Small Natural Features Research Articles

From the bottom up – attributes of small vesper bats’ activity sites in an upland ecosystem in Chiapas, México

We studied bats in a natural protected area and the influence zone in Chiapas, México. Focusing on small vesper bats (Vespertilionidae: Myotinae) in water sinkholes, flooded surfaces, and forested locations (sampling sites), our objectives were to: 1) differentiate the sampling sites based on abiotic and biotic variables, 2) compare the relative activity between the contrasting sampling sites, and 3) determine the relative importance of surrounding land covers amounts on the relative activity. We expected the following: 1) that sampling sites would be differentiable based on an interaction of environmental conditions and nocturnal flying insects’ biomass, 2) to find a significantly higher relative activity associated with water bodies as a reflection of potential drinking and feeding supplies, and 3) that forest cover would have a significant association in a positive direction with the relative activity as a reflection of roosting and commuting opportunities. We obtained weather data with a portable station, collected flying nocturnal insects with a passive trap, and recorded bats with ultrasonic detectors. We also used satellite imagery to calculate land covers amounts around the sampling sites. We performed a multivariate analysis to compare sampling sites, and elaborated correlation models of relative activity against surrounding land covers amounts. The only significant variable for differentiating sampling sites was wind speed; in water sinkholes, with lower mean value compared to flooded surfaces and forested locations, along with a comparatively higher percentage of dipterans in the samples. The mean relative activity of bats was significantly higher in water sinkholes, with maximum values reaching 95 %, which we can relate to environmental conditions and resources available. We found associations in a positive direction with forest cover, secondary forest and water surface, and negative with agricultural land and human development. Finally, we argue that some of the water sinkholes meet the criteria of small natural features supported by the unusual activity of the studied bats, and that targeted conservation actions will complement other strategies implemented in the area.

Environmental heterogeneity increases the conservation value of small natural features in karst landscapes

Local biodiversity hotspots are often located within regions where extreme and variable environmental – e.g., climatic and soil – conditions occur. These areas are conservation priorities. Although environmental heterogeneity is recognised as an important determinant of biodiversity, studies focusing on the effects of multiple environmental heterogeneity components in the same ecosystem are scarce. Here we investigate how topography and related microclimatic variables and soil properties may influence the biodiversity and conservation value of karst landscapes. Karst landscapes of the world contain millions of dolines (i.e. bowl- or funnel-shaped depressions) that may function as ‘small natural features’ with a disproportionately large role in maintaining biodiversity relative to their size. We assessed the diversity of microclimates, soils and vegetation and their relationships in six microhabitats (south-facing slopes, east-facing slopes, west-facing slopes, north-facing slopes and bottoms of dolines, and the adjacent plateau) for nine large dolines in a grassland ecosystem. Although there were remarkable differences among the conservation value of these microhabitats (e.g., representation of different species groups, presence of ‘climate relicts’), each microhabitat had an important role in maintaining species that are rare or absent in other microhabitats in the landscape. We found that the studied dolines exhibited highly variable environmental conditions and promoted a high diversity of vegetation types with unique species composition, contributing to the topographic, climatic, soil, vegetation and land cover heterogeneity of karst landscapes. Therefore, our findings highlight that dolines may function as local biodiversity hotspots and have a crucial conservation importance. As dolines are widespread topographic features in many karst landscapes throughout the world, our results could be directly applied to other regions as well. An integrated approach is urgently needed to provide guidelines for landscape management, promoting the retention of the microhabitat diversity of small natural features for species vulnerable to climate change and/or various disturbances.

Between a rock and a large place: the importance of multi-scale geomorphological features to seabird nest site selection.

The importance of habitats to animal, and, in particular, bird conservation, has long been recognized (Martin et al. 2007, Yorio 2009, Oppel et al. 2018). From the study of habitat has emerged the importance of geodiversity (Hjort et al. 2015, Hunter et al. 2017, Malcolm and Hunter 2017). The relationship between geodiversity and biodiversity is a fundamental, yet often-overlooked aspect of ecology; for example, we recently demonstrated that several seabird species show preferences for particular small natural features of potential nest sites (Eveillard-Buchoux et al. 2019 and Fig. 1).

The importance of small natural features in forests-How the overgrowth of forest gaps affects indigenous flower supply and flower-visiting insects and seed sets of six Campanula species.

