Effects Of Trampling Research Articles

Disentangling grazing effects: trampling, defoliation and urine deposition

AbstractQuestionsDo the effects of grazing components on vegetation structure differ in their relative importance? Do components interact in their effect on vegetation?LocationSan Jose department, Southern Campos, Uruguay.MethodsIn a manipulative field experiment we simulated three different grazing components: trampling, defoliation and urine deposition, over 3 yr in a natural grassland. Defoliation was analysed through two intensity levels and two procedures: uniform and selective cutting. We evaluated the effects of grazing components on species diversity and composition, and frequency of plant functional types.ResultsAll simulated grazing components had at least some effect on vegetation structure. Additionally, both individual and interactive effects on vegetation attributes were detected. Our study indicates that the relative influence of each grazing component varied according to the attribute considered. N addition was the only treatment that affected plant diversity. Plant functional type composition, in turn, was affected mainly by trampling. N addition and trampling were the component that affected the frequency of the largest number of species. Defoliation selectivity showed effects both in terms of plant functional type and species composition. Exclosure treatment and defoliation intensity had slight effects on grassland structure.ConclusionsThis study provides insight on the underlying mechanisms of some observed patterns of grazing on the Campos grasslands. Our results lead us to conclude that all grazing components have to be taken into account to understand vegetation dynamics subjected to grazing. Prevention of woody encroachment by grazing can be attributed to direct and indirect effects of trampling. Trampling should be taken into account to explain increaser species responses. However, mechanisms responsible for other general patterns remain less clear. The importance of selective defoliation in species replacement induced by grazing in these grasslands has yet to be clarified.

Simulated animal trampling of a free‐draining stony soil stimulated denitrifier growth and increased nitrous oxide emissions

AbstractWinter forage grazing systems in New Zealand cause compaction of soil by grazing animals, especially when the soil is wet. However, there is little information on the effects of animal trampling on denitrifiers in soil, despite their importance for N2O production. Here, we report a field study of the abundance of the denitrifying genes nirS, nirK, and nosZ and N2O emissions following the application of dairy cow urine in a free‐draining stony soil. Importantly, we found that simulated animal trampling altered some of the denitrifying microbial communities, thus leading to increased N2O emissions. Over the 111 day measurement period, the abundance of nitrite (NO2−)‐reducing nirS gene copy numbers increased significantly by 87% in the trampled soil with urine (P < 0.01) and increased by 40% in the trampled soil without urine (P < 0.05), but the nirS gene abundance did not change significantly in the nontrampled soil. The abundance of NO2− reducing nirK gene copy numbers was not affected by trampling, but increased significantly following urine application. The abundance of N2O‐reducing nosZ clade I and nosZ clade II gene copy numbers increased significantly in the trampled soil, but did not change significantly in the nontrampled soil. N2O emissions from the trampled soil were about twice that from the nontrampled soil without urine (1.20 and 0.62 kg N2O‐N per ha, respectively) and about eight times greater (6.24 kg N2O‐N per ha) than from nontrampled soil (0.80 kg N2O‐N per ha) when urine was applied. These results strongly suggest that animal trampling during winter forage grazing can have a major impact on denitrifying communities in soil, which in turn stimulate greater denitrification with increased N2O emissions.

Role of Herbivore Impact and Subsequent Timing and Extent of Recovery Periods in Rangelands

