Plant litter is not only the major source of carbon (C) and nutrients for heterotrophic organisms in forest headwater streams, but also an important component of stream C storage. The dynamics of stream litter storage (i.e., the standing stock) are thus closely related to forest C fluxes, but has not been well assessed in the literature. To fill this gap, we investigated the monthly dynamics of plant litter storages at 17 reaches of a subtropical headwater stream from stream source to mouth during the rainy season (from March to August) of 2021. We found that (1), across sampling reaches, the mean litter storages of leaves, twigs (< 1 cm in diameter), fine woody debris (FWD, < 10 cm in diameter), reproductive parts (flowers and/or fruits), and barks in the stream during the rainy season were 25.6, 11.9, 16.7, 0.3, and 0.6 g/m², respectively, and the storage peak of total litter was in May, while the storage peaks at most of the sampling reaches were in April and May; (2) litter storage, especially leaf litter, at the stream source reach (i.e., reach 1) was significantly higher than those in the other reaches, and riparian forest type affected the storages of twig and FWD litter, with higher values in reaches with broad-leaved than mixed riparian forests; and (3) stream physicochemical characteristics, especially channel gradient, channel width, and water discharge and alkalinity, had significant effects on litter storage, but their effects varied among different litter types. Overall, our study clearly assessed the dynamics of plant litter storages in a headwater stream of subtropical forests, which will help us to better understand the role of headwater streams in forest carbon storage and cycling.

An elevation gradient affects temperature, precipitation, soil properties, and other environmental factors important for plant growth, resulting in differential responses of plant functional traits within and between species. Here, three transect lines were established along an elevation gradient of 1500 to 2900 m that spanned four vegetation types: desert grassland, low mountain shrub zone, subalpine coniferous forest, and subalpine shrub zone in a semiarid mountain ecosystem (western part of the Helan Mountains, Northwest China). Nine functional plant traits — leaf nitrogen (LN), leaf carbon (LC), leaf thickness (LT), specific leaf area (SLA), leaf phosphorus, leaf dry matter content, and the leaf carbon/leaf nitrogen (C/N), leaf carbon/leaf phosphorus (C/P), leaf nitrogen/leaf phosphorus (N/P) — were quantified to investigate (1) how the community-weighted means (CWM) and unweighted means (CM) vary; (2) how inter- and intraspecific functional traits vary; and (3) how the climate, topography and soil properties affect plant functional traits at the community level. We found that with rising elevation, SLA and LT increased and then decreased, while C/P and N/P showed opposite trend for both CWM and CM. Additionally, the higher LN and lower C/N were found in subalpine shrub zone. The leaf functional traits between CWM and CM showed no significant difference but a close relationship between them. Generally, all the leaf traits were explained better by interspecific variation than by intraspecific variation, except for N/P. The covariance analysis indicated that LP and LC showed negative covariance effects, whereas all other leaf traits showed positive covariance effects. The contribution to plant leaf traits from altitude was slightly higher than vapor pressure and soil organic carbon. Our major finding emphasize that plant communities in the western Helan Mountains were assembled along elevation primarily via interspecific variation.

In this study, the diversity of endophytic and epiphytic fungi communities was evaluated and compared from healthy, symptomless and green leaves of the medicinal plant Ziziphus lotus (wild jujube) growing in Northern Algeria. Culture-based methods were used to isolate the endophytes and epiphytes. Morphological and molecular analyses were applied for identification of the fungi taxa. Both communities of the phylloplane of Ziziphus lotus differed in size and composition. Out of all 52 species, 19 were identified as epiphytic fungi and 45 as endophytes with 12 species shared by the two communities (Aspergillus costaricaensis, A. tubingensis, Aureobasidium sp., Cladosporium asperlatum, C. halotolerans, C. limoniforme, Penicillium chrysogenum, P. desertorum, P. flavigenum, P. momoii, Stemphylium sp. and Trichothecium crotonigenum). The two communities were found to be moderately similar (Sørensen similarity index = 0.37). Higher diversity values were found in endophytic community compared to epiphytic community: Shannon's diversity index H' (3.29 vs 1.83), Simpson diversity index C' (0.94 vs 0.74), species richness (3.06 vs 0.46) and species evenness (0.86 vs 0.62). Additionally, the correlation matrix was generated for the identification of possible interactions between different fungi.

Hybridization, the interbreeding of individuals from different taxa, is usually the result of contact between closely related species. It occurs when reproductive barriers between species are not fully developed during speciation. Gulls are a classic example of hybridization in birds. However, the group of so-called “small gulls” is poorly recognized in this context. Here, we summarised data on Mediterranean gulls Ichthyeatus melanocephalus hybridization documented in Poland for the 2006–2022 period. In the mid-20th century, this species began successfully colonising many European countries, and the first documented breeding pair of Mediterranean gull was recorded in Poland in 1981. The first documented cross-breeding between a male Mediterranean gull and a female black-headed gull Chroicocephalus ridibundus was recorded in Poland in 2006. Since then, a total of 25 interspecific pairs, between Mediterranean gulls and black-headed gull or common gull Larus canus, have been observed. Interspecific pairs with black-headed gull were the most numerous (76%). However, mixed pairs – formed by one of parental species and individual of the Mediterranean gull hybrid – were the most common pair category (N = 60). Neither pairs consisting of two hybrids individuals nor of Mediterranean gulls × common gull hybrids have been recorded in the colonies. The number of Mediterranean gulls fluctuated between 50 and 100 pairs during studied period. The number of interspecific breeding pairs remained constant over a 17-year period, one to three pairs per breeding season, while the number of mixed breeding pairs has increased over time and reached maximum 9 pairs per season. Overall, there is a clear increase in the proportion of mixed and interspecific broods in relation to the number of pairs consisting of two ‘pure’ Mediterranean gulls, such pairs approached 38% in 2019.