Composition and spatio-temporal dynamics of aquatic bird community in humid areas of Alto Parana Atlantic Forest / Composição e dinâmica espaço-temporal da comunidade de aves aquáticas em áreas úmidas da Floresta Atlântica do Alto Paraná

Abstract The northwestern portion of the Upper Paraná Atlantic Forest ecoregion is one of the most disturbed and fragmented areas in the Atlantic Forest, and little is known about the local avifauna. In this study, we have described the composition and diversity of the aquatic avifauna of this region and analyzed the patterns of similarity with respect to the seasonal as well as spatial distribution. We used the line transect sampling technique in six distinct humid areas (including lentic and lotic water bodies) during the dry and rainy seasons of 2012 and 2013. A total of 52 species of waterfowl were recorded. The species richness of the studied areas was surprisingly distinct; only seven waterfowl species, namely Cairina moschata (Linnaeus, 1758), Tigrisoma lineatum (Boddaert, 1783), Rosthramus sociabilis (Vieillot, 1817), Aramus guarauna (Linnaeus, 1766), Vanellus chilensis (Molina, 1782), Jacana jacana (Linnaeus, 1766), and Arundinicola leucocephala (Linnaeus, 1764), were common to these six studied areas. This indicated that the other bird species that were observed might be habitat selective. Moreover, the analysis of the composition of birds in the two seasons (dry and rainy) combined with their spatial distributions showed significant dissimilarities between the areas with lotic (river and constructed wetland) and lentic (lagoons) characteristics. Nevertheless, despite the small extent and low total richness of the entire study area, it was found to be home to 1/3 of all freshwater aquatic birds documented in the state of São Paulo, with the record of 5 migratory species and 11 new species added to the northwest of the state. The heterogeneity of local aquatic environments, habitat selection combined with seasonality, and the absence of other humid locations in the surroundings can explain the diversity and distribution of these birds in the water bodies of this uninvestigated Atlantic Forest ecoregion.

Resumo A porção noroeste da ecorregião Floresta Atlântica do Alto Paraná é uma das mais alteradas e fragmentadas da Mata Atlântica, da qual pouco se sabe sobre a avifauna local. Nosso objetivo foi descrever a diversidade e composição da avifauna aquática, bem como analisar os padrões de similaridade quanto a distribuição temporal e espacial destas aves nesta ecorregião. Utilizamos a transecção linear para amostragem em seis áreas úmidas (corpos d'água lênticos e lóticos), nos períodos de seca e chuva entre 2012 e 2013. Registramos 52 espécies de aves aquáticas e as riquezas das áreas mostraram-se distintas, pois apenas Cairina moschata (Linnaeus, 1758), Tigrisoma lineatum (Boddaert, 1783), Rosthramus sociabilis (Vieillot, 1817), Aramus guarauna (Linnaeus, 1766), Vanellus chilensis (Molina, 1782), Jacana jacana (Linnaeus, 1766), and Arundinicola leucocephala (Linnaeus, 1764) foram comuns às seis áreas, o que indica seleção de habitat. Quando analisada a composição das aves nos dois períodos aliada à distribuição espacial, encontramos dissimilaridades temporais acentuadas entre os ambientes com características lóticas (rio e aterro) e lênticas (lagoas). Isto mostra que, além das diferentes épocas sazonais, é necessário analisar separadamente os diferentes tipos de áreas úmidas. Por fim, apesar da extensão pequena e baixa riqueza total, a área amostrada abrigou 1/3 das aves aquáticas de água doce para o estado de São Paulo, cinco espécies migratórias e 11 novas espécies para o noroeste do estado. A heterogeneidade de ambientes aquáticos locais, forte seleção de habitat aliada à sazonalidade e ausência de outros locais úmidos em seu entorno, explicam a diversidade e distribuição destas aves estreitamente relacionadas aos corpos d'água desta desconhecida ecorregião da Mata Atlântica.

Riverine forest as a significant habitat to harbor a wide range of bird species / Floresta ribeirinha como hábitat significativo para abrigo de uma gama de espécies de aves

Riverine forests are unique and highly significant ecosystems that are globally important for diverse and threatened avian species. Apart from being a cradle of life, it also serves as a gene pool that harbors a variety of flora and fauna species (repeated below). Despite the fact, this fragile ecosystem harbored avian assemblages; it is now disappearing daily as a result of human activity. Determining habitat productivity using bird species is critical for conservation and better management in the future. Multiple surveys were conducted over a 15-month period, from January to March 2019, using the distance sampling point count method. A total of 250 point count stations were fixed systematically at 300 m intervals. In total, 9929 bird individuals were recorded, representing 57 species and 34 families. Out of 57 bird species, two were vulnerable, one was data deficient, one was nearly threatened, and the remaining 53 species were of least concern. The Eurasian Collard Dove - Streptopelia decaocto (14.641 ± 2.532/ha), White-eared Bulbul - Pycnonotus leucotis (13.398 ± 4.342/ha) and Common Babbler - Turdoides caudata (10.244 ± 2.345/ha) were the three first plenteous species having higher densities. However, the densities of three species, i.e., Lesser Whitethroat - Sylvia curruca, Gray Heron - Ardea cinerea and Pallas Fish Eagle - Haliaeetus leucoryphus, were not analyzed due to the small sample size. The findings of diversity indices revealed that riverine forest has harbored the diverse avian species that are uniformly dispersed across the forest. Moreover, recording the ten foraging guilds indicated that riverine forest is rich in food resources. In addition, the floristic structure importance value index results indicated that riverine forest is diverse and rich in flora, i.e. trees, shrubs, weeds and grass, making it an attractive and productive habitat for bird species.

