Affinity among mountain ranges in Megamexico: A phytogeographical scenario

Resource Division in an Understory Herb Community: Responses to Temporal and Microtopographic Gradients

Marchalina hellenica (Gennadius) (Hemiptera: Margarodidae) is a scale insect, endemic in pine (Pinus halepensis) forests of Greece and other Mediterranean countries, which plays a major role in the production of honeydew honey. We investigated the morphological and the biological characteristics of M. hellenica in the pine forests of Mt. Parnis in comparison with those in the high-altitude fir (Abies cephalonica) forest of Mt. Helmos where it has been recently established, after anthropogenic intervention. Morphologically, the final body size of the 1st instar and the adult stages of M. hellenica in the fir forest were equal to those in the pine forest. Biologically, in the fir forest, the insect exhibited a long 1st instar’s period, which was the stage of its overwintering. In the pine forest, the 1st instar period was short and the insect overwinters in the stage of 2nd instar. The number of eggs per female in the fir forest was quite low (25–145) compared with the number of eggs in the pine forest (200–300). Concerning the qualitative parameters of the resulting honeydew-honey, statistically significant differences were found in Diastase and HMF (p < 0.0001). No difference was found in sucrose, fructose + glucose and water content, neither to electrical conductivity and total acidity. All values were within the EU limits (EU Directive 2001).

Pine forest and mixed forest in Mount Merbabu National Park (MMNP) have the different potential of macrofungi. However, the information of macrofungi in the pine and mixed forest is still lacking. The research aimed to determine the diversity and distribution of macrofungi in the pine forest and mixed forest MMNP. Retrieval of macrofungi diversity data used a plot method measuring 20 × 20 m which was divided into 16 subplots measuring 5 × 5 m. Subplots measuring 5 × 5 m was used to determine the distribution pattern of macrofungi. The results showed that there were 36 species of macrofungi found in the pine forest and 80 species in the mixed forest. The diversity of macrofungi in the pine forest belonged to moderate value with a diversity index of 2.84, whereas in the mixed forest belonged to high value with a diversity index of 3.64. There were 16 species macrofungi that can be found in the pine forest, 60 species that can be found in the mixed forest, and 20 species in both habitats. The most widespread macrofungi were the agaric type, which included Agaricales order, while the narrowest distributed macrofungi were the coral type, which include the Gomphales order. The distribution pattern of macrofungi species in the pine forest was obtained by 33 grouped species and three uniform species. The distribution pattern of macrofungi species in the mixed forest was obtained by 78 grouped species and two uniform species.

In the present study we evaluated how management practices, structural habitat parameters and arthropod availability affect bat activity, species richness and species diversity (estimated by Shannon's diversity index H') in a cultural landscape composed by a mosaic of different habitats in Brandenburg (Germany). Over a study period of two years (2012–2013), a standardised acoustic monitoring was conducted on 12 sampling sites comprising different land use types in forests (pine, mixed and deciduous forest) and agricultural areas (arable land and grassland). The focus was on the effect of small-scale changes in structural habitat parameters resulting from management practices within one-and-the-same land use type. We applied a paired sampling design and compared two (forest) and three (agricultural areas) sampling sites (complexity categories) per land use type. An effect of structural complexity was tested using parametric and non-parametric analyses. Sampling sites differ in a complexity index derived from vegetation measurements related to: a) vertical vegetation structure (pine forests), b) tree species composition (mixed forests), c) tree age (deciduous forests), d) crop type (arable land), and e) management intensity (grassland). Within the pine and mixed forest, management practices leading to an increase in structural habitat complexity were associated with a significant increase in bat activity, species richness, and species diversity (H'). This effect is only partially explained by increased prey abundance. On grassland, increased bat abundance is associated with low-intensity management practices. This effect is explainable by an increase in arthropod abundance associated with structural complexity but no additional effect of structural complexity beyond that. On arable land, the difference in structural complexity among different crops (and not prey abundance) significantly affects bat communities. Our approach employed proxy measures of habitat quality to estimate which management practices within the study area theoretically result in suitable and available habitats to meet the requirements of local bat species. Thus, our findings have implications for forest and agricultural management. Even minor changes in silvicultural management (understory development in pine monocultures and increased percentage of deciduous trees in mixed forests) may lead to a significant increase in forest habitat quality for bats. The findings also stress the importance of extensive management practices in grassland, as well as structure-rich crops on arable land to achieve a more environmentally sustainable farmland management.

