Using centennial changes in plant, butterfly and bird diversity to inform restoration targets

doi:10.21203/rs.3.rs-6887670/v1

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Using centennial changes in plant, butterfly and bird diversity to inform restoration targets

https://doi.org/10.21203/rs.3.rs-6887670/v1

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Historical records reveal significant biodiversity loss, but over such long timespans that human minds gradually adjust to depauperated biotas. We used 19th and early 20th -century Danish records (100–180 years old) to address this blind spot and enhance our understanding of flora and fauna changes beyond mere richness gains or losses. By analyzing species’ traits, habitat affinities, and environmental indicators, we identified lost habitat types. Compared to the present, 19th-century Danish landscapes were more heterogeneous, featuring open, wooded pastures, now largely replaced by dense plantation forests. Historical data demonstrated that dark diversity is easily underestimated when based on contemporary data. Historical butterfly faunas were much more species-rich and had a stronger affinity for grazed ecosystems than current communities. Declining plant species of conservation interest were more light- and moisture-demanding and less nutrient-affiliated and competitive than persisting species. Declining butterfly species were linked to host plants with restricted national distribution. Declining bird species were typically carnivorous, migratory, and associated with open habitats, particularly grasslands, coastal areas, and freshwater wetlands.

Our findings may guide the ambition level and direction of restoring efforts. The results suggest a restoration focus on open, heterogenous woodland, grassland and wetland ecosystems with low nutrient status and natural disturbance regimes, including populations of large herbivores near carrying capacity. This contrasts sharply with today’s timber-focused plantation forests and conservation area management governed by agricultural subsidies.

biodiversity loss

ecological restoration

biotic homogenization

land-use change

Human activities dominate Earth’s climate systems and biodiversity in the ‘Anthropocene’ (Crutzen 2002), obliterating the traces of past extinction (Johnson et al. 2017). Some researchers consider the Anthropocene epoch to have commenced around 1784, nearly two and a half centuries ago (Crutzen 2002). Since then, pervasive industrialization of agriculture and silviculture, plus urbanization and infrastructure development, have severely impoverished the integrity of ecosystems, both in terms of ecosystem processes and biota (Johnson et al. 2017). Today, we are confronted with a biodiversity crisis driven by human exploitation of natural resources, with species extinction rates up to 100 times higher than natural background rates (Turvey & Crees 2019). Land-use changes, particularly habitat conversion, play a crucial role in biodiversity loss (IPBES 2019). Recognizing the urgency, habitat restoration efforts are gaining momentum. The incentive for successfully restoring European habitats has recently increased with the adoption of the EU Nature Restoration Law, in which member states are obliged to restore at least 20% of the degraded ecosystems by 2030 and all ecosystems in need of restoration by 2050. However, planning and implementing efficient and successful restoration is not an easy task and suffers from a shortage of evidence-based solutions, insufficient pre- and post-restoration monitoring, and preconceived restoration goals (Suding 2011; Cooke et al. 2018). Most importantly, proper restoration must be assessed against natural reference conditions or, at least, historical states, when most ecosystem processes were much less impacted by human activities. Relevant references include knowledge of site appearance, environmental qualities, and species occurrences before degradation (Klein & Thurstan 2016). However, most biodiversity monitoring programs began long after the acceleration of major anthropogenic pressures (Mihoub et al. 2017; Soga & Gaston 2018). While some historical sources, such as diary notes and landscape paintings (Fig. 1), provide fragmentary evidence of the past, they are often subjective or qualitative human perceptions. The gradual degradation of ecosystems (Klein & Thurstan 2016) and our tendency to underestimate historical biodiversity or misinterpret natural processes due to limited awareness of past conditions challenge restoration ambitions. Without accurate records of past near-natural states, restoration goals may be unambitious (Papworth et al. 2009; Vera 2010).

In this study, we present targets for ecological restoration based on historical data on plants, butterflies, birds, and their ecological indicator values and habitat affinities. Denmark, like many European countries, has undergone radical land-use change over the past 100–200 years (Levin & Normander 2008; Finderup Nielsen et al. 2021). The agricultural area has remained relatively constant, even slightly decreasing to around 60% of the total land area since a peak around 1935. Non-arable lands have experienced increasing intensification in recent decades, partly due to spill-over from intensified arable farming (through drainage and fertilization), and partly through the conversion of near-natural areas to plantation forest and cultivated ley (Fig. 1). Official statistics tell that the total forest area has increased from 3–4% in 1805 to 11% around year 2000 (Levin & Normander 2008). However, what used to be semi-open woodlands grazed by livestock have been converted to dark plantations. The area of open habitats, such as grasslands and fens, has decreased from 25% in 1888 to less than 10% in 2000 (Levin & Normander 2008) due to cessation of extensive livestock grazing and subsequent encroachment (Eriksson et al. 2002), and the lack of conservation grazing on the remaining open habitats. Previous studies on historical species data have shown that early 19th -century butterfly, plant, and bird communities were radically different than those of today (Eskildsen et al. 2015; Finderup Nielsen et al. 2019; Finderup Nielsen et al. 2021; Meltofte et al. 2021; Bjerregård et al. 2023).

Our aim is to demonstrate the magnitude of biotic changes over the past 100–180 years. We have selected plants, butterflies, and birds as focus groups because of high data reliability and because they supplement each other in trophic level, mobility, body size etc., corresponding to sensitivity to complementary aspects of habitat change (Newbold et al. 2020). Moreover, plants are important and widely used indicator species (Brunbjerg et al. 2018), while birds and butterflies are some of the most well-studied species’ groups (Gregory et al. 2008; van Swaay et al. 2008). By examining these three groups, we aim to gain a comprehensive understanding of historical conditions, although our knowledge is still limited by the lack of data on the response of understudied taxonomic groups to land-use changes (Davison et al. 2021). Through species traits, habitat preferences, and changes in land use, we seek to answer the following critical questions:

How can historical occurrence data from multiple sources, of variable quality and quantity, from contrasting species groups, and historical land-use statistics be collated to inform restoration targets?

What characterizes (winner and) loser species during the past 100–180 years, considering differences in habitat requirements and dispersal ability?

What landscape-scale changes in habitat quantity and quality can we infer from the observed changes and how can this information be used to inform current restoration efforts?

Plant localities

Based on historical data availability for plants in Denmark (see Finderup Nielsen et al. 2019), we chose 11 focal localities in which reasonably thorough surveys had been conducted 1835-1915 (Fig. 2). These varied in size (range: 1.2-55.2 km²) and habitat composition but generally had high habitat heterogeneity (Supplementary Information S1).

