Conversion Of Natural Forest Research Articles

Land-use-driven change in soil labile carbon affects microbial community composition and function

The conversion of natural forests to plantations can lead to a substantial loss of soil organic carbon (SOC) and threaten the function of soil microbial communities. However, the effect of forest conversion on the relationship between SOC dynamics and shifts in the composition and function of the microbial community remain poorly understood, although such information is critical for predicting the long-term effect of land-use change on global SOC dynamics and storage. To fill this knowledge gap, our study investigated the influence of two decades of converting natural forest to a tea plantation on SOC storage, microbial community composition, C-degrading enzyme activity and the abundance of C-degrading microbial functional genes in a subtropical region in China. Two decades after converting natural forest to tea plantation, SOC storage decreased by 30%, and labile SOC [including easily mineralized C (Cmin), readily oxidizable C (ROC), dissolved organic C (DOC), and microbial biomass C (MBC)] decreased by 21–71%. Land-use change decreased the relative abundance of copiotrophic bacteria but increased the relative abundance of oligotrophic bacteria and lignin-degrading fungi. This resulted in a decrease in cellulase activity and cbhI gene abundance involved in cellulose degradation and conversely an increase in ligninase activity involved in lignin degradation after the conversion. Such shifts in microbial community composition and function associated with land-use change were mediated by the decrease in the labile C pool rather than the total SOC. Our study provided new insights into not only shifts in microbial communities but also specific C functional genes and related enzymes after forest conversion. These findings highlight that labile SOC, as an important functional soil component for microbial communities, significantly affects SOC dynamics and storage.

Land-use systems regulate carbon geochemistry in the temperate Himalayas, India

The Himalayan ecosystem is critical for ecological security and environmental sustainability. However, continuous deforestation is posing a serious threat to Himalayan sustainability. Changing land-use systems exert a tenacious impact on soil carbon (C) dynamics and regulate C emissions from Himalayan ecosystem. Therefore, this study was conducted to determine the changes in different C pools and associated soil properties under diverse land-use systems, viz. natural forest, natural grassland, maize field converted from the forest, plantation, and paddy field of temperate Himalaya in the surface (0–20 cm) and subsurface (20–40 cm) soils. The highest total organic carbon (24.24 g kg−1) and Walkley-black carbon contents (18.23 g kg−1), total organic carbon (45.88 Mg ha−1), and Walkley-black carbon stocks (34.50 Mg ha−1) were recorded in natural forest in surface soil (0–20 cm depth), while soil under paddy field had least total organic carbon (36.45 Mg ha−1) and Walkley-black carbon stocks (27.40 Mg ha−1) in surface soil (0–20 cm depth). The conversion of natural forest into paddy land results in 47.36% C losses. Among the cultivated land-use system, minimum C losses (29.0%) from different pools over natural forest system were reported under maize-filed converted from forest system. Land conversion causes more C losses (21.0%) in surface soil (0–20 cm depth) as compared to subsurface soil. Furthermore, conversion of forest land into paddy fields increased soil pH by 5.9% and reduced total nitrogen contents and microbial population by 28.0% and 7.0%, respectively. However, the intensity of total nitrogen and microbial population reduction was the lowest under maize fields converted from the forest system. The study suggested that the conversion of natural forest to agricultural land must be discouraged in the temperate Himalayan region. However, to feed the growing population, converted forest land can be brought under conservation effective maize-based systems to reduce C loss from the intensive land use and contribute to soil quality improvements and climate change mitigation.

Assessment of land use changes in the Verde River basin using two hydrological models

Land use changes can affect hydrological cycle dynamics, mainly groundwater recharge and infiltration-runoff relationships. The objective of this study was to evaluate the application of the Variable Infiltration Capacity (VIC) and Lavras Simulation of Hydrology (LASH) hydrological models and analyse the impacts of land use changes on the hydrological regime in the Verde River basin of southeastern Brazil. The land use change scenarios were developed considering demographic, agricultural and economic indicators as follows: 20% (S1) and 50% (S2) conversion of pasture into eucalyptus; 20% (S3) and 50% (S4) conversion of native forest into pasture; and 20% conversion of pasture into forest (S5). The CNS (Nash-Sutcliffe) values varied from 0.77 to 0.88 for daily and monthly fit during calibration (1993–1999) and validation (2000–2005) periods. The LASH model showed a better capacity to reproduce the regular streamflow regime than the VIC model. The reforestation scenarios (S1, S2, and S5) showed a decrease in total runoff, mainly due to the increase in evapotranspiration and canopy interception, while the deforestation scenarios (S3 and S4) showed the opposite effects. Differences in the structure and representation of hydrological processes in hydrological models must be considered to predict the impacts of land use changes on the hydrology of tropical and subtropical basins.

