Diversity In Agricultural Landscapes Research Articles

The effects of crop diversity and crop type on biological diversity in agricultural landscapes: a systematic review protocol

Agricultural intensification is a well-known driver of biodiversity loss. Crop diversity and its changes over space and time drive land use intensity and impact biodiversity of agricultural landscapes, while meeting the growing demand for human food and nutrition resources. Loss of biodiversity in agricultural landscapes reduces primary productivity and soil health and erodes a range of other ecosystem services. At present, while having partial understanding of many processes, we lack a general synthesis of our knowledge of the links between crop diversity and biodiversity. We will therefore conduct a systematic review by searching multiple agriculture, ecology and environmental science databases (e.g. Web of Science, Geobase, Agris, AGRICOLA, GreenFILE) to identify studies reporting the impacts of crop diversity and crop type on the biological diversity of fauna and flora in agricultural landscapes. Response variables will include metrics of species richness, abundance, assemblage, community composition and species rarity. Screening, data coding and data extraction will be carried out by one researcher and a subset will be independently carried out by a second researcher for quality control. Study quality and risk of bias will be assessed. Evidence will first be mapped to species/taxa then assessed for further narrative or statistical synthesis based on comparability of results and likely robustness. Gaps in the evidence base will also be identified with a view toward future research and policy directions for nutrition, food systems and ecology.

The effects of crop diversity and crop species on biological diversity in agricultural landscapes: a systematic review protocol.

Agricultural intensification is a well-known driver of biodiversity loss. Diversity of crop production over space and time reduces land use intensity and may mitigate impacts on biodiversity while contributing to growing demand for human food and nutrition resources. Crop species are also known to have independent impacts on biodiversity. To date, reviews synthesising our knowledge of crop species and crop diversity-biodiversity links are missing. We will therefore conduct a systematic review by searching multiple agriculture, ecology and environmental science databases (e.g. Web of Science, Geobase, Agris, AGRICOLA, GreenFILE) to identify studies reporting the impacts of crop diversity and crop species on the biological diversity of fauna, flora and microbes in agricultural landscapes. Outcomes will include metrics of species richness, abundance, assemblage, community composition and species rarity. Screening, data coding and data extraction will be carried out by one reviewer and a proportion will be independently conducted by a second reviewer. Study quality and risk of bias will be assessed. Evidence will first be mapped by species/taxa then assessed for further narrative or statistical synthesis based on comparability of results and likely robustness. Gaps in the evidence base will also be identified with a view toward future research and policy directions for nutrition, food systems and ecology.

Local and landscape habitat influences on bee diversity in agricultural landscapes in Anolaima, Colombia

Agricultural intensification drives biodiversity loss and is associated with bee declines. Bees are highly sensitive to environmental change, and while their diversity declines in simplified habitats distant from undisturbed areas, bees respond to agricultural practices and habitat configuration at different scales. Mountainous tropical agroecosystems are highly heterogeneous at local and landscape scales, and the responses of bee communities to environmental change in these regions are still underexplored. We examined the local and landscape habitat factors influencing bee abundance and diversity, and changes in bee generic and tribe composition in Anolaima, Colombia. We surveyed bees, measured local habitat features such as flower abundance, tree diversity, ground cover and vegetation structure, and evaluated land cover types and landscape characteristics in seventeen farms. We found that elevation, vertical structure of the vegetation and landscape structure influenced bee community structure. While local factors predicted the response of most individual bee groups, landscape factors influenced the abundance of Apis and Trigona, two genera with disproportionately high abundances across study sites. We also found that human constructions serve as refuges for several bee genera. Our paper suggests a process of biotic homogenization with the loss of bee diversity and concurrent spread of Apis and Trigona in landscapes dominated by pastures, unshaded crops or eroded soils. We also highlight the high sensitivity of native bees to habitat configuration and disturbance, and the importance of traditional farming systems for the conservation of bee communities in mountainous tropical agroecosystems.

