Afforestation Practices Research Articles

Variation and coordination among the plant functional traits of three coexisting shrub species in arid conditions

Functional traits are critical indicators for assessing and predicting plant environmental adaptations and survival strategies. However, less attention has been paid to root functional traits due to the costly and destructive nature of field excavations. This has resulted in a poor understanding of organ trait associations and vegetation survival strategies, particularly for plants in arid environments. In this study, we investigated 11 classical plant functional traits (leaf, stem, and root) and the intact root systems of three dominant coexisting shrubs, Calligonum mongolicum, Nitraria sphaerocarpa, and Haloxylon ammodendron, in a typical oasis–desert ecotone in northwestern China. These three coexisting shrubs generally converge on conservative resource strategies with dimorphic root systems and small leaf mass fractions to cope with strong habitat filtering and survive in arid environments. However, we found significant interspecific divergences in functional traits. Specifically, C. mongolicum had the most conserved traits, the medium root depth (370 cm), and the highest root-shoot ratio (1.72). H. ammodendron had relatively conserved traits, with the most extensive root depth (420 cm, access to groundwater) and the lowest root–shoot ratio (0.45). N. sphaerocarpa had the least conservative traits, the shallowest root depth (200 cm), and the medium root–shoot ratio (1.14). These divergences promote ecological niche segregation and ensure the stable coexistence of shrubs in this resource-limited environment. In contrast to the whole-plant economics spectrum, there was limited coordination between aboveground and belowground functional traits across the three species. Therefore, it is speculated that the different organs of these three species may operate independently to manage different constraints. The deep-rooted H. ammodendron is highly dependent on groundwater; therefore, planting them extensively in the ecotone may increase local groundwater consumption, resulting in the severe degradation of these species, particularly in the context of consecutive oasis expansion and intensified climate change. These results are expected to contribute to the development of effective ecosystem restoration and afforestation practices in such oasis–desert ecotones.

Mixed forests provide higher levels of growth and yield than monocultures across a broad range of conditions

Compared with single-species forests, mixed forests tend to provide more forest ecosystem functions and services. However, there is a lack of detailed understanding of the basic mechanisms of the impact of species diversity on tree growth and forest productivity. The main drivers of this relationship are also still under discussion. Here, we synthesized information from 93 studies to quantify the increase in tree size, crown size and stand productivity in mixed stands, and conducted a meta-analysis on the response of tree growth and forest productivity to species mixing. Tree size, crown size and stand productivity increased by 7.4 % (2.4–12.5 %), 12.6 % (5.6–20.1 %), and 33.0 % (18.7–49.0 %), respectively, in mixed stands compared with single-species stands. Our results show that when all observations are included, the mean effect sizes of tree size, crown size, and stand productivity were greater than when only the equal stand density observations were included. Stand age and stand density were the most important moderators affecting tree size in mixed forests. Stand age, shade tolerance and soil acidity were the most important moderators influencing the effect sizes of crown size, and shade tolerance was the most important moderator influencing the effect sizes of stand productivity. We found that these positive mixing effects were also modulated by tree functional traits, stand characteristics, and climatic conditions. For different growth variables, the moderators that affect their growth in the mixed forests were different. Therefore, in the afforestation practices for differing management objectives, foresters should give priority to the factors that have the most important impact on them to achieve their goals. Our results have implications for linking biodiversity-ecosystem functioning relationships and forest management practices and may aid the development of more appropriate afforestation strategies.