As florestas ribeirinhas são ecossistemas únicos e altamente significativos que são globalmente importantes para diversas espécies de aves ameaçadas de extinção. Além de serem o berço da vida, também servem como um conjunto genético que abriga uma variedade de espécies da flora e da fauna. Apesar disso, esse frágil ecossistema abrigava um conjunto de aves, mas agora está desaparecendo diariamente como resultado da atividade humana. Determinar a produtividade do hábitat usando espécies de pássaros é fundamental para a conservação e melhor gestão no futuro. Vários levantamentos foram realizados ao longo de um período de 15 meses, de janeiro de 2018 a março de 2019, por meio do método de contagem de pontos de amostragem de distância. Foram fixadas sistematicamente 250 estações de contagem de pontos em intervalos de 300 m. No total, foram registrados 9.929 indivíduos de aves, representando 57 espécies e 34 famílias. Das 57 espécies de aves, duas eram vulneráveis, uma tinha dados insuficientes, uma estava quase ameaçada e as 53 espécies restantes eram as menos preocupantes. O: Pomba de colar euroasiática - Streptopelia decaocto (14.641 ± 2.532/ha), o Bulbul de orelha branca - Pycnonotus leucotis (13.398 ± 4.342/ha) e Tagarela comum - Turdoides caudata (10.244 ± 2.345/ha) foram as três primeiras espécies abundantes com maiores densidades. No entanto, as densidades de três espécies, Papa-amoras-cinzento (Sylvia curruca), Garça-real-europeia (Ardea cinerea) e Águia-pescadora de Pallas (Haliaeetus leucoryphus), não foram analisadas por causa do pequeno tamanho da amostra. Os resultados dos índices de diversidade revelaram que a floresta ribeirinha abrigou diversas espécies de aves que estão uniformemente dispersas pela floresta. Além disso, o registro das dez guildas de forrageamento indicou que a floresta ribeirinha é rica em recursos alimentares. Além disso, os resultados do índice de valor de importância da estrutura florística indicaram que a floresta ribeirinha é variada e rica em flora, ou seja, árvores, arbustos, ervas daninhas e grama, tornando-a um hábitat atraente e produtivo para espécies de aves.

Variations in soil physico-chemical properties, soil stocks, and soil stoichiometry under different soil layers, the major forest region Liupan Mountains of Northwest China / Variações nas propriedades físico-químicas do solo, estoques e estequiometria do solo sob diferentes camadas de solo, a principal região florestal das montanhas Liupan do noroeste da China

Liupan Mountains are an important region in China in the context of forest cover and vegetation due to huge afforestation and plantation practices, which brought changes in soil physio-chemical properties, soil stocks, and soil stoichiometries are rarely been understood. The study aims to explore the distribution of soil nutrients at 1-m soil depth in the plantation forest region. The soil samples at five depth increments (0-20, 20-40, 40-60, 60-80, and 80-100 cm) were collected and analyzed for different soil physio-chemical characteristics. The results showed a significant variation in soil bulk density (BD), soil porosity, pH, cation exchange capacity (CEC), and electric conductivity (EC) values. More soil BD (1.41 g cm-3) and pH (6.97) were noticed in the deep soil layer (80-100 cm), while the highest values of porosity (60.6%), EC (0.09 mS cm-1), and CEC (32.9 c mol kg-1) were reflected in the uppermost soil layer (0-20 cm). Similarly, the highest contents of soil organic carbon (SOC), total phosphorus (TP), available phosphorus (AP), total nitrogen (TN), and available potassium (AK) were calculated in the surface soil layer (0-20 cm). With increasing soil depth increment a decreasing trend in the SOC and other nutrient concentration were found, whereas the soil total potassium (TK) produced a negative correlation with soil layer depth. The entire results produced the distribution of SOCs and TNs (stocks) at various soil depths in forestland patterns were 0→20cm > 20→40cm > 40→60cm ≥ 60→80cm ≥ 80→100 cm. Furthermore, the stoichiometric ratios of C, N, and P, the C/P, and N/P ratios showed maximum values (66.49 and 5.46) in 0-20 cm and lowest values (23.78 and 1.91) in 80-100 cm soil layer depth. Though the C/N ratio was statistically similar across the whole soil profile (0-100 cm). These results highlighted that the soil depth increments might largely be attributed to fluctuations in soil physio-chemical properties, soil stocks, and soil stoichiometries. Further study is needed to draw more conclusions on nutrient dynamics, soil stocks, and soil stoichiometry in these forests.

