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Abstract Public policy addressing biodiversity loss is most likely to be effective when it is informed by appropriate evidence and considers potential unintended consequences. We evaluate key evidence relating to the Hunting Trophies (Import Prohibition) Bill that was discussed in the UK Parliament between 2022 and 2024. We characterize the UK's role in international hunting trophy trade by analyzing CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) trade data for 2000–2021 and 2015–2021. For CITES‐listed species imported to/exported from the UK as hunting trophies in these periods we use data from the International Union for Conservation of Nature (IUCN) Red List of Threatened Species to determine whether hunting designated as “trophy hunting” is (i) likely a major threat contributing to species being of elevated conservation concern, (ii) likely or possibly causing localized declines, or (iii) not a threat. We then use the Red List to determine whether such hunting provides, or potentially provides, benefits for species and/or people. Finally, we evaluate the UK Government's impact assessment of the bill. In 2000–2021 an estimated 3494 hunting trophies from 73 CITES‐listed species and subspecies were exported to the UK involving an estimated 2549 whole organism equivalents (WOEs), that is, individual animals. Imports involved 158.86 ± 66.53 (mean ± SD) trophies/year (115.83 ± 32.27 WOEs/year). In 2015–2021, 79% of imports were from countries where populations of the hunted species are stable, increasing, or abundant. Legal hunting for trophies is not a major threat to any of the species or subspecies imported to the UK, but likely or possibly represents a local threat to some populations of eight species. This hunting does, or could potentially, benefit 20 species and subspecies, and people. Among other concerns, the impact assessment failed to adequately consider the costs and benefits to local communities in countries where such hunting occurs. Informed by these analyses we discuss alternative regulatory options.

Abstract Strawberry or red leopards are a rare colour morph of leopard (Panthera pardus) characterised by spot markings that are red or brown instead of black, thought to be a result of a mutation in the tyrosinase‐related protein (TYRP1) gene. We report the first record of this phenotype on the African continent outside of South Africa, from Selous Game Reserve in southern Tanzania. One female leopard with strawberry colouration was documented out of 373 individual leopards (0.3%) identified through camera trap surveys conducted from 2020 to 2022 over a combined area of more than 4600 km2 in the Nyerere‐Selous landscape.

Abstract Introduction In South Africa, the HIV care cascade remains suboptimal. We investigated the impact of small conditional financial incentives (CFIs) and male‐targeted HIV‐specific decision‐support application (EPIC‐HIV) on the HIV care cascade. Methods In 2018, in uMkhanyakude district, 45 communities were randomly assigned to one of four arms: (i) CFI for home‐based HIV testing and linkage to care within 6 weeks (R50 [US$3] food voucher each); (ii) EPIC‐HIV which are based on self‐determination theory; (iii) both CFI and EPIC‐HIV; and (iv) standard of care. EPIC‐HIV consisted of two components: EPIC‐HIV 1, provided to men through a tablet before home‐based HIV testing, and EPIC‐HIV 2, offered 1 month later to men who tested positive but had not yet linked to care. Linking HITS trial data to national antiretroviral treatment (ART) programme data and HIV surveillance programme data, we estimated HIV status awareness after the HITS trial implementation, ART status 3 month after the trial and viral load suppression 1 year later. Analysis included all known individuals living with HIV in the study area including those who did not participated in the HITS trial. Results Among the 33,778 residents in the study area, 2763 men and 7266 women were identified as living with HIV by the end of the intervention period and included in the analysis. After the intervention, awareness of HIV‐positive status was higher in the CFI arms compared to non‐CFI arms (men: 793/908 [87.3%] vs. 1574/1855 [84.9%], RR = 1.03 [95% CI: 0.99−1.07]; women: 2259/2421 [93.3%] vs. 4439/4845 [91.6%], RR = 1.02 [95% CI: 1.00−1.04]). Three months after the intervention, no differences were found for linkage to ART between arms. One year after the intervention, only 1829 viral test results were retrieved. Viral suppression was higher but not significant in the EPIC‐HIV intervention arms among men (65/99 [65.7%] vs. 182/308 [59.1%], RR = 1.11 [95% CI: 0.88−1.40]). Conclusions Small CFIs can contribute to achieve the first step of the HIV care cascade. However, neither CFIs nor EPIC‐HIV was sufficient to increase the number of people on ART. Additional evidence is needed to confirm the impact of EPIC‐HIV on viral suppression.

