Relationship of Obligate Grassland Birds to Landscape Structure in Wisconsin

ABSTRACT Conservation plans for grassland birds have included recommendations at the landscape level, but species' responses to landscape structure are variable. We studied the relationships between grassland bird abundances and landscape structure in 800-ha landscapes in Wisconsin, USA, using roadside surveys. Of 9 species considered, abundances of only 4 species differed among landscapes with varying amounts of grassland and forest. Landscape variables explained <20% of variation in abundances for 4 of the 5 rarest species in our study. Our results suggest landscape-based management plans for grassland birds might not benefit the rarest species and, thus, plans should incorporate species-specific habitat preferences for these species.     

Projecting marine species range shifts from only temperature can mask climate vulnerability

Climate change is causing range shifts in many marine species, with implications for biodiversity and fisheries. Previous research has mainly focused on how species' ranges will respond to changing ocean temperatures, without accounting for other environmental covariates that could affect future distribution patterns. Here, we integrate habitat suitability modeling approaches, a high‐resolution global climate model projection, and detailed fishery‐independent and ‐dependent faunal datasets from one of the most extensively monitored marine ecosystems—the U.S. Northeast Shelf. We project the responses of 125 species in this region to climate‐driven changes in multiple oceanographic factors (e.g., ocean temperature, salinity, sea surface height) and seabed characteristics (i.e., rugosity and depth). Comparing model outputs based on ocean temperature and seabed characteristics to those that also incorporated salinity and sea surface height (proxies for primary productivity and ocean circulation features), we explored how an emphasis on ocean temperature in projecting species' range shifts can impact assessments of species' climate vulnerability. We found that multifactor habitat suitability models performed better in explaining and predicting species historical distribution patterns than temperature‐based models. We also found that multifactor models provided more concerning assessments of species' future distribution patterns than temperature‐based models, projecting that species' ranges will largely shift northward and become more contracted and fragmented over time. Our results suggest that using ocean temperature as a primary determinant of range shifts can significantly alter projections, masking species' climate vulnerability, and potentially forestalling proactive management.     

Mosquitoes of field and forest: the scale of habitat segregation in a diverse mosquito assemblage

Knowledge of the distribution of arthropod vectors across a landscape is important in determining the risk for vector‐borne disease. This has been well explored for ticks, but not for mosquitoes, despite their importance in the transmission of a variety of pathogens. This study examined the importance of habitat, habitat edges, and the scale at which mosquito abundance and diversity vary in a rural landscape by trapping along transects from grassland areas into forest patches. Significant patterns of vector diversity and distinct mosquito assemblages across habitats were found. The scale of individual species' responses to habitat edges was often dramatic, with several species rarely straying even 10 m from the edge. The present results suggest blood‐seeking mosquito species are faithful to certain habitats, which has consequences for patterns of vector diversity and risk for pathogen transmission. This implies that analysts of risk for pathogen transmission and foci of control, and developers of land management strategies should assess habitat at a finer scale than previously considered.     

Kaimanawa Feral Horses and Their Environmental Impacts

Feral horses (Equus caballus L.) occupy 64 000 ha of montane- subalpine tussock grassland in the south-western Kaimanawa Mountains, an area zoned for military training. Since 1979, the population has increased at 16.7% per annum, reaching 1102 in 1990. The most extensive habitat, red tussock (Chionochloa rubra) grassland, was variably affected by horses; tussocks in restricted mesic sites were heavily grazed and mostly eliminated, but those in extensive xeric grasslands showed little impact. The mixed hard tussock (Festuca novaezelandiae)/red tussock grasslands on basin floors and plateaux, which had already been degraded by early European farming, were suffering further depletion from horse grazing. The restricted, high altitude Chionochloa pallens tussock communities were being eliminated rapidly through preferential grazing. Oligotrophic bogs, on the summits and basin floors were largely intact, whereas high nutrient flushes were severely affected by trampling and grazing. Horses appeared to have had little impact upon Nothofagus forest understoreys. Ten plant species, several of which are vulnerable nationally, occur in the North Island only within the wild horse range. The habitats of five of them were damaged by horses. Throughout the wide basins and plateaux of the north, horses compromised floristic, rare plant habitat, and landscape nature conservation values. Their numbers may therefore have to be controlled.     

