Relative importance of climate, vegetation, and spatial factors in the community and functional composition of wood-inhabiting fungi in discontinuously distributed subalpine spruce forests

Wood-inhabiting fungi are critically important for the decomposition of coarse woody debris (CWD). To evaluate the relative importance of climate, vegetation, and spatial factors in the functional composition of fungal communities that inhabit CWD in discontinuously distributed subalpine Hondo spruce (Picea jezoensis (Sieb. & Zucc.) Carr. var. hondoensis (Mayr) Rehder) forests, a metabarcoding analysis was conducted on spruce deadwood samples obtained from six subalpine forests in central Japan using a high-throughput DNA sequencing technique. We detected 454 fungal operational taxonomic units (OTUs) from 67 spruce CWDs and determined that spatial factors explained a larger fraction of community variation than environmental (climate and vegetation) factors at all six study sites. However, environmental factors explained a larger fraction than spatial factors if we excluded data from one site that is geographically distant from other study sites. The OTU number and the occurrence of brown-rot fungi were positively associated with mean annual temperature and negatively associated with mean annual precipitation. Similarly, the principal component of forest vegetation significantly affected the OTU number and occurrence of brown-rot fungi. Precipitation seasonality was positively associated with the OTU number of undefined saprotrophs. These results suggest that fungal OTUs belonging to different functional groups respond differently to environmental variables.

Seasonal changes in the pigment composition of needles of representatives of the genus spruce in the Nizhny Novgorod region

Изучали характер и масштаб сезонных изменений пигментного состава хвои разных видов ели (Picea A. Dietr.) в условиях интродукции в Нижегородскую область, выявляли содержание и баланс пластидных пигментов фотосинтеза. Объектами исследования выступали 13 видов ели, относящихся к аборигенам и экзотам: ель европейская (Picea abies (L.) H. Karst.); ель сибирская (Picea obovata Ledeb.); ель Глена (Picea glehnii (F. Schmidt) Mast.); ель белая (Picea glauca (Moench) Voss); ель шероховатая (Picea asperata Masters); ель черная (Picea mariana Mill., Britton, Sterns & Poggenburg); ель колючая форма серебристая (Picea pungens Engelm., f. argentea); ель колючая форма голубая (Picea pungens Engelm., f. glauca Regel); ель сербская (Picea omorika (Pančić) Purk.); ель Энгельмана (Picea engelmannii Parry ex Engelm.); ель колючая (Picea pungens Engelm.); ель аянская (Picea jezoensis (Siebold & Zucc.) Carrière); ель корейская (Picea koraiensis Nakai). Отбор проб осуществлен рендомизированно с соблюдением принципа единственного логического различия. Использовали спектрофотометр СФ-2000. Установлено, что содержание и соотношение пластидных пигментов в хвое динамично в течение года. Определена эффективность влияния фаз сезонного развития растений на характеристики пигментного состава: по содержанию хлорофилла-a – 18,86±0,32%; по содержанию хлорофилла-b – 21,26±0,31%; по сумме хлорофиллов – 16,13±0,33%; по каротиноидам – 37,43±0,25%; по доле хлорофилла-a – 39,74±0,24% и доле хлорофилла-b – 39,74±0,24%. Эффект влияния межвидовых различий по показателям содержания и соотношения разных форм хлорофилла и каротиноидов достоверен и в достаточной мере выравнен при максимуме 23,56±0,91%. При общих тенденциях в сезонной динамике представители рода ель обладают заметной видоспецифичностью пигментного состава. We studied the nature and scale of seasonal changes in the pigment composition of needles of different spruce species (Picea A. Dietr.) under the conditions of introduction to the Nizhny Novgorod region, and revealed the content and balance of photosynthetic plastid pigments. The objects of the study were 13 species of spruce belonging to aborigines and exotics: Norway spruce (Picea abies (L.) H. Karst.); Siberian spruce (Picea obovata Ledeb.); Glen spruce (Picea glehnii (F. Schmidt) Mast.); white spruce (Picea glauca (Moench) Voss); Dragon spruce (Picea asperata Masters); black spruce (Picea mariana Mill., Britton, Sterns & Poggenburg); silver prickly spruce (Picea pungens Engelm., f. argentea); blue prickly spruce (Picea pungens Engelm., f. glauca Regel); Serbian spruce (Picea omorika (Pančić) Purk.); Engelman spruce (Picea engelmannii Parry ex Engelm.); Blue spruce (Picea pungens engelm.); Ayan spruce (Picea jezoensis (Siebold & Zucc.) carrière); Korean spruce (Picea koraiensis Nakai). Sampling was carried out in a randomized manner, following the principle of a single logical difference. A spectrophotometer SF-2000 was used. It was found that the content and ratio of plastid pigments in conifers is dynamic throughout the year. The effectiveness of the influence of the phases of seasonal plant development on the characteristics of the pigment composition is determined: by the content of chlorophyll-a-18.86±0.32%; by the content of chlorophyll-b-21.26±0.31%; by the sum of chlorophylls-16.13±0.33%; by carotenoids – 37.43±0.25%; by the proportion of chlorophyll-a – 39.74±0.24% and the proportion of chlorophyll-b – 39.74±0.24%. The effect of interspecific differences in the content and ratio of different forms of chlorophyll and carotenoids is significant and sufficiently equalized at a maximum of 23.56±0.91%. With General trends in seasonal dynamics, representatives of the spruce genus have a noticeable species-specific pigment composition.