黄淮平原农业景观鸟类多样性及生境差异

PDF HTML阅读 XML下载 导出引用 引用提醒 黄淮平原农业景观鸟类多样性及生境差异 DOI: 10.5846/stxb201712132246 作者: 作者单位: 河南大学黄河中下游数字地理技术教育部重点实验室;河南大学环境与规划学院,河南大学生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31600374，41371195）；河南省教育厅科学技术研究重点项目（16A180022）；河南省博士后科研项目（2015049） Bird diversity during the breeding period in different habitats in an agricultural landscape in the Huang-Huai plain Author: Affiliation: Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, Henan University, Kaifeng, China; College of Environment and Planning, Henan University, Kaifeng, China,School of Life Sciences, Henan University, Kaifeng, China Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 31600374, 41371195 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:农业景观中的鸟类多样性对生态系统功能和服务的形成与维持具有重要作用。黄淮平原区是我国最重要的农业景观区之一，为探讨区域内农业景观中鸟类多样性特征和不同生境间的差异，在研究区农业景观不同生境中布设样点，调查繁殖期鸟类多样性特征。结果显示：（1）共记录到32科、49属、66种的10044只个体，但优势科属明显；（2）物种丰富度、多样性和均匀度均表现出在沟渠、湖泊生境中较高，农田和村庄生境中相对较低，但物种多度呈现出村庄生境中最高，其次是沟渠和农田生境，湖泊生境中最低；（3）在区系分布上，各生境中均以广布种为主，生态类群上，鸣禽在各生境中均占绝对优势，涉禽和游禽主要分布在沟渠和湖泊生境中，从居留型来看，留鸟是各生境中的主导类群，候鸟、旅鸟和迷鸟比例很低；（4）鸟类群落异质性分析显示，各生境间的相似性总体上较高，表明区域内农业景观中鸟类组成具有较高的重叠性。研究显示农业景观中湖泊和沟渠的存在能有效的提高区域鸟类的丰富度和多样性，而沟渠的存在能有效的提高鸟类个体多度，农田和村庄有助于特定类群多度的增加，因此在未来的区域持续农业景观的构建中一方面要重视自然、半自然非农生境的作用，另一方面也不能忽视不同生物类群对景观异质性响应和对生境特征需求的差异。 Abstract:The diversity of birds in agricultural landscapes plays an important role in the formation and maintenance of ecosystem functions and services. The Huang-Huai plain is among the most important agricultural areas in China. With the continuing expansion of agricultural lands and the intensification of land-use, bird diversity in agricultural landscapes is declining all worldwide. To explore the diversity of birds in different habitats of the agricultural landscape in the Huang-Huai plain, we set up transects across different habitats in this area and investigated bird diversity characteristics during the breeding period. Our results showed that:(1) a total of 10044 individuals in 32 families, 49 genera, and 66 species were recorded; however, several families and genera were obviously dominant. (2) Species richness, diversity, and evenness were all higher in the habitats of ditch and lake, and relatively low in habitats of farmland and village. However, species abundance was highest in the village habitat, followed by ditch and farmland habitats, whereas in the lake habitat it was the lowest. (3) Analysis of faunal distribution showed that cosmopolitan species dominated any given habitat. In terms of ecological groups, the songbirds were the dominant species in all habitats, whereas the waders and swimming-birds were mainly distributed in the ditch and lake habitats. In terms of residence type, however, residents formed the dominant group in all habitats, and migrators, travelers, and stragglers appeared occasionally. (4) The high community similarity among the habitats indicated that bird species compositions were overlapped substantially across habitats in the agricultural landscape. Overall, the habitats of ditch and lake in the agricultural landscape could effectively improve the regional species richness and diversity, and the presence of ditches could further increase the abundance of birds, whereas the habitats of farmland and village may only enhance the abundance of specific bird species. This study emphasized the potential contributions of natural and semi-natural habitats to the construction of a sustainable agricultural landscape in the future; however, the differences in the responses to landscape heterogeneity and habitat requirements of different biological groups should not be ignored. 参考文献 相似文献 引证文献

Crop diversity and stability of revenue on farms in Central Europe: An analysis of big data from a comprehensive agricultural census in Bavaria