Rangewide landscape genetics of an endemic Pacific northwestern salamander

A species' genetic structure often varies in response to ecological and landscape processes that differ throughout the species' geographic range, yet landscape genetics studies are rarely spatially replicated. The Cope's giant salamander (Dicamptodon copei) is a neotenic, dispersal‐limited amphibian with a restricted geographic range in the Pacific northwestern USA. We investigated which landscape factors affect D. copei gene flow in three regions spanning the species' range, which vary in climate, landcover and degree of anthropogenic disturbance. Least cost paths and Circuitscape resistance analyses revealed that gene flow patterns vary across the species' range, with unique combinations of landscape variables affecting gene flow in different regions. Populations in the northern coastal portions of the range had relatively high gene flow, largely facilitated by stream and river networks. Near the southeastern edge of the species' range, gene flow was more restricted overall, with relatively less facilitation by streams and more limitation by heat load index and fragmented forest cover. These results suggested that the landscape is more difficult for individuals to disperse through at the southeastern edge of the species' range, with terrestrial habitat desiccation factors becoming more limiting to gene flow. We suggest that caution be used when attempting to extrapolate landscape genetic models and conservation measures from one portion of a species' range to another.     

近40年野骆驼历史分布区土地利用变化及生境破碎化驱动因素

野骆驼是中亚地区重要的迁徙物种,历史上完整、连续的野骆驼栖息地目前已成为孤岛状。为了解野骆驼历史分布区受人类活动的影响,明确造成其历史分布区破碎化的驱动因素,研究选取土地利用和道路两个因素,通过对近40年来的野骆驼历史分布区土地利用变化和动态度分析,以及道路密度和影响域计算,定量评估野骆驼历史分布区景观格局,以期为野骆驼栖息地整体连通性的改善,避免或缓解线性基础设施建设对野骆驼栖息地的影响提供科学的建议。结果表明：（1）近40年,野骆驼历史分布区内以未利用土地和草地为主体的格局保持不变,尤其是沙地、戈壁为主的未利用土地始终占比很大（>80%）;（2）野骆驼历史分布区范围内道路密度为0.0410 km/km²,但道路的阻隔作用明显,野骆驼当前分布区呈3个孤岛的格局与道路隔离形成的景观格局是一致的;（3）野骆驼历史分布区斑块数为914个,西部历史分布区斑块数为78个,远低于中部的373个和东部的463个,斑块数和平均斑块面积两个景观指数表明西部的栖息地破碎化程度比中部和东部栖息地要低;（4）从最大斑块指数来看,残存的大面积、无路区斑块是当前野骆驼种群得以存续的庇护所。根据当前的景观格局和破碎化状况,西部分布区和中部分布区间通过实施科学的栖息地连通和廊道建设规划,将极有可能实现两个孤立种群的交流连通,中部分布区和东部分布区间种群已基本无连通的可能。建议将更多的保护资源和努力投入到西部和中部分布区种群的维持和连通。在未来的道路规划建设和布局中,要考虑道路规划和建设对野骆驼最小生境面积的影响,并且要将影响评估尺度放大到整个野骆驼历史分布区的尺度上考虑道路的阻隔作用。     

Landscape‐scale habitat availability,and not local geography,predicts migratory landbird stopover across the Gulf of Maine

While it is clear that many migratory behaviors are shared across taxa, generalizable models that predict the distribution and abundance of migrating taxa at the landscape scale are rare. In migratory landbirds, ephemeral concentrations of refueling birds indicate that individual behaviors sometimes produce large epiphenomena in particular geographic locations. Identifying landscape factors that predict the distribution and abundance of birds during migratory stopover will both improve our understanding of the migratory process and assist in broad, regionally relevant conservation. In this study we used autumnal passerine stopover data from a five‐year period and eleven stopover sites across coastal Maine, USA, to test four broad hypotheses of migrant distribution and abundance that have been supported in other regions: a) the community characteristics of the pool of potential migrants, b) a site's local geography, c) landscape composition and configuration measured at different spatial scales, and d) interactions between these factors. Our final model revealed that birds concentrate at ‘habitat islands’, sites that possess a disproportionate percentage of the vegetated habitat in the 4‐km surrounding landscape. The strength of this pattern, however, was inversely proportional to a species' remaining migratory distance. Our results corroborate several studies that emphasize the importance of land cover composition at finer spatial scales (< 80 km²) for predicting the stopover distribution and abundances of migratory birds. This suggests that different migrants likely assess stopover sites with similar mechanisms along their migratory route, and these commonalities may be broadly applied to identify stopover locations of conservation importance across the continent.     