Impact of Land Use and Climate Change on Streamflow: An Assessment Using a Semi-Empirical Model in the Guishui Watershed of North China

Land-use change may significantly influence streamflow. The semi-empirical model PhosFate was used to analyze the impact of land use and climate change on streamflow by choosing the Guishui watershed as a pilot site and then expanding, applying it to all of North China. The Guishui watershed (North Beijing, China) has experienced a dramatic decline in its streamflow in recent decades. Parallel to this, significant land-use change has happened in this area; afforestation programs have increased forest cover from 41% (1980) to 59% (2013) and a similar increase in forest cover can also be observed in North China. Managing flow decline requires separating climatic and direct human-influenced effects. The results showed the following: (1) Afforestation is a major factor that decreased total flow in the Guishui watershed from 1996 to 2014; total flow increased by around 24% more than the actual dataset in the constant scenario (no afforestation) and decreased by 5% more than the actual dataset in the forest scenario (all agriculture land use transferred to forests). (2) When forest coverage increases, the Qinghai–Tibet Plateau and the Loess Plateau are the most sensitive areas regarding total flow in North China; the total flow change rate increased by up to 25% in these two areas when land use shifted from sparse vegetation to mixed forests. After analyzing the contributions of these two factors, we formulated recommendations on future afforestation practices for North China. In the central–north and northwest districts, the annual precipitation is under 520 mm and 790 mm, respectively, and the practice of afforestation should be more carefully planned to prevent severe damage to streams. This research also proved that the PhosFate model can be used in North China, which would be a practical tool for watershed management.

Maximizing Climate Solutions: Assessing Forest Plantation Productivity and Carbon Sequestration Potential of Tree Species

Climate change is projected to negatively impact forest ecosystems and related industries, emphasizing the urgency of effective mitigation strategies. Forests play a crucial role in climate change mitigation by sequestering carbon dioxide (CO2). Planting trees can contribute significantly, absorbing tonnes of CO2 annually and limiting climate change impacts. This process underscores the vital contribution of forests to mitigating climate change. The aim is to evaluate the role of forest plantation productivity in mitigating climate change and assess the carbon dioxide sequestration potential of some tree species. The carbon dioxide (CO2) sequestration potential of the tree plantations was highest in the moist semi-deciduous north-west (MSDNW) zone followed in a decreasing order by the dry semi-deciduous (DSD) and forest-savannah transition (FST) zones with the values being 23.02 ± 21.84 (SD), 11.16 ± 6.00 and 9.25 ± 5.25 Mg CO2eq ha-1 year-1, respectively. For the various tree species plantations, the CO2 sequestration potential exhibited by Cedrela odorata, mixed species and Tectona grandis stands was given as 36.93 ± 31.21 (SD), 19.06 ± 11.99 and 8.98 ± 4.67 Mg CO2eq ha-1 year-1, respectively. The comprehensive findings underscore the need for nuanced strategies in climate change policies and afforestation initiatives. Sustainable forest management, tailored afforestation practices are recommended to optimize forest plantation contributions to global climate goals.

Spatiotemporal variation and controlling factors of dried soil layers in a semi-humid catchment and relevant land use management implications

The formation of dried soil layers (DSLs) is a broad consequence of climate change (i.e., through temperature increases and/or precipitation decreases) and poor land management practices, where these layers exist has severe negative effects (i.e., retardation of vegetation, negative water cycle balance) on the sustainability of restored ecosystems and health of agriculture. Because of the effort and time required, only sporadic in situ measurements on spatial and temporal DSL variation have been reported, particularly at a catchment scale. However, this information is essential for understanding mechanisms associated with evolutionary DSL processes as well as developing effective land management techniques. Accordingly, this study monitored soil water content to a 5 m depth over a 5-year period in a semi-humid catchment on the Loess Plateau while also investigating temporal DSL dynamics and dominant controls. In the semi-humid catchment, DSLs occurred at 90.7 % of all sampling sites. Spatially and temporally averaged DSL formation depth (DSLFD), DSL thickness (DSLT), and DSL soil water content (DSL-SWC) within the 0–5 m profile were 170 cm, 262 cm, and 9.52 %, respectively. Forest and shrubland DSL regimes were drier than those of grassland. These three DSL indices exhibited significant correlation with temperature variables, while only DSLFD variables significantly correlated to precipitation. Land use type was the predominant control of DSL variation at a catchment scale. A spatial DSLT variation comparison under different land use treatment positions determined the feasibility of planting grass at an upslope position and mixed forest/shrubland + grass at mid-slope and downslope positions in the semi-humid catchment, which provides a good case study for afforestation practices at a catchment scale. Findings from this study are intended to aid in catchment soil and water conservation, soil drought mitigation, and sustainable vegetation management practices on the Loess Plateau as well as other water-limited regions worldwide.