As montanhas de Liupan são uma região importante na China no contexto de cobertura florestal e vegetação devido às enormes práticas de florestamento e plantação, que trouxeram mudanças nas propriedades físico-químicas do solo, e estoques e estequiometrias do solo raramente são compreendidos. O estudo visa explorar a distribuição de nutrientes do solo a 1 m de profundidade do solo na região da floresta plantada. As amostras de solo em cinco incrementos de profundidade (0-20, 20-40, 40-60, 60-80 e 80-100 cm) foram coletadas e analisadas para diferentes características físico-químicas do solo. Os resultados mostraram uma variação significativa nos valores de densidade do solo (BD), porosidade do solo, pH, capacidade de troca catiônica (CEC) e condutividade elétrica (CE). Mais DB do solo (1,41 g cm-3) e pH (6,97) do solo foram observados na camada profunda do solo (80-100 cm), enquanto os maiores valores de porosidade (60,6%), CE (0,09 mS cm-1) e CEC (32,9 c mol kg-1) foram refletidos na camada superior do solo (0-20 cm). Da mesma forma, os maiores teores de carbono orgânico do solo (SOC), fósforo total (TP), fósforo disponível (AP), nitrogênio total (TN) e potássio disponível (AK) foram calculados na camada superficial do solo (0-20 cm). Com o aumento do incremento da profundidade do solo, uma tendência decrescente no SOC e na concentração de outros nutrientes foi encontrada, enquanto o potássio total do solo (TK) produziu uma correlação negativa com a profundidade da camada do solo. Todos os resultados produziram a distribuição de SOCs e TNs (estoques) em várias profundidades de solo em padrões de floresta 0 → 20cm> 20 → 40cm> 40 → 60cm ≥ 60 → 80cm ≥ 80 → 100 cm. Além disso, as relações estequiométricas de C, N e P, as relações C / P e N / P, apresentaram valores máximos (66,49 e 5,46) em 0-20 cm, e valores mais baixos (23,78 e 1,91) em solo de 80-100 cm profundidade da camada. Embora a relação C / N fosse estatisticamente semelhante em todo o perfil do solo (0-100 cm). Esses resultados destacaram que os incrementos de profundidade do solo podem ser amplamente atribuídos a flutuações nas propriedades físico-químicas do solo, estoques e estequiometrias do solo. Mais estudos são necessários para tirar conclusões adicionais sobre a dinâmica dos nutrientes, estoques de solo e estequiometria do solo nessas florestas.

Ethnomedicinal uses of plants for various diseases in the remote areas of Changa Manga Forest, Pakistan / Usos etnomedicinais de plantas para várias doenças nas áreas remotas da Floresta Changa Manga, Paquistão

This study aims at reporting the indigenous knowledge of the medicinal flora from the inhabitants of surroundings of the World's largest artificial planted forest "Changa Manga", Pakistan. Data were collected by direct interviews and group meetings from 81 inhabitants including 32 local healers having information regarding the use of indigenous medicinal plants over a period of one year. Different statistical tools were applied to analyze the data including Frequency citation (FC), Relative frequency citation (RFC), Use Value, Factor of informants consensus and fidelity level. This study reported 73 plant species belonging to 37 plant families and 46 genera. The majority of plant species belong to compositae family. The most commonly used medicinal plants were P. hysterophorus L., P. dactylifera L., S. indicum L, P. harmala L., P. emblica L., and A. indica A.Juss. The greatest number of species was used to cure gastrointestinal disorders. The highest fidelity level (68.18%) was of E. helioscopia to cure gastrointestinal disorders. Maximum fresh uses (17) were reported by C. dactylon (L.) Pars. While the highest number of species reporting fresh uses in similar number was 13. In this study, five novel plants are being reported for the first time in Pakistan for their ethnomedicinal worth. Our data reflect unique usage of the medicinal plants in the study area. The statistical tools used in the study proved useful in pointing the most important and disease category specific plants. High use value plant and the new reported medicinal plants might prove an important source of the isolation of pharmacologically active compounds.

Este estudo tem como objetivo relatar o conhecimento indígena sobre a flora medicinal dos habitantes do entorno da maior floresta artificial plantada do mundo, a Changa Manga, no Paquistão. Os dados foram coletados por meio de entrevistas diretas e reuniões em grupo de 81 habitantes, incluindo 32 curandeiros locais, com informações sobre o uso de plantas medicinais indígenas durante o período de um ano. Diferentes ferramentas estatísticas foram aplicadas para analisar os dados, incluindo citação de frequência (FC), citação de frequência relativa (RFC), valor de uso, fator de consenso dos informantes e nível de fidelidade. Este estudo relatou 73 espécies de plantas pertencentes a 37 famílias de plantas e 46 gêneros. A maioria das espécies de plantas pertence à família Compositae. As plantas medicinais mais utilizadas foram P. hysterophorus L., P. dactylifera L., S. indicum L., P. harmala L., P. emblica L. e A. indica A. Juss. O maior número de espécies foi usado para curar distúrbios gastrointestinais. O maior nível de fidelidade (68,18%) foi de E. helioscopia para cura de distúrbios gastrointestinais. Os usos máximos em fresco (17) foram relatados por C. dactylon (L.) Pars. enquanto o maior número de espécies relatando usos frescos em número semelhante foi de 13. Neste estudo, cinco novas plantas estão sendo relatadas pela primeira vez no Paquistão por seu valor etnomedicinal. Nossos dados refletem o uso exclusivo das plantas medicinais na área de estudo. As ferramentas estatísticas utilizadas no estudo mostraram-se úteis para apontar as plantas mais importantes e específicas da categoria de doença. Plantas de alto valor de uso e as novas plantas medicinais relatadas podem ser uma importante fonte de isolamento de compostos farmacologicamente ativos.