The abandonment of historical land‐use forms within forests, such as grazing or coppicing, and atmospheric nitrogen deposition, has led to an increasing overgrowth of forest gaps and canopy closure in forest ecosystems of Central Europe. From 1945 to 2015, 81% of the forest gaps greater than 150 m2 within the study area transitioned into a closed forest.This study investigated how the overgrowth process affects flower supply, flower visitors, and reproduction of Campanula species. Six native Campanula species with different light requirements were used as phytometers.The forest gaps in the studied area are a feature of the historical European cultural landscape. We compared large gaps caused by human activities, small gaps caused by habitat conditions, and closed forests. In eight blocked replicates, each with the three habitat categories, we recorded the flower cover and number of indigenous flowering species in the immediate surroundings, and, of six Campanula species, flower visitors and seed production.Forest gaps and their size positively affected the number of flowering plant species in the surrounding area, the number of all flower visitor groups, and the number of seeds produced by all six Campanula species. Flower cover in the surrounding area was higher in large gaps, but there was no difference between small gaps and closed forests. Among flower visitors, small bees varied the most between the three habitat categories, and flies varied the least. The effect on the number of seeds produced was particularly strong for three light‐demanding Campanula species.The overgrowth of forest gaps negatively affected flower supply, flower‐visiting insects, and seed sets of six Campanula species. Forest gaps should be managed to maintain the reproduction of open forest plants and their pollinators.

Linking environmental heterogeneity and plant diversity: The ecological role of small natural features in homogeneous landscapes

Small natural features (SNFs), such as road verges, midfield islets, rocky outcrops and ancient burial mounds, provide safe havens for species of natural habitats in human-modified landscapes; therefore, their great ecological importance is in contrast to their small size. SNFs often have a high topographical heterogeneity and abiotic conditions, which differ from their surroundings; therefore, they provide a unique opportunity for establishing links between environmental heterogeneity (EH) and biodiversity. However, no study has so far investigated the EH components of topographically heterogeneous SNFs in a comprehensive framework, by linking environmental and biotic parameters. To fill this knowledge gap, we evaluated the EH components and their effect on biodiversity on ancient mounds covered by semi-natural grasslands in the Pannonian (Hungary) and Continental (Bulgaria) biogeographical regions. We designated 16 study sites, each containing a few-metre-high mounds with five microsites (top, north-, east-, south- and west-facing slopes) and a nearby plain grassland. At each microsite, we measured soil moisture, soil chemical properties, solar radiation and microclimate; and recorded the cover of vascular plants in a total of 480 plots. On the mounds, topographical heterogeneity was associated with sharp differences in microclimate and soil properties. Besides the contrast between mild north-facing and harsh south-facing slopes, east- and west-facing slopes also sustained unique microsites characterised by dynamic diurnal changes in air temperature and vapour pressure deficit. Various combinations of the EH components resulted in unique plant species compositions within the microsites, and supported the co-occurrence of species typical of contrasting habitat types, even within a couple of metres. By combining high-resolution measurements of abiotic factors with fine-scale vegetation sampling, our study provides evidence that widespread SNFs with complex topography harbour several grassland-specialist plant species and introduce a high level of EH to otherwise homogeneous plain landscapes, which cover one third of the global land area.

Habitat islands outside nature reserves – Threatened biodiversity hotspots of grassland specialist plant and arthropod species

In transformed landscapes, many populations of grassland specialist plant and animal species live outside the few protected areas and are often preserved on 'small natural features' (SNFs) such as road verges, field margins and rocky outcrops. In the steppe and forest steppe zones of Eurasia ancient burial mounds (kurgans) are widespread SNFs providing refuge for grassland species. Based on a large-scale botanical and zoological survey of 138 kurgans in Hungary, we compared the management regimes, the presence of threatening factors and the conservation potential of kurgans embedded in non-protected transformed landscapes and in protected areas. We found that kurgans extend the borders of the protected areas by maintaining populations of grassland specialist plants and arthropods (ants, orthopterans, true bugs and rove beetles) even in transformed landscapes. We revealed that the lack of proper management, the presence of anthropogenic disturbances and encroachment of woody species are the most considerable threats to the long-term maintenance of biodiversity on kurgans located outside the protected areas. For their effective conservation a new approach is needed, which can cope with the small area and dispersed localities of the kurgans and can integrate them into the network of other SNFs on a landscape-level. As the ecological importance of kurgans is disproportionate to their size conservation actions focusing on their protection offers a greater rate of return of the efforts than can be expected in case of larger continuous sites.

