Elemental and stable isotope composition of Pinus halepensis foliage along a metal(loid) polluted gradient: implications for phytomanagement of mine tailings in semiarid areas

Background and aims

Aleppo pine (Pinus halepensis Mill.) is a widely used species for restoring degraded semiarid areas, but its use for the revegetation of metal(loid) polluted soils has not been thoroughly investigated. The main goal of this research was to study the ecophysiological status and elemental composition of spontaneous populations of Pinus halepensis growing on mine tailings to assess their use in phytomanagement of mine spoils in semiarid climates.

Methods

Edaphic characteristics and the physiological (by stable isotopes) and nutritional status of pine trees were determined on mine tailings, in the metalloid-polluted surroundings and a non-polluted control area.

Results

Low soil phosphorus availability at the tailings was found to be a more important limiting factor for pine physiological performance than high soil metal(lloid)s concentrations. Foliar phosphorus concentrations showed a strong negative correlation with foliar sulphur concentrations along the studied transect. The carbon and oxygen isotopic composition (δ¹³C and δ¹⁸O) of pine needles indicated that trees at the tailings were less water stressed than those in surroundings or control areas. The low foliar δ¹⁵N of pines growing at the tailings was due to low soil fertility and/or a heavy reliance on symbiotic ectomycorrhizal fungi for nitrogen uptake.

Conclusions

The results of this study indicate that Pinus halepensis is a suitable tree species for the phytostablisation of neutral or slightly-alkaline mining wastes in semiarid environments, thanks to its drought hardiness and good adaptation to low soil fertility and salinity.     

Monitoring of coral reefs with linear transects: A study of storm damage

Monitoring of coral reefs in the U.S. Virgin Islands through repeated sampling of linear transects revealed that Hurricane David (August 1979) caused significant changes in the amounts of live and dead hard coral cover on these reefs, i.e., cover by scleractinians and the hydrozoan Millepora. Mean percent cover of the most abundant coral species, spatial indices (a measure of bottom topographical complexity), the number of species within transects, the diversity index (H'), and the evenness (J'), did not, however, change significantly as a result of this storm. Mortality in corals did not appear to be species specific. Monitoring of established transects proved to be an effective way of quantifying storm damage. With the increasing interest in management of coral reefs, this technique could also be useful for assessing other types of reef destruction.     

Distribution pattern of the invasive alien plant Bunias orientalis in Rów Podtatrzański trench,north of the Tatra Mts,Poland

Bunias orientalis is an alien species that has spread greatly in recent decades in Central Europe. This coloniser is particularly well (pre)adapted to anthropogenic disturbances and human-mediated dispersal, allowing it to spread mainly along roads and railways. Here, its distribution and population structure is investigated for the sub-montane region located in the northern foothills of the Tatra Mts. Based on 70 phytosociological samples of invading vegetation, the relationships between B. orientalis cover and species diversity, together with the composition of vegetation, were analysed using regression analysis. Comparison of the current distribution of B. orientalis within the investigated area with published records indicates that the expansion rate of this alien species is not particularly high, despite its increased frequency in anthropogenic habitats and meadows. Meadows invaded by this species revealed that increased B. orientalis cover was accompanied by a significant reduction in the values of the Inverse Simpson diversity index and Pielou’s measure of evenness. Reduced diversity was caused by considerable decrease in cover by species of the Molinio-Arrhenatheretea class. However, for anthropogenic habitats, no statistically significant relationships were found to occur between the abundance of B. orientalis, species diversity and vegetation composition.     

不同植物群落下铜尾矿废弃地生物结皮中真菌群落结构的比较

分布于铜尾矿废弃地的裸地表面及维管植物群落中的生物土壤结皮在尾矿废弃地生态恢复过程中扮演重要角色。利用分子生物学技术探讨了不同维管植物下以及不同演替阶段的生物土壤结皮中真菌的多样性及其群落结构的变化。结果表明:生物土壤结皮中的真菌主要包括子囊菌门(Ascomycota)、担子菌门(Basidiomycota)和壶菌门(Chytridiomycota),其中子囊菌门占绝对优势,其相对丰度为55.12%—87.73%,其次为担子菌门相对丰度为12.27%—43.86%;不同样本真菌群落结构在门、纲、目以及属的水平存在显著差异;生物土壤结皮中真菌群落结构和多样性的差异与维管植物群落类型以及演替阶段不同的生物土壤结皮的类型有关,与基质化学性质之间无显著的相关性。     