Plant data

We retrieved historical presence-only data for the selected sites from published literature and from unpublished diary notes (Supplementary Information S2). We aimed for thorough, unbiased species lists for well-defined, well-investigated areas sampled by distinguished botanists. These were supplemented with stray records from somewhat earlier and later times but still representing the state of ecosystems before the industrialization of agri- and silviculture. Thus, occurrences spanned 1790-1947 with a mode 1835-1915, and many of the later records being rediscoveries of species already known from the site.

For these localities, we retrieved current (1992-2023) presence-only vascular plant species data from two databases: A national atlas database (Atlas Flora Danica (AFD) 1992-2014 (Hartvig 2015)) and GBIF (1992-2023). We used data with geographic uncertainty < 1 km (99% of the data). For both current and historical data, we aligned taxonomy, aggregated subspecies and varieties to species level, omitted genus-level records and hybrids, and merged species lists, omitting duplicates. Aggregated taxa were constructed due to changes in species circumscription between the 19th century and now: Carex muricata group (C. spicata, C. pairaei, C. divulsa), Glyceria fluitans+G. notata+G. declinata; Malva neglecta+M. pusilla, Nuphar lutea+N. pumila; Polypodium vulgare+P. interjectum; Rorippa nasturtium+R. microphylla; Rosa tomentosa+R. sherardii. Agrostis canina+A. vinealis, Dryopteris dilatata+ D. expansa+D. carthusiana.

The final current plant list had 1307 species, while the historical list had 888 species, including aggregated taxa.

Butterfly data

Butterfly localities matched plant localities, except two localities with no historical records (Pamhule Skov and Jonstrup Vang), i.e. nine localities were used (Supplementary Information S1).

Historical and current butterfly presence/absence data were based on all existing databases (www.naturbasen.dk, www.arter.dk, ADD database (Atlas of Danish Butterflies), Bugbase (https://lepidoptera.dk/), Zoological Museum of Copenhagen collections, Danish Ornithological Society database (https://dofbasen.dk/), various private 20^th century collections, and extensive field work (Bjerregård et al. 2023) and aggregated temporally to three time periods: 1900-1949, 1950-1999, and 2000-2019. There were many indications that historical data had false negative records of species that were historically too common to be considered “noteworthy”, but which have since then declined in occupancy. Thus, for sedentary species (according to Eskildsen et al. 2015), large and stable populations of a species at a given locality during the later time periods was assumed as evidence of presence also in earlier time periods (n = 91 occurrences; Supplementary Information S3). In particular, this was applied to sites, for which historical data came from single excursion reports, giving a seasonal bias. For mobile species, no changes were made. Conversely, stray finds in single years of mobile species were considered false positives and removed (n = 52 occurrences; Supplementary Information S3). The final data comprised 72 butterfly species.

To interpret temporal changes in butterfly communities within localities and relate them to changes in land use, we retrieved data on butterfly host plant distribution for the 72 species in our study from Eskildsen et al. (2015). Habitat openness preference for each species was extracted from the species’ habitat description in Stoltze (1996) and categorized into four classes: open, forest-grassland ecotone, woodland, and habitat generalist.

Bird data

For the avifauna, we analyzed traits of nationally increasing (winners) and declining (losers) Danish breeding bird species from 1800-2018. Meltofte et al. (2021) listed 123 species showing clear trends, either increasing or decreasing (Table 1 in Meltofte et al. 2021, Supplementary Information S4). We used the AVONET database (Tobias et al. 2022) to characterize each species’ properties, including habitat preference, vegetation structure, migration, trophic level, and maximum latitude of range (Supplementary Information S5).

We excluded marine and aquatic bird species from our terrestrial ecosystem study, resulting in 105 species (Supplementary Information S4).

Environmental and land-use data

Ellenberg indicator values (Hill et al. 1999) for nutrients (N), soil moisture (F), light (L) and soil pH (R) were available for 970 of 1298 current species (75%) and 787 of 884 historical species (89%). Similarly, Grime’s life strategy indicators for competition (C), stress (S) and disturbance (R) (Grime et al. 1989) were recoded as numeric values for each species following Ejrnæs & Bruun (2000). Species’ grazing/mowing affinity was retrieved from Tyler et al. (2021) (Supplementary Information S6). Mean and standard deviation Ellenberg, mean CSR and mean Tyler’s grazing/mowing affinity were calculated based on species lists for each locality in each time period.

We estimated current and historical habitat diversity within localities using species-habitat affiliations from the Biolflor database (Kühn et al. 2004). For each period and locality, we calculated the number of habitats represented by the plant species list for the specific locality, focusing on natural habitats relevant to Denmark (Supplementary Information S7). Alpine habitats and highly modified agroecosystems were excluded. To account for differences in locality size and sampling effort (number of observed species), habitat diversity was adjusted by dividing the number of habitats with the log transformed number of species in each locality.

Historical land-use categories from 1881 were retrieved at the parish-level using Danmarks Statistik: Statistisk Tabelværks 4^de række, Litra C, Nr. 4. Land-use classes were aggregated (Supplementary Information S8) and summarized for each locality based on the areal share of each parish located in a locality. Current land-use categories were aggregated to match historical data categories (Supplementary Information S9) and summarized for each locality based on Basemap 04 (Levin 2022) which is a national map of land use and land cover for Denmark.

Mean current grazing density (kg large herbivore biomass per ha) for each locality was retrieved from the Danish Nature Indicator (Ejrnæs et al. 2021, https://naturindikator.dk/).
Historical grazing densities were estimated from national statistics on horses, cattle and sheep at the parish level in 1864 (Danmarks Statistik: Statistisk Tabelværk ser.3, vol. 3, 1864), recalculated to kg/ha using parish areas overlapping with each locality (Danmarks Statistik: Statistisk Tabelværks 4de række, Litra C, Nr. 4 and Dam 2023) and mean body mass for historically common breeds of cattle, horse and sheep (cattle: Jysk Malkekvæg=350 kg, horses: Frederiksborghest=500 kg, sheep: Dansk Landfår=70 kg). Cattle, horse and sheep were known to graze in most grasslands and forests historically, whereas pigs were disregarded here, as they - by the mid-19^th century - were most likely fenced near settlements and no longer roaming freely as pannage pigs. The method assumes that parish-level density is representative for localities and that 1864 livestock mainly fed on wild plants (either grazing or fed locally harvested hay).

