Management Mowing Research Articles

Why mow?: A review of the resulting ecosystem services and disservices from mowing turfgrass

AbstractTurfgrasses are those grasses that tolerate frequent mowing. The act of mowing turfgrasses, primarily lawn mowing, has received much negative attention primarily due to its labor requirement and the resulting mower emissions. This paper provides a comprehensive review of the benefits and drawbacks of mowing grasses, specifically turfgrasses used on lawns, parks, golf courses, and sports fields, using an ecosystem services and disservices framework. Discussed is the challenge of creating a “one‐size‐fits‐all” approach to selecting the best mowing management practices and sociocultural tensions that exist related to lawn mowing. Discussion also includes the benefits and value gained from mowing turfgrass and strategies to mitigate ecosystem disservices that result from mowing.

Mechanical mowing of semi‐natural grasslands compromises soil quality and survival of a conservation target plant species

Mowing is a crucial management strategy for conservation and restoration of semi‐natural grasslands. In the past decades, dominant mowing methods have changed from manual to mechanical, using heavy machines causing soil compaction. Whereas the negative effects of compaction are well understood in agriculture and forestry, they have received little attention so far in nature management. This study aims to investigate the effects of compaction on soil quality, arbuscular mycorrhizal fungal communities, and survival of a target plant species. We subjected seven grasslands to three contrasting mowing types: manual mowing with a brush cutter, softtrack mowing—designed to minimize soil compaction—and tractor mowing. We compared compaction, soil properties, and arbuscular mycorrhizal communities among the types. Additionally, we experimentally subjected intact grassland sods containing Devil's bit scabious (Succisa pratensis Moench), a target species of grassland conservation, to compaction levels corresponding to the three mowing types. Subsequently, we assessed plant survival. We found that soil compaction, soil nutrient availability, and toxic soil elements were significantly higher in the softtrack‐ and tractor‐mown parts of grassland sites compared to the manually mown parts. Also, the arbuscular mycorrhizal community composition differed significantly among mowing types, with the largest differences between “manual” and “tractor.” Succisa pratensis survival significantly decreased by 43 and 71% on the short term and by 71 and 86% on the longer term with increasing compaction. Consequently, mowing‐associated soil compaction compromises nature management targets via at least four mechanisms: nutrient enrichment, soil toxicity, changes in arbuscular mycorrhizal communities, and decreased survival of the target plant species.

Fast grassland recovery from viable propagules after reintroducing traditional mowing management on a steep slope

Semi-natural grasslands on steep slopes often show high plant species diversity. These grasslands were traditionally maintained through mowing and/or grazing. The traditional management practices help to maintain species diversity, whereas land abandonment reduces diversity by increasing competition from dominant species and reducing seedling recruitment. The reintroduction of management can reverse species diversity declines, but suitable grassland restoration programs are scarce in Japan. To study the effect of short-term abandonment on seedling ecology, we monitored the vegetation of a Susogari grassland that had been abandoned for 3 years; the grassland occupies a steep slope (ca. 50°) on a hillside above paddy fields, and was traditionally mown. We monitored the vegetation before abandonment, in the 3rd year of abandonment, and in the 1st and 2nd years after restoration of mowing management. Emergence and survival of seedlings was monitored for 18 months after reintroduction of management. We monitored 1,183 seedlings of grassland species and non-target annuals in ten 1-m2 plots. After mowing was reintroduced, most grassland species reappeared or increased in the first and second years. Few seedlings of perennial plants and no seedlings of annuals flowered. An exotic species, Solidago altissima, had a lower survival rate (10%) than grassland species (>30%), and all but two grassland species survived over the 18-month period. Although vegetation composition was not fully recovered, our findings suggest that a steep slope acts as a strong filter that inhibits the establishment of non-target species while enhancing persistence of target grassland species.

