Biology subjects

Petrovan, S. O.

Publications and source records attributed to Petrovan, S. O..

8 recordsLinked to original sources

bioRxiv2024

What works to improve species conservation state? An analysis of species whose state has improved and the actions responsible

Understanding the consequences of past conservation efforts is essential to inform the means of maintaining and restoring species. Data from the IUCN Red List for 67,217 comprehensively assessed animal species were reviewed and analysed to determine (i) which conservation actions have been implemented for different species, (ii) which types of species have improved in state and (iii) which actions are likely to have driven the improvements. At least 51.8% (34,847) of assessed species have actions reported, mostly comprising protected areas (82.7%), with more actions reported for both terrestrial tetrapods and warm-water reef-building corals and fewer for fish, dragonflies and damselflies and crustaceans. Species at greater risk of extinction have a wider range of species-targeted actions reported compared to less threatened species, reflecting differences in documentation and conservation efforts. Six times more species have deteriorated rather than improved in their Red List category. Almost all species that improved have conservation actions in place; species that improved in state typically were historically at high risk of extinction, have smaller ranges and lacked a range of reported threats, particularly hunting and habitat loss or degradation. All types of conservation action were associated with improvements in state, especially reintroductions and invasive species control, alongside, for amphibians and birds, area management. This suggests a range of conservation interventions have successfully conserved some species at greatest risk but have rarely recovered populations to resilient levels. Scaling up the extent and intensity of conservation interventions, particularly landscape-scale actions that benefit broadly distributed species, is urgently needed to assist the recovery of biodiversity.

zoology↗

bioRxiv2024

Novel mark recapture surveys reveal stable pigmentation patterns but age-related melanism in the common frog Rana temporaria

Variations in melanin-based pigmentation patterns are frequent evolutionary adaptations in vertebrates and allow the study of phenotypic diversity across populations as well as individual recognition. Age-related changes in such pigmentation patterns have been demonstrated for several species but remain rarely explored in adult amphibians. For the wide-ranging European common frog (Rana temporaria) dorsal melanism was discussed in the context of UV protection at high altitude or as thermal adaptation at high latitude, yet patterns remain unquantified across most of its range or in terms of individual variation over time. We investigated dorsal pigmentation patterns in a wild population of R. temporaria in a lowland site in England which was the focus of a 7 year high-intensity mark recapture programme. We collected dorsal photographs using phone cameras and analysed pigmentation patterns using visual classifications and ImageJ image processing software. Pigmentation was highly variable between individuals but overall: (i) the number of melanin-based spots was largely stable or decreased over time as enlarging spots sometimes merged but never disappeared; (ii) the total melanin-based pigmented area increased significantly over time on average, albeit not for all individuals; and (iii) pigmentation was similar in males compared to females although the darkest individuals tended to be males. Our analysis reveals important patterns in pigmentation change and stability in this widespread species but the mechanisms and specific drivers remain unknown.

zoology↗

bioRxiv2023

Assessing the global prevalence of wild birds in trade

Trade represents a significant threat to many wild species and is often clandestine and poorly monitored. Information on which species are most prevalent in trade, and potentially threatened by it, therefore remains fragmentary. We mobilised seven global datasets on birds in trade to identify the species or groups of species that might be at particular risk. These datasets sample different parts of the broad trade spectrum but we nevertheless find a statistically strong congruence between them in which species are recorded in trade. Furthermore, the frequency with which species are recorded within datasets is positively correlated with their occurrence across datasets. This allows us to propose a trade prevalence score that can be applied to all bird species globally. This score discriminates well between species known from semi-independent assessments to be heavily or unsustainably traded and all other species. Globally, 45.1% of all bird species, and 36.7% of globally threatened bird species, were recorded in at least one of the seven datasets. Species listed in Appendices I or II of CITES, species with large geographical distributions and non-songbirds had higher trade prevalence scores. Speciose orders with high mean trade prevalence scores include the Falconiformes, Psittaciformes, Accipitriformes, Anseriformes, Bucerotiformes and Strigiformes. Despite their low mean prevalence score, Passeriformes accounted for the highest overall number of traded species of any order but had low representation in CITES Appendices. Geographical hotspots where large numbers of traded species co-occur differed between songbirds (South-East Asia and Eurasia) and non-songbirds (central South America, sub-Saharan Africa and India). This first attempt to quantify and map the relative prevalence in trade of all bird species globally can be used to identify species and groups of species which may be at particular risk of harm from trade and can inform conservation and policy interventions to reduce its adverse impacts. Article impact statementThe first metric to estimate the prevalence in trade of all the worlds bird species is presented.

ecology↗

bioRxiv2021

Reducing publication delay to improve the efficiency and impact of conservation science

Evidence-based decision making is most effective with comprehensive access to scientific studies. If studies face delays or barriers to being published, the useful information they contain may not reach decision-makers in a timely manner. This represents a potential problem for mission-oriented disciplines where access to the latest data is paramount to ensure effective actions are deployed. We sought to analyse the severity of publication delay in conservation science -- a field that requires urgent action to prevent the loss of biodiversity. We used the Conservation Evidence database to assess the length of publication delay (time from finishing data collection to publication) in the literature that tests the effectiveness of conservation interventions. From 7,415 peer-reviewed and non-peer-reviewed studies of conservation interventions published over eleven decades, we find that the mean publication delay (time from completing data collection to publication) was 3.6 years and varied by conservation subject -- a smaller delay was observed for studies focussed on the management of captive animals. Publication delay was significantly smaller for studies in the non-journal literature (typically non-peer-reviewed) compared to studies published in scientific journals. Although we found publication delay has marginally increased over time (1912-2020), this change was weak post-1980s. Publication delay also varied inconsistently between studies on species with different IUCN Red List statuses and there was little evidence that studies on more threatened species were subject to a smaller delay. We discuss the possible drivers of publication delay and present suggestions for scientists, funders, publishers, and practitioners to reduce the time taken to publish studies. Although our recommendations are aimed at conservation science, they are highly relevant to other mission-driven disciplines where the rapid dissemination of scientific findings is important.

