Levels Of Management Intensity Research Articles

Optimal regimes of prescribed burning in forest plantations in the presence of risk of wildfires in the southeastern United States

We examine the optimal timing of prescribed burning and its effect on the optimal forest management of a forest plantation under wildfire risk in the southeastern United States. Based on the frequency of prescribed fires and wildfire risk, we define different management regimes, assuming that the forest stand can be completely destroyed and partially destroyed–considering a salvage rate of k = 15% and 30%– after a wildfire. Our results indicate that more intensive forest management requires more prescribed fires, resulting in higher costs of prescribed burning. In scenarios with low, medium, and high levels of management intensity, the fully destroyed stand requires 6, 12, and 16 prescribed fires, with costs of $150.4, $168.8, and $264.5 acre−1, respectively. The partially destroyed stand requires 6, 12, and 21 prescribed fires with costs of $89.1(k = 0.15) and $86.9(k = 0.3), $180.5(k = 0.15) and $227.1 (k = 0.3), and $326.8(k = 0.15) and $326.1(k = 0.3) acre−1. The economic rents associated with prescribed burning are relatively small, with most of the changes being driven by the reduction of wildfire risk. Without risk of wildfires, prescribed fires might not be necessary. In such cases, the use of herbicides or a combination of prescribed burning and herbicides could be more appropriate.

Modelling phosphorus dynamics in four European long-term experiments

CONTEXTPhosphorus (P) is a non-renewable geological macronutrient that plays an essential role in food security. The excessive use of P as a fertilizer and its subsequent diffuse loss leads to the deterioration of water quality, eutrophication, and loss of biodiversity. Ecosystem process-based models are a powerful tool to depict the P cycle, investigate the effects of management practices and climate change, and ultimately assess policy interventions that affect biogeochemical cycles. Of the limited number of P models in agricultural production systems, none have been tested in temperate conditions for periods of decades using long-term field experiments. OBJECTIVEThe objective of this study is to evaluate the ability of the detailed P submodel from DayCent to: simulate the magnitude and temporal dynamics of P outputs; assess changes in P soil pools from European agricultural long-term experiments; and interpret the main causal factors inducing the differences between the observed vs. the simulated pools and fluxes. METHODSWe used data from four long-term experiments to calibrate and test the P submodel of DayCent. The experiments involve five different soils, mineral and organic fertilizer treatments, management intensity levels, various crop rotations, crop residue management, and irrigation. RESULTS AND CONCLUSIONSThe DayCent model captured the gross P budget (input minus output) in the four long-term experiments, and it performed well in simulating their soil total P (PTotal) over time. The model application simulated the soil available P (PAvailable) in the same range as the measured data, but the temporal dynamic did not always match the observed trends. P modelling is subject to a wide range of uncertainties with respect to both input data (particularly the unknown initial distribution of the different pool sizes of P and the uncertainty of the measurements) and the representation of processes influencing the P cycle that are not yet accounted for in the model. Despite these uncertainties and calls for further model assessment and developments, the results show that DayCent was capable of satisfactorily predicting the main P fluxes over time under a wide variety of management practices and European site conditions. SIGNIFICANCEThe model may be used to assess different scenarios with a changing climate, a change in management or land-use, and to analyse potential feedback between the terrestrial and the climate system. This makes this model a promising tool for assessing policy and practical interventions.

Agricultural intensification with seasonal fallow land promotes high bee diversity in Afrotropical drylands

