Agricultural activities and their complex effects on nature conservation, and the services that ecosystems deliver to humans are controversial. We present an overview of land abandonment, its driving forces and its consequences for landscape, biodiversity and humans. A descriptive metaanalysis of independently published studies highlighted the fact that the abandonment of agricultural land is a phenomenon mostly driven by socio-economic factors such as immigration into areas where new economic opportunities are offered to rural people. Ecological drivers such as elevation and land mismanagement leading to soil erosion are of secondary importance. We identified the major problems related to abandonment of agricultural land and quantified their relative importance. In order of decreasing importance, they were biodiversity loss, increase of fire frequency and intensity, soil erosion and desertification, loss of cultural and/or aesthetic values, reduction of landscape diversity and reduction of water provision. The impacts of these problems were not equally relevant in all regions of the world. The abandonment of agricultural land may also benefit humans. The benefits include passive revegetation and active reforestation, water regulation, soil recovery, nutrient cycling and increased biodiversity and wilderness. In a world that is becoming less natural and more intensively exploited by humans, we suggest that (1) farmland must be viewed in a context of multi-functionality to take advantage of ecosystem goods and services, (2) at the global scale, the abandonment of agricultural land is mostly positive for humans and (3) there is a need for the implementation of policies based on the payments for environmental services that encourage human societies to reconcile agricultural use, nature conservation and ecological restoration.

/pdf/abandonment-of-agricultural-land-an-overview-of-drivers-and-3ajrzs3n4o.pdf

Abandonment of agricultural land: an overview of drivers and consequences

This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects. Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of disturbance, total community biomass, colonization, the species pool and spatial heterogeneity. The structure of the model leads to two main expectations: (1) while community biomass is important, multivariate approaches will be required to understand patterns of variation in species density, and (2) species density will be more highly correlated with light penetration to the soil surface, than with above-ground biomass, and even less well correlated with plant growth rates (productivity) or habitat fertility. At present, data are insufficient to evaluate the relative importance of the processes controlling species density. Much more work is needed if we are to adequately predict the effects of environmental changes on plant communities and species diversity.

The factors controlling species density in herbaceous plant communities: an assessment

https://ibot.sav.sk/usr/Monika/docs/PDF_files/Dengler_et_al_2014_AGEE.pdf

Biodiversity of Palaearctic grasslands: a synthesis

Changing land use and its impact on biodiversity

Summary


Recent declines in biodiversity have given new urgency to questions about the relationship between land-use change, biodiversity and ecosystem processes. Despite the existence of a large body of research on the effects of land use on species richness, it is unclear whether the effects of land use on species richness are principally direct or indirect, mediated by concomitant changes in ecosystem processes. Therefore, we compared the direct effects of land use (fertilization, mowing and grazing) on species richness with indirect ones (mediated via grassland productivity) for grasslands in central Europe.
We measured the richness and above-ground biomass in 150 grassland plots in 3 regions of Germany (the so-called Biodiversity Exploratories). We used univariate and structural equation models to examine direct and indirect land-use effects.
The direct effects of mowing (−0.37, effect size) and grazing (0.04) intensity on species richness were stronger compared with the indirect effects of mowing (−0.04) and grazing (−0.01). However, the strong negative effect of fertilization (−0.23) on species richness was mainly indirect, mediated by increased productivity compared with the weak direct negative effect (−0.07).
Differences between regions in land-use effects showed five times weaker negative effects of mowing (−0.13) in the region with organic soils (Schorfheide-Chorin), strong overall negative effects of grazing (−0.29) for the region with organic soils opposed to a similar strong positive effect (0.30) in the Hainich-Dun region, whereas the Schwabische Alb region displayed a five times weaker positive effect (0.06) only. Further, fertilization effects on species richness were positive (0.03) for the region with organic soils compared to up to 25 times stronger negative effects in the other two regions.
Synthesis. Our results clearly show the importance of studying both direct and indirect effects of land-use intensity. They demonstrate the indirect nature, via productivity, of the negative effect of fertilization intensity on plant species richness in the real-world context of management-induced gradients of intensity of fertilization, mowing and grazing. Finally, they highlight that careful consideration of regional environments is necessary before attempting to generalize land-use effects on species diversity.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2745.2012.02020.x

