Wild Equus® Field Study:
The Ecological Role of Horses and Ponies in Conservation Grazing
Long-Term Photographic Field Observations from Dartmoor
Field observations referenced in this study are based on continuous photographic and observational work conducted on Dartmoor between 2005 and present.
1. Introduction and Study Context
This field study presents a long-term observational account of the role of native ponies within a conservation landscape, based on fieldwork conducted on Dartmoor over a period exceeding 20 years.
The work is grounded in direct observation, supported by photographic documentation and aerial imagery, and is informed by a growing body of scientific literature relating to conservation grazing, vegetation dynamics, and ecosystem function.
Dartmoor represents a semi-natural upland system shaped by a combination of environmental processes and land management practices. Within this landscape, native ponies remain as free-ranging herbivores, interacting continuously with vegetation, soil, and terrain.
Over time, repeated field observations have identified consistent patterns in the behaviour and movement of these ponies, including selective grazing, the formation of pathways, and the use of specific areas within the landscape. These patterns appear to influence vegetation structure at both local and landscape scales.
The purpose of this study is to document and examine these observations within an ecological framework, and to consider how the behaviour of native ponies may contribute to conservation outcomes. The study does not seek to compare grazing systems or evaluate alternative management approaches, but rather to present evidence of the ecological role of equids based on direct observation and supporting research.
By combining long-term field observation with existing scientific evidence, this work aims to contribute to a clearer understanding of how native ponies function within conservation grazing systems, and how their presence may influence habitat structure and biodiversity over time.
2. Landscape Context and Vegetation Dynamics
Dartmoor is a semi-natural upland landscape characterised by a mosaic of heathland, grassland, and wetland habitats. Its ecological value is closely linked to the structure and composition of its vegetation, which in turn is influenced by climate, soil conditions, and long-term land use.
A defining feature of many areas of Dartmoor is the presence of purple moor grass (Molinia caerulea), a native species that can form dense, continuous areas where it dominates the ground under certain conditions. Where dominant, Molinia creates a uniform vegetation structure, limiting light availability at ground level and reducing opportunities for the establishment of other plant species.
Studies of upland systems have shown that increased dominance of Molinia is associated with reduced structural diversity and can inhibit the regeneration of key heathland species, including Calluna vulgaris (Fraser et al., 2019). This shift in vegetation structure has wider ecological implications, as habitat complexity is an important factor in supporting a range of plant and animal communities.
The distribution and dominance of Molinia are influenced by multiple factors, including soil moisture, nutrient availability, and grazing pressure. In the absence of sufficient disturbance or grazing, Molinia can expand, leading to increasingly homogeneous vegetation across the landscape.
More broadly, upland heathland systems rely on a degree of structural variation to maintain ecological function. Heterogeneous vegetation, including areas of short grass, taller swards, open ground, and regenerating heath, provides a range of niches that support biodiversity. This variation is not static but develops over time through the interaction of environmental processes and herbivore activity.
Field observations on Dartmoor indicate that areas of dense Molinia are often interspersed with patches of shorter vegetation and exposed ground. These variations in structure are not uniformly distributed, but instead occur in patterns that reflect both environmental conditions and the movement of grazing animals.
Understanding how these patterns emerge is central to interpreting the ecological processes operating within the landscape. In particular, the relationship between vegetation structure, disturbance, and grazing behaviour is a key factor in determining habitat condition and long-term ecological resilience.
3. Managed Landscape Context
Dartmoor is not an untouched landscape, but one that has developed over time through the interaction of natural processes and human management. Grazing has been a consistent presence within this system and remains one of the primary influences on vegetation structure and distribution.
Across upland environments, grazing is widely recognised as a tool that can influence plant communities, soil condition, and habitat structure. The effects of grazing are not uniform, but vary depending on factors such as grazing intensity, timing, species present, and local environmental conditions. As a result, vegetation patterns observed within the landscape reflect a combination of these influences rather than a single controlling factor.
In managed systems, grazing contributes to the regulation of biomass and can limit the expansion of dominant plant species. At the same time, insufficient grazing or disturbance may allow certain species, including coarse grasses, to increase in coverage, leading to more uniform vegetation structure over time. Conversely, higher levels of grazing pressure can reduce vegetation height and alter plant composition, demonstrating that outcomes are dependent on balance rather than presence or absence.