Conservation of New Zealand's tussock grassland moth fauna

New Zealand has a relatively rich moth fauna associated with tussock grasslands, reflecting the historic importance of plant communities containing native grasses in the New Zealand landscape. Extensive grassland communities were most common in the eastern and central regions of New Zealand’s South Island where what now remains of these communities is contained within more than 350 Pastoral Leases managed for pastoral farming. Because these various grassland communities are distributed from coastal areas to the limit of vegetation on mountains there has been an uneven human impact. Grasslands at sea-level (including those on sand dunes and alluvial plains) have almost been eliminated while those in montane valleys have until now escaped intensive development. Alpine grasslands, like those of montane areas are now much less woody as a result of both Polynesian and more recent burning. From the late 1970s, based on public concern that continuing development was eliminating the natural landscapes and conservation values of the distinctive tussock grasslands of the South Island, a concerted programme of identification of the broad conservation values of the remaining grassland dominated regions was initiated. Implementation of the recommendations in the resulting published reports relating to priority areas for conservation and the subsequent full-scale review of Pastoral Leases has resulted in the formation of large grassland Conservation Parks and the reservation of a multitude of smaller areas, based on a suite of recreation, landscape and biological values. This important ongoing Tenure Review process has important implications for the conservation of tussock grassland biota including numerous native moths and their habitats.     

Vanishing islands in the sky? A comparison of correlation- and mechanism-based forecasts of range dynamics for montane salamanders under climate change

Forecasting the effects of climate change on species and populations is a fundamental goal of conservation biology, especially for montane endemics which seemingly are under the greatest threat of extinction given their association with cool, high elevation habitats. Species distribution models (also known as niche models) predict where on the landscape there is suitable habitat for a species of interest. Correlative niche modeling, the most commonly employed approach to predict species' distributions, relies on correlations between species' localities and current environmental data. This type of model could spuriously forecast less future suitable habitat because species' current distributions may not adequately represent their thermal tolerance, and future climate conditions may not be analogous to current conditions. We compared the predicted distributions for three montane species of Plethodon salamanders in the southern Appalachian Mountains of North America using a correlative modeling approach and a mechanistic model. The mechanistic model incorporates species-specific physiology, morphology and behavior to predict an annual energy budget on the landscape. Both modeling approaches performed well at predicting the species' current distributions and predicted that all species could persist in habitats at higher elevation through 2085. The mechanistic model predicted more future suitable habitat than the correlative model. We attribute these differences to the mechanistic approach being able to model shifts in key range-limiting biological processes (changes in surface activity time and energy costs) that the correlative approach cannot. Choice of global circulation model (GCM) contributed significantly to distribution predictions, with a tenfold difference in future suitability based on GCM, indicating that GCM variability should be either directly included in models of species distributions or, indirectly, through the use of multi-model ensemble averages. Our results indicate that correlative models are over-predicting habitat loss for montane species, suggesting a critical need to incorporate mechanisms into forecasts of species' range dynamics.     

Land use patterns within Wattled Crane (Bugeranus carunculatus) home ranges in an agricultural landscape in KwaZulu-Natal,South Africa

There The Wattled Crane Bugeranus carunculatus is one of the top five most threatened bird species in South Africa, with the main threat being the loss of undisturbed breeding habitat. A basic understanding of this species' use of its environment is needed to implement conservation action. This quantitative study focused on determining the home range size of active breeding pairs in the KwaZulu-Natal midlands of South Africa, and assessing the land use composition of these home ranges. Wattled Cranes were found to have an average home range size of 16.64km², consisting mostly of open natural grassland (mean of 75.5% of the overall home range of pairs). Other significant land use contributions to the home ranges were temporary irrigated and dryland cultivated agriculture. The core breeding area (wetland) of the home range constituted only 2.3% of the overall home range size, consisting of similar proportions of both wetland (48.9%) and grassland (51.8%) habitat. This indicates the dependence of Wattled Cranes on specific wetland habitats, surrounded by natural grassland. Wattled Cranes show home range sizes larger than other similar-sized crane species, suggesting that this may be as a result of their large body size and their occupation of highly transformed and fragmented habitats in an agricultural landscape. However, the occurrence of transformed land use types in home ranges suggests that breeding pairs tolerate some degree of disturbance within their home ranges. The home ranges do not appear to be currently restricted by surrounding land use types, indicating that factors other than habitat loss may be contributing to breeding site losses. The study has therefore indicated the need for closer working relationships between conservationists and agricultural communities to promote the conservation of valuable natural grasslands surrounding wetlands.     