Analyses

Plants

We assessed temporal changes in plant species richness by calculating total species richness for each locality. Similarly, we calculated the number of red-listed species (critically endangered, endangered, vulnerable, near threatened, and data deficient) based on the Danish National Red List (www.redlist.au.dk). A few species were matched at subspecies level to retrieve the correct red list category. As a supplement to the red listed species, we used a list of indicator species considered moderately to very sensitive towards habitat changes as defined by Fredshavn et al. (2010). We combined red-listed and indicator species to identify sensitive species lost across localities during the study period. Paired t-tests were employed to compare Ellenberg N, F, L, R and N/R (Andersen et al. 2013) values and Grime C, S, R values between species lost and those remaining in the localities throughout the study period.

Butterflies

To test trends in butterfly species richness per locality for pairs of the three time periods (1900-1949, 1950-1999, and 2000-2019), we used one-tailed, paired t-tests and checked normality with Shapiro-Wilk tests.

We assessed changes in butterfly community composition using nonmetric multidimensional scaling (NMDS) on 72 species across 27 time period-locality combinations using the function metaMDS in the vegan R-package (Oksanen et al. 2017). Dispersion ellipses (0.4 confidence on standard deviations) were drawn for each time period (1900-1949, 1950-1999, and 2000-2019).

We used Mantel test to assess the importance of local environmental variables for butterfly species composition (Legendre & Legendre 1998). A range of dissimilarity matrices were calculated: 1) a species composition dissimilarity matrix based on Sørensen similarity index (only using time periods 1900-1949 and 2000-2019 to match the environmental variables), 2) dissimilarity matrices for Ellenberg L, Ellenberg F, Ellenberg N, Ellenberg R, Grime S, Grime C, Grime R, Biolflor habitat diversity and plant richness based on Euclidean similarity index.

Butterfly species were categorized as winners and losers based on presence/absence of species on each of the localities in two time periods (1900-1949 and 2000-2019) as response variable and ‘time period’ as explanatory variable in a binomial glm. Significant positive estimates indicated winners, while negative estimates indicated losers. The butterfly data set included species found in only a few localities, yet these species are highly important as they may be on the verge of extinction. Because of small sample sizes for some species, we used a significance level of p<0.05 as well as p<0.2 to gain knowledge of the rare species. Differences in ecological traits of winners and losers (p<0.2) were tested using contingency tables for selected traits (host plant distribution and habitat openness) and two-tailed Fischer’s exact test.

Birds

We used contingency tables to test for associations between “species trend” (increasing or decreasing in Table 1 in Meltofte et al. 2021, Supplementary Information S4) and the variables “habitat,” “vegetation structure,” “migration,” and “trophic level”. For the “habitat” variable, two habitats with < 5 species (riverine and rock) were omitted from the analysis. Significance was inferred using two-tailed Fisher's exact tests.

To investigate the potential effect of global warming and northward range shifts in describing bird species trends, we tested for potential differences in “max latitude” between increasing and declining species using the Wilcoxon signed-rank test (Wilcoxon 1945).

Land-use changes

To investigate the potential temporal change in land-use we used paired t-tests on locality mean-values of Ellenberg (L, F, N, R), Grime’s CSR, Tyler’s grazing/mowing affinity, and Biolflor habitat diversity, number of annual plant species and richness of red-listed plant species as well as land-use classes.

All statistical analyses were performed in R version 4.2.2 (R Core team 2022).

Plants

Historical (1790–1947) plant species richness across the 11 localities ranged from 78 to 374 species, while current (1992–2023) richness ranged from 296 to 785 species. Larger localities had more species missing from historical data (estimate = 7.5, p = 0.03). The higher number of species in the current dataset suggests more complete inventories and more neophytes. Therefore, simple comparisons of total species richness trends were not meaningful.

The historical and current dataset had 159 and 116 red-listed species, respectively (Supplementary Information S10), and 341 and 301 sensitive species, respectively. Historical richness of now red-listed species ranged from 10 to 51 species per locality. Current red-listed richness ranges from 4 to 42 species. All sites had substantial losses of species sensitive to human land-use intensification, despite being relatively unaltered compared to the landscape at large. Potentially, several now redlisted could have been lost from the sites prior to the earliest botanical investigation (Fig. 3). Two sites with relatively scanty botanical data (but good butterfly data) deviated from the overall pattern. Moreover, the historical plant communities were more stress-tolerant (Grime S) and had a higher affinity for grazing and mowing than the more competitive (Grime C) current communities (Supplementary Information S12, A, C, D).

Despite fewer recorded species overall, the historical dataset had more red-listed species per locality than current data (absolute numbers: one-tailed t-test: mean difference: 10.5 species, t-value = -2.004, df = 10, p = 0.036; relative numbers: one-tailed t-test: mean difference: 0.092, t-value = -7.104, df = 10, p < 0.001) and the difference was due to a significant difference in red-listed species belonging to the categories EN (one-tailed t-test: mean difference: 3.5 species, t-value = -2.057, df = 10, p = 0.033) and CR (one-tailed t-test: mean difference: 1.2 species, t-value = -2.137, df = 10, p = 0.029).

When comparing Ellenberg and Grime values for red-listed and sensitive species, we found that vanished species were significantly more light- and soil moisture-demanding (Ellenberg L, 7 of 11 localities and Ellenberg F, 5 of 11 localities, respectively), and significantly less nutrient-affiliated (Ellenberg N, 6 of 11 localities, Ellenberg N/R, 5 of 11 localities) and competitive (Grime C, 6 of 11 localities), than species that persisted (Supplementary Information S11).

Butterflies

Butterfly species richness across the nine localities varied from 30 species at Færgelunden to 65 species at Tisvilde (1900–2019). There was a significant decline in species richness across the nine localities from 1900–1949 to 1950–1999 (one-tailed t-test: mean difference: 3.33 species; t = 2.673, df = 8, p-value = 0.014); 1950–1999 to 2000–2019 (one-tailed t-test: mean difference: 8.33 species; t = 3.536, df = 8, p-value = 0.004) and 1900–1949 to 2000–2019 (one-tailed t-test: mean difference: 11.67 species; t = 6.047, df = 8, p-value < 0.001).

The NMDS ordination on butterfly communities (4-dimensional, final stress = 0.047) explained 93.8% of the variation in species composition. Butterfly community composition overlapped along axes 1 and 2, but with distinct ellipses for 1900–1945 and 2000–2019 (Fig. 4).

Mantel tests showed significant correlations between butterfly species composition, Ellenberg N and Grime’s S (Table 1).

Of the 72 butterfly species, 14 were losers and two were winners (p < 0.2), while eight were losers and one was winner using a significance level of p < 0.05 (Supplementary Information S13).