Diversity of agricultural landscapes is important to maintain the provision of ecosystem services. In face of decreasing support measures for agricultural markets in the European Union, diversified crop portfolios could also offer a possibility to stabilize revenue at farm level (portfolio effect). We hypothesize that (i) diversity of crop portfolios changes along spatial gradients in the study area (Bavaria, Germany), (ii) the composition of portfolios depends on farm parameters, and (iii) more diverse portfolios on arable land provide higher revenue stability. We analysed agricultural census data comprising all farms (N = 105 314) in the study area and identified 26 typical crop portfolios. We show that portfolio composition is related to farm characteristics (whole farm revenue, farm type, farm size) and location. Currently, diversification of crop portfolios fails to promote stability of portfolio revenue in the study area, where policy still indirectly influences market prices of energy crops. We conclude that the portfolio effect as a natural insurance was less important in recent years due to high market prices for specific crops. This low need for natural insurances probably favoured simplified portfolios leading to decreased agricultural diversity.

Maize‐dominated landscapes reduce bumblebee colony growth through pollen diversity loss

Abstract Bumblebees are important pollinators for a wide range of crops and wild plants. Performance of their colonies depends on pollen and nectar as food resources, but flowering plants are scarce in modern agricultural landscapes. It is well‐known that semi‐natural habitats can enhance floral resources and bumblebee abundance, but the impact of different crop types and their heterogeneity at the landscape scale remains unclear. We tested the effect of two different crop types (oilseed rape [OSR] and maize) and of configurational (field border density) and compositional heterogeneity (crop diversity) on weight gain of buff‐tailed bumblebee colonies (Bombus terrestris) and the pollen diversity collected by them in 20 landscapes in Central Germany. We found that augmenting maize cover had a detrimental effect on pollen diversity collected by bumblebees, probably due to intensive management resulting in low plant diversity. This low pollen diversity translated into reduced colony growth, since colonies with high pollen diversity gained more weight than colonies with low pollen diversity. In contrast, OSR cover and configurational and compositional heterogeneity did neither affect colony growth nor pollen diversity. However, for OSR, the timing of the flowering period was important. When OSR fields had a high flower cover at the end of the OSR blooming period, colonies showed increased growth rates. Synthesis and applications. Our results complement previous laboratory studies by showing that high pollen diversity leads to better colony performance under field conditions. Therefore, the maintenance of floral diversity in agricultural landscapes is crucial to ensure that bumblebees can fulfil their nutritional needs. However, the heterogeneity of crops, at least under the currently very low levels of crop rotation, does not contribute to this aim. In contrast, crop identity and timing of mass‐flowering crops turned out to be important factors, as maize reduced pollen resources, while late blooming oilseed rape (OSR) was beneficial to bumblebee colonies. Hence, maize cover per landscape should be reduced and strategies to enhance landscape wide flower diversity, especially towards and after the end of oilseed rape bloom, should be promoted to support bumblebee colonies that provide important pollination services.

Plant genus (Acacia and Eucalyptus) alters soil microbial community structure and relative abundance within revegetated shelterbelts

The composition of native woody vegetation communities in restored agricultural landscapes can alter plant-soil interactions and thus ecological function. This study investigated the effects of primary species groups (Acacia, Eucalyptus) used in shelterbelts in south-eastern Australia on soil microbial community structure, compared with those under adjacent pastures. The quantity and structure of bacterial and fungal communities was analysed using quantitative PCR (qPCR) and terminal restriction fragment length polymorphism (TRFLP). The fungal:bacterial ratio was highest under Eucalyptus trees but did not differ between Acacia and pasture. Both fungal and bacterial communities varied at different depths in the soil profile and across sampling periods. The dominant tree genus was a significant factor in observed differences in bulk soil bacterial and fungal communities compared to the surrounding pasture. The effect of tree type on fungal communities was more pronounced than on bacterial communities. Fungal communities not only differed between shelterbelts and pastures, but also between Acacia and Eucalyptus dominated shelterbelts; these patterns were consistently observed at different soil depths. Shelterbelt systems which contain a mixture of different plant genera have the potential to exhibit greater microbial community heterogeneity than single species plantations. Maintaining a variety of tree species during afforestation may therefore contribute to conserving important bacterial and fungal diversity in agricultural landscapes.

