Guillaume DECOCQ

Additional file 5. Spearman rank correlations between latitude and the different climatic, soil and local biotic variables, for each study species separately. Spearman rank correlation coefficients given for each test. C-sign. = mean abundance weighted functional competition signature, GDH = growing degree hours, MAP = mean annual precipitation, S-sign. = mean abundance weighted functional stress signature, soil N = soil nitrogen, soil P = soil phosphorous. Significance: (*): 0.10 ≥ P-value > 0.05 *: 0.05 ≥ P-value > 0.01; **: 0.01 ≥ P-value > 0.001; ***: 0.001 ≥ P-value.

Additional file 2. The full dataset used for this study. Study species, study region, population code, all trait SD's and CV's, latitude and all abiotic and biotic predictors given for each sampled population of Anemone nemorosa, Milium effusum and Impatiens glandulifera. C-signature = mean abundance weighted functional competition signature, CV = coefficient of variation, GDH = growing degree hours, MAP = mean annual precipitation, NA = not available, S-signature = mean abundance weighted functional stress signature, SD = standard deviation, soil N = soil nitrogen, soil P = soil phosphorous.

The synergies between remote sensing technologies and ecological research have opened new avenues for the study of alien plant invasions worldwide. Such scientific advances have greatly improved our capacity to issue warnings, develop early-response systems and assess the impacts of alien plant invasions on biodiversity and ecosystem functioning. Hitherto, practical applications of remote sensing approaches to support nature conservation actions are lagging far behind scientific advances. Yet, for some of these technologies, knowledge transfer is difficult due to the complexity of the different data handling procedures and the huge amounts of data it involves per spatial unit. In this context, the next logical step is to develop clear guidelines for the application of remote sensing data to monitor and assess the impacts of alien plant invasions, that enable scientists, landscape managers and policy makers to fully exploit the tools which are currently available. It is desirable to ...

The tick Ixodes ricinus has considerable impact on the health of humans and other terrestrial animals because it transmits several tick-borne pathogens (TBPs) such as B. burgdorferi (sensu lato), which causes Lyme borreliosis (LB). Small forest patches of agricultural landscapes provide many ecosystem services and also the disservice of LB risk. Biotic interactions and environmental filtering shape tick host communities distinctively between specific regions of Europe, which makes evaluating the dilution effect hypothesis and its influence across various scales challenging. Latitude, macroclimate, landscape and habitat properties drive both hosts and ticks and are comparable metrics across Europe. Therefore, we instead assess these environmental drivers as indicators and determine their respective roles for the prevalence of B. burgdorferi in I. ricinus. We sampled I. ricinus and measured environmental properties of macroclimate, landscape and habitat quality of forest patches in ag...

Elevated atmospheric input of nitrogen (N) is currently affecting plant biodiversity and ecosystem functioning. The growth and survival of numerous plant species is known to respond strongly to N fertilization. Yet, few studies have assessed the effects of N deposition on seed quality and reproductive performance, which is an important life-history stage of plants. Here we address this knowledge gap by assessing the effects of atmospheric N deposition on seed quality of the ancient forest herb Anemone nemorosa using two complementary approaches. By taking advantage of the wide spatiotemporal variation in N deposition rates in pan-European temperate and boreal forests over two years, we detected positive effects of N deposition on the N concentration (percentage N per unit seed mass, increased from 2.8 to 4.1%) and N content (total N mass per seed, more than doubled) of A. nemorosa seeds. In a complementary experiment, we applied ammonium nitrate to aboveground plant tissues and the ...

The importance of intraspecific trait variation (ITV) is increasingly acknowledged among plant ecologists. However, our understanding of what drives ITV between individual plants (ITVBI) at the population level is still limited. Contrasting theoretical hypotheses state that ITVBI can be either suppressed (stress-reduced plasticity hypothesis) or enhanced (stress-induced variability hypothesis) under high abiotic stress. Similarly, other hypotheses predict either suppressed (niche packing hypothesis) or enhanced ITVBI (individual variation hypothesis) under high niche packing in species rich communities. In this study we assess the relative effects of both abiotic and biotic niche effects on ITVBI of four functional traits (leaf area, specific leaf area, plant height and seed mass), for three herbaceous plant species across a 2300 km long gradient in Europe. The study species were the slow colonizing Anemone nemorosa, a species with intermediate colonization rates, Milium effusum, an...

