Litter Thickness Research Articles

Effects of the types and ages of vegetation restoration on land surface roughness in the Eastern Hobq Desert, Northern China

Vegetation restoration has an important remodelling effect on near-surface characteristics, and consequent changes in land surface roughness (LSR) are key influences on soil wind erosion processes. However, the effects of vegetation restoration types and ages on LSR and the underlying mechanisms are not fully understood. In this study, the sand-fixing vegetation restoration area of the Hobq Desert was examined in comparison to a bare sand control area. The LSR of four artificial vegetation types (Salix psammophila, Caragana korshinskii, Artemisia ordosica, and Populus simonii) with restoration age of 36 years, and Salix psammophila and Caragana korshinskii after different periods of restoration (20, 28, 36 and 45 years) were measured using Structure-from-Motion (SfM) photogrammetry. Near-surface characteristics that may affect LSR were also measured. The results showed that vegetation restoration was associated with a 230–409 % higher LSR compared to the control site (1.74 mm). LSR in the different vegetation restoration areas were ranked, from high to low, as follows: AO (8.85 mm) > CK (7.89 mm) > SP (6.70 mm) > PS (6.61 mm). LSR also increased with time since restoration, with the greatest rate of increase during the first 20 years. The change of LSR is mainly affected by the change of near-surface characteristics, with the direct effects of biological crust thickness (0.331), litter thickness (0.289), soil bulk density (−0.239), and clay content (0.171) being significant. Stem diameter, litter density, biological crust coverage, and soil organic matter affected LSR indirectly, mainly through acting on the above factors. Finally, LSR was effectively estimated based on biological crust thickness, litter thickness, and soil bulk density (R2 = 0.904). The research results will help to further deepen the understanding of the influence mechanism of vegetation restoration on LSR, and provide scientific basis and practical reference for vegetation ecological restoration in similar areas.

Decoupling the effects of near-surface characteristic change on soil roughness in a dune-meadow cascade ecosystem

As an important indicator of ecological restoration, soil roughness changes exhibit a synergistic evolutionary relationship with near-surface characteristics such as soil and vegetation. However, the main controlling factors for changes in soil roughness in different ecosystems are still unclear. This study was conducted to clarify the changes in soil roughness in different ecosystems and to decouple and quantify the impact of near-surface characteristics on soil roughness in the Horqin Sandy Land (China). Soil roughness was measured using the structure-from-motion (SfM) technique, showing a pattern of farmland (14.08 mm) > semi-mobile dune (12.59 mm) > meadow (6.19 mm) > woodland (5.67 mm). Redundancy analysis (RDA) results showed that the near-surface characteristics of the dune-meadow cascade ecosystem that explained soil roughness, in descending order of importance, were as follows: sand, soil moisture content (MC), silt, plant stem diameter (SD), clay, pH, soil organic matter (SOM), soil shear resistance (SC), litter thickness (LT), water-stable aggregates (WSA), litter density (LD) and bulk density (BD). Specifically, in the semi-mobile dune ecosystem, the order of total effects on soil roughness was as follows: sand (1.311) > pH (0.447) > clay (0.387). In the woodland ecosystem, SC (0.226), pH (|-0.216|), and LD (0.179) were important factors controlling soil roughness. In the farmland ecosystem, MC (0.380), LT (|-0.378|), and SOM (|-0.336|) were the main controlling factors of soil roughness. In the meadow ecosystem, silt (0.574), SOM (|-0.413|), and clay (|-0.380|) significantly influenced soil roughness. Compared to other machine learning models and stepwise regression models, the k-nearest neighbors (KNN) model could predict soil roughness changes more accurately. The findings of this research are of great significance for ecological restoration and sustainable development of the ecologically fragile areas in northern China.

Influence of herbaceous litter thickness on bacterial community structure and physicochemical properties of aeolian sand.