Direct and productivity-mediated indirect effects of fertilization, mowing and grazing on grassland species richness

An experiment was established to assess the long-term effects of six different management types on the species composition of dry limestone grasslands with the aim of finding an alternative to the traditional management (mowing annually in July) which is no longer economically viable. In addition to the traditional management (JU1), the following management types were applied experimentally for 22 years: mowing every 2 years in July (JU2), every 5 years (JU5), or not at all (ABN, abandonment), mowing annually in October (OCT), and controlled burning annually (CBR) at the end of winter. There were two study sites, Grate and Gratental, near Schaffhausen in N Switzerland, each with three replicate 5 m×10 m plots for every management. During the course of the experiment, the vegetation was recorded on 10 occasions, yielding 306 vegetation releves containing a total of 124 species. These data were analysed using correspondence analyses (CA). In addition, changes in the abundance of 16 plant species with high cover, high frequency or particular importance for nature conservation were examined in detail. The CA showed that the vegetation of the two study sites differed considerably, but that in both sites the various management types led to changes in floristic composition which were probably continuing even after 22 years. At the end of the experiment, on the Grate site, species number in comparison to JU1 had declined in the following progressive order: OCT, JU2, JU5, CBR, ABN, where it was down to 70%. At the Gratental site, species number showed no clear pattern, because of the immigration of ‘new’ species from the surrounding hedges and agricultural fields. Interestingly, Bromus erectus , the dominant species with a cover of 40–70% at the beginning, decreased to 5–30% under different managements, mainly because the regeneration of its tufts is affected by abandonment and particularly burning. The rhizomatous Brachypodium pinnatum showed the opposite pattern and increased from 5% to 60% in CBR. Trifolium medium as well as Salvia pratensis , Primula veris and other long-lived forbs of high conservation value tended to be favoured by OCT, CBR and/or ABN because they can store nutrients if they are not annually cut in July. On the other hand, several low growing species like Anthyllis vulneraria and Hieracium pilosella need the better light conditions associated with the annual mowing in July for optimal growth. In every management type, some species of high conservation value decreased whereas others increased! According to our results, the best strategy—for achieving and maintaining a high species diversity—is a mosaic of different management types, i.e. a central part of the grassland managed traditionally, i.e. mown annually in July, and large strips at the margins mown only every second year in July or October. When mown in October, the soil has to be nutrient-poor and the site isolated from the seed rain of forest fringe species, which otherwise could become dominant and lead to a decline in species. The alternative of mowing the whole area every second year in July or annually in October (with the same restrictions for mowing in October) it is not completely satisfactory because several species may be lost in the long term.

Changes in the species composition and conservation value of limestone grasslands in Northern Switzerland after 22 years of contrasting managements

Species richness, species composition and standing crop were studied in a limestone grassland in northern Switzerland after 13 and 15 years of experimental management with 6 management regimes differing in form, time and frequency of biomass removal. The management regimes with a cut at least every 2nd year had a higher species number per 40 m2 and 1 m2 than those cut less frequently, abandoned or annually burned. Annual burning and a cut every 5th year lead to a similar decrease in species richness as abandonment. Differences in species richness between different regimes increased with increasing spatial resolution of observation. Many species occurred in a plot during only one of the two sample years. This turnover of species was the highest in plots with the lowest species numbers, and increased with increasing spatial resolution. Standing crop was highest in plots burned annually (290 g m−2), and lowest in plots cut annually in July (1989 g m−2). Standing crop and litter increased with decreasing frequency of cutting. *** DIRECT SUPPORT *** A02DO006 00005

Species richness and vegetation structure in a limestone grassland after 15 years management with six biomass removal regimes