Within this context, grazing should be understood as one of several interacting processes shaping the landscape. Weather, soil conditions, hydrology, and historical land use all contribute to the patterns observed today. Grazing interacts with these factors, influencing how vegetation develops, recovers, and responds to change.
Field observations on Dartmoor indicate that grazing does not produce uniform outcomes across the landscape. Instead, variation is evident at multiple scales, with differences in vegetation height, density, and composition occurring within relatively small areas. These patterns suggest that grazing operates in a spatially variable manner, contributing to the development of heterogeneous habitats.
Understanding this managed context is important for interpreting the role of different herbivores within the system. Rather than viewing grazing as a single process, it is more accurately understood as a set of interactions that shape vegetation structure over time. Within this framework, the behaviour and characteristics of individual grazing species become relevant to how these patterns are formed and maintained.
4. The Role of Equids in Conservation Grazing
Before grazing pressure shapes the land, molinia dominates, forming dense, uniform stands with limited structural diversity.
Equids exhibit a set of behavioural and physiological characteristics that influence how they interact with vegetation and landscape structure. These characteristics shape their role within conservation grazing systems and contribute to the development of heterogeneous habitats over time.
Long-term field observations of Dartmoor ponies, recorded over a period exceeding 20 years, indicate consistent patterns of selective grazing and spatial use of the landscape.
Ponies have been observed to utilise areas of more palatable vegetation while leaving adjacent areas less intensively grazed. This pattern of use contributes to variation in vegetation height and composition, resulting in a patchwork of closely grazed and lightly grazed areas.
This spatial variation is associated with increased habitat complexity, which is widely recognised as an important factor in supporting biodiversity. Areas of shorter vegetation provide access and foraging opportunities for certain species, while taller areas offer cover and refuge, creating a range of ecological niches within relatively small spatial scales.
Although their diet is primarily grass-based, equids demonstrate the capacity to utilise a range of coarse and fibrous plant species. Field observations on Dartmoor indicate regular consumption of Molinia caerulea, along with sedges, rushes, and bramble. Seasonal browsing of woody vegetation, including gorse, has also been recorded. This dietary flexibility enables equids to utilise vegetation that might otherwise remain under used, contributing to the regulation of dominant plant species within the landscape.
In addition to grazing, the movement patterns of ponies contribute to ecological processes. Repeated observations indicate that ponies follow consistent routes across the moor, resulting in the formation of visible pathways within the sward. Early experimental work at Bellever demonstrated that targeted pony activity significantly reduced Molinia sward height, increased bare ground, and promoted the germination of heather seedlings, establishing the underlying mechanism for vegetation change (Leigh, 2018). Aerial photographic records from Bellever show that these pathways form an interconnected network across areas of dense molinia grass. These routes are not random, but develop through repeated use over time, reflecting patterns of movement between grazing areas, shelter, and water sources.
Trampling associated with movement has been observed to influence ground conditions, including the exposure of small areas of bare soil and the compression of vegetation. These disturbed areas may facilitate seed to soil contact and provide conditions suitable for the establishment of certain plant species. Research conducted at Bellever, through a collaboration between the Dartmoor Pony Heritage Trust and Plymouth University, has identified that such areas are associated with the establishment of Calluna vulgaris (Lunt et al., 2021), suggesting a potential role in supporting heathland regeneration.
At Bellever, Dartmoor, a long-term conservation grazing study has demonstrated the scale of this effect. Grazing by Dartmoor ponies was associated with a 31-fold increase in the number of common heather seedlings, alongside a 9% reduction in the percentage cover of Molinia grass. In addition, the ponies reduced the average height of Molinia tussocks and increased the extent of bare ground within the sward. Further study identified a significant difference in the condition of mature heather plants, with 79% of plants recorded as healthy in grazed areas compared to an average of 43% in non-grazed plots (Lunt et al., 2021).