Cryptosporidium spp. and Giardia spp. in wild rodents: using occupancy models to estimate drivers of occurrence and prevalence in native forest and exotic Pinus radiata plantations from Central Chile

The conversion of native forest to forestry plantations is a worldwide practice, affecting biodiversity and host-parasite interactions. One of the most common timber plantations in the world are monocultures of Monterey pine (Pinus radiata). Using occupancy models, we analyzed the occurrence and prevalence of Cryptosporidium spp. oocysts and Giardia spp. cysts in fecal samples of wild rodents from a landscape dominated by extensive Monterey pine plantations in central Chile. We aimed to assess drivers of parasite infection such as habitat type, abundance of rodent hosts, species richness, and season. Small mammals were sampled seasonally for two years in three habitat types: native forests, adult pine plantations and young pine plantations. A total of 1091 fecal samples from seven small mammal species were analyzed by coprological analysis. Occurrence probability of Cryptosporidium spp. and Giardia spp. was similar for the most abundant rodent species (Abrothrix longipilis, A. olivacea, and Oligoryzomys longicaudatus) and for all habitat types. For Cryptosporidium spp., variation in prevalence was mostly explained by season with higher prevalence during winter season and lower during spring. For Giardia spp., the prevalence was significantly higher in young pine plantations, followed by adult pine plantations and native forests. In addition, higher prevalence of Giardia spp. was associated with lower host richness, suggesting a possible dilution effect. Our findings reveal that Monterey pine plantations increase Giardia spp. transmission among rodents, but has no clear effect on Cryptosporidium spp., providing evidence that the impact of land use on parasitism can be idiosyncratic. Since both parasites have zoonotic potential, our findings may be useful for land use planning and management considering health issues.

History of Land Cover Change on Santa Cruz Island, Galapagos

Islands are particularly vulnerable to the effects of land cover change due to their limited size and remoteness. This study analyzes vegetation cover change in the agricultural area of Santa Cruz (Galapagos Archipelago) between 1961 and 2018. To reconstruct multitemporal land cover change from existing land cover products, a multisource data integration procedure was followed to reduce imprecision and inconsistencies that may result from the comparison of heterogeneous datasets. The conversion of native forests and grasslands into agricultural land was the principal land cover change in the non-protected area. In 1961, about 94% of the non-protected area was still covered by native vegetation, whereas this had decreased to only 7% in 2018. Most of the agricultural expansion took place in the 1960s and 1970s, and it created an anthropogenic landscape where 67% of the area is covered by agricultural land and 26% by invasive species. Early clearance of native vegetation took place in the more accessible—less rugged—areas with deeper-than-average and well-drained soils. The first wave of settlement consisted of large and isolated farmsteads, with 19% of the farms being larger than 100 ha and specializing in diary and meat production. Over the period of 1961–1987, the number of farms doubled from less than 100 to more than 200, while the average farm size decreased from 90 to 60 ha/farmstead. Due to labor constraints in the agricultural sector, these farms opted for less labor-intensive activities such as livestock farming. New farms (popping up in the 1990s and 2000s) are generally small in size, with <5 ha per farmstead, and settled in areas with less favorable biophysical conditions and lower accessibility to markets. From the 1990s onwards, the surge of alternative income opportunities in the tourism and travel-related sector reduced pressure on the natural resources in the non-protected area.

