Land‐use effects on the functional distinctness of arthropod communities

Land‐use change is a major driver of the global loss of biodiversity, but it is unclear to what extent this also results in a loss of ecological traits. Therefore, a better understanding of how land‐use change affects ecological traits is crucial for efforts to sustain functional diversity. To this end we tested whether higher species richness or taxonomic distinctness generally leads to increased functional distinctness and whether intensive land use leads to functionally more narrow arthropod communities. We compiled species composition and trait data for 350 species of terrestrial arthropods (Araneae, Carabidae and Heteroptera) in different land‐use types (forests, grasslands and arable fields) of low and high land‐use intensity. We calculated the average functional and taxonomic distinctness and the rarified trait richness for each community. These measures reflect the range of traits, taxonomic relatedness and number of traits that are observed in local communities. Average functional distinctness only increased significantly with species richness in Carabidae communities. Functional distinctness increased significantly with taxonomic distinctness in communities of all analyzed taxa suggesting a high functional redundancy of taxonomically closely related species. Araneae and Heteroptera communities had the expected lower functional distinctness at sites with higher land‐use intensity. More frequently disturbed land‐use types such as managed grasslands or arable fields were characterized by species with smaller body sizes and higher dispersal abilities and communities with lower functional distinctness or trait richness. Simple recommendations about the conservation of functional distinctness of arthropod communities in the face of future land‐use intensification and species loss are not possible. Our study shows that these relationships depend on the studied taxa and land‐use type. However, for some arthropod groups functional distinctness is threatened by intensification and conversion from less to more frequently disturbed land‐uses.     

Low-Intensity Agricultural Landscapes in Transylvania Support High Butterfly Diversity: Implications for Conservation

European farmland biodiversity is declining due to land use changes towards agricultural intensification or abandonment. Some Eastern European farming systems have sustained traditional forms of use, resulting in high levels of biodiversity. However, global markets and international policies now imply rapid and major changes to these systems. To effectively protect farmland biodiversity, understanding landscape features which underpin species diversity is crucial. Focusing on butterflies, we addressed this question for a cultural-historic landscape in Southern Transylvania, Romania. Following a natural experiment, we randomly selected 120 survey sites in farmland, 60 each in grassland and arable land. We surveyed butterfly species richness and abundance by walking transects with four repeats in summer 2012. We analysed species composition using Detrended Correspondence Analysis. We modelled species richness, richness of functional groups, and abundance of selected species in response to topography, woody vegetation cover and heterogeneity at three spatial scales, using generalised linear mixed effects models. Species composition widely overlapped in grassland and arable land. Composition changed along gradients of heterogeneity at local and context scales, and of woody vegetation cover at context and landscape scales. The effect of local heterogeneity on species richness was positive in arable land, but negative in grassland. Plant species richness, and structural and topographic conditions at multiple scales explained species richness, richness of functional groups and species abundances. Our study revealed high conservation value of both grassland and arable land in low-intensity Eastern European farmland. Besides grassland, also heterogeneous arable land provides important habitat for butterflies. While butterfly diversity in arable land benefits from heterogeneity by small-scale structures, grasslands should be protected from fragmentation to provide sufficiently large areas for butterflies. These findings have important implications for EU agricultural and conservation policy. Most importantly, conservation management needs to consider entire landscapes, and implement appropriate measures at multiple spatial scales.     

Changes in land use and habitat availability affect the population genetic structure of Metrioptera roeselii (Orthoptera: Tettigoniidae)

