Using Citizen Heritage Science to Monitor Remote Sites Before and During the First COVID-19 Lockdown: A Comparison of Two Methods

ABSTRACT

This paper proposes citizen heritage science as an effective method to gather reliable data for monitoring and documenting heritage sites. For large heritage organisations the monitoring and documentation of sites in their care presents considerable challenges; continual monitoring of smaller, unstaffed, and more remote sites is often not practical. However, heritage sites are often popular destinations that receive high levels of visitors who carry increasingly sophisticated mobile phones. It seems logical that heritage organisations capitalise on using visitors’ images to record and monitor remote heritage sites. We compare two methods for data collection: a ‘guided’ approach, in which on-site signage prompts visitor submissions; and an ‘open’ approach, in which the public is asked to send any photographs they have of the site in question. We analyse the different results in collected data from these two approaches and hope to encourage heritage institutions to set up similar projects.

KEYWORDS:

• Remote monitoring
• conservation
• surveying
• participatory methods
• crowdsourcing
• historic environments

Introduction

Citizen science involves enlisting groups of untrained volunteers to participate in and contribute to scientific research. Crowdsourcing and citizen science are often used interchangeably, however there is a difference between the two. Crowdsourcing involves engaging a group of people within any project that utilises contributions from non-subject experts, be it through collecting or analysing data. Citizen science projects are the same, with the exception that they have a focused scientific outcome and engage non-subject experts in some point of the scientific process (Blaser 2014; Heigl et al. 2019). Citizen heritage science is the practice of engaging communities and individuals with scientific understanding of heritage. Examples of this are projects such as Micropasts (Bonacchi et al. 2014) and Rekrei (formerly Project Mosul) (Vincent et al. 2015), which used crowdsourced images to create digital facsimiles of heritage artefacts, utilising citizen heritage scientists for both data collection and analysis. Using satellite imagery volunteers helped identify fossils across East Africa as well as pinpoint possible locations for the tomb of Genghis Khan across the Mongolian steppe (Wilson 2018; Lin 2010). Citizen science has been used in heritage and archaeological sites in many ways. It can assist in heritage disaster management and publicly created datasets on photo sharing sites such as Flickr can be utilised to better understand community values of heritage (Kumar 2020; Kyi, Tse, and Khazam 2016; Figueroa-Alfaro and Tang 2017). Research has shown that social media can be used to build awareness among local communities of their heritage sites which can ultimately build social capital needed to protect these sites (Constantinidis 2016; Gregory 2015). Peer-to-peer platforms, like DigVentures, have also enabled civic engagement in archaeological research (Wilkins 2020). Citizen science is also a valuable tool used to transcribe, process, and discover myriad types of metadata contained within collections, as can be seen in projects such as Transcribe Bentham, Old Weather, What's on the Menu and Monitoring the ANZACs to name a few (Causer and Terras 2014; Romeo and Blaser 2011; Ridge 2014). Whilst projects such the Coastal and Intertidal Zone Archaeological Network (CITiZAN) and the Scottish equivalent Scottish Coastal Heritage at Risk have had great success in utilising volunteers to monitor remote heritage sites in danger, there are comparatively few citizen science projects involving collecting data for heritage science (Hambly 2017).

The lockdowns implemented in response to the COVID-19 crisis had a diversity of effects on citizen science projects globally (Basile et al. 2021). Published evidence shows a reduction of participation in projects that require mobility, such as the recording of animals on roads (Dörler and Heigl 2021) or spatial mapping of bird species (Rose et al. 2020). At the same time, other types of projects received increased participation, for instance when citizen scientists could make observations on their own gardens (Rose et al. 2020) or when scientists responded creatively with new projects suited to social isolation (Van Haeften et al. 2021). Another trend reported in several studies is an increase of submissions but a reduction of data quality (Sánchez-Clavijo et al. 2021) due to a sampling bias, with less data being collected in non-urban areas (Basile et al. 2021). To the best of our knowledge, there are no published observations of the effects of lockdown in citizen science projects in a built heritage context, but it is reasonable to expect similar trends.