The contemporary state of functional traits and species richness in plant communities depends on legacy effects of past disturbances. Whether temporal responses of community properties to current environmental changes are altered by such legacies is, however, unknown. We expect global environmental changes to interact with land-use legacies given different community trajectories initiated by prior management, and subsequent responses to altered resources and conditions. We tested this expectation for species richness and functional traits using 1814 survey-resurvey plot pairs of understorey communities from 40 European temperate forest datasets, syntheses of management transitions since the year 1800, and a trait database. We also examined how plant community indicators of resources and conditions changed in response to management legacies and environmental change. Community trajectories were clearly influenced by interactions between management legacies from over 200 years ago and ...

The castor bean tick (Ixodes ricinus) transmits infectious diseases such as Lyme borreliosis, which constitutes an important ecosystem disservice. Despite many local studies, a comprehensive understanding of the key drivers of tick abundance at the continental scale is still lacking. We analyze a large set of environmental factors as potential drivers of I. ricinus abundance. Our multi-scale study was carried out in deciduous forest fragments dispersed within two contrasting rural landscapes of eight regions, along a macroclimatic gradient stretching from southern France to central Sweden and Estonia. We surveyed the abundance of I. ricinus, plant community composition, forest structure and soil properties and compiled data on landscape structure, macroclimate and habitat properties. We used linear mixed models to analyze patterns and derived the relative importance of the significant drivers. Many drivers had, on their own, either a moderate or small explanatory value for the abund...

Global biodiversity is affected by numerous environmental drivers. Yet, the extent to which global environmental changes contribute to changes in local diversity is poorly understood. We investigated biodiversity changes in a meta-analysis of 39 resurvey studies in European temperate forests (3988 vegetation records in total, 17-75 years between the two surveys) by assessing the importance of (i) coarse-resolution (i.e., among sites) vs. fine-resolution (i.e., within sites) environmental differences and (ii) changing environmental conditions between surveys. Our results clarify the mechanisms underlying the direction and magnitude of local-scale biodiversity changes. While not detecting any net local diversity loss, we observed considerable among-site variation, partly explained by temporal changes in light availability (a local driver) and density of large herbivores (a regional driver). Furthermore, strong evidence was found that presurvey levels of nitrogen deposition determined ...

ABSTRACT Context Determining regional and local processes that govern the maintenance of biodiversity and assessing their relative importance remain major research challenges in landscape ecology. In riparian systems, propagule dispersal and disturbance are constrained by longitudinal and lateral water flows, but riparian forests in temperate human-dominated landscapes have received little attention so far. Objectives We investigated how the longitudinal position along the river course and the lateral position to the riverbed structure forest plant communities subjected to flooding. Methods We studied vegetation, soil seed bank, hydrochorous seed rain and environmental conditions along 23 transects perpendicular to the river in two forest floodplains in the North of France. We used generalized linear mixed models to assess the relative importance of longitudinal distance, relative elevation, and their interaction on both species richness in a given compartment and species turnover between compartments. Results Relative elevation to the riverbed was the main factor explaining species richness of vegetation and water seed deposit, but not of the seed bank. Vegetation was the most species-rich at low elevations, where the number of water-dispersed seeds and related species richness were maximal. The longitudinal position within the riparian forest had no effect on vegetation and seed bank richness. Dissimilarity between the seed bank and the seed rain increased with relative elevation. Conclusion Lateral much more than longitudinal movements of water create a strong gradient in seed rain intensity that structures plant communities. Flooding is important to species dispersal, hence to the conservation of species-rich plant communities within human-pressured landscapes.