The impact of temporal changes in habitat availability and land use on the present genetic diversity of the grassland katydid species Metrioptera roeselii was investigated in an extensively used agricultural landscape (Lahn-Dill-Bergland, Germany) based on six microsatellite loci. By integrating spatial and temporal dimensions, this study contrasts to conventional approaches that usually record landscape changes at discrete points in time. Molecular data suggest little geographical substructuring of the species. Nevertheless, time-dependent effects on genetic diversity in terms of observed heterozygosity and allelic richness within subpopulations were detected by general linear models (GLM), explaining up to 82 and 13%, respectively. The results indicated that allelic richness was significantly reduced with higher rates of land-use change. Contrastingly, the level of heterozygosity even increased with increasing land-use change, if this rate increase was accompanied by a reduction in grassland amount, while with an increase of grassland amount the level of heterozygosity remained similar. Furthermore, depending on the study site, heterozygosity was differently affected by grassland age of sampled patches and of the surrounding. This is presumably induced by contrasting levels of heterozygosity in combination with differing modes of dispersal due to habitat availability and site-specific matrix effects. The loss of genetic diversity due to frequent land-use change might result in a reduced ability to adapt to landscape change, which is even more relevant in intensively used agricultural landscapes and in the course of climate change.     

The significance of habitat continuity and current management on the compositional and functional diversity of grasslands in the uplands of Lower Saxony,Germany

There is a growing concern that land use intensification is having negative effects on semi-natural grasslands and that it leads to a general loss of biodiversity among all types of formerly extensively managed grasslands of poor to medium nutrient richness. Since the 1950s, many Central European uplands have been subject to an increase in grassland cover as a result of changes in land use practices. Using such a landscape in Lower Saxony, Germany, as a model region, we assessed environmental factors that control grassland diversity, including plant community composition, species richness and pollination trait composition. In 2007, 189 vegetation sampling sites were randomly distributed among grasslands covering some 394 ha within a 2500 ha study area. Plant communities were classified using TWINSPAN and the effects of environmental factors (soil, topography, current management and habitat continuity) were analysed by canonical correspondence analysis and regression analysis reducing for the effects of spatial autocorrelation by using principal coordinates of neighbour matrices.We found a wide range of six species-poor (<15 plant spp.) to extremely species-rich (>27 spp.) grassland types under mesic to dry site conditions, including sown, Cynosurion, Arrhenatherion and semi-natural grasslands. Grassland community composition was best explained by soil factors and species richness and pollination type composition by combined effects of current management and habitat continuity. During the 1950/60s, the extent of grassland area within the studied landscape rapidly increased to more than double its previous extent, and in 2007, grasslands comprised 16%. Natura 2000 grassland types comprised 1% of the surveyed site and medium-rich, high-nature-value grasslands a further 5%. While the number of wind-pollinated plant species was equal among all grassland types, there was a parallel decline in insect-pollinated plants and overall median species richness in the grassland communities along a gradient of increasing land use intensity (mowing, nutrient supply). Moreover, insect-pollinated plants occurring in intensively managed grasslands were found to additionally have the ability for self-pollination. Species-rich grasslands – including semi-natural grasslands and a semi-improved, species-rich Arrhenatherion community – occurred exclusively on old sites (with >100 years of habitat continuity) that had been used for traditional sheep grazing (environmental contracting). Medium-rich Arrhenatherion grasslands were established primarily on less productive, formerly arable fields (<30 years). We conclude that conservation efforts should focus on extant species-rich grassland types and should aim to implement traditional land use practices such as sheep grazing. Additional restoration efforts should focus on establishing new grasslands on less productive sites in the proximate surroundings of species-rich grasslands to facilitate seed dispersal, but nitrogen deposition should be buffered where appropriate. These measures would enhance the interaction between nature reserves and agricultural grasslands and thus improve the ecological quality of grasslands at the landscape scale.     

Effect of land-use heterogeneity on carabid communities at the landscape scale

Carabid beetle assemblages were studied to assess how diversity and community structure varied along a gradient of land-use. This gradient was composed of six 1 km² quadrats with an increasing proportion of agricultural land reflecting the anthropogenic fragmentation and intensification of landscapes. Carabid species richness and abundance was predicted to peak in the most heterogeneous landscape, in accord with the intermediate disturbance hypothesis (IDH), and then decline as agricultural intensification increased. It was also predicted that the different landscapes would support beetle communities distinct from each other. The IDH was unsupported-in both years of this study carabid species richness and abundance was greatest in the most intensively managed, agricultural sites. Detrended correspondence analysis revealed a clear separation in beetle community structure between forested and open habitats and between different forest types. Canonical correspondence analysis revealed a significant correlation between beetle community structure and the environment, showing distinct beetle assemblages to be significantly associated with specific edaphic and botanical features of the land-use gradient. This study adds to increasing evidence that landscape-scale patterns in land-use significantly affect beetle community structure producing distinct assemblages.     