A novel approach to determine spatial prioritization of flooding mitigation practices based on coupled hydrodynamic and rainfall-tracking model

Abstract This article is focused on proposing a novel approach to determining flood mitigation practices based on coupled hydrodynamic and rainfall-tracking models. V-shaped and Baogaisi catchments were applied to assess the effects of the novel approach in mitigating peak discharge and runoff volume, respectively. Specifically, traditional afforestation scenarios were planned from downstream to upstream, while novel afforestation scenarios were designed based on the maximum and minimum contribution rate of sub-areas. Then two types of cases were simulated by the coupled hydrodynamic and rainfall-tracking model again to evaluate the mitigating effects of different afforestation practices. Results show that the coupled model is able to obtain accurate hydrodynamic and rainfall-tracing information simultaneously within each computing grid under the flooding caused by rainfall events. Moreover, in comparison with the reduction effects of traditional cases, results simulated under two catchments illustrated that the novel approach is able to determine spatial prioritization of afforestation management practices. In particular, there is a positive correlation between the contribution rate of afforestation area and the reduction effect of runoff volume caused by rainfall events. Thus, the research could provide a more scientific and reasonable guide in determining spatial prioritization flooding mitigation practices for planners and governments.

Enhancing Afforestation Practices in Hilly Terrain: A Study on Soil Disturbance by Earth Augers Based on the Discrete Element Method

Afforestation operations in hilly regions are both arduous and unsafe. The mechanized afforestation method that takes into account soil and water conservation measures is deemed highly important. This paper examines the operational process and the auger’s mechanism of digging below the ground using the discrete element method (DEM). Using this model, soil disturbance parameters and reaction forces are satisfactorily predicted, exhibiting similar trends to experimental observations. This research also examines the influence of key parameters on soil disturbance and distribution patterns and analyzes the conditions and mechanisms of the formation of fish-scale pits to preserve soil and water. A field experiment of pit digging in woodland is carried out to test the performance of the device. The error rates for the actual and simulated values of the efficiency of conveying soil and the distance of throwing soil on plain terrain and slopes were 12.7% and 8.2%, and 8.6% and 15.7%, respectively. Overall, this research provides a theoretical basis for the innovative exploration, development, and optimized design of earth augers in hilly regions.

Analyzing Land Use/Land Cover Changes Using Google Earth Engine and Random Forest Algorithm and Their Implications to the Management of Land Degradation in the Upper Tekeze Basin, Ethiopia.

Land use and land cover change (LULCC) without appropriate management practices has been identified as a major factor contributing to land degradation, with significant impacts on ecosystem services and climate change and hence on human livelihoods. Therefore, up-to-date and accurate LULCC data and maps at different spatial scales are significant for regular monitoring of existing ecosystems, proper planning of natural resource management, and promotion of sustainable regional development. This study investigates the temporal and spatial dynamics of land use land cover (LULC) changes over 31 years (1990-2021) in the upper Tekeze River basin, Ethiopia, utilizing advanced remote sensing techniques such as Google Earth Engine (GEE) and the Random Forest (RF) algorithm. Landsat surface reflectance images from Landsat Thematic Mapper (TM) (1990, 2000, and 2010) and Landsat 8 Operational land imager (OLI) sensors (2021) were used. Besides, auxiliary data were utilized to improve the classification of LULC classes. LULC was classified using the Random Forest (RF) classification algorithm in the Google Earth Engine (GEE). The OpenLand R package was used to map the LULC transition and intensity of changes across the study period. Despite the complexity of the topographic and climatic features of the study area, the RF algorithm achieved high accuracy with 0.83 and 0.75 overall accuracy and Kappa values, respectively. The LULC change results from 1990 to 2021 showed that forest, bushland, shrubland, and bareland decreased by 12.2, 24.8, 1.2, and 15.4%, respectively. Bareland has changed to farmland, settlement, and dry riverbed and stream channels. Expansion of dry stream channels and sandy land surfaces has been observed from 1990 to 2021. Bushland has shown an increment by 17.2% from 1900 to 2010 but decreased by 19.5% from 2010 to 2021. Throughout the study period, water, farmland, dry stream channels and riverbeds, and urban settlements showed positive net gains of 484, 8.7, 82, and 26778.5%, respectively. However, forest, bush, shrub, and bareland experienced 12.17, 24.8, 1.2, and 15.37% losses. The observed changes showed the existing land degradation and the future vulnerability of the basin which would serve as an evidence to mitigate land degradation by avoiding the future conversion of forest, bushland, and shrubland to farmland, on the one hand, and by scaling up sustainable farmland management, and afforestation practices on degraded and vulnerable areas, on the other hand.