Longer-term monitoring at Bellever has shown that these changes develop over time, with sustained reductions in Molinia dominance, increased bare ground, and improvements in heather condition recorded across multiple years (Richards, 2020). More recent monitoring has shown that pony grazing continues even in the absence of active encouragement, with repeated visitation and established movement patterns indicating that grazing behaviour has become embedded within the landscape (Westwood, 2023). This repeated use of specific areas reinforces localised disturbance and contributes to the development of pathways and vegetation mosaics across the site.
Comparable observations have been reported in other systems. A study of semi-wild horse grazing in the Côa Valley, Portugal, found that horse grazing contributed to the regulation of grass height and supported the maintenance of open habitats, while also influencing plant community composition (Ribeiro et al., 2025). The study also noted that grazing by horses may contribute to habitat conditions favourable for certain insect groups, linked to changes in vegetation structure.
Collectively, both field observations and published studies indicate that equids influence conservation landscapes through a combination of selective grazing, movement, and disturbance. These processes contribute to the development of structurally diverse habitats, which are recognised as important for ecological resilience and the support of a wide range of species.
5. Observational Evidence and Spatial Patterns
Long-term field observation, supported by aerial imagery, provides a clear view of how grazing activity is expressed spatially across the landscape. On Dartmoor, these patterns are not uniformly distributed, but instead form a complex arrangement of interconnected features that reflect the movement and behaviour of ponies over time.
At ground level, variation in vegetation structure is evident through differences in height, density, and composition within relatively small areas. Closely grazed patches are frequently located adjacent to taller stands of vegetation, with transitional zones between them. These variations do not occur randomly, but appear to correspond with areas of repeated use by ponies.
Aerial observations of Bellever reveal these patterns more clearly.
From above, areas of dense molinia grass are intersected by a network of narrow pathways, forming visible routes across the landscape.
These pathways vary in width and definition, with some appearing as well-established tracks and others as lighter, less frequently used lines. Together, they form an interconnected system linking different parts of the site. These pathways align with areas where vegetation height is reduced and ground conditions differ from the surrounding sward. In some locations, trampling has resulted in the exposure of small areas of bare ground, while in others the vegetation appears compressed or more closely grazed.
These features contribute to increased structural variation within what might otherwise appear as a continuous vegetation cover.
At Bellever, these visual patterns correspond with measured ecological change. Areas influenced by pony movement and grazing have been shown to support significantly higher levels of heather regeneration, consistent with measured increases in seedling establishment, alongside reductions in Molinia dominance and increased areas of exposed ground (Lunt et al., 2021). These findings align with the spatial patterns visible in aerial imagery, where pathways and disturbed areas coincide with zones of emerging vegetation change.
Repeated observation indicates that these spatial patterns are persistent over time. Ponies have been observed to follow consistent routes across the moor, returning to the same areas and reinforcing existing pathways. This repeated use contributes to the development of stable movement corridors within the landscape.
The distribution of these features is influenced by a range of factors, including topography, vegetation type, and access to resources such as water and shelter. As a result, the patterns observed reflect both environmental conditions and the behaviour of the animals interacting with them. Detailed site studies have shown that this variation occurs at fine spatial scales, with differences in vegetation height, composition, and ground exposure observable within relatively small areas, reflecting the localised impact of pony movement and grazing (Richards, 2020; Westwood, 2023). These structural differences have also been shown to influence associated fauna, with variation in vegetation height and ground conditions supporting differing invertebrate communities across the site (Walsh, 2024).
From a landscape perspective, these observations indicate that grazing activity is expressed not only through the removal of vegetation, but through the creation of spatial structure. The combination of grazing, movement, and disturbance results in a mosaic of vegetation states, comprising closely grazed areas, taller vegetation, transitional zones, and exposed ground.
This mosaic is a defining characteristic of the grazed landscape at Bellever. It is not imposed through external intervention, but develops gradually through the interaction between ponies and their environment. The resulting structure provides a range of conditions that may support different plant and animal species, reflecting the importance of spatial variation within ecological systems.
6. Ecological Mechanisms and Interpretation
The spatial patterns observed within the landscape can be understood through established ecological mechanisms associated with grazing, disturbance, and vegetation dynamics.
These processes operate at multiple scales and contribute to the development and maintenance of structurally diverse habitats.
