Since the 2012 conference, proceedings have been produced in digital format. These are available online at https://iale.uk/conferences, with prior proceedings published in paper format and papers from the 2014 conference published in an edited book (Francis et al. 2016). We compiled a database by reviewing a total of 914 abstracts of oral and poster presentations published in available conference proceedings since 1992. We characterised abstracts using pre-defined classes within eight categories (Table 2) with the categorisation allowing an abstract to be labelled as more than one class/category. Where authorship was divided among several authors the lead author’s organisation was used for classification purposes. Similar approaches have been used to examine trends in publications across the discipline in Landscape Ecology journal (Andersen 2008; Wu 2017) and specifically at US-IALE conferences (McIntyre et al. 2013). We acknowledge that the outcome of our analysis will reflect the categories used, but by selecting categories based on our prior knowledge of ialeUK conferences and used previously by other reviews we are able to both ensure coverage of content within the UK and enable comparison beyond.
To understand how the composition of contributors to ialeUK conferences has changed we recorded Author Affiliations and considered possible variations in landscapes by identifying the focal Landscape Type investigated in each study. We included a Methods category to explore trends in landscape ecology approaches and, to consider how the spatio-temporal scope of studies may have varied, we included Spatial Extent and Temporal Extent categories. Focal topics of abstracts were characterised using Organism, Concepts and Other Concepts categories. Multiple classes in each category could be assigned to any abstract, depending what was deemed appropriate by the reviewer. Below we focus on trends in these categories through time but also highlight what seem to be the clearest patterns in the data, with brief commentary on what the primary drivers might be. A more complete analysis of the database is freely available (Millington 2019).
The total number of conference abstracts initially increased through time, from 19 in the first conference to a peak of 71 a decade later in 2002 (Table 1). Abstracts in each conference then decreased until the later 2000s, becoming relatively stable at around 40 abstracts each year. This contrasts with US-IALE which increased attendance during the 1990s to a point which has remained relatively stable since (McIntyre et al. 2013). While the exact reasons for the recent decline in participation in ialeUK conferences are difficult to confirm they are likely related to an increase in competing conferences (e.g. those organised by IALE-Europe), decline in meeting attendance from regulatory and statutory bodies for the environment that were often key contributors in the earlier years (e.g. Natural England), and popularity of conference themes in any given year. This recent average of 40 abstracts per conference reflects the preferred format of single-group sessions of 15 min-long oral presentations over two days, often with an additional half-day of fieldtrips. The composition of contributions has not showed consistent trends over time: some years are notably distinct in one or more aspects of their composition (Fig. 1), such as Landscape Type in 2005/06 and 2014/15 (Fig. 1b), Organism in 2002 (Fig. 1c), Method in 1992 and 1997 (Fig. 1d), and Temporal Extent in 2005, 2010 and 2012. These differences are associated with the conference theme of a given year. The single-group session format adopted likely makes them more prone to this variation in composition compared to larger conferences with a multi-session format (e.g. US-IALE).
The increase in total conference contributions through the 1990s was driven by a growing number of academic contributions, leading to a relative decrease in the proportion of contributions from governmental agencies (Fig. 1a). However, since the mid-2000s the absolute number of contributions from Government authors has declined (mean of 17 pre-2005, mean of 6 post-2004), while contributions from NGOs has increased slightly (mean of 4 pre-2005, mean of 6 post-2004). This seems to mirror the changing priorities of the UK government in moving away from strong centrally-funded statutory bodies to a more devolved model and the commensurate changes in job roles, organisational economics and the limited support for applied work beyond basic regulatory implementation (e.g. JNCC 2010). Across all years, Academic contributions dominate (55%) followed by Government (27%). Although Business contributors are present at many conferences, they represent only a small proportion (4%) and their contributions are almost exclusively non-empirical, possibly reflecting the costs of such studies.
Although there are no stark trends through time (Fig. 1a), there is a clear emphasis of some landscape types in individual years given the particular theme of the conference that year (i.e. Riverscapes in 2006, Urban in 2014 and Seascapes in 2015). Urban landscape types do not appear in the abstracts before 1998, which may reflect a change in UK politics in 1997 (Wilson and Hughes 2011) with new urban greenspace policy and targets developed by the newly elected government, such as England’s Accessible Natural Greenspace Standard (ANGSt; Handley et al. 2003), in line with a growing recognition of the benefits that parks, gardens and other urban greenspace provide (Wilson and Hughes 2011). While Lowland Rural landscape types generally provided the majority of studies before 2005, they have declined in recent years with a rise in the relative interest in other landscape types. However, across all years, Lowland Rural landscape types dominate conference contributions (41%), which is possibly not surprising given the effects of fragmentation, infrastructure, agricultural intensification and urban sprawl in these landscapes, but also given their relative prominence across the UK (e.g. Natural England 2014). The next largest group of studies does not define any specific landscape type, largely because these abstracts indicate a focus on multiple landscape types (rather than no landscape type being specified). Qualitative methods were applied to seascapes more than for any other landscape type; Green Infrastructure is studied mostly in Urban landscapes and Catchment-Based Approaches are seen most often in Riverscapes. By contrast, we were surprised to find that there are few representatives of Cultural Landscape studies (that is studies focussing on people’s behaviours, preferences or attitudes in association with the landscape) in Urban landscapes; this may reflect the perception of ialeUK conferences as being more science-focused, as opposed to culturally-oriented conferences hosted by other UK landscape organisations (e.g. the Landscape Institute).