Significance Around the globe, climate warming is increasing the dominance of warm-adapted species—a process described as “thermophilization.” However, thermophilization often lags behind warming of the climate itself, with some recent studies showing no response at all. Using a unique database of more than 1,400 resurveyed vegetation plots in forests across Europe and North America, we document significant thermophilization of understory vegetation. However, the response to macroclimate warming was attenuated in forests whose canopies have become denser. This microclimatic effect likely reflects cooler forest-floor temperatures via increased shading during the growing season in denser forests. Because standing stocks of trees have increased in many temperate forests in recent decades, microclimate may commonly buffer understory plant responses to macroclimate warming.

AbstractQuestion: Does shifting cultivation contribute to plant diversity in an Afrotropical semi-deciduous forest lacking large-scale natural disturbance?Does shifting cultivation contribute to plant diversity in an Afrotropical semi-deciduous forest lacking large-scale natural disturbance?Location: Sanaimbo forest, Côte d'Ivoire (Ivory Coast).Sanaimbo forest, Côte d'Ivoire (Ivory Coast).Methods: We surveyed species assemblages, structural attributes of diversity, and life-history traits along a 30-year chronosequence of abandoned fields, comparatively to old-growth and selectively logged forest stands.We surveyed species assemblages, structural attributes of diversity, and life-history traits along a 30-year chronosequence of abandoned fields, comparatively to old-growth and selectively logged forest stands.Results: Patterns of species assemblages strongly changed with fallow area age, with respect to species'light requirements, suggesting niche partitioning along the successional gradient. Species richness, diversity and equitability were all increasing along this gradient. There were clear shifts in life-history traits spectra as the forest recovered, especially regarding leaf shape, lifespan and hairiness, diaspore dispersal, seed size, resprouting capacity, and life forms. Early colonization by the invasive Chromolaena odorata did not appear to impair secondary succession. Soil type influenced old-growth forest vegetation but not fallow vegetation. After 30 years of forest regrowth, plant communities exhibited endemism rates similar to those of ancient forests.Patterns of species assemblages strongly changed with fallow area age, with respect to species'light requirements, suggesting niche partitioning along the successional gradient. Species richness, diversity and equitability were all increasing along this gradient. There were clear shifts in life-history traits spectra as the forest recovered, especially regarding leaf shape, lifespan and hairiness, diaspore dispersal, seed size, resprouting capacity, and life forms. Early colonization by the invasive Chromolaena odorata did not appear to impair secondary succession. Soil type influenced old-growth forest vegetation but not fallow vegetation. After 30 years of forest regrowth, plant communities exhibited endemism rates similar to those of ancient forests.Conclusions: Shifting cultivation appears to be a sustainable land use when small-sized fields are embedded in a forest matrix and when agriculture lasts only one to few years, preserves remnant trees, excludes fire and keeps several years between two clearing episodes. It may even contribute to the high biodiversity maintenance at the whole forest scale, by conserving the successional mosaic. However, conservation of old-growth forest patches is required for a number of climax tree species.Shifting cultivation appears to be a sustainable land use when small-sized fields are embedded in a forest matrix and when agriculture lasts only one to few years, preserves remnant trees, excludes fire and keeps several years between two clearing episodes. It may even contribute to the high biodiversity maintenance at the whole forest scale, by conserving the successional mosaic. However, conservation of old-growth forest patches is required for a number of climax tree species.

Intravenous immunoglobulins (i.v.IG) are increasingly used in various clinical situations for which they have been considered to be safe and effective. However, since 1987, some cases of renal toxicity have been reported. Forty-nine cases of acute renal failure have been notified to the French Regional Pharmacovigilance Centers between 1992 and mid 1998. In this series, marked serum creatinine increases (mean 387%+/-181%) appeared within 8 h to 8 days after initiation of i.v.IG therapy. Oliguria was observed in 80% of the cases. Haemodialysis was required for 34% of the patients. The renal failure persisted for a mean duration of 10 days after discontinuation of the i.v.IG treatment. Although risk factors have not been definitely established, preexisting renal impairment and old age seem to predispose to i.v.IG-associated acute renal failure as well as diabetes mellitus or the use of diuretics. The mechanism of renal injury remains speculative but a hyperoncotic overloading may be contributory. Finally, close monitoring of renal function is required in patients with preexisting renal failure, with older age and with diabetes mellitus.