The productivity and stability of cattle production on rangelands depends on the maintenance of a dense and productive perennial grass−dominated resource base, which is contingent on appropriate grazing and recovery periods. We investigated the effect of simulated trampling, dung inputs, frequency of defoliation in the previous growing season (grazing history), and timing of recovery periods on various grassland functional responses in two experiments in western and northwestern Botswana. A field-based clipping experiment at the individual tuft scale demonstrated that perennial grasses are most productive when rested for a full growing season, but that productivity of the highly palatable soft leaved Brachiaria nigropedata Ficalho & Hiern. decreases exponentially with increasing clipping frequency in the previous season (a lagged effect of grazing history). This species was also more productive in the next season when rested during the early than late growing season. The less palatable needle-leaved Stipagrostis uniplumis Licht. ex Roem. & Schult. was less resistant to defoliation than B. nigropedata and decreased equally at each clipping frequency regardless of season. A second field-based experiment at the plot scale demonstrated that a full-season recovery period increased tuft densities while its combination with dung increased cover. The effects of hoof trampling on sandy nutrient-poor grasslands appear to be less significant compared with grasslands on fertile soils. Thus, optimal livestock management strategies should aim to promote season-long grazing of both palatable and unpalatable species to disadvantage the less grazing-tolerant unpalatable species and full growing season recovery periods to ensure optimal recovery and future productivity.

Combined impacts of natural and human disturbances on rocky shore communities

Most ecosystems are subject to both natural and human disturbances that can combine to influence populations and assemblages in complex ways. Assessing the relative influences and combined impacts of natural and human disturbance is crucial for managing human uses of ecosystems against the backdrop of their natural variability. We evaluated the separate and combined influences of disturbance from storm waves and disturbance associated with human trampling of rocky shores by conducting an experiment mimicking controlled levels of trampling at sites with different wave exposures, and before and after a major storm event in central California, USA. Results show that trampling and storm waves affected the same taxa and have comparable and additive effects on rocky shore assemblages. Both disturbance types caused significant reduction in percent cover of mussels and erect macroalgae, and resulted in significant re-organization of assemblages associated with these habitat-forming taxa. A single extreme storm event caused similar percent cover losses of mussels and erect macroalgae as did 6–12 months of trampling. Contrary to a predicted synergistic effect of trampling and storm damage, we found that impacts from each disturbance combined additively. Mussel beds in wave-exposed sites are more vulnerable to trampling impacts than algal beds at protected sites. Mussels and erect macroalgae recovered within five years after trampling stopped. These results suggest that impacts from local human use can be reversed in relatively short time frames, and that cumulative impacts can be reduced by setting recreational carrying capacities more conservatively when ecosystems are already exposed to frequent and/or intense natural disturbances.

Goat trampling affects plant establishment, runoff and sediment yields over crusted dunes

AbstractMainly attributed to goat and sheep trampling, the sand dunes at the Israeli and the Egyptian sides of the border present contrasting geomorphological conditions. In an attempt to assess the trampling effect upon vegetation, runoff and sediment yield, two pairs of plots and miniplots (each pair contains a trampled plot and a control) were constructed during 1991 and monitored during 1991–1995. In order to assess the impact on vegetation, three pairs of vegetation plots, subjected to light, medium and heavy trampling, were established during 1993 and monitored. In addition, the effect of the micro structures created by the goat hooves (mounds and depressions) were studied in three pairs of plots subjected to medium trampling during 1993 and monitored during 1993–1996. As far as trampling intensity is concerned, the findings indicate an increase in species diversity, density and biomass from the intact crusted surface to the plots subjected to light and medium trampling with a decrease thereafter at the plots subjected to heavy trampling. As for the micro scale, the findings indicate significantly higher plant biomass for the first 2 years at the hooves‐formed mini mounds and mini depressions in comparison to intact crusted surfaces, with no significant difference during the third year. Significantly lower runoff and sediment yields characterized the trampled plots implying a reduction in water redistribution. The data point to the differential effect that trampling has upon plants and soil. While increasing annual plant growth along the slope, it hinders runoff flow to the footslope, negatively affecting water availability for footslope vegetation. Recovery, as also supported by chlorophyll and microrelief measurements, was scale dependent (attributed to differential supply of aeolian sand) with estimated recovery for the plots and miniplots being 4–5 and 8–10 years, respectively. The data indicate that upon the cessation of grazing and under similar precipitation regime, recovery time of the biocrust in the Sinai sand dunes may be short, within 5–6 years. Copyright © 2016 John Wiley & Sons, Ltd.