To counter the often depressing information contained in Red Lists and similar lists of threatened species, we propose the use of Blue Lists that enumerate those red-list species experiencing lasting overall stabilization or an increase in abundance in the region considered. Blue lists are (mostly) a subset of the Red Lists. We defined three main categories for blue-listed species: (1) those whose increases merit delisting from the Red List; (2) those increasing in abundance, but not enough to warrant delisting; and (3) those whose abundance is stable. Remaining categories outside the Blue List include (1) decrease; (2) ( local) extinction; and (3) change in abundance unknown. For practical use, information on conservation or recovery techniques necessary for maintaining or promoting the species could be added to the lists. In a test region of 3431 km2 in northern Switzerland, representative of hilly and densely populated areas in central Europe, we enumerated Blue Lists for 122 species of all the vertebrate classes and 722 vascular plant species, all of which are on the regional Red Lists. Large differences exist between these systematic groups in the proportions of species in the different categories. Overall, Blue Lists comprise approximately one-third of the red-listed species considered. For a further 50%, nature conservation techniques for maintenance or promotion are known but have not yet been applied effectively. If all known techniques were applied to a greater extent, the persistent decline of most of the species in the region could be stopped or reversed. We discuss the scientific and psychological weaknesses and strengths of the Blue Lists. They can strengthen public motivation for conservation and advance self-confidence among conservationists by quantifying and stressing successes in species conservation, by giving this positive information an identity, by showing promising possibilities for action, and by providing a useful public relations tool. The Blue List concept can also be applied to species covered by the U.S. Endangered Species Act and by The Nature Conservancy's ranking system on the global, national, or regional scale.




Resumen: Para contrapesar la informacion, a menudo deprimente, incluida en las Listas Rojas y otras listas de especies amenazadas, se ha desarrollado un instrumento nuevo: las Listas Azules, es decir registros de aquellas especies de las Listas Rojas que muestran una estabilizacion duradera o un aumento en abundancia en la region considerada. Las Listas Azules son (en gran medida) un subconjunto de las Listas Rojas. Definimos tres categorias principales para las especies de las Listas Azules: (1) aquellas que por sus incrementos merecen ser retiradas de las Listas Rojas; (2) aquellas cuya abundancia esta en aumento, pero no lo suficiente como para justificar que se retiren de las listas; y (3) aquellas que tienen una abundancia estable. Las categorias adicionales que no pertenecen a la Lista Azul son: (1) disminucion; (2) extincion ( local) y (3) cambio desconocido en la abundancia. Para aplicaciones practicas es ventajoso anadir a las Listas Azules la informacion sobre las tecnicas de conservacion necesarias para el mantenimiento o la promocion de las especies. En una region de prueba en el norte de Suiza de 3431 km2, representativa de las areas montanosas y densamente pobladas de Europa central, enumeramos Listas Azules para 122 especies de todas las clases de vertebrados y 722 especies de plantas vasculares, todas ellas incluidas en Listas Rojas regionales. Existen grandes diferencias entre los grupos sistematicos en las proporciones de especies en las diversas categorias. En total, las Listas Azules abarcan aproximadamente un tercio de las especies de las Listas Rojas consideradas. Para otro 50% se conocen las tecnicas de conservacion para su mantenimiento o promocion, pero todavia no han sido aplicadas de manera eficaz. Si se aplicaran todas las tecnicas conocidas a mayor escala, la disminucion continua de la mayoria de las especies en la region se podria detener o revertir. Discutimos las cualidades y debilidades tanto cientificas como psicologicas de las Listas Azules. Pueden contribuir a reforzar la motivacion del publico para la conservacion y pueden promover la confianza en si mismos entre los conservacionistas al cuantificar y hacer notar los exitos en la conservacion de especies, al mostrar las posibilidades prometedoras de accion y al proveer una herramienta util en las relaciones publicas. El concepto de las Listas Azules se puede aplicar tambien a las listas del Acta de las Especies Amenazadas de los Estados Unidos, asi como al sistema de clasificacion de The Nature Conservancy a escala global, nacional, o regional.