Impact of forest–pasture conversion on soil physical and chemical properties

The objective of this paper is to assess the changes in soil physical and chemical properties resulting from the conversion of native forest to pasture and pasture to secondary forest in the state of Santa Catarina, Brazil. Seven forest–pasture successional stages were identified using aerial photographs and satellite images acquired in 1957, 1978, and 2008. Successional stages were coded as FFF, FPF, PFF, PPF, FPP, FFP, and PPP, where the first, second, and third letters refer to the land uses (P, pasture; F, forest) practiced in 1957, 1978, and 2008, respectively. Soil samples were collected by layer at depths of 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm. Clay contents, soil bulk density (Db), macroporosity (MP), microporosity (mP), pH, Aluminum (Al), cation exchange capacity (CEC), calcium (Ca), potassium (K), phosphorus (P), total organic carbon (TOC) content, carbon stock, and δ13C abundance were quantified. Conversion of forest to pasture increased soil P, K, Ca, Db, and mP; and reduced MP, TOC content, and carbon stocks. The largest carbon stocks occurred in sites occupied by forests but previously used as pastures. Forest and pasture age influenced δ13C values, resulting in different isotopic signatures for different sites, confirming the transition from C3 to C4 plants. In 50-year-old pastures, about 66 % of soil TOC is still derived from the primary forest biomass.

Investigation of Long-Term Forest Dynamics in Protected Areas of Northeast China Using Landsat Data

Forest dynamics, including forest loss and gain, are long-term complex ecological processes affected by nature and human activities. It is particularly important to understand the long-term forest dynamics of protected areas to evaluate their conservation efforts. This study adopted the Landsat tree-canopy cover (TCC) method to derive annual TCC data for the period 1984–2020 for the protected areas of northeast China, where protection policies have been carried out since the end of the 20th century, e.g., the Natural Forest Conversion Program (NFCP). A strong correlation was found between the TCC estimates derived from Landsat and LiDAR observations, suggesting the high accuracy of TCC. Forest loss and gain events were also identified from the time series of TCC estimates. High correlations were reported for both forest loss (Producer’s accuracy = 85.21%; User’s accuracy = 84.26%) and gain (Producer’s accuracy = 87.74%; User’s accuracy = 88.31%), suggesting that the approach can be used for monitoring and evaluating the effectiveness of the NFCP and other forest conservation efforts. The results revealed a fluctuating upward trend of the TCC of the protected area from 1986 to 2018. The increased area of TCC was much larger than the decreased area, accounting for 59.68% and 40.34%, respectively, suggesting the effectiveness of protection policies. Since the NFCP was officially implemented in 1998, deforestation was effectively curbed, the area of forest loss was significantly reduced (slope: −14.24%/year), and the area of forest gain significantly increased (slope: 4.13%/year). We found that regional forest changes were mainly manifested in “forest gain after loss (forest recovery)” and “forest gain with no loss (forest newborn)”, accounting for 40.29% and 37.28% of the total area of forest change, respectively. Moreover, the forest gain area far exceeds the forest loss area, reaching 11.24 million hectares, suggesting a successful forest recovery due to forest protection.

Severity of deforestation mediates biotic homogenisation in an island archipelago

Anthropogenic‐driven species extinctions are radically changing the biosphere. Biological communities may become increasingly similar to or dissimilar from one another via the processes of biotic homogenisation or heterogenisation. A key question is how the conversion of native forests to agriculture may influence these processes by driving changes in the occurrence patterns of restricted‐range endemic species versus wide‐ranging generalists. We examined biotic homogenisation and heterogenisation in bird communities on the Southeast Asian islands of Borneo, Sulawesi, Seram, Buru, Talaud and Sangihe. Each island is characterised by high levels of avian endemism and unique spatial configuration of forest conversion to agriculture. Forest conversion to agriculture influenced the patterns of biotic homogenisation on five islands. Bird communities became increasingly dissimilar to forest reference communities relative to localised patterns of deforestation. Turnover led to species with larger global range‐sizes dominating communities at the expense of island endemics and ecological specialists. Within islands, forest conversion did not result in clear changes to β‐diversity, whereas between‐island communities became increasingly similar with greater deforestation, implying that patterns of forest conversion profoundly affect biotic homogenisation. Our findings elucidate how continued conversion of forests is causing the replacement of endemic species by a small cohort of shared ubiquitous species with potentially strong negative consequences for ecosystem functioning and resilience. Halting reorganisation of the biosphere via the loss of range‐restricted species and spread of wide‐ranged generalists will require improved efforts to reduce the impacts of deforestation, particularly in regions with high endemism.