Selective grazing is a key mechanism influencing vegetation structure. By utilising certain plant species and areas more intensively than others, herbivores create variation in sward height and composition. This selective use contributes to the formation of a patchwork of vegetation states, rather than a uniform sward. This variation is widely recognised as an important factor in supporting biodiversity, with both modern and palaeoecological studies indicating that large herbivores contribute to the development of structurally diverse vegetation (Sandom et al., 2014), as it provides a range of microhabitats and resources within a single landscape.
Disturbance associated with movement, including trampling, also plays a significant role. The physical impact of hooves can disrupt dense vegetation, compress plant material, and expose areas of bare ground. These disturbed areas alter local conditions at the soil surface, including light availability and seed to soil contact, which can influence patterns of plant establishment and regeneration. This increase in exposed ground has been identified as a key factor in enabling heather regeneration, providing suitable conditions for seed germination and establishment (Leigh, 2018; Richards, 2020).
Research conducted at Bellever has demonstrated that areas of disturbed ground are associated with the establishment of Calluna vulgaris, with studies at Bellever recording a 31-fold increase in heather seedlings in grazed areas compared to ungrazed controls (Lunt et al., 2021), indicating a link between grazing activity and heathland regeneration. This relationship highlights the importance of disturbance as a process within upland systems, particularly where dominant species such as Molinia caerulea limit opportunities for other plants to establish.
Around former salt lick sites, repeated pony activity breaks the molinia canopy — exposing bare ground where new life can take hold.
What begins as a small point of pressure expands outward — shaping the surrounding vegetation over time.
In addition to influencing vegetation structure, grazing activity contributes to nutrient cycling and redistribution. The movement of herbivores across the landscape, combined with the deposition of dung and urine, results in the transfer of nutrients between areas.
This process can create localised variation in soil fertility, further contributing to spatial heterogeneity.
The combined effects of selective grazing, disturbance, and nutrient redistribution operate over time to shape vegetation patterns and habitat structure. These processes are dynamic and interact with environmental factors such as soil type, hydrology, and climate, resulting in variation across the landscape. These changes extend beyond vegetation, with evidence indicating that grazing-driven variation in habitat structure influences both the abundance and diversity of ground-dwelling invertebrates (Walsh, 2024).
Within this framework, the patterns observed at Bellever, including the development of pathways, variation in vegetation height, and the presence of exposed ground, are consistent with recognised ecological processes associated with grazing systems. Rather than representing isolated features, these patterns reflect the interaction between herbivore behaviour and environmental conditions.
Understanding these mechanisms provides context for interpreting the role of equids within conservation landscapes. Their behaviour contributes to processes that influence vegetation structure and habitat diversity, supporting the development of heterogeneous systems that are widely associated with ecological resilience and biodiversity.
7. Supporting Evidence from Other Studies
The patterns observed on Dartmoor are consistent with findings from a wider body of research examining the role of large herbivores, including equids, in shaping vegetation structure and ecological processes.
Studies across a range of upland and semi-natural systems have demonstrated that grazing contributes to the development of heterogeneous vegetation structures. Variation in grazing intensity, combined with selective feeding behaviour, has been shown to produce a mosaic of closely grazed areas, taller vegetation, and transitional zones. This structural diversity is widely associated with increased habitat complexity and the support of a broader range of plant and animal species (Bullock & Pakeman, 1996).
Research focusing specifically on equids indicates that their behavioural and physiological characteristics influence how these patterns develop. As hindgut fermenters, equids are capable of processing large quantities of fibrous vegetation (Menard et al., 2002), allowing them to utilise plant species that may be less accessible to more selective grazers. This capacity contributes to their role in interacting with dominant vegetation types, including coarse grasses.
A study of semi-wild horse grazing in the Côa Valley, Portugal, found that grazing by horses contributed to the regulation of grass height and the maintenance of open habitats, while also influencing plant community composition (Ribeiro et al., 2025). The study reported that grazed areas exhibited differences in vegetation structure compared to ungrazed controls, including reduced grass height and changes in the relative abundance of plant functional groups.