Effects of drought hardening on the carbohydrate dynamics of Quercus acutissima seedlings under successional drought.

As precipitation patterns are predicted to become increasingly erratic, the functional maintenance of warm-temperate forests constitutes a key challenge for forest managers. In this study, 2-year-old Quercus acutissima seedlings were selected to elucidate the mechanisms whereby they respond to soil water fluctuations and the drought hardening effects on plant carbohydrate dynamics. Seedlings were trained under different soil water conditions for 2 months: drought (D), well-watered (W), 1-month drought and then 1-month well-watered (D-W), and 1-month well-watered and then 1-month drought (W-D). The functional traits involved in water- and carbon-use strategies were explored at the end of the hardening period. Compared with seedlings in group W, seedlings in groups D, D-W, and W-D had increased potential for carbon uptake (i.e., light saturated point, maximum ribulose-1,5-bisphosphate (RuBP) saturated rate, and electron transport rate) and water uptake (i.e., fine root-to-coarse root ratio) and downregulated growth and mitochondrial respiration to decrease carbon consumption. After water fluctuation hardening, we performed a successional dry-down experiment for 1 month to detect carbohydrate dynamics and explore the acclimation caused by prior hardening. Our results revealed that there were more soluble sugars allocated in the leaves and more starch allocated in the stems and roots of seedlings hardened in the D, W-D, and D-W treatments than that of seedlings hardened in the W treatment. No significant changes in total non-structural carbohydrates were found. In addition, we found near-zero (seedlings trained by D and D-W treatments) or negative (seedlings trained by W-D treatment) growth of structural biomass at the end of the dry-down experiment, which was significantly lower than that of W-hardened seedlings. This suggests that there was a shift in allocation patterns between carbon storage and growth under recurrent soil drought, which can be strengthened by drought memory. We conclude that Q. acutissima seedlings adjusted water- and carbon-use strategies in response to water fluctuations, whereas stress memory can enhance their overall performance in reoccurring drought. Therefore, taking advantage of stress memory is a promising management strategy in forest nurseries, and drought-trained seedlings might be more suitable for afforestation practices in sites characterized by fluctuating soil water content, considering the ongoing global climatic changes.

PuHox52 promotes coordinated uptake of nitrate, phosphate, and iron under nitrogen deficiency in Populus ussuriensis.

It is of great importance to better understand how trees regulate nitrogen (N) uptake under N deficiency conditions which severely challenge afforestation practices, yet the underlying molecular mechanisms have not been well elucidated. Here, we functionally characterized PuHox52, a Populus ussuriensis HD-ZIP transcription factor, whose overexpression greatly enhanced nutrient uptake and plant growth under N deficiency. We first conducted an RNA sequencing experiment to obtain root transcriptome using PuHox52-overexpression lines of P. ussuriensis under low N treatment. We then performed multiple genetic and phenotypic analyses to identify key target genes of PuHox52 and validated how they acted against N deficiency under PuHox52 regulation. PuHox52 was specifically induced in roots by N deficiency, and overexpression of PuHox52 promoted N uptake, plant growth, and root development. We demonstrated that several nitrate-responsive genes (PuNRT1.1, PuNRT2.4, PuCLC-b, PuNIA2, PuNIR1, and PuNLP1), phosphate-responsive genes (PuPHL1A and PuPHL1B), and an iron transporter gene (PuIRT1) were substantiated to be direct targets of PuHox52. Among them, PuNRT1.1, PuPHL1A/B, and PuIRT1 were upregulated to relatively higher levels during PuHox52-mediated responses against N deficiency in PuHox52-overexpression lines compared to WT. Our study revealed a novel regulatory mechanism underlying root adaption to N deficiency where PuHox52 modulated a coordinated uptake of nitrate, phosphate, and iron through 'PuHox52-PuNRT1.1', 'PuHox52-PuPHL1A/PuPHL1B', and 'PuHox52-PuIRT1' regulatory relationships in poplar roots.