Human impacts on biogenic habitats: Effects of experimental trampling on Sabellaria alveolata (Linnaeus, 1767) reefs

Human trampling is one of the main anthropogenic threats to coastal communities, especially in rocky intertidal habitats. The adverse effects of human trampling have recently received increasing attention from conservation biologists, especially when concerning species playing key functional roles. These include biogenic reefs providing extremely productive and diverse habitats due to their structural heterogeneity and three-dimensional complexity. The degradation of such habitats could not only adversely affect the whole coastal biota, but it could also have strong socio-economic implications. This study investigated the potential impact of human trampling on biogenic reefs built by the honeycomb worm Sabellaria alveolata in north-western Portugal. Three increasing intensities of human trampling were manipulated to test for their direct effects on S. alveolata bio-constructions and indirect effects on associated benthic infauna. Experimental trampling, even at low intensity, negatively affected reefs by reducing the percentage cover of intact S. alveolata concretions over a period of two months, but it did not alter the structure of whole assemblages compared to the unmanipulated condition. Idiosyncratic responses were shown by the most conspicuous taxa, ranging from no significant effects on S. alveolata and Amphipoda to spatially and temporally variable effects on the Syllidae and Sabellidae polychaetes, the Mytilidae bivalves and the Rissoidae gastropods. When present, however, differences were always in the direction of larger abundances under the highest intensity of trampling than in the less disturbed treatments and the unmanipulated control. This study provides one of the first experimental evidence linking the intensity of human trampling to the physical damage of S. alveolata reefs. Direct implications of present findings as tools to promote a sustainable use of these systems at a local scale and to stimulate protection and management initiatives at other locations are discussed.

五大连池药泉山大型土壤动物对旅游踩踏的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 五大连池药泉山大型土壤动物对旅游踩踏的响应 DOI: 10.5846/stxb201603230518 作者: 作者单位: 哈尔滨师范大学;黑龙江大学,哈尔滨师范大学,黑龙江大学,北京林业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41101048） Responses of soil macrofaunal communities to tourism trample in the Wudalianchi Yaoquan Mountains Author: Affiliation: Harbin Normal University;Heilongjiang University,Harbin Normal University,Heilongjiang University,Beijing Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以黑龙江省五大连池世界地质公园的药泉山为研究对象，按照距离游道的远近分为重度踩踏区，轻度踩踏区和非踩踏区3种踩踏干扰强度，分析大型土壤动物数量，群落组成，多样性对旅游踩踏干扰的响应。研究结果表明不同干扰区之间大型土壤动物类群数量差异显著（P<0.001），重度踩踏区显著低于轻度踩踏区和非踩踏区。不同干扰区大型土壤动物个体数差异明显（P<0.001），其中轻度踩踏区个体密度最大（68头/m2），重度踩踏区个体密度最小（10头/m2）。不同踩踏强度干扰区H’指数差异明显（P<0.05），轻度踩踏区及非踩踏区的多样性显著高于严重踩踏区。典型对应分析表明旅游踩踏主要通过改变土壤理化特性而影响大型土壤动物的组成及其多样性，重度踩踏区、轻度踩踏区和非踩踏区对大型土壤动物影响最显著的因子分别为土壤全氮含量，土壤含水率和土壤全磷含量。 Abstract:Trampling is widespread among various recreational activities, and this can become a significant problem as it represents a major disturbance affecting the vegetation and soil surface horizon. Soil macrofauna, mainly in the soil surface horizon, are good indicators for studying the impact of human activities. In the present study, Yaoquan Mountain of Wudalianchi World Geo-park was considered as a study example in 2012. The areas surrounding tourism trails were divided into no-trampling, mid-trampling, and high-trampling plots, which were divided based on three different interference types. The effect of human trampling on soil macrofaunal communities at a depth of 0-10 cm were studied along an increasing distance from the tourism trail of Yaoquan Mountain. A completely randomized design, including three replicates from three trampling interference sites, was used. Soil macrofauna were separated by hand, and were identified and counted. Soil bulk density, soil moisture content, soil organic matter content, total nitrogen content, and total phosphorus content were measured from each site. Our study evaluated the structure, composition, diversity, and distribution of soil macrofauna in three different tourism trample types, and assessed the impacts of human activity. The results were summarized as the following aspects:The total number of soil animal genera was significantly different in the three disturbance degree sites (P<0.001) and the least number of genera occurred in high trampling sites. The individual density of soil macrofauna was significantly different from the other kinds of soil animal fauna in the three disturbance degree sites (P<0.001), the maximum value was in the mid-trampling plots (68 ind./m2), and the minimum value was in the high-trampling sites (10 ind./m2). The Shannon index (H') of soil micro-fauna were seriously affected by trampling (P<0.05), and the high trampling sites had the lowest H' index. A canonical correspondence analysis indicated the soil macrofaunal distribution in the mid-trampling and high-trampling plots differed from the no-trampling plots. The main factor affecting soil macrofauna distribution was soil total nitrogen content, soil moisture content, and total phosphorus content in no-trampling, mid-trampling, and high-trampling plots, respectively. 参考文献 相似文献 引证文献