Abstract Background Precision oncology, using comprehensive biomarker testing (cBT) to inform individual cancer diagnosis, prognosis and treatment, includes increasingly complex technology and clinical data sets. People impacted by cancer (patients and caregivers) and healthcare professionals (HCPs) face distinct challenges in navigating the cBT and personalized treatment landscape. This review summarizes evidence regarding cBT‐related communication between people impacted by cancer and HCPs and identifies important avenues for future research in precision oncology. Methods A scoping review was conducted using records published in PubMed during January 2017–August 2022, focusing on the breadth of topics on patient‐HCP communication and knowledge resources used by HCPs as guidance in cBT‐related communication. Data were extracted from records meeting inclusion criteria, and findings were summarized according to main topics. Results The search identified 287 unique records and data were extracted from 42 records, including nine from expert input. Most records originated from the United States included patients with different types of cancer, and oncologists were the main HCPs. Patients' motivation for undergoing cBT and receiving results was generally high in different settings. However, patients' understanding of cBT‐related concepts was limited, and their knowledge and information preferences changed based on cBT implications and significance to family members. HCPs were valued by patients as a trusted source of information. Limited evidence was available on HCPs' information‐seeking behavior and factors influencing cBT‐related knowledge and confidence, often self‐reported as insufficient. Conclusions Patient education by knowledgeable and confident HCPs, information management and a caring patient‐HCP relationship communicating continuity of care regardless of cBT results are crucial to empower patients and shared decision‐making in precision oncology. More data on the process and structure of cBT‐related communication, distinction between and characterization of different timepoints of patient‐HCP interactions are needed.

Abstract Illegal trade in big cat (Panthera spp.) body parts is a prominent topic in scientific and public discourses concerning wildlife conservation. While illegal trade is generally acknowledged as a threat to big cat species, we suggest that two enabling factors have, to date, been under‐considered. To that end, we discuss the roles of human‐felid conflict, and “local” use in illegal trade in big cat body parts. Drawing examples from across species and regions, we look at generalities, contextual subtleties, ambiguities, and definitional complexities. We caution against underestimating the extent of “local” use of big cats and highlight the potential of conflict killings to supply body parts.

Introduction This report is intended to provide insight into the presentation, diagnosis, and treatment of prostatic sarcomas. A literature review is included to compare variables in demographics, histology, prognosis, and treatment strategies among previously reported incidences. Case presentation In this case, we have a 72‐year‐old man who initially presented with symptomatic nephrolithiasis that led to further workup. Magnetic resonance imaging revealed an enlarged, heterogeneous prostate with a dominant mass in the left lobe. A biopsy of the prostate revealed a high‐grade, undifferentiated sarcoma in the left lobe along with concomitant adenocarcinoma in the right lobe. Conclusions The patient underwent a radical prostatectomy, which according to existing literature remains the most effective treatment strategy. Staging is the most important prognostic indicator, making this cancer particularly dangerous as presenting symptoms are highly variable among patients.

Abstract Reconciling conflicts between wildlife conservation and other human activities is a pervasive, multifaceted issue. Large carnivores, such as the African lion Panthera leo are often the focus of such conflicts as they have significant ecological and cultural value but impose severe social and financial costs on the communities that live alongside them. To effectively manage human–lion conflict, it is vital to understand stakeholder decision‐making and preferences regarding mitigation techniques and coexistence strategies. We used a novel experimental game framed around lions and livestock protection, played across eight villages in Tanzania, to examine stakeholder behaviour in response to three incentive structures: support for non‐lethal scaring, and individual‐ and community‐level subsidies for provision of wildlife habitat. We found that non‐lethal deterrent methods were the preferred mitigation strategy and that individual subsidies most increased the provision of wildlife habitat. Subsidies that were conditional on other community members' decisions were less effective at increasing habitat choices. Player characteristics and attitudes appeared to have little influence on game behaviour. However, there was some evidence that gender, wealth, perceptions of respect, and the behaviour of other players affected decision‐making. Achieving success in managing conservation conflicts requires genuine stakeholder participation leading to mutually beneficial results. Our findings suggest that, while incentive‐based instruments can promote pro‐conservation behaviour, these may be more effective when targeted at individuals rather than groups. We demonstrate how experimental games offer a practical and engaging approach that can be used to explore preferences and encourage discussion of conflict management. Read the free Plain Language Summary for this article on the Journal blog.

