A Grid-Based Sampling Approach to Insect Biodiversity Monitoring in Agricultural Landscapes

Grassland management in agricultural vs. forested landscapes drives butterfly and bird diversity

Summary 1. Biotic homogenization (BH), a dominant process shaping the response of natural communities to human disturbance, reflects both the expansion of exotic species at large scales and other mechanisms that often operate at smaller scales. 2. Here, we examined the relationship between BH in plant communities and spatio-temporal landscape disturbance (habitat fragmentation and surrounding habitat conversion) at a local scale (1 km²), using data from a standardized monitoring programme in France. We quantified BH using both a spatial partitioning of taxonomic diversity and the average habitat specialization of communities, which informs on functional BH. 3. We observed a positive relationship between local taxonomic diversity and landscape fragmentation or instability. This increase in local taxonomic diversity was, however, paralleled by a decrease in average community specialization in more fragmented landscapes and in more unstable landscapes around forest sites. The decrease in average community specialization suggests that landscape disturbance causes functional BH, but there was limited evidence for concurrent taxonomic BH. 4. Synthesis. Our results show that landscape disturbance is partly responsible for functional BH at small scales via the extirpation of specialist species, with possible consequences for ecosystem functioning. However, this change in community composition is not systematically associated with taxonomic BH. This has direct relevance in designing biodiversity indicators: metrics incorporating species sensitivity to disturbance (such as species specialization to habitat) appear much more reliable than taxonomic diversity for documenting the response of communities to disturbance.

Grassland type and presence of management shape butterfly functional diversity in agricultural and forested landscapes

Scale dependence of pollinator community turnover and tritrophic interactions in changing landscapes

Landscape context of bee, wasp and parasitoid diversity: grass-strip corridors, fallows and food webs

Landscape structure, habitat fragmentation, and the ecology of insects

Fueled by debates on the causes and consequences of biodiversity decline worldwide, many countries are now employing biodiversity monitoring programs of various scope, intensity and scale. While these programs will be important to set a baseline for managing a country´s biological diversity, the availability of detailed data may take too long for the urgently needed implementation of biodiversity-friendly action. Intensification of local agricultural land use and the high dynamics of landscape change are major reasons for current biodiversity losses. Hence, better use of published and unpublished data to inform predictive biodiversity monitoring under global change is needed. Here, we exemplarily show how existing experiments manipulating land-use drivers can be used to predict species responses to land-use change. In an experimental manipulation of temperate grassland plots, fertilizer addition and low mowing frequency increased the species richness of aboveground arthropods, while herbicide addition and frequent mowing reduced it. In a crop rotation experiment, temporal crop diversity slightly increased arthropod abundances, but crop identity had the strongest effect on arthropod abundance, showing that the type of crop grown may superimpose crop diversity effects on arthropod communities. Finally, in a wheat-bean intercropping experiment, we found that the legume-based farming systems under low-input management had higher diversity of flower-visiting insect taxa. In an upscaling exercise, we show how current crop distribution data from the pan-European LUCAS survey can be combined with insect biodiversity data to suggest an approach for predictive mapping of insect biodiversity. These can form the basis for scenario modeling that is based on experimental evidence.KeywordsPredictive monitoringExperimental evidenceFarmlandCropsLanduseArthropods/invertebrates

Insects are the richest and most diverse group of animals and yet there remains a lack, not only of systematic research into their distribution across some key regions of the planet, but of standardized sampling strategies for their study. The Yanshan Mountains, being the boundary range between the Inner Mongolian Plateau and the North China Plain, present an indispensable piece of the insect biodiversity puzzle: both requiring systematic study and offering opportunities for the development of standardized methodologies. This is the first use of DNA metabarcoding to survey the insect biodiversity of the Yanshan Mountains. The study focuses on differences of community composition among samples collected via different methods and from different habitat types. In total, 74 bulk samples were collected from five habitat types (scrubland, woodland, wetland, farmland and grassland) using three collection methods (sweep netting, Malaise traps and light traps). After DNA extraction, PCR amplification, sequencing and diversity analysis were performed, a total of 7427 Operational Taxonomic Units (OTUs) at ≥97% sequence similarity level were delimited, of which 7083 OTUs were identified as belonging to Insecta. Orthoptera, Diptera, Coleoptera and Hemiptera were found to be the dominant orders according to community composition analysis. Nonmetric multidimensional scaling (NMDS) analysis based on Bray–Curtis distances revealed highly divergent estimates of insect community composition among samples differentiated by the collection method (R = .524802, p = .001), but nonsignificant difference among samples differentiated according to habitat (R = .051102, p = .078). The study therefore appears to indicate that the concurrent use of varied collection methods is essential to the accurate monitoring of insect biodiversity.