Effect of cattle trampling on ground nesting birds on pastures: an experiment with artificial nests

Abstract 1. In semi-natural grasslands, nest trampling by cattle can have a strong effect on hatching success but the relationship linking cattle density, incubation time and nest survival has for now only been hypothesized. 2. Based on an experiment with artificial nests, the objective of this study was to test the theoretical model generally used to estimate nest survival. In spring 2009, we conducted a one-month experiment on permanent grasslands of the French western marshlands grazed at three different stocking rates (1 LU.ha-1, 2 LU.ha-1 and 4 LU.ha-1). 3. The results confirmed that trampling depended on stocking rates. 4. Trampling had a major effect on nest survival (32-85% of nests destroyed). 5. The theoretical model classically used by managers and modellers proved to be a good approximation of the dynamics of nest trampling. 6. Synthesis and applications: We conclude that nest trampling has a major impact on nest survival in pastures and that the use of such a model could help managers to define acceptable levels of cattle densities.

Efeito de diferentes sistemas de pastejo em atributos físicos do solo

In view of the importance of the interaction soil-climate-plant-animal to attain good yields in the system, the objective of this study is to evaluate changes in soil physical properties caused by grazing systems continuous and rotated. The systems were used: conventional (CC): Brachiaria brizantha cv. BRS Piatã, unfertilized annual replacement, managed under continuous stocking; fertilizer (AD): Brachiaria brizantha cv. BRS Piatã managed under rotational stocking system, with annual replacement fertilization with NPK at a ratio of 45-20-20 kg ha-1 year-1, and intercropping (IC): Consortium of Brachiaria brizantha cv. BRS Piatã and Stylosanthes Campo Grande, managed in a rotational system of stocking, fertilization receiving annual replacement with 00-20-20 NPK kg ha-1 year-1. To evaluate the effect of animal trampling on systems with rings were collected soil samples with undisturbed layers from 0.00 - 0.06 m, 0.06 - 0.12 m before and after grazing for the determination of soil density by the volumetric ring method, macroporosity and total porosity by the method of the tension table, were also collected samples deformed structure in the same layer for determining the organic matter content. The resistance to penetration was determined before and after grazing in the depths of 0.0 - 0.1, 0.1 - 0.2, 0.2 - 0.3 and 0.3 - 0.4 m, with the impact penetrometer. Animal stepping changed only the microporosity, the use of different cropping systems and grazing no differences in relation to organic matter content. The soils of the conventional grazing system were more tendency to soil compaction measured by penetration resistance of roots.