Assessment of the Effects of Autonomous Mowers on Plant Biodiversity in Urban Lawns

Gaining information on the impact of lawn management with autonomous mowers on the floristic composition is crucial to improve their plant biodiversity. In this study, an autonomous mower with a reduced mowing frequency and a more sporadic mowing management system with a ride-on rotary mower were compared in terms of the effect on three dicotyledonous species (Phyla nodiflora, Lotus corniculatus and Sulla coronaria) transplanted onto stands of Bermuda and Manila grass. Regardless of the management system, P. nodiflora achieved the best results in terms of survival for both lawns (74.92 and 58.57% in Manila and Bermuda grass, respectively). In Bermuda grass, a higher percentage of surviving individuals was observed for the ordinary mower management system (42.59%), rather than with the autonomous mower (9.10%), while no differences emerged on Manila grass. On both Manila and Bermuda grass, a higher average percentage of coverage for single individual was observed for the ordinary mower management system (1.60 and 0.37%, respectively) compared to the autonomous mower system (0.55 and 0.08%, respectively). P. nodiflora had a higher percentage of individuals with flowers with the ordinary management system rather than with autonomous mower system both on Manila (60.73% and 33.90%, respectively) and Bermuda grass (48.66 and 3.32%, respectively). Despite a lower impact on the planted species being observed for the ordinary mower management system, encouraging results were obtained with the autonomous mower, for instance regarding the percentage of surviving individuals for P. nodiflora (33.95%) and L. corniculatus (22.08%) on Bermuda grass and the percentage of individuals with flowers for the same two species (33.90 and 13.59%, respectively) on Manila grass. Furthermore, the autonomous mower management system’s primary energy consumption over the year was lower compared to that of the ordinary system both on Manila (200.4 and 614.97 kWh ha−1 year−1, respectively) and Bermuda grass (177.82 and 510.99 kWh ha−1 year−1, respectively).

Nature by prescription

Az groeninge hospital is located in an extensive nature domain. With the 'nature on prescription' project, the hospital brings patients, visitors, employees, and residents closer to nature. And to each other.
 The project is a collaboration with the city of Kortrijk, Doerak, Intercommunale Leiedal, Natuurpunt, Stadlandschap Leie en Schelde, Province of West-Flanders and Agency for Nature and Forest.
 It has been proven: nature has an important influence on our health. Fifteen minutes of nature a day is enough to lower the stress hormone cortisol. Depressive feelings are also reduced if you get out into nature. In addition, exercise in green spaces stimulates social interaction with others.
 This project ensures that the urban green reserve Marionettes, the Kennedy forest and the green area around the hospital can maximize their added value for visitors, patients, employees, and the local community. Doctors can prescribe a walk in nature. Waiting during consultations takes less time if you can get outside for a moment.
 Nature in your neighborhood. Something for everyone
 Az groeninge's garden is split into different zones with various thematic corners. The area around Zibi's tree house - a therapy room for children - is a zone where biodiversity is encouraged by smart mowing management. Other areas of grass remain untouched so that nature can take its course.
 Attached to the House of Movement are an orchard and a meadow where donkeys are at home. Animals are often a good distraction and are also used during therapy sessions. Care greenery in the context of therapy works on the state of mind. Patients find peace and distraction.
 Employees of az groeninge who are also beekeepers take care of bees in the bee hotel in their spare time. Those bees also provide delicious az groeninge honey.
 A visit to the hospital is often an unpleasant experience for children. An obstacle course is set up in the courtyard, we have a climbing wall adapted for children and the educational center "Doerak" near the hospital organizes various activities.
 The Koesterplek
 From the rainbow garden with all kinds of ecologically grown flowers, a path leads to the place where we cherish our lost ones. Here people can retreat into nature to remember someone. People can leave a message in a locked mailbox or hang a name disc in the tree as a voice of remembrance.
 Theme routes
 Through an app or the website, people can also follow a number of interactive routes around different themes such as stress reduction and children's yoga.
 Everyone Welcome
 Through integrated cooperation with different partners, we have succeeded in connecting people with nature and with each other: not only patients, visitors, and employees from the neighborhood but also residents from the region are welcome. Each partner has placed accents in the project from its own core business. Care, nature conservation, education and experience go hand in hand.
 Nature is good for body and mind. With "nature by prescription" we open the door to our gardens. Everyone is always welcome! Even without a prescription.