Comparative study of biomass and morpho-physiological traits for different deciduous species in semi-arid afforestation region of Mongolia

Afforestation practices are useful tools for rehabilitating degraded lands in many parts of the world, as well as in Mongolia for protecting soil, water resources, and the potential of carbon sequestration to mitigate climate change. And so, regular investigation was conducted to determine the response and adaptation of Populus sibirica, Ulmus pumila, and Hippophae rhamnoides in terms of growth characteristics and leaf morpho-physiological traits to suggest and select effective and sustainable afforestation methods to suit Mongolia’s conditions. We measured the root collar diameter (RCD), height growth, leaf area (LA), specific leaf area (SLA), leaf biomass (LB), chlorophyll concentration and leaf water potential (ψ) of the selected species. Results showed that P. sibirica (135.3±6.81cm) height growth, stem, root and total biomass were higher among the studied species, but leaf and branch biomass was higher in U. pumila (93.46±5.10cm). However, leaf morphological parameters and chlorophyll content was higher for P. sibirica (330.56±56.81µg/ml) compared with other species. Leaf water potential was found lower for U. pumila and higher in H. rhamnoides. Therefore, we suggest that U. pumila is more adaptable to low mean annual precipitation regions, requiring less water and H. rhamnoides provide good financial source for local community as they yield fruits. Our findings are relevant to ensuring the sustainability of afforestation programs in semiarid conditions in Mongolia.

Effects of cropland abandonment and afforestation on soil redistribution in a small Mediterranean mountain catchment

In slopes of Mediterranean mid-mountain areas, land use and land cover changes linked to the abandonment of cropland activity affect soil quality and degradation and soil redistribution; however, limited attention has been paid to this issue at catchment scale. This paper evaluates the effects of cropland abandonment and post-land abandonment management (through natural revegetation and afforestation) on soil redistribution rates using fallout 137Cs measurements in the Araguás catchment (0.45 km2, Central Spanish Pyrenees). A total of 52 soil core samples, distributed in a regular grid, from the first 30–40 cm and 9 sectioned reference samples were collected across the catchment and soil properties were analysed. Fallout 137Cs was measured in a 5 cm sectioned references samples and in bulk grid samples. 137Cs inventories were used to estimate soil erosion and deposition rates across the catchment. Results show that the highest erosion rates were recorded under sparsely vegetated sites in the badland area, while the lowest rates were found in the afforested area, but no significant differences were observed between the different uses and covers in soil redistribution rates likely due to a long history of human intervention through cultivation in steep slopes and afforestation practices. However, the recovery of the soil organic matter in afforested areas suggest that afforestation can reduce soil degradation at long-term scale. The information gained achieve a better understanding of soil redistribution dynamics and provide knowledge for effective land management after cropland abandonment of agroecosystems in Mediterranean mountain areas.