Ecological response to human trampling and conservation status of Helianthemum caput-felis (Cistaceae) at the eastern periphery of its range

Border and isolated plant populations represent an interesting target for ecological and conservation issues. We analysed the ecological constraints and the conservation status of the eastern population of Helianthemum caput-felis Boiss. (Cistaceae), located in Sardinia. The distribution of H. caput-felis was verified via field surveys; ecological data, morphological and reproductive traits, were recorded in 40 permanent plots randomly established; the human trampling effects on plant density, plant size and plant performance were analysed. Plant density was higher in bedrock and lowland areas, in garrigue and maquis habitats; however, the differences among plants growing in different ecological conditions were not statistically significant; only human trampling intensity significantly affected plant density and lowest values were observed in areas with intense trampling pressure. All ecological variables analysed had a statistically significant effect on plant size and on the number of fruits per plant. In particular, larger plants were found in areas with the following ecological features: presence of structured soil, on the slopes, in the maquis habitat, and in areas with intensive human trampling. Conversely, plants displayed a higher fruits output per plant in deep and structured soil, in lowland areas, and in the garrigue and maquis habitats; the mean fruits output per plant increased as human trampling intensified. Human-induced threats are the main hazards threatening the remaining Sardinian population. In particular, the major threats are linked to tourism and other outdoor activities (i.e. human trampling), followed by the expansion of agricultural activities; all of these threats result in the disappearance of small localities and in reduced population size due to habitat loss and fragmentation. Our study indicates that H. caput-felis should be considered as Critically Endangered (CR) at the regional level. Urgent measures should be undertaken to protect the remaining H. caput-felis population in Sardinia and a possible integrated strategy for the conservation and management consists of a combination of in situ and ex situ measures. In particular, greater emphasis should be given to minimizing the negative impacts of unsustainable tourism and recreation use, in order to exclude human trampling and to facilitate the plant recruitment process and population renewal. In addition, an ex situ conservation strategy must be implemented and the seeds collected could be used for future translocations in suitable areas. Moreover, considering the threats observed, a long-term monitoring programme must be developed to reveal changes in the species conservation status.

Susceptibility of soil to wind erosion in arid area of the Central Rift Valley of Ethiopia

In Central Rift Valley (CRV) of Ethiopia, renewable land resources are under pressure. Acacia woodland clearance, frequent cultivation, crop residue removal and mono-cropping are among the major land mis-management practices in the area. This has largely been affecting the soil quality. The current study is aimed at assessing the impact of Acacia woodland conversion, and the subsequent mis-managements on selected soil physical properties, and their relation to the prevailing wind erosion in the area. For this study, four land use/land cover types, namely protected woodland (PWL), managed pastureland (MPL), parkland agroforestry (PAF) and treeless cropland (TLCL) were considered. Higher (P 0.25 mm) fraction of soil was found under PWL and MPL while higher fraction of micro-aggregates (0.053–0.25 mm) of soil was found under PAF and TLCL. Soil under PAF and TLCL had higher (P < 0.001) proportion of aggregates of < 1 mm, implying potential susceptibility of the soil to wind erosion. Higher soil bulk density (BD) was found in the most top layer (0–15 cm) of TLCL and PAF, and this could be attributed to the trampling effect by animals freely released to these land use types. In the study area, conversion of native woodland to PAF and TLCL and the subsequent mismanagements negatively affected some soil physical properties, thereby enhancing severity of soil erosion by wind. In contrast, although not commonly practiced by smallholder farmers, soil under MPL is more stable and less susceptible to wind erosion.

Effects of human trampling on abundance and diversity of vascular plants, bryophytes and lichens in alpine heath vegetation, Northern Sweden.