Fisher’s exact test showed significant differences between winners and losers (p < 0.2 level) for host plant distribution (p = 0.042, losers had more local hostplants) and habitat openness (p = 0.008, i.e., losers were associated with open habitats or forest-grassland ecotones).

Birds

Avian trends from 1800 to 2018 showed 60 winners and 45 loser species (Supplementary Information S13). Species preferring forests, woodlands and human-modified landscapes increased, while those associated with grasslands, coastal habitats and freshwater wetlands declined (p < 0.001, Supplementary Information S14). Likewise, vegetation structure was significantly associated with species’ trend (p < 0.001), i.e., species preferring dense habitats were mostly increasing, while species preferring open habitats were generally declining. A significant association between trophic level and species trend (p = 0.002) indicated that carnivorous (mainly insectivorous) species were most often declining, while omnivorous species were mostly increasing. With respect to migration, there was a significant association between migration and species trend (p = 0.02), indicating that migratory species were declining more often than sedentary species. Maximum latitude did not significantly differ between winners and losers (W = 1611, p = 0.092).

Land-use changes

Mean nutrient status (Ellenberg N, mean difference = 0.729, p < 0.001, Supplementary Information S15, D) and pH (Ellenberg R, mean difference = 0.221, p < 0.01, Supplementary Information S15, B) were significantly higher in current communities. The standard deviation of Ellenberg values within localities, indicating ecological heterogeneity, was lower in current than in historical localities for nutrient availability (mean difference = 0.109, p = 0.011, Supplementary Information S15, C) and soil pH (mean difference = 0.263, p < 0.001, Supplementary Information S15, A). There was no significant change in light conditions (Ellenberg L) and soil moisture (Ellenberg F) (Supplementary Information S16).

Habitat diversity and grazing/mowing affinity were significantly lower in current data than historical (mean difference habitat diversity = 0.555, p < 0.005; mean difference grazing/mowing affinity = 0.243, p < 0.005, Supplementary Information S12, D).

The cover of rotational and fallow fields was significantly higher within localities in 1881 than in 2021. Rotational fields decreased from about 39–4% (mean difference = 34.633, p < 0.001, Supplementary Information S17, A), and fallow fields from about 20% to about 4% (mean difference = 15.886, p < 0.01, Supplementary Information S17, D). Forest plantation cover increased significantly from about 24–49% (mean difference = 23.113, p < 0.01, Supplementary Information S17, C). There was no significant change in built-up areas within our localities (Supplementary Information S17, B).

Mire cover increased from about 1–10% (mean difference = 9.059, p < 0.05, Supplementary Information S18, C), while the density of large grazing herbivores decreased from about 173 kg/ha to 20 kg/ha in 2020 (mean difference = 152.975, p < 0.001, Supplementary Information S18, A). This increase in mire cover can be attributed to the abandonment of grazing or neglected drains, leading to overgrowth of wet-moist meadows and subsequently a change in land-cover from meadow to mire.

There was no significant change in meadow and grassland cover (Supplementary Information S18, B and D).

This study investigates the potential of utilizing historical data to assess changes in biodiversity and landscape structure, aiming to inform restoration targets for biodiversity conservation. Significant disparities were found between historical and contemporary landscapes in habitat heterogeneity, plant and butterfly communities, and bird fauna. Historically, landscapes featured heterogeneous mosaics of grasslands and open woodlands with grazing, supporting many rare species. Since then, landscapes have been homogenized, eutrophied, and non-arable become dominated by closed-canopy vegetation, due to the cessation of extensive practices that previously induced ecosystem disturbances (Fig. 1). These processes have driven substantial losses of rare species. Our findings highlight the importance of historical records in guiding ambitious and effective conservation and restoration strategies. Several species of EU-wide conservation concern, but now extinct from Denmark have vanished from the investigated sites (e.g. Hamearis lucina and Parnassius mnemosyne). Similarly, many endangered or regionally extinct plant species had disappeared from one or more of our sites (e.g. Thesium ebracteatum, RE, lost from two sites, Anacamptis pyramidalis, VU, Neotinea ustulata, CR, lost from three sites, Crepis praemorsa, EN, lost from three sites, Supplementary Information S10). This illustrates that ignoring historical data will lead to lowered ambition levels of conservations efforts in countries, where industrialization of land-use took place relatively early.

Centennial changes in landscape, plant, butterfly and bird diversity

Since the industrial revolution, Denmark has undergone significant land-use changes, including intensified agriculture and plantation forestry, causing eutrophication and drainage (Lohrum et al. 2024). These changes have negatively impacted natural areas (www.NOVANA.dk, Fig. 1), aligning with the EU Habitats Directive report that shows 81% of habitats have poor or bad conservation status, with 36% deteriorating (EEA 2020). The extensive 19th-century drainage to boost agriculture and forestry, was revealed by significant differences in red-listed and sensitive plant species, indicating that species lost during the study period preferred higher soil moisture and lighter conditions than those still found.

The shift from rotational field to forest within localities did not increase species richness during the study period. Historically, wood pastures supported a range of species affiliated with forest ecotones. Modern forestry and nature management have sharpened habitat boundaries, reducing ecotones (Habel et al. 2023). Plantation forests, especially those with exotic conifers, negatively impact bird diversity and abundance due to low structural heterogeneity, lack of native species, and short rotation times (Castaño-Villa et al. 2019). Species like Erithacus rubecula, Turdus philomelos, Coccothraustes coccothraustes, Dendrocopos major and Poecile montanus have increased, indicating more forested area (coniferous) and dense vegetation. Some of these species may have benefitted from increased afforestation, while others have likely been favored by the overgrowth of previously open habitats. Similarly, a shift in plant communities towards medium-dry, nutrient rich and shaded conditions has been documented, corresponding to intensified agriculture (eutrophication and drainage) and silviculture (dark, homogenous plantations) (Finderup Nielsen et al. 2021) in line with our findings of species associated with low-growing grassland (Helianthemum nummularium) and fens (Carex dioica, Eriophorum latifolium) as well as open woodland (Lathyrus vernus) disappearing from several localities.

Butterfly richness declined by about 11 species from 1900 to 2019, with species linked to open habitats and host plants with limited distribution being the most affected (e.g., Fabriciana adippe (forest glades), using violets such as Viola hirta as larval host plants). Our results align with early 20th -century declines and regional extinctions of butterfly species associated with forest-grassland ecotones and open woodlands in Denmark and Europe (Streitberger et al. 2012; Bubová et al. 2015; Eskildsen et al. 2015). Habel et al. (2019), found the most significant decline in butterfly abundance in Germany since 1950. This aligns with our finding of a substantial species loss since 1950, despite limitations in our data size and temporal analysis precision. Nevertheless, species sensitive to increased nutrients, intensive grazing, and bog drainage are among the losers, consistent with the effect of unfavorable management practices on red-listed butterflies in Europe (Bubová et al. 2015).