The change and mechanism of soil and soil bacterial diversity during the change of herbaceous litter thickness in desert areas is crucial to understand. In the study, the dominant herbaceous litter mixture in Baijitan National Nature Reserve was selected as the research material, and an experiment was established by adjusting the litter depth. The results showed that the measured values of soil physicochemical factors (total nitrogen, total protein, total potassium, available phosphorus, available potassium, pH, and soil water content) increased with the increase of herbaceous litter mixture thickness in 0-5cm soil layer. Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, and Gemmatimonadetes were the dominant bacterial phyla under different thicknesses of herbaceous litter in 0-5 and 5-10cm soil layers. Balneimonas, Rubrobacter, and Geodermatophilus were the dominant bacterial genera under different thicknesses of herbaceous litter in 0-5 and 5-10cm soil layers. There was no obvious change in the α-diversity index of bacterial community the same soil layer, but the α-diversity index in the 0-5cm soil layer was lower compared to the 5-10cm soil layer. The results of this study revealed that the change of herbaceous litter thickness had no significant effect on soil bacterial community structure in desert areas.

Microtopographic effect on soil temperature during a burn by shifting cultivation in a tropical rain forest

Fire is an important component of shifting cultivation systems. Although its effects on soil properties depend on its severity and duration, few studies have measured soil temperature during burns at different depths and in relation to topography in tropical forests. Frequent rain keeps the soil moist in these ecosystems, but soil moisture does not only depend on precipitation but also on relief position. Here we monitor soil temperature at 1 and 10 cm depth before the burn along elevation gradients of three logged hillsides to establish the daily temperature variation, and to compare it with the soil temperature under forested sites and during the burn. Additionally, moisture content and physicochemical properties of the soil were measured before and after the burn.Results before the burn indicate a larger daily temperature amplitude in logged versus forested areas, and specially at crests and shoulder positions in comparison to backslopes and toeslopes. The fire increased soil temperature only in 1 cm depth, and for less than 40 degrees at most of the sites. Soil moisture content was negatively correlated with maximum temperature during the burn, however, also fuel loads and litter thickness determined fire intensity, with the spatial distribution of these variables being unrelated to topography. Nutrient contents changed only in the litter layer, in which C and N diminished by 35 % and 24 %, respectively, while total Ca, Mg, K and P increased by 210, 202, 318, 235 % respectively. We conclude that soil moisture contents contributed to maintain fire intensity low at the studied site.

Environmental role of different‐aged pine and oak stands growing on post‐agricultural and forest lands in forming the Mesostigmata mites communities

AbstractReclamation of agricultural soil and forest succession after afforestation proceeds slowly and at many levels. Therefore, the history of land use is recorded in the soil's physical, chemical and ecological parameters for many decades. This process depends on time and the form of afforestation, which primarily includes tree species. In our study, we analyzed differences in the physical and chemical characteristics of pine and oak stands on forest and post‐agricultural land at 22, 42 and 62 y/o. Our study revealed that 14 of 24 examined parameters (litter pH, soil pH, litter thickness, soil organic matter, Corg, bulk density, C/N ratio, soil moisture, soil K, Mg and Mn content, N and Ca litter content, Mg litter content) differed significantly among examined habitats (land use, stand age and tree species). We calculated the abundance, species richness and diversity of the mite communities (Acari, Mesostigmata) for each habitat type. In total, 6730 mites were classified into 72 taxa (60 species, 11 genera and one taxon as family). The highest abundance was recorded in 42 y/o. oak stands on post‐agricultural land, while the lowest is in 22 y/o. pine and oak stands on post‐agricultural land. The highest species richness and diversity were recorded in the oldest oak stand on post‐agricultural land. In contrast, the lowest diversity was recorded in the youngest oak and pine stands on post‐agricultural land. Our results demonstrate that the negative impact of the agricultural history of land use weakens over time and provides a better understanding of land use history on the relations between the soil environment and soil fauna, including mesostigmatid mite assemblages.