Blue Lists of Threatened Species with Stabilized or Increasing Abundance: a New Instrument for Conservation

. In order to stress successes in restoration and conservation of species, regionally, nationally or globally, a new instrument has been developed, the ‘Blue Lists’, ‘registers of those Red List species that show a durable overall stabilization or increase of abundance in the region (nation, world) considered’. ‘Blue Data Books’ include additional information on the ecology, conservation, and promotion of the species. For describing the overall change of abundance of every individual species six categories are defined. Furthermore, the effects of nature conservation techniques (NCT) on a species are evaluated using six additional categories. In a test area of 3 431 km2 in northern Switzerland, information was compiled on the change in abundance of the 708 Red List species of higher plants (spermatophyta) over the last 10-15 yr. Overall, 33% of these species showed a stabilization or even increase in abundance; these are Blue List species; ca.20% showed a decline and for almost 50% the change in abundance is not known. NCTs have been successfully applied to more than 50 % of all the species, at least locally. For about a further 30%, the required NCTs are known but have not yet been tried out. If these techniques were applied on a large scale, the decline of very many species in the test area could be stopped.

Blue Data Books ‐ an encouraging new instrument for restoration and conservation

Ein wichtiges und seit langem bewahrtes Instrument im Naturschutz sind die Roten Listen der gefahrdeten oder ausgestorbenen Arten. Allerdings vermitteln sie ein dusteres Bild, da sie meist immer langer werden. Zusammen mit vielen anderen negativen Meldungen aus dem Naturschutz sowie den geforderten Einschrankungen und Verboten wirkt dies fur viele Menschen auf die Dauer entmutigend. Auch fragen sich manche, was denn der zumindest in Westeuropa betrachtliche finanzielle Einsatz fur den Naturschutz gebracht hat, wenn die Roten Listen immer langer werden und die Naturschutzprobleme kaum abnehmen. Erfolgsmeldungen sind in der wissenschaftlichen Literatur dunn gesat bzw. in internen, nicht publizierten Berichten von Naturschutzfachstellen weit verstreut. Deshalb haben diese Meldungen in der Naturschutz-Diskussion und in der Offentlichkeit kaum eine Wirkung. Um eine Anerkennung und einen Public-Relations-Wert der Naturschutzerfolge zu erreichen und dadurch die Motivation der Offentlichkeit sowie der Entscheidungstrager fur den Schutz der Natur zu erhohen, wurden zwischen 1993 und 1998 die Blauen Listen erarbeitet. Dabei wurde folgendermasen vorgegangen: 1. Erarbeitung einer standardisierten, wissenschaftlichen Methode, um die Stabilisierung oder Vergroserung des Bestandes (Haufigkeit bzw. Areal) von Rote-Liste-Arten zu erfassen. 2. Beschreibung der Natur- und Umweltschutztechniken, die zur Stabilisierung oder Vergroserung des Bestandes der Arten gefuhrt haben oder fuhren konnten. 3. Erprobung des neuen Instrumentes in der nordlichen Schweiz. Im Folgenden wird eine kurze Zusammenfassung und Diskussion des Konzeptes der Blauen Listen und ihrer Anwendung in der nordlichen Schweiz gegeben.


Keywords:

ausgestorbene Arten;
bedrohte Arten;
Bestandsstabilisierung;
Blaue Listen;
CITES Listen;
gefahrdete Arten;
Orchideen;
Passeriformes;
Rote Liste;
Species of European Conservation Concern;
SPEC-Listen;
Sperlingsvogel

/pdf/blaue-listen-der-erfolgreich-geforderten-bedrohten-arten-ein-43la58s3ze.pdf

Regula Langenauer

Papers

Changes in the species composition and conservation value of limestone grasslands in Northern Switzerland after 22 years of contrasting managements

Species richness and vegetation structure in a limestone grassland after 15 years management with six biomass removal regimes

Blue Lists of Threatened Species with Stabilized or Increasing Abundance: a New Instrument for Conservation

Blue Data Books ‐ an encouraging new instrument for restoration and conservation

Blaue Listen der erfolgreich geförderten bedrohten Arten – ein neues, ermutigendes Naturschutzinstrument