Population fluctuations in relation to seasonal habitat preferences of the Swainson's spurfowl, Pternistis swainsonii

Counts on Swainson's spurfowl Pternistis swainsonii were made during 1998–1999 within an intensive, fine‐grained, agricultural landscape to estimate population parameters, seasonal dispersion and habitat preferences. Radio‐transmitters were fitted to four birds to note habitat use and home ranges within the Summer breeding season. During Winter, population densities peaked, and birds exploited agricultural crops extensively. At the onset of Spring, densities dropped as birds paired to establish non‐overlapping breeding territories over a number of habitats with apparently sufficient cover and ‘natural’ food. Expanding grazed grassland appears to be the greatest threat to Swainson's spurfowl due to a lack of cover and food. The matrix of habitats within the landscape plays important roles in the success of this opportunistic spurfowl. Agricultural crops in the Winter sustain the population until the following Summer when natural savanna and ungrazed grasslands provide complementary foraging, nesting and roosting sites.     

Status and conservation of Hinde's Babbler Turdoides hindei,a threatened species in an agricultural landscape

Njoroge, P. & Bennun, L. A. 2000. Status and conservation of Hinde's Babbler Turdoides hindei, a threatened species in an agricultural landscape. Ostrich 71 (1 & 2): 69–72.

Hinde's Babbler is a restricted-range species endemic to Central Kenya. In recent years it appears to have suffered a marked reduction of population within its range. Using active searching and playback of vocalisations, we assessed the species' status in three study areas (Kianyaga, Mukurweini and Machakos) between July 1993 and May 1994. Distribution of the babbler was closely linked to river valleys and swamps, and to the presence of dense thicket vegetation. In Kianyaga and Mukurweini, clearance for intensive cultivation has removed most natural vegetation. Here the babblers rely on small (ranging from 5 m² to 0.81 ha) patches of the exotic weed Lantana camara for shelter and nest sites. In Machakos (a lower altitude site with less rainfall) the birds occurred in riverine thicket that has not yet been cleared. Densities in Machakos were substantially lower (0.81 individuals per km²) than in Kianyaga and Mukurweini (3.8 and 3.0 individuals per km² respectively). A questionnaire survey of local people in Kianyaga showed that killing of birds for food and clearing of Lantana patches are serious threats to this species. Hinde's Babbler occurs in only one small protected area; its conservation within a severely modified agricultural landscape is a substantial challenge that calls for innovative approaches.     

Where do species' geographic ranges stop and why? Landscape impermeability and the Afrotropical avifauna

Although understanding large-scale spatial variation in species'' distributions is a major goal in macroecology, relatively little attention has been paid to the factors limiting species'' ranges. An understanding of these factors may improve predictions of species'' movements in response to global change. We present a measure of landscape impermeability, defined as the proportion of resident species whose ranges end in an area. We quantify and map impermeability for Afrotropical birds and use multi-model inference to assess support for a wide suite of hypotheses about its potential environmental correlates. Non-spatial analyses emphasize the importance of broad-scale environmental patterns of energy availability and habitat heterogeneity in limiting species'' distributions. Conversely, spatial analyses focus attention on small-scale factors of habitat and topographic complexity. These results hold even when only species from the top quartile of range sizes are assessed. All our analyses highlight that range edges are concentrated in heterogeneous habitats. Global change is expected to alter the nature and distribution of such habitats, necessitating range movement by many resident species. Therefore, impermeability provides a simple measure for identifying regions, where continuing global change and human encroachment are likely to cause profound changes in regional diversity patterns.     

Spatial heterogeneity in landscape structure influences dispersal and genetic structure: empirical evidence from a grasshopper in an agricultural landscape

Dispersal may be strongly influenced by landscape and habitat characteristics that could either enhance or restrict movements of organisms. Therefore, spatial heterogeneity in landscape structure could influence gene flow and the spatial structure of populations. In the past decades, agricultural intensification has led to the reduction in grassland surfaces, their fragmentation and intensification. As these changes are not homogeneously distributed in landscapes, they have resulted in spatial heterogeneity with generally less intensified hedged farmland areas remaining alongside streams and rivers. In this study, we assessed spatial pattern of abundance and population genetic structure of a flightless grasshopper species, Pezotettix giornae, based on the surveys of 363 grasslands in a 430‐km² agricultural landscape of western France. Data were analysed using geostatistics and landscape genetics based on microsatellites markers and computer simulations. Results suggested that small‐scale intense dispersal allows this species to survive in intensive agricultural landscapes. A complex spatial genetic structure related to landscape and habitat characteristics was also detected. Two P. giornae genetic clusters bisected by a linear hedged farmland were inferred from clustering analyses. This linear hedged farmland was characterized by high hedgerow and grassland density as well as higher grassland temporal stability that were suspected to slow down dispersal. Computer simulations demonstrated that a linear‐shaped landscape feature limiting dispersal could be detected as a barrier to gene flow and generate the observed genetic pattern. This study illustrates the relevance of using computer simulations to test hypotheses in landscape genetics studies.     