Abstract The exponential increase in the human population in tandem with increased food demand has caused agriculture to be the global‐dominant form of land use. Afrotropical drylands are currently facing the loss of natural savannah habitats and agricultural intensification with largely unknown consequences for bees. Here we investigate the effects of agricultural intensification on bee assemblages in the Afrotropical drylands of northern Tanzania. We disentangled the direct effects of agricultural intensification and temperature on bee richness from indirect effects mediated by changes in floral resources. We collected data from 24 study sites representing three levels of management intensity (natural savannah, moderate intensive and highly intensive agriculture) spanning an extensive gradient of mean annual temperature (MAT) in northern Tanzania. We used ordinary linear models and path analysis to test the effects of agricultural intensity and MAT on bee species richness, bee species composition and body‐size variation of bee communities. We found that bee species richness increased with agricultural intensity and with increasing temperature. The effects of agricultural intensity and temperature on bee species richness were mediated by the positive effects of agriculture and temperature on the richness of floral resources used by bees. During the off‐growing season, agricultural land was characterized by an extensive period of fallow land holding a very high density of flowering plants with unique bee species composition. The increase in bee diversity in agricultural habitats paralleled an increasing variation of bee body sizes with agricultural intensification that, however, diminished in environments with higher temperatures. Synthesis and applications. Our study reveals that bee assemblages in Afrotropical drylands benefit from agricultural intensification in the way it is currently practiced. However, further land‐use intensification, including year‐round irrigated crop monocultures and excessive use of agrochemicals, is likely to exert a negative impact on bee diversity and pollination services, as reported in temperate regions. Moreover, several bee species were restricted to natural savannah habitats. To conserve bee communities and guarantee pollination services in the region, a mixture of savannah and agriculture, with long periods of fallow land should be maintained.

Effects of rye cultivars and management intensity on volatile profile of rye-based spirit distillates

Polish rye grain was cultivated at two levels of management intensity: moderate-input and intensive-input management. Neither the rye cultivar nor the management intensity had a statistically significant effect on the chemical composition of the tested rye grains. The management intensity of rye cultivation did not influence ethanol production. The real yield of absolute ethanol (A100) from 100 kg of the tested rye cultivars was 30.73 ± 0.52 L for KWS Serafino rye grain (intensive management) and 37.14 ± 0.34 L for Antonińskie rye grain (moderate management). However, the concentrations of all volatile compounds in the distillates were significantly affected by the rye cultivar. Management intensity influenced the concentration of almost all carbonyl compounds, excluding acetaldehyde. The differences in the concentrations of esters and higher alcohols were mainly associated with the rye cultivar. The effect of rye cultivar and management intensity, as well as their interactions, influenced the content of methanol and the majority of carboxylic acids.

Biomonitoring via DNA metabarcoding and light microscopy of bee pollen in rainforest transformation landscapes of Sumatra

BackgroundIntense conversion of tropical forests into agricultural systems contributes to habitat loss and the decline of ecosystem functions. Plant-pollinator interactions buffer the process of forest fragmentation, ensuring gene flow across isolated patches of forests by pollen transfer. In this study, we identified the composition of pollen grains stored in pot-pollen of stingless bees, Tetragonula laeviceps, via dual-locus DNA metabarcoding (ITS2 and rbcL) and light microscopy, and compared the taxonomic coverage of pollen sampled in distinct land-use systems categorized in four levels of management intensity (forest, shrub, rubber, and oil palm) for landscape characterization.ResultsPlant composition differed significantly between DNA metabarcoding and light microscopy. The overlap in the plant families identified via light microscopy and DNA metabarcoding techniques was low and ranged from 22.6 to 27.8%. Taxonomic assignments showed a dominance of pollen from bee-pollinated plants, including oil-bearing crops such as the introduced species Elaeis guineensis (Arecaceae) as one of the predominant taxa in the pollen samples across all four land-use types. Native plant families Moraceae, Euphorbiaceae, and Cannabaceae appeared in high proportion in the analyzed pollen material. One-way ANOVA (p > 0.05), PERMANOVA (R² values range from 0.14003 to 0.17684, for all tests p-value > 0.5), and NMDS (stress values ranging from 0.1515 to 0.1859) indicated a lack of differentiation between the species composition and diversity of pollen type in the four distinct land-use types, supporting the influx of pollen from adjacent areas.ConclusionsStingless bees collected pollen from a variety of agricultural crops, weeds, and wild plants. Plant composition detected at the family level from the pollen samples likely reflects the plant composition at the landscape level rather than the plot level. In our study, the plant diversity in pollen from colonies installed in land-use systems with distinct levels of forest transformation was highly homogeneous, reflecting a large influx of pollen transported by stingless bees through distinct land-use types. Dual-locus approach applied in metabarcoding studies and visual pollen identification showed great differences in the detection of the plant community, therefore a combination of both methods is recommended for performing biodiversity assessments via pollen identification.