Focal organisms of study have varied considerably through time (Fig. 1c), and, as for landscape type, localised peaks are associated with particular conferences (e.g. Birds in 2002 in which the conference theme was Avian Landscape Ecology). Even taking these peaks into account it is clear that some organism groups are not as well studied, including amphibians (2% of all abstracts), fish (2%) and reptiles (1%). Studies of plants were conducted over longer time periods (decades/centuries) while invertebrate studies were conducted over shorter periods (annual and monthly). There are very few studies of any organism over time periods shorter than Months (~ 0.005% of all abstracts). In terms of Author Affiliation, Bird studies tend to be dominated by NGOs reflecting the strength of such organisations focusing on bird conservation within the UK. Perhaps surprisingly, bearing in mind the obvious application of remotely sensed data for habitat monitoring, Plant studies infrequently used Remote Sensing Methods (0.5%). Unsurprisingly, invertebrates are dominated by applied ‘mini’ spatial extent studies (1 ha–10 km2), providing exemplars of sites and species within a spatially constrained landscape context at scales appropriate for their life history strategies.
Most of the studies presented were Empirical and Quantitative (58% of all abstracts). In early conferences, studies were often dominated by Empirical methods (in the sense of collecting and analysing primary data; mean of 43% 1992–2002), but since 2007 they are a minor contributor (mean of 17% 2008–2017; Fig. 1d). This decrease may be related to the costs of empirical study, potentially to the decrease in Government contributors research in UK landscape ecology (as noted above), and increases in use of modelling (quantitative methods have remain consistently used) and secondary or monitoring data used with GIS (see below). In later years the distribution of methods has evened-out and there has been a noticeable increase in Qualitative methods, many of which focused on Socio-Economic dimensions and Cultural Landscapes, a trend that has not been noted in previous reviews (e.g. McIntyre et al. 2013, Wu 2017). This increase may be associated with the rise of the ecosystem services framework, and efforts to improve methodologies which capture cultural and non-use values (Chan et al. 2012, Hernández-Morcillo et al. 2017). Across years there is surprisingly little in the way of Remote Sensing (RS) being used (3% of all abstracts) while use of Geographic Information Systems (GIS) increased from low levels of application pre-2005 to now remaining steady at around 20% of abstracts each year. The seemingly continued low use of RS may be because authors have classified it under the umbrella term of GIS, with methods frequently employed together and managed by software packages that integrate both techniques. The increase in use of GIS is consistent with greater application across the discipline, although relative to Landscape Ecology publications examined by Andersen (2008) there was seemingly a lag in the uptake in UK landscape ecology behind that in other regions (at least in terms of work presented at ialeUK conferences). Particularly noteworthy is that despite the increasing presence of Ecosystem Services at conferences, there are relatively few examples of Empirical studies of the concept.
Across all abstracts in all years, studies at Intermediate spatial extents have dominated. That is, Local (10–100 km2) studies (28% of all abstracts, 32% when undefined extents are excluded) and Regional (1000–10,000 km2) studies (20% and 24%), with fewer at larger (> 10,000 km2) and fewest at smaller (< 10 km2) spatial extents. This dominance of the Intermediate spatial extent reflects the landscape scale of the UK, with its unusual diversity of landscapes over such scales. Through time there are no clear trends or changes in the spatial extent of studies (as found by Andersen 2008 for studies across the discipline 1987–2005), although Local studies peak in 2014 (59%) which was the year of the Urban-themed conference (Fig. 1e). The large proportion of Local studies in that year then makes sense given the vast majority of urban areas in the UK are smaller than our definition of Local (i.e. ≤ 100 km2; ONS 2017). The smallest extents (micro and mini) have the largest proportions of Biodiversity studies and these are often closely linked to the behavioural scales of the organism under study. However, such smaller extents are not seen in those studies examining Socio-Economic aspects of landscapes. All extents demonstrate consistent proportions of Management and Conservation studies reflecting the importance of that broad topic area as a key driver in the development and application of UK landscape ecology.
The majority of abstracts (65%) did not report the duration of their study. Given the spatial emphasis of most landscape ecology studies this is unsurprising, but in future more detail on the temporal dimension of studies needs to be encouraged. Of those studies that did report a duration, in most years the majority of studies operated over time periods of Years or longer (Fig. 1f). It was also notable that studies of Urban landscapes were over shorter durations (Months and Weeks) when compared with other landscape types.