The citizen science project on which this research is based, Monument Monitor, involves visitors of heritage and archaeological sites in monitoring their condition. Visiting heritage sites is a highly popular pastime in the UK; in England, 73% of the population visited a cultural heritage site in 2018 (Department for Digital Culture Media and Sport 2019) whilst in Scotland 75% of the population were actively engaged with cultural heritage (Director-General Constitution and External Affairs 2020). Citizen science projects that involve the collecting of data thrive when they are closely aligned to popular leisure activities. Participants can contribute to real scientific research whilst maintaining their current hobby. Some of the best-known large-scale citizen science projects involving data collection are aligned with environmental conservation, such as e-Bird (Kelling et al. 2015) and Budburst (Johnson 2016). Similarly, the large social interest in heritage in the UK represents considerable untapped potential for monitoring heritage sites. With Monument Monitor, visitors can act as sensors using their mobile devices, recording one-off events or ongoing phenomena that would not otherwise be monitored without a regular presence at the site.

Within heritage science, environmental and observational monitoring is key to ongoing care. However, individual object monitoring cannot always be completely uniform; national heritage institutions often have a large portfolio of sites in their care spread over a large geographical area. Smaller and unstaffed sites such as cairns, standing stones, and ruined churches often receive comparatively fewer visits from conservation and management teams, but are popular walking sites for locals. At such sites, long-term trends, one-off events, and seasonal changes can go unnoticed or undocumented. While camera traps can be used for monitoring, at scale this introduces a significant cost and security implications to any remote monitoring project. It removes the possibility of serendipitous discovery, in which issues that are unknown to heritage managers can be reported and addressed. Additionally, in many countries the installation of the required structures is restricted.

A key decision when setting up a citizen science project is the level of guidance and direction given to citizen scientists. In the case of monitoring historic sites, there are a range of options, from requesting images of specific aspects of a site at a certain time, place, and angle, to requesting any image, from any time, that the participants find useful. Recent research has established that smartphone cameras can be used quantitatively to measure a variety of issues in heritage such as biological growth, erosion, and one-off events such as vandalism (Harley et al. 2019; Brigham et al. 2018; Wess 2017; Barbero-Alvarez, Menéndez, and Rodrigo 2020). At the other end of this spectrum, we find the analysis of the wealth of useful historical reference data stored in personal photographs of popular sites. These can be used to qualitatively study the changing use of a site over time, as recently done by English Heritage in the exhibition ‘Your Stonehenge, 150 years of personal photographs’ (English Heritage 2019). These two methods yield different types of data, but it is not clear whether they result in different types of engagement. Furthermore, they have never been compared by using both methods to explore the same problem.

Unlike other citizen heritage science projects, such as SCAPE and CITiZAN, Monument Monitor did not initially actively recruit participants. Instead, visitors to the site were prompted to submit digital conservation data (photographs) through signage. This utilises the interested site attendee, or ‘visitor-as-sensor’, to document patterns that may otherwise go unnoticed between visits from professionals. When the first COVID-19 lockdown was imposed in the UK, participation in Monument Monitor was drastically reduced. A new approach to data collection was trialled in which participants were actively recruited to send in any images of the case study sites through requests in the media and press outreach. This provided an opportunity to comparatively evaluate two types of engagement: a ‘guided’ approach in which participants are directed to take and submit photographs that fit certain specifications through signage, and an ‘open’ approach, in which participants respond to an open call for photographs through public channels. The results of both methods are discussed in this paper through analysis of the results as well as discussions resulting from two focus groups held with project stakeholders within Historic Environment Scotland. We aim to show how changing aspects of a citizen science setup can affect engagement with and the subsequent outcome of a project.

Methodology

Project Setup and Case Study Sites

This paper will focus on submissions from two sites within the Monument Monitor project: the Machrie Moor Standing Stone Circles and Clava Cairns, described in Table 1 and shown in context in Figures 1 and 2, respectively. These sites were selected as they are most similar in terms of the size and rural location of both sites, estimated visitor numbers, and image submissions. This means that differences in the collected data will more likely reflect the data collection method and not particular aspects of the site.