Behavioral Analysis of Mowing Workers Based on Hilbert–Huang Transform: An Auxiliary Movement Analysis of Manual Mowing on the Slopes of Terraced Rice Fields

In the mountainous areas of Japan, the weeds on the slopes of terraced rice paddies still need to be cut by the elderly manually. Therefore, more attention should be given to maintain proper postures while performing mowing actions (especially the pre-cutting actions) to reduce the risk of accidents. Given that complex mowing actions can be decomposed into different sub-actions, we proposed a joint angular calculation-based body movement analysis model based on the Hilbert–Huang transform to analyze the pre-cutting actions. We found that the two most important sub-actions were fast pre-cutting and slow pre-cutting. Based on field experiments, we analyzed the pre-cutting actions of workers with different experience levels and identified the factors that affected their falling risk (stability). The results showed differences and similarities in the actions’ frequency and amplitude in the sub-actions of workers with different mowing experience, confirmed the influence of body characteristics (body height, etc.) on body stability, and showed that workers should pay attention to their age and ankle part while mowing. The analysis results have identified factors for the mowing workers’ training and the development of equipment for use in complicated geographical conditions.

DIRECT SEEDING FOR RESTORATION IN TABULEIRO FORESTS: EVALUATION 16 YEARS AFTER IMPLEMENTATION

This study was carried out at the Vale Natural Reserve in Linhares, Espírito Santo, Brazil, with the objective of testing the use of direct seeding as a forest restoration method in Tabuleiro Forest (also called Tableland Forest outside of Brazil) 16 years after its implantation. Three different treatments were evaluated in which 29 native species with different area preparations were used, namely: Total manual mowing + residue burning + herbicide (T1); Total manual mowing + residue burning (T2); and Total manual mowing (T3). Each treatment had an area of 100m² (10x10m) and an interval between plots of 2 m. The survival of the individuals implanted in the direct seeding was evaluated, as well as the natural regeneration of the new individuals with Diameter at Breast Height (DBH) = 15 cm. As a result, after 16 years we can see the presence of 16 species and 106 individuals, as well as a Shannon’s diversity index of (H’) = 1.917 and Pielou’s index (P) = 0.691, demonstrating a low floristic diversity in the area. The species which stood out the most (most individuals) were: Joannesia princeps Vell. L.C.; Spondias venulosa (Engl.) Engl.; and Peltophorum dubium (Spreng.) Taub. As a suggestion, it is recommended to use direct seeding in a complementary manner to other restoration techniques, and there should be monitoring of the area in order to assess the evolution of the process and the need for any interventions to assertively assist the entire process.

Responses of soil microorganisms, enzyme activities and nutrient contents to inter-row grass ploughing and returning to the field in a natural sod culture apple orchard.

Natural sod culture in orchard is an effective measure to improve the orchard productivity and promote the sustainable production. To explore the effects of inter-row grass ploughing and returning on soil biological cha-racteristics and nutrient contents, we examined the effects of different grass returning to the field on the amount of soil microorganisms, enzyme activities and nitrogen and potassium contents of 0-20 cm soil layer. There are three treatments, cleaning tillage as the control (CK), conventional mowing management (NG), and soil ploughing annually under natural sod culture with conventional mowing condition (NGR) treatments. The results showed that soil microorganisms were dominated by bacteria, followed by actinomycetes, with the least fungi. Compared with CK, both NG and NGR treatments significantly improved the abundance of soil bacteria and fungi, with the strongest effects in NGR treatment, and significantly increased the soil urease, sucrase and catalase activities by 59.0%, 20.7%, 38.3% and 73.5%, 45.9%, 67.8%, respectively. NGR treatment significantly increased soil nitrogen and potassium contents, with the contents of ammonium nitrogen, nitrate nitrogen, particulate organic nitrogen, microbial biomass nitrogen, available potassium and water-soluble potassium being 1.5, 1.8, 1.6, 2.0, 1.3 and 1.4 times of that in CK, respectively. NGR significantly increased soluble sugar content and sugar acid ratio and subsequently improved fruit quality. Overall, NGR increased soil microbial abundance, enzyme activities, nitrogen, potassium contents and fruit quality, which could be a feasible management of inter-row grasses in the natural sod culture apple orchard.