Tree species composition, growing stock and biomass carbon dynamics of the major timber species in Hindu Kush regions of Pakistan / Composição de espécies de árvores, estoque em crescimento e dinâmica de biomassa de carbono das principais espécies madeireiras nas regiões de Indocuche no Paquistão

Using inventory data, this study evaluates the species composition, growing stock volume (GSV), and biomass carbon (BMC) of the five major timber species in the sub-tropical, and temperate/sub-alpine regions of Pakistan. It was found that the stem density varies between 50 and 221 trees ha -1, with a mean of 142 trees ha-1 (13.68 million trees for entire forest area). Among the species, Pinus wallichiana showed a high species composition (27.80%) followed by Picea smithiana (24.64%). The GSV was found in the range of 67.81 to 425.94 m3 ha-1, with a total GSV value of 20.68 million m3 for the entire region. Similarly, The BMC ranged from 27.04 to 169.86 Mg ha-1, with a mean BMC value of 86.80 Mg ha-1. The total amount of stored carbon was found at 8.69 million tons for a total of 95842 ha of commercially managed forest. Furthermore, the correlation analysis between the basal area (BA) and GSV and BMC showed that BA is the best predictor of GSV and BMC. The findings provide insights to the policy makers and forest managers regarding the sustainable commercial forest management as well as forest carbon management in the recent global carbon management for climate change mitigation.

Usando dados de inventário, este estudo avaliou a composição de espécies, volume de estoque crescente (GSV) e carbono de biomassa (BMC) das cinco principais espécies madeireiras nas regiões subtropicais e temperadas/subalpinas do Paquistão. Constatou-se que a densidade do caule variou entre 50 e 221 árvores ha-1, com média de 142 árvores ha-1 (13,68 milhões de árvores para toda a área florestal). Entre as espécies, Pinus wallichiana apresentou alta composição de espécies (27,80%), seguida de Picea smithiana (24,64%). O GSV foi encontrado na faixa de 67,81 a 425,94 m3 ha-1, com um valor total de 20,68 milhões de m3 para toda a região. Da mesma forma, o BMC variou de 27,04 a 169,86 mg ha-1, com valor médio de 86,80 mg ha-1. A quantidade total de carbono armazenado foi de 8,69 milhões de toneladas para um total de 95.842 ha de floresta manejada comercialmente. Além disso, a análise de correlação entre área basal (BA), GSV e BMC mostrou que BA é o melhor preditor de GSV e BMC. As descobertas fornecem insights para os formuladores de políticas e gestores florestais sobre o manejo florestal comercial sustentável, bem como o manejo florestal de carbono no recente gerenciamento global de carbono para a mitigação das mudanças climáticas.

Land use and land cover changes and their impact on ecosystem service values in the north-eastern highlands of Ethiopia.

The land use and land cover (LULC) changes driven by the growing demands of mankind have a considerable effect on ecosystem services and functions. The study was carried out in the north-eastern highlands of Ethiopia to (1) analyze the effect of LULC changes between 1984 and 2021 and (2) assess the spatiotemporal variations in ecosystem service values (ESVs) and elasticity in response to LULC changes. Using Landsat imageries from 1984 to 2021, the spatiotemporal changes in LULC were evaluated with supervised image classification using maximum likelihood algorithm in ArcGIS software. Six LULC types were subsequently categorized, with overall accuracy and Kappa coefficients above 87% and 0.87, respectively. The ESVs were then estimated based on the Benefit Value Transfer (BVT) approach employing modified conservative value coefficients. The findings revealed a significant increase in cultivated land (9759.1ha) and built-up area (10174.41ha) during the stipulated periods and a drop in other land use types. The forest loss gradually decreased from 4.1% in the second period (1991-2001) to 0.58% in the third (2001-2021), compared to the first of the 1.1% conversion rates. Similarly, the proportion of grassland and water bodies steadily reduced over the stipulated periods, by 1.15% and 2.3% per annum, respectively. The overall loss of ESVs in the study landscape was estimated to be 54.4 million US$ (67.3%), drastically decreasing from 80.3 million US$ in 1984 to 26.4 million US$ in 2021, driven by the declining area coverage of water bodies, grassland, and forestland. Regardless of the loss, the ecosystem functions of hydrological regulation (37.2, 35.0, 6.1, and 5.1 US$ ha-1yr-1), water supply (14.5, 13.6, 2.4, and 2 US$ ha-1yr-1), and food production (9.8, 10.0, 9.1, and 9.9 US$ ha-1yr-1) contributed the most to the total ESV of each year while disturbance regulation and cultural values were the least throughout the study periods. The coefficient of sensitivity (CS) analysis revealed that our estimates were relatively robust. The findings further showed that human-dominated land-uses at the expense of natural ecosystems are the primary drivers of LULC transitions and the ensuing loss of ecosystem services in the region. Thus, this calls for intensive work on more effective land use policies that encourage an integrated management approach, with a focus on safeguarding the sustainability of natural ecosystems.

Spatial distribution pattern and correlation of dominant species in the arbor layer at a 25 hm2 forest plot in Lushan Mountain, China.

To explore the spatial pattern of zonal tree species in the subtropical subalpine mountain area on Lushan Mountain, a 25 hm2 forest plot was established in Yangtianping area of Lushan Mountain following the technical specification of CTFS in 2021. We classified these species into evergreen conifer species, deciduous broad-leaved species and evergreen broad-leaved species based on their leaf shape and deciduous or not to analyze the spatial pattern of dominant species of different types by spatial point pattern method. The results showed that Pinus taiwanensis, Cornus kousa subsp. chinensis, Platycarya strobilacea, Castanea henryi, Quercus serrata, Cornus controversa, Eurya muricata, Litsea elongata, and Eurya hebeclados were dominant species. Among these species, P. taiwanensis was the constructive one. The spatial pattern of dominant species was clustered at a certain scale, and gradually became to randomly distribution with the increases of scales. Evergreen conifer species was independent with deci-duous broad-leaved species and evergreen broad-leaved species at small scales, but was negatively correlated with them at large scales. Deciduous broad-leaved species and evergreen broad-leaved species were obviously negatively correlated with each other. Deciduous broad-leaved species were positively correlated or independent with each other at small scales, but were negatively correlated with each other at large scales. Evergreen broad-leaved species were positively correlated at small scales, independent at medium scales, and negatively correlated with each other at large scales.

