Land take is defined as the conversion of natural or semi-natural land for urban and other artificial land uses (Decoville/Schneider 2015; Science for Environment Policy 2016; Marquard/Bartke/Gifreu i Font et al. 2020). It includes sealed as well as non-sealed areas and covers buildings, urban infrastructure, parks, and sport and leisure facilities.¹ The main drivers of land take are population growth and economic development (Colsaet/Laurans/Levrel 2018). The former is primarily related to a need for more housing, public facilities and transportation; the latter relates to new industrial and commercial sites, the competition between municipalities to attract more investment, and the prioritisation of economic development over environmental sustainability. Due to its implications for biodiversity loss, habitat fragmentation and ecosystem degradation, as well as climate change and increasing follow-on costs for infrastructure (Behnisch/Krüger/Jaeger 2022), land take has garnered significant attention from policymakers and researchers worldwide (Schatz/Bovet/Lieder et al. 2021). More than ten years ago, in 2011, the strategy paper “Roadmap to a Resource Efficient Europe”, for example, set the target at EU level to continuously reduce land take and achieve no net land take by 2050 (EC 2011).

Spatial planning and its instruments have long been recognised as crucial in steering urban development towards more sustainable and efficient spatial outcomes. Summarised under terms such as growth management, smart growth or urban containment, land-use planning regulations, zoning policies, development incentives and financial mechanisms are applied in many countries (Ewing/Lyons/Siddiq et al. 2022; Siedentop/Schmidt/Dunlop 2022). Against the backdrop of primarily market-driven settlement development, land-saving and the target of “no net land take” must, therefore, be seen in the legal context of public interventions (Bovet/Reese/Köck 2018; Lacoere/Leinfelder 2022).

Accordingly, in our study, we want to examine which instruments are currently being used to steer urban development and to work towards reducing land take and the EU’s no net land take target. Since municipalities are usually responsible for settlement development and decide on the use of planning instruments within the framework of multi-level planning systems (Reimer/Getimis/Blotevogel 2014), we concentrate exclusively on the local level. Consequently, regional planning instruments are not the focus of our study. Following the EU Soil Strategy for 2030, we employ the “Land Take Hierarchy” principles (avoid – reuse – minimise – compensate) as our analytical framework (EC 2021: 9). These principles provide a systematic approach to structuring and evaluating the planning instruments used. Methodically, we examine the status of implementation using an online survey of local planning authorities within the framework of a case-study design (Blatter/Haverland 2014).

Following the “Land Take Hierarchy” principles, Section 2 describes the status of research in the fields of reuse, minimisation and compensation. In Section 3, we describe the methodology used in the empirical study, the national framing and the starting situation of our case study. Section 4 lists the key findings, while Section 5 discusses these findings and the resulting requirements for further action. Section 6 presents the conclusions.

The European Commission describes the way to achieve the target of no net land take through a fundamental change in land use. The target is part of both the EU’s 7th Environmental Action Programme (EU 2013) and the EU Soil Strategy for 2030 (EC 2021). The European Union Soil Strategy provides a set of principles for a “Hierarchy of Land Take” that forms the basis for sustainable land-use practices. These principles include avoidance, reuse, minimisation and compensation. Avoidance means prioritising the prevention of land conversion, with a focus on preserving undeveloped and ecologically valuable areas. Reuse encourages the recycling of previously developed land, effectively reducing the need for further land take (BBR 2004; Cortinovis/Haase/Zanon et al. 2019). Depending on the context, terms such as infill development, (soft) densification, inner urban development and redevelopment are also commonly used (Listokin/Walker/Ewing et al. 2006; Dillmann/Beckmann 2018; Koch/Bilke/Helbig et al. 2018; Schiller/Blum/Hecht et al. 2021; Ehrhardt/Behnisch/Jehling et al. 2023). Minimisation is connected to greenfield development, which is considered a last resort and shall only be undertaken on land in a less favourable condition when there are no viable alternatives. Where land is taken up or sealed, compensatory and replacement measures should be implemented to minimise the loss of ecosystem services.

By prioritising reuse, the principles actively promote the efficient use of existing land resources. This minimises the need to encroach upon undeveloped lands, thereby curbing further habitat destruction and conserving biodiversity-rich areas. Empirical studies have shown that compact spaces have a positive impact on traffic volumes and mode choice, energy efficiency, infrastructure costs and economic productivity (for a summary discussion see Ahlfeldt/Pietrostefani/Schumann et al. 2018; Berghauser Pont/Haupt/Berg et al. 2021). However, reuse is not only about density specifications (e.g. housing units per hectare) and overall higher densities, but is also strongly linked to the development and qualification of urban green spaces (green recycling). In addition, climate-friendly mobility offers as well as cultural and social aspects have increasingly been taken into account in academic discussion and in practical implementation when planning inner urban measures (Selle 1999; Westphal 2008; Böhm/Böhme/Bunzel et al. 2016; Eichholz/Schoppengerd 2020).