Stability of soil organic carbon pools affected by land use and land cover changes in forests of eastern Himalayan region, India

Forests are among the largest terrestrial carbon pools that are most vulnerable to land use and land cover change (LULC). Therefore, it is essential to manage forest ecosystems to enhance soil organic carbon (SOC) pools and soil functionality. The present study was carried out to analyze C stability and change in SOC stock under different forest types in the eastern Himalayan region of India. Topsoil (0–15 and 15–30 cm) samples from six dominant forests i. e. tropical wet evergreen, montane subtropical, temperate, Quercus, bamboo, and shifting cultivation (Jhum) lands were collected and analyzed for selected soil properties and SOC stock. Active (very labile + labile), slow (less labile), and passive (non-labile) C fractions were also analyzed to determine the stability of the SOC pool under the LULC scenario. Results show that the percentage contribution of active C to total organic carbon in topsoil was highest in a temperate forest (74.1%) while lowest in a bamboo forest (48.1%). Unlike, slow C (18.4%) and passive C (26.6%) were highest in Quercus forest. Pearson correlation analysis shows significant positive relation of active and slow C pool with SOC and total nitrogen concentration. The estimates of SOC stock (0–30 cm) were significantly higher in temperate forests (132.7 Mg C ha−1). However, the conversion of natural forests to bamboo forest and jhum land reduced SOC stock by 29% and 68%, respectively. C lability index shows higher labile C in jhum land while recalcitrancy index was highest in a bamboo forest. Our study concluded that LULC change significantly altered the stability and stock of SOC in natural forests. Owing to a higher percentage of slow and passive C pools, Quercus forests play a major role in C sink management.

Correlation of variations in species abundance of Atlantic forests regenerating on abandoned pastures with different environmental and spatial variables

The conversion of native forests into pastures is still a common practice in Brazil. Abandoned pastures have great potential for natural regeneration and therefore could play an important role in meeting the enormous demand for forest restoration. Few studies, however, have investigated the extent to which spatially-structured environmental variables and community structure are correlated with the variation in species abundance of regenerating forests on abandoned pastures. Therefore, we aimed to determine whether environmental and spatial variables were capable of explaining the variation in abundance of woody species on abandoned pastures in the subtropical Atlantic Forest. We systematically distributed 45 sample plots with size and inclusion criteria that changed according to the vegetation layer in three different abandoned pastures. In general, most of the variation in species abundance that our models were able to explain was correlated with spatially-unstructured physical-chemical soil properties. A smaller part of the variation was correlated with spatially-structured soil variables and topography-related variables. An even smaller portion of the variation was spatially-structured but was not correlated with spatially-structured environmental variables. Therefore, our results suggest that the variation in species abundance of regenerating subtropical Atlantic forests on abandoned pastures is more closely related to niche-based processes mediated by environmental variables than to stochastic spatial processes.

Do eucalypt plantations on Ferrosols in north-west Tasmania contain more or less soil carbon than native forests on the same soil type?

ABSTRACT Although studies in mainland states of Australia and overseas show that the conversion of native forests to plantations can reduce carbon (C) stocks in soils, no studies have been undertaken in Tasmania to assess how plantations affect soil C stocks. To address this knowledge gap, we compared soil C concentrations and C stocks to 30 cm depth in native ‘mixed’ eucalypt forests and adjacent Eucalyptus nitens plantations on Ferrosols in north-west Tasmania, using a factorial sampling strategy. Mean soil C and nitrogen (N) concentrations were significantly lower in plantations than in mixed forests; however, because the soils in plantations had higher bulk density, mean soil C stocks under the two treatments (114 Mg ha−1 and 116 Mg ha−1, respectively) were not significantly different. It is concluded that machine removal of 5–6 cm of topsoil into windrows during land clearing for plantations would be sufficient to explain why C concentrations were lower in plantations than in mixed forests and that, apart from this physical effect of land preparation, 17–21 years of plantation growth on Ferrosols in north-west Tasmania has not significantly affected soil C stocks in mineral soil. This result can be partly explained by the ability of Ferrosols to form stable complexes between organic matter, sesquioxides and clays.