Biological quality and organic matter dynamics in minesoil at 18 years reclamation with perennial grasses

Mining is one of the most destructive economic activities on natural ecosystems. There are around 750 ha impacted by open-pit coal mining in Candiota Mine, the largest in Brazil, with 1.2 billion tons subject to mining. In soils impacted by mining, litter decomposition, always linked to a more extended period of restoration and maintenance of the vegetation, presents positive correlations with the diversity of the edaphic fauna and the enzymatic activity of these areas, promoting improvements in the ecological functions of the new ecosystem. The objective of the present study was to analyze the impact of revegetation with different summer perennial grasses subjected to different mowing managements on the biological and chemical quality of soils after coal mining in an experimental area at the Candiota Mine. Analyzes were performed to identify edaphic organisms using modified Berlese-Tüllgren funnels and microbiological analyzes to quantify Microbial Biomass Carbon (MBC), Microbial Respiration (MR), and urease enzymatic activity. The different fractions of Soil Organic Matter (fulvic, humic acids, and humin) were also quantified to understand the degree of humification in the area. All results were compared in mean tests by Tuckey's test (p < 0.05) and by Principal Component Analysis. After 18 years of revegetation and 11.6 years of mowing management in the area, there was an improvement in MBC and MR compared to the Control, evidencing the positive effect of the perennial grasses used in the experimental area. However, mowing management cannot yet be considered the most promising management for improving edaphic conditions.

Mowing Increases Root-to-Shoot Ratio but Decreases Soil Organic Carbon Storage and Microbial Biomass C in a Semiarid Grassland of North China

Quantifying the long-term effects of mowing on soil organic carbon (SOC) is of great importance for understanding the changes in the carbon cycle of the grassland ecosystem and for managing the grassland strategies for both production and soil nutrients. We investigated SOC content and storage within the 0–30 cm soil layer in the grasslands following the application of different mowing regimes—i.e., mowing once every 2 years (M1/2), mowing twice every 3 years (M2/3), mowing once a year (M1/1), mowing twice a year (M2/1), and no mowing (CK)—in the semiarid steppe of northern China. The results indicated that SOC storage and microbial biomass C (MBC) decreased significantly with soil depth. Different mowing frequencies all declined SOC storage and MBC of the grassland ecosystem; however, the root-to-shoot ratio (R:S) was increased. The SOC storage was greatest under CK and had the following order: CK &gt; M1/2 &gt; M2/3 &gt; M1/1 &gt; M2/1 at 0–20 cm, while no significant difference existed in the five mowing frequencies at the soil 20–30 cm layers. Our findings elucidate that different mowing regimes influence soil carbon storage by altering the productivity of vegetation, litter, plant community composition, soil microbial biomass, and resource allocation between aboveground plants and belowground roots, which need to be considered in the sustainable utilization of grasslands in the future. The results of this study support the view that mowing once every 2 years may be an effective mowing management regime for semiarid grasslands, as it conserves both above and belowground parts and maintains the healthy development of ecosystem functions in semiarid grasslands.

Response of soil carbon fractions and enzyme activities to mowing management on in a coastal wetland of the yellow river delta