Biotic and Abiotic Properties Mediating Plant Diversity Effects on Soil Microbial Communities in an Experimental Grassland

Plant diversity drives changes in the soil microbial community which may result in alterations in ecosystem functions. However, the governing factors between the composition of soil microbial communities and plant diversity are not well understood. We investigated the impact of plant diversity (plant species richness and functional group richness) and plant functional group identity on soil microbial biomass and soil microbial community structure in experimental grassland ecosystems. Total microbial biomass and community structure were determined by phospholipid fatty acid (PLFA) analysis. The diversity gradient covered 1, 2, 4, 8, 16 and 60 plant species and 1, 2, 3 and 4 plant functional groups (grasses, legumes, small herbs and tall herbs). In May 2007, soil samples were taken from experimental plots and from nearby fields and meadows. Beside soil texture, plant species richness was the main driver of soil microbial biomass. Structural equation modeling revealed that the positive plant diversity effect was mainly mediated by higher leaf area index resulting in higher soil moisture in the top soil layer. The fungal-to-bacterial biomass ratio was positively affected by plant functional group richness and negatively by the presence of legumes. Bacteria were more closely related to abiotic differences caused by plant diversity, while fungi were more affected by plant-derived organic matter inputs. We found diverse plant communities promoted faster transition of soil microbial communities typical for arable land towards grassland communities. Although some mechanisms underlying the plant diversity effect on soil microorganisms could be identified, future studies have to determine plant traits shaping soil microbial community structure. We suspect differences in root traits among different plant communities, such as root turnover rates and chemical composition of root exudates, to structure soil microbial communities.     

Bird assemblages in fragmented agricultural landscapes: the role of small brigalow remnants and adjoining land uses

Agricultural intensification typically leads to changes in bird diversity and community composition, with fewer species and foraging guilds present in more intensively managed parts of the landscape. In this study, we compare bird communities in small (2–32 ha) brigalow (Acacia harpophylla) remnants with those in adjacent uncultivated grassland, previously cultivated grassland and current cropland, to determine the contribution of different land uses to bird diversity in the agricultural landscape. Twenty remnant brigalow patches and adjacent agricultural (‘matrix’) areas in southern inland Queensland, Australia were sampled for bird composition and habitat characteristics. The richness, abundance and diversity of birds were all significantly higher in brigalow remnants than in the adjacent matrix of cropping and grassland. Within the matrix, species richness and diversity were higher in uncultivated grasslands than in current cultivation or previously cultivated grasslands. Forty-four percent of bird species were recorded only in brigalow remnants and 78% of species were recorded in brigalow and at least one other land management category. Despite high levels of landscape fragmentation and modification, small patches of remnant brigalow vegetation provide important habitat for a unique and diverse assemblage of native birds. The less intensively managed components of the agricultural matrix also support diverse bird assemblages and thus, may be important for local and regional biodiversity conservation.     

Local vs. landscape controls on diversity: a test using surface-dwelling soil macroinvertebrates of differing mobility