Responses of root-associated fungal community structure of mycorrhizal plants to nitrogen and/or phosphorus addition in a subtropical forest.

Root-associated fungi play a vital role in maintaining nutrient absorption and health of host plants. To compare the responses of root-associated fungal community structures to nitrogen (N) and/or phosphorus (P) additions across differential mycorrhizal types, we collected roots of nine plant species belonging to three mycorrhizal types (arbuscular mycorrhiza, ectomycorrhiza, and ericoid mycorrhiza) under control and N and/or P addition treatments from a subtropical forest, and detected the diversity and community composition of fungi inhabiting roots through the high-throughput sequencing technique. The results showed that root-associated fungal communities of all nine plant species were mainly composed of Basidiomycota and Ascomycota. The relative abundance of Ascomycota and Basidiomycota was significantly lower and higher under the P addition than that under control, respectively. The relative abundance of Ascomycota of ericoid mycorrhizal trees was significantly higher than those of arbuscular mycorrhizal and ectomycorrhizal trees, while the relative abundance of Basidiomycota was significantly lower than the other two mycorrhizal types. Compared with the control, P addition significantly reduced the α-diversity and changed community composition of root-associated fungi across different mycorrhizal plant types, while no effect of N addition or mycorrhizal type was observed. Compared with the control and N addition treatments, NP addition caused root-associated fungal communities of all plants becoming integrally divergent. In addition, the fungal communities of ectomycorrhizal mycorrhizal trees became apparently convergent in comparison with those of arbuscular and ericoid mycorrhizal trees under the NP addition. Collectively, our results highlighted that P was a critical factor influencing community structures of tree root-associated fungi in subtropical forest soils. This study would enhance our understanding of the responses and maintenance mechanisms of plant root-associated fungal diversity under global environmental changes in the subtropical region.

Niche and interspecific association of dominant tree species in karst forest of Junzi Mountain, Eastern Yunnan, China.

To understand the interspecific relationships of tree species in the karst forest of Junzi Mountain in Eas-tern Yunnan, we evaluated the niche and interspecific association of dominant tree species based on field survey plot data with the combining approaches of niche determination, χ2 test, association coefficient (AC), and Spearman rank correlation test. The results showed that the niche breadth of Quercus glaucoides was the largest and that of Juglans mandshurica was the smallest. The ranking of niche breadth was more consistent with the ranking of frequency than with that of importance values. The degree of niche overlap was generally low, with a mean value of 0.21, suggesting a low similarity in resource utilization among tree species. The overall association of dominant tree species was significantly positive, and the ratio of positive and negative association was 1.07, indicating that the communities were at a relatively stable and the late succession stage. The χ2 test and Spearman rank correlation test for tree dominant species showed that 65.3% species pairs were not significantly associated with each other, indicating a weak interspecific association. Both association coefficient (AC) and Spearman rank correlation coefficient showed significantly positive correlations with the corresponding niche overlap index. The species pairs of Q. glaucoides-Rhamnella martini, Viburnum propinquum-Zanthoxylum myriacanthum, Cladrastis delavayi-Carrierea calycina, Z. myriacanthum-C. delavayi had strong interspecific associations and wide ecological niches, thus may have potential application value in ecological restoration of karst region in eastern Yunnan and the vicinity areas.

Differences in ecological resilience of radial growth between Larix principis-rupprechtii and Picea meyeri after drought.

To understand the responses of radial growth to climatic factors and the differences in ecological resilience to drought between a heliophilous species Larix principis-rupprechtii and a shade species Picea meyeri in mixed forests, we developed the tree-ring width chronologies of L. principis-rupprechtii and P. meyeri in three mixed forests based on the samples collected from Toudaogou of Saihanba in Hebei, Ningwu County and Kelan County in Shanxi Province. We analyzed the correlation between climatic factors and various chronologies and examined the differences in resistance (Rc), recovery (Rt), and resilience (Rs) of L. principis-rupprechtii and P. meyeri in response to drought stress. The results showed that the radial growth of L. principis-rupprechtii and P. meyeri was negatively correlated with the mean and maximum air temperature from May to July in three mixed forests, and was positively correlated with the Palmer drought index (PDSI) from May to September. Radial growth decline in trees due to drought stress was significantly different between the two species among the three sites, indicating different physiological and ecological regulation strategies. The resistance of P. meyeri was stronger than that of L. principis-rupprechtii at the three study sites, with stronger resilience and resilient elasticity of L. principis-rupprechtii than P. meyeri. As a result, P. meyeri exhibited greater drought resistance than L. principis-rupprechtii. Under global warming condition, L. principis-rupprechtii might be at greater risk of growth decline than P. meyeri in this region.

Three-dimensional model construction and wind simulation of different tree species in farmland shelter.