Assessment of heavy metals accumulation by spontaneous vegetation: Screening for new accumulator plant species grown in Kettara mine-Marrakech,Southern Morocco

The present paper aims to perform a screening of native plants growing in Kettara mine-Marrakech (Southern Morocco) for its phytoremediation. Plants and soil samples were collected and analyzed for Pb, Zn, Cu and Cd concentrations at several sites in the mine. The results showed that the soil in the vicinity of Kettara mine is deficient in major elements and contain toxic levels of metals. Spontaneously growing native plants were botanically identified and then classified into 21 species and 14 families. Significant difference was observed among the average concentrations of four heavy metals (Pb, Zn, Cu and Cd) in plants (p ≤ 0.05). Six plants of 21 species namely Hammada scoparia (Pomel) Iljin, Hirschfeldia incana (L.) Lagreze-Fossat, Lamarckia aurea (L.) Moench, Calendula algeriensis Boiss. & Reuter, Aizoon hispanicum L. and Melilotus sulcata Desf. were considered as the best-performing specimens due to their high ability to accumulate multiple metals in their shoots and roots without sustaining toxicity. This was confirmed by the transfer factors generally higher than 1. Using the most common criteria to classify the hyperaccumulator plants, these species can be classified as new accumulator plants of many heavy metals and be potentially used as remediation tools of metal-contaminated sites.     

北京松山自然保护区森林群落物种多样性及其神经网络预测

物种多样性是群落结构和功能复杂性的一种度量,物种多样性的空间分布格局受许多环境因子的影响.运用多样性指数,多层感知器网络,分析了松山保护区森林群落物种多样性与群落类型、结构和生境之间的关系.结果表明:(1)大果榆+山杨混交林、油松+青杨混交林物种丰富度、多样性和均匀度均较高,而大果榆林、华北落叶松林的各项指数值均较低.Patrick指数和Shannon-Weiner指数在森林群落中均表现为草本层＞灌木层＞乔木层;Pielou指数在榆林中表现为草本层＞乔木层＞灌木层,而在其他森林群落中表现为灌木层＞草本层＞乔木层.(2)功能层物种多样性在海拔梯度上的变化趋势不同,在乔木层,丰富度、多样性和均匀度随海拔的升高逐渐降低;在灌木层,丰富度、多样性和均匀度均呈比较明显的单峰曲线变化趋势;在草本层,丰富度和多样性随海拔的升高都呈下降趋势,而在草本层,均匀度变化不大.(3)用多层感知器网络预测功能层多样性效果很好,结果发现坡向对乔木层和灌木层物种多样性的影响最大,而海拔高度对草本层物种多样性的影响最大.     

Natural Revegetation of a Boreal Gold Mine Tailings Pond

Understanding the natural revegetation of forests disturbed by the dumping of mine wastes is vital for the success of reclamation strategies. The Gunnar gold mine tailings pond in southeast Manitoba has remained largely unvegetated since the mine was closed in 1942, with limited vegetation developed on one side of the pond. We examined the natural Picea mariana/Larix laricina forest that has developed on the pond to determine how the plant community develops and what changes in the tailings are associated with this development. Vegetation sampled along transects showed a consistent pattern of succession from Equisetum palustre to Salix spp., and Populus balsamifera, to Larix laricina and finally to P. mariana. Larix laricina and P. mariana are moving into the site at the rate of 1.5 m per year with L. laricina invading 4 years ahead of P. mariana. Both tree species show a similar pattern of annual growth, showing positive correlations with spring precipitation, a pattern also occurring on L. laricina growing on a nearby site. The establishment of E. palustre was accompanied by initially rapid decreases in compaction and conductivity of the tailings, and an increase in inorganic nitrogen. Surface organic matter depth, coarse organic matter mass, and soil organic carbon increased at a constant rate, whereas subsurface coarse organic matter had an initial rapid increase followed by a gradual increase. As fern allies (and specifically members of the Equisetaceae family) have a number of properties that facilitate succession on mine wastes, their use should be explored further.     