Neighbourhood-defined approaches for integrating and designing landscape monitoring in Estonia

Agriculture and wildlife conservation programs have converted vast amounts of cropland into grasslands planted with exotic species. Understanding how landscape context influences avian use of native and planted grasslands is essential for developing effective conservation strategies in agricultural landscapes. Our primary objective was to determine the extent to which the amount and type of grassland in the surrounding landscape influences the abundance of grassland songbird species on native and planted grassland parcels in southern Saskatchewan and Alberta, Canada. Bird abundance was more strongly influenced by the amount and type of grassland within 400 m of breeding parcels than at larger spatial scales. Grassland specialists responded similarly to habitat and landscape type over both years and provinces. Sprague's pipit (Anthus spragueii) and Baird's sparrow (Ammodramus bairdii) were most common in native grassland parcels surrounded by native grassland and were more likely to occur in planted grasslands surrounded by native grassland. Bobolinks (Dolichonyx oryzivorus) were most common in planted grassland parcels, but their abundance increased with the amount of native grassland surrounding these parcels. Our findings indicate that the suitability of planted grasslands for these species is influenced by their proximity to native grassland. Grassland generalists showed mixed responses to habitat and landscape type over the 2 years (Le Conte's sparrow [Ammodramus leconteii]) and between provinces (Savannah sparrow [Passerculus sandwichensis] and western meadowlark [Sturnella neglecta]). Management to benefit grassland specialists should therefore consider the landscape context when seeding cultivated land to non‐native grassland and conserve extant native grassland. © 2013 The Wildlife Society.

Genetically modified herbicide-tolerant (GMHT) oilseed rape (OSR; Brassica napus L.) was approved for commercial cultivation in Canada in 1995 and currently represents over 95% of the OSR grown in western Canada. After a decade of widespread cultivation, GMHT volunteers represent an increasing management problem in cultivated fields and are ubiquitous in adjacent ruderal habitats, where they contribute to the spread of transgenes. However, few studies have considered escaped GMHT OSR populations in North America, and even fewer have been conducted at large spatial scales (i.e. landscape scales). In particular, the contribution of landscape structure and large-scale anthropogenic dispersal processes to the persistence and spread of escaped GMHT OSR remains poorly understood. We conducted a multi-year survey of the landscape-scale distribution of escaped OSR plants adjacent to roads and cultivated fields. Our objective was to examine the long-term dynamics of escaped OSR at large spatial scales and to assess the relative importance of landscape and localised factors to the persistence and spread of these plants outside of cultivation. From 2005 to 2007, we surveyed escaped OSR plants along roadsides and field edges at 12 locations in three agricultural landscapes in southern Manitoba where GMHT OSR is widely grown. Data were analysed to examine temporal changes at large spatial scales and to determine factors affecting the distribution of escaped OSR plants in roadside and field edge habitats within agricultural landscapes. Additionally, we assessed the potential for seed dispersal between escaped populations by comparing the relative spatial distribution of roadside and field edge OSR. Densities of escaped OSR fluctuated over space and time in both roadside and field edge habitats, though the proportion of GMHT plants was high (93-100%). Escaped OSR was positively affected by agricultural landscape (indicative of cropping intensity) and by the presence of an adjacent field planted to OSR. Within roadside habitats, escaped OSR was also strongly associated with large-scale variables, including road surface (indicative of traffic intensity) and distance to the nearest grain elevator. Conversely, within field edges, OSR density was affected by localised crop management practices such as mowing, soil disturbance and herbicide application. Despite the proximity of roadsides and field edges, there was little evidence of spatial aggregation among escaped OSR populations in these two habitats, especially at very fine spatial scales (i.e. <100 m), suggesting that natural propagule exchange is infrequent. Escaped OSR populations were persistent at large spatial and temporal scales, and low density in a given landscape or year was not indicative of overall extinction. As a result of ongoing cultivation and transport of OSR crops, escaped GMHT traits will likely remain predominant in agricultural landscapes. While escaped OSR in field edge habitats generally results from local seeding and management activities occurring at the field-scale, distribution patterns within roadside habitats are determined in large part by seed transport occurring at the landscape scale and at even larger regional scales. Our findings suggest that these large-scale anthropogenic dispersal processes are sufficient to enable persistence despite limited natural seed dispersal. This widespread dispersal is likely to undermine field-scale management practices aimed at eliminating escaped and in-field GMHT OSR populations. Agricultural transport and landscape-scale cropping patterns are important determinants of the distribution of escaped GM crops. At the regional level, these factors ensure ongoing establishment and spread of escaped GMHT OSR despite limited local seed dispersal. Escaped populations thus play an important role in the spread of transgenes and have substantial implications for the coexistence of GM and non-GM production systems. Given the large-scale factors driving the spread of escaped transgenes, localised co-existence measures may be impracticable where they are not commensurate with regional dispersal mechanisms. To be effective, strategies aimed at reducing contamination from GM crops should be multi-scale in approach and be developed and implemented at both farm and landscape levels of organisation. Multiple stakeholders should thus be consulted, including both GM and non-GM farmers, as well as seed developers, processors, transporters and suppliers. Decisions to adopt GM crops require thoughtful and inclusive consideration of the risks and responsibilities inherent in this new technology.