Landscape heterogeneity rather than crop diversity mediates bird diversity in agricultural landscapes.

Crop diversification has been proposed as farm management tool that could mitigate the externalities of conventional farming while reducing productivity-biodiversity trade-offs. Yet evidence for the acclaimed biodiversity benefits of landscape-level crop diversity is ambiguous. Effects may strongly depend on spatial scale and the level of landscape heterogeneity (e.g. overall habitat diversity). At the same time, contrasting within-taxon responses obscure benefits to specific functional groups (i.e. species with shared characteristics or requirements) if studied at the community level. The objectives of this study were to 1) disentangle the relative effects of crop diversity and landscape heterogeneity on avian species richness across five spatial scales ranging from 250 to 3000 m radii around focal winter wheat fields; and 2) assess whether functional groups (feeding guild, conservation status, habitat preference, nesting behaviour) determine the strength and direction of responses to crop diversity and landscape heterogeneity. In central Germany, 14 landscapes were selected along independent gradients of crop diversity (annual arable crops) and landscape heterogeneity. Bird species richness in each landscape was estimated using four point counts throughout the breeding season. We found no effects of landscape-level crop diversity on bird richness and functional groups. Instead, landscape heterogeneity was strongly associated with increased total bird richness across all spatial scales. In particular, insect-feeding and non-farmland birds were favoured in heterogeneous landscapes, as were species not classified as endangered or vulnerable on the regional Red List. Crop-nesting farmland birds, however, were less species-rich in these landscapes. Accordingly, crop diversification may be less suitable for conserving avian diversity and associated ecosystem services (e.g. biological pest control), although confounding interactions with management intensity need yet to be confirmed. In contrast, enhancement of landscape heterogeneity by increasing perennial habitat diversity, reducing field sizes and the amount of cropland has the potential to benefit overall bird richness. Specialist farmland birds, however, may require more targeted management approaches.

Effect of agricultural landscape diversity on mammalian wild animal species diversity: Case of Atabey plain

Effect of agricultural landscape diversity on mammalian wild animal species diversity: Case of Atabey plain

Honey bee foraging ecology: Season but not landscape diversity shapes the amount and diversity of collected pollen.

The availability of pollen in agricultural landscapes is essential for the successful growth and reproduction of honey bee colonies (Apis mellifera L.). The quantity and diversity of collected pollen can influence the growth and health of honey bee colonies, but little is known about the influence of landscape structure on pollen diet. In a field experiment, we rotated 16 honey bee colonies across 16 agricultural landscapes, used traps to collect samples of collected pollen and observed intra-colonial dance communication to gain information about foraging distances. DNA metabarcoding was applied to analyze mixed pollen samples. Neither the amount of collected pollen nor pollen diversity was related to landscape diversity. However, we found a strong seasonal variation in the amount and diversity of collected pollen in all sites independent of landscape diversity. The observed increase in foraging distances with decreasing landscape diversity suggests that honey bees compensated for lower landscape diversity by increasing their pollen foraging range in order to maintain pollen amount and diversity. Our results underscore the importance of a diverse pollen diet for honey bee colonies. Agri-environmental schemes aiming to support pollinators should focus on possible spatial and temporal gaps in pollen availability and diversity in agricultural landscapes.

Paddy management for potential conservation of endangered Itasenpara bitterling via zooplankton abundance

Abstract In recent decades, the decline of biodiversity due to land-use changes in agricultural landscapes has become a central issue in ecology. Paddy management practices support animal diversity in agricultural landscapes. Using an endangered fish (the Itasenpara bitterling) inhabiting rivers connected to paddy fields as its subject, this study investigated two hypotheses: first, paddy field management affects the spatial distribution of Itasenpara bitterling in the adjacent river, and second, zooplankton and warm water supplied by paddy fields to the adjacent river are the primary factors influencing bitterling abundance. To model habitat suitability for the juvenile Itasenpara bitterling, rivers around paddy fields were examined using geographical information system tools and field survey methods in conjunction with a generalized linear model. The supply of zooplankton from paddy fields to the adjoining river positively contributed to juvenile Itasenpara bitterling abundance. This finding suggests that paddy management practices contribute to zooplankton abundance, and thus increase habitat suitability for juvenile Itasenpara bitterling.