Small-scale natural landscape features and seabird nesting sites: the importance of geodiversity for conservation

Landscape geodiversity, and in particular small natural features (SNF), are crucial components of habitat suitability for many threatened species. Rocky cliffs at the sea-continent interface present complex small-scale geomorphologies which are exploited by nesting seabirds. Elucidation of the relation between nest-site geomorphology and species preference in cliff-nesting seabirds. Evaluation of the potential of cliff-face SNF as seabird conservation tools. Nest site geomorphological characteristics of four Atlantic (Brittany, France) cliff-dwelling seabirds (Razorbill, Guillemot, Fulmar, and Kittiwake) were categorized, and scored for degree of enclosure. Of the 1048 nest sites examined, the greatest species overlap in location was the mid-region of the cliff face: Fulmar was concentrated in the upper half of the cliff, while Kittiwake showed the most extended vertical distribution. A distinct trend was evident with respect to ceiling presence and size: Razorbill + Kittiwake > Guillemot > Fulmar. Clear trends were also evident in ceiling inclination, ledge size, and side wall presence and inclination. A distinct ‘degree of enclosure’ hierarchy was documented, consolidated with the addition of sympatric species known for their extreme preferences: Atlantic Gannets and Guillemots at the extreme ‘open’ end, and Puffins and Storm Petrels at the extreme ‘closed’ end. Some plasticity in site choice was observed, probably corresponding to sub-optimal default choices. Despite some plasticity, both vertical level and enclosure characteristics are associated with particular seabird species. Given the importance of nesting sites to seabird reproduction, the identification and conservation of these SNF constitute crucial conservation objectives.

Rocky outcrops conserve genetic diversity and promote regeneration of a threatened relict tree in a critically endangered ecosystem

The loss of individuals in disturbed sites may be buffered by the presence of small natural features (SNFs), sites acting as ecological refuges preventing the loss of phenotypic variability and genetic diversity of plants. An important group of SNFs is rocky outcrops, singular geological formations that stand out from the surrounding matrix which could host a greater species diversity. We tested the value of rocky outcrops as SNFs of a Tertiary relict tree, the Chilean lucuma Pouteria splendens (Sapotaceae). We identified vegetation patches with P. splendens and characterized their landscape properties in sites associated with rocky outcrops and clearings (plains). Then, we contrasted the genetic diversity, phenotypic variability and sapling abundance of P. splendens inhabiting rocky outcrops and plains. We observed that rocky outcrops sustained subtle higher genetic diversity compared with plains, but non-significant genetic structuration was detected between habitat types. Independently of the habitat type, P. splendens have a significant role in the sapling recruitment: their number was higher underneath of conspecifics than in open spaces. Besides, plants in the rocky outcrops produced smaller and ovoid-shaped fruits, as a possible result of selective pressures generated by frugivorous. We propose that rocky outcrops are regeneration sites for P. splendens. However, subtle differences in genetic diversity between habitats and the lacking of genetic structuration suggest that conservation strategies should be focused on the protection of all habitat types as a manner of maintaining ecosystem processes in this singular vegetation remnant.

Conservation relevance of bat caves for biodiversity and ecosystem services

All ecosystems are dotted by salient small natural features that not only characterize them but also significantly add to their biodiversity and functions. These small natural features are prominent but easily missed when ecosystems are described. Caves are one key example of this. Cave ecosystems are underrepresented in conservation planning and implementation around the world and have become mostly overlooked in conservation strategies overall. Caves contain high levels of biodiversity from fungi to invertebrates to vertebrates. This paper emphasizes bat caves as providers of ecosystem services to vast areas surrounding them, in the order of hundreds of thousands of square km just in North America. Their influence extends three-dimensionally via subterraneous water bodies and via the aerial nightly dispersal of the bats that provide a host of services from seed dispersal to pollination to pest control. The examples used focus primarily on free-tailed bats in North America, but the same principles apply to any other cave in the world with significant bat colonies. Caves enjoy protection, legal or actual, in some countries and not in others, and as a result many have suffered damage or been destroyed altogether. Common threats are vandalism, urbanization, and pollution. Many caves are attractive as ecotourism destinations and provide unique opportunities to educate the public about unexpected biodiversity values and ecosystem services. Inventorying caves poses challenges, but efforts are under way to assess caves in need of protection. Incipient cave protection strategies include legal and educational efforts, and management. Although illustrated with bat caves, given the importance of all caves and their precarious status, it is time to call the attention of decision makers about the urgent need to launch a worldwide cave conservation initiative.