Coastal wetlands are considered as important “blue carbon” sink, and mowing management induced by anthropogenic activities is anticipated to profoundly affect soil carbon stocks in coastal wetlands. However, the impacts of mowing management on soil organic carbon (SOC) and enzyme activities and the mechanisms responsible for associated changes in Phragmites australis wetland remain uncertain. We conducted a field mowing manipulation experiment [control (CK), mowing and returning straw in December (12MS), mowing and removing straw in December (12MR), mowing and returning straw in March (3MS), and mowing and removing straw in March (3MR)] in P. australis wetland of the Yellow River Delta and quantified their impacts on soil quality, SOC, SOC fractions, and enzyme activities. Results showed that mowing treatments led to overall increases in soil nutrients [total carbon (TC), total nitrogen (TN), total phosphorus (TP), NH4+, and NO3−] and decreases in soil C/N ratio. The effects of mowing treatments on soil nutrient content were pronounced on topsoil than deep soil, and the maximum value of TC, TN, and TP reached in the 12MR treatment. Compared with CK, the 12MS, 12MR, 3MS, and 3MR treatments at 0–10 cm depth significantly enhanced SOC content by 8.78%, 32.9%, 16.5%, and 30.1%, respectively, but only the 3MS treatment enhanced SOC by 16.5% at 10–20 cm depth. Mowing treatments increased dissolved organic carbon (DOC), microbial biomass carbon (MBC), particulate organic carbon (POC), and labile organic carbon (LOC) and the contents of DOC, MBC, POC, and LOC decreased with soil depth. Mowing treatments stimulated the activities of sucrase and urease in topsoil, but only the 3MR treatment improved alkaline phosphatase activity in topsoil. Path analysis indicated that mowing management dominantly modulates SOC by changing sucrase activity, alkaline phosphatase activity, TN, TP, NH4+, NO3−, DOC, and LOC in 0–10 cm depth. However, SOC was significantly controlled by sucrase activity, urease activity, TC, TN, TP, LOC, and POC in 10–20 cm depth. Collectively, our results indicate that the continuous mowing management is beneficial to enhance soil quality and carbon storage capacity of P. australis wetlands, which will contribute to enhance carbon sequestration and sink capacity of coastal wetlands.

ROBO‐GOLF: Robotic mowers for better turf quality on golf courses—Preliminary results

AbstractSince 2020, the Norwegian Institute of Bioeconomy (NIBIO) Turfgrass Research Group has been studying agronomic, environmental, and economic consequences of switching to light‐weight robotic mowers on golf course fairways and semiroughs. Preliminary results from field trials in 2020 and 2021 at the NIBIO Turfgrass Research Center Landvik, Norway, and demonstration trials on one golf course in each of the five Nordic countries, showed that turfgrass quality with robotic mowing was similar to manual mowing. At Landvik, robotic mowing resulted in less disease in both fairway and semirough but more infestation of white clover than manual mowing in the semirough. A survey of players’ attitudes to robotic mowers conducted on the five golf courses showed that about 90% of the players were positive or neutral to the new technology. However, respondents asked for better adaptation of the local rules on the golf course and even the international rules of golf to robotic mowing.

Can mulch be effective in controlling exotic grasses and promoting natural regeneration in ecological restoration?

Mulching use in agriculture has been known since 1802 as the practice of spreading dry leaves and straw on the soil to prevent erosion and water loss. Our study evaluated the mulch effectiveness in the establishment of regenerating seedlings and its contribution to the control of exotic grasses. The studies were carried out in an ecological restoration area in the municipality of Itapira-SP. The treatment with mulching consisted in chemical desiccation with glyphosate herbicide application, keeping the dry grass on the ground. In the control treatment, after chemical weeding, the grass was removed with manual mowing, exposing the soil. Eight months after implantation, we sampled all regenerating seedlings in 100 plots of 50 x 50 cm in each treatment. We considered as seedlings all individuals of tree species less than 100 cm tall. We calculated richness, abundance, similarity, and the relationship of the frequency of seedlings to the height of the mulch. We sampled eight species with 42 seedlings, with only one not identified. The highest abundance and species richness were found in the treatment with mulch (n = 34 individuals; eight species), the most abundant being Schinus terebinthifolia Raddi (14 individuals) followed by Solanum mauritianum Scop. (11 individuals), and Platypodium elegans Vog. (three individuals). The presence of exotic grasses was lower in the plots of the mulching (13%) compared to the control treatment (67%). The highest frequency of seedlings was obtained with mulch height from 21 to 37 cm. We suggest that adaptive management practices, such as the use of the mulching technique, can be implemented in ecological restoration areas, because they favor the natural regeneration of native seedlings and can contribute to the control of exotic grasses, but the height of the layer must be controlled.