Figure 1. Sign placed at Machrie Moor Stone Circles (left) and submissions showing flooding levels (right).

Figure 2. Sign placed at Clava Cairn (left) and submissions showing erosion over time (right).

Table 1. Selected characteristics of the case study sites.

Site name	Estimated visitor numbers per year	Site land area (m^2)	Element for monitoring
Machrie Moor Standing Stones	50,000	807	Water pooling
Clava Cairns	90,000	200	Stone movement, erosion

The Machrie Moor Standing Stones, situated on the Isle of Arran, includes six stone circles built around 2000 BCE. Due to the topography of the area, the site is prone to flooding, especially in the furthermost and middle circles. The site is set within an archaeologically significant landscape: numerous standing stones, cists, cairns, and the foundations of a Bronze Age hut, which are representative of different aspects of prehistoric life, can all be found in the immediate surroundings, and it is highly likely there are significant amounts of buried archaeology in the area. The conditions in which buried archaeology is preserved are sensitive to disturbance; small alterations could trigger deterioration mechanisms by disturbing the equilibrium of the system which has protected them until now (Daly 2011). To better understand this, and in consultation with heritage managers, images of evidence of visible waterlogging at the site were requested from visitors to understand the scale of the issue across the seasons.

Clava Cairns is a Bronze Age cemetery complex comprised of hut circles, standing stones, chambered cairns, and field systems. Situated near the Culloden Battlefield and linked to a popular TV series Outlander, the site has enjoyed an increase in visitors since 2014. As a result, parts of the site have started eroding noticeably around cairn entrances, with visitors even treating the site with light-fingered contempt (BBC 2017). As such, heritage managers requested images to document these areas of the site, as well as any stone movement that may be the result of nighthawkers or vandals.

Both the open and guided approaches described below were used at each site.

Guided Submissions

Signs were placed at each site to prompt visitors to take and submit photographs to the project, using either email, WhatsApp, Twitter, or Instagram. Visitors were prompted to use the hashtag ‘#monumentmonitor’ alongside the name of the site to assist in identification. Individual signs were created for each location, as different aspects were to be monitored at each site. Different wording was used for each sign, chosen in discussion with site managers focusing on a specific issue. At Machrie visitors were requested to document groundwater flooding, the reoccurrence of which is currently undocumented. Signs were placed at the entrance of circle three and six. Visitors were requested to ‘take a photo of the circles from the sign’, thus giving some degree of unity to the submitted images.

At Clava Cairns the site manager was keen to see how visitors experienced the site as well as documented any stone disturbance. As such, visitors were asked to take photos of the cairns ‘from different angles’ to ‘monitor the effects of ground erosion, graffiti and stones being moved’.

Open Submissions

Following the UK-wide lockdown arising from the COVID-19 pandemic in spring 2020, a public campaign, ‘Monument Monitor at Home’ was started which requested members of the public to submit any photographs they had of the case study sites. This campaign began with a blog published by Historic Environment Scotland on 14 August 2020 (Brigham 2020), with ten articles published in a variety of national newspapers, and three articles in history magazines (History Scotland 2020; Boag 2020), as well as social media. There was a particular focus on Clava Cairns and Machrie Moor Standing Stone Circles as it was more likely that the general public would have heard of and visited them. It was found that Clava Cairns was of particular media interest, due to the connection with the television show Outlander (Mair 2020). As such, most of the press coverage garnered from the campaign focused on Clava, which is also reflected in the submission results.

Categorising of Submissions

In the following analysis each photograph constitutes an individual submission; thus, if one person were to submit 30 photographs it would count as 30 submissions from one participant. Throughout this project, submitted images were sorted manually: images with unsuitable content, such as those containing faces, were categorised as ‘unsuitable’ and images in which the site could not be recognised were categorised as ‘unidentified’. Duplicate data was also removed as well from the multiple Twitter and Instagram accounts which were used to promote the project. This is because they were re-posts of other submissions, created to publicise the work of the project.