Managing small natural features: A synthesis of economic issues and emergent opportunities

Small natural features (SNFs), landscape elements that influence species persistence and ecological functioning on a much larger scale than one would expect from their size, can also offer a greater rate of return on conservation investment compared to that of larger natural features or more broad-based conservation. However, their size and perceived lack of significance also makes them more vulnerable to threats and destruction. We examine the management of SNFs and conservation of the associated ecosystem services they generate from an economics perspective. Using the economic concept of market failure, we identify three key themes that explain prevailing threats to SNFs and characterize impediments to and opportunities for SNF management: (1) the degree to which benefits derived from the feature spillover, beyond the feature itself (spatially and temporally); (2) the availability and quality of information about the feature and those who most directly influence its management; and (3) the existence and enforcement of property rights and legal standing of the feature. We argue that the efficacy of alternative SNF management approaches is highly case dependent and relies on four key components: (1) the specific ecosystem services of interest; (2) the amount of redundancy of the SNF on the landscape and the level of connectivity required by the SNF in order to provide ecosystem services; (3) the particular market failures that need correcting and their scope and extent; and (4) the magnitude and distribution of management costs.

Small natural features with large ecological roles in ancient agricultural landscapes of Central Europe - history, value, status, and conservation

Throughout history traditional land uses have created small natural features (SNFs) that can serve as biodiversity hotspots or remnants in agricultural landscapes that may otherwise support little biodiversity. SNFs in these landscapes include field and pasture margins, forest fringes, hedges, hollow ways (sunken lanes), stone walls, sand and gravel pits, and quarries. Many of these SNFs were established thousands of years ago as humans began to establish agricultural practices in Europe and other parts of the world. In some cases, these SNFs are old enough to have allowed unique ecological communities to develop or even new species to evolve. The consolidation of lands and intensification of agriculture and mining practices, however, have eradicated many of these SNFs; this decline started in the 19th century and has accelerated in recent years. Conservation practices that aim to maintain these anthropogenic SNFs are increasing, largely due to the growing recognition of their conservation value. New government initiatives, agro-environmental schemes, and greenways and ecosystem networks are being implemented with some success. These efforts, however, are far from perfect; much more work on management, restoration, and re-creation of anthropogenic SNFs is required to ensure that they persist and continue to support biodiversity in highly modified landscapes.

Springs: Conserving perennial water is critical in arid landscapes

Arid landscapes are highly water-limited environments and all water (surface and groundwater) is environmentally, culturally and economically important. Springs, sites where groundwater discharges at the Earth's surface, are often the only perennial aquatic environments in arid regions. By providing habitats for aquatic biota, as well being an essential water resource for terrestrial species and human settlements, they are small natural features that make a contribution to ecological processes and biodiversity that extends far beyond their area. Many contain endemic, rare or relictual species of plants, fishes and invertebrates and are recognized as globally important biodiversity hotspots and evolutionary and ecological refugia. However, water resource development and invasive species are major threats to these systems. Future climate scenarios indicate that extended droughts may become more common in some arid regions. Such droughts will increase the pressure to extract groundwater for human uses. Increasing aquifer drawdown will result in the loss of some spring habitats and the endemic and dispersal-limited species they support. Conservation challenges include addressing the additive impacts of water extraction and exotic and invasive species and managing recreational activities. Although the isolation and small size of arid land springs makes them extremely vulnerable to anthropogenic impacts, it also means that protection and management may be more feasible and cost effective than for larger aquatic ecosystems. However, multiple approaches and ongoing actions will be required to address additive impacts. Examples of current conservation measures include fencing to exclude feral herbivores, removal of alien aquatic species and assisted re-colonisation of dispersal-limited, endemic species. The fundamental conservation priority is the protection of the groundwater resource (aquifers) on which arid land springs depend.

Challenges for the conservation of marine small natural features

Seascapes contain a mosaic of ecosystem types, including ‘small natural features’ that support a diverse fauna and flora, and provide ecosystem services disproportionate to their size. These include tropical coral reefs, seagrass meadows, rhodolith beds, kelp and mangrove forests as well as deep-sea coral reefs, sponge gardens and hydrothermal vents. The contributions of coral reefs, mangrove forests and seagrass meadows are well recognised as important components of tropical marine seascapes. In temperate regions, hotspots of primary productivity such as kelp forests, and vegetation-based ecosystems found at coastal margins play significant roles in nutrient and sediment trapping and coastal protection. Biogenic features in coastal regions can also play important roles, including shellfish reefs, sponge gardens and macroalgal mats that provide physical structure within soft sediment ecosystems. Similar biogenic features are found in the deep sea, which often occur associated with seamounts, canyon features, cold seeps and hydrothermal vents. Many marine small natural features are globally threatened as they are found at the interface with human-influenced landscapes (coastal ecosystems) or are the focus of resource exploitation (e.g., trawling for fish associated with seamounts and canyons). Challenges in management are, however, consistent across depths, and highlight the restricted spatial extent of such features, and the limited information typically available on their distributions, and the ecosystem services they provide. Numerous strategies can be utilized to sustainably manage, protect, create and restore these marine small natural features and their associated biodiversity.