Combining Landscape Fire Simulations with Stand-Level Growth Simulations to Assist Landowners in Building Wildfire-Resilient Landscapes

The wildfire regime in Portugal has been responsible for millions of hectares of burnt area, and Alvares parish is no exception. In 2017, a severe wildfire burnt 60% of its area. Land abandonment has been increasing since the mid 20th century, and a large fraction of the forest area belongs to quasi-absent landowners. This has given rise to large, almost unbroken expanses of undermanaged forests that, in combination with rugged topography, originates a landscape prone to large, intense wildfires. Thus, a change in landscape composition and structure capable of reducing flammability and promoting fuel discontinuity is urgently needed. A fire spread simulator and a forest growth simulator were combined to show the impact of improving management at landscape level. It was assumed that the probability of large wildfires may be reduced by setting aside forest area for the implementation of a fuel break network (FBN) and increasing the area under sustainable forest management. Three levels of management intensity were simulated by restricting the area of Quasi-absent non-industrial owners to 34.5%, 20.1%, and 8.5% of the Alvares forest area, in favor of increasing the area of active and semi-active non-industrial owners (current, moderate, and high management scenarios). Different FBN extents, representing four levels of network implementation priority were combined with the management levels, resulting in 12 scenarios. To evaluate the impact of fire, simulations assuming no-fire, no-FBN, and current management intensity were performed, whereas the impact of operation costs was assessed assuming reduced costs for silvicultural operations. Per hectare simulations were then scaled up to the parish level and volume harvested and net present values were used to compare the management improvement scenarios. Results showed that fire has major repercussions on forest income, but these impacts can be minimized. Intensifying forest management and implementing the first priority FBN segments originated substantial improvements in financial outcome from timber production, close to those obtained for the full FBN implementation. Results also evidenced contrasting contributions from industrial and non-industrial owners with the later evidencing unbalanced cash-flows derailing the possibility for interesting forest incomes. The coupling of fire and forest growth simulations can be an interesting approach to assess the impact of different management and policy scenarios and inform policies.

Understanding producers' perspectives on rotational grazing benefits across US Great Plains

AbstractExperimental findings on rotational grazing (RG) trials have generally differed from producer observations of RG outcomes on commercial scale ranches. Factors such as small plot size, short duration trials and relatively rigid grazing management that lacks responsiveness to the dynamic and complex social-ecological systems in grazing trials could all contribute to this disparity in outcomes. These differences call for a better understanding of producer perceptions of RG benefits. To fill this knowledge gap, we surveyed 4500 producers from the Northern and Southern Great Plains of the USA. Among the 875 respondents, 40.5% reported that they used continuous grazing (CG), 52.7% implemented RG management in an extensive manner, while 6.8% adopted management intensive grazing. Compared with CG users, adopters of RG in its extensive and intensive form reported an average annual increase of grazing season by 7.6 and 39.3 days, respectively. When controlling for producer demographics, ranch management goals and other rancher characteristics, we found soil and climate heterogeneity significantly affected the perceived relative benefits of RGvsCG strategies. Therefore, instead of focusing on whether RG outperforms CGper se, future research could focus on comparison of RG benefits under different management intensity levels and identifying soil and climate conditions where RG benefits are more noticeable.

Wheat grain and straw yield, grain quality, and disease benefits associated with increased management intensity

AbstractWheat (Triticum aestivum L.) is the third‐most cultivated field crop in the United States and a very important source of nutrition globally. The economic value of wheat motivates farmers to optimize yield and grain quality, which can be obtained with additional inputs that are often expensive. This study investigated three management intensity levels on grain yield, straw yield, grain test weight, and disease on winter wheat in Wisconsin across 4 yr and 20 varieties. All management practices included a pre‐emergence herbicide and N application, with a mid‐level management strategy adding another N application and a single fungicide application to the current strategy, and a high‐level management intensity strategy adding a growth regulator, two micronutrient applications, and another fungicide application to the mid‐level strategy. Our study revealed that increasing management intensity from current strategies to mid‐ or high levels significantly increased grain yields by 0.81–1.22 kg ha−1, straw yields by 1.2–1.2 t ha−1, and grain test weights by 2.6–3.2 kg hl−1, respectively (P < .05). In addition, the high‐level management intensity led to significant reductions in stripe rust incidence and severity, whereas both mid‐ and high‐level management intensity reduced Fusarium head blight incidence and severity, and mycotoxin contamination (P < .001). The economic considerations of intensified management were also examined, and the mid‐ and high‐level management practices resulted in US$306 and US$242 ha−1 greater profit than current management, respectively, as a result of the improved disease protection and yields.