Pollinator diversity in different habitats of the agricultural landscape in the middle and lower reaches of the Yellow River based on the three-color pan trap method

The middle and lower reaches of the Yellow River constitute one of the most important grain-producing areas in China and strategic position for national food security. The maintenance of pollinator diversity in agricultural landscapes is not only meaningful for biodiversity protection, but also a guarantee of food security and crop production. Pollinators have response preferences to the color of nectar and pollen plants in different habitats. The diversity of pollinator in different habitats was analyzed by using multivariable ANOVA. Results showed that a total of 23,264 individuals were captured, which belong to 7 orders and 84 families. The difference individuals of pollinators in two habitats was highly significant (P<0.001). Approximately twice as many individuals were captured in farmland habitat than that in woodland habitat. The values of the Margalef richness index and the Berger-Parker dominance index were also greater in farmland habitat than that in woodland habitat. In both habitats, differences in pollinator diversity were significantly higher for the yellow traps than that for the other two colors (P<0.01); differences in the individual abundance in the yellow traps are highly significantly greater (P<0.001) than that for the other two colors, while there was no significant difference between the white and blue traps. The sensitivity of orders Diptera and Hymenoptera was greatest to yellow traps, followed by that to white and blue traps, while order Coleoptera showed no obvious preference among the three colors. With respect to species richness, white traps could capture the most pollinators in different habitat types; with respect to the individual abundance, yellow traps attracted the most pollinators. The results also show that some species had a specific preference for color. For example, Drosophilidae in both farmland and woodland habitats preferred white, and Eulophidae preferred yellow only in farmland. This is because pollinators respond differently to different intensities, wavelengths, and reflectivity, which is as a result of both innate preferences and learning. Pollinators respond differently to the three colored traps, and these traps could be used in a complementary manner for pollinator capture. Color pan traps can be seen as an effective method to obtain pollinators, which can use in various studies on pollinators in this research area.

Enhancing plant diversity in agricultural landscapes promotes both rare bees and dominant crop‐pollinating bees through complementary increase in key floral resources

Summary Enhancing key floral resources is essential to effectively mitigate the loss of pollinator diversity and associated provisioning of pollination functions in agro‐ecosystems. However, effective floral provisioning measures may diverge among different pollinator conservation targets, such as the conservation of rare species or the promotion of economically important crop pollinators. We examined to what extent such diverging conservation goals could be reconciled. We analysed plant–bee visitation networks of 64 herbaceous semi‐natural habitats representing a gradient of plant species richness to identify key resource plants of the three distinct conservation target groups: rare bees (of conservation concern), dominant wild crop‐pollinating bees and managed crop‐pollinating bees (i.e. honeybees). Considering overall flower visitation, rare bees tended to visit nested subsets of plant species that were also visited by crop pollinators (46% and 77% nestedness in the dissimilarity between rare bees and wild crop pollinators or managed honeybees respectively). However, the set of preferred plant species, henceforth ‘key plant species’ (i.e. those species disproportionately more visited than expected according to their floral abundance) was considerably more distinct and less nested among bee target groups. Flower visits of all bee target groups increased with plant species richness at a similar rate. Importantly, our analyses revealed that an exponential increase in the flower abundance of the identified key plant species and complementarity in the bee visitation pattern across plant species ─ rather than total flower abundance ─ were the major drivers of these relationships. Synthesis and applications. We conclude that the multiple goals of preserving high bee diversity, conserving rare species and sustaining crop pollinators can be reconciled if key plant species of different target groups are simultaneously available. This availability is facilitated by a high floral resource complementarity in the plant community. The list of identified key resource plant species we provide here can help practitioners such as land managers and conservationists to better design and evaluate pollinator conservation and restoration measures according to their goals. Our findings highlight the importance of identifying and promoting such plant species for pollinator conservation in agricultural landscapes.