Reduced litterfall and decomposition alters nutrient cycling following conversion of tropical natural forests to rubber plantations

Natural tropical landscapes have been continuously altered by land use change and other climate factors. Forest management practices have transformed massive tropical forests into rubber plantations throughout mainland Southeast Asia and Southwest China. However, the effect of the forest-to-plantation conversion on ecosystem functions associated with plant litter is limited. Here, we compare litterfall production, decomposition, nutrient return and nutrient use efficiency between a tropical natural forest (TNF) and a monoculture rubber plantation (MRP) in Xishuangbanna (China) over three years. Annual mean litterfall production was significantly higher in TNF (10.92 Mg ha−1 yr−1) than in MRP (5.23 Mg ha−1 yr−1). Production of leaf litter was positively correlated to that of total litterfall, suggesting that leaf litter could be reliably estimated from total litterfall. Temperature and solar radiation are dominant drivers of seasonal variation of litterfall production. The litterfall production was more sensitive to climate variables in MRP. The average stand litter and the decomposition quotient were 1.8 and 1.2 times greater in TNF than in MRP, respectively. The total nutrient return to the forest floor was 2.1 times higher in TNF (5.66 Mg ha−1 yr−1) than in MRP (2.76 Mg ha−1 yr−1); the return of each mineral element was significantly lower in MRP relative to TNF. The nutrient return preferentially occurred during the cold and dry seasons, which was consistent with the trend of litterfall. Relatively high N, P, Ca, and Mg use efficiencies were observed in MRP in line with their deficiency in the present tropical soils, indicating that rubber trees likely possess an efficient nutrient uptake mechanism to facilitate their adaption to oligotrophic habitats. Our results suggest that the large scale transformation of tropical forests to rubber plantations could alter the biogeochemical cycles related to litterfall, and thus possibly affect the resilience of ecosystems to climate variation. An increasing organic matter input in rubber monoculture may favor the sustainable development of rubber cultivation.

Changes in the composition of soil microbial communities and their carbon‐cycle genes following the conversion of primary broadleaf forests to plantations and secondary forests

AbstractThe soil organic carbon (C) cycle is primarily mediated by soil microorganisms and their genes that function in the C cycle (C‐cycle genes), both of which are strongly affected by land cover disturbance. However, the mechanism underlying microbially mediated soil C loss after conversion of primary natural broadleaf forests (BF) to plantation forests (PF) and secondary forests (SF) remains unknown. Here, we measured soil physicochemical properties and soil microbial community properties, and examined their linkages with microbial C‐cycle genes. Forest conversion dramatically decreased the richness of the soil fungal community but not of the bacterial community, and altered the composition of both communities. Analysis of C‐cycle genes revealed that the abundance of genes associated with C fixation, methane metabolism, and C degradation decreased by 51.3%, 57.9%, and 67.0%, respectively with the conversion of BF to PF; and by 6.3%, 4.1%, and 15.6%, respectively, with the conversion of BF to SF. The reductions in the abundance of C‐cycle genes, especially the reduction of hemicellulose‐ and lignin‐degradation genes, were primarily associated with the declines in the abundance of forest conversion‐sensitive microbes indexed by operational taxonomic units (fsOTUs, = 0.41). fsOTUs were taxonomically diverse and included members frequently co‐occurring with numerous other microbes in the microbial communities, indicating that the manipulation of fsOTUs by forest management could improve soil fertility and soil C sequestration. Forest conversion‐induced shifts in fsOTUs abundance were associated with changes in soil potassium permanganate oxidizable organic carbon (PXC) concentration, dissolved organic carbon (DOC) concentration, and soil pH. Our results indicate that alterations in soil substrate supply (e.g., DOC and PXC) and soil pH induced by forest conversion may strongly shape fsOTUs structure and decrease the abundance of hemicellulose and lignin degradation genes, and consequently increase C loss.

Effects of Pine Forest Management Practices on Bat Functional Traits in a Subtropical Region

Changes in landscape environmental characteristics may influence habitat use by bat species as well as species composition and community functional structure. Landscape features may drive the functional role variability of bat species on the ecosystems. Consequently, landscapes may change the degree of functional differentiation between species. We have evaluated the effect of pine forest monoculture and their environmental characteristics on the distribution and functional attributes of bat species. We sampled bat communities in areas with high (three sites) and low (three sites) forest land use management practices including six mist-netting locations in order to sample for bats at each site. In addition, we have also measured temperature, humidity, percentage of land use coverage (managed forest, agriculture, and native forest), and percentage of canopy openness at each site. We captured 87 bats belonging to eight species representing two families: Phyllostomidae and Vespertilionidae. For the functional analysis, we used three functional attributes to describe wing morphology: wing loading, aspect ratio, and forearm length. No significant effect of any environmental variable was observed on bat species composition. However, bat species distribution was driven by the ability associated with their functional attributes to occupy the space. Moreover, forearm length was positively correlated with forest cover, canopy openness, and humidity. Species with similar wing morphology have responded in a similar way to environmental variables in the studied areas. Functional dispersion was high in the native forest. The monoculture of exotic species may increase the functional attributes related with vulnerability as described by bat wing morphology. Therefore, the native forest conversion to pine forest monoculture may increase the loss of functional attributes in the bat community.