This study conducts a comprehensive comparison of landscape feature data derived from different sources &amp;#8212; Small Woody Features (SWF) product from Copernicus Land Monitoring system, LUCAS Landscape Feature (LF) Module, and LUCAS Transect Module &amp;#8212; in EU agricultural landscapes. Additionally, we consider the European Monitoring of Biodiversity in Agricultural Landscapes (EMBAL) project's approach of in-situ data collection for land cover, landscape elements, and biodiversity. This approach offers a promising avenue for integrating detailed field survey data with broad-scale remote sensing observations. Furthermore the EMBAL project has the potential to enhance the previously mentioned datasets by incorporating additional information, such as the nature value of all surveyed land units, habitat types or pollination potential among others. This inclusion could contribute to having better insights&amp;#160; into the ecological significance and monitoring of agricultural landscapes. Our analysis further explores the potential of incorporating cutting-edge datasets for enhanced monitoring of landscape features. Specifically, we consider the high-resolution (3-meter) dataset from Liu et al. (2023), which presents a detailed canopy height map and quantifies tree cover and woody biomass across Europe.&amp;#160;We critically assess the strengths and limitations of each source: SWF's remote sensing foundation provides broad coverage but focuses only on woody features, the LUCAS LF Module combines photo-interpretation with field survey for a more detailed typology, and the LUCAS Transect, though discontinued, offered valuable field data for linear features. Strategies for monitoring landscape features have been considered for a long time, but are continually updated with the latest available data and methods. A comprehensive comparison and evaluation of the new data sources has not yet been carried out. Our study aims to identify complementarities between the different datasets to&amp;#160; improve both quantitative and qualitative monitoring of landscape features informing sustainable agricultural practices and biodiversity conservation strategies.

Calcareous grassland fragments as sources of bee pollinators for the surrounding agricultural landscape

During the last decade the conservation of biodiversity in agricultural landscapes has been greatly emphasized. Intensification of agricultural production and practices, as well as land abandonment, have been considered as major threats (Solbrig, 1991), by making drastic changes in landscape structure and composition. The agricultural landscape is a shifting mosaic of crops, pastures, fallow lands and woody areas. Landscape elements exhibit their own disturbance regime, which depends on the practices used by farmers and thus interact with insects at several spatio-temporal scales. Changes at regional and long-term scales are the most documented and the most predictive (Baker, 1989; Rackham, 1986; Odum and Turner, 1990; Meeus, 1995; Crumley and Marquardt, 1987). A recent trend in western Europe is a decrease of the area covered by non-cultivated elements such as hedgerows, woodlots, heathlands, within intensive agricultural landscapes (Agger and Brandt, 1988; Bunce and Hallam, 1993; Burel and Baudry, 1990; Morant et al., 1995). In the mean time large tracks of farmland are abandoned. Thus the contrast between different regions increases. The changes within rural landscapes result in an increase in fragmentation of many elements and affect insect populations by reducing available habitats or seasonal refuges for many species. At a finer scale, farmers make decisions on crop succession in their farming system and on management practices for field boundaries and non-productive areas; this creates a changing landscape mosaic. Changes in agricultural landscapes can only be predicted through the knowledge of how farmers will change the land use pattern under different circumstances. Two levels must be considered: 1) changes in the type of production (e.g. from dairy production to cereals) and 2) changes in the techniques of production (e.g. feeding dairy cows with hay or maize silage). If, at a broad regional scale, relationships between the type of farming systems and landscape can be established, it becomes very fuzzy at the landscape scale, relating to, the scales of individual and population dispersal. Deffontaines et al. (1995) provide examples of two farms, in the Pays d’Auge, where the most productive one has more grassland and less annual forage crops. In all cases, the within farm land use diversity is striking, it results from both physical and spatial constraints and the requirements of the system of production (e.g. winter/summer forage). Many factors, out of the agricultural sector, also affect land use and landscape patterns, as in multi-job farms (Laurent et al., 1994). Trajectories of households as well as changes within farm systems are barely related at the individual farm scale. The major consequence from a landscape ecological point of view is that landscape changes cannot be derived from current landscape patterns (Burel and Baudry, 1990). More specifically, abandonment or dereliction of grassland is a stochastic process at the landscape scale, although deterministic at the farm scale.

Maintaining connectivity for tropical rainforest mammals in agricultural landscapes