Images were also categorised according to their usefulness or relevance for remote monitoring. As Ma et al. commented, an advantage of using citizen scientists to collect data is that it does not necessarily matter if most images are unusable, as long as enough are submitted in the required time scale (Ma et al. 2015). Thus, images were tagged with a ‘useful’ category if they adhered to certain requirements laid out by site managers and other project stakeholders within Historic Environment Scotland. In ascertaining the percentage of useable images at each site, estimates can be made regarding the numbers of submissions required for different monitoring purposes as the project progresses. At Clava, photographs had to contain a clear view of either a cairn entrance, to effectively measure ground erosion, or evidence of one-off events or unauthorised works such as stone displacement, vandalism, or littering. At Machrie, relevant images had to include a clear view of the third and sixth circles in the complex, to monitor levels of groundwater flooding, or show evidence of unauthorised works or one-off events.

Focus Groups

Two focus groups were held throughout the project with heritage stakeholders. The purpose of these was to present early results from the project and receive feedback from members across the heritage organisation Historic Environment Scotland as to whether the collected data would be useful with their working practices. The first session was carried out in February 2020, and the second in February 2021 (online). Participants attended from across Historic Environment Scotland, including archaeologists, site managers, district architects, digital documentation managers, interpretation managers, and the technical and communication teams.

Results

Guided submission numbers were related to the seasonal trends of tourism in Scotland and wider national guidelines during the COVID-19 pandemic. Submissions steadily accumulated once the signs were placed on-site in September 2019, as seen in Figure 3. The popularity of Machrie Moor, the final sign to be installed, is evident by the spike in submissions through September and October, a popular time for visitors, being the off-peak ‘shoulder season’ for tourism in Scotland. February 2020 saw successive storms across the country and less data were submitted than in the previous month. Participation started to rise throughout March 2020 but was quickly curtailed on 16 March 2020, when the UK government advised against all non-essential travel amidst the COVID-19 global pandemic. Ticketed sites were shut to stop the spread of COVID-19 and on 23 March 2020, a nationwide lockdown was imposed. The effect of diminished submission levels can clearly be seen in Figure 3, especially when comparing guided submissions between June 2019 and the spring of 2020. Though Scottish government guidance permitted outdoor exercise once per day, people could not travel over five miles for leisure until 3 July 2020. As such, throughout this lockdown period, the only guided submissions received across the wider project were from sites that were unstaffed and situated in more urban areas, i.e. those which were readily accessible. Being quite remote, Machrie Moor and Clava Cairns received fewer submissions. Rates of submission via social media channels dropped considerably, with 25% of submissions being made through social media, down from 39% pre-lockdown. As the summer lockdown was lifted, submissions increased substantially as people took the opportunity to travel around the country and holiday in the remaining summer months.

Figure 3. Submission and participation rates at Clava and Machrie, showing low numbers of submissions through the winter of 2019 and spring of 2020 when the national lockdown was introduced.

The ‘Monument Monitor at Home’ campaign was launched on 14 April 2020, with a blog and successive articles in the national press. As Figure 3 shows, this led to a 10% increase in overall submissions, the majority of which were historical photographs. Whilst guided submissions are often sent in within weeks of being taken, most of the open submissions were many years old, as shown in Figure 4. Though dependent on the wording of the campaign request, this indicates the usefulness of the open method for gathering historical data. However, open submissions relied heavily on public engagement through traditional media channels. Figure 5 shows high levels of submission after each publication which quickly dwindled.

Figure 4. Length of time between site visit and photo submission with open and guided approaches. Open images are often submitted after a much longer period of time than guided.

Figure 5. Submissions over spring 2020 lockdown period with press publication dates showing large number of submissions immediately following press coverage.

Submissions were categorised as useful or relevant for the conservation priorities identified at each site outlined above (monitoring erosion/flooding). Relevant submissions at both sites were of high enough frequency to carry out monitoring and analysis. Comparatively fewer overall submissions for Clava were considered relevant, with roughly 4% of both open and guided submissions (Figure 6). At Machrie Moor however, the split is much larger. Considerably more guided images were appropriate for analysis (26.3%) whilst only 1.7% of open submissions were relevant according to the principles outlined above.