Aim A better understanding of the processes driving local species richness and of the scales at which they operate is crucial for conserving biodiversity in cultivated landscapes. Local species richness may be controlled by ecological processes acting at larger spatial scales. Very little is known about the effect of landscape variables on soil biota. The aim of our study was to partly fill this gap by relating the local variation of surface‐dwelling macroarthropod species richness to factors operating at the habitat scale (i.e. land use and habitat characteristics) and the landscape scale (i.e. composition of the surrounding matrix). Location An agricultural landscape with a low‐input farming system in Central Hesse, Germany. Methods We focused on five taxa significantly differing in mobility and ecological requirements: ants, ground beetles, rove beetles, woodlice, and millipedes. Animals were caught with pitfall traps in fields of different land use (arable land, grassland, fallow land) and different habitat conditions (insolation, soil humidity). Composition of the surrounding landscape was analysed within a radius of 250 m around the fields. Results Factors from both scales together explained a large amount of the local variation in species richness, but the explanatory strength of the factors differed significantly among taxa. Land use particularly affected ground beetles and woodlice, whereas ants and rove beetles were more strongly affected by habitat characteristics, namely by insolation and soil characteristics. Local species richness of diplopods depended almost entirely on the surrounding landscape. In general, the composition of the neighbouring landscape had a lower impact on the species richness of most soil macroarthropod taxa than did land use and habitat characteristics. Main conclusions We conclude that agri‐environment schemes for the conservation of biodiversity in cultivated landscapes have to secure management for both habitat quality and heterogeneous landscape mosaics.     

Landscape structure and land use history influence changes in island plant composition after 100 years

Aim We investigated how current and historical land use and landscape structure affect species richness and the processes of extinction, immigration and species turnover. Location The northern part of the Stockholm archipelago, Baltic Sea, Sweden. We resurveyed 27 islands ranging from 0.3 to 33 ha in area. Methods We compared current plant survey data, cadastral maps and aerial photographs with records obtained from a survey in 1908, using databases and a digital elevation model to examine changes in plant community dynamics in space and time. We examined the effects of local and landscape structure and land use changes on plant species dynamics by using stepwise regression in relation to eight local and three landscape variables. The eight local variables were area, relative age, shape, soil heterogeneity, bedrock ratio, number of houses, forest cover change, and grazing 100 years ago. The three landscape variables were distance to mainland, distance to closest island with a farm 100 years ago, and structural connectivity. Hanski’s connectivity measure was modified to incorporate both connectivity and fragmentation. Results The investigated islands have undergone drastic changes, with increasing forest cover, habitation, and abandonment of grassland management. Although the total species richness increased by 31% and mean island area by 23%, we found no significant increase in species richness per unit area. Local variables explain past species richness (100 years ago), whereas both local and landscape variables explain current species richness, extinctions, immigrations and species turnover. Grazing that occurred 100 years ago still influences species richness, even though grazing management was abandoned several decades ago. The evidence clearly shows an increase in nitrophilous plant species, particularly among immigrant species. Main conclusions This study highlights the importance of including land use history when interpreting current patterns of species richness. Furthermore, local environment and landscape patterns affect important ecological processes such as immigration, extinction and species turnover, and hence should be included when assessing the impact of habitat fragmentation and land use change. We suggest that our modified structural connectivity measure can be applied to other types of landscapes to investigate the effects of fragmentation and habitat loss.     

Density of insect‐pollinated grassland plants decreases with increasing surrounding land‐use intensity

Pollinator declines have raised concerns about the persistence of plant species that depend on insect pollination, in particular by bees, for their reproduction. The impact of pollinator declines remains unknown for species‐rich plant communities found in temperate seminatural grasslands. We investigated effects of land‐use intensity in the surrounding landscape on the distribution of plant traits related to insect pollination in 239 European seminatural grasslands. Increasing arable land use in the surrounding landscape consistently reduced the density of plants depending on bee and insect pollination. Similarly, the relative abundance of bee‐pollination‐dependent plants increased with higher proportions of non‐arable agricultural land (e.g. permanent grassland). This was paralleled by an overall increase in bee abundance and diversity. By isolating the impact of the surrounding landscape from effects of local habitat quality, we show for the first time that grassland plants dependent on insect pollination are particularly susceptible to increasing land‐use intensity in the landscape.     