From forest to forestry: Reassembly of spider communities after native forest replacement by pine monocultures

Abstract Worldwide, natural ecosystems have been replaced by intensive productive systems. This has led to an extreme simplification of habitat structure and loss of ecosystem heterogeneity but also might reduce the opportunities for species co‐occurrence. Anthropogenic disturbances offer an opportunity to explore how the functional diversity of spiders within a highly diverse ecosystem such as a subtropical forest change under intensive productive systems such as monoculture tree plantations. It allows to study the mechanisms underlying the community re‐assemblage process. Using a set of morphological and ecological traits of 259 species, the habitat filtering hypothesis was tested on spider communities inhabiting pine monocultures at different ages, where the stabilisation of habitat conditions such as vegetation complexity, maximum temperature/relative humidity and prey availability along the plantation cycle growth will promote spider colonisation of these productive areas. The conversion of native forest to pine monocultures decreased species and trait richness of spiders. Moreover, spiders from both communities differed in their identity but exhibited similar functional traits (low trait replacement). Variation in trait composition of spiders was explained by changes in vertical stratification complexity, tree density and relative humidity, rather than prey availability. The mechanistic processes structuring the spider community were not clear. Spiders from pine plantations might experience frequent changes in composition due to high species replacement levels in space and time. Because pine plantations harbour only a few species and exhibit low functional richness, the pressure for stabilisation of community composition can be low.

The Effect of the Conversion from Natural Broadleaved Forests into Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) Plantations on Soil Microbial Communities and Nitrogen Functional Genes

The conversion of forests could change soil characteristics and, in turn, impact the microbial community. However, the long-term effect of forest transformation on bacterial and archaeal composition and diversity, especially on nitrogen functional communities, is poorly understood. This study aimed to explore the response of soil bacterial and archaeal communities, as well as nitrogen functional groups, to the conversion from natural broadleaved forests to Chinese fir (Cunninghamia lanceolate (Lamb.) Hook.) plantations in subtropical China by 16S rRNA amplicon sequencing. Except for soil bulk density (BD) and ammonium nitrogen (NH4+–N) content, other soil properties all decreased with the conversion from natural forests to plantations. Alpha diversity of bacteria and archaea declined with the transformation from natural forests to plantations. The composition of bacteria and archaea was significantly different between natural forests and plantations, which could be mainly attributed to the change in the content of soil organic carbon (SOC), total nitrogen (TN), nitrate nitrogen (NO3−–N), and available phosphorus (AP). The conversion of natural forests to plantations decreased the gene copies of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and nifH (nitrogen fixation function) but increased denitrification gene copies (i.e., nirS, nirK, and nosZ). In summary, our study emphasizes the long-term negative effect of the conversion from natural broadleaved forests into Chinese fir plantations on the diversity and richness of soil microbial communities, thereby deeply impacting the cycling of soil nitrogen.

Enhanced soil quality after forest conversion to vegetable cropland and tea plantations has contrasting effects on soil microbial structure and functions

Land-use changes could potentially exert a strong influence on soil quality and soil microbial communities. Moreover, microbial taxa are also important drivers of soil ecological functions. However, the linkage between soil quality and soil microbial communities is in need of deeper understanding. Here, we examined the effects of soil fertility quality on microbial community structure that identified by pyrosequencing and functions that predicted by the FAPROTAX functional annotations dataset after forest conversion to vegetable cropland and tea plantations. Soil quality index was significantly increased after natural forest (0.2) conversion to vegetable cropland (0.7) and tea plantations (0.3–0.6). Soil bacterial beta diversity significantly correlated to soil quality index, but the sensitivity of individual microbial groups varied in response to changes in soil quality. Higher soil quality promoted bacterial diversity in vegetable cropland but decreased it in tea plantations, which implied soil quality was a structural factor in bacterial community composition but had contrasting effects for croplands versus plantations. Agricultural management played a negative role in maintaining microbial interactions, as identified by the network analysis, and furthermore the analysis revealed key functions of the microbial communities. After land-use change, the abundance (e.g., level, intensity) of microbial groups involved in N-cycling increased in tea plantations but decreased in vegetable cropland. The abundance of microbes involved in C-cycling featured an opposite trend. Higher level of N-fixation in tea plantations but the higher abundance of N-oxidation in vegetable cropland was demonstrated. Higher abundance of ammonia-oxidizing bacteria (8.5 × 104 vs. 0.9–2.4 × 104 copies) and ammonia-oxidizing archaea (3.0 × 105 vs. 0.5–1.0 × 105 copies) as identified by qPCR in cropland than that in plantations corroborated the FAPROTAX prediction. Therefore, the key taxa of soil microbial communities and microbial functions were largely dependent on changes in soil quality and determined responses to specific agricultural management.