Abstract Conserving large carnivores requires protecting landscape spaces that encompass all spatiotemporal scales of their movement. Large carnivores normally roam widely, but habitat loss and fragmentation can constrain their movement in ways that restrict access to resources and increase encounters with humans and potential conflict. Facilitating carnivore population coexistence with humans across landscapes requires conservation plans informed by patterns of carnivore space use, particularly at the human–wildlife interface. We sought to understand lion space use in Laikipia, Kenya. We conducted a path‐selection function analysis using GPS collar data from 16 lions to assess patterns of space use across a range of spatial scales (sedentary to home range expanses; 0, 12.5, 25 and 50 km) and temporal scales (day, dusk, night and dawn). Path‐selection results were then incorporated into space use maps. We found that most landscape features influenced path‐selection at the broadest spatial scale (50 km), representative of home range‐wide movement, thereby demonstrating a landscape‐wide human impact on lion space use. We also detected sub‐diurnal variation in lion path‐selection which revealed limited space use during daylight hours and increased space use overnight. Our results highlight that optimal support for human–lion coexistence should be temporally adaptive at sub‐diurnal scales. Furthermore, spatial approaches to lion conservation may be better generalized at broad spatial scales so that land management plans can account for home range patterns in lion space use.

In Part I of our review of cancer outcome research, we analysed pros and cons of various measures relevant to quantifying the burden of cancer. Based on our recommendations in Part I, we now discuss in Part II opportunities and priorities in four areas of outcome research: primary prevention; early detection screening; treatment; and quality‐of‐life assessment. We recommend the establishment of an infrastructure that facilitates high‐quality research in these areas: (a) progress in primary prevention can be assessed most directly by monitoring cancer incidence although the interpretation of temporal trends is notoriously confounded by numerous factors that complicate causal inference. (b) preventive screening, with the aim to prevent advanced disease, appears to work well in in some tumours but not in others. It will require randomized control trials (RCTs) to quantify benefits and harms although conclusive studies are increasingly difficult to undertake. We therefore propose learning screening programmes (randomization at the time of rolling out population‐based programmes) as the most feasible approach. (c) New therapeutic interventions tailored to the individual patient often require assessment in RCTs with rather complex and dynamic structure, making their design and analyses increasingly challenging but also more suited to be executed as academic, PI‐initiated trials. (d) We next discuss assessment of quality‐of‐life aspects. Quality of life is a neglected component in outcome research with an urgent need for development, validation and standardization. We finally recommend four initiatives that would pave the way for a valid and informative assessment of the goals for improved cancer control in Europe as defined by the European Academy of Cancer Sciences.

Abstract Human activities are altering ecological communities around the globe. Understanding the implications of these changes requires that we consider the composition of those communities. However, composition can be summarized by many metrics which in turn are influenced by different ecological processes. For example, incidence‐based metrics strongly reflect species gains or losses, while abundance‐based metrics are minimally affected by changes in the abundance of small or uncommon species. Furthermore, metrics might be correlated with different predictors. We used a globally distributed experiment to examine variation in species composition within 60 grasslands on six continents. Each site had an identical experimental and sampling design: 24 plots × 4 years. We expressed compositional variation within each site—not across sites—using abundance‐ and incidence‐based metrics of the magnitude of dissimilarity (Bray–Curtis and Sorensen, respectively), abundance‐ and incidence‐based measures of the relative importance of replacement (balanced variation and species turnover, respectively), and species richness at two scales (per plot‐year [alpha] and per site [gamma]). Average compositional variation among all plot‐years at a site was high and similar to spatial variation among plots in the pretreatment year, but lower among years in untreated plots. For both types of metrics, most variation was due to replacement rather than nestedness. Differences among sites in overall within‐site compositional variation were related to several predictors. Environmental heterogeneity (expressed as the CV of total aboveground plant biomass in unfertilized plots of the site) was an important predictor for most metrics. Biomass production was a predictor of species turnover and of alpha diversity but not of other metrics. Continentality (measured as annual temperature range) was a strong predictor of Sorensen dissimilarity. Metrics of compositional variation are moderately correlated: knowing the magnitude of dissimilarity at a site provides little insight into whether the variation is driven by replacement processes. Overall, our understanding of compositional variation at a site is enhanced by considering multiple metrics simultaneously. Monitoring programs that explicitly incorporate these implications, both when designing sampling strategies and analyzing data, will have a stronger ability to understand the compositional variation of systems and to quantify the impacts of human activities.