Relative effects of landscape composition and configuration on multi-habitat gamma diversity in agricultural landscapes

Landscape composition and configuration are considered important factors influencing biodiversity in agricultural landscapes. Evaluating the relative importance of each component is complicated because they are often correlated. Overcoming this problem could lead to a better understanding of the mechanisms that drive biodiversity and help to determine effective actions. Usually, landscape-biodiversity relationships are studied at the local scale for a single habitat type (alpha diversity). However, for a better understanding of ecological processes at the landscape scale, it is also important to look at the overall diversity at the landscape level, including all habitat types. The present study was conducted to determine the relative effects of landscape composition and configuration on multi-habitat gamma diversity of carabid beetles and vascular plants in an agricultural region of western France. Twenty 1km2 landscapes were sampled for plants and carabids. Data from 10 sampling sites representing crop fields, grasslands and woody covers in each landscape were pooled to obtain the total multi-habitat gamma diversity. Results showed that both landscape composition and configuration influenced carabid communities, while only landscape composition affected plant communities. Carabid species richness increased with increasing length of edge between crops and grasslands. Plant richness was negatively and positively affected by the percentage of crops and grasslands respectively. Carabid species composition was more dissimilar between landscapes with increasing difference in percentage of woody covers and crops, and length of grassy-crop edge. Plant species composition was more dissimilar between landscapes with a greater difference in percentage of crops. These results suggest grassy-crop adjacencies may enhance processes of resource complementation between habitats for carabids, while habitat availability and quality are the main factors for plants. This approach provided new insights for sustaining overall biodiversity in agricultural landscapes: e.g. encourage adjacencies between grasslands and crop fields and continue to subsidise grasslands for plant diversity.

Avian Species and Functional Diversity in Agricultural Landscapes: Does Landscape Heterogeneity Matter?

While the positive relationship between avian diversity and habitat heterogeneity is widely accepted, it is primarily based on observed species richness without accounting for imperfect detection. Other facets of diversity such as functional diversity are also rarely explored. We investigated the avian diversity-landscape heterogeneity relationship in agricultural landscapes by considering two aspects of diversity: taxonomic diversity (species richness) estimated from a multi-species dynamic occupancy model, and functional diversity (functional evenness [FEve] and divergence [FDiv]) based on traits of occurring species. We also assessed how agricultural lands enrolled in a conservation program managed on behalf of declining early successional bird species (hereafter CP38 fields, an agri-environment scheme) influenced avian diversity. We analyzed breeding bird data collected at CP38 fields in Mississippi, USA, during 2010–2012, and two principal components of environmental variables: a gradient of heterogeneity (Shannon’s landscape diversity index) and of the amount of CP38 fields (percent cover of CP38 fields; CP38). FEve did not show significant responses to environmental variables, whereas FDiv responded positively to heterogeneity and negatively to CP38. However, most FDiv values did not significantly differ from random expectations along an environmental gradient. When there was a significant difference, FDiv was lower than that expected. Unlike functional diversity, species richness showed a clear pattern. Species richness increased with increasing landscape heterogeneity but decreased with increasing amounts of CP38 fields. Only one species responded negatively to heterogeneity and positively to CP38. Our results suggest that the relationships between avian diversity and landscape heterogeneity may vary depending on the aspect of diversity considered: strong positive effects of heterogeneity on taxonomic diversity, but weakly positive or non-significant effects on functional diversity. Our results also indicate that effectiveness of CP38 in conserving avian diversity, particularly, taxonomic diversity, could be limited without the consideration of landscape heterogeneity.

