at least for non-urban abundance conditions of the red fox

Global large carnivore conservation and international law

International cooperation, including through international legal instruments, appears important for the conservation of large carnivores worldwide. This is due to, inter alia, the worrying conservation status and population trends of many large carnivore species; the importance of large carnivores for biodiversity conservation at large; their occurrence at low densities, with many populations extending across various countries; and the international nature of particular threats. For the 31 heaviest species in the order Carnivora, this study (i) documents to what extent existing international legal instruments contribute to large carnivore conservation, and (ii) identifies ways of optimizing their contribution in this regard. From this dual perspective, it reviews all global wildlife conservation treaties—Ramsar Wetlands Convention, World Heritage Convention, Convention on Trade in Endangered Species, Convention on Migratory Species (CMS), Convention on Biological Diversity (CBD)—and selected regional instruments, using standard international law research methodology. Results indicate that a substantial body of relevant international law already exists, whereas simultaneously there is clear potential for enhancing the contribution of international law to large carnivore conservation. Avenues for pursuing this include promotion of instruments’ effective implementation; clarification of their precise implications for large carnivore conservation; development of formal guidance; expansion of instruments’ scope in terms of species, sites and countries; and creation of new instruments. The CMS and CBD hold particular potential in some of these respects. The experiences being gained under European legal instruments constitute an interesting ‘laboratory’ regarding human coexistence with expanding large carnivore populations and transboundary cooperation at the (sub)population level

Kinetics of maternal immunity against rabies in fox cubs (Vulpes vulpes)

BACKGROUND: In previous experiments, it was demonstrated that maternal antibodies (maAb) against rabies in foxes (Vulpes vulpes) were transferred from the vixen to her offspring. However, data was lacking from cubs during the first three weeks post partum. Therefore, this complementary study was initiated. METHODS: Blood samples (n = 281) were collected from 64 cubs (3 to 43 days old) whelped by 19 rabies-immune captive-bred vixens. Sera was collected up to six times from each cub. The samples were analysed by a fluorescence focus inhibition technique (RFFIT), and antibody titres (nAb) were expressed in IU/ml. The obtained data was pooled with previous data sets. Subsequently, a total of 499 serum samples from 249 cubs whelped by 54 rabies-immune vixens were fitted to a non-linear regression model. RESULTS: The disappearance rate of maAb was independent of the vixens' nAb-titre. The maAb-titre of the cubs decreased exponentially with age and the half-life of the maAb was estimated to be 9.34 days. However, maAb of offspring whelped by vixens with high nAb-titres can be detected for longer by RFFIT than that of offspring whelped by vixens with relatively low nAb-titres. At a mean critical age of about 23 days post partum, maAb could no longer be distinguished from unspecific reactions in RFFIT depending on the amount of maAb transferred by the mother. CONCLUSIONS: The amount of maAb cubs receive is directly proportional to the titre of the vixen and decreases exponentially with age below detectable levels in seroneutralisation tests at a relatively early age

Assessing personality in San Joaquin kit fox in situ: efficacy of field-based experimental methods and implications for conservation management

Utilisation of animal personality has potential benefit for conservation management. Due to logistics of robust behavioural evaluation in situ, the majority of studies on wild animals involve taking animals into captivity for testing, potentially compromising results. Three in situ tests for evaluation of boldness in San Joaquin kit fox (Vulpes macrotis mutica) were developed (ENOT: extended novel object test; RNOT: rapid novel object test; TH: trap/handling test). Each test successfully identified variation in boldness within its target age class(es). The TH test was suitable for use across all age classes. Tests were assessed for in situ suitability and for quantity/quality of data yielded. ENOT was rated as requiring high levels of time, cost and labour with greater likelihood of failure. However, it was rated highly for data quantity/quality. The TH test was rated as requiring little time, labour and cost, but yielding lower quality data. RNOT was rated in the middle. Each test had merit and could be adapted to suit project or species constraints. We recommend field-based evaluation of personality, reducing removal of animals from the wild and facilitating routine incorporation of personality assessment into conservation projects

Emergency vaccination of rabies under limited resources – combating or containing?