Modelling the effect of accelerated forest management on long-term wildfire activity

We integrated a widely used forest growth and management model, the Forest Vegetation Simulator, with the FSim large wildfire simulator to study how management policies affected future wildfire over 50 years on a 1.3 million ha study area comprised of a US national forest and adjacent lands. The model leverages decades of research and development on the respective forest growth and wildfire simulation models, and their integration creates a strategic forest landscape model that has a high degree of transparency in the existing user communities. The study area has been targeted for forest restoration investments in response to wildland fires that are increasingly impacting ecological conditions, conservation areas, amenity values, and surrounding communities. We simulated three alternative spatial investment priorities and three levels of management intensity (area treated) over a 50-year timespan and measured the response in terms of area burned, fire severity, wildland-urban interface exposure and timber production. We found that the backlog of areas in need of restoration on the national forest could be eliminated in 20 years when the treatment rate was elevated to a maximum of 3× the current level. However, higher rates of treatments early in the simulation created a future need to address the rapid buildup of fuels associated with understory shrub and tree regeneration. Restoration treatments over time had a large effect on fire severity, on average reducing potential flame length by up to 26% for the study area within the first 20 years, whereas reductions in area burned were relatively small. Although wildfire contributed to reducing flame length over time, area burned was only 16% of the total disturbed area (managed and burned with prescribed fire) under the 3× management intensity. Interactions among spatial treatment scenarios and treatment intensities were minimal, although inter-annual variability was extreme, with the coefficient of variation in burned area exceeding 200%. We also observed simulated fires that exceeded four times the historically recorded fire size. Fire regime variability has manifold significance since very large fires can homogenize fuels and eliminate clumpy stand structure that historically reduced fire size and maintained landscape resiliency. We discuss specific research needs to better understand future wildfire activity and the relative influence of climate, fuels, fire feedbacks, and management to achieve fire resiliency goals on western US fire frequent forests.

Positive outcomes between herbivore diversity and tree survival: Responses to management intensity in a Patagonian forest

Sustainable forest management aims to both enhance biodiversity and tree productivity. However, trade-offs may exist between these objectives, e.g. arthropod diversity and associated arthropod herbivory can reduce tree growth and survival. Tree productivity and biodiversity may also show non-linear responses to management intensity, making applied recommendations even more challenging. We studied the effects of harvesting intensity for firewood extraction in a northern Patagonian forest (Argentina) on leaf damage diversity (as a proxy of arthropod folivore diversity), leaf damage frequency, growth and survival of planted trees of Nothofagus obliqua for timber purpose. We randomly applied four levels of harvesting intensity (0, 30, 50, and 70% of basal area removal) in experimental plots and we followed the responses on the focal planted tree species during two growing seasons. After harvesting, air temperature and photosynthetic active radiation increased, while relative humidity decreased, with harvesting intensity. Leaf damage diversity and frequency showed non-linear responses to harvesting intensity, both achieving its highest values at intermediate harvesting intensities (30% and 50% of basal area removal). Such responses were consistent for contrasting feeding guilds, using different diversity indices, and during the two study growing seasons. Interestingly, leaf damage diversity and frequency were positively and strongly correlated across the plots. Despite great leaf damage frequency (around 45% of the leaves were damaged), plant survival was also highest at intermediate harvesting intensities during the two years. Planted trees also grew more at intermediate harvesting intensities during the second year, but increased linearly with harvesting intensity during the first year. Hence, at intermediate harvesting intensity, no trade-off was observed between arthropod biodiversity and planted tree sapling survival and growth. In northern Patagonia, trees may face less competition for light and soil resources at intermediate harvesting intensities, while at high harvesting intensities water stress typical of dry Patagonian summers could reduce tree survival. Such benefits were not offset by the greater leaf damage (associated with enhanced damage diversity) observed at intermediate harvesting intensities. Therefore, intermediate levels of management intensity can provide the double service of increasing arthropod diversity and maximizing tree survival and growth, especially during the most critical establishment period.