Evaluation of mangrove rehabilitation and afforestation in the southern coasts of Iran

The increasing multiple ecosystem services of mangrove forests, especially in the coastal regions have highlighted a need for conservation and afforestation of these forests. However, economic development and activities on the coasts have generated severe pollution issues that caused irreparable damages to the areas and quality of mangrove forests. As a result, rehabilitating the affected areas and forest planting are increasingly important, whereby some form of an assessment is needed to determine their sustainable performance and effectives. This study has used the indicators of forest resource sustainability, and the sustainability of planting sites to evaluate mangrove plantings in Iran's southern coast. Findings showed that there was a total of 47 mangrove planting sites on the coasts of the three provinces studied with an area of 9584.5 ha. There were 26 afforestation practice sites with an area of 5724 ha, and 21 combined rehabilitation and afforestation practice sites with an area of 3860.5 ha identified in this study. Approximately 76.6% of planting sites had been lost and the remaining areas had experienced an average density drop of 44%. Results of the stability class analysis revealed that 23 planting sites were in an extremely unsustainable state, 15 sites were considered as highly unsustainable, six sites were in a state of tendency to be unsustainable, whereas only three sites were regarded as sustainable. Findings from this study can assist managers and decision makers to review the site selection processes and pattern of successful planting sites, to facilitate better site selection and enhance the monitoring of mangrove rehabilitation or afforestation.

Updated estimation of forest biomass carbon pools in China, 1977–2018

Abstract. China is one of the major forest countries in the world, and the accurate estimation of its forest biomass carbon (C) pool is critical for evaluating the country's C budget and ecosystem services of forests. Although several studies have estimated China's forest biomass using national forest inventory data, most of them were limited to the period of 2004–2008. In this study, we extended our estimation to the most recent period of 2014–2018. Using datasets of eight inventory periods from 1977 to 2018 and the continuous biomass expansion factor method, we estimated that the total biomass C pool and average biomass C density in Chinese forests increased from 4717 Tg C (1 Tg = 1012 g) in the period of 1977–1981 to 7975 Tg C in the period of 2014–2018 and 38.2 Mg C ha−1 to 45.8 Mg C ha−1 (1 Mg = 106 g), respectively, with a net increase of 3258 Tg C and an annual sink of 88.0 Tg C yr−1. Over the most recent 10 years (2009–2018), the average national forest biomass C density and C sink were 44.6 Mg C ha−1 and 154.8 Tg C yr−1, respectively, much larger than those of 39.6 Mg C ha−1 and 63.3 Tg C yr−1 in the period 1977–2008. These pronounced increases were largely attributed to afforestation practices, forest growth, and environmental changes. Our results have documented the importance of ecological restoration practices, provided an essential basis for assessing ecosystem services, and helped to achieve China's C neutrality target.

Soil Carbon Sequestration Potential of Terrestrial Ecosystems: Trends And Soil Priming Effects

Carbon sequestration in the terrestrial ecosystems by forest and agricultural management activities is being considered the best sustainable method to diminish the increasing concentration of atmospheric carbon dioxide (CO2). This paper presents soil carbon sequestration potential of terrestrial ecosystem and the concept of soil priming effect. According to forest survey of India, the carbon stock of Indian forests increased at the rate of 0.3% as compared to the previous assessment, i.e., from 2017 to 2019. Indian forests soils are a reservoir of 7124.6 million tonnes of carbon and they still have high potential to store more carbon. As per soil carbon 4 mille concepts, India must intensify the process of afforestation, land restoration, and agricultural management practices to increase the soil carbon storage, i.e., up to 0.4%. However, organic manure amendments or a fresh supply of carbon substrates via. rhizodeposits into the rainfed or irrigated lands changes the microbial communities and may decompose the already stored soil carbon, i.e., positive priming effect. Thus, accurate measurement of soil organic carbon (SOC) content in various types of ecosystems like forest, agricultural land, desert, agroforest, and plantation is still crucial to ascertain how much they can help to reduce the increasing concentration of atmospheric CO2.