Notwithstanding the advantages, there are numerous local challenges and obstacles to the successful implementation of inner urban measures. On the one hand, landowners may not be interested in further building development or selling undeveloped land for various reasons (Reiß-Schmidt 2018: 998). In addition, the European Central Bank’s low interest rate policy (at least until spring 2022) and dynamically rising land and housing prices have encouraged speculation, which have boosted land banking and inhibited the construction of (affordable) housing (Paccoud/Hesse/Becker et al. 2022; Goldman 2023). On the other hand, there are still municipalities that continue to designate new building land even though population development does not justify it (Söntges 2007). The reasons for this include inter-municipal competition for potential new residents as well as short- to medium-term economic benefits (Phelps/Wood 2011; Ultsch/Behnisch 2017). Furthermore, there are limits due to legal constraints (e.g. zoning, building regulations) and general requirements for healthy living and working conditions in inner-city areas, which stand in the way of ever further densification (BBSR 2020; Lacoere/Leinfelder 2022). Likewise, there is frequently a lack of acceptance of densification measures, which leads to protests and resistance among the urban population (Wicki/Kaufmann 2021).

To overcome these obstacles, numerous initiatives in the field of building culture (for instance from the Bundesstiftung Baukultur) have developed guidelines for municipal practice, describing consensual solutions for successfully implementing inner urban measures (BSBK 2018). Given the availability of increasingly small-scale geodata backed by key metadata, for several years now the use of (semi-)automated monitoring systems has been increasingly discussed in academia and practice to support inner urban development (Schmeer/Terfrüchte/Münter 2021; Ehrhardt/Eichhorn/Behnisch et al. 2022).

To achieve no net land take, it will be necessary to offset land take by renaturalising built-up areas elsewhere. In contrast to reuse, this perspective is new in both academic research and planning practice. Nevertheless, renaturation has gained importance in recent years as a possible strategy for adapting to demographic and economic decline as well as in the context of the increasingly dynamic discussion on degrowth (Herfert 2007; Xue 2022). The current lack of experience can be traced back, on the one hand, to the fact that renaturation measures are not financially attractive and, on the other hand, to the massive impact on property rights (BBSR/BMUB 2016; Hartz/Schaal-Lehr/Langenbahn et al. 2021). Moreover, planning law has predominantly developed in the context of capitalism, which has led to a growth-oriented planning paradigm. Therefore, the use of instruments for renaturation is unfamiliar to planners and does not enjoy broad public support (Xue 2022). In addition, the implementation of compensation mechanisms (“one in, one out”) raises a number of questions that have not yet been answered (BBR 2007; Hartz/Schaal-Lehr/Langenbahn et al. 2021): At what scale (national, regional, local) should compensation mechanisms be applied? How are the artificialised and renatured hectares measured? How is the ecological and agronomic value of lands taken into account since one hectare is not equivalent to another?

Based on the brief overview of the state of research, we are interested in the planning instruments that are currently being used to manage urban development and to work towards reducing land take and the EU’s no net land take target, and which obstacles hinder their implementation. Due to their more widespread use in academia, we refer to the following terms – inner urban development, land-saving construction and renaturation – in the remainder of this paper. In the following subsections, we describe, firstly, our online survey, secondly, the national framing, and thirdly, the case study in which we conducted our online survey.

3.3  The case of North Rhine-Westphalia

North Rhine-Westphalia is made up of 396 municipalities, many of which are large cities: 30 of Germany’s 80 cities with more than 100,000 inhabitants are located in North Rhine-Westphalia. In terms of numbers, small cities (20,000 to 100,000 inhabitants) and large towns (10,000 to under 20,000 inhabitants) dominate, respectively accounting for 179 (45.2 %) and 134 (33.8 %) of all municipalities. By contrast, the proportion of smaller municipalities in Germany as a whole is much higher. While housing and population densities vary greatly between cities and towns, cities are, on average, extremely dense, as shown for example by the federal government’s 2020 Urban Development Report (Stadtentwicklungsbericht) (BMI 2020). Questions about how to handle land in North Rhine-Westphalia must therefore be answered against the background of high housing densities. As a starting point for our empirical research, this section takes a closer look at land use development in North Rhine-Westphalian municipalities based on the following indicators:

–	population density (inhabitants per housing and transport area in hectares), and
–	the land used for housing and transport purposes as a share of a municipality’s total area (see Figure 1).