The Contribution of Functional Traits to the Breeding Progress of Central-European Winter Wheat Under Differing Crop Management Intensities.

Wheat yields in many of the main producing European countries stagnate since about 20 years. Hence, it is of high interest, to analyze breeding progress in terms of yield and how associated traits changed. Therefore, a set of 42 cultivars (released between 1966 and 2012) was selected and yield as well as functional traits defined by the Monteith and Moss equation were evaluated under three levels of management intensity. The Monteith Moss equation thereby calculates grain yield as the product of incident photosynthetically active radiation, fraction of intercepted radiation, radiation use efficiency, and harvest index. The field trial was performed in a high yielding environment in Northern Germany in two seasons (2016–2017 and 2017–2018) with very contrasting rainfall rates. The three differing managements were: intensive (high N + pesticides), semi-intensive (high N − pesticides), and extensive (low N − pesticides). The results indicate that the stagnation of wheat yields in Central-Europe is not caused by a diminishing effect of breeding on yield potential. This equally applies to suboptimal growing conditions like extensified crop management and restricted water supply. Nearly all functional sub-traits showed a parallel progress but coefficients of determination of relationships between traits and year of variety release are decreasing along the hierarchy of yield formation. One exception is radiation interception which did not show a stable linear increase during breeding history. In recent years, biomass is getting more important in comparison to harvest index. Values of harvest index are slowly approaching theoretical maxima and correlations with grain yield are decreasing.

Ecologically similar saproxylic beetles depend on diversified deadwood resources: From habitat requirements to management implications

Organisms dependent on dead wood (i.e., saproxylic) are some of the most threatened by changes in the forest environment. Aside from anthropogenic disturbances resulting in forest fragmentation and a decrease in dead wood, the expansion of homogenous closed-canopy forests due to successional changes is identified as the main threat for many saproxylic organisms. It is especially important in major conservation areas in Europe. Thus, studies combining knowledge about the habitat requirements of saproxylic species with the impacts of different types of forest management on populations of these organisms are essential to identify effective conservation strategies.In this study, we focused on three threatened saproxylic beetles with similar ecology, i.e., Cucujus cinnaberinus, C. haematodes and Boros schneideri, in a close-to-natural forest. The study was conducted in the stronghold of these species in temperate Europe, the Białowieża Forest in Poland, based on a field survey of more than 11,000 dead wood pieces. We investigated the habitat requirements of these species and their relationships with the environment at the tree and landscape levels. We further analysed the distribution of these beetles in forests under various levels of management intensity. Based on the results of the present study and published data on compositional changes in the forests in the study area, we attempt to formulate implications related to the conservation of the studied beetles.Cucujus cinnaberinus was the most widespread and frequent species, with a preference for high-diameter dead aspens in managed forests with high dead wood amounts. The second most abundant species, C. haematodes, preferred downed ashes and alders with rather fragmented bark. Its distribution was spatially aggregated in unmanaged forests. The rarest beetle in this study, B. schneideri, was associated with forests with large dead pines.Our results confirm the importance of the Białowieża Forest for the three threatened saproxylic beetles. The study also revealed the highly diversified demands of these beetles, which may not be met in the future if the abundance of the preferred habitat tree species is declining. We recommend a conservation strategy that combines non-intervention towards naturally developed deadwood with monitoring of tree recruitment and if necessary, measures to assure recruitment of particular tree species, e.g., pine and aspen. Future studies should investigate the role of natural disturbances for recruitment of these tree species and thus, the long-term persistence of associated saproxylic beetle species.