Soil microbial stoichiometry and community structure responses to long-term natural forest conversion to plantations in a subtropical region.

Soil microbial stoichiometry reflects carbon (C) and nutrient (e.g., nitrogen (N) and phosphorus (P)) elemental balances under land-use change (LUC). However, how soil microbial community (SMC) structure and stoichiometry respond to long-term LUC in forests is still unclear. Here, we investigated three 36-year-old typical plantations, Cryptomeria fortunei, Metasequoia glyptostroboides, and Cunninghamia lanceolata, and the natural forest to assess their soil microbial stoichiometry and SMC structure. Three plots (30×30 m2) were randomly set in each forest site. In each plot of every forest site, soil samples of three depths (0-10, 10-30, and 30-60 cm) were collected. Dissolved organic C, N, and P (abbreviated as DOC, DON, and DOP, respectively) and environmental factors were measured. We also detected microbial biomass C, N, and P as well as SMC structure. The results showed that the soil microbial C:N:P stoichiometry had a strong or strict homeostasis regardless of soil depth and exhibited decoupling from the SMC structure at each depth. The SMC structure across forest types was mainly driven by mean annual soil temperature (MAST) and DOC at 0-10 cm depth, by soil water content and MAST at 10-30 cm depth, and by DOC to DOP ratio at 30-60 cm depth. Thus, SMC structure could be jointly regulated by available resources and environment. These results suggest that the C dynamics in forests tend to gain resilience or re-equilibrium over more than three decades after forest conversion. These findings highlight the importance of reforested plantations forest management for sustaining soil C over a long term.