The same study identified an increase in flowering plant species, contributing to greater habitat diversity, with potential benefits for plant and insect communities. In addition, higher levels of species turnover were recorded in ungrazed areas, suggesting that grazing may contribute to the stability of plant communities over time.
Other studies of grazing systems have similarly highlighted the role of disturbance and spatial variation in supporting ecological processes. Grazing has been shown to influence plant species richness, reduce the dominance of competitive vegetation, and create conditions that support regeneration and habitat diversity. These findings are consistent across a range of ecosystems, including heathlands, grasslands, and rewilding landscapes.
It is also recognised that the effects of grazing are influenced by factors such as grazing intensity, environmental conditions, and the characteristics of the herbivores involved.
Lower intensity or extensive grazing systems, including those involving free-ranging animals, have been associated with the maintenance of structural variation without the uniform reduction of vegetation height.
Taken together, these studies provide a broader context for the observations recorded on Dartmoor. More recent work has also begun to explore the role of ponies within wider management systems, where their grazing interacts with other processes to influence vegetation structure, nutrient cycling, and longer-term habitat dynamics (Guerrero, N. (2024). Patterns of selective grazing, movement, disturbance, and resulting vegetation structure are consistent with established ecological principles and documented outcomes in other systems.
8. Synthesis and Implications
The observations recorded on Dartmoor, when considered alongside established ecological research, indicate that native ponies contribute to a range of processes that influence vegetation structure and habitat condition within upland landscapes.
At Bellever, these processes, observed within a long-term conservation grazing study, are supported by measured outcomes, including substantial increases in heather regeneration, with significant increases in seedling establishment, reductions in Molinia cover, and improved condition of mature heathland vegetation under pony grazing (Lunt et al., 2021).
These findings are supported by a sequence of site-based studies demonstrating consistent patterns of vegetation change, grazing behaviour, and habitat response over time (Leigh, 2018; Richards, 2020; Westwood, 2023; Walsh, 2024).
Field observations demonstrate consistent patterns of selective grazing, repeated movement, and localised disturbance. These behaviours are visible across the landscape through the development of pathways, variation in vegetation height, and the presence of exposed ground. Aerial imagery further illustrates how these features form interconnected patterns across the landscape, contributing to a mosaic of vegetation states.
Ecological research provides a framework for understanding these patterns. Selective grazing is associated with the development of structural heterogeneity, while disturbance processes, including trampling, create conditions that support plant establishment and regeneration. Nutrient redistribution through animal movement further contributes to spatial variation in soil conditions and vegetation composition.
The consistency between field observations and published studies suggests that the behaviour of equids contributes to processes that are widely recognised as important in conservation landscapes. These include the regulation of vegetation structure, the creation of habitat variation, and the maintenance of conditions that support a range of plant and animal species.
Within this context, equids can be understood as influencing landscape structure not only through the consumption of vegetation, but through the interaction of grazing, movement, and disturbance over time. These processes operate cumulatively, resulting in patterns that develop gradually rather than through immediate or uniform change.
The findings presented in this study do not seek to evaluate alternative grazing systems or management approaches. Instead, they provide an account of how native ponies interact with the landscape and how these interactions align with recognised ecological mechanisms.
Understanding this role has implications for how conservation landscapes are interpreted and managed. The presence of equids may contribute to the development of structurally diverse habitats, which are associated with ecological resilience and biodiversity. Recognising these processes provides an opportunity to consider how existing grazing systems function within the landscape and how they may support long-term ecological outcomes.
This field study contributes to a growing body of evidence indicating that large herbivores play an integral role in shaping semi-natural systems. In the case of Dartmoor, long-term field observation suggests that native ponies form part of these processes, influencing the structure and ongoing development of the landscape through their continued presence and behaviour.
9. The outcome: A living mosaic
Across Dartmoor, ponies move through a landscape no longer dominated by molinia, but reshaped into a mosaic of heather, grass, and open ground.
This pattern is not confined to a single patch, it spreads across the moor as herds move, graze, and return.
Through grazing, browsing, and trampling, ponies create the conditions for regeneration, one bite, one step at a time.