Synthetic coumarin (benzopyrone) was launched in France in 1988 for the adjuvant therapy of lymphoedema of the upper limb following radiosurgical treatment of breast cancer. Further to the reporting of hepatic reactions, a national survey has been carried out. The survey dealt with 22 cases reported to the pharmacovigilance regional centres and 20 to Knoll France company (five duplicate cases) up to June 1996. Thirty-four cases corresponding to an elevation of ALT over 2N and/or alkaline phosphatase over 1.5N (criteria chosen for selection in this survey) had been taken into account. Among these cases, a causal relationship was considered likely or probable for 15 of them. Two positive rechallenges were reported. The hepatic reactions observed between 2 to 6 months of treatment in two-thirds of the cases (average dose: 90 mg/day; i.e. recommended dose) was essentially cytolytic in 85% of the cases, with jaundice in 14 cases and hyperbilirubinaemia reported in five other cases. In 23 cases (68%), the increase of ALT exceeded 10N. Of the patients 41% were hospitalized. Severe liver failure with encephalopathy justified liver transplantation once and likely led to encephalopathy and fatal evolution in two other cases. The evolution was favourable in the other cases. The drug was prescribed for other uses than the registered indication in more than 50% of these cases. No risk factors could be identified in the survey. This survey provides a strong signal for potential hepatotoxicity of coumarin (likely due to the production of a reactive metabolite in some patients exhibiting a coumarin 7-hydroxylation deficiency).

Summary— Bupivacaine is the most widely used local anaesthetic in obstetrics for epidural analgesia. Nineteen women (mean age 26.9 ± 5.3 years) who underwent epidural analgesia during labour were included in this study. All parturients received a first injection of 21.8 ± 2.5 mg 0.25% plain bupivacaine. The following administrations were given on request: 0.25% concentration was used when cervix uteri was supple, and a 0.375% concentration when it was tonic. Blood samples were collected 5 min after the first injection and then every 30 min until delivery. At delivery blood samples were collected from the infant umbilical cord vein and from the arm vein of the mother. Bupivacaine was assayed by high pressure liquid chromatography. Serum data were analyzed for each patient using a non-compartmental model. Bupivacaine was rapidly detected in serum, and maximal concentration was reached between 5 and 35 min. Pharmacokinetic parameters were estimated in 17 women after the first injection: 87 ± 35 min for elimination half-life, 60 ± 19 L for apparent volume of distribution and 0.5 ± 0.3 L/min for plasmatic clearance. For a mean total duration of labour and total dose administered of respectively 222 ±115 min and 57.1 ± 28.7 mg, the mean value of the foeto-maternal ratio was 0.29 ±0.10. The infant maximal serum concentration was 0.26 μg/mL. No side effects were spontaneously reported by the parturients and all infants had an Apgar score of 10 at 5 min after the delivery. We confirm the fast systemic absorption and rapid elimination of bupivacaine which may be used without risk of acute toxicity both in mother and child, even when it is used in a 0.375% concentration.

This research investigates why the invasive American black cherry tends to dominate the forest canopy on well-drained, nutrient-poor soils, but usually hardly establishes on both waterlogged and calcareous soils in its exotic range. Prunus serotina was sampled from four soil types and two light conditions, to measure (1) radial growth; (2) height growth compared to the main native competitor, Fagus sylvatica; (3) leaf traits; (4) seed production; and (5) rate of fungal attack. We found that P. serotina invested a significant amount of energy in height growth and seed production on well-drained, nutrient-poor soils. These characteristics enabled it to rapidly capture canopy gaps and subsequently exert a mass effect on neighbouring stands. On moist soils, we found irregular growth patterns and high rates of fungal attack, while on calcareous soils, leaf traits suggested a low nitrogen assimilation rate, limiting the production of N-containing compounds. We conclude that P. serotina fails on waterlogged and calcareous soils because it is unable to allocate sufficient energy to fruiting and/or height growth. Conversely, it succeeds on well-drained, nutrient-poor soils because of high fitness which increases its invasiveness.