Sustainable forest development in the face of global warming: Optimizing Robinia pseudoacacia L. stands to alleviate soil moisture depletion

To foster sustainable forest development amid global warming, it is imperative to enhance the quality of existing forest stands while avoiding excessive depletion of soil moisture. This study established 24 Robinia pseudoacacia L. standard plots (40 × 40 m2) in the Caijiachuan watershed, located in the gully region of the Loess Plateau, Shanxi Province, China, to monitor soil moisture content from 2007 to 2021. Additionally, the study examined the influence of 19 ecological factors, including climate, topography, and stand characteristics, on soil moisture. The findings indicated a sustained decline in soil moisture storage across the 0–200 cm soil profile, with significant depletion at 0–140 cm. The soil moisture content at depths of 80–200 cm was critically low, resulting in a “dry soil layer” during years with low precipitation. Climatic factors (average annual temperature and annual precipitation) and stand factors (uniform angle index, stand density, litter thickness, and Simpson diversity index of the shrubs) emerged as dominant factors impacting soil moisture variations. An increase in average annual temperature due to global warming, compounded by suboptimal stand density, primarily drove soil moisture depletion. Using a multivariate optimization equation to model the relationship between dominant factors and soil moisture storage, this study recommends a dynamic stand management strategy. This strategy involves selective thinning or replanting of Robinia pseudoacacia L. trees, targeting a gradual reduction in optimal stand density from 1500 to 1000 plants·ha−1 over the next two decades. Additionally, transitioning stand spatial arrangements from uniform or clustered to random distributions, maintaining ideal litter thickness (2.43–2.47 cm), and enhancing shrub diversity are advisable. Such measures can alleviate soil moisture deficits in Robinia pseudoacacia L. stands attributable to global warming, thereby promoting the Loess Plateau's sustainable forestry advancement.

Response of spontaneous plant communities to microhabitats in a riparian corridor in Beijing, China

With the increasing urban environmental problems, spontaneous vegetation has been gradually emphasized for high ecological value, whose distribution has been reported as strongly influenced by fine-scale environmental factors. As one of the major zones for urban spontaneous vegetation distribution, urban riparian corridors are well suited for research on the response of spontaneous plants to microhabitats. Taking the Wenyu River-North Canal in Beijing as the study site, we measured six microhabitat factors, including the level of maintenance and visitor activity, canopy density, litter thickness, and distance to water and road, to investigate their effects on spontaneous plant assemblages. The results showed that spontaneous plants respond significantly to fine-scale habitat variation, and were more responsive to human disturbance than other factors. Compared with diversity indicators, the functional trait compositions were more significantly correlated with microhabitat factors. Under lower maintenance of plants, the spontaneous communities had a higher invasion risk for plants. Thick litter can impede the occurrence of invasive species while favoring the growth of native ones. Our findings are important for furthering understanding of the spontaneous plant community establishment, and can serve as a good reference for the maintenance and management of spontaneous plants in urban riparian corridors.

Study on the Influence of Canopy Density on Cycling of Soil Available N in Different Landform of Loess Plateau in China

In this paper, a total of 330 soil samples with 0-100cm soil depth of 66 planted square forest (10*10m) with different canopy density in the Loess Plateau were selected for the determination and analysis of soil N content in different soil layers, and the effects of different canopy density on soil N cycle under different topographic factors of planted forest were studied. The results showed as follows: (1) the migration mechanism of different N forms to the root surface was different, the migration of nitrate nitrogen to the root surface mainly depended on mass flow, there was enrichment phenomenon near the root, ammonium nitrogen mainly through diffusion, resulting in deficiency and loss in the near rhizosphere, and the leaching loss of nitrate nitrogen was affected by soil water and root growth. (2) The thickness, composition and decomposition rate of litter were different due to different canopy density, which affected the content of ammonium nitrogen and nitrate nitrogen in forest soil. (3) Although the change of different regions in this region was spatially different, keeping the stand cover in the middle and high range of 0.75-0.8 can be conducive to maintaining the balance between the consumption of soil nutrients by the stand and the supplement of nutrient consumption, which can also be conducive to the sustainable recovery and growth of the stand in this region.