Figure 1  Residential development 2016-2019 in North Rhine-Westphalia in percent by size categories (N=391). Data Basis and Typlology of Cities: Spatial Monitoring System of the BBSR, Further Calculations by B. Adam

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In this respect, we need to take account of the 2016 reorganisation of land survey data which prevents any evaluation of longer time series. In addition, the results exclude five municipalities with conspicuous changes in their total land area or their housing and transport area. While further statistical inaccuracies in the comparison of individual municipalities cannot be completely ruled out, they are largely ironed out by the further aggregation (unweighted averages) into municipality types by size categories. For reasons of better readability, in the following, we refer to land use and land take for settlement and transport purposes as urban area and land take. An increase in a municipality’s urban area is understood as urban expansion. An increase in population density refers to an increase in the number of people living in an urban area over time (densification).

Aggregated by size categories, the results allow for a number of interpretations. The lower average population density – especially in smaller towns and rural districts – goes hand in hand with an increasing amount of urban area. Unless land take is primarily for transport, commercial or industrial purposes, it must be assumed that residential development has been more generous (i.e., less dense). This can be explained by a per capita increase in living space, but also by vacant buildings or more land-extensive new housing developments encroaching on green and recreational space. In fact, per capita living space has increased most in the smaller municipalities, i.e., where it was already particularly high (see Figure 2) and where urban sprawl and declining densities are dominant (see Figure 1).

Figure 2  Development of per capita living space in North Rhine-Westphalia and Germany 2011-2019. Data basis and Typlology of Cities: Spatial Monitoring System of the BBSR and German Federal Statistical Office (Destatis)

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It is noteworthy that there are many municipalities where, despite declining populations, land take is increasing just as much as in municipalities with growing populations. Conversely, irrespective of the size of municipality, there is a small subgroup of municipalities that are “constricted” from two sides, with increasing densification going hand in hand with above-average land take.

The findings provide an overview of the status quo regarding inner urban development, land-saving construction and renaturation in municipalities in North Rhine-Westphalia. They show that in all three fields implementation levels for achieving no net land take vary widely. In line with the findings of Ehrhardt, Eichhorn, Behnisch et al. (2022), larger municipalities in North Rhine Westphalia draw on a higher number of (planning) instruments in the three fields studied. The findings indicate that the need for action with regard to sustainable housing development is higher in such municipalities and that they have more manpower available, thereby necessitating and enabling an overall more differentiated use of instruments.

Looking at inner urban development, the evaluation shows that other urban fields of action have hardly been conceptually linked to the goal of inner urban development. However, greater integration of inner urban development into other urban concepts offers the opportunity to better utilise synergies between urban planning fields that substantively overlap and to raise awareness for the importance of increased inner urban development (Eichhorn/Rusche/Weith 2021).

Planning departments, especially in towns, not only have to deal with often conflicting goals from civil society and policymakers in the field of inner urban development, but also have to make do with a lack of human resources (Blum/Atci/Roscher et al. 2022: 155). The findings suggest that, under these conditions, municipalities often have to succumb to outside pressure, especially when current demand and policy objectives call for more houses to be built.⁸ Without carefully negotiated, spatially differentiated conceptual foundations, planning departments thus often find themselves exposed to the arguments and goals of investors and residents.

In such a scenario, the interaction of various instruments is decisive for assertive and high-quality inner urban development. This includes continuous and systematic monitoring able to transparently capture the status of inner urban development. While more and more municipalities are now mapping developments (Blum/Atci/Roscher et al. 2022: 16), there is still a need to catch up in terms of systematic assessments of the status quo. Digitalisation continues to offer a great deal of potential, as yet inadequately tapped (Ehrhardt/Behnisch/Jehling et al. 2023).