Past land use is an important factor determining vegetation in temperate deciduous forests. Little is known about the long-term persistence of these impacts on vegetation but especially on the seed bank. This study assessed whether soil characteristics remain altered 1,600 years after human occupation and if this yielded persistent differences in forest plant communities and their seed bank in particular. Compiègne forest is located in northern-France and has a history of continuous forest cover since the end of Roman times. Twenty-four Gallo-Roman and 24 unoccupied sites were sampled and data were analysed using paired sample tests to investigate whether soil, vegetation and seed bank still differed significantly. The soil was persistently altered on the Gallo-Roman sites resulting in elevated phosphorus levels and pH (dependent on initial soil conditions) which translated into increased vegetation and seed bank species richness. Though spatially isolated, Gallo-Roman sites supported both a homogenized vegetation and seed bank. Vegetation differences were not the only driver behind seed bank differences. Similarity between vegetation and seed bank was low and the possibility existed that agricultural ruderals were introduced via the former land use. Ancient human occupation leaves a persistent trace on forest soil, vegetation and seed bank and appears to do so at least 1,600 years after the former occupation. The geochemical alterations created an entirely different habitat causing not only vegetation but also the seed bank to have altered and homogenized composition and characteristics. Seed bank differences likely persisted by the traditional forest management and altered forest environment.

We investigated the relationships between the overstory dominance of Prunus serotina, and the functional diversity of the understory plant communities, in a managed European forest. Vegetation, habitat characteristics and disturbance history were surveyed in 32 invaded stands vs. 32 paired uninvaded stands, after a random stratification. Community specialization and functional diversity indices were compared and a RLQ analysis was run to link species traits to environmental variables. The herb layer of invaded stands exhibited significantly more specialist species and a lower trait diversity compared to uninvaded stands, with respect of species richness and vegetation cover. Light arrival to the forest floor and soil properties explained most of the variation in the RLQ analysis, but 20% of the variation strongly correlated with P. serotina dominance and associated disturbances. Traits characterizing shade-tolerant, short-living ruderals and shade-avoiders (vernal geophytes) were significantly associated to invaded stands, while those associated to light-demanding graminoids characterized uninvaded stands. The establishment of functionally close species (seedlings and saplings of native woody species) tended to be lower in invaded stands. We concluded that the invader was becoming the new ecosystem engineer, first by inducing trait convergence and community specialization, thus promoting traits that enable species to capture resources in the new environment it was creating, and second by reducing the grain of local heterogeneities.

Whether non-native plant invasions are causes, consequences, or independent of the low species diversity in recipient ecosystems remains a debated question. We tried to test these three hypotheses in the special case of the American black cherry (Prunus serotina Ehrh.), a gap-dependent tree species, which is invading European temperate forests. We compared plant communities, soil properties, and disturbance history between P. serotina-invaded and uninvaded paired-stands in a managed mixed forest. Relationships between invasion, disturbances, plant communities, and environmental conditions were investigated using redundancy analyses with variation partitioning. Several soil characteristics differed between paired stands, but were rather components of stand invasibility than invasion effects, except for topsoil available phosphorus. The disturbance history was similar among paired stands except for the amount of storm-induced tree falls, which correlated with the invader's density. Wild boar-disturbed soil areas were more important beneath P. serotina canopies, suggesting a positive feedback on its own establishment. Overall, species assemblages in invaded and uninvaded stands were similar; their ecological inconsistency suggested a management-sustained non-equilibrium. Habitat conditions and disturbances explained most of the variation in both plant diversity and P. serotina density, the last two factors exhibiting a weak direct association. We conclude that in managed forest ecosystems where plant communities are mainly driven by non-interactive factors and immigration processes, non-native plant species can naturalize without being directly influenced by measured features of the plant community in the receiving environment on the short term.