Influencing factors on regeneration and seedling survival prediction in Larix principis‐rupprechtii plantations in northern China

AbstractThe natural regeneration of forest ecosystems is crucial for their sustainability, but uncertainties have impeded the regeneration of some tree species. Identifying influencing factors and effective strategies to enhance seedling survival and growth is essential. We investigated factors affecting the natural regeneration of Larix principis‐rupprechtii and provided insights into seedling survival and growth. Eighteen artificial L. principis‐rupprechtii forest plots were established and monitored for 3 years. A logistic regression analysis and generalized linear models were used to investigate the influence of stand age, diameter at ground level, height, and other microhabitat factors on seedling regeneration. The microhabitat factors significantly influenced the overall L. principis‐rupprechtii regeneration density, as well as the density and growth of regenerated trees in different height classes. The area under the curve values for total nitrogen (0.796), total phosphorus (0.726), soil moisture (0.759), and litter thickness (0.633) were the highest, indicating a significant impact on the survival rate and mortality of the seedlings. Among these values, total nitrogen sensitivity (0.857) and specificity (0.810) were the highest, and the optimal threshold was 0.940. The survival rate decreased with increasing forest age, and the stands aged 4–7 years with a height of 1–2.5 m and a diameter at the ground level of approximately 2 cm constituted a relatively vulnerable and critical set of conditions for the survival of L. principis‐rupprechtii seedlings. The model showed that at 12 years old, L. principis‐rupprechtii trees were no longer vulnerable to mortality. The Kaplan–Meier model predicted future seedling survival through the construction of the comprehensive influence value and the measured seedling survival number. The model can be used to evaluate the survival rate for the final regeneration of a species, and targeted artificial seeding or replanting can improve the proportion of seedlings that survive. Our findings contribute to elucidating the factors affecting the natural regeneration of forest species and provide valuable insights for the development of effective regeneration strategies.

Effects of litter thickness on natural regeneration of Larix principis-rupprechtii plantations

In this study, we explored the thickness influence of undecomposed litter layer and semi-decomposed litter layer on the natural regeneration in an artificial pure forest of Larix principis-rupprechtii in the forest area of Guandi Mountain. We divided the litter into an undecomposed layer and a semi-decomposed layer, which was further divided into eight groups based on the thickness. The results showed that when the thickness of undecomposed layer was 0.32-0.83 cm, and that of semi-decomposed layer was 0.18-0.89 cm, the regeneration index was larger (≥0.15), and the regeneration was better. When the thickness of undecomposed layer was more than 1.1 cm and that of semi-decomposed layer was more than 0.5 cm, the regeneration index was smaller (≤0.07), and the rege-neration of understory was worse. Results of redundancy analysis showed that the undecomposed layer thickness of litter had a high and stable explanatory ability for natural regeneration, with a contribution rate of 38.7%, while the semi-decomposed layer thickness had no significant effect on natural regeneration. Structural equation modeling revealed that the thickness of undecomposed layer of litter increased the mechanical resistance to seed germination which had a negative direct effect on natural regeneration (-0.617), and a positive indirect effect on natural rege-neration by influencing the content of alkali-hydrolyzed nitrogen and available phosphorus (+0.178). The combined effects (-0.439) showed an inhibitory effect on the natural regeneration. In conclusion, the thickness of undecomposed layer of litter under L. principis-rupprechtii was most closely related to natural regeneration, and the thickness of semi-decomposed layer had a minimal effect on natural regeneration.

Diversity of Collembola on Various Post-Rehabilitation Land Covers

The success of rehabilitation has altered environmental conditions from critical land to new habitats for living organisms. One of the representative and sensitive mesofauna to environmental changes is Collembola. Various vegetation cover almost all of the rehabilitation area, which has impacts on microclimate and soil quality as important factors to Collembola existence. This study investigated the diversity and abundance of Collembola and its relation to environmental factors on various land covers, including teak, grass, and mixed stand land cover. Data were collected in an observation plot of 20 m × 20 m using purposive samples, including environmental measurements, Collembola collection, and soil samples for physical and chemical analysis. The results showed that different land covers affected the abundance and diversity of Collembola, even though the statistical analyses of TLC, GLC, and MLC were not significantly different. However, TLC has a higher litter thickness and organic material than the other land cover types. A few families of Collembola, such as Cyphoderidae, Brachystomellidae, Katiannidae, Isotomidae, Oncopoduridae, and Isotogastruridae, show their correlation to climatic and edaphic factors in a certain land cover.