Climate regulation ecosystem services and biodiversity conservation are enhanced differently by climate- and fire-smart landscape management

Abstract The implementation of climate-smart policies to enhance carbon sequestration and reduce emissions is being encouraged worldwide to fight climate change. Afforestation practices and rewilding initiatives are climate-smart examples suggested to tackle these issues. In contrast, fire-smart approaches, by stimulating traditional farmland activities or agroforestry practices, could also assist climate regulation while protecting biodiversity. However, there is scarce information concerning the potential impacts of these alternative land management strategies on climate regulation ecosystem services and biodiversity conservation. As such, this work simulates future effects of different land management strategies in the Transboundary Biosphere Reserve of Meseta Ibérica (Portugal-Spain). Climate-smart (‘Afforestation’, ‘Rewilding’) and fire-smart (‘Farmland recovery’, ‘Agroforestry recovery’) scenarios were modelled over a period of 60 years (1990–2050), and their impacts on climate regulation services were evaluated. Species distribution models for 207 vertebrates were built and future gains/losses in climate-habitat suitability were quantified. Results suggest climate-smart policies as the best for climate regulation (0.98 Mg C ha−1 yr−1 of mean carbon sequestration increase and 6801.5 M€ of avoided economic losses in 2020–2050 under Afforestation scenarios), while providing the largest habitat gains for threatened species (around 50% for endangered and critically endangered species under Rewilding scenarios). Fire-smart scenarios also benefit carbon regulation services (0.82 Mg C ha−1 yr−1 of mean carbon sequestration increase and 3476.3 M€ of avoided economic losses in 2020–2050 under Agroforestry scenarios), benefiting the majority of open-habitat species. This study highlights the main challenges concerning management policies in European rural mountains, while informing decision-makers regarding landscape planning under global change.

Differential responses of ground-active arthropod abundance and diversity to shrub afforestation in heterogeneous textured soils in desertified grassland ecosystems, North China

Shrub afforestation is an effective way for restoration of soil communities and desertification control in desertified regions. However, little is unknown about how heterogeneous textured soils influence the effectiveness of shrub afforestation on the activities and diversity of ground-active arthropods. In the present study, ground-active arthropods were examined by pitfall trapping as well as by herbaceous performances and soil properties investigated in two shrub microhabitats (the shrub canopy and open spaces) in afforested sandy soil and sandy loam soil of northwestern China. The adjacent shifting sandy land, not covered by shrub plantations, served as a control. Total abundance in the open spaces in afforested sandy soil was significantly (p < 0.05) higher than those in the shrub canopy microhabitats in the same soil type and was also higher than those in both shrub microhabitats (open space and shrub canopy) in afforested sandy loam soil. A consistently (p < 0.05) greater taxa richness and the Shannon index as well as taxa richness of trophic groups (phytophages and predators) was found in shrub microhabitats in both soil types compared to the shifting sandy land. However, no significant differences (p > 0.05) were observed in taxa richness, Shannon index, and the Simpson index of ground-active arthropods, and in the abundance and richness of both trophic groups among the four shrub microhabitats in both soil types. In conclusion, soil textural heterogeneity in terms of soil type had a significant effect on the abundance, but not on the biodiversity distribution and trophic relationship, of ground-active arthropods between shrub microhabitats. The facilitative effect of shrubs benefited a stable biodiversity distribution and thus a stable trophic relationship within ground-active arthropod communities through afforestation practices, regardless of soil type.

Restoration success in afforestation sites established at different times in arid lands of Central Anatolia