Figure 6. Perceived ‘usefulness’ of images, showing that guided submissions have a higher rate of perceived ‘usefulness’ as judged by site managers.

Participants often submitted multiple photographs for each site. Guided submissions would often feature the more ‘picturesque’ features of the site, along with aspects prompted through signage. This means that the overall percentage of relevant submissions is low for both sites. However, most participants submitted at least one relevant photograph for analysis. The exception is for open submissions at Machrie Moor, for which only 3.8% of images were relevant.

In both focus groups it was widely considered that the project was successful at gathering data for monitoring purposes, especially at the sites discussed in this paper. At both Clava and Machrie, sufficient photographs of a high enough quality were submitted to observe the aspects being monitored; levels of water pooling have been successfully mapped at Machrie Moor from 2018 to 2021.

The project successfully alerted managers to numerous instances of heritage crime and natural disasters. In August of 2020, a tree fell onto one of the chambered cairns during a storm, which was subsequently reported the next day. At several other Monument Monitor sites littering, stone movement, and damaging campfires have also been reported. In each of these cases, there was not a scheduled visit from a conservation professional planned for at least a week but through public participation, action was taken much sooner. In instances where an incident such as vandalism or littering had been reported to the management team though another means, the database was often consulted to pinpoint exactly when it may have occurred.

There were also several submissions reporting a heritage crime which actually were far from it. Numerous photographs submitted of Machrie Moor were from visitors worried that stones have been moved from the site. After an investigation it was found that the culprit was the local sheep, who had scratched a hole into the perimeter of one of the stone circles to shelter from the wind. Improved signage is now being considered to reassure visitors.

Focus group participants valued positively the usefulness of the project during lockdown. Most staff who maintained and cared for the properties were furloughed throughout the spring and summer. In some cases, the only monitoring occurring at the properties were those carried out by visitors contributing to Monument Monitor. When staff returned, they were able to consult the submissions to understand how the properties fared whilst they were unable to attend to them for routine work. Historic images that were submitted were found to be very useful to build a wider picture of the site in understanding previous conservation practices in cases with limited visual records.

Discussion

Digital documentation is a vital part of preventative conservation and offers a sustainable and scalable approach to the registration and management of conservation information (Jouan and Hallot 2020). While pioneering activities such as the Rae Project in Scotland (Historic Environment Scotland 2020) and HeritageCare (Masciotta et al. 2019) in southern Europe are leading examples of large-scale digital conservation methodologies, they rely heavily on professionals providing all documentation and monitoring data. Using the methodology discussed here, heritage institutions can capture long-term trends and one-off events between site visits from conservation professionals. This is a novel method of scientific investigation within heritage and is particularly pertinent immediately following the COVID-19 pandemic. It can be used to supplement other methods of documentation that cannot be carried out due to national or local restrictions, such as those caused by the COVID-19 pandemic. It has been shown to be an effective method to engage the public with conservation issues at heritage sites and provide them with an element of agency in their care.