Abstract Expert elicitation can be valuable for informing decision‐makers on conservation and wildlife management issues. To date, studies eliciting expert opinions have primarily focused on identifying and building consensus on key issues. Nonetheless, there are drawbacks of a strict focus on consensus, and it is important to understand and emphasize dissent, too. This study adopts a dissensus‐based Delphi to understand conflict among dingo experts. Twenty‐eight experts participated in three rounds of investigation. We highlight disagreement on most of the issues explored. In particular, we find that disagreement is underpinned by what we call “conflict over values” and “conflict over evidence.” We also note the broader role played by distrust in influencing such conflicts. Understanding and recognizing the different elements shaping disagreement is critical for informing and improving decision‐making and can also enable critique of dominant paradigms in current practices. We encourage greater reflexivity and open deliberation on these aspects and hope our study will inform similar investigations in other contexts.

Abstract While almost half of all mammal species are rodents, records of albinism in free‐ranging rodents are very rare. Australia has a large and diverse assemblage of native rodent species, but there are no records of free‐ranging albino rodents in the published literature. In this study, we aim to improve our understanding of the occurrence of albinism in Australian rodent species by collating contemporary and historic records of this condition and providing an estimate of its frequency. We found 23 records of albinism (i.e., a complete loss of pigmentation), representing eight species, in free‐ranging rodents native to Australia, with the frequency of albinism being generally

Abstract The UK government is considering legislation to prohibit the importation of hunting trophies. We examine documented social, ecological, and political outcomes of two previous such bans. We find that the UK government's proposal shares the shortcomings of existing bans that have (1) failed to address, or have even amplified, key threats to hunted species, (2) imposed costs on citizens of other countries, and (3) delegitimized the Convention on International Trade in Endangered Species (CITES). Trophy import bans are blunt policy instruments that can cause more problems than they solve.

Abstract Natural history documentaries are a globally important source of information about wildlife, conservation and environmental issues, and they are the closest many will get to seeing featured animals and their behaviour in the wild. They are entertainment, certainly, but may also inform people's knowledge of the natural world and influence their ideas on conservation of species and habitats. We locate our perspective in the existing literature analysing wildlife documentary making and its effects. We argue that a conspicuous pre‐occupation with the ‘personalisation’ of individual animals and the injection of false jeopardy in recent wildlife documentaries leads to significant misinformation and creates problems for public understanding of wider conservation. We illustrate our point by detailing episodes from the BBC natural history series Dynasties, discussing personalisation, anthropomorphism and the use of jeopardy to gain emotive impact and audience engagement. We find that narratives are framed around a single individual, that ‘stories’ are framed as soap operas, that jeopardy is emphasised throughout and that animals are endowed with the capacity to be aware of, and work towards, the dynasties of the title. With conservation increasingly relying on public support, we argue that it is important that people are presented with factually correct information, and portraying wild animals as soap opera style characters is neither honest nor helpful. A free Plain Language Summary can be found within the Supporting Information of this article.

In a mission that aims to improve cancer control throughout Europe, the European Academy of Cancer Sciences has defined two key indicators of progress: within one to two decades, overall cancer‐specific 10‐year survival should reach 75%, and in each country, overall cancer mortality rates should be convincingly declining. To lay the ground for assessment of progress and to promote cancer outcomes research in general, we have reviewed the most common population‐based measures of the cancer burden. We emphasize the complexities and complementary approaches to measure cancer survival and the novel opportunities for improved assessment of quality of life. We propose that: incidence and mortality rates are standardized to the European population; net survival is used as the measure of prognosis but with proper adjustments for confounding when temporal trends in overall cancer survival are assessed; and cancer‐specific quality of life is measured by a combination of existing questionnaires and utilizes emerging communication technologies. We conclude that all measures are important and that a meaningful interpretation also requires a deep understanding of the larger clinical and public health context.

Abstract Although social media is growing rapidly as a news source, including for disseminating conservation information, studies comparing attention given to differing threats to species on social media are almost non‐existent. As the amount of attention given to differing threats can influence what people perceive to be important and impact the formation of environmental policies, it is vital that conservationists understand which issues are being discussed online. Using elephants (Loxodonta Africana, Loxodonta cyclotis, and Elephas maximus) as test species, we conducted a content analysis of tweets about elephants posted to Twitter during 2019. According to the global conservation authority, the International Union for Conservation of Nature, the most pressing threats to the conservation of wild elephant populations are habitat loss, human‐elephant conflict, and poaching, with the magnitude of each threat differing between the three species of elephants. Our Twitter analysis revealed that these major threats were infrequently discussed, with habitat loss being the most infrequently discussed (