Protective forests are the ecological barriers of oases in arid sand areas and can effectively prevent and control wind and sand hazards. The structural characteristics of individual trees, as the basic unit of protective forests, are the key factors affecting the protective benefits. With the typical leafless tree species of Ulan Buh Desert oasis, i.e., Populus alba var. pyramidalis, Populus nigra var. thevestina, and Populus popularis, as the research objects, and by using the ground-based LiDAR and through computational fluid dynamics (CFD), we fully explored the structural characteristics of individual trees and their surrounding aerodynamic characteristics on the basis of real 3D models. We further established the relationship between structural parameters of individual trees and wind field index. The results showed that combining AdQSM and MeshLab to build tree models had high accuracy. The wind field around the individual trees could be roughly divided into six regions, including the attenuation zone of the windward side of the plant, the acceleration zone at the top of the plant, the eddy zone, the calm zone, the transition zone, and the recovery zone of leeward side of the plant. The pressure field around individual trees showed a gradual change of high pressure on the windward side to low pressure on the leeward side. Horizontally, in the range of 20% to 50% reduction in relative wind speed, the effective protection distances were 0.21H-1.51H, 0.20H-0.91H, and 0.25H-1.64H (H was the corresponding tree height) for P. alba var. pyramidalis, P. nigra var. thevestina, and P. popularis, corresponding to effective protection areas of 18-294, 15-227, and 18-261 m2, respectively. The maximum wind speed decay rate in the vertical direction was at 0.3H height for P. alba var. pyramidalis and P. popularis, and was reflected at 0.5H height for P. nigra var. thevestina. The correlation and stepwise regression analysis of the single tree structure parameters with the wind field indicators clearly indicated that optical porosity and volume porosity dominated the protection effect. Among the wind field factors, the best regression models related to the porous coefficient were screened for three factors, including diameter at breast height, tree surface area, and optical porosity. The regression variables screened for effective protection distance and effective protection area differed among the classes.

Effects of warming on fine root lifespan of forests: A review.

As an important parameter of forests growth, fine root lifespan plays an important role in plant water and nutrient absorption, and affects underground distribution of photosynthetic products and forest ecosystem carbon cycling. The impact of climate warming on fine root lifespan has become a hot issue under the context of global change. The responses of fine root lifespan to global warming will affect ecosystem carbon balance. We reviewed the research progress of the response characteristics and mechanism of fine root lifespan of trees to warming. Most stu-dies proposed that warming would affect fine root lifespan by changing rhizosphere soil environment, fine root morphology, and tree phenology. However, the growth and death of fine roots were affected by lots of factors, leading to differences in the research results on fine root lifespan due to natural environment of the study area, the way of warming, and the research objects. Therefore, it is of importance to comprehensively analyze the responses of fine root lifespan in forests under the background of climate warming to study the underground ecological process. In the future, the following research should be strengthened: 1) Combining multiple methods to warming underground and aboveground simutaneously, and explore more accurate and effective non-destructive observation methods. 2) Combining multiple observations to study the effects of warming on fine root lifespan. 3) Carrying out research on the effect of warming on fine root lifespan of different tree species, and deeply understand the response mechanism of fine root lifespan of different trees to warming. 4) A comprehensive analysis of the effects of warming on fine root lifespan from various perspectives, and an investigation into the mechanism of the combined effects of various factors on fine root lifespan. 5) The interaction between warming and other environmental factors fine root lifespan. 6) The effect of root architecture on the fine root lifespan after warming. 7) The effects of rhizosphere microorganisms (bacteria and fungi) on fine root lifespan after warming.

Applying the COM-B behaviour change model to a pilot study delivering volatile pyrethroid spatial repellents and insecticide-treated clothing to forest-exposed populations in Mondulkiri Province, Cambodia.

BACKGROUND: Southeast Asia is making tremendous progress towards their 2030 malaria elimination goal but needs new interventions to stop forest malaria. This study trials two new vector control tools, a volatile pyrethroid spatial repellent (VPSR) and insecticide-treated clothing (ITC), amongst forest-exposed populations in Mondulkiri Province Cambodia to inform their potential use for eliminating forest malaria. METHODS: 21 forest-exposed individuals were given a questionnaire on their perceptions of malaria and preventive practices used, after which they trialed two products sequentially. Clothes was treated with ITC by the study team. Mixed methods were used to understand their experience, attitudes, and preferences regarding the products trialed. Quantitative data was summarized and qualitative insights were analysed using thematic analysis, applying the Capability, Opportunity, and Motivation Behaviour Change (COM-B) model and Behaviour Change Wheel Framework to identify intervention functions to support tailored product rollout amongst these populations. RESULTS: Study participants reported a need for protection from mosquito bites in outdoor and forest-exposed settings and perceived both products trialed to be effective for this purpose. The VPSR product was preferred when travel was not required, whereas ITC was preferred for ease of use when going to the forest, especially in rainy conditions. COM-B analysis identified that key enablers for use of both products included their perceived efficacy and ease of use, which required no skill or preparation. For barriers to use, the odour of ITC was sometimes perceived as being toxic, as well as its inability to protect uncovered skin from mosquito bites, while the perceived usefulness of the VPSR product trialed was limited by its water sensitivity in rainy forest settings. Intervention components to encourage appropriate and sustained use of these products include education about how to use these products and what to expect, persuasion to use them from community leaders and targeted channels, and enablement to facilitate convenient and affordable access. CONCLUSION: The rollout of VPSRs and ITC amongst forest-exposed populations can be useful for eliminating malaria in Southeast Asia. Study findings can be applied to increase product uptake among forest exposed populations in Cambodia, while manufacturers can aim to develop products that are rainproof, easy to use in forest settings, and have favourable odour profiles to target users.

Effects of target tree management on understory regeneration in Pinus massoniana plantations.