Woody elements benefit bird diversity to a larger extent than semi-natural grasslands in cereal-dominated landscapes

Increasing landscape complexity can mitigate negative effects of agricultural intensification on biodiversity by offering resources complementary to those provided in arable fields. In particular, grazed semi-natural grasslands and woody elements support farmland birds, but little is known about their relative effects on bird diversity and community composition. In addition, the relative importance of local habitat versus landscape composition remains unclear. We investigated how the presence of semi-natural grasslands, the number of woody elements and the composition of the wider agricultural landscape affect bird species richness, true diversity (exponential Shannon diversity) and species composition. Bird communities were surveyed four times on 16 paired transects of 250 m each with 8 transects placed between a crop field and a semi-natural grassland and 8 transects between two crop fields with no semi-natural grasslands in the vicinity. The number of woody elements around transects was selected as an important predictor in all models, having a positive effect on species richness and true diversity, while the local presence of semi-natural grasslands was not selected in the best models. However, species richness and true diversity increased with increasing cover of ley and semi-natural grasslands, whereas species composition was modified by the coverage of winter wheat at the landscape scale. Furthermore, bird species richness, true diversity and species composition differed between sampling dates. As bird diversity benefited from woody elements, rather than from the local presence of semi-natural grasslands as such, it is important to maintain woody structures in farmland. However, the positive effect of grassland at the landscape scale highlights the importance of habitat variability at multiple scales. Because species richness and true diversity were affected by different landscape components compared to species composition, a mosaic of land-use types is needed to achieve multiple conservation goals across agricultural landscapes.     

Effects of land use and landscape patterns on Orthoptera communities in the Western Siberian forest steppe

Across Western Siberia, land use has changed substantially since the collapse of the Soviet Union in 1991: large cropland areas were abandoned and livestock numbers declined. In recent years these trends have partly been reversed, and an intensification of agricultural management has been observed that is still ongoing. We evaluated the impact of land use, as well as effects of landscape patterns and vegetation structure on Orthoptera communities and discuss them as drivers of community composition, species richness and abundance. We sampled Orthoptera using a box-quadrat on ancient grassland, ex-arable grassland (both including different management types: unmanaged, grazed and mown) and cereal fields. Landscape heterogeneity and composition strongly affected species richness and abundance of Orthoptera. Both were higher in grassland than in cropland, but did not differ significantly between ex-arable and ancient grasslands or different management practices. An Indicator Species Analysis revealed differentiation of Orthoptera communities between all management types. On croplands, the number of adult individuals and nymphs was influenced by the proportion of grassland in the surrounding landscape and tillage practices. Conservation tillage is most likely the key factor allowing Orthoptera to reproduce on croplands. After up to 24 years of succession, Orthoptera communities of ex-arable grasslands can be considered as completely recovered, as differences to ancient grasslands were minimal. Besides the continuation of low-intensity management, conservation strategies for this region should consider landscape composition and support habitat heterogeneity like ecotones with hemi-boreal forests in grassland-dominated landscapes.     

Effect of Agricultural Management Regime on Burkholderia Community Structure in Soil

The main objective of this study was to determine the Burkholderia community structure associated with areas under different agricultural management and to evaluate to which extent this community structure is affected by changes in agricultural management. Two fields with distinct soil history (arable land and permanent grassland) were exposed to three agricultural management regimes (crop rotation, maize monoculture, and grassland). By using a culture-independent approach, based on a Burkholderia-specific polymerase chain reaction–denaturing gradient gel electrophoresis system, it was possible to observe the conversion of Burkholderia communities typical for permanent grassland to those of arable land after four consecutive years. However, the time needed to achieve the reverse transition, i.e., converting the Burkholderia community associated with arable land to that of grassland, was beyond the duration of the field experiment. In addition, by applying principal response curves, the direction and extent of the conversion from grassland to arable land (maize monoculture and to crop rotation) were determined. Hence, the results suggested that agricultural practices, such as fertilization and tillage, were more effective in changing the Burkholderia community structure than agricultural management regime. To determine the effect of agricultural management on the Burkholderia population with biocontrol abilities, the culturable fraction of the Burkholderia community was assessed. The areas under permanent grassland and grassland converted to maize monoculture had the highest percentages of Burkholderia strains with antagonistic activity against Rhizoctonia solani AG-3, mainly Burkholderia pyrrocinia and Burkholderia sp. LMG 22929. The isolation frequency of antagonistic isolates from arable land was extremely low. Our results indicate that (changes in) agricultural management, mainly crop rotation, affect the frequency of isolation of antagonistic Burkholderia strains and that grassland represents a reservoir of Burkholderia species with great potential for agricultural applications.     