Soil Microbial Community and Enzymatic Activity of Grasslands under Different Use Practices: A Review

The usage of grassland significantly affects the microbial and biochemical parameters of soil epipedons. The use of grasslands (by mowing, grazing, and mowing and grazing) affects the dominance of bacteria in abundance relative to fungal populations. This was particularly noticeable when manual mowing was applied. In general, the highest number of microorganisms occurred during spring and summer, which should be associated with the intensity of growth of root systems of grass vegetation. It was noted that the grazing system caused an increase in the enzymatic activity of urease and slightly less dehydrogenases and acid and alkaline phosphatase. Therefore, microbial abundance and enzymatic activity are considered as indicator parameters to evaluate the biological soil environment. They are highly probable estimates of soil fertility and ecosystem biodiversity.

Intense mowing management suppresses invader, but shifts competitive resistance by a native to facilitation

Interactions among native and invasive species may affect management outcomes and goals. We implemented different mowing regimes to control the invasive Solidago gigantea and restore natural diversity, and also examined interactions between Solidago and a European native competitor, Tanacetum vulgare in the context of these regimes. Experimentally planted Tanacetum suppressed Solidago by 79% without management, and a suite of mowing management regimes reduced the density of Solidago by 80–98% when Tanacetum was absent. But, when Tanacetum was added, the density of the invader was not reduced by mowing. Put another way, in mowed plots with Tanacetum, Solidago was twofold to over fivefold denser than in mowed plots without Tanacetum. It is not clear why the effect of Tanacetum shifted from competition in the absence of disturbance to facilitation with intense management‐associated disturbance, but other studies suggest that Tanacetum may create plant–soil feedbacks that favor Solidago. Evidence shows similar shifts from competition to facilitation under mowing regimes for other species, but these are not mechanistically clear either. We speculate that mowing reduced competition from Tanacetum while leaving belowground facilitative effects unchanged, shifting the net effect of Tanacetum to facilitation. When single‐year mowed plots were abandoned for just 1 year, Solidago was twofold denser than in the control, thus maintaining treatments over time was important for successful management. Our results indicate that mechanical control may substantially alter biotic resistance gained from native competition.

Niche differentiation, competition or habitat filtering? Mechanisms explaining co‐occurrence of plant species on wet meadows of high conservation value

AbstractQuestionsDue to the diverse abiotic conditions and the extensive, early‐autumn, manual mowing practiced once per few years, Molinia semi‐natural wet meadows are known for their high plant species diversity. However, recent socio‐economic transformations and land‐use changes (i.e. cessation of use) have been contributing to significant biodiversity loss in Molinia meadows. Thus, understanding the mechanisms of species co‐occurrence patterns operating on well‐developed Molinia meadows may be a precondition for the restoration or regeneration success of this type of vegetation. We aimed to identify community‐level co‐existence patterns of the whole set of plant species typical of Molinia meadows, and to assess the role of co‐occurring vegetation in shaping the performance of individual species.LocationNatura 2000 Special Area of Conservation “Łąki Dąbrowskie” (S Poland).MethodsUsing generalised multiple regression techniques on a set of vegetation traits and components of functional diversity, we assessed the role of different ecological mechanisms in shaping co‐occurrence patterns of the entire group of species typical of Molinia meadows, as well as individual species belonging to this group.ResultsWhen the entire group of Molinia meadow species was taken into account, niche differentiation emerged as the main mechanism influencing the co‐occurrence of plant species. When considering individual species, we revealed that their co‐existence patterns were mostly species‐specific, pointing out the predominant role of either niche differentiation, competition, habitat filtering, or a combination of these three drivers in shaping assembly processes.ConclusionsOur results showed that the variability of niches realised by target species typical of Molinia meadows was high. Therefore, conservation of well‐developed Molinia meadows should focus on both the community, and on a single species level, aiming to maintain a complex of specific microhabitat conditions. Considering small‐size patches of these meadows scattered in a transformed, agricultural landscape, conservation of individual target species should be of the highest priority.