To clarify the effects of target tree management on natural forest regeneration, with Pinus massoniana plantations in the low mountainous regions of eastern Sichuan with target tree densities of 100, 150 and 200 trees·hm-2 as test object, we analyzed the effects of management densities on canopy structure, plant diversity, and soil physicochemical properties on understory regeneration. The results showed that the regeneration index increased with management density, which increased 0.08-0.10 in the managed plantations compared with unmanaged sites. When the density of the target trees was 150 trees·hm-2, an increase of 9 regeneration tree species and an increase of 800 trees·hm-2 in quantity were observed. The dominance of herbaceous species was not prominent, but canopy structure was improved, and the regeneration ability of understory plants was enhanced. The impact of habitat factors on the regeneration index ranked as soil total porosity (0.591) > leaf area index (-0.536) > Shannon index (-0.085) > available P (0.053) > total N (-0.007) > Pielou index (-0.005). Target tree management facilitated understory regeneration in the P. massoniana plantations by improving soil pore conditions, reducing leaf area index, and decreasing herbaceous plant diversity index. A management density of 150 trees·hm-2 was more sui-table for target tree management in P. massoniana plantations.

Relationship between net primary productivity and stand age in typical plantation forests in China.

Plantation forests play an important role in carbon sink in terrestrial ecosystems. Based on tree rings of five main plantation tree species (Robinia pseudoacacia, Quercus variabilis, Cunninghamia lanceolata, Pinus sylvestris var. mongolica, and Pinus tabuliformis) at 25 sites in China, we calculated the average annual NPP of standard trees in each study area by the biomass equations and extended to the stand scale. The relationships between NPP and stand age were fitted by the InTEC and Law models. The results showed that NPP of R. pseu-doacacia, C. lanceolata, and P. tabuliformis plantations increased to a peak and then leveling off with stand age, while that of Q. variabilis and P. sylvestris var. mongolica plantations reached a peak and then showed a decreasing trend. The inflection points of NPP-stand age curve for different planatations was 11 years for P. sylvestris var. mongolica, 14 years for C. lanceolata, 16 years for P. tabuliformis, and 20 years for R. pseudoacacia. The NPP peak was 6.65, 7.58, 4.70 and 2.59 t·hm-2·a-1, respectively. Both the InTEC and Law NPP-stand age models had high fitting accuracy at a large scale, with the lowest R2 of 0.95 and RMSE of 0.55 t·hm-2·a-1 for the P. sylvestris var. mongolica InTEC model and the highest R2 of 0.99 and RMSE of 0.26 t·hm-2·a-1 for the C. lanceolata InTEC model. The construction of NPP-stand age relationship for major plantations in China provided mechanistic support for the estimation of carbon sinks in plantations at long time scales and provided a reference for the diversification of afforestation tree species selection.

Constraints on the maintenance of wild Taxus cuspidata populations based on regression conservation.

To clarify the key factors constraining the maintenance of wild Taxus cuspidata populations and to develop conservation strategies and technical links for current populations, we investigated the renewal status and distribution patterns of wild T. cuspidata populations in the main distribution areas of China. We analyzed the effects of stand factors and human disturbance on population renewal and maintenance. The results showed that the overall regeneration of wild T. cuspidata populations was poor. The basal diameter and height class structure of renewed individuals showed an unhealthy state. 19% of the area was well regenerated. There were three types of regeneration, including poor regeneration with few adult trees, poor regeneration with many adult trees, and good regeneration with few adult trees. The communities in which T. cuspidata was found could be classified into Abies nephrolepis + Tilia amurensis forest, spinney forest, and Picea jezoensis var. microsperma + A. nephrolepis forest. The renewal number of A. nephrolepis + T. amurensis forest was significantly higher than that of spinney forest. Increased stand density and moderate human disturbance contributed to the regeneration of T. cuspidata. The regenerating T. cuspidata seedlings increased significantly when stand density increased from low to medium. The number of regenerating populations in moderately disturbed habitats was significantly higher than those in lightly disturbed habitats. Human disturbance and habitat were currently critical constraints to maintaining and regenerating wild T. cuspidata populations. The conservation of T. cuspidata should consider current status of population regeneration in each habitat patch to develop corresponding in situ conservation and regression conservation measures and focus on the influence of critical factors such as disturbances and habitat conditions.

Understory fuel loads and the impact factors of Quercus mongolica natural secondary forest in Hebei Pro-vince, China.

We investigated understory fuel loads of Quercus mongolica natural secondary forests in Hebei Province, China. We analyzed the effects of stand factors, topographic factors, and ground cover factors on the quantity and composition of fuel, established the dynamic models of understory fuel loads, and proposed management measures. The results showed that the understory total fuel load in Q. mongolica natural secondary forests was 11.68 t·hm-2, which exceeded the forest fire potential threshold (10 t·hm-2). The understory dead fuel load was mainly humus, and the understory living fuel load was mainly shrubs. The 1 h time-lag fuel load increased significantly with increasing canopy density, stand density, stand age, and litter thickness. The 10 h time-lag fuel load increased signi-ficantly with increasing stand density, average tree height, and litter thickness. Humus load decreased significantly with increasing altitude and increased significantly with increasing humus thickness. Herb load increased significantly with increasing sunny slope orientation and herbal coverage. Shrub load increased significantly with increasing slope degree, shrub coverage, and humus thickness. Understory total fuel load decreased significantly with increasing altitude, and increased significantly with increasing stand density, humus thickness, and litter thickness. The results of stepwise regression analysis indicated that stand density, humus thickness, and altitude could better predict the understory total fuel load (Radj2=0.775). Therefore, more attention should be paid on the control of stand density of Q. mongolica natural secondary forest in Hebei Province. Cleaning of litters and humus on the ground would help prevent forest fires scientifically and effectively.