Abstract Accurate and precise estimates of population status are required to inform and evaluate conservation management and policy interventions. Although the lion (Panthera leo) is a charismatic species receiving increased conservation attention, robust status estimates are lacking for most populations. While for many large carnivores population density is often estimated through spatially explicit capture–recapture (SECR) applied to camera trap data, the lack of pelage patterns in lions has limited the application of this technique to the species. Here, we present one of the first applications of this methodology to lion, in Tanzania's Ruaha‐Rungwa landscape, a stronghold for the species for which no empirical estimates of status are available. We deployed four camera trap grids across habitat and land management types, and we identified individual lions through whisker spots, scars and marks, and multiple additional features. Double‐blind identification revealed low inter‐observer variation in photo identification (92% agreement), due to the use of xenon‐flash cameras and consistent framing and angles of photographs. Lion occurred at highest densities in a prey‐rich area of Ruaha National Park (6.12 ± SE 0.94 per 100 km2), and at relatively high densities (4.06 ± SE 1.03 per 100 km2) in a community‐managed area of similar riparian‐grassland habitat. Miombo woodland in both photographic and trophy hunting areas sustained intermediate lion densities (1.75 ± SE 0.62 and 2.25 ± SE 0.52 per 100 km2, respectively). These are the first spatially explicit density estimates for lion in Tanzania, including the first for a trophy hunting and a community‐managed area, and also provide some of the first insights into lion status in understudied miombo habitats. We discuss in detail the methodology employed, the potential for scaling‐up over larger areas, and its limitations. We suggest that the method can be an important tool for lion monitoring and explore the implications of our findings for lion management.

Abstract Compared to controlled laboratory conditions, plant growth in the field is rarely optimal since it is frequently challenged by large fluctuations in light and temperature which lower the efficiency of photosynthesis and lead to photo‐oxidative stress. Plants grown under natural conditions therefore place an increased onus on the regulatory mechanisms that protect and repair the delicate photosynthetic machinery. Yet, the exact changes in thylakoid proteome composition which allow plants to acclimate to the natural environment remain largely unexplored. Here, we use quantitative label‐free proteomics to demonstrate that field‐grown Arabidopsis plants incorporate aspects of both the low and high light acclimation strategies previously observed in laboratory‐grown plants. Field plants showed increases in the relative abundance of ATP synthase, cytochrome b6f, ferredoxin‐NADP+ reductases (FNR1 and FNR2) and their membrane tethers TIC62 and TROL, thylakoid architecture proteins CURT1A, CURT1B, RIQ1, and RIQ2, the minor monomeric antenna complex CP29.3, rapidly‐relaxing non‐photochemical quenching (qE)‐related proteins PSBS and VDE, the photosystem II (PSII) repair machinery and the cyclic electron transfer complexes NDH, PGRL1B, and PGR5, in addition to decreases in the amounts of LHCII trimers composed of LHCB1.1, LHCB1.2, LHCB1.4, and LHCB2 proteins and CP29.2, all features typical of a laboratory high light acclimation response. Conversely, field plants also showed increases in the abundance of light harvesting proteins LHCB1.3 and CP29.1, zeaxanthin epoxidase (ZEP) and the slowly‐relaxing non‐photochemical quenching (qI)‐related protein LCNP, changes previously associated with a laboratory low light acclimation response. Field plants also showed distinct changes to the proteome including the appearance of stress‐related proteins ELIP1 and ELIP2 and changes to proteins that are largely invariant under laboratory conditions such as state transition related proteins STN7 and TAP38. We discuss the significance of these alterations in the thylakoid proteome considering the unique set of challenges faced by plants growing under natural conditions.

Abstract As climatic conditions change, species will be forced to move or adapt to avoid extinction. Exacerbated by ongoing climate change, California recently experienced a severe and exceptional drought from 2011 to 2017. To investigate whether an adaptive response occurred during this event, we conducted a “resurrection” study of the cutleaf monkeyflower (Mimulus laciniatus), an annual plant, by comparing trait means and variances of ancestral seed collections (“pre‐drought”) with contemporary descendant collections (“drought”). Plants were grown under common conditions to test whether this geographically restricted species has the capacity to respond evolutionarily to climate stress across its range. We examined if traits shifted in response to the recent, severe drought and included populations across an elevation gradient, including populations at the low‐ and high‐elevation edges of the species range. We found that time to seedling emergence in the drought generation was significantly earlier than in the pre‐drought generation, a response consistent with drought adaptation. Additionally, trait variation in days to emergence was reduced in the drought generation, which suggests selection or bottleneck events. Days to first flower increased significantly by elevation, consistent with climate adaptation across the species range. Drought generation plants were larger and had greater reproduction, which was likely a carryover effect of earlier germination. These results demonstrate that rapid shifts in trait means and variances consistent with climate adaptation are occurring within populations, including peripheral populations at warm and cold climate limits, of a plant species with a relatively restricted range that has so far not shifted its elevation distribution during contemporary climate change. Thus, rapid evolution may mitigate, at least temporarily, range shifts under global climate change. This study highlights the need for better understanding rapid adaptation as a means for plant communities to cope with extraordinary climate events.