The features of the distribution of fat-soluble organic compounds in the leaves of deciduous shrubs Rubus idaeus and Sorbus aucuparia growing in identical weather conditions in mixed and pine forests of the southern taiga of Western Siberia are shown. The composition of n-alkanes, saturated and unsaturated fatty acids, n-aldehydes, n-alkane-2-ones, n-alkanols, acyclic isoprenoids, steroids and pentacyclic triterpenoids was studied by chromatomass spectrometry. It was found that the microclimate of pine forest and mixed forest influences the composition of organic compounds in the leaves of single-species plants. In a mixed forest, among acyclic compounds, the total proportion of n-alkanes and the relative content of high-molecular homologues of n-alkanes, n-aldehydes and n-alkane-2-ones in rowan and raspberry leaves were increased. The composition of steroids is dominated by sitosterol, while in the bushes of mixed forest, unlike pine forest, there is a higher proportion of keto-substituted stigmast-4-en-3-one and the hydrocarbon stigmast-3,5-diene. Pine raspberries are distinguished by the presence of cholesterol, lanosterol and lanost-8-en-3-one, an increased content of cycloartenol. The leaves of ash among the pentacyclic triterpenoids identified a- and β-amerins, and the leaves of the raspberry a-, β- and d-amerins, among which in the pine forest increased the proportion a- amerin, and in the mixed forest – d-amerin. Raspberry leaves are dominated by neolup-12-en-3-ol, whereas in the leaves of mountain ash of mixed forest – lupeol, and pine forest – presumably 28-norneogop-18-en-3-ol. It is shown that the distribution of fat-soluble compounds depends not only on the type of plant, but also on the conditions of its growth, which must be taken into account when planning the practical use of plant raw materials.

Soil N transformations using the polyvinyl chloride (PVC) closed-top tube in situ incubation method were studied in Nanchang urban forests of the mid-subtropical region of China in different months of 2007. Four plots of 20 m × 20 m were established in four different plant communities that represented typical successional stages of forest development including shrubs, coniferous forest, mixed forest and broadleaved forest. Average concentrations of soil NH4+-N from January to December were not different among the four plant communities. The concentrations of soil NO3−-N and mineral N, and the annual rates of ammonification, nitrification and net N-mineralization under the early successional shrub community and coniferous forest were generally lower than that of the late successional mixed and broad-leaved forests (p<0.05). Similar differences among the plant communities were also shown in the relative nitrification index (NH4+-N/NO3−-N) and relative nitrification intensity (nitrification rate/net N-mineralization rate). The annual net N-mineralization rate was increased from younger to older plant communities, from 15.1 and 41.4 kg·ha−1·a−1 under the shrubs and coniferous forest communities to 98.0 and 112.9 kg·ha−1·a−1 under the mixed and broad-leaved forests, respectively. Moreover, the high annual nitrification rates (50–70 kg·ha−1·a−1) and its end product, NO3−-N (2.4–3.8 mg·kg−1), under older plant communities could increase the potential risk of N loss. Additionally, the temporal patterns of the different soil N variables mentioned above varied with different plant community due to the combined affects of natural biological processes associated with forest maturation and urbanization. Our results indicated that urban forests are moving towards a state of “N saturation” (extremely nitrification rate and NO3−-N content) as they mature.

The mixed Cunninghamia lanceolata (Lamb.) Hook., Pinus massoniana Lamb., and hardwood forest in southeastern China is a major assemblage in natural secondary forests, and of national and international importance in terms of both timber and ecosystem services. However, over-harvesting has threatened its long-term sustainability, and there is a knowledge gap relating to the effect of harvesting on the ecosystem. After conifer species were selected for harvesting, the mixed Chinese fir, pine, and hardwood forest was changed into mixed evergreen broadleaf forest. In this context, we observed the restoration dynamics of plant communities over a period of 15 years (1996 to 2011) with different levels of harvesting intensity, including selective harvesting at low (13.0% removal of growing stock volume), medium (29.1%), high (45.8%), and extra-high (67.1%) intensities, as well as clear-cut harvesting (100.0%), with non-harvesting as the control, based on permanent sample plots established in a randomized block design in these forests in southeastern China. The impact on the richness, diversity, and evenness of plant species derived from descriptive statistical analyses was shown to initially increase, and then decrease, with an increase in harvesting intensity. The most critical impacts were on the richness, diversity, and evenness of shrub and herb species. Richness, diversity, and evenness of plant species recovered and increased under selective harvesting at low and medium intensities, while these parameters had not recovered and significantly decreased under selective harvesting at high and extra-high intensities, as well as with clear-cut harvesting. The impact on the plant community stability was derived from the stability test method of the improved Godron M. The plant community stability was closest to the point of stability (20/80) under selective harvesting at medium intensity, followed by selective harvesting at low intensity. The plant community stability was far from the point of stability (20/80) under selective harvesting at high and extra-high intensities, as well as with clear-cut harvesting. Of these treatments, clear-cut harvesting had the greatest effect with regard to reducing stability. Therefore, these results indicate that the selective harvesting at low and medium intensities is conducive to preserve or increase the species diversity and community stability. In order to prioritize promoting plant species diversity, clear-cut harvesting and selective harvesting at high and extra-high intensities should be avoided with regard to this type of forest in this region. This study sheds light on the practice of forest operation in the study region and subtropical forests with the same environment.