Across all abstracts reviewed, the most frequent concepts addressed were Land Use/Cover Change (20%), Connectivity/Fragmentation (19%) and Spatial Analysis and Modelling (17%). However, while absent in earlier conferences, Climate Change and Ecosystem Services have become regularly studied in recent years (composing 13% and 37% of conference abstracts since 2010, respectively; Fig. 1g), a pattern that has been observed elsewhere (McIntyre et al. 2013; Wu 2017). In contrast, whereas McIntyre et al. (2013) found that connectivity has been consistently represented at US-IALE conferences and despite a rise in connectivity research as reported by some studies (e.g. in urban contexts, Crooks and Sanjayan 2006; LaPoint et al. 2015, and more generally), the proportional representation of Connectivity/Fragmentation studies has decreased over the past 25 years of ialeUK meetings. This may be explained by the increasing popularity of other concepts (see Other "Concepts" section) and also a much wider knowledge and understanding of fragmentation to the point where it has become ‘mainstream’ in conservation and management, certainly in the case study-type material frequently presented at ialeUK conferences. Studies of Ecosystem Services had the smallest proportion of Empirical studies, the largest proportion of Global extent studies, and fewest Mini and Micro studies.
Of all the work presented at conferences, studies considering Management and Conservation and Biodiversity compose the majority (56%), both comprising relatively large proportions of Connectivity and Fragmentation studies. Studies addressing Biodiversity have generally decreased through time as a proportion of conference contributions, with commensurate increases in Socio-Economic and Planning studies since the mid-2000s (Fig. 1h). This perhaps reflects a move towards concepts such as ecosystem services, scenario visualisation (as captured in Qualitative/Cultural Landscapes categories) and seascapes, as opposed to earlier conferences focused on more biodiversity-weighted themes of species dispersal (1997) or birds (2002). Biodiversity and Management and Conservation studies also have greatest proportions of Empirical methods and lowest proportions of Theoretical approaches. Across the other concepts we considered, Biodiversity studies examined a relatively large proportion of Invertebrates. Despite methods in landscape ecology being strongly relevant, Invasive Pests have been examined very infrequently at ialeUK conferences (considered in only 1% of abstracts). Throughout the concepts we considered, both Micro and Macro studies are not well represented with (as elsewhere) Decadal timescales dominating.
Just as there are numerous writings on the trajectory of landscape ecology as a discipline (including variation in the rate of change and specific emphases between regions, for example Farina (2000); Antrop (2007); With (2019)), there are numerous ways that we might summarise and characterise UK landscape ecology from our brief analysis of conference abstracts. Antrop (2007) charted writings on landscape ecology as a shift from an initial dominance of descriptive approaches towards spatial modelling and simulation. Our observed decline in studies using empirical methods that collect and analyse primary data may match such a shift away from a descriptive approach, but the use of landscape pattern metrics for description has never been as strong an issue in the UK as it has been elsewhere (e.g. China, Fu and Lu 2006). However, notwithstanding the influence of individual conference themes, studies of urban and cultural landscapes have increased recently at ialeUK meetings and in this the UK shares some of the emphases of landscape ecology in Asia (e.g. Hong et al. 2010). The scale and longevity of human occupation also means that landscape ecology in the UK is characterised more by work within the European tradition of concern about character and the human role in shaping landscapes than a North American perspective of humans as a disturbance factor (sensu Antrop 2007). Similarly, understanding the role of traditional and indigenous knowledge is less prominent in UK landscape ecology than in other regions where industrialisation occurred later (e.g. Asia; Hong et al. 2010) or where European cultures displaced or disrupted others’ (e.g. Meurk and Swaffield 2000 in NZ, Waller and Reo 2018 in USA).
Recently, Wu (2017) highlighted several ‘hot topics’ in the discipline over the last decade; landscape genetics, urban landscape ecology, ecosystem services and landscape sustainability. A key trend we observe at ialeUK meetings is the decrease in studies examining Biodiversity and Connectivity/Fragmentation versus increases in Socio-Economic, Climate Change and Ecosystem Services studies. It may be that the apparent decrease in studies of the more ‘traditional’ issues are because they are now being considered within more contemporary contexts associated with the increasingly transdisciplinary nature of landscape ecological research and the global challenges being faced in the twenty-first Century (Naveh 2007). But not all newer issues in landscape ecology have been represented at ialeUK conferences. For example, although we did not include ‘landscape genetics’ as a concept in our data collection (and so it cannot be explicitly analysed in our data), the choice of concepts was driven by our a priori knowledge of conference content and anecdotally we know that although this is a fruitful area of landscape research (as also demonstrated by Manel et al. 2003) there has been very limited attention given to the issue at ialeUK conferences. Whilst the reasons are unclear it perhaps reflects the more ecological forums in which colleagues working in landscape genetics are presenting their research in the UK, e.g. the British Ecological Society Annual Conferences. Similarly, the traditions of landscape ecology in Europe have been more influenced by land-use planning and the management of cultural landscapes as compared to the more ecological landscapes focus in North America (With 2019). Yet, despite omission of some topics that are growing elsewhere in the discipline, in general we see our analysis as providing evidence that UK landscape ecology does reflect broader shifts across the discipline, particularly with respect to the importance of climate change, ecosystem services, an understanding how landscapes are connected within a globalised world (e.g. Plieninger et al. 2016) and how we can help meet sustainability challenges under rapid environmental change (Naveh 2007).