The findings indicate that new housing developments in North Rhine-Westphalia tend to be planned and implemented with low densities. In line with Ammann, Brack, Claßen et al. (2021: 46–50), therefore, land-saving construction continues to play a secondary role, especially in smaller municipalities. However, for housing development to be land-saving, the goal must be to make new land take more efficient, including in more rural areas (Schmeer/Terfrüchte/Münter 2021). A core demand is therefore to achieve a commitment to higher housing densities overall, leading to the share of new housing developments that solely feature detached or semi-detached houses declining in planning practice. Since it can be assumed that owning a house will remain the core housing model for the wider public in the long term, attempts should be made to meet the desire for individual forms of housing within the framework of community-oriented housing concepts, which allow higher densities (Schubert/Büttner/Lindmaier et al. 2021: 29–30). Such housing concepts must be geared to town and city centres and railway station catchment areas. On the one hand, it is easier to realise higher densities in city and town cores – due to existing housing densities –, while on the other hand the spatial proximity of environmentally friendly modes of transport has a demonstrably positive influence on the choice of means of transport and the modal split (Eichhorn/Gerten/Diller 2021). According to the survey findings, acceptance is a sine qua non for all these measures, meaning that it is of particular importance for local policymakers and civil society to be made aware of the need for higher densities. One possible starting point here is the dissemination of best practice examples and illustrations of densified housing projects (Schubert/Büttner/Lindmaier et al. 2021: 29–30).

Unlike the 30-ha target, the net-zero target is not just about limiting the amount of land take, but also about balancing land take and renaturation (“one in, one out”). This means that – in addition to inner urban development and land-saving outer urban development – renaturation measures are moving into much sharper focus. In accordance with Janssen, Rubel, Schulze et al. (2016) and Hartz, Schaal-Lehr, Langenbahn et al. (2021), the findings show that urban planning departments remain unfamiliar with the concept of renaturation, with only a few municipalities having any concrete experience of it. Renaturation areas should be selected in such a way that they match spatial planning and urban development objectives. Housing structures and transport infrastructures which have become dysfunctional over time can be adapted to current requirements and past urban planning shortcomings can be eliminated through renaturation. Since, however, renaturation incurs high costs without generating any direct financial gain, it is imperative that land take is linked to renaturation, i.e., land take must always be offset by land renaturation elsewhere. The costs for renaturation must be borne by those behind the planning and construction measures causing land take. The instruments required for implementing this approach need to be coordinated among all administrative levels – in the sense of multilevel governance – and could be applied analogously to the “one in, one out” regulation under nature conservation law (Eingriffs-Ausgleichs-Regelung). The fundamental need to expand the existing set of instruments is recognised by the majority of respondents. At the same time, developers need to make a contribution to renaturation, at least in correspondence with their share of land take.

The findings show that municipalities in North Rhine-Westphalia are not (yet) in a position to consistently implement a no net land take policy. The current conglomeration of conflicting interests, especially the balancing act between urgently required housing construction and open space protection, does not make this any easier. Though the instruments needed are defined in existing law (Building Code) and widely known concepts (integrated and specialised for urban development), their uptake by municipalities is as yet insufficient to implement a successful no net land take policy. Efforts to make municipalities with sufficient development potential more aware of land-saving construction, or to gain citizen acceptance for neighbourhood densification through enhanced participation schemes, have as yet been limited.

If the goal, under the current conditions of population growth in Germany (84.1 million inhabitants in 2022 with an upward trend), is indeed to move towards no net land take, municipalities will have to be better empowered, i.e., enabled to use existing tools even without direct pressure to act (as in some large cities or metropolitan districts).

The Building Code calls for precedence to be given to inner urban development. What is missing is a substantive orientation from policymakers as to how the land potential is to be assessed from a multidimensional perspective. The survey revealed, for example, that municipalities now tend to identify a potential for inner urban development, but rarely evaluate it. Density thresholds or orientation values for shares of open spaces are currently of little use due to a lack of specifications in § 1a BauGB or the exemptions still listed in § 34 BauGB.

While higher densities – through densification or in the context of urban expansion – are unavoidable, they can only be achieved if additional (recreational) amenities, e.g. in the form of green spaces, sports areas and/or meeting areas for the general public, are also planned. The latter aspect relates to healthcare and adaptation to climate change, but also to the urban and architectural design requirements enshrined in § 1 (5) BauGB. In some places, alliances have already been formed within the population to do this, especially when generational shifts create demand for denser, more community-oriented forms of housing.

So far, experience with renaturation has been at best ad hoc. Against this background, no net land take policy constitutes a fundamental paradigm shift in urban and regional planning. In addition to legally binding requirements, an intensive dialogue between municipalities, specialist planning departments and other stakeholders is of key importance. Model projects or simulations can be particularly helpful in testing (new) (planning) instruments and procedures under scientific supervision. The development of a reliable system for monitoring the land take/renaturation balance is also gaining in importance.

Continuing population growth on the one hand and restrictions on land take on the other will inevitably lead to shortages and ultimately to price increases. It is therefore necessary to create appropriate instruments to ensure “socially just” land use, inevitably these must be sought outside current planning law.