In the process of subtropical forest succession, it has long been recognized that population decline of Masson pines in coniferous-broadleaf mixed forest is caused by shading from broadleaf trees. However, little is known about the mechanism underlying the interaction between them. Here, we first chose two sets of Masson pine plots approximately aged 60 years in subtropical mountainous areas in eastern China (i.e., pure coniferous forest vs. coniferous-broadleaf mixed forest). Then, we measured and compared tree height, diameter at breast height, first branch height (FBH), live crown ratio (LCR) of Masson pines between the two sets of plots, and also determined the difference in growth performance of Masson pines relative to their neighboring broadleaf trees in the mixed forest stand. Compared with plots in pine forests, Masson pines in mixed plots had lower tree height and crown breadth, higher FBH, lower LCR, and leaf area. Furthermore, the difference of mean FBH between reference trees (Masson pines) and their neighboring trees (i.e., broadleaf trees) in mixed forest plots was greater than that in pine forest plots, and the ratio of LCR between Masson pines and their neighbors (0.46) in mixed forest was significantly smaller than in pine forest (1.05), indicating that those broadleaf trees around Masson pines probably affected their growth. The mean distance between Masson pines and neighboring trees (1.59 m) in mixed forest plots was significantly shorter than in pine forest plots (2.77 m) (p &lt; 0.01), suggesting that strong competition may occur between reference trees and their neighbors. There was a significant difference in the ratio of crown volume between reference tree Masson pine and its neighboring trees in mixed forests (p &lt; 0.01), indicating that the ratio of biomass synthesis to consumption of pines was much lower than their nearby broadleaf trees in mixed forest. Our results have demonstrated for the first time that Masson pines’ population decline is affected by shade-tolerant broadleaf late-successional species, which can be primarily attributed to the distinctive light transmittance of dominant species nearby (pure pine vs. mixed forest). This study provides a new perspective for future studies on the mechanism of forest succession.

Chinese fir plantation is an important part of the subtropical forests in southern China. It has a sustainable natural regeneration ability, which is the foundation of determining community succession direction and maintaining their large area. The main objective of this study was to investigate whether the seed pool was the main restricting factor for the natural regeneration of Chinese fir plantation. Mixed broad leaf-conifer forest and pure plantation of Chinese fir were selected to study the species composition, quantity and seasonal dynamics of all species and dominant species. The results showed that seeds from 21 species belonged to 13 families and 18 genera were collected in the mixed forest, while seeds from 19 species belonged to 12 families and 16 genera were collected from pure forest. Seed rain intensities of all species were 3797 and 3300 seeds·m-2 in mixed forest and pure plantation, respectively. The number of seeds from tree species was absolutely dominant in seed rain (mixed forest 89.1%, pure plantation 86.2%). The number of Chinese fir seeds was the largest, the intact seeds intensities were 825 and 345 seeds·m-2, respectively. The proportion of all types of seeds in both stands followed the order: the intact seeds > empty or rotten seeds > feeding seeds. The seed rain of both stands had significant seasonal dynamics, both reaching the peak in autumn. The seed rain mainly was intact seeds at the peak of seed-falling. Both mixed forest and pure plantation of Chinese fir had plenty of seeds. The results indicated that the seed rain is not the main factor that restricts natural regeneration in Chinese fir plantations.

A phytosociological study of the juniper (locally called huito), pine (locally called sacch), pine-alder and fir forests of the Sierra de los Cuchumatanes and Cadena Volcanica in Guatemala was carried out. The Zurich-Montpellier approach was followed. In total 119 releves were sampled and the data were organised in phytosociological tables to distinguish vegetation clusters. TWINSPAN was used to evaluate major differences among plant communities. Seven zonal plant communities were distinguished and described, namely: (1)Relbunium microphyllum-Agrostis tolucensis, (2)Werneria nubigena-Agrostis exserta, (3)Lachemilla vulcanica-Pinus hartwegii, (4)Holodiscus argenteus-Pinus hartwegii, (5)Hypnum cypressiforme-Juniperus standleyi, (6)Agave hurteri-Alnus firmifolia and (7)Sabazia pinetorum-Abies guatemalensis. This paper provides a thorough floristic characterisation of each community and outlines the major anthropogenic activities. To conclude, ecologic and floristic (dis)similarities between plant communities of the study area and those of Central Mexico, like the different altitudinal distribution of fir forests and the establishment of mid-successional communities such as theAgave hurteri-Alnus firmifolia were discussed.