Differential Water Conservation Capacity in Broadleaved and Mixed Forest Restoration in Latosol Soil-Eroded Region, Hainan Province, China.

The water conservation capacity of the litter and soil layers of forest ecosystems improves the function of forest ecosystems in conserving soil and water. Plantation restoration plays a key role in preventing soil erosion. In order to evaluate the water conservation capacity of plantation restoration in Latosol soil-eroded region, we analyzed the litter thickness and mass, water absorption process, water holding recovery process, and soil water holding capacity of five restoration types (Hevea brasiliensis, Acacia mangium, Eucalyptus robusta, Acacia-Eucalyptus, and Acacia-Hevea) in the Mahuangling Watershed, Hainan province. The results showed that the thickness of the litter ranged from approximately 3.42 ± 0.24 to 4.73 ± 0.81 cm, and the litter mass ranged from 5.04 ± 1.52 t·ha-1 to 13.16 ± 1.76 t·ha-1, with higher litter mass in the SL layer than in the UL layer. The litter mass of A. mangium was higher than that of H. brasiliensis, E. robusta, Acacia-Eucalyptus, and Acacia-Hevea, which was 3.16 ± 1.76 t·ha-1. A. mangium forest was significantly higher than other plantation restoration types in terms of the maximum water retention capacity (Qmax) and the effective water retention capacity (Qeff). The soil bulk weight ranged from approximately 1.52 ± 0.09 to 1.59 ± 0.08 g·cm-3, and porosity ranged from 31.77 ± 4.72 to 35.62 ± 3.02%, both of which increased with the depth of the soil layer. The water holding capacity of 0-60 cm soil varied from approximately 12.94 ± 7.91 to 45.02 ± 31.79 t·ha-1, with A. mangium having the best soil permeability and the strongest soil water holding capacity. The entropy weight method was used to conduct a comprehensive evaluation, and the results showed that the water conservation capacity of the soil layer was 1.26 times higher than that of the litter layer, in which the water conservation capacity of A. mangium was the strongest, with a comprehensive evaluation value of 0.2854, which effectively intercepted rainfall and reduced surface runoff. Hence, we suggest that the planting of A. mangium should be considered in future ecological restoration projects of the erosion area of Mahuangling in order to improve the function of conserving soil and water in a restoration forest ecosystem.

Soil health reduction following the conversion of primary vegetation covers in a semi-arid environment

A degraded forest is the outcome of a degradation process that has adverse effects on ecosystem functions and services. This phenomenon results in alterations of soil physicochemical and biological properties, which serve as valuable indicators for assessing soil health that has been recognized as a crucial component of soil quality. For several decades, the conversion of forested areas into rangeland has been documented in specific regions of the world. There is a widespread lack of global understanding regarding the lasting consequences of land degradation on soil health indicators. The present study aims to investigate the impact of forest degradation on soil health indicators in a mountainous semi-arid region located in northern Iran. The study area was predominantly forested, but due to human activities over the past 30 years, it has been transformed into three distinct land uses: forest, forest-rangeland ecotones and rangeland. In each of these land covers, a total of 20 litter (O-horizon) and 20 soil (from two depths of 0–15 and 15–30 cm) samples were collected in the summer (August 2022) season. According to our results, the highest litter thickness, P and Mg were in forest ecosystem, the lowest in rangeland ecosystem. The findings indicated that following the conversion of forest to rangeland, there was a decrease in soil aggregate stability, porosity, soil organic matter, POC, PON, NH4+, NO3− and nutrient levels, while soil bulk density increased. The forest ecosystem showed notably higher C and N stocks (45 and 5.21 Mg ha−1) in comparison to the rangeland (38 and 3.32 Mg ha−1) ecosystem. In addition, P, K, Ca, and Mg exhibited elevated levels within the total root of the forest ecosystem (2.12, 1.23, 0.71, and 0.38 %, respectively), whereas the lower values (1.29, 1.01, 0.43, and 0.23 %, respectively) were found in the rangeland ecosystem. Following the shift of land cover from forest to rangeland, soil fauna, microflora populations, soil enzymes and microbial activities decreased (about 1–2 times higher in the forestland). This research emphasizes the urgent need to advance sustainable management practices to prevent further degradation and promote the implementation of restoration or rehabilitation techniques in degraded forests. Despite being conducted in a semi-arid region situated in northern Iran, the findings of this study have considerable value for the sustainable management of soil and land conservation in various other semi-arid regions around the world.