Instantaneous sap flow velocity simulation of Euonymus bungeanus based on neural network optimization model.

The sap flow of trees is complex and difficult to express with multivariate linear or empirical models. A simple and feasible method on the basis of understanding sap flow variation to simulate its variation with environmental factors is of special importance for quantitatively analyzing forest ecohydrological processes and regional water demand. In this study, with one of the shelter forest species Euonymus bungeanus in the east sandy land of Yellow River in Ningxia as the research object, we continuously measured the trunk sap flow velocity by thermal diffusion sap flow meter, and analyzed the effects of environmental factors on stem sap flow. We used the particle swarm optimization (PSO) and sparrow search algorithm (SSA) optimized neural network model to predict sap flow velocity of E. bungeanus. Results showed that the main environmental factors influencing sap flow were solar radiation, vapor pressure deficit, air temperature, and relative humidity, with the influencing importance of 32.5%, 25.3%, 22.0% and 16.1%, respectively. The response process between sap flow and environmental factors presented a hysteresis loop relationship. The optimized BP, Elman and ELM neural network models improved the comprehensive evaluation index (GPI) by 1.5%, 30.0% and 5.3%, respectively. Compared with the PSO-Elman and SSA-ELM optimization models, the SSA-BP optimization model had the best prediction results with an improvement of 1.0% and 23.2% in GPI, respectively. Therefore, the prediction results of the BP neural network model based on the sparrow search algorithm could be used as an optimal model for predicting instantaneous sap flow velocity of E. bungeanus.

Comparison of species composition and community characteristics of Quercus forests on south and north slopes of Taibai Mountain, China.

We examined species composition, community characteristics, diversity, and community similarity of five Quercus communities composed of three Quercus species (Q. variabilis, Q. aliena var. acutiserrata, Q. wutaishanica) on the altitudinal gradient on the south and north slopes of Taibai Mountain. The results showed that there was an altitudinal transition pattern from Q. variabilis pure forest to Q. variabilis-Q. aliena var. acutiserrata mixed forest, Q. aliena var. acutiserrata pure forest, Q. aliena var. acutiserrata-Q. wutaishanica mixed forest and Q. wutaishanica pure forest on the south and north slopes of Taibai Mountain. The main companion species of Quercus community on the north slope were Pinus armandii, Castanea seguinii, and Sorbus alnifolia, and were Pinus tabuliformis, C. seguinii, Carpinus cordata, and Q. spinosa on the south slope. Species richness, woody plant density, and Quercus species dominance on the north slope of Taibai Mountain were higher than those on the south slope. α diversity of tree layer in Quercus community on the south and north slopes of Taibai Mountain increased first, then decreased and then increased with altitude. α diversity of tree layer was higher in mixed forests than pure forests. α diversity of shrub layer was higher than that of tree layer and herb layer in Quercus community on south and north slopes. ß diversity fluctuated greatly along the altitudinal gradient on the south and north slopes, indicating that species composition changed greatly with altitude. Results of redundancy analysis showed that mean warmest month temperature, altitude and tree height accounted for 79.0% of the community diversity on the north slope, and that soil water content, tree height, canopy density and mean annual temperature accounted for 79.6% of the community diversity on the south slope. Overall, Quercus dominance was higher on the north slope of Taibai Mountain, and the substitution distribution pattern of Quercus species was clearer than that on the south slope. Environmental factors related to temperature and precipitation jointly affected α diversity of Quercus communities.

Relationship between carbon stock and the structure of coniferous and broad-leaved mixed forest in Tianmu Mountains, China.

Taking the coniferous and broad-leaved mixed forest of Tianmu Mountain National Nature Reserve in Zhejiang Province as research object, we divided the tree species into three pairs, including evergreen and deci-duous species, broad-leaved and coniferous species, dominant and non-dominant species, to compare the difference of the individual tree carbon stock of each pair and analyze the diameter distribution pattern and tree height distribution pattern of carbon stocks. The relationship between spatial structure and individual tree carbon stock was analyzed by using spatial structure indicators including V_Hegyi competition index, complete mingling and aggregation index, to reveal the relationship between the structure of coniferous and broad-leaved forests and carbon stocks, and provide a theoretical basis for management of forest carbon sequestration. The results showed that the average individual carbon stock for evergreen and deciduous species, broad-leaved and coniferous species, dominant and non-dominant species were 57.7 and 87.4 kg, 54.6 and 74.7 kg, 67.4 and 48.1 kg, respectively. The individual tree carbon stock of evergreen species was significantly lower than that of deciduous species, the individual tree carbon stock of broad-leaved species was significantly lower than that of coniferous species, and the individual tree carbon stock of dominant tree species was significantly higher than that of non-dominant tree species. The diameter distribution and height distribution of carbon stock of each species group obeyed normal distribution. The V_Hegyi competition index was significantly negatively correlated with individual tree carbon stock, and it was consistent with the power function distribution. Both complete mingling and aggregation index were linearly and positively correlated with individual tree carbon stock. The direction of influence of different spatial structures on the individual tree carbon stock was consistent. The structure of coniferous and broad-leaved mixed forest had a significant impact on individual tree carbon stock. In the management of forest carbon sequestration and sink enhancement, it is necessary to regulate the unreasonable forest structure and promote its succession to the climax community in order to improve forest carbon stock.