Visitors responded positively to the requests to send in data, both on site and from press outreach. The open method is well suited for gathering historical data. Open submissions from Clava Cairns dated back to the 1960s and clearly showed visitors enjoying the site through the subsequent decades. These images have provided site managers with a solid baseline for the current conditions. They provided a valuable historical resource in visually recording different management approaches that are otherwise missing from conservation records. This method also proved to be a useful catalyst to engage the public at a time during which heritage sites were inaccessible to many. Many images were submitted with fond memories and anecdotes about their visit as well as consternation about the issues the sites face, particularly erosion across Clava Cairns. This methodology has a double positive by engaging communities with the conservation issues alongside collecting reference data. Similar outreach often helps ascertain the social value of heritage (Jones 2017; Bonacchi et al. 2019), and can be used within a toolkit of other approaches (Robson 2020). Further research is needed to examine critically the benefits and drawbacks of this method of engagement in comparison with others. The nature of engagement via social media results in a lack of direct contact with participants, which makes qualitative research difficult. The first challenge for future projects should be to complement the data collection with evidence of the participant’s experience, using surveys or interviews. This evidence will enable an evaluation of the engagement outputs of different kinds of scientific participation, either using online platforms, in-situ photography, or more involved hands-on experiments. Only then will it be possible to determine how this methodology can be used alongside other engagement approaches to maximise its social and scientific values. In a recent paper, Sauermann et al. (2020) categorised scientific views of citizen science projects into two types: ‘productivity’, in which the main rationale for involving volunteers was resource-orientated, and ‘democratisation’, in which projects contextualise research within society and allow contributors to take more agency within the scientific process. The methods described in this paper can be argued to align with both. Whilst utilising the visitor-as-sensor is a resource-motivated activity, it is also one that allows for a certain amount of agency to the visitor. Data was gathered at both sites that, prior to the project, managers did not consider to be an issue. It was also agreed in both focus groups that the project had been successful in engaging visitors and the public with conservation issues, and at Clava especially reports of unauthorised works decreased, which was thought to be the result of visitors being made aware of monitoring at the site.

The issue of bias can clearly be seen in the relevance of images in the data. In ornithological surveys certain species were often overreported and others underreported; it being more exciting to report a rare bird, rather than to continually report a common one (Bonney et al. 2009). A similar phenomenon is apparent in this study, especially in historical images and those summitted via social media. It is perhaps unusual for a visitor to a site to take an image of groundwater pooling or erosion as a memento for visiting without being prompted; instead, they are more likely to capture the more picturesque elements of the site. At Machrie Moor, for example, submissions via Instagram mainly consist of photographs taken to show the beauty to the site to the contributors’ followers, with only one clearly showing the area requested from the signage.

Relevance is also affected by the signage instructions. Machrie has a much higher level of ‘relevant’ guided submissions than of Clava. This is likely due to the signage having more specific instructions which requested images of two specific circles. Standard images of the site rarely feature circle six. As it is somewhat removed from the main standing stone circles, visitors sometimes fail to reach it all together. As such, historical holiday snaps rarely capture the area and it was featured in only 1.7% of open submissions. However, 26% of guided submissions did feature the circle. The sign at Clava requested for images to be taken ‘around the site, including any stone disturbances’. The cairn entrances at Clava are particularly picturesque, and often feature in visitor photographs, shown in a more even distribution of relevance between both guided and open submissions. Therefore, both open and guided approaches are useful if the aspect to be monitored is a part of the ‘standard’ visitor image. However, a guided approach is more suitable where specific images are required of rarely photographed vistas.

This statistic can be useful for modelling the images required to monitor certain aspects. Roughly two in three and one in three participants respectively will submit useful images for monitoring using the guided method. An estimate can thus be made for how many participants need to submit images over the course of a week to continue effective monitoring. We have found that a relevant image is required twice a week to monitor groundwater pooling, thus at least three visitors need to participate every week at Machrie.

The open method relies heavily on public outreach and is particularly resource-intensive in terms of publicity, media, and social media management. This should be factored into citizen heritage science projects. Much less engagement is needed for the guided method as the signage is the catalyst for submission. While submission numbers through the open method were high, guided submissions are more sustained and this approach is better suited for ongoing monitoring.

The project successfully alerted the conservation team to numerous issues across the sites including two instances of heritage crime (vandalism and illegal camping) and several instances of littering. Heritage managers and project stakeholders were able to easily access the submissions and use them for their own analysis of ongoing trends at the sites. Both methods could be applicable to heritage sites.