Zooplankton Diversity of Osmansagar Reservoir,Telangana, India

Zooplankton composition and diversity in Osmansagar reservoir, Telangana, India were investigated during the year 2010–2012. Collected data revealed the occurrence of 66 species of zooplankton, of which 50 rotifers, 14 cladocerans and two copepods. The population density of zooplankton varied from 83 to 1080 Ind./L. The highest density was due to rotifer and copepod population. Diversity (H′) was ranged from 0.679 to 2.631, evenness (J′) was 0.257 to 0.904 and species richness was 8–24. The less diversity and evenness was observed in November 2011, March and August 2012, because of copepoda dominance by Mesocyclops leuckarti. The population abundance of zooplankton was Brachionus forficula, Brachionus diversicornis, Brachionus calyciflorus, Keratella tropica, Trichocerca similis and Diaphanosoma sp. especially during the summer seasons in both the years. There was no seasonal periodicity of any zooplankton communities, but the population turnover was observed from rotifers to copepoda over the study period. The significant inter and intra relationship between and within physicochemical and zooplankton indices were noted. It is found that surface water temperature, magnesium and total hardness could be a limiting factor for the species richness. Dominance may be due to the numerical abundance of rotifer and copepod and it has a positive significant correlation with pH.     

缙云山针阔混交林更新层物种多样性林隙梯度变化初探

根据对缙云山针阔混交林群落更新层的样带调查数据,采用Margalef物种丰富度指数（R）、Simpson多样性指数（D）、Shannon-Wiener指数（H）、Pielou均匀度指数（J）及Alatolo均匀度指数（E）来研究更新层物种多样性的林隙梯度变化。结果表明：从非林隙到林隙中心,更新层物种多样性逐渐升高,即非林隙＜林隙边缘＜林隙近中心＜林隙中心;物种丰富度变化与其一致,而均匀度变化则表现为两端高中间低的现象;更新层物种多样性林隙梯度变化程度受林隙发育阶段的影响较大,随着林隙的发育,变化程度为早期林隙＞中期林隙＞晚期林隙。     

豚草入侵对新疆伊犁河谷林下本地草本植物群落结构的影响

为探究外来入侵植物豚草（Ambrosia artemisiifolia）对本地植物群落结构的影响,结合区内林下草本植物调查和室内分析方法,分析了豚草不同入侵压力下（无入侵、轻度入侵、中度入侵、重度入侵）本地草本植物丰富度、盖度等特征,探讨了地形、气候、土壤、光照、人口密度等外部因素与豚草种群特征、本地植物群落结构之间的关系。结果表明：豚草种群盖度与其高度、密度、生物量显著正相关。与对照相比,轻度入侵下本土草本植物Shannon-Wiener多样性指数和Pielou均匀度指数显著增加,丰富度、盖度未出现显著差异。随着豚草入侵程度加剧,本地草本植物物种丰富度、盖度极显著降低,样方Shannon-Wiener多样性指数先升高再降低,本土草本植物Pielou均匀度指数差异不显著。冗余分析（RDA）表明,土壤全氮、与道路距离、土壤全磷、郁闭度对研究区植物群落结构影响最大,土壤全氮含量随豚草盖度和生物量增加而减少,距道路越近或光照越强,豚草盖度和生物量越高。增强伊犁河谷地区交通往来货物豚草检验检疫力度、增加林内植被郁闭度或是抑制区内豚草入侵的有效手段。     

基于冗余分析的城市森林林下层植物多样性预测

以4类多样性指数作为衡量城市森林林下层植物多样性差异的定量指标,并同时记录对应样方尺度的环境变量特征.以期应用冗余分析(RDA)手段提取城市森林林下层植物多样性的干扰控制因子,从而进一步揭示主要环境变量对城市森林林下层植物多样性变异的贡献率.RDA分析结果表明枯落物盖度、距林缘距离、小路面积和垃圾数4变量为能够显著解释林下叶层植物多样性变化的最小变量组合,解释信息量百分比达61%,10变量共同解释的信息量为72.1%.在RDA分析的基础上,对10环境变量组合与植物多样性特征进行双重筛选逐步回归,发现草本密度与海拔、坡度、距林缘距离、枯落物盖度呈极显著相关;草本层Pielou均匀度指数与海拔、坡度、郁闭度、枯落物盖度、岩石盖度呈极显著相关;草本层Simpson多样性指数与坡度、枯落物盖度、距林缘距离、岩石盖度、伐桩数呈极显著相关;灌木层Pielou均匀度指数则与海拔、郁闭度、小路面积、岩石盖度呈极显著相关.     