Grazing practices have dramatically changed over the last 150 years, from extensive grazing across habitat types to paddocks of intensive summer grazing and large landscapes ungrazed, leading to litter accumulation, encroachment, and homogenization. 19th -century grazing areas supported greater biodiversity (more red listed and sensitive plant species, more butterflies etc.) due to their heterogeneity, low nutrient status, and near-natural levels of large herbivores often roaming the land year-round creating open habitats and forest-grassland ecotones. Regional floras are more similar today than 140 years ago (Finderup Nielsen et al. 2019), indicating homogenization due to intensive land use. Species richness increased mainly due to exotic species, while rare species became rarer corresponding to our finding that red-listed plant species are declining. This should be considered conservative given the better and more systematic coverage of the current data. For butterflies, the shift in community composition was more pronounced than community homogenization (Fig. 4). Species sensitive to intensive grazing, bog drainage or high nutrient levels also declined (e.g., intensive grazing: Lycaena hippothoe, Polyommatus amandus, bog drainage: Melitaea diamina, Boloria aquilonaris, Supplementary Information S13). Generalist species with nitrophilous host plants such as Vanessa cardui increased, while Apatura iris likely increased due to a northward climate change-driven range shift. Long-term shift and homogenization of communities and their links to landscape and habitat homogenization have been documented previously (e.g., Eskildsen et al. 2015; Warren et al. 2021), and habitat and landscape homogenization negatively affect specialist butterflies more than generalists (Habel et al. 2023), with specialist species preferring nutrient-poor habitats being particularly vulnerable (Habel et al. 2016). For birds, landscape homogenization and agricultural dominance leads to absence of expected bird species (i.e., avian dark diversity) (Andersen et al. 2023). Birds rely on a mosaic of habitats for breeding (Dolman 2012), and agricultural intensification and landscape homogenization have led to declines in open land bird populations across Europe, especially in countries with intensive agriculture like Denmark (Donald et al. 2001; Heldbjerg et al. 2018). In our study, declining bird species were often associated with grasslands, coastal areas and freshwater wetlands (e.g., Perdix perdix, Ciconia ciconia, Vanellus vanellus, Tringa totanus, Chlidonias niger and Falco subbuteo) and were typically carnivorous/insectivorous and migratory. Our findings correspond with documented declines (1990–2015) in insectivorous birds in Denmark and Europe (Bowler et al. 2019), with insect declines proposed as a contributing factor (Tallamy & Shriver 2021). Most carnivorous/insectivorous breeding birds in northern Europe are also migrants, making it hard to separate the effects of a migration from diet on population change. Like us, Bowler et al. (2019) also found a link between long-distance migrants and insectivores, hampering conclusions about whether migration habit or diet may be the ultimate driver of declines.

Our results show some congruence in plant, butterfly, and bird diversity changes despite differences in mobility and resource needs. Similar patterns have been observed in other studies linking farmland configuration to species richness across taxonomic groups (birds, spiders, butterflies, hares) (e.g., Šálek et al. 2018). The loss of plant, butterfly and bird species over the last 100–180 years is not unique to Denmark. Recent analyses indicate 19% of red-listed species in Europe are threatened with extinction, with plants and invertebrates at higher risk due to agricultural land-use changes (Hochkirch et al. 2023). Specialist species are lost more often than generalists, leading to both taxonomic and functional biodiversity homogenization (Clavel et al. 2011). The loss of large-scale natural processes supporting landscape and habitat heterogeneity e.g., hydrology, coastal dynamics, and grazing has had devastating effects on biodiversity (Perino et al. 2019; Svenning 2020). Restoring these processes (rewilding) can enhance ecological variation and biodiversity (Vera 2010).

Informed targets for conservation and ecological restoration

High-quality data series rarely extend back more than a few decades, so historical data from diary notes and collections were used to illustrate biodiversity loss over the last 180 years. The early 19th -century starting point and focus on plants, butterflies, and birds were dictated by data availability, not lack of relevance of earlier time periods or other taxonomic groups. We consider it certain that our study period is suboptimal, as many species were also vanishing prior to our starting point, leading to an underestimation of biodiversity loss (Mihoub et al. 2017). Some species may have benefitted from human intervention in historical landscapes, occurring in densities exceeding pre-agricultural levels (Szabo 2014). Linking species data with environmental changes is further complicated by extinction debt, or species’ lag in response to changes, potentially extending beyond 100 years (Bulman et al. 2007; Sand-Jensen et al. 2017). For example, butterfly loss associated with forest glades is visible in our data, but the cause dates back to changed forestry practices in 1805 or shortly thereafter. Likewise, there is a discrepancy between lost species and current habitat protection. For example, Carterocephalus Palaemon and Parnassius mnemosyne are listed in the Habitat Directive, but they were already eradicated from Denmark when the Habitat Directive was adopted. Hence, it is up to other countries to ensure their populations and create suitable habitats for them. However, we should use historical data to ensure habitats for species that historically lived here. While historical baselines have limitations (Douda et al. 2023), evolutionary baselines of pre-human conditions may be more relevant for restoring self-sustaining ecosystems, though challenged by data-deficiencies. Paleoecological evidence suggests that pre-agricultural Holocene (around 11,700–10,000 years ago) landscapes in Europe were mostly forested with significant glades and pasture-woodlands, indicating high forest heterogeneity. Disturbance by large herbivores played a crucial role in maintaining habitats for a wide range of species (Svenning 2002), although perhaps at reduced levels compared to the Pleistocene where pre-human landscapes had open and semi-open areas throughout as an effect of megafauna impacts (Pearce et al. 2023). Our historical reference indicates that some of these ecosystem features, such as grazing, habitat mosaic and openness may have been somewhat preserved in 18th century landscapes, supporting biodiversity.

Implications

The advent of the EU Restoration Law highlights the importance of international biodiversity references. Using a historical or evolutionary reference help setting targets for biotic integrity (Vačkář et al. 2012; Plumptre et al. 2021) and for habitat-generating ecosystem processes (Rouget et al. 2006), respectively, and provide relevant targets for evaluating restoration success. The process of compiling empirical evidence on biodiversity responses to reestablishing natural processes is ongoing, but we still have much to learn, e.g. species’ true habitat requirements.