Optimisation of the conservation of rare and vulnerable plant species in the perspective of climate change in Lithuanian (nature) reserves

Abstract Nature reserves are one of the most important measures in saving biodiversity, however, during the climate change, a real danger arises, that these territories would not be able to fulfill the objectives. In order to mitigate negative effects of climate change in protected areas it is necessary to create and apply management programs, based on future ecosystems needs. The main aim of presented study was to evaluate sensitivity of rare and vulnerable species to climate change in order to suggest measures for better management of nature reserves in the future. According to scientific literature, 12 biological and ecological plant characteristics determining sensitivity of species (limiting factors) have been detected. 73 plant species that are protected in Lithuanian reserves were evaluated qualitatively according to limiting factors of climate change. As the result, it was offered to apply additional protection measures to 47 species in the light of climate change. Groups of plant species that should be affected highly negatively or highly positively were identified. 16% of plant species protected in nature reserves were evaluated as very sensitive to climate change and the condition of these plants may worsen. On the other hand, 14 plant species were given as least sensitive to negative effects and future climate is more favorable to species growth and spread than the existing. The highest danger is predicted for Silene chlorantha (Willd.) Ehrh., and the best condition is predicted for Mentha longifolia (L.) Huds. Dactylorhiza incarnata (L.) Soó. The study also gives recommendations for the protection of rare plants in the future. Different management measures are taken into account: mitigation of the direct effect of climate change (I), improvement of an existing level of rareness (II), respecting the relation to physical and biological environment (III), consideration of spread and geographical limits (IV). Three management intensity levels were suggested according to species sensitivity.

Enhancing the soil and water assessment tool model for simulating N2O emissions of three agricultural systems

Nitrous oxide (N2O) is a potent greenhouse gas (GHG) contributing to global warming, with the agriculture sector as the major source of anthropogenic N2O emissions due to excessive fertilizer use. There is an urgent need to enhance regional‐/watershed‐scale models, such as Soil and Water Assessment Tool (SWAT), to credibly simulate N2O emissions to improve assessment of environmental impacts of cropping practices. Here, we integrated the DayCent model's N2O emission algorithms with the existing widely tested crop growth, hydrology, and nitrogen cycling algorithms in SWAT and evaluated this new tool for simulating N2O emissions in three agricultural systems (i.e., a continuous corn site, a switchgrass site, and a smooth brome grass site which was used as a reference site) located at the Great Lakes Bioenergy Research Center (GLBRC) scale‐up fields in southwestern Michigan. These three systems represent different levels of management intensity, with corn, switchgrass, and smooth brome grass (reference site) receiving high, medium, and zero fertilizer application, respectively. Results indicate that the enhanced SWAT model with default parameterization reproduced well the relative magnitudes of N2O emissions across the three sites, indicating the usefulness of the new tool (SWAT‐N2O) to estimate long‐term N2O emissions of diverse cropping systems. Notably, parameter calibration can significantly improve model simulations of seasonality of N2O fluxes, and explained up to 22.5%–49.7% of the variability in field observations. Further sensitivity analysis indicates that climate change (e.g., changes in precipitation and temperature) influences N2O emissions, highlighting the importance of optimizing crop management under a changing climate in order to achieve agricultural sustainability goals.

Solitary trees increase the diversity of vascular plants and bryophytes in pastures

Wooded pastures are semi-natural ecosystems that are often considered biodiversity hotspots and are valuable for nature conservation. Ongoing land-use changes, such as management intensification, threaten these ecosystems. Several studies have assessed the effect of tree density and cover on plant species richness, but the individual effects of single trees have not been addressed previously. We studied the effects of single sycamore maple trees (Acer pseudoplatanus) in sycamore maple wooded pastures on vascular plant and ground bryophyte species richness at six sites in the northern European Alps. In total, we found 346 vascular plant species and 264 bryophyte species. Alpha- and beta-diversity were positively influenced by the trees and positively related to tree size- and tree age-related variables. The positive effect of the trees on the species richness of epigeic bryophytes was reduced at high levels of management intensity, possibly due to severe disturbance by cattle trampling under the trees. However, our data showed that the diversity of the ground vegetation increased when trees were present, even in intensively managed pastures. Our findings highlight the high species richness present in sycamore maple wooded pastures at different spatial scales. The trees in sycamore maple wooded pastures can thus be considered keystone structures providing a range of important functions and conservation policies should particularly emphasize the conservation of large and old trees as well as the planting of young trees in these ecosystems.