Relationships among ecological traits of wild bee communities along gradients of habitat amount and fragmentation

Amount of semi‐natural habitats (permanent grasslands, woodlands and hedgerows) and their level of fragmentation are among the main determinants of wild bee diversity in agricultural landscapes. However, their impact on the distribution of bee ecological traits has received little attention. In this study, we aimed to explore whether changes in the distribution of bee ecological traits along gradients of habitat amount and fragmentation were due to a direct effect of landscape context on multiple traits (‘response traits’) or to a correlation of response traits with other ecological traits not involved in the response of bee species to landscape context. In two study regions in southwest France and southeast Australia, we used a RLQ analysis (three‐table ordination method) to link bee traits with habitat amount and fragment isolation measured at the landscape scale. We found that bee ecological traits shifted at the community‐level in association with landscape gradients, whereas species‐level associations among bee traits and phylogenetic clustering in bee communities were of only minor importance in determining such shifts. We found that traits such as body size and nest location were closely linked to habitat amount and fragmentation. We also observed regionally‐specific relationships among ecological traits, suggesting that the regional species pool can play an important role in determining the response of bee communities to habitat amount and fragmentation. Our findings suggest that improved knowledge about how trait‐based responses mediate the impact of landscapes on wild bee communities will allow better prediction and understanding of subsequent effects on ecosystem functioning.

Plant diversity and determinant factors across smallholder agricultural management units in Central Ethiopia

Forests in the highlands of Ethiopia have declined considerably, and the supply of forest-based ecosystem services is eroding. Managing agricultural landscapes as well as enhancing plant biodiversity in agro-ecosystems is and will continue to be one possible strategy to preserve biodiversity, ensure an ecosystem service supply and sustain agricultural productivity. This study investigated the current status and prospects of plant diversity and its determinants in an agricultural landscape dominated by smallholder farmers in Southern Ethiopia. Specifically, the study investigated effects of land use, altitudinal gradient, wealth status and household attributes on plant diversity in agricultural landscapes. A complete count, Y-frame transect sampling method and household interviews were used for the study involving 39 households and 115 sample plots. A total of 166 plant species belonging to 134 genera and 56 families were recorded in all land use types. Of these, 101 were woody plant species (51 trees and 50 shrubs), while 65 were cultivated herbs and grasses. Land use, altitude and household wealth status significantly influenced tree and shrub species richness. Among land uses, home gardens hosted the highest number of tree and shrub species. Upper altitudes and rich households also had the highest tree and shrub species richness compared to others. Plant diversity indices (Shannon, Simpson and Margalef) were affected by altitude, wealth status and land use types. Household location, wealth status, the household attributes of landholding and family size had strong and positive influences on the tree species diversity and woody stem density of households, while educational background and off-farm income were negatively related with household-owned tree stem density. Species preference ranking, seedling demand and importance value index computations indicated the dominance of exotic tree species, which may suggest their economic importance over indigenous tree species. In the long term, this might lead to dominance of exotic tree species in the landscapes, which could cause a potential future threat to the remnant indigenous plant diversity that is currently finding refuge in the agricultural landscapes.

Temporal evolution of varietal, spatial and genetic diversity of bread wheat between 1980 and 2006 strongly depends upon agricultural regions in France

An in-depth analysis of the spatio-temporal evolution of crop diversity in agricultural landscapes is necessary to provide insights on how to improve the resilience of agroecosystems to climate instability and new pest pressures by increasing in situ crop diversity, while promoting a greater sustainability of agriculture. However, most of the indicators of crop diversity used in previous studies were based on ex situ genetic diversity, or on official lists of varieties or breeding programs, without taking acreage of the varieties actually grown in farmers’ fields into account. Acreage of varieties represent however a relevant information to assess the actual genetic vulnerability of a crop (genetic uniformity at landscape scale) cultivated in the considered regions over the period studied. To bridge this gap, we analyzed spatial varietal and genetic diversity of bread wheat in France – an important production area – over the 1980–2006 period at a yearly time step and a district scale, i.e. ‘département’. We used HT*, an indicator integrating both the spatial evenness of variety distribution and molecular genetic data, to finely examine the spatio-temporal evolution of spatially weighted bread wheat genetic diversity. We also computed several simpler and complementary indicators accounting for the number of varieties, the spatial varietal diversity and the genetic diversity, and we estimated the individual contribution of these simpler indicators to the spatio-temporal structure of the spatial genetic diversity HT*. HT* values showed significant but non linear temporal evolutions between 1980 and 2006, these evolutions being besides spatially structured. Moreover, both spatial varietal diversity and genetic diversity partly explained these temporal changes of HT* values while the number of varieties appeared non-explanatory. Similarly to HT*, all indicators studied also showed substantial differences of temporal changes among major French agricultural regions, furthermore sometimes opposite for varietal and genetic diversity. As an example, in the north of France, varietal richness and spatial varietal diversity showed a substantial increase, suggesting the adoption of an increasing number of bread wheat varieties by farmers in this region. However, considering that genetic diversity showed a slight but continuous decrease over the recent period, this could suggest an increase in genetic similarity among bread wheat varieties chosen by farmers. Taken as a whole, our results suggest that several determinants of crop diversity, such as the shortening of crop sequences or the recurrence of epidemics of some pathogens, could differentially affect varietal choices of farmers and thus the spatial structuration of the temporal changes of crop diversity. Finally, our results question the dominant use of ex situ nationwide datasets to characterize the evolution of spatial genetic diversity as a proxy of genetic vulnerability of a crop to face with future changes.