Declaration of Competing Interest

The authors have no conflicts of interest to declare that are relevant to the content of this article.

Funding

This work was supported by 15. Juni Fonden (grant number 2021 − 0371)

Author Contribution

AKB, KKC, RE, CF, HHB, conceived and designed the research; AKB, EBB, HHB collated the data; AKB, KKC analyzed the data; AKB led the data analysis and wrote the major part of the manuscript; all authors contributed to writing and editing the manuscript.

Acknowledgement

We thank Lasse Dümke for entering parts of the historical plant data and Prof. Ingolf Kühn for providing the Biolflor data on plant habitat affinity.

Data Availability

Data will be made available on request.

Andersen AH, Clausen KK, Normand S, Vikstrøm T, Moeslund JE (2023) The influence of landscape characteristics on breeding bird dark diversity. Oecologia 201:1039–1052
Andersen DK, Nygaard B, Fredshavn JR, Ejrnæs R (2013) Cost-effective assessment of conservation status of fens. Appl Veg Sci 16:491–501
Bjerregård EB, Baastrup-Spohr L, Markussen B, Bruun HH (2023) Rapid and continuing regional decline of butterflies in eastern Denmark 1993–2019. Biol Conserv 284:110208
Bowler DE, Heldbjerg H, Fox AD, De Jong M, Böhning-Gaese K (2019) Long-term declines of European insectivorous bird populations and potential causes. Conserv Biol 33:1120–1130
Brunbjerg AK, Bruun HH, Dalby L, Fløjgaard C, Frøslev TG, Høye TT, Goldberg I, Læssøe T, Hansen MDD, Brøndum L, Skipper L, Fog K, Ejrnæs R (2018) Vascular plant species richness and bioindication predict multi-taxon species richness. Methods Ecol Evol 9:2372–2382
Bubová T, Vrabec V, Kulma M, Nowicki P (2015) Land management impacts on European butterflies of conservation concern: a review. J Insect Conserv 19:805–821
Bulman CR, Wilson RJ, Holt AR, Bravo LG, Early RI, Warren MS, Thomas CD (2007) Minimum viable metapopulation size, extinction debt, and the conservation of a declining species. Ecol Appl 17:1460–1473
Castaño-Villa GJ, Estevez JV, Guevara G, Bohada-Murillo M, Fontúrbel FE (2019) Differential effects of forestry plantations on bird diversity: A global assessment. For Ecol Manag 440:202–207
Clavel J, Julliard R, Devictor V (2011) Worldwide decline of specialist species: toward a global functional homogenization? Front Ecol Environ 9:222–228
Cooke SJ, Rous AM, Donaldson LA, Taylor JJ, Rytwinski T, Prior KA, Smokorowski KE, Bennett JR (2018) Evidence-based restoration in the Anthropocene—from acting with purpose to acting for impact. Restor Ecol 26:201–205
Crutzen PJ (2002) Geology of mankind. Nature 415:23–23
Dam P (2023) Integrating time and space in a digital-historical administrative atlas. Pages 185–204. In: Petrulevich A, Boeck SS (eds) Digital Spatial Infrastructures and Worldviews in Pre-Modern Societies. Arc Humanities
Davison CW, Rahbek C, Morueta-Holme N (2021) Land-use change and biodiversity: Challenges for assembling evidence on the greatest threat to nature. Glob Change Biol 27:5414–5429
Dolman PM (2012) Mechanisms and processes underlying landscape structure effects on bird populations. Birds and habitat: relationships in changing landscapes:93–124
Donald PF, Green RE, Heath MF (2001) Agricultural intensification and the collapse of Europe's farmland bird populations. Proceedings of the Royal Society of London. Series B: Biological Sciences 268:25–29
Douda J, Doudová J, Holeštová A, Chudomelová M, Vild O, Boublík K, Černá M, Havrdová A, Petřík P, Pychová N, Smyčková M, Šebesta J, Vaníček J, Hédl R (2023) Historical sampling error: A neglected factor in long-term biodiversity change research. Biol Conserv 286:110317
Eea (2020) State of nature in the EU. Results from reporting under the nature directives 2013–2018, Technical report No 10/2020, European Environment Agency, Copenhagen
Ejrnæs R, Bladt J, Dalby L, Pedersen PBM, Fløjgaard C, Levin G, Baaner L, Brunbjerg AK, Mellerup K, Angelidis I, Nygaard B (2021) Udvikling af en dansk naturindikator (DNI). Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, p 460
Ejrnæs R, Bruun HH (2000) Gradient analysis of dry grassland vegetation in Denmark. J Veg Sci 11:573–584
Eriksson O, Cousins SaO, Bruun HH (2002) Land-use history and fragmentation of traditionally managed grasslands in Scandinavia. J Veg Sci 13:743–748
Eskildsen A, Carvalheiro LG, Kissling WD, Biesmeijer JC, Schweiger O, Høye TT (2015) Ecological specialization matters: long-term trends in butterfly species richness and assemblage composition depend on multiple functional traits. Divers Distrib 21:792–802
Finderup Nielsen T, Sand-Jensen K, Bruun HH (2021) Drier, darker and more fertile: 140 years of plant habitat change driven by land-use intensification. J Veg Sci 32:e13066
Finderup Nielsen T, Sand-Jensen K, Dornelas M, Bruun HH (2019) More is less: net gain in species richness, but biotic homogenization over 140 years. Ecol Lett 22:1650–1657
Fredshavn J, Ejrnæs R, Nygaard B (2010) Teknisk anvisning for kortlægning af terrestriske naturtyper. TA-N3, Version 1.04. Fagdatacenter for Biodiversitet og Terrestriske Naturdata, Danmarks Miljøundersøgelser
Gregory RD, Vořišek P, Noble DG, Van Strien A, Klvaňová A, Eaton M, Gmelig Meyling AW, Joys A, Foppen RPB, Burfield IJ (2008) The generation and use of bird population indicators in Europe. Bird Conserv Int 18:S223–S244
Grime JP, Hodgson JG, Hunt R (1989) Comparative plant ecology: a functional approach to common British species. Unwin Hyman, London
Habel JC, Schmitt T, Ulrich W, Gros P, Salcher B, Teucher M (2023) Landscape homogenisation and simplified butterfly community structure go on par across Northern Austria. Landscape Ecol 38:3237–3248
Habel JC, Segerer A, Ulrich W, Torchyk O, Weisser WW, Schmitt T (2016) Butterfly community shifts over two centuries. Conserv Biol 30:754–762
Habel JC, Trusch R, Schmitt T, Ochse M, Ulrich W (2019) Long-term large-scale decline in relative abundances of butterfly and burnet moth species across south-western Germany. Sci Rep 9:14921
Hartvig P (2015) Atlas Flora Danica. Bind 2, 3: Artsoversigt/udbredelse. Gyldendal, Copenhagen
Heldbjerg H, Sunde P, Fox AD (2018) Continuous population declines for specialist farmland birds 1987–2014 in Denmark indicates no halt in biodiversity loss in agricultural habitats. Bird Conserv Int 28:278–292
Hill MO, Mountford JO, Roy DB, Bunce RGH (1999) Ellenberg's indicator values for British plants: ECOFACT volume, vol 2. Technical Annex. Centre for Ecology and Hydrology, Natural Environment Research Council
Hochkirch A, Bilz M, Ferreira CC, Danielczak A, Allen D, Nieto A, Rondinini C, Harding K, Hilton-Taylor C, Pollock CM, Seddon M, Vié J-C, Alexander KNA, Beech E, Biscoito M, Braud Y, Burfield IJ, Buzzetti FM, Cálix M, Carpenter KE, Chao NL, Chobanov D, Christenhusz MJM, Collette BB, Comeros-Raynal MT, Cox N, Craig M, Cuttelod A, Darwall WRT, Dodelin B, Dulvy NK, Englefield E, Fay MF, Fettes N, Freyhof J, García S, Criado MG, Harvey M, Hodgetts N, Ieronymidou C, Kalkman VJ, Kell SP, Kemp J, Khela S, Lansdown RV, Lawson JM, Leaman DJ, Brehm JM, Maxted N, Miller RM, Neubert E, Odé B, Pollard D, Pollom R, Pople R, Presa Asensio JJ, Ralph GM, Rankou H, Rivers M, Roberts SPM, Russell B, Sennikov A, Soldati F, Staneva A, Stump E, Symes A, Telnov D, Temple H, Terry A, Timoshyna A, Swaay CV, Väre H, Walls RHL, Willemse L, Wilson B, Window J, Wright EGE, Zuna-Kratky T (2023) A multi-taxon analysis of European Red Lists reveals major threats to biodiversity. PLoS ONE 18:e0293083