Conclusion

Both a ‘guided’ and ‘open’ approach to citizen heritage science provides useful data for heritage managers and other stakeholders, which has been summed up in Table 2. As a multidisciplinary approach it can help with both scientific and heritage management questions. Guided images were submitted with enough frequency to monitor aspects such as erosion and flooding at both sites. The visitor-as-sensor successfully discovered numerous instances of events that would otherwise have gone unchecked between routine inspections. Whilst the COVID-19 pandemic negatively impacted the frequency of guided submissions, the open approach to data collection proved adequate at providing site managers with useful insights into how sites are enjoyed and were managed in the past, giving them visual references for past conservation practices. Alongside the merits of both approaches, it should be acknowledged that as these approaches are scaled up to include more sites and diverse management tasks, the logistical complexity and challenges of meaningful interpretation increase proportionally. In this regard, ‘guided’ approaches may be more sustainable as they lend themselves more readily to routine prescriptive analysis and AI-assisted decision making. In any case, obtaining quantitative information from the submissions is a complex problem that requires a customised data analysis solution. It is advisable that future implementations of this method at other sites begin with a pilot study that researchers can use to define the method of analysis and adjust data collection. It is unlikely that either of these methods alone can replace traditional conservation roles, and a nuanced approach should be taken in the implementation of similar projects. Expert knowledge is required to understand what leads the drivers of change and to appropriately care for the heritage sites. Furthermore, this methodology is unlikely to be suitable in regions with low smartphone ownership. However, both approaches to data collection presented in this paper have been shown to be effective at gathering supplementary information to inform heritage management practices, as well as engaging visitors with heritage preservation. In addition, we believe there is scope to apply this methodology to research heritage values and community ties to heritage. We believe there is much scope for future citizen heritage science projects and present this paper as a methodology for heritage institutions to set up similar projects and conduct further research.

Table 2. Summary of findings through open and guided methods.

	Guided	Open	Further Research
Data Quality	High, with largest proportion of ‘useful’ images for analysis.	Less high, unless the area being monitored is particularly ‘picturesque’.	Useful for one-off events and certain types of environmental monitoring. However, what are the limits of this data?
Frequency	Of high enough frequency during tourist low season, however, very low during national lockdown and winter.	Initially high levels of interaction after press coverage that quickly decline.	How would different types of heritage sites affect the frequency?
Information	Successful for reporting one-off events, such as vandalism.	Useful for historical reference, especially to see how visitors experienced the site in the past.	Can either of these methodologies be used to ascertain social values of heritage?

Data availability

The raw data consisting of images submitted by visitors is not available due to licence restrictions. The dataset derived from the analysis of the submitted images is available from the corresponding author on reasonable request.

Acknowledgments

The authors wish to acknowledge the ongoing support of the staff at Historic Environment Scotland, particularly in the communications, conservation, and management teams. Special thanks to Hugh Boag, Ryan Taylor, and George Mair for their work in publicising ‘Monument Monitor at Home’. The authors wish to thank all participants in the Monument Monitor project, without whom this work would not be possible.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported jointly supported by Historic Environment Scotland and the Engineering and Physical Sciences Research Council under grant EP/L016036/1.

Notes on contributors

Rosie Brigham

Rosie Brigham completed her PhD in Heritage Science, focusing on Citizen Science and Software Engineering at UCL last year and now works as a software engineer for a fintech startup.

Scott Allan Orr

Scott Allan Orr is a lecturer in Heritage Data Science at the UCL Institute for Sustainable Heritage. An engineer with broad interests, his research primarily uses data-driven approaches to further understanding and management of heritage, with a particular focus on the historic environment and climate change.

Lyn Wilson

Lyn Wilson is a heritage scientist and Head of Programme for Research and Climate Change at Historic Environment Scotland. Her research interests focus on the application of science and digital technologies in cultural heritage contexts.

Adam Frost

Adam Frost is a Senior Digital Documentation Officer at Historic Environment Scotland and part-time PhD candidate with the UCL Institute for Sustainable Heritage, researching wind-driven rain using computational fluid dynamics. Other research interests include applications and visualisation of 3D data for cultural heritage.

Matija Strlič

Matija Strlič is Professor of Heritage Science at the Institute for Heritage Science, University College London, with a keen interest in the interactions between heritage, its environments, and people.

Josep Grau-Bové

Josep Grau-Bové is an Associate Professor of Heritage Science, with research interests in citizen science, preventive conservation and environmental simulation.