晋、陕、宁、蒙柠条锦鸡儿群落物种多样性对放牧干扰和气象因子的响应

根据晋、陕、宁、蒙地区13个样地的野外调查资料,采用丰富度指数、物种多样性指数以及均匀度指数,研究了柠条锦鸡儿群落物种多样性对放牧干扰和气象因子的响应。结果表明：（1）晋、陕、宁、蒙地区柠条锦鸡儿群落组成成分简单,共记录种子植物111种,分属25科,64属,灌木层优势种为柠条锦鸡儿,草本层优势种集中于禾本科、豆科、菊科蒿属和藜科;（2）受人为干扰、土壤和气候等影响,群落的组成、结构及其综合性质具有一定差异性,主要表现在群落的Patrick指数与Simpson指数、Shannon-wiener指数出现较大的波动,且波动趋势基本一致,Pielou指数表现较为稳定;（3）放牧干扰强度与群落Simpson指数、Shannon-wiener指数呈极显著相关（P＜0.01）,与Patrick指数、Pielou指数呈显著相关（P＜0.05）,群落丰富度随放牧干扰强度的增大而下降,群落多样性和均匀度指数在D2和D3时呈现峰值,表明适度干扰可以提高群落物种多样性和均匀度;（4）Patrick指数、Simpson指数和Shannon-wiener指数均与年均降水量呈极显著正相关(P＜0.01),与相对湿度呈显著正相关（P＜0.05）,共同体现了水分条件是制约柠条锦鸡儿群落物种多样性的决定性因子。     

Diversity and habitat association of medium and large mammals in Gibe Sheleko National Park,Southern Ethiopia

Complete documentation on the status of mammals is indispensable for appropriate conservation measures in protected areas. However, there is inadequate information on mammalian resources in the ecosystem of Gibe Sheleko National Park (GSNP). Thus, the study aimed to assess species diversity, abundance, and habitat association of medium‐ and large‐sized mammals in GSNP. We stratified the study area into five dominant habitat types, namely dense forest, wooded grassland, grassland, riverine forest, and farmland habitat types based on land cover and vegetation structures and further employed stratified random sampling technique across each habitat type. The sample transects covered 20% of the study area. Transect width ranged from 50 m to 400 m based on vegetation cover and visibility of mammals. The main data were collected via direct observation. Data were analyzed via chi‐square test and species diversity indexes. We recorded the total of 20 mammals species'' those belong to 10 families of which 8 species were large‐sized and 12 species medium‐sized mammals. There were two IUCN vulnerable species, namely Hippopotamus amphibious and Panthera pardus, and two globally near‐threatened species, particularly Litocranius walleri and Caracal caracal in the study area. Dense forest held the highest species diversity of medium‐ and large‐sized mammals (H′ = 2.28) with the highest evenness index (J = 0.84). Riverine forest had the least diversity with uneven population distribution. Papio anubis was the most abundance species, whereas Caracal caracal was the least abundant in the study area. GSNP is home for threatened and spectacular mammals species''; hence, an appropriate conservation measure is mandatory to keep existing mammals species''.     

Analysis of the structure of bacteria communities and detection of resistance genes of quinolones from pharmaceutical wastewater

The aim of the present study was to investigate the distribution of bacteria and detect the presence of quinolone resistance gene (qnrA) and integrons (intI1, intI2) in a habitat polluted by pharmaceutical sewage. The bacteria were isolated by nutrient agar and nutrient broth from waste water and sludge collected from the sewage outfall of a pharmaceutical factory. The bacteria were identified by Gram staining and biochemical tests, and the bacterial community diversity was analyzed by Shannon–Wiener diversity index (H), Pielou evenness index (J) and Simpson’s diversity index (D). The occurrence of qnrA and integrons (intI1, intI2) were detected by Real-time PCR assays. The results showed that 90 strains were isolated from water samples and sludge samples including 22 genera and 26 species. Types of bacteria in water samples contained 18 genera and 20 species, while 13 genera and 14 species were detected in sludge samples. Fifty-five Enterobacteriaceae isolates (61.11 %, 55 of 90) were the predominant bacteria in water and sludge samples. Bacterial species richness and evenness in water samples were higher than in sludge samples. The resistance genes of qnrA and integrons (intI1, intI2) with the total DNA and single isolate plasmid DNA were detected. There were a variety of bacterial species and the presence of qnrA and integrons (intI1, intI2) genes in pharmaceutical wastewater habitats, in which Enterobacteriaceae strains were the dominant bacteria. These results suggested that pharmaceutical wastewater had potential risks to public health.     