柑橘园扩张对生态系统服务和景观格局的影响——以江西省信丰县为例

PDF HTML阅读 XML下载 导出引用 引用提醒 柑橘园扩张对生态系统服务和景观格局的影响——以江西省信丰县为例 DOI: 10.5846/stxb202108152249 作者: 作者单位: 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（71873053）；国家社会科学基金重大项目（18ZDA054） Effects of citrus orchard expansion on ecosystem services and landscape pattern: A case study of Xinfeng County, Jiangxi Province, China Author: Affiliation: 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:柑橘园扩张是我国柑橘主产区较典型的土地利用/覆盖变化过程之一。但柑橘园扩张对区域生态系统服务和景观格局的影响尚不清楚，探明柑橘园种植的生态效应对柑橘主产区实现生态-经济协同发展具有重要的理论和现实意义。以江西省信丰县为研究区，基于第二次、第三次全国国土调查数据，借助InVEST模型、景观格局指数、图谱分析等方法，结合地形梯度和相关性分析，对柑橘园扩张所致的生态系统服务和景观格局变化及其权衡与关联进行分析。结果表明：①2010-2019年，柑橘园扩张方向以占用林地和耕地为主，柑橘园面积从9961.29 hm2增至12633.84 hm2，其中新增柑橘园7504.72 hm2，退出柑橘园4832.16 hm2，区域内柑橘园转换频繁。②柑橘园扩张导致信丰县景观格局总体呈现破碎化趋势，景观连通性降低，并对土壤保持服务和碳储量服务产生负向影响，对柑橘供给服务产生正向影响，对产水服务几乎无影响。③不同类型柑橘园在不同地形梯度上的扩张对生态系统服务的影响方向和程度存在差异。④在权衡与协同分析中，供给服务与支持服务呈权衡关系，碳储量-产水、碳储量-土壤保持等支持服务之间呈协同关系；景观破碎化与生态系统服务显著关联。研究结果可为经济作物大规模种植区的园地合理开发利用和生境保护提供科学依据。 Abstract:The conversion of natural forest and cultivated land to citrus orchard has become one of the typical land use/cover change processes in major citrus producing areas in China. Enlarging citrus cultivation can bring promising profitability to smallholders. However, the ecological consequences of enlarging citrus cultivation on ecosystem services (ES) and landscape patterns remain unclear. It is of great significance to explore the ecological effects of citrus orchard scale planting on the eco-economic synergistic development of major citrus producing areas. This paper focuses on analyzing the changes of ESs and landscape pattern, their correlation and the tradeoff/synergy of ESs change caused by citrus orchard expansion, using a case of Xinfeng County, Jiangxi Province. First, we used TUPU analysis methods to characterize the spatial and temporal variation of citrus orchard expansion from 2010 to 2019, based on the data of the secondly and thirdly national land survey. Second, InVEST model was employed to evaluate critical ES dynamics caused by citrus orchard expansion, and then we analyzed its differences in different terrain gradients. Third, we applied correlation analysis to examine the tradeoffs between ESs and the relationships between ESs and landscape patterns. The results showed that:(1) from 2010 to 2019, the expansion direction of citrus orchards was mainly converted from forest land and cultivated land, and the area of citrus orchards increased from 9961.29 hm2 to 12633.84 hm2, with 7504.72 hm2 newly transferred in and 4832.16 hm2 transferred out. The contradiction among forest land, cultivated land and citrus orchard is prominent in Xinfeng County. (2) The expansion of citrus orchards has boosted the supply of citrus supply services, whereas it had a negative impact on soil conservation services and carbon storage services. Soil conservation and carbon storage services decreased by 67.19% and 35.98%, respectively, from 2010 to 2019 throughout the region as a whole. Surprisingly, its impact on water yield services was not significant, with only a 5% reduction over the research period. Moreover, citrus orchard expansion has also resulted in a decrease in landscape connectivity and a trend of fragmentation in Xinfeng County. (3) The expansion of different citrus orchards on different terrain gradients had different effects on ESs. (4) In the tradeoff and synergy analysis, there was a tradeoff relationship between supply services and support services, and there was a synergy relationship between carbon storage-water yield and carbon storage-soil conservation. It is found that landscape fragmentation is significantly correlated with ESs. These results can provide scientific evidence for the rational development and utilization of gardens and habitat protection in large-scale cash crop planting areas. 参考文献 相似文献 引证文献

Forest Cover Change Detection using Geospatial Technologies in Chandaka National Park, Odisha, India

Forest plays a vital role in carbon sequestration and climate regulation. A crucial tool for managing forest, particularly in protected regions, is keeping track of how the land cover changes in natural places. Using geospatial approaches, such as remote sensing and geographic information system (GIS), the present study has revealed spatio-temporal changes in land use categories and forest cover in the Chandaka National Park of Odisha, India, throughout the period of 1980-2020. The Landsat, LISS III and Sentinel satellite images of the year 1980, 2000 and 2020 were utilized respectively to map five land use land cover categories i.e. deciduous broadleaf forest, crop land, mixed forest, scrub land and water bodies in this preserved area. The satellite images were classified using a Supervised Classification method using Maximum Likelihood algorithm and ground control points (GCPs) were used for the spatial statistical analyses. The overall accuracies of the classification method in land cover categories in year 1980, 2000 and 2020 were 90.45%, 92.76% and 94.68%, respectively. Elsewhere, in order to study land use land cover (LULC) change and loss in forest of the Chandaka National Park, LULC classification, per-pixel scales post classification and self-knowledge on the LULC change process were used. The LULC change detection results showed that deciduous broadleaf forest decreased from 179.01 sq. km (76.66%) in 1980 to 132.75 sq. km (56.85%) in 2020, while mixed forest cover increased by 8.17 sq. km (3.50%) in 1980 to 38.84 sq. km (16.63%) in 2020. Crop land, Scrub land and Water bodies were also increased by 3.34%, 3.27% and 0.07%, respectively. Two significant change processes in the area are the logging activities in several places for timber and the conversion of natural forests with plantation. Agriculture expansion in the forest’s periphery is linked to the dramatic decline in forest cover change. The decline in forest cover is also a result of the production of charcoal and lumber exploitation. Overall, our findings indicated that more public awareness and participatory forest management are necessary to preserve Chandaka National Park. This study highlights the use of geospatial technologies in understanding the changes in LULC in the Chandaka National Park.