У результаті досліджень було встановлено, що формування кореневої системи21-річних насаджень обліпихи крушиноподібної в техноземах залежить від якості посадочного матеріалу і глибини його посадки в ґрунт; від потужності і якості відсип-ки древньоалювіальних відкладень і родючого шару ґрунту на поверхню шахтнихпорід, яка є нижньою межею корененаселеного шару рекультивованого едафотопу ітим самим обмежувачем зростання і розвитку рослин.

Diversity indices and relative abundances were determined for amphibians inhabiting three differently managed forest types in South Carolina. Study sites were contiguous around a small lake, and included a slash pine (Pinus ellioti) forest, a loblolly pine (Pinus taeda) forest and a hardwood (predominately oak-hickory) forest. Amphibians were collected using a drift fence and pitfall trap method. Captured animals were marked so that recaptures could be removed from calculations of indices. The dates of study were 30 June-10 August 1977 and 20 June-15 August 1978. The three study sites were similar in species diversity and the evenness component for combined summer data and for the summer of 1978. The hardwood forest had a higher diversity in the summer of 1977. The hardwood forest yielded approximately 50% more individual amphibians than either pine forest during both years.

Long-term monocultures of tea and the excessive use of chemical fertilizer lead to the degradation of soil quality. Improving the soil quality of ex-tea plantations through vegetation restoration is an important task. However, the changes in soil nutrients, fungal communities, and the effects of microorganisms on soil nutrients after reforestation remain unclear. Therefore, in this study, we aimed to explore the effects of Pinus and Chinese fir on soil nutrients and fungal communities in ex-tea plantation areas that were subjected to the reforestation modes of pure forest and mixed forest by measuring soil chemical properties and ITS rRNA gene sequences. The results showed that (1) after reforestation, the relative normalized difference vegetation index (NDVI) of the Mixed forest, Mixed Pine and Mixed Fir areas increased (p &lt; 0.05) compared to that of pure forest; (2) the soil organic carbon (SOC), total nitrogen (TN), and N:P ratios of the mixed forest increased by an average of 54%, 90%, and 299% (p &lt; 0.05) compared to pure forest, whereas the total phosphorus (TP) and available potassium (AK) decreased by an average of 39% and 89% (p &lt; 0.05); and (3) there was no significant difference in the diversity of the fungal communities of the pure and mixed forests, but the fungal phyla Mucoromycota, Glomeromycota, and Rozellomycota were significantly different in the pure and mixed forests. This differing microbial composition led to a significant increase (p &lt; 0.05) in symbiotrophs (ecotomycorhizal, ericoid mycorhizal) in the mixed forest, which was negatively correlated with the soil TP and positively correlated with the TN and the N:P ratio. In addition, there was also a significant decrease (p &lt; 0.05) in complex nutrient types (ectomycorrhizal-fungal parasite-plant saprotroph-wood saprotroph), which were negatively correlated with the SOC and TN, and arbuscular mycorrhizas, which were positively correlated with the TP. Our results show that the chemical properties of soils and the structure of the fungal communities changed significantly due to the reforestation of Chinese fir and Pinus, and the mixed forest mode of reforestation was more conducive to improving the soil quality; therefore, a mixed forest of Chinese fir and Pinus can be used to improve degraded soils in ex-tea planting areas.

Functional diversity of soil microbial communities under Scots pine, Norway spruce, silver birch and mixed boreal forests

The exchange of dimethyl sulfide (DMS), carbon disulfide (CS2), and dimethyl disulfide (DMDS) between soil and the atmosphere was investigated in three subtropical forests in south China, namely, a monsoon evergreen broadleaf forest (BF) in climax successional stage, a pine and broadleaf mixed forest (MF) in midsuccessional stage, and a pine forest (PF) in primary successional stage. The forest soils acted as sources for DMS with average flux in BF (1.27 ± 1.40 pmol m−2 s−1) significantly higher than those in MF (0.46 ± 0.30 pmol m−2 s−1) or in PF (0.47 ± 0.36 pmol m−2 s−1). Litter‐removed plots showed 55%, 21%, and 53% lower DMS emission fluxes compared to litter‐remained plots in BF, MF, and PF, respectively, suggesting the litter layer made evident contribution to DMS emission. DMS fluxes were significantly higher in rain seasons than in dry seasons. Dependence of DMS fluxes on soil temperature varied in the three forests, and significant correlations between DMS fluxes and soil temperature were only observed in BF and MF. No significant correlation was found between soil water content and DMS fluxes. However, DMS fluxes were found to be significantly correlated with soil temperature and water content together in polynomial forms with an order of 2. DMS fluxes were also exponentially correlated with CO2 fluxes. CS2 and DMDS fluxes showed no consistent direction. CS2 fluxes varied between −8.51 and 4.72 pmol m−2 s−1 and DMDS fluxes between −0.25 and 2.00 pmol m−2 s−1, respectively. No clear patterns were found for the influence of litter layer on the CS2 or DMDS fluxes.