Restoration of vegetation around mining enterprises

This paper is devoted to the restoration of vegetation around mining areas on the example of two land-reclamation zones in the Borodinsky coal mine during spring-summer of 2011–2021. Analysis of vegetation in this area has shown that indicators of spontaneous plant diversity in plots No. 1 and No. 2 were considered moderate in both layers (H < 2.5). Underwood and seeding diversity indices at pre-mining sites were ranked high, reaching 4.01–4.25 and 3.78–3.82, respectively. The analysis of the biological diversity of the flora in the undergrowth of the 12-year-old plot revealed approximately 29 spontaneous plant species belonging to 25 genera and 18 families. The most significant number of species found was found from the family Euphorbia, Cereals, and Legumes. At the 18-year-old site, the number and diversity of plant species (38 species) belonging to 38 genera and 27 families are slightly larger, with the most significant number of species within Euphorbiaceae and Poaceae, Asteraceae, Rubiaceae and Leguminosae. Saplings of various tree species from the Euphorbia and Leguminous family, such as Euphorbia cyparissias L., E. fischeriana Steud., Desmodium triflorum L., Indigofera gerardiana (Wall.) Baker, Robinia viscosa Vent. grew well in both plots. Many other spontaneous species of trees were also found in small populations at the 18-year-old site, namely, Pinus sylvestris L., Salix alba L., Populus alba L., and P. tremula L. In contrast to the younger site, some seedlings of small trees like S. alba and P. tremula and terrestrial ferns such as common bracken (Pteridium aquilinum (L.) Kuhn) and adiantum capillus-veneris L. prevailed in the older site.     

Effect of vegetation cover on the abundance and diversity of ladybirds (Coccinellidae) assemblages in a peat bog

Predaceous ladybirds are important natural enemies of many insect pests in terrestrial ecosystems such as peatlands, which are habitats for specialized cold-adapted plants. Ladybird assemblages of pristine peat bogs have not yet been assessed. In total, 15 ladybird species were recorded in peat bog in Belarus by using entomological sweep net. The present study shows low diversity, evenness and species richness of ladybird assemblages. However, a small number of species were present in high numbers. These are Coccinella hieroglyphica, Chilocorus bipustulatus, Coccinulla qutuordecimpustulata and Hippodamia tredecimpunctata. Ladybird abundance was positively related to shrub cover and number of vascular plant species, and negatively related to herb cover. In terms of ladybird diversity, only shrub cover had a significant negative effect.     

Aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) in cultivated and non-cultivated areas of Markazi Province, Iran

The fauna of aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae), as well as their diversity and tritrophic (parasitoid-host aphid-host plant) associations in cultivated and non-cultivated areas of Markazi province, was studied during 2004–2009. Thirty species of Aphidiinae belonging to 9 genera were identified. There are presented, in total, 73 associations with 32 host aphids occurring on 42 host plants. Five parasitoid-aphid associations are newly recorded from Iran. Lysiphlebus cardui (Marshall) is newly recorded for the fauna of Iran. Lysiphlebus fabarum (Marshall) and Diaeretiella rapae (M’Intosh) were the most abundant species in non-cultivated (72.96%) and cultivated (41.17%) areas, respectively. In the non-cultivated areas, L. fabarum was found on eight aphid species, while in cultivated areas it was only found on Aphis craccivora Koch. In cultivated areas, Sitobion avenae (F.) has the greatest diversity of parasitoids (Shanon-Weiner H = 0.875) whereas in non-cultivated areas the greatest diversity of parasitoids was recorded upon Acyrthosiphon pisum (Harris) (Shanon-Weiner H = 1.149). Significant differences were found between diversity of two ecosystems based on the overall diversity indices. Both species diversity and evenness were greater in cultivated ecosystems. The results are discussed in relation to the over-all parasitoid-aphid-plant associations in the area.     