This study investigated the effects of human trampling on cover, diversity and species richness in an alpine heath ecosystem in northern Sweden. We tested the hypothesis that proximity to trails decreases plant cover, diversity and species richness of the canopy and the understory. We found a significant decrease in plant cover with proximity to the trail for the understory, but not for the canopy level, and significant decreases in the abundance of deciduous shrubs in the canopy layer and lichens in the understory. Proximity also had a significant negative impact on species richness of lichens. However, there were no significant changes in species richness, diversity or evenness of distribution in the canopy or understory with proximity to the trail. While not significant, liverworts, acrocarpous and pleurocarpous bryophytes tended to have contrasting abundance patterns with differing proximity to the trail, indicating that trampling may cause shifts in dominance hierarchies of different groups of bryophytes. Due to the decrease in understory cover, the abundance of litter, rock and soil increased with proximity to the trail. These results demonstrate that low-frequency human trampling in alpine heaths over long periods can have major negative impacts on lichen abundance and species richness. To our knowledge, this is the first study to demonstrate that trampling can decrease species richness of lichens. It emphasises the importance of including species-level data on non-vascular plants when conducting studies in alpine or tundra ecosystems, since they often make up the majority of species and play a significant role in ecosystem functioning and response in many of these extreme environments.

The effect of animal trampling and DCD on ammonia oxidisers, nitrification, and nitrate leaching under simulated winter forage grazing conditions

Dairy winter forage grazing on free-draining soils is a common practice within the Canterbury region of New Zealand. The high stocking rates involved and the associated deposition of urine onto wet soils during winter create a high risk of nitrate (NO3 −) leaching from soil. The objective of this study was to determine the effect of animal trampling and the use of a nitrification inhibitor, dicyandiamide (DCD), on soil ammonia oxidisers, nitrification, and nitrate leaching under simulated winter forage grazing conditions. A lysimeter trial was carried out using a Balmoral stony silt loam under a kale forage crop. Nitrate leaching losses, the effect of soil trampling, and the effect of DCD were measured. Soil nitrification rates and ammonia-oxidising community abundance and activity were measured in companion soil blocks under simulated dairy winter forage grazing conditions. Animal trampling was found to reduce peak nitrate-N (NO3 --N) concentrations in drainage water from urine patch areas by 43 %. In addition, animal trampling reduced the total amount of NO3 −-N leached from urine patches by 34 %. However, animal trampling did not affect the growth or activity of the ammonia oxidisers. The use of DCD was found to be highly effective in reducing the concentration and amount of NO3 −-N leached from urine patches. Dicyandiamide applications reduced peak NO3 −-N concentrations in drainage water by 66 %, and the total amount of NO3 −-N leached was reduced by 61 % under the simulated dairy winter forage grazing conditions. Ammonia oxidising bacteria (AOB) were more abundant than ammonia-oxidising archaea (AOA) and were responsible for mediating the nitrification process. These results suggest that both animal trampling and the use of DCD separately reduces soil nitrification rates and thus NO3 − leaching.

Experimental evidence that even minor livestock trampling has severe effects on land snail communities in forest remnants

Summary Land‐use intensification is increasing dramatically in production systems world‐wide. Livestock production is an important component of production land use, and increases in livestock densities have had a wide range of negative consequences. The off‐site effects of livestock grazing and trampling on native vegetation adjacent to pastoral land have received less attention than on‐farm effects. Moreover, where significant ecological effects of livestock spillover have been identified, the mechanistic determinants of these effects have not typically been investigated. Here, we tested the mechanistic drivers of livestock trampling effects on land snail communities in forest remnants using simulated trampling under field conditions. We used a factorial combination of leaf‐litter manipulation and trampling treatments to partition different causal drivers of livestock impacts on land snail communities and related them to five environmental variables that are altered by livestock. We show that even very low frequency trampling caused severe changes to land snail communities. Land snail density, even under the lowest trampling frequency, declined by an average of 42 individuals m−2 and land snail species richness decreased by an average of 10 species per plot compared with control plots. The underlying drivers of changes in land snail communities varied, but were primarily linked to leaf‐litter mass, rather than soil compaction. Synthesis and applications. Overall, these results suggest that even minimal disturbance by livestock has large effects on land snail communities, but the underlying drivers of these effects require further investigation in longer duration and more intensive studies. Our results provide strong support for livestock exclusion as an important management tool for native forest remnants embedded within production landscapes.