Increases in subsistence farming due to land reform have negligible impact on bird communities in Zimbabwe

Habitat alterations resulting from land‐use change are major drivers of global biodiversity losses. In Africa, these threats are especially severe. For instance, demand to convert land into agricultural uses is leading to increasing areas of drylands in southern and central Africa being transformed for agriculture. In Zimbabwe, a land reform programme provided an opportunity to study the biodiversity response to abrupt habitat modification in part of a 91,000 ha dryland area of semi‐natural savannah used since 1930 for low‐level cattle ranching. Small‐scale subsistence farms were created during 2001–2002 in 65,000 ha of this area, with ranching continuing in the remaining unchanged area. We measured the compositions of bird communities in farmed and ranched land over 8 years, commencing one decade after subsistence farms were established. Over the study period, repeated counts were made along the same 45 transects to assess species'' population changes that may have resulted from trait‐filtering responses to habitat disturbance. In 2012, avian species'' richness was substantially higher (+8.8%) in the farmland bird community than in the unmodified ranched area. Temporal trends over the study period showed increased species'' richness in the ranched area (+12.3%) and farmland (+6.8%). There were increased abundances in birds of most sizes, and in all feeding guilds. New species did not add new functional traits, and no species with distinctive traits were lost in either area. As a result, species'' diversity reduced, and functional redundancy increased by 6.8% in ranched land. By 2020, two decades after part of the ranched savannah was converted into farmland, the compositions of the two bird communities had both changed and became more similar. The broadly benign impact on birds of land conversion into subsistence farms is attributed to the relatively low level of agricultural activity in the farmland and the large regional pool of nonspecialist bird species.     

Home range and habitat selection of northern bobwhite coveys in an agricultural landscape

Northern bobwhites thrive in fine-grained landscapes with a diversity of early succession woodland, grassland, and agriculture-associated habitat types. Bobwhite conservation has proved challenging in the increasingly coarse-grained Midwestern landscape as simplified agricultural cropping systems are implemented at larger spatial scales. Regardless, managing agricultural landscapes on private lands is the primary opportunity to restore bobwhite populations in the Midwestern United States. Although bobwhite habitat requirements are well understood, habitat selection in contemporary Midwestern landscapes is not well understood, especially on private lands where populations are declining. We used compositional analysis to investigate second- (study area) and third- (home range) order habitat selection by radiomarked bobwhite coveys on 4 private land study areas in southwestern Ohio. Mean covey home range size was 26.1 ± 2.2 ha (n = 48). Although home ranges were established in areas with more grassland cover, bobwhites most strongly selected early succession woody habitat (e.g., fencerows and ditches) at all scales, and selection for grassland diminished between the study area and home range scales. Grassland selection varied among sites and was strongest on sites with more row crop area. Woodlots were avoided at the study area scale, but were selected within home ranges. Grassland cover, like that provided by contemporary conservation programs, is an essential component of bobwhite habitat in the Midwest, but our results suggest more emphasis should be placed on early succession woody cover. Woody cover associated with fencerows, ditches, and woodlots adjacent to food sources and breeding habitat will likely improve non-breeding season survival, which is an influential vital rate in northern populations. © 2012 The Wildlife Society.     