Conserving small natural features with large ecological roles: A synthetic overview

Small Natural Features (SNFs) are analogous to keystone species in that they have ecological importance that is disproportionate to their size. Thus the recognition and management of SNFs can be an efficient way to conserve biodiversity and ecosystem services. In particular, while the size of SNFs can engender threats (e.g., they are often overlooked and are relatively vulnerable to complete destruction), small size also leads to special conservation opportunities (e.g., integration with resource uses such as forestry or fisheries). Commonly, SNF conservation begins with education and inventory to form a foundation for appropriate, targeted protection and/or sustainable management. However, in cases of severe degradation or loss, more intensive activities such as restoration or creation may be required. Diverse approaches to conservation action are possible. For example, sometimes SNF conservation is undertaken incidentally to other efforts or on a voluntary basis; sometimes it involves substantial economic incentives or restrictive regulations. In general, the required investment for SNF conservation is likely to be smaller than that for larger areas, with disproportionate benefits given the substantial spatio-temporal influence of these features. In practice, conservation of SNFs should be complementary to traditional, larger-scale, forms of conservation by fostering creative, constructive efforts to conserve some seemingly minor features; features that have previously unknown or unappreciated roles critical to their broader ecosystems and to biodiversity.

Conserving small natural features with large ecological roles: An introduction and definition

Conserving small natural features with large ecological roles: An introduction and definition

Rocky outcrops: A hard road in the conservation of critical habitats

Rocky outcrops are geological features that encompass a wide variety of physical environments, including escarpments, overhangs, cliffs, tors, boulder-heaps and insular domes (inselbergs). They support high levels of species diversity and endemism, and provide stable micro-climates for thousands of years. They provide critical breeding sites for many top order mammalian and avian predators; nesting sites for colonial species such as seabirds, bats and swifts and ecological refuges for ancient lineages. Rock overhangs and caves also provide important insights into our ecological past where they contain the remains of extinct species. Because rocky environments are generally less fertile, steep-sided and less accessible than the surrounding landscape, they are typically less prone to human disturbances. Nonetheless, many rocky outcrops, particularly in commodity production landscapes, face a variety of threats including soil compaction and erosion caused by livestock; nutrient enrichment and weed invasion; introduced predators; and physical damage caused by recreational and quarrying activities. Even rocky outcrops in seemingly pristine environments may be affected by altered fire regimes, air pollution (including acid rain) and potentially climate change. In agricultural landscapes, various approaches have been taken to conserve rocky outcrops, including land acquisition for conservation, fencing from livestock and private land conservation agreements with landholders. In more intact landscapes, targeted actions to conserve rock-dwelling fauna include limiting human access to critical breeding sites, baiting to reduce pressure from introduced predators, restoring rock microhabitat and translocation of endangered species. Future management actions will need to involve better inventory of the biophysical attributes and fine-scale mapping to improve the awareness of these small natural features.

Conserving large old trees as small natural features

In many ecosystems globally, large old trees occur as single, spatially isolated individual trees or as small groups of scattered trees and can therefore be considered to be small natural features. Despite being constrained spatially, individual large old trees and small stands of such trees nevertheless play numerous critical ecological roles (e.g. in carbon storage and provision of wildlife habitat). The protection and management of large old trees as small natural features is essential to maintain these roles and will often require targeted fine-scale conservation strategies. Such strategies can include bans on cutting trees above a certain size, micro-fencing to control threats associated with livestock grazing, and buffers comprised of other vegetation to limit the impacts of fire and chemical sprays. Effective conservation to mitigate the effects of factors threatening large old trees will often demand ecosystem-specific responses. This is because the drivers of loss will often manifest in ecosystem-specific ways. Three general principles will likely apply in almost all cases: (1) Protect existing individual large old trees; (2) Reduce rates of adult mortality. This is because adult mortality is a key part of the life cycle of large old trees; increased adult mortality can lead to population crashes; and (3) Ensure there are sufficient recruits of trees of varying ages to replace existing large old trees as they eventually die.