Ipbes, ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (2019) Global assessment report on biodiversity and. E. S. Brondizio, J. Settele, S. Díaz, and H. T. Ngo (editors). IPBES secretariat, Bonn, Germany. 1148 pages. https://doi.org/10.5281/zenodo.3831673
Johnson CN, Balmford A, Brook BW, Buettel JC, Galetti M, Guangchun L, Wilmshurst JM (2017) Biodiversity losses and conservation responses in the Anthropocene. Science 356:270–275
Klein ES, Thurstan RH (eds) (2016) Acknowledging Long-Term Ecological Change: The Problem of Shifting Baselines. Pages 11–29 In: Schwerdtner Máñez K and Poulsen B, (eds) Perspectives on Oceans Past. Springer Netherlands, Dordrecht
Kühn I, Durka W, Klotz S (2004) BiolFlor — a new plant-trait database as a tool for plant invasion ecology. Divers Distrib 10:363–365
Legendre P, and Legendre L (1998) Numerical ecology. Elsevier, New York
Levin G (2022) Basemap04. Documentation of the data and method for elaboration of a land use and land cover map for Denmark. Aarhus University, DCE – Danish Centre for Environment and Energy, 77 pp. Technical Report No. 252 http://dce2.au.dk/pub/TR252.pdf
Levin G, Normander B (2008) Arealanvendelse i Danmark siden slutningen af 1800-tallet. Danmarks Miljøundersøgelser, Aarhus Universitet. Faglig rapport fra DMU nr. 682
Lohrum N, Normand S, Dalgaard T, Graversgaard M (2024) Unveiling the frontiers: Historical expansion and modern implications of agricultural land use in Denmark. J Environ Manage 359:120934
Meltofte H, Dinesen L, Boertmann D, Hald-Mortensen P (2021) Danmarks fugle gennem to århundreder. Dansk Ornitologisk Forenings Tidsskrift 115:1–184
Mihoub J-B, Henle K, Titeux N, Brotons L, Brummitt NA, Schmeller DS (2017) Setting temporal baselines for biodiversity: the limits of available monitoring data for capturing the full impact of anthropogenic pressures. Sci Rep 7:41591
Newbold T, Bentley LF, Hill SLL, Edgar MJ, Horton M, Su G, Şekercioğlu ÇH, Collen B, Purvis A (2020) Global effects of land use on biodiversity differ among functional groups. Funct Ecol 34:684–693
Oksanen J, Blanchet FG, Kindt R, Legendre P, O'hara RB, Simpson GL, Solymos P, Stevens MHH, Wagner H (2017) Package 'vegan': Community Ecology Package. Version 2.4-3. http://cran.r-project.org/web/packages/vegan/vegan.pdf
Papworth SK, Rist J, Coad L, Milner-Gulland EJ (2009) Evidence for shifting baseline syndrome in conservation. Conserv Lett 2:93–100
Pearce EA, Mazier F, Normand S, Fyfe R, Andrieu V, Bakels C, Balwierz Z, Bińka K, Boreham S, Borisova OK, Brostrom A, De Beaulieu J-L, Gao C, González-Sampériz P, Granoszewski W, Hrynowiecka A, Kołaczek P, Kuneš P, Magri D, Malkiewicz M, Mighall T, Milner AM, Möller P, Nita M, Noryśkiewicz B, Pidek IA, Reille M, Robertsson A-M, Salonen JS, Schläfli P, Schokker J, Scussolini P, Šeirienė V, Strahl J, Urban B, Winter H, Svenning J-C (2023) Substantial light woodland and open vegetation characterized the temperate forest biome before Homo sapiens. Sci Adv 9:eadi9135
Perino A, Pereira HM, Navarro LM, Fernández N, Bullock JM, Ceaușu S, Cortés-Avizanda A, Van Klink R, Kuemmerle T, Lomba A, Pe’er G, Plieninger T, Rey Benayas JM, Sandom CJ, Svenning J-C, Wheeler HC (2019) Rewilding complex ecosystems. Science 364:eaav5570
Plumptre AJ, Baisero D, Belote RT, Vázquez-Domínguez E, Faurby S, Jȩdrzejewski W, Kiara H, Kühl H, Benítez-López A, and Luna-, Aranguré C (2021) Where might we find ecologically intact communities? Frontiers in Forests and Global Change 4:626635
R Core Team (2022) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria
Rouget M, Cowling RM, Vlok JN, Thompson M, Balmford A (2006) Getting the biodiversity intactness index right: the importance of habitat degradation data. Glob Change Biol 12:2032–2036
Šálek M, Hula V, Kipson M, Daňková R, Niedobová J, Gamero A (2018) Bringing diversity back to agriculture: Smaller fields and non-crop elements enhance biodiversity in intensively managed arable farmlands. Ecol Ind 90:65–73
Sand-Jensen K, Bruun HH, Baastrup-Spohr L (2017) Decade-long time delays in nutrient and plant species dynamics during eutrophication and re-oligotrophication of Lake Fure 1900–2015. J Ecol 105:690–700
Soga M, Gaston KJ (2018) Shifting baseline syndrome: causes, consequences, and implications. Front Ecol Environ 16:222–230
Stoltze M (1996) Danske dagsommerfugle, Gyldendalske boghandel. Nordisk Forlag A/S, Copenhagen
Streitberger M, Hermann G, Kraus W, Fartmann T (2012) Modern forest management and the decline of the Woodland Brown (Lopinga achine) in Central Europe. For Ecol Manag 269:239–248
Suding KN (2011) Toward an Era of Restoration in Ecology: Successes, Failures, and Opportunities Ahead. Annu Rev Ecol Evol Syst 42:465–487
Svenning J-C (2002) A review of natural vegetation openness in north-western Europe. Biol Conserv 104:133–148
Svenning J-C (2020) Rewilding should be central to global restoration efforts. One Earth 3:657–660
Szabo JK (2014) The skylark. Pages 351–372. Invasion Biology and Ecological Theory: Insights from a Continent in Transformation. Cambridge University Press
Tallamy DW, Shriver WG (2021) Are declines in insects and insectivorous birds related? Ornithological Appl 123:duaa059
Tobias JA, Sheard C, Pigot AL, Devenish AJM, Yang J, Sayol F, Neate-Clegg MHC, Alioravainen N, Weeks TL, Barber RA, Walkden PA, Macgregor HEA, Jones SEI, Vincent C, Phillips AG, Marples NM, Montaño-Centellas FA, Leandro-Silva V, Claramunt S, Darski B, Freeman BG, Bregman TP, Cooney CR, Hughes EC, Capp EJR, Varley ZK, Friedman NR, Korntheuer H, Corrales-Vargas A, Trisos CH, Weeks BC, Hanz DM, Töpfer T, Bravo GA, Remeš V, Nowak L, Carneiro LS, Moncada RAJ, Matysioková B, Baldassarre DT, Martínez-Salinas A, Wolfe JD, Chapman PM, Daly BG, Sorensen MC, Neu A, Ford MA, Mayhew RJ, Fabio Silveira L, Kelly DJ, Annorbah NND, Pollock HS, Grabowska-Zhang AM, Mcentee JP, Carlos T, Gonzalez J, Meneses CG, Muñoz MC, Powell LL, Jamie GA, Matthews TJ, Johnson O, Brito GRR, Zyskowski K, Crates R, Harvey MG, Jurado Zevallos M, Hosner PA, Bradfer-Lawrence T, Maley JM, Stiles FG, Lima HS, Provost KL, Chibesa M, Mashao M, Howard JT, Mlamba E, Chua MH, Li B, Gómez MI, García NC, Päckert M, Fuchs J, Ali JR, Derryberry EP, Carlson ML, Urriza RC, Brzeski KE, Prawiradilaga DM, Rayner MJ, Miller ET, Bowie RCK, Lafontaine R-M, Scofield RP, Lou Y, Somarathna L, Lepage D, Illif M, Neuschulz EL, Templin M, Dehling DM, Cooper JC, Pauwels OSG, Analuddin K, Fjeldså J, Seddon N, Sweet PR, Declerck FJ, Naka LN, Brawn JD, Aleixo A, Böhning-Gaese K, Rahbek C, Fritz SA, Thomas GH, Schleuning M (2022) AVONET: morphological, ecological and geographical data for all birds. Ecol Lett 25:581–597
Turvey ST, Crees JJ (2019) Extinction in the Anthropocene. Curr Biol 29:R982–R986
Tyler T, Herbertsson L, Olofsson J, Olsson PA (2021) Ecological indicator and traits values for Swedish vascular plants. Ecol Ind 120:106923
Vačkář D, Ten Brink B, Loh J, Baillie JEM, Reyers B (2012) Review of multispecies indices for monitoring human impacts on biodiversity. Ecol Ind 17:58–67
Van Swaay CM, Nowicki P, Settele J, Van Strien AJ (2008) Butterfly monitoring in Europe: methods, applications and perspectives. Biodivers Conserv 17:3455–3469
Vera F (2010) The shifting baseline syndrome in restoration ecology. Pages 116–128 In: Restoration and history. Routledge
Warren MS, Maes D, Van Swaay CM, Goffart P, Van Dyck H, Bourn ND, Wynhoff I, Hoare D, Ellis S (2021) The decline of butterflies in Europe: Problems, significance, and possible solutions. Proceedings of the National Academy of Sciences 118:e2002551117
Wilcoxon F (1945) Individual comparisons by ranking methods. Biometrics 1:80–83