Matrix quality and disturbance frequency drive evolution of species behavior at habitat boundaries

Previous theoretical studies suggest that a species' landscape should influence the evolution of its dispersal characteristics, because landscape structure affects the costs and benefits of dispersal. However, these studies have not considered the evolution of boundary crossing, that is, the tendency of animals to cross from habitat to nonhabitat (“matrix”). It is important to understand this dispersal behavior, because of its effects on the probability of population persistence. Boundary‐crossing behavior drives the rate of interaction with matrix, and thus, it influences the rate of movement among populations and the risk of dispersal mortality. We used an individual‐based, spatially explicit model to simulate the evolution of boundary crossing in response to landscape structure. Our simulations predict higher evolved probabilities of boundary crossing in landscapes with more habitat, less fragmented habitat, higher‐quality matrix, and more frequent disturbances (i.e., fewer generations between local population extinction events). Unexpectedly, our simulations also suggest that matrix quality and disturbance frequency have much stronger effects on the evolution of boundary crossing than either habitat amount or habitat fragmentation. Our results suggest that boundary‐crossing responses are most affected by the costs of dispersal through matrix and the benefits of escaping local extinction events. Evolution of optimal behavior at habitat boundaries in response to the landscape may have implications for species in human‐altered landscapes, because this behavior may become suboptimal if the landscape changes faster than the species' evolutionary response to that change. Understanding how matrix quality and habitat disturbance drive evolution of behavior at boundaries, and how this in turn influences the extinction risk of species in human‐altered landscapes should help us identify species of conservation concern and target them for management.     

Land‐use history and fragmentation of traditionally managed grasslands in Scandinavia

Abstract. Plants associated with traditional agricultural landscapes in northern Europe and Scandinavia are subjected to drastic habitat fragmentation. In this paper we discuss species response to fragmentation, against a background of vegetation and land‐use history. Recent evidence suggests that grassland‐forest mosaics have been prevalent long before the onset of human agriculture. We suggest that the creation of infield meadows and outland grazing (during the Iron Age) increased the amount and spatial predictability of grasslands, resulting in plant communities with exceptionally high species densities. Thus, distribution of plant species in the present‐day landscape reflects historical land‐use. This holds also when traditional management has ceased, due to a slow response by many species to abandonment and fragmentation. The distribution patterns are thus not in equilibrium with the present habitat distribution. Fragmentation influences remaining semi‐natural grasslands such that species density is likely to decline as a result of local extinctions and invasion by habitat generalists. However, species that for a long time have been subjected to changing mosaic landscapes may be more resistant to fragmentation than is usually believed. Conservation should focus not only on ‘hot‐spots’ with high species richness, but also consider species dynamics in a landscape context.     

How increasing levels of private land enrollment in conservation agreements affect the population viability of grassland birds

There is a growing recognition that to effectively conserve biodiversity efforts have to extend into the realm of engaging private landowners. Agricultural lands have been particularly attractive targets for integrating conservation and production goals. Changes in hayfield management associated with agricultural intensification, including earlier and more frequent harvests, have a severe impact on grassland birds. Government-administered conservation incentive programs benefit grassland birds by delaying harvest dates on enrolled land to allow nesting pairs to successfully fledge at least one brood during the breeding season. In contrast, hayfields that are mowed during the breeding season support sink populations and may function as ecological traps. We examined the effect of increasing levels of hayfield enrollment on grasshopper sparrow population viability using a spatially-explicit, stage-structured, stochastic model of a grasshopper sparrow metapopulation in an urbanizing region of New Jersey. The probability of metapopulation extinction (POE) decreased as the proportion of enrolled hayfields increased and fell below 10% when about half of all available agricultural land was enrolled. POE also decreased with increasing numbers of enrolled hayfields most likely because hayfield enrollment removes a sink population from the landscape in addition to creating a source population. Our results are encouraging as they demonstrate that extinction risk for this grassland-dependent imperiled species can be reduced without having to protect or manage all remaining grassland habitat in the landscape.     

Extinction debt in fragmented grasslands: paid or not?

Fragmentation of grasslands and forests is considered a major threat to biodiversity. In the case of plants, the effect of fragmentation or landscape context is still unclear and published results are divergent. One explanation for this divergence is the slow response of long‐lived plants, creating an extinction debt. However, this has not been empirically confirmed. In this study, data were compiled from broad‐scale studies of grasslands from throughout the world that relate plant diversity to fragmentation effects. Only seven studies from northern Europe, out of a total 61, gave any information on actual habitat fragmentation in time and space. In landscapes with >10% grassland remaining, present‐day species richness was related to past landscape or habitat pattern. In landscapes with <10% grassland remaining, in contrast, plant species richness was more related to contemporary landscape or habitat pattern. Studies from landscapes with >10% grassland remaining supported the concept of an extinction debt, while studies from more fragmented landscapes did not provide any evidence of an extinction debt. In order to make generalisations about historical legacies on species diversity in grasslands it is important to consider a range of highly transformed landscapes, and not only landscapes with a high amount of grassland remaining.