scientific communication and education↗

bioRxiv2020

Poor availability of context-specific evidence hampers decision-making in conservation

Evidence-based conservation relies on robust and relevant evidence. Practitioners often prefer locally relevant studies whose results are more likely to be transferable to the context of planned conservation interventions. To quantify the availability of relevant evidence for amphibian and bird conservation we reviewed Conservation Evidence, a database of quantitative tests of conservation interventions. Studies were geographically clustered and found at extremely low densities - fewer than one study was present within a 2,000 km radius of a given location. The availability of relevant evidence was extremely low when we restricted studies to those studying biomes or taxonomic orders containing high percentages of threatened species, compared to the most frequently studied biomes and taxonomic orders. Further constraining the evidence by study design showed that only 17-20% of amphibian and bird studies used robust designs. Our results highlight the paucity of evidence on the effectiveness of conservation interventions, and the disparity in evidence for local contexts that are frequently studied and those where conservation needs are greatest. Addressing the serious global shortfall in context-specific evidence requires a step change in the frequency of testing conservation interventions, greater use of robust study designs and standardized metrics, and methodological advances to analyze patchy evidence bases.

ecology↗

bioRxiv2019

Insights from two decades of the Student Conference on Conservation Science

Conservation science is a crisis-oriented discipline focused on delivering robust answers to reducing human impacts on nature. To explore how the field might have changed during the past two decades, we analyzed 3,245 applications for oral presentations submitted to the Student Conference on Conservation Science (SCCS) in Cambridge, UK. SCCS has been running every year since 2000, aims for global representation by providing bursaries to early-career conservationists from lower-income countries, and has never had a thematic focus, beyond conservation in the broadest sense. We found that the majority of submissions to SCCS were based on primary biological data collection from local scale field studies in the tropics, contrary to established literature which highlights gaps in tropical research. Our results showed a small increase over time in submissions framed around how nature benefits people as well as a small increase in submissions integrating social science. Our findings also suggest that students and early-career conservationists could provide pathways to increased availability of data from the tropics and for addressing well-known biases in the published literature towards wealthier countries. We hope this research will motivate efforts to support student projects, ensuring data and results are published and made publicly available.

ecology↗

bioRxiv2019

The challenge of heterogeneous evidence in conservation

Conservation efforts to tackle the current biodiversity crisis need to be as efficient and effective as possible. To inform decision-makers of the most effective conservation actions, it is important to identify biases and gaps in the conservation literature to prioritize future evidence generation. We assessed the state of this global literature base using the Conservation Evidence database, a comprehensive collection of quantitative tests of conservation actions (interventions) from the published literature. For amphibians and birds, we investigated the nature of Conservation Evidence spatially and taxonomically, as well as by biome, effectiveness metrics, and study design. Studies were heavily concentrated in Western Europe and North America for birds and particularly amphibians. Studies that used the most robust study designs - Before-After Control-Impact and Randomized Controlled Trials - were also the most geographically restricted. Furthermore, there was no relationship between the number of studies in each 1x1 degree grid cell and the number of species, threatened species or data-deficient species. Taxonomic biases and gaps were apparent for amphibians and birds - some orders were absent from the evidence base and others were poorly represented relative to the proportion of threatened species they contained. Temperate forest and grassland biomes were highly represented, which reinforced observed geographic biases. Various metrics were used to evaluate the effectiveness of a given conservation action, potentially making studies less directly comparable and evidence synthesis more difficult. We also found that the least robust study designs were the most commonly used; studies using robust designs were scarce. Future research should prioritize testing conservation actions on threatened species outside of Western Europe and North America. Standardizing metrics and improving the robustness of study designs used to test conservation actions would also improve the quality of the evidence base for synthesis and decision-making.

ecology↗

bioRxiv2018

Captivity and exposure to the emerging fungal pathogen Batrachochytrium salamandrivorans are linked to perturbation and dysbiosis of the amphibian skin microbiome

O_LIThe emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal) is responsible for the catastrophic decline of European salamanders and poses a threat to amphibians globally.\nC_LIO_LIThe amphibian skin microbiome is strongly associated with disease outcome for several host-pathogen systems, yet its role in Bsal infection remains unresolved. In addition, many in-vivo Bsal studies to date have relied on specimens that have been kept in captivity for long periods without considering the influence of environment on the microbiome and how this may impact the host response to pathogen exposure.\nC_LIO_LIWe characterised the impact of captivity and exposure to Bsal on the skin bacterial and fungal communities of two co-occurring European newt species, the smooth newt (Lissotriton vulgaris) and the great-crested newt (Triturus cristatus).\nC_LIO_LIBsal infection and subsequent mortality in both newt species was associated with perturbation of the skin microbiome and possible dysbiosis. In addition, reduced microbial diversity and changes in microbiome structure accompanied the transition of newts from the wild to captivity, suggesting a possible decline in microbe-associated protection and increased risk of infection by opportunistic pathogens.\nC_LIO_LIOur findings advance current understanding of the role of host-associated microbiota in Bsal infection and highlight important considerations for ex-situ amphibian conservation programmes.\nC_LI

ecology↗