A survey method for assessing the richness of epiphytic lichens using growth forms

The species richness of epiphytic lichens is continuously decreasing by degradation and loss of habitat. Considering that taxonomic identification of all species is time and resource consuming, rapid assessment methods to extrapolate the total number of species are needed for practical conservation. This paper describes an alternative method using the correlation between lichens growth forms and species richness. The study was conducted in 406 forest stands located in Central Spain, covering a wide range of mediterranean-climate ecosystem regions, management intensity levels, canopy cover conditions, and tree sizes. The presence/absence of epiphytic lichens was determined in 6090 trees, which were dominated by oak species (Quercus ilex, Q. faginea, and Q. pyrenaica). In all type of forests, the diversity of growth forms was positively correlated with the total epiphytic lichen richness. In all cases, species richness increased in non-managed forest stands with dense canopies. Thus, we propose the use of lichen growth forms as a helpful surrogate of species richness to detect potentially conservation priority areas in the Mediterranean region.

Community composition and activity of insectivorous bats in Mediterranean olive farms

AbstractOlive (Olea europaea L.) farming is one of the most widespread agricultural practice throughout the Mediterranean basin. Current trends even predict an increase in land area devoted to olive farms as well as the intensification of farming practices. However, knowledge of the effects of olive farming on animal species still remains elusive and conservation and management guidelines for the relevant stakeholders are therefore urgently needed. Here, we investigate community composition and activity patterns of insectivorous bats in Mediterranean olive monocultures in Southern Portugal. Bats surveys were carried out in three types of olive farms representing increasing levels of management intensity: (1) traditional olive farms, managed with few or no chemical inputs or manual labor; (2) semi‐intensive olive farms, which share certain characteristics with traditional plantations, but are more intensively managed; (3) intensive olive farms, which are managed with high and frequent chemical inputs, and highly mechanized systems. We found differences in species richness and activity levels between farming practices. Both the number of species and foraging activity declined with increasing management intensity. However, olive groves as a whole showed a lower number of species compared with the regional species pool and extremely low activity levels, suggesting that large and homogeneous olive monocultures may serve more as commuting areas than true foraging habitats for bats. To our knowledge, this is the first study explicitly demonstrating the pervasive impact of olive farming on the community composition and activity levels of insectivorous bats. In the face of an even‐increasing proportion of land surface devoted to olive farming in Mediterranean landscapes, our findings are therefore of great concern. We suggest that increasing habitat heterogeneity would contribute to preserve the community composition and ecological functionality of insectivorous bats in extensive olive monocultures.

The effects of household management practices on the global warming potential of urban lawns

Nitrous oxide (N2O) emissions are an important component of the greenhouse gas (GHG) budget for urban turfgrasses. A biogeochemical model DNDC successfully captured the magnitudes and patterns of N2O emissions observed at an urban turfgrass system at the Richland Creek Watershed in Nashville, TN. The model was then used to study the long-term (i.e. 75 years) impacts of lawn management practice (LMP) on soil organic carbon sequestration rate (dSOC), soil N2O emissions, and net Global Warming Potentials (net GWPs). The model simulated N2O emissions and net GWP from the three management intensity levels over 75 years ranged from 0.75 to 3.57 kg Nha−1yr−1 and 697 to 2443 kg CO2-eq ha−1yr−1, respectively, which suggested that turfgrasses act as a net carbon emitter. Reduction of fertilization is most effective to mitigate the global warming potentials of turfgrasses. Compared to the baseline scenario, halving fertilization rate and clipping recycle as an alternative to synthetic fertilizer can reduce net GWPs by 17% and 12%, respectively. In addition, reducing irrigation and mowing are also effective in lowering net GWPs. The minimum-maintenance LMP without irrigation and fertilization can reduce annual N2O emissions and net GWPs by approximately 53% and 70%, respectively, with the price of gradual depletion of soil organic carbon, when compared to the intensive-maintenance LMP. A lawn age-dependent best management practice is recommended: a high dose fertilizer input at the initial stage of lawn establishment to enhance SOC sequestration, followed by decreasing fertilization rate when the lawn ages to minimize N2O emissions. A minimum-maintained LMP with clipping recycling, and minimum irrigation and mowing, is recommended to mitigate global warming effects from urban turfgrass systems. Among all practices, clipping recycle may be a relatively malleable behavior and, therefore, a good target for interventions seeking to reduce the environmental impacts of lawn management through public education. Our results suggest that a long-term or a chronosequence study of turfgrasses with varying ages is warranted to capture the complete dynamics of contribution of turfgrasses to global warming.