Response of intertidal sandy-beach macrofauna to human trampling: An urban vs. natural beach system approach

Sandy beaches are subjected to intense stressors, which are mainly derived from the increasing pattern of beach urbanization. These ecosystems are also a magnet for tourists, who prefer these locations as leisure and holiday destinations, and such activity further increases the factors that have an adverse effect on beaches. In the study reported here the effect of human trampling on macrofauna assemblages that inhabit intertidal areas of sandy beaches was assessed using a BACI design. For this purpose, three contrasting sectors of the same beach were investigated: an urban area with a high level of visitors, a protected sector with a low density of users, and a transitional area with a high level of human occupancy. The physical variables were constant over time in each sector, whereas differences were found in the intensity of human use between sectors. Density variations and changes in the taxonomic structure of the macrofauna with time were shown by PERMANOVA analysis in the urban and transitional locations whereas the protected sector remained constant throughout the study period. The amphipod Bathyporeia pelagica appears sensitive to human trampling pressure and the use of this species as a bioindicator for these types of impact is recommended.

Tree ring analysis as an indicator of environmental changes caused by tourist trampling — A potential method for the assessment of the impact of tourists

This paper shows that tree-ring trends might be used for the assessment of the intensity of trampling along touristic tracks in the forests. The study aims at determining the effects of trampling, on the dynamics of annual increments in trees subject to pressure from hiking tourism. The studies were conducted at a spruce stand in the Tatra Mts., on sections of different trails. Within each trail, four transects were determined. Transects include the zones with damage from trampling and the un-affected areas, treated as a reference zones. Selected trees growing in both zones were sampled by coring and the core samples were used to develop sequences of annual increment widths. Next, the dynamics of increments in trees growing in the tourist zone and the reference zone were compared. The decrease in the annual increments was significantly more rapid in trees growing directly along the trail that those in trees deep in the forest stand in one locality. This finding may testify the adverse effects of hiking along tourist routes on the radial increments in trees in the neighbourhood of the trails. The results of the study indicate that the impact of trampling in the form of soil compaction and mechanical damage to root systems of trees may, to some extent, be compensated by better light access and lessened competition experienced by trees growing along the edges of hiking trails. Tree-ring analyses might be an efficient alternative for assessment of tourism intensity conducted by the other methods.

Reality and confusion in the recognition of post-depositional alterations and use-wear: an experimental approach on basalt tools

While many experimental studies have been done on siliceous and metamorphic rocks for both use-wear and post depositional surface modification (PDSM) events, little is known about such experiments on volcanic materials (other than obsidian), and on basalt in particular. Here we present the preliminary results of several experiments related to: a) evidence for basalt use (e.g., butchery and fresh hide scraping) and the subsequent characteristic use-wear patterns that can be seen; and b) post-depositional surface modifications caused by bear ( Ursidae ) trampling on experimental basalt flakes and subsequent use of these flakes for a tumbling experiment in a special tumbling machine. The results of these experiments were compared to better understand some surface modifications noted on the Middle to Upper Pleistocene lithic assemblages of the Azokh Cave site (Nagorno Karabagh, Lesser Caucasus). Although some aspects of both events (use-wear and PDSM) remain to be studied in depth, the experiments have improved our understanding of the effects of use-wear and post-depositional trampling and tumbling on basalt lithic artefacts. In particular, it has allowed us to recognise mechanical alterations (e.g., cracks, striations, fractures, edge damage) caused by trampling and tumbling and to note differences between these modifications and those caused by use. In particular, the experiments have shown that macroscopic modifications are rarely diagnostic, especially those observed after use. Microscopic wear features such as edge rounding, polish, abrasion and striations were the most evident types of alteration on basalt flakes, although occurring at different times and from different types of use. Distribution and orientation of alterations may be key in distinguishing use-wear from post-depositional alterations on basalt artefacts.