Restoration of degraded lands is among the major challenges in Arid and semi-arid ecosystems. Therefore, in many regions where arid and semi-arid climates prevail, afforestation studies are carried out for restoration purposes. This study evaluated long-term afforestation practices in terms of ecosystem restoration in the arid lands of Central Anatolia, Turkey. For the study, sample afforestation sites of different ages were chosen in the Tuz Gölü-Konya basin. Species in the sites included black pine (Pinus nigra), Russian olive (Elaeagnus angustifolia), sweet almond (Prunus dulcis), black locust (Robinia pseudoacacia), narrow-leaved ash (Fraxinus angustifolia), and mahaleb cherry (Prunus mahalep). For each sampling area, the survival rates, height, and diameter values of species were recorded. Litter on the forest floor was sampled and then representative soil pits were dug at each site to sample soil from different layers (30, 60, 90, and 120-cm deep) of the profile. Bulk density, texture, lime content, pH, salinity, cation exchange capacity (CEC), and carbon (C) and nitrogen (N) concentration were determined for each soil sample. Approximately 2/3 of the black pine seedlings had died in the first 8–10 years of afforestation. The mortality rate in almond and mahaleb seedlings was approximately 20%. After 25–27 years of afforestation, 1/3 and 2/3 of the initial almond and Russian olive seedlings were lost, respectively. The mortality rate for other species was about 80% for the same period. Black pine had reached over 6.5 m, increasing its height by about 11-fold over the last 10–25 years. In the same period, the increase in the height of black locust was 2.8-fold, almond 2.6-fold, and ash 2.5-fold. The least height growth (1.7-fold) for this period was recorded for mahaleb. The amount of litter had increased 3- and 5-fold, at 15–17 years and 25–27 years of plantation age, respectively, compared to its increase in the open control site. After 15 years from planting, soil nitrogen (N) concentration at the first 30-cm depth had increased by about 1/3 compared to the open area. At the same depth, the soil pH value had decreased by 0.15 units after 25–27 years compared to the rest of the profile. These data implied that soil restoration had been initiated at all sites.

Identifying the drivers of water yield ecosystem service: A case study in the Yangtze River Basin, China

The Yangtze River Basin (YRB) is a region of vital economic and ecological importance in China, facing challenges of water scarcity and flooding underpinned by complex, yet underexplored, interactions between anthropogenic and biophysical changes. This study conducted a multi-scale analysis to (i) quantitatively evaluate the spatio-temporal patterns of the water yield ecosystem service of the whole of YRB from 2000 to 2015 using the InVEST model and (ii) investigate the interactive influence of climate, land-use, landscape, and socio-economic factors on the sub-watershed level water yield using the automatic linear and geographically weighted regression modelling. The results pinpointed regions of high and increasing water yield in the southeast of YRB, and that of low and decreasing water yield in the northwest. The YRB’s water yield was found to, in particular, be associated with the average annual precipitation and the extent of the urban area. We identified three interaction effects, which suggest that fostering connected patches in afforestation practices, maintaining slow-pace enhancement in compact urban development and improving the regularity of cropland’s shape in small-scale agriculture development are necessary to sustain the supply of water yield ecosystem service. Our study provides new insights into the joint effects of anthropogenic and biophysical factors underpinning the supply of YRB’s water yield ecosystem service, and sheds light on the indirect pathways of managing water resources via controlling local-level landscape metrics.

Research on Species Diversity of Pinus radiata Plantation under Different Afforestation Models in Dry-hot Valley of the Minjiang River

According to the field experiment, the species diversity of Pinus radiata pure forest, Pinus radiata and Cupressus chengiana mixed forest, Pinus radiata, Cupressus chengiana and Robinia pseudoacacia mixed forest was studied in Wenchuan, Lixian and Maoxian dry-hot valleys of the Minjiang River. The results showed that: (1) Ailanthus altissima was the common accompanying tree species in the tree layer of P. radiata plantation, Lespedeza bicolor was the dominant species in the shrub layer, and Artemisia had great regeneration potential in the herb layer. The species richness was in the order of herb layer > shrub layer > tree layer, and Asteraceae, Gramineae and Leguminosae were the dominant species under the forest. (2) During the time of 5—20 years, with the extension of time, the growth of average tree height and diameter at breast height (DBH) of P. radiata pure forest increased, but the number of shrub and herb species and vegetation coverage decreased gradually. The growth of average tree height and DBH of P. radiata and C. chengiana mixed forest was low, and the number of shrub and herb species under the forest had little change. The growth of average tree height and DBH of P. radiata, C. chengiana and R. pseudoacacia mixed forest increased slowly, but the species diversity and biomass of shrub and herb under the forest showed an upward trend. (3) In the practice of afforestation in the dry-hot valley of the Minjiang River, P. radiata, C. chengiana and R. pseudoacacia mixed forests with suitable density could be used as the main afforestation model. For the P. radiata pure forests to be tending, native tree species such as R. pseudoacacia, A. altissima and L.bicolor were preferred to be replanted after thinning to increase species diversity.