Understory mowing controls soil drying in a rainfed jujube agroforestry system in the Loess Plateau

The widely adopted practice of clean-cultivation in rainfed orchards in the Loess Plateau has led to serious soil erosion and degradation problems. Agroforestry is a promising management practice for solving these problems, but may reduce available soil water. Thus, reasonable soil and water management strategies should be developed for agroforestry systems in this region. The objective of this study was to determine whether adopting proper mowing management of the understory intercrop limited soil drying in a rainfed jujube (Ziziphus jujuba Mill.) orchard in this region. Various mowing intensities (3-, 6-, 9-cm stubble height and unmowed treatments) were imposed on three intercrop species: bluegrass (Poa pratensis L.), white clover (Trifolium repens L.), and hairy vetch (Vicia villosa Roth) to investigate and compare their root characteristics and soil moisture responses to mowing under greenhouse and field conditions. Based on the results, the most promising intercrop species and mowing intensity to be used in a jujube orchard were selected for field validation. The results showed that mowing effectively regulated intercrop root amount and distribution, as well as associated soil moisture conditions. However, the sensitivities of root characteristics and soil moisture to mowing and growth environment were species-specific. Bluegrass mowed to a 3-cm stubble height produced the minimum root amount, the shallowest root depth, and the greatest soil water content. When this treatment was applied to a rainfed jujube orchard during the 2015 and 2016 growing seasons, average soil moisture in the 0–300 cm soil layer was essentially unaffected, while fruit yield was increased. Consequently, bluegrass mowed to a stubble height of 3 cm when intercropped with jujube trees in the Loess plateau is a feasible practice to increase jujube yield and avoid extra soil drying.

Parasitism rate of Plebejus argyrognomon (Lepidoptera: Lycaenidae) under different levels of mowing management

AbstractPlebejus argyrognomon is an endangered grassland butterfly species in Japan. In this study we focused on the parasitism rate of tachinid flies under different mowing management to obtain knowledge of this possible top‐down effect that has been largely ignored. We established three mowing treatments differing in the intensity of mowing, as represented by vegetation height. The results showed that the parasitism rate of P. argyrognomon increased with vegetation height; the parasitism rate in blocks subjected to the highest mowing intensity was 8%, whereas in blocks subjected to the lowest mowing intensity, the rate was 42%. We suggest that clarifying interspecific interactions is important for understanding how habitat management affects grassland‐inhabiting butterflies in general.

REDUCTION NATURAL REGENERATION DENSITY OF Pinus elliottii BY MANUAL AND MECHANIZED MOWING

The methods of conducting the natural regeneration of Pinus elliottii are alternatives to planting with seedlings, where manual or mechanized mowing is carried out to reduce competition (density), while selective thinning is applied to select the most promising individuals. Thus, this study aimed to compare methods of conducting the natural regeneration of Pinus elliottii based on forest biometric variables: tree density ( ), basal area ( ), injuries to the remaining trees ( ) and production cost. For this, 19 circular plots of 380 m² were allocated in an experimental area of manual mowing with 22.5 ha and 6 plots in a mechanized mowing area with 7.2 ha. The Mann-Whitney test for independent samples was used to verify the existence of statistical difference between the discrete variables N and I , while the test t of Student de two samples, assuming different variances, were applied to the continuous variable G, both at the level of 5% significance. With of 2,012 trees/ha and of 4.07 m²/ha, mechanized mowing was more effective in controlling regeneration. No statistical difference was found between the methods referring to I, while the production cost of manual mowing was 51.7% higher. Thus, it is concluded that the method with mechanized mowing is the most suitable for conducting the natural regeneration of Pinus elliottii.

Intensive Mowing Effect of One Patch on the Metapopulations of Two Phengaris Species

Abstract In the second half of the 20th century, change of land use in the name of intensive agriculture was one of the most important factors caused significant loss of butterfly diversity in Europe. Phengaris nausithous and Phengaris teleius belong among the flagship species associated with wet meadows and are directly threatened by the intensive agriculture practises or management abandonment. Due to their very specific lifecycle, they are closely linked to their habitats and appropriate mowing management on their patches is thus crucial for their survival. Our research took place in Dolní Labe, Děčín, Czech Republic, on 16 patches and has been performed using Mark-Release-Recapture since 2009. This paper will illustrate how intensive mowing management, applied on only one of the patches, which forms only 9.4% of total locality size, can influence the entire local Phengaris metapopulation. The selected patch was intentionally mowed in the middle of flight season annually for four years. Even though, no significant effect was identified after the first year of study, after the second and third seasons, there was evidence of population decline of both studied species.