The effect of environmental heterogeneity on spatial spread of invasive species has received little attention in the literature. Altering landscape heterogeneity may be a suitable strategy to control invaders in man-made landscapes. We use a population-based, spatially realistic matrix model to explore mechanisms underlying the observed invasion patterns of an alien tree species, Prunus serotina Ehrh., in a heterogeneous managed forest. By altering several parameters in the simulation, we test for various hypotheses regarding the role of several mechanisms on invasion dynamics, including spatial heterogeneity, seed dispersers, site of first introduction, large-scale natural disturbances, and forest management. We observe that landscape heterogeneity makes the invasion highly directional resulting from two mechanisms: (1) irregular jumps, which occur rarely via long-distance dispersers and create new founder populations in distant suitable areas, and (2) regular, continuous diffusion toward adjacent cells via short- and mid-distance vectors. At the landscape scale, spatial heterogeneity increases the invasion speed but decreases the final invasion extent. Hence, natural disturbances (such as severe storms) appear to facilitate invasion spread, while forest management can have contrasting effects such as decreasing invasibility at the stand scale by increasing the proportion of light interception at the canopy level. The site of initial introduction influences the invasion process but without altering the final outcome. Our model represents the real landscape and incorporates the range of dispersal modes, making it a powerful tool to explore the interactions between environmental heterogeneity and invasion dynamics, as well as for managing plant invaders.

Aim  To investigate the effect of temperature, latitude and local environment on the reproductive traits of widespread perennial forest herbs to better understand the potential impacts of rising temperatures on their population dynamics and colonization capacities.Location  Six regions along a latitudinal gradient from France to Sweden.Methods  Within each region, we collected data from three to five populations of up to six species. For each species, several variables were recorded in each region (temperature, latitude) and population (local abiotic and biotic environmental variables), and seed production and germination were estimated. Resource investment in reproduction (RIR) was quantified as seed number × seed mass, while germinable seed output (GSO) was expressed as seed number × germination percentage. We performed linear regression and mixed effect models to investigate the effects of temperature (growing degree hours), latitude and local abiotic and biotic environment on RIR and GSO.Results  Temperature and latitude explained most of the variation in RIR and GSO for early flowering species with a northerly distribution range edge (Anemone nemorosa, Paris quadrifolia and Oxalis acetosella). Reproduction of the more southerly distributed species (Brachypodium sylvaticum, Circaea lutetiana and Primula elatior), in contrast, was independent of temperature/latitude. In the late summer species, B. sylvaticum and C. lutetiana, variation in RIR and GSO was best explained by local environmental variables, while none of the investigated variables appeared to be related to reproduction in P. elatior.Main conclusions  We showed that reproduction of only two early flowering, northerly distributed species was related to temperature. This suggests that the potential reproductive response of forest herbs to climate warming partly depends on their phenology and distribution, but also that the response is to some extent species dependent. These findings should be taken into account when predictions about future shifts in distribution range are made.

Alien plant invasions contribute significantly to global changes by often affecting biodiversity and ecosystem processes. Operational methods for identifying landscape attributes that promote or constrain plant invasions are urgently needed to predict their future spread and manage them efficiently. We combined landscape and functional ecology concepts to define patch mosaic functional types (PMFTs) as groups of cells showing the same response to a plant invasion in a heterogeneous forest landscape. The invasion of a European temperate forest by the American black cherry (Prunus serotina) has been chosen as a case study. A set of variables was collected, mapped using a Geographic Information System, and analyzed with multivariate analyses to correlate landscape traits with Prunus serotina abundance in each cell of a grid overlaid on the forest. A risk index was derived and mapped for three invasion levels: seedling colonization, tree establishment, and ecosystem invasion. Five PMFTs were identified and characterized by a set of traits related to soil properties, land use, disturbance, and invasion history. Scots pine plantations on podzols were the most invasible, while cells dominated by hydromorphic or calcareous soils were the most resistant. Most colonized patch mosaics provided suitable conditions for future establishment and invasion. Being strongly spatially connected, suitable patches provide corridors for Prunus serotina to colonize new parts of the forest. Conversely, the most resistant PMFTs were spatially agglomerated in the south of the forest and could act as a barrier. Colonization, establishment, and invasion risk maps were finally obtained by combining partial risks associated with each landscape trait at the cell scale. Within a heterogeneous landscape, we defined and organized PMFTs into a hierarchy, according to their associated risk for colonization, establishment, or invasion by a given invasive species. Each hierarchical level should be associated with a management strategy aiming at reducing one or more partial risk. Monitoring safe areas, extending cutting rotations, harvesting recently colonized stands tree by tree, promoting a multilayered understory vegetation, cutting down reproducing alien trees, favoring shade-tolerant, fast-growing, native tree species, removing alien trees at the leading edge, and proposing soil enrichment or irrigation in heavily invaded areas are recommended.