References, Supporting Research and Further Reading
Abdalla, M., Hastings, A., Chadwick, D.R., Jones, D.L., Evans, C.D., Jones, M.B., Rees, R.M. and Smith, P. (2018) ‘Critical review of the impacts of grazing intensity on soil organic carbon storage and other soil quality indicators in extensively managed grasslands’, Agriculture, Ecosystems & Environment, 253, pp. 62–81.
Bullock, J.M. and Pakeman, R.J. (1996) ‘Grazing of lowland heath in England: management methods and their effects on heathland vegetation’, Biological Conservation, 79, pp. 1–13.
Celaya, R., Ferreira, L.M.M., García, U., Rosa García, R. and Osoro, K. (2011) ‘Diet selection and performance of cattle and horses grazing in heathlands’, Animal, 5(9), pp. 1467–1473.
Colston, A. (2021) Stakeholder narratives of Dartmoor’s Commons: tradition and the search for consensus in a time of change. PhD thesis. University of Exeter.
Ferreira, L.M.M., Celaya, R., Benavides, R., Jáuregui, B.M., García, U., Santos, A.S., Rosa García, R., Rodrigues, M.A.M. and Osoro, K. (2013) ‘Foraging behaviour of domestic herbivore species grazing on heathlands associated with improved pasture areas’, Livestock Science, 155, pp. 373–383.
Fraser, M.D., Stanley, C.R. and Hegarty, M.J. (2019) ‘Recognising the potential role of native ponies in conservation management’, Biological Conservation, 235, pp. 112–118.
Fraser, M.D., Theobald, V.J., Dhanoa, M.S. and Davies, O.D. (2011) ‘Impact on sward composition and stock performance of grazing Molinia-dominant grassland’, Agriculture, Ecosystems & Environment, 144, pp. 102–106.
González-Hernández, M.P., Mouronte, V., Romero, R., Rigueiro-Rodríguez, A. and Mosquera-
Losada, M.R. (2020) ‘Plant diversity and botanical composition in an Atlantic heather-gorse dominated understory after horse grazing suspension: comparison of continuous and rotational management’, Global Ecology and Conservation, 23, e01134.
Guerrero, N. (2024) Integrated land management: gorse control through flailing and Dartmoor pony grazing. MSc dissertation. Plymouth University.
Leigh, J. (2018) Conservation grazing with Dartmoor ponies: reducing Molinia dominance and encouraging the germination of Calluna vulgaris on an upland site in Dartmoor. MSc dissertation. Plymouth University.
López López, C., Ferreira, L.M.M., García, U., Moreno-Gonzalo, J., Rodrigues, M.A.M., Osoro, K., Ferre, I. and Celaya, R. (2017) ‘Diet selection and performance of horses grazing on different heathland types’, Animal, 11(10), pp. 1708–1717.
Lunt, P. et al. (2021) ‘Using Dartmoor ponies in conservation grazing to reduce Molinia caerulea dominance and encourage germination of Calluna vulgaris in heathland vegetation on Dartmoor, UK’, Conservation Evidence Journal.
Ménard, C., Duncan, P., Fleurance, G., Georges, J.-Y. and Lila, M. (2002) ‘Comparative foraging and nutrition of horses and cattle in European wetlands’, Journal of Applied Ecology, 39, pp. 120–133.
Rare Breeds Survival Trust (2020) Equines in conservation grazing. Technical report.
Richards, S. (2020) The use of Dartmoor ponies for conservation grazing: reducing dominance of Molinia caerulea and encouraging the germination of Calluna vulgaris. MSc dissertation. Plymouth University.
Ribeiro, I., Aliácar, S., Domingos, T., McCracken, D. and Proença, V. (2025)‘Semi-wild horse grazing as a rewilding strategy: assessing effects on vegetation structure and composition in the Côa Valley, Portugal’, Frontiers in Ecology and Evolution, 13, 1596560.
Walsh, R.J. (2024) Dartmoor nature conservation: evaluating changes in ground invertebrates associated with vegetation change. MSc dissertation. Plymouth University.
Westwood, J. (2023) Revisiting conservation grazing with Dartmoor ponies: reducing purple moor grass (Molinia caerulea) dominance and encouraging the germination of Calluna vulgaris on an upland site in Dartmoor. MSc dissertation. Plymouth University.
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