BACKGROUND: Rabies is the most important viral zoonosis from a global perspective. Worldwide efforts to combat the disease by oral vaccination of reservoirs have managed to eradicate wildlife rabies in large areas of central Europe and North-America. Thus, repeated vaccination has been discontinued recently on a geographical scale. However, as rabies has not yet been eradicated globally, a serious risk of re-introduction remains. What is the best spatial design for an emergency vaccination program – particularly if resources are limited? Either, we treat a circular area around the detected case and run the risk of infected hosts leaving the limited control area, because a sufficient immunisation level has not yet been built up. Or, initially concentrate the SAME resources in order to establish a protective ring which is more distant from the infected local area, and which then holds out against the challenge of the approaching epidemic. METHODS: We developed a simulation model to contrast the two strategies for emergency vaccination. The spatial-explicit model is based on fox group home-ranges, which facilitates the simulation of rabies spread to larger areas relevant to management. We used individual-based fox groups to follow up the effects of vaccination in a detailed manner. Thus, regionally – bait distribution orientates itself to standard schemes of oral immunisation programs and locally – baits are assigned to individual foxes. RESULTS: Surprisingly, putting the controlled area ring-like around the outbreak does not outperform the circular area of the same size centred on the outbreak. Only during the very first baitings, does the ring area result in fewer breakouts. But then as rabies is eliminated within the circle area, the respective ring area fails, due to the non-controlled inner part. We attempt to take advantage of the initially fewer breakouts beyond the ring when applying a mixed strategy. Therefore, after a certain number of baitings, the area under control was increased for both strategies towards the same larger circular area. The circle-circle strategy still outperforms the ring-circle strategy and analysis of the spatial-temporal disease spread reveals why: improving control efficacy by means of a mixed strategy is impossible in the field, due to the build-up time of population immunity. CONCLUSION: For practical emergency management of a new outbreak of rabies, the ring-like application of oral vaccination is not a favourable strategy at all. Even if initial resources are substantially low and there is a serious risk of rabies cases outside the limited control area, our results suggest circular application instead of ring vaccination

Carnivore Translocations and Conservation: Insights from Population Models and Field Data for Fishers (Martes pennanti)

Translocations are frequently used to restore extirpated carnivore populations. Understanding the factors that influence translocation success is important because carnivore translocations can be time consuming, expensive, and controversial. Using population viability software, we modeled reintroductions of the fisher, a candidate for endangered or threatened status in the Pacific states of the US. Our model predicts that the most important factor influencing successful re-establishment of a fisher population is the number of adult females reintroduced (provided some males are also released). Data from 38 translocations of fishers in North America, including 30 reintroductions, 5 augmentations and 3 introductions, show that the number of females released was, indeed, a good predictor of success but that the number of males released, geographic region and proximity of the source population to the release site were also important predictors. The contradiction between model and data regarding males may relate to the assumption in the model that all males are equally good breeders. We hypothesize that many males may need to be released to insure a sufficient number of good breeders are included, probably large males. Seventy-seven percent of reintroductions with known outcomes (success or failure) succeeded; all 5 augmentations succeeded; but none of the 3 introductions succeeded. Reintroductions were instrumental in reestablishing fisher populations within their historical range and expanding the range from its most-contracted state (43% of the historical range) to its current state (68% of the historical range). To increase the likelihood of translocation success, we recommend that managers: 1) release as many fishers as possible, 2) release more females than males (55–60% females) when possible, 3) release as many adults as possible, especially large males, 4) release fishers from a nearby source population, 5) conduct a formal feasibility assessment, and 6) develop a comprehensive implementation plan that includes an active monitoring program

Multispectral analysis of Northern Hemisphere temperature records over the last five millennia

Aiming to describe spatio-temporal climate variability on decadal-to-centennial time scales and longer, we analyzed a data set of 26 proxy records extending back 1,000–5,000 years; all records chosen were calibrated to yield temperatures. The seven irregularly sampled series in the data set were interpolated to a regular grid by optimized methods and then two advanced spectral methods—namely singular-spectrum analysis (SSA) and the continuous wavelet transform—were applied to individual series to separate significant oscillations from the high noise background. This univariate analysis identified several common periods across many of the 26 proxy records: a millennial trend, as well as oscillations of about 100 and 200 years, and a broad peak in the 40–70-year band. To study common NH oscillations, we then applied Multichannel SSA. Temperature variations on time scales longer than 600 years appear in our analysis as a dominant trend component, which shows climate features consistent with the Medieval Warm Period and the Little Ice Age. Statistically significant NH-wide peaks appear at 330, 250 and 110 years, as well as in a broad 50–80-year band. Strong variability centers in several bands are located around the North Atlantic basin and are in phase opposition between Greenland and Western Europe