Dynamics of Species Richness in Understory Deciduous Teak Forest (Tectona grandis)

Teak plantation forest is a deciduous forest that sheds its leaves during the dry season. It is generally a secondary forest that is managed in a monoculture manner so that it is homogeneous. However, when teak sheds its leaves, it that may impacts the dynamics of understory species changes due to differences in environmental factors growing in the dry and wet seasons. The study observed 90 plots carried out over a year, namely two times during the dry season and 2 times during the wet season. We placed three transects around the forest edge, each (9 transects), and plotted 1 m × 1 m plots. Data collection was carried out at distances of 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 m on each transect. In each plot, the composition of the understory vegetation cover, litter cover and soil bare was observed. The research was also observed canopy openness and collected rainfall data for one year from the nearest Meteorology station. Species found were recorded for identification based on origin, life form, original habitat, and seed dispersal. The study‘s results found 57 species, 16 species only in DS, then 17 species only in WS, and 24 in both seasons. The dynamics of changes in these species are influenced by the season, which will affect the environment around the plant. Seasonal differences impact light intensity, canopy openness, leaf fall and growth, and litter thickness, which impact the understory diversity and abundance.

Elevation-Dependent Natural Regeneration of Abies georgei var. smithii Forest in Southeastern Tibet

The comprehensive impacts of biotic and abiotic factors on the natural regeneration of Abies georgei var. smithii (Abies) forests in Tibet are not thoroughly understood. To address this gap, our study focused on the regeneration densities of Abies seedlings, saplings, and small trees across 21 plots (each 20 m × 20 m) along an elevation gradient from 3730 m to 4330 m in the Sygera Mountains of Southeastern Tibet. We meticulously measured a suite of 11 variables that describe stand structures and ecological conditions. Through analyses using Spearman’s correlation analysis, hierarchical partitioning, and multiple linear regression, we identified key ecological drivers for successful Abies regeneration. Our results highlighted a peak in the abundance of seedlings, saplings, and small trees at an elevation of 3930 m. As the elevation rose from 3730 m to 4330 m, we observed an initial increase followed by a decrease in canopy cover (canopy), mother tree density (MotherT), 1000-seed weight (SeedW), litter thickness (LitterT), moss cover (MossC), moss thickness (MossT), soil moisture (SM), and soil bulk density, while mean annual temperature and soil depth to permafrost consistently decreased. The critical ecological drivers for Abies natural regeneration were identified as follows: MossT was pivotal for seedling density; canopy and MossC were influential for sapling density, and MotherT was the main factor affecting the density of small trees. This study suggests that a high density of mother trees and a thick and highly covered layer of moss are conducive to the natural regeneration of Abies in the Sygera Mountains. Understanding the current status of regeneration is vital for informing conservation and management strategies for Abies forests in Tibet.