铜陵铜尾矿废弃地生物土壤结皮中的蓝藻多样性

生物土壤结皮是生态系统原生演替过程中的一个早期阶段,在铜陵铜尾矿废弃地自然生态恢复过程中生物土壤结皮在尾矿废弃地表面广泛分布.以生长在铜陵杨山冲和铜官山2处铜尾矿废弃地的生物土壤结皮为研究对象,运用常规培养方法和变性梯度凝胶电泳技术(PCR-DGGE)对不同群落生物土壤结皮中的蓝藻多样性及优势类群进行研究.结果表明2种研究方法所获得的蓝藻种类组成具有明显差异.显微观察结果表明常规培养试验中主要蓝藻类群为微囊藻属(Microcystis)、色球藻属(Chroococcus)、颤藻属(Oscillatoria)、念珠藻属(Nostoc)和浮鞘丝藻属(Planktolyngbya),其中优势种类主要为铜绿微囊藻(Microcystis aeruginosa)、断裂颤藻(Oscillatoria fracta)和细浮鞘丝藻(Planktolyngbya subtilis);提取样品中微生物总DNA,对蓝藻16SrRNA进行PCR-DGGE分析,回收DGGE图谱中24个条带进行测序分析,结果显示,所有序列与GenBank数据库中的近缘蓝藻的相似性系数均在93％以上,其中优势蓝藻类群主要隶属于微鞘藻属(Microcoleus)和细鞘丝藻属(Leptolyngbya),裸地(YL)处和木贼群落下尾矿表面(YM)的生物土壤结皮中优势蓝藻类群主要为微鞘藻属,而黄色真藓-藻类混合结皮(YT)和白茅群落( YB,TG)下的生物土壤结皮中的优势类群主要隶属于细鞘丝藻属.     

Genetic diversity of Lotus corniculatus in relation to habitat type,species composition and species diversity

The genetic variability of Lotus corniculatus, a common and important fodder legume, was studied in relation to habitat type and to species diversity at a local level. The study was conducted in Cholomontas mountain, northern Greece, at altitudes of 760–870 m. Genetic material was selected from four forested, at the edge of forest, and four open grassland sites, and was studied with the aid of ISSR molecular markers. The plant cover at each study site was measured and the floristic composition was estimated. The percentage of graminoides increased in grassland sites with high grazing intensity, while the abundance of legumes, including L. corniculatus, forbs and woody species, increased in forested sites with low grazing intensity. Gene diversity H_E within the studied populations of L. corniculatus ranged from 0.167 to 0.213 and Shannon index (I) from 0.269 to 0.340. Genetic differentiation was detected between habitats as well as among the populations in each habitat, although it was low, 3% and 7% respectively. However, genetic differentiation was significant within the populations (90%). Genetic diversity of L. corniculatus was not correlated with species diversity (richness and evenness) either within or between populations, while was negatively correlated with L. corniculatus abundance.     

Above-ground arthropod community structure and influence of structural-retention management in southern Patagonian scrublands,Argentina

Southern Patagonia’s landscape hosts several semi-natural habitats, traditionally used for sheep production, such as Mulguraea tridens and Lepidophyllum cupressiforme scrublands. Mulguraea scrublands are managed via mechanical shredding to remove shrubs and increase grass availability, alternating with structural-retention strips. We analyzed the influence of structural-retention management (with cut and retention strips) in Mulguraea scrublands with regards to above-ground arthropod community structure, as well as differences between the two natural scrubland types. We worked in Santa Cruz Province (Argentina) with pitfall traps during two summers in the first 2 years after mechanical shredding. Richness, abundance, occurrence frequency, Shannon–Wiener diversity and Pielou evenness indices, and similarity among assemblages were evaluated using univariate and multivariate statistical tests. Complementarily, we described vegetation ground cover and microclimate. We collected 3279 individuals from 38 species belonging to Insecta and Arachnida Classes. Shannon–Wiener diversity and Pielou evenness indices, as well as the overall assemblages, differed significantly between managed cut strips and natural Mulguraea scrublands, mainly due to the loss and introduction of species from surrounding environments; abundance also differed in the first sampling year compared to the second year. Likewise, managed retention strips allowed the partial maintenance of arthropod community structure and had a microclimate that was similar to natural Mulguraea scrublands, although assemblages in managed cut and retention strips became more similar among themselves in the second sampling year. On the other hand, richness, abundance and assemblage of both natural scrubland types differed significantly, with 87?% more indicator species in Mulguraea than in Lepidophyllum scrublands. Greater dissimilarity occurred between both natural scrubland types in dryer years, which could be related with an El Niño Southern Oscillation event. If arthropod community structure changes prove stable over time, mechanical shredding with structural-retention management would allow for an increase in the sheep carrying capacity, while reducing impacts to the arthropod community, thus providing a viable compromise between productivity and conservation in a fragile arid environment. More studies are necessary to evaluate long term changes in above-ground arthropod community structure of scrublands in arid zones of southern Patagonia.