Villages and their old farmsteads are hot spots of bird diversity in agricultural landscapes

Summary To counteract the decline of farmland biodiversity in Europe, it is crucial to recognize habitats that are hot spots. Old rural settlements (e.g. villages) may be such important habitats, although these presumably biodiversity‐rich habitats have received little attention. Socio‐economic changes in central‐eastern Europe since 1989 mean that old homesteads and farmsteads are being replaced by new ones. We investigated bird species composition, richness and abundance at three spatial scales (single rural property, village and landscape) in the farmland of Poland to test: (i) their association with age (built before vs. after 1989) and type of property (farmstead vs. homestead), (ii) their relationship with the increasing share of new homesteads at the village scale and (iii) the difference in diversity between the village environment and four other environments (open fields, forest–field ecotones, forests and towns) at the landscape scale. At the single property scale, 15 out of 33 species preferred old farmsteads, while only one species preferred new homesteads. Old properties hosted a higher number of species and individuals than new ones, and farmsteads hosted a higher number of species than homesteads. At the village scale, bird species richness and abundance were markedly negatively associated with the proportion of new homesteads. At the landscape scale, species composition differed between villages and the other environments, and villages had the highest average bird abundance. Synthesis and applications. Rural villages and old farmsteads are important habitats for many farmland birds; thus, the increasing number of new homesteads not associated with farmland production will likely lead to a substantial further decline of farmland bird numbers and biodiversity. To counteract this process, we recommend (i) implementing educational programmes to develop rural residents’ awareness about the importance of farmsteads and homesteads for biodiversity, (ii) including villages and farmsteads and consideration of bird‐friendly habitats within these as part of EU conservation policies and (iii) compensating for changes in the structure of rural villages by increasing the amount of similar alternative habitats in the surrounding landscape.

River Dikes in Agricultural Landscapes: The Importance of Secondary Habitats in Maintaining Landscape-Scale Diversity

Lowland rivers and their floodplains have changed markedly over the last centuries. River dikes have become among the most extensive secondary habitats of former floodplains. Our main question was, what role do secondary habitats on river dikes play in harbouring plant species and maintaining plant diversity of lowland landscapes dominated by agricultural areas? We compared historical maps and current habitat maps to understand the effects of landscape changes on the vegetation pattern of the study region, in southern Hungary. Dikes and primary vegetation of the landscape were selected for intensive vegetation sampling. We compared the floristic similarity and the Shannon diversity of the vegetation types. We used ordinations to visualize relationships among the vegetation types and among dike vegetation and environmental variables. Our results indicated that profound changes have been brought about in the vegetation during the last 150 years, resulting in a transition from marshland to agricultural land. The species composition and pattern of dike vegetation strongly depended on their relative position to the river and their aspect. We conclude that dikes can harbour many vascular plants that are absent or rare in the surrounding habitats and therefore play a decisive role in maintaining plant diversity in agricultural landscapes.