Non-Structural Carbohydrate Storage Strategy Explains the Spatial Distribution of Treeline Species

Environmental factors that drive carbon storage are often used as an explanation for alpine treeline formation. However, different tree species respond differently to environmental changes, which challenges our understanding of treeline formation and shifts. Therefore, we selected Picea jezoensis and Betula ermanii, the two treeline species naturally occurring in Changbai Mountain in China, and measured the concentration of non-structural carbohydrates (NSC), soluble sugars and starch in one-year-old leaves, shoots, stems and fine roots at different elevations. We found that compared with P. jezoensis, the NSC and soluble sugars concentrations of leaves and shoots of B. ermanii were higher than those of P. jezoensis, while the starch concentration of all the tissues were lower. Moreover, the concentration of NSC, soluble sugars and starch in the leaves of B. ermanii decreased with elevation. In addition, the starch concentration of B. ermanii shoots, stems and fine roots remained at a high level regardless of whether the soluble sugars concentration decreased. Whereas the concentrations of soluble sugars and starch in one-year-old leaves, shoots and stems of P. jezoensis responded similarly changes with elevation. These findings demonstrate that compared with P. jezoensis, B. ermanii has a higher soluble sugars/starch ratio, and its shoots, stems and fine roots actively store NSC to adapt to the harsh environment, which is one of the reasons that B. ermanii can be distributed at higher altitudes.

Climate influences the effect of fungal decay type on regeneration of Picea jezoensis var. hondoensis seedlings on decaying logs

Hondo spruce (Picea jezoensis var. hondoensis (Mayr) Rehder)) is separately distributed among several mountainous regions in central Japan as remnant populations of the last glacial period. To identify factors that affect Hondo spruce seedling regeneration on decaying logs, we investigated the relationships between climatic conditions, log properties, including decay type by fungi, and Hondo spruce seedling density on logs using data from seven subalpine Hondo spruce forests in central Japan. The results showed that the presence of soft rot was associated with higher seedling density, and the effect of brown rot in sapwood and white rot in heartwood on the predicted number of spruce seedlings on logs switched from positive to negative with increasing temperature and precipitation. Because soft rot occurs under humid conditions, the use of forest management techniques that increase the number of logs with soft rot in sapwood (e.g., by keeping the forest floor moist) are recommended for the sustainable regeneration of Hondo spruce. However, the relationships between wood decay type and seedling regeneration can also be affected by climate condition and thus are more complex than previously thought.

Reconstruction of June–July Temperatures Based on a 233 Year Tree-Ring of Picea jezoensis var. microsperma

In this study, ring-width chronology of Picea jezoensis var. microsperma from the Changbai Mountain (CBM) area, Northeast China, was constructed. Growth/climate responses suggested that mean maximum temperature (Tmax) was the limiting factor affecting radial growth of PJ trees in the study region. According to the correlation analysis between the ring-width index and meteorological data, a June–July mean maximum temperature (Tmax6–7) series between 1772 and 2004 was reconstructed by using the standard chronology. For the calibration period (1959–2004), the explained variance of the reconstruction was 41.6%. During the last 233 years, there were 36 warm years and 34 cold years, accounting for 15.5% and 14.7% of the total reconstruction years, respectively. Cold periods occurred in 1899–1913, 1955–1970, and 1975–1989, while warm periods occurred in 1881–1888. The reconstructed temperature series corresponded to the historical disaster records of extreme climatic events (e.g., drought and flood disasters) in this area. Comparisons with other temperature reconstructions from surrounding areas and spatial correlation analysis between the gridded temperature data and reconstruction series indicated that the regional climatic variations were well captured by the reconstruction. In addition, multi-taper method spectral analysis indicated the existence of significant periodicities in the reconstructed series. The significant spatial correlations between the reconstructed temperature series and the El Niño–Southern Oscillation (ENSO), solar activity, and Pacific Decadal Oscillation (PDO) suggested that the temperature in the CBM area indicated both local-regional climate signals and global-scale climate changes.