Abstract Achieving conservation goals, such as coexistence between wildlife and humans, requires an evidence‐based understanding of the factors that shape conservation contexts. For addressing conflict between humans and wildlife, this means understanding the barriers and opportunities to changing human behaviors toward wildlife. Here, we develop a Theory of Change (ToC) to promote coexistence between livestock producers and dingoes in Australia. The ToC is based on behavior change principles and interdisciplinary research identifying four key stakeholder groups who may influence dingo management. It employs four overlapping strategies to address these barriers: (a) a media campaign to promote public awareness of dingo management practices, which may result in pressure upon governments to restrict lethal control; (b) promoting more inclusive decision‐making processes, specifically including Aboriginal Australians; (c) monitoring and evaluation of the effects of dingo management on livestock and ecosystems to identify opportunities for nonlethal dingo management; (d) campaign to encourage adoption of nonlethal management methods by livestock producers based on an understanding of sociopsychological factors that shape behaviors. The framework is a tool for conservation advocates and policymakers to implement and monitor change that facilitates both wildlife conservation and thriving rural communities.

Abstract Aichi Target 12 of the Convention on Biological Diversity (CBD) contains the aim to ‘prevent extinctions of known threatened species’. To measure the degree to which this was achieved, we used expert elicitation to estimate the number of bird and mammal species whose extinctions were prevented by conservation action in 1993–2020 (the lifetime of the CBD) and 2010–2020 (the timing of Aichi Target 12). We found that conservation action prevented 21–32 bird and 7–16 mammal extinctions since 1993, and 9–18 bird and two to seven mammal extinctions since 2010. Many remain highly threatened and may still become extinct. Considering that 10 bird and five mammal species did go extinct (or are strongly suspected to) since 1993, extinction rates would have been 2.9–4.2 times greater without conservation action. While policy commitments have fostered significant conservation achievements, future biodiversity action needs to be scaled up to avert additional extinctions.

Abstract Species afflicted by multiple threats are thought to face greater extinction risk. However, it is not known whether multiple threats operate antagonistically, additively, or synergistically, or whether they vary across different taxonomic and spatial scales. We addressed these questions by analyzing threats to 10,378 species in six vertebrate classes at global and regional spatial scales using network analysis. The total number of threats was a poor predictor of extinction risk, and particular combinations of threats did not predict extinction risk in the same way at different spatial scales. The exception was cartilaginous fishes, which faced increased extinction risk with increasing numbers of threats. Except for cartilaginous fishes, our findings indicate that species facing more threats than others do not face a higher risk of extinction and suggest that effective conservation will require more investment in identifying how threats and different ecosystem stressors operate together at local scales.

Dysplastic nevi (DN) are common and controversial and the best choice for management of DN after diagnosis is not always clear. The presence of positive margins found on diagnostic biopsy is used by many dermatologists when deciding whether to re-excise these lesions. In order to quantify the predictive value of positive margins in diagnostic biopsies of DN, we performed a review and analysis of the concordance between the histological findings of biopsies and their subsequent excisions. A total of 122 pathology reports from diagnostic biopsies of DN with nevus cells present at the tissue margin were reviewed. Within this sample, 68 total postbiopsy excisions had been performed. The excisional pathology reports were reviewed for the presence of residual or recurrent nevus cells. Residual nevus cells were reported in 29 of 63 available excisional pathology reports illustrating a positive predictive value (PPV) of positive margins in diagnostic biopsies of DN of 46.0%. We present this value along with PPVs from the very few existing similar studies. The quantified predictive value of positive margins in diagnostic biopsies is useful information for providers who must make decisions regarding the best treatment options for patients with DN. The low PPV of positive margins lends further evidence that DN of moderate severity or less may simply be monitored.