Fragmentation and recreational use affect tree regeneration in urban forests

The aim of this study was to test whether fragmentation or recreational use affect tree regeneration in urban forests, and to quantify these effects. We sampled tree saplings at different distances from edges in spruce (Picea abies) dominated forests, and at different distances from paths that represented different levels of wear. Generalized linear mixed models were used to test our hypotheses. We found that fragmentation favours the regeneration of deciduous trees in urban spruce dominated forests: distance from the edge had a pronounced effect on regeneration, at least up to 80m into the forests. Saplings of Betula pendula, Populus tremula, other deciduous species and Pinus sylvestris benefited from edge conditions. Betula pubescens saplings, however, were most abundant in the interior and small Sorbus aucuparia saplings at 25–30m from the edge. All species suffered from the direct effects of trampling, while varying responses of species to distance from the paths were observed up to 6m, and possibly further. As trees essentially define the living conditions for other forest species, we suggest that the spatial extent of edge and trampling effects should be studied for different types of forests. This knowledge should then be used in urban forestry and planning to define the threshold value that will allow for at least some “intact” interior. We suggest a diameter larger than 160m to support indigenous species in boreal spruce dominated forests.

Chemical and physical soil attributes in integrated crop-livestock system under no-tillage

Although integrated crop-livestock system (ICLS) under no-tillage (NT) is an attractive practice for intensify agricultural production, little regional information is available on the effects of animal grazing and trampling, particularly dairy heifers, on the soil chemical and physical attributes. The objective of this study was to evaluate the effects of animal grazing on the chemical and physical attributes of the soil after 21 months of ICLS under NT in a succession of annual winter pastures (2008), soybeans (2008/2009), annual winter pastures (2009), and maize (2009/10). The experiment was performed in the municipality of Castro (PR) in a dystrophic Humic Rhodic Hapludox with a clay texture. The treatments included a combination of two pasture (annual ryegrass monoculture and multicropping - annual ryegrass, black oat, white clover and red clover) with animal grazing during the fall-winter period with two animal weight categories (light and heavy), in a completely randomized block experimental design with 12 replications. After the maize harvest (21 months after beginning), soil samples were collected at 0-10 and 10-20 cm layers to measure soil chemical and physical attributes. The different combinations of pasture and animal weight did not alter the total organic carbon and nitrogen in the soil, but they influence the attributes of soil acidity and exchangeable cations. The monoculture pasture of ryegrass showed greater soil acidification process compared to the multicropping pasture. When using heavier animals, the multicropping pasture showed lesser increase in soil bulk density and greater macroporosity.

Human trampling effects on Mediterranean coastal dune plants

Coastal habitats are particularly vulnerable to recreational impacts because these environments are highly dynamic and continually change in response to biotic and abiotic factors. Sand dune communities are worldwide characterized by high levels of biodiversity, but are often affected by human-induced impacts as those caused by tourist trampling. To understand the effects of human frequentation, trampling, and other human-induced impacts, fencing experiments have been traditionally carried out on coastal dunes. Since in touristic areas dune systems are subjected to different intensities of human frequentations rather than to opening or fencing, in this study we explore the effects of accessibility on vascular plants cover. This study tests the hypothesis that human frequentation on beaches affects spatio-temporal variability of vascular plant abundance on dunes by comparing the plant assemblages of high and low accessible sites in North-East Sardinia (Italy). Our results show that accessibility plays a crucial role in conditioning the percentage of vegetation cover in Mediterranean dunes. In fact, not only we found a perennial vegetation cover that was significantly higher in the sites with low accessibility (and consequently low frequentation), but we also showed that at the sites with high accessibility there were significant differences in vegetation cover between times of sampling (cover was higher before than after summer): on the contrary, differences in perennial vegetation cover among times were not significant at the low frequentation sites. After summer, the difference among low and high frequentation sites in species composition and cover was >90%. Multivariate analysis identified those species that play a pivotal role in differentiating the low and the high frequentation sites. Among them, Crucianella maritima and Sporobolus virginicus can be considered as differential species. Overall, our data show vegetation and plant species responses to human-induced impacts, and are therefore important to support conservation actions in Mediterranean coastal areas interested by mass tourism.