Impact of land use history and soil properties on soil mite communities (Acari, Mesostigmata) inhabiting stands growing on post‐agricultural land

AbstractDecades of agriculture in a former—type of ecosystem, for example, deciduous forests—result in severe habitat degradation. The planted tree species encounter harsh conditions due to physically and chemically transformed soil environments. In addition, afforestation itself significantly modifies the upper soil horizons. It may impact the soil fauna communities, including mites from the Mesostigmata order (Mesostigmata = Gamasida). Due to their sensitivity, mesostigmatid mites are good bioindicators of changes in the soil. A decrease in the density, species richness, and diversity of mites indicates disturbances in the soil environment and may confirm the impact of agricultural practice on the soil environment. Our research aim was to examine the impact of soil properties and land use history on the mesostigmatid mite communities in stands growing on forest and post‐agricultural lands. These sites were afforested with different tree species (Betula pendula Roth., Fagus sylvatica L., Pinus sylvestris L., and Quercus robur L.). Thus, 21 research plots were established on forest and post‐agricultural land, each on rusty soils considered to be one of the most common in Central European forests. We collected a total of 567 soil samples during three sampling sessions in spring and autumn for soil Mesostigmata investigation. We also described the soil profile on each plot and collected soil and litter samples to measure pH, litter thickness, soil organic matter, bulk density, soil moisture, soil organic carbon, and elements content. Our study revealed that 16 out of 30 environmental parameters differed between habitat types. A total of 1355 mites were classified into 58 taxa (50 species and 8 genera). The most numerous species were Veigaia nemorensis (165 ind.; 12.2% of all mesostigmatid mites), Zercon peltatus (156; 11.5%), and Paragamasus conus (141; 10.4%). The highest abundance was recorded in birch stands on forest land, whereas the lowest abundance for oak stands growing on post‐agricultural land. Interestingly, in oak stands we recorded both the highest diversity of mite communities (forest land) and the lowest on post‐agricultural land. Furthermore, our study showed that post‐agricultural land and Na content in forest litter affected the abundance, species richness, and diversity of mesostigmatid mite communities. Species richness was additionally affected by tree species, that is, pine and oak. Our research indicated that long‐term agricultural practice negatively affected the density, species richness, and diversity of Mesostigmata communities 20 years after afforestation.

Structural effects of reedbed grazing and its cessation on reed-nesting songbird densities

Reedbeds are crucial breeding habitats for vulnerable songbird species. Irrespective of their protection status, these habitats may be threatened by organic matter accumulation, progressively leading to structural homogenization and habitat succession towards woodland. Managers prevent excessive litter build-up with various interventions opening-up the reedbeds, such as grazing, which may be detrimental or suitable for some reed bird species. We assessed the effects of extensive grazing by horses and its cessation in the medium and long terms on reedbed structure, and the consequences on reed-nesting songbird densities in Estagnol Nature Reserve, a protected wetland near the French Mediterranean coast. We compared reedbed structural features between grazed, newly ungrazed and old-ungrazed plots. During nine years, we censused four songbird species in spring and collected water level data in the same survey plots. Grazing reduced reedbed extent, rejuvenated the vegetation with more short green stems on a thinner litter, and produced higher structural heterogeneity and discontinuity compared to long-lasting non grazing. Newly ungrazed plot showed intermediate effects. All surveyed songbird total densities were similar among plots while species numbers and densities differed. Grazed reedbed was more attractive to Moustached Warblers (Acrocephalus melanopogon) and Great Reed Warblers (Acrocephalus arundinaceus), likely due to the large edges and the high vegetation structural heterogeneity. However, Moustached Warblers were more negatively affected by higher water level in grazed reedbed, presumably because flooding prevents litter foraging. The newly ungrazed reedbed was not preferred by any species. All warbler species were found under low density in the old-ungrazed reedbed, where Reed Buntings (Emberiza schoeniclus) were exclusively found. Food availability related to thick litter layer may explain this predilection. Common Reed Warblers (Acrocephalus scirpaceus) were found everywhere in similar densities. We conclude that reedbed management by extensive horse grazing and also its long-term cessation may benefit several songbird species. Within a context of wetland degradation and disappearance, both management strategies are useful to establish and maintain suitable habitats for reed-nesting songbird communities.