资源型城市土地利用变化的景观过程响应——以黑龙江省大庆市为例

土地利用与土地覆盖变化直接或间接地改变着景观生态系统的结构和功能,进而影响地表各种景观过程。地表景观过程的改变,必然对人类赖以生存的生态环境产生程度不同的影响。黑龙江省大庆市作为典型的资源型城市(以石油、草场和耕地资源发展起来),是人地关系作用最强烈的区域之一,也是土地利用发生急剧变化且具有特色的区域。揭示该区域土地利用的时空变化特征和变化规律,探讨土地利用变化的景观生态趋势及对生态环境的可能影响等,对于资源型城市生态环境改善,产业结构调整及实现资源型城市可持续发展尤为重要。为此,基于大庆市1978,1988,1992,1996,2001年5个时段的MSS和TM影像,获取20余年不同时期的土地利用信息,以GIS技术为数据集成分析平台,计算土地利用转移概率矩阵,景观格局指数和主要景观组分的转移过程贡献率,以期从景观格局的角度定量刻画区域景观过程对土地利用变化的响应。结果表明,区域内耕地不断增加,草地持续减少,建设用地和林地逐渐扩大,而湿地则一直大幅度减少;耕地和草地是区域的主要景观类型,但二者的景观动态及过程却不相同,耕地的景观过程表现为空间集中性加强,而草地的破碎化程度加强,景观组分间的转移过程频繁,景观不稳定;对维持当地生态系统稳定起重要作用的湿地景观,其破碎化过程最为明显且面积和平均斑块面积都在迅速减少,这种景观过程将对当地生态环境变化造成负面影响。草地退化,湿地萎缩和功能减退,沙化和盐碱化日趋严重等生态过程,是土地利用变化的景观生态过程响应,恢复与建设生态脆弱的资源型城市的景观生态系统,须对景观尺度上的土地利用方式进行合理的调控,而这一调控的有效途径在于政策、体制的调整和观念的变化。     

长春市不同土地利用生境土壤弹尾虫群落结构特征

对长春市郊区天然次生林、农田、防护林和市区公园绿地等典型土地利用生境进行土壤弹尾虫调查,研究土地利用差异对土壤弹尾虫群落结构的影响.结果表明,长春市土地利用差异对弹尾虫群落结构特征影响明显,地表凋落物移除和耕作活动是影响弹尾虫群落结构特征的主要因素,地表凋落物移除显著减少弹尾虫的个体数量和群落多样性,耕作活动影响弹尾虫个体数量在土体中的垂直分布;地表植物群落类型对土壤弹尾虫群落结构特征也有一定影响.     

Ring-based versus disc-based separation of spatial scales: a case study on the impact of arable land proportions on invertebrates in freshwater streams

The impact of different land-use types on species is traditionally estimated by correlating landscape proportions recorded in buffer areas around focal points with species data observed at these sites. If a high proportion of a specific land-use type exists within a small radius, it will be accumulated in larger buffers and may confound the interpretation at larger scales. We sampled freshwater invertebrates in ten streams using cages with artificial substrate and compared the effects of arable land proportions calculated in disc-shaped buffers of increasing radius versus areas calculated from non-overlapping rings of increasing radius. We hypothesize that (1) the accumulative disc-based approach leads to confounding effects across increasing buffer size and that (2) the use of ring-based methods facilitates the identification of relevant scales for conservation measures. The abundance of crustaceans showed a positive relationship with arable land proportions, but Plecoptera abundance and the taxonomic richness of Ephemeroptera and Plecoptera decreased with increasing arable land proportions in the surrounding landscape. Our results further support the presence of confounding effects in disc-based analyses, as correlations between arable land proportions and Crustacea, or Plecoptera, respectively, were affected by the accumulation of small-scale area proportions. The distance at which arable land proportions significantly affected benthic fauna in freshwater streams was consistently shorter if calculated from rings rather than from discs. Although an a priori definition of ring width introduces new challenges, a combined use of disc- and ring-based techniques for the estimation of land-use effects may substantially improve the realization of conservation and protection measures in terrestrial and aquatic systems.     