Integrative conservation of riparian zones

Riparian zones are the interface between aquatic and terrestrial systems along inland watercourses. They have a disproportionate ecological role in the landscape considering their narrow extent, which makes them a good example of small natural features (sensu Hunter, 2017-inthisissue). Characteristically, riparian zones increase species richness in the landscape and provide key services to society, such as soil fertility, water purification, and recreation. Despite the recognized importance of riparian zones for ecological, economic and social reasons, and the vast amount of scientific literature exploring measures for their conservation, current management is still failing at enabling a proper ecological functioning of these areas. The best practices for conservation of riparian zones have mostly focused on manipulating biotic and physical components (e.g. renaturalizing flow regimes, improving channel mobility, and controlling invasions of exotic ecosystem engineer species). However, these strategies face important technical, socio-economic, and legal constraints that require a more integrative approach for effective conservation. In this paper we summarize the main problems affecting riparian zones and their current management challenges. Following Hunter et al. (2017-inthisissue), we review novel approaches to conservation of riparian zones, complementary to manipulating processes that reflect contemporary management and policy. These include (1) investing in environmental education for both local people and technical staff, (2) guaranteeing qualitative and long term inventories and monitoring, (3) establishing legislation and solutions to protect riparian zones, (4) framing economic activities in riparian zones under sustainable management, and (5) planning restoration of riparian zones at multiple and hierarchical spatio-temporal scales.

Improving management of small natural features on private lands by negotiating the science-policy boundary for Maine vernal pools.

Vernal pools are far more important for providing ecosystem services than one would predict based on their small size. However, prevailing resource-management strategies are not effectively conserving pools and other small natural features on private lands. Solutions are complicated by tensions between private property and societal rights, uncertainties over resource location and function, diverse stakeholders, and fragmented regulatory authority. The development and testing of new conservation approaches that link scientific knowledge, stakeholder decision-making, and conservation outcomes are important responses to this conservation dilemma. Drawing from a 15-y history of vernal pool conservation efforts in Maine, we describe the coevolution of pool conservation and research approaches, focusing on how research-based knowledge was produced and used in support of management decisions. As management shifted from reactive, top-down approaches to proactive and flexible approaches, research shifted from an ecology-focused program to an interdisciplinary program based on social-ecological systems. The most effective strategies for linking scientific knowledge with action changed as the decision-makers, knowledge needs, and context for vernal pool management advanced. Interactions among stakeholders increased the extent to which knowledge was coproduced and shifted the objective of stakeholder engagement from outreach to research collaboration and development of innovative conservation approaches. New conservation strategies were possible because of the flexible, solutions-oriented collaborations and trust between scientists and decision-makers (fostered over 15 y) and interdisciplinary, engaged research. Solutions to the dilemma of conserving small natural features on private lands, and analogous sustainability science challenges, will benefit from repeated negotiations of the science-policy boundary.

Large-scale classification of water areas using airborne topographic lidar data

Accurate Digital Terrain Models (DTMs) are inevitable inputs for mapping and analyzing areas subject to natural hazards. Topographic airborne laser scanning has become an established technique to characterize the Earth's surface: lidar provides 3D point clouds allowing for a fine reconstruction of the topography while preserving high frequencies of the relief. For flood hazard modeling, the key step, before going onto terrain modeling, is the discrimination of land and water areas within the delivered point clouds. Therefore, instantaneous shorelines, river banks, and inland waters can be extracted as a basis for more reliable DTM generation. This paper presents an automatic, efficient, and versatile workflow for land/water classification of airborne topographic lidar points, effective at large scales (>300km2). For that purpose, the Support Vector Machine (SVM) method is used as a classification framework and it is embedded in a workflow designed for our specific goal. First, a restricted but carefully designed set of features, based only on 3D lidar point coordinates and flightline information, is defined as classifier input. Then, the SVM learning step is performed on small but well-targeted areas thanks to a semi-automatic region growing strategy. Finally, label probability output by SVM is merged with contextual knowledge during a probabilistic relaxation step in order to remove pixel-wise misclassification. Results show that a survey of hundreds of millions of points are labeled with high accuracy (>95% in most cases for coastal areas, and >90% for rivers) and that small natural and anthropic features of interest are still well classified even though we work at low point densities (0.5–4pts/m2). We also noticed that it may fail in water-logged areas. Nevertheless, our approach remains valid for regional and national mapping purposes, coasts and rivers, and provides a strong basis for further discrimination of land-cover classes and coastal habitats.