Diversity and ecological dynamics of ground and understory arachnid spiders from a lowland tropical forest in Sumber Pawon, Kediri, East Java

Spiders have significantly contributed to the dynamics of terrestrial ecosystems and play an essential role as appropriate bio-indicators to monitor habitat changes. We aim to determine the composition and local scale diversity of spiders in the understory and ground layers and to determine habitat preferences regarding the distribution of spiders in the interior forests and riparian forests. Sampling was conducted at a protected forest area in Sumber Pawon Kediri, covering an area of 12.45 Ha during the wet season (January-March). The study’s results found 340 individuals consisting of 15 families and 63 species. Family Araneidae and species Hamadruas superba are the most common taxa groups in the interior forests, while Hippasa holmerae are in riparian forests. More individuals and species are found understorey shrubs in forest interiors. Soil temperature, relative humidity, and litter thickness positively correlate with spider abundance. Resource partitioning observation showed that leaf litter and herbaceous plants contain more potential prey for spiders. Forest habitat management programs must consider the spatial variation of spiders between strata, as well as the response of the spiders to the seasons. A better understanding of spider ecological dynamics will support the sustainable management of forest ecosystems.

Vegetation-cover control of between-site soil temperature evolution in a sandy desertland

Vegetation has an important influence on soil temperature (ST). However, the possible effects of surface vegetation on ST and their feedback on microclimate remain uncertain due to the lack of in-situ and long-term environmental records, especially for arid and semiarid regions of the world. A continuous, two-year study was implemented over a bare sand dune (BF) and two scrub-vegetation sites of variable cover in the Mu Us Desert of northwest China. Surface vegetation at the two non-bare sites varied from about 40% (moderate cover, MF) and 80 % (high cover, HF) of their respective surface area. Depiction of the vertical ST-profile was based on an array of field-based measurements taken within the uppermost 180 cm of the soil complex at each site. Compared with the BF site, mean ST at MF and HF decreased by 1.2 and 1.6 °C during the uniform thaw period and increased by 0.1 and 1 °C during uniform freezing. Amplitude of seasonal variation in ST for both vegetated sites, i.e., MF and HF, was reduced by 2.4 and 4.9 °C, respectively. As soil cooling during the uniform thaw period was greater than soil warming during uniform freezing, annual mean ST decreased at both vegetated sites by 1.6 and 1.2 °C (for MF and HF, respectively) compared to ST at BF. Differences in ST among the three sites during the uniform freeze and thaw periods were exponentially correlated with the extent of site vegetation cover, leaf area index, aboveground biomass, and on-the-ground litter thickness. Vegetation cover was shown to reduce the depth of the frost layer by 30 cm and prolonged the uniform thaw period by 1–35 days at the HF site. Mean daily STs at the center of each soil layer at the three sites were simulated with a two-equation model developed for this study, yielding a coefficient of determination (R2) of 0.91 when modeled STs were compared against their corresponding field observations. Increases in winter ST has potential to safeguard ground-dwelling grubs and other agriculturally harmful insects from freezing and dying. Likewise, decreases in annual ST could help promote decreases in litter decomposition, potentially lessening the effects of wind erosion.

Etçi Piliçlerde Pirinç Kabuğu Altlık Derinliğinin Besi Performansı, Ayak Taban Yangısı ve Et Kalite Özellikleri Üzerine Etkisi

This study was carried out to determine the effect of rice hulls used as litter in two different thicknesses (5 and 10 cm) on fattening performance, mortality rate, foot pad lesions, meat quality and meat color characteristics of Ross 308 chickens. Rice hulls of 5 cm (T5) and 10 cm (T10) thickness were laid on the coops that were similar in size and design. Fattening performance, FCR (feed conversion ratio), mortality rate, foot pad lesions, meat quality, and meat color characteristics were determined in three consecutive fattening periods. It was determined that the feed conversion ratios were 1.748 and 1.577 in the T5 and T10 groups, respectively, and the difference was significant (P0.05). On the other hand, it was determined that the difference between foot pad lesion scores within the litter thickness groups was significant (P