Edge effects on ant community structure and species richness in an agricultural landscape

The effect of sharp edges between three different types of land use on the species richness and structure of ant communities was examined in an agricultural landscape within Central Hesse, Germany. Species richness and nest densities of ants at the centres and the edges of meadows, crop fields, and fallow land were recorded by hand sampling during 1997 and 1998. Edges between different land-use types did not increase ant species richness at the landscape scale, nor were they unique habitats for a specialised ant fauna. Nonetheless, most species shared ecotonal effects in the way that their relative abundance either decreased (e.g. Myrmica scabrinodis) or increased (e.g. Lasius niger, Lasius flavus) at the edges, resulting in different community structure between edges and centres of the land-use types. This was influenced by two major factors: (i) the boundary contrast between the neighbouring habitats (i.e. in terms of disturbance caused by agricultural practices), and (ii) the response of different species to changing abiotic conditions. High nest densities of aggressive species with large colonies occurred along edges. We hypothesise that this can significantly reduce edge permeability for surface-dwelling arthropods.     

Assessing protected area network effectiveness through the temporal change in avian communities’ composition

Current rates of land use are driving temporal changes in avian communities. Thus, it is essential to properly designate and manage protected areas since they mitigate the adverse effects of temporal changes on species populations. By using common bird monitoring data in Czechia from two periods (2005/2006 and 2014/2015), we calculated two indices of temporal change per each site, the Jaccard dissimilarity index (temporal dissimilarity between the community composition) and the difference in bird species richness between both periods (delta bird species richness). We tested three main predictions on temporal change in bird communities between protected and unprotected areas: (i) bird species richness will be higher inside protected areas, (ii) temporal changes in avian communities will be lower inside protected areas, (iii) the effect of protected areas will interact with land-use types, land-use richness, and altitudinal zones. Bird species richness was higher inside protected areas in 2014/2015, ten years after the implementation of Natura 2000 in Czechia. Both indices of temporal change were lower inside protected areas. The interactions of protected areas and land-use types on the indices of temporal change were not significant. However, interactions with altitudinal zones had a significant positive effect on the indices, i.e., in higher altitudes, delta bird species richness and higher dissimilarity levels. Our study underlines the importance of protected areas for conservation by buffering the consequences of factors driving temporal community changes. Together, our results indicate a positive ‘umbrella’ effect of protected areas on avian communities that was likely facilitated by the implementation of Natura 2000.     

Arthropod Diversity and Community Structure in Relation to Land Use in the Mekong Delta, Vietnam

Declining biodiversity in agro-ecosystems, caused by intensification of production or expansion of monocultures, is associated with the emergence of agricultural pests. Understanding how land-use and management control crop-associated biodiversity is, therefore, one of the key steps towards the prediction and maintenance of natural pest-control. Here we report on relationships between land-use variables and arthropod community attributes (for example, species diversity, abundance and guild structure) across a diversification gradient in a rice-dominated landscape in the Mekong delta, Vietnam. We show that rice habitats contained the most diverse arthropod communities, compared with other uncultivated and cultivated land-use types. In addition, arthropod species density and Simpson’s diversity in flower, vegetable and fruit habitats was positively related to rice cover in the local landscape. However, across the landscape as a whole, reduction in heterogeneity and the amount of uncultivated cover was associated, generally, with a loss of diversity. Furthermore, arthropod species density in tillering and flowering stages of rice was positively related to crop and vegetation richness, respectively, in the local landscape. Differential effects on feeding guilds were also observed in rice-associated communities with the proportional abundance of predators increasing and the proportional abundance of detritivores decreasing with increased landscape rice cover. Thus, we identify a range of rather complex, sometimes contradictory patterns concerning the impact of rice cover and landscape heterogeneity on arthropod community attributes. Importantly, we conclude that that land-use change associated with expansion of monoculture rice need not automatically impact diversity and functioning of the arthropod community.