Indices for quantitative evaluation of soil quality under grassland management

ObjectiveThe objectives of this study are to determine appropriate indicators, the most appropriate scoring function (linear or non-linear) and integrating procedure (additive and weighted additive) for a soil quality index for typical temperate, maritime grassland management (e.g. livestock grazing and silage production). MethodsThe study was conducted on twenty grassland sites classified by three levels of management intensity. Twenty-one soil properties were measured as potential indicators of soil quality, and the visual evaluation of soil structure was applied to select indicators responsive to management and for the validation of the indices. Indices were calculated using linear and non-linear scoring, followed by additive and weighted additive integration. Principal component analysis used with the total dataset of indicators sensitive to management to determine a minimum dataset. ResultsSoil organic carbon (SOC), total nitrogen, aggregate size distribution, bulk density, bulk density of ≤2mm fraction, extractable potassium and carbon–nitrogen ratio (CN) were the indicators that comprised the total dataset, while SOC, CN and bulk density of ≤2mm fraction were the minimum dataset. The management intensity influenced each indicator in different ways, and the index calculated using minimum dataset and nonlinear weighted additive integration had the best discrimination ability. ConclusionsThe average soil quality index values were lower under higher intensity management, and indicated that management intensification was tending toward an adverse impact on soil quality under grassland systems in Ireland. PracticeThere was no evidence that current grassland management was having a long-term detrimental effect on soil quality for grassland production, but the trend suggested that increasing intensity might cause management difficulties due to soil limitations in the future. ImplicationsThe indexing approach in this study provides a practical, time and cost effective method for quantitative evaluation of soil quality under temperate maritime grassland management.

Revealing N management intensity on grassland farms based on natural δ15N abundance

High application rates of farmyard manure on grasslands generally results in nitrogen (N) losses and a shift in N isotope composition. The aim of this study was to elucidate to which degree the 15N signatures of miscellaneous N pools at two different levels of management intensity may be used to reproduce the N level of various grassland farms in practise, i.e. beyond the control of experimental plots. We hypothesized that (i) higher δ15N values in soil, plant and animal samples can be found with intensified grassland farming and high N-input management, (ii) that the 15N signature originating from manure application is influenced by application technique and (iii) that it declines with increasing distance from stable to field. To test these hypotheses, we monitored different N pools on nine different farms (dairy, suckler, beef production) in grassland dominated regions of North Rhine-Westphalia, Rheinland-Palatinate (Germany) and Styria (Austria). Samples were taken from 0 to 5cm soil depth and aboveground biomass at each of five sub-sites on farm, as well as from feed components, fertilizers, and cattle product and tissue like milk, hair, faeces and urine.The results indicated a considerable variation in δ15N values of the top soil (1.47‰ to 7.91‰) and of harvested plant material (−2.18‰ to 6.79‰). On average, δ15N values of samples from high N-input grasslands were elevated by 2.8 delta units relative to those of low N-input grasslands. For the soil and plant samples, the δ15N values were thus closely correlated with the overall N balance as well as with stocking rate and fertilizer input (r2=0.71 to 0.85). Respective trends for the isotopic signatures in milk, hair and faeces were also evident but less apparent. Furthermore, low emission application techniques of organic fertilizer and increasing distances from the stable to the field exhibited lower δ15N values of top soils and plants, but only in the low input system. We conclude that high N-input on grassland farms systematically changes the δ15N values of soils and above ground biomass and thus also the N signature in animal tissues. Application of N isotope technique to these N pools thus allows for tracing back intensity of fertilizer management regardless of high natural δ15N variations in terrestrial environments.