Table 1 Mantel test results from the analyses on species change (historical (1900-1049) and current (2000-2019) species composition) and environmental variables in the 9 butterfly localities. Variation (R²) in species dissimilarity explained by dissimilarity in environmental variables (Ellenberg L (Ell_L), Ellenberg F (Ell_F), Ellenberg N (Ell_N), Ellenberg R (Ell_R), Grime S, Grime R, Grime C, habitat type diversity (BiolflorClass) and plant species richness (plant spc rich)). P-values are given (1000 permutations).

Mantel	R²	P
Species change ~ Ell_L	0.13 %	0.607
Species change ~ Ell_F	0.02 %	0.559
Species change ~ Ell_N	10.60 %	0.006
Species change ~ Ell_R	1.80 %	0.105
Species change ~ Grime S	14.62 %	0.002
Species change ~ Grime R	0.75 %	0.775
Species change ~ Grime C	1.91 %	0.069
Species change ~ BiolflorClass	1.13 %	0.172
Species change ~ plant spc rich	0.02 %	0.429

No competing interests reported.

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Using centennial changes in plant, butterfly and bird diversity to inform restoration targets

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Abstract

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Introduction

Methods

Results

Plants

Butterflies

Birds

Land-use changes

Discussion

Centennial changes in landscape, plant, butterfly and bird diversity

Informed targets for conservation and ecological restoration

Implications

Declarations

Declaration of Competing Interest

Funding

Author Contribution

Acknowledgement

Data Availability

References

Tables

Additional Declarations

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