1Resurveys of regional floras allow assessment of long-term floristic change and to pinpoint driving forces behind these changes. Causes of floristic decline derived from such resurveys depend on the considered landscape, but are often associated with human activities especially in urbanized areas. Much could be learned from comparisons of contrasting landscapes.2Vascular plant abundance categories from a detailed, late 19th century flora were matched with distribution data from a late 20th century plant database in a rural area (Thiérache; 1673 km2) in northern France. Floristic change was characterized both in absolute numbers of extinct and extant species and by a measure for relative change in range size. Knowledge of land use changes and ecological correlates of floristic change permitted the causes for species change to be inferred and to identify which traits are associated with species vulnerability. Extinction rates were compared with similar studies from contrasting landscapes, taking into account the negative relationship between standardized extinction rates and log-transformed size of the study area.3Of the 959 species from the historical list, 186 (19.4%) may be considered regionally extinct. Most extinct species were already rare historically. Differences among habitats indicated strong declines for aquatic species and arable weeds and least change for forest species. Percentage species loss per year in Thiérache equalled 0.22, which was higher than two other similar sized predominantly rural landscapes.4Across the main habitat groups, relative species decline was always associated with relatively higher stress tolerance and lower competitiveness and biased towards therophytes. The main causes of species decline were management intensification, eutrophication, secondary succession in semi-natural open habitats and land use change.5Synthesis. Rural landscapes with no population density increase, no urbanization and a stable landscape configuration are believed to be less vulnerable; yet, on a relatively short time scale, without nature conservation measures, these landscapes may suffer strong species loss comparable to that in urbanized landscapes. Effective management of landscapes for biodiversity conservation whether they are urbanized or rural requires the development of a network of nature reserves.Resurveys of regional floras allow assessment of long-term floristic change and to pinpoint driving forces behind these changes. Causes of floristic decline derived from such resurveys depend on the considered landscape, but are often associated with human activities especially in urbanized areas. Much could be learned from comparisons of contrasting landscapes.Vascular plant abundance categories from a detailed, late 19th century flora were matched with distribution data from a late 20th century plant database in a rural area (Thiérache; 1673 km2) in northern France. Floristic change was characterized both in absolute numbers of extinct and extant species and by a measure for relative change in range size. Knowledge of land use changes and ecological correlates of floristic change permitted the causes for species change to be inferred and to identify which traits are associated with species vulnerability. Extinction rates were compared with similar studies from contrasting landscapes, taking into account the negative relationship between standardized extinction rates and log-transformed size of the study area.Of the 959 species from the historical list, 186 (19.4%) may be considered regionally extinct. Most extinct species were already rare historically. Differences among habitats indicated strong declines for aquatic species and arable weeds and least change for forest species. Percentage species loss per year in Thiérache equalled 0.22, which was higher than two other similar sized predominantly rural landscapes.Across the main habitat groups, relative species decline was always associated with relatively higher stress tolerance and lower competitiveness and biased towards therophytes. The main causes of species decline were management intensification, eutrophication, secondary succession in semi-natural open habitats and land use change.Synthesis. Rural landscapes with no population density increase, no urbanization and a stable landscape configuration are believed to be less vulnerable; yet, on a relatively short time scale, without nature conservation measures, these landscapes may suffer strong species loss comparable to that in urbanized landscapes. Effective management of landscapes for biodiversity conservation whether they are urbanized or rural requires the development of a network of nature reserves.