Climate warming impacts chewing Spodoptera litura negatively but sucking Corythucha marmorata positively on native Solidago canadensis.

Insect-plant interactions are among importantly ecological processes, and rapid environmental changes such as temperature and resource fluctuations can disrupt long-standing insect-plant interactions. While individual impacts of climate warming, atmospheric nitrogen (N) deposition, and plant provenance on insect-plant interactions are well studied, their joint effects on insect-plant interactions are less explored in ecologically realistic settings. To this end, we performed five experiments with native and invasive Solidago canadensis populations from home and introduced ranges and two insect herbivores (leaf-chewing Spodoptera litura and sap-sucking Corythucha marmorata) in the context of climate warming and N deposition. We determined leaf defensive traits, feeding preference, and insect growth and development, and quantified the possible associations among climate change, host-plant traits, and insect performance with structural equation modeling. First, native S. canadensis populations experienced higher damage by S. litura but lower damage by C. marmorata than invasive S. canadensis populations in the ambient environment. Second, warming decreased the leaf consumption, growth, and survival of S. litura on native S. canadensis populations, but did not affect these traits on invasive S. canadensis populations; warming increased the number of C. marmorata on native S. canadensis populations via direct facilitation, but decreased that on invasive S. canadensis populations via indirect suppression. Third, N addition enhanced the survival of S. litura on native S. canadensis populations, and its feeding preference and leaf consumption on invasive S. canadensis populations. Finally, warming plus N addition exhibited non-additive effects on insect-plant interactions. Based on these results, we tentatively conclude that climate warming could have contrasting effects on insect-plant interactions depending on host-plant provenance and that the effects of atmospheric N deposition on insects might be relatively weak compared to climate warming. Future studies should focus on the molecular mechanisms underlying these different patterns.

Effects of fertilizer application on the growth of Stranvaesia davidiana D. seedlings.

Wild plants represent a potential source of urban landscape trees. Stranvaesia davidiana Dcne. is a member of the Stranvaesia Lindl. Genus, which belongs to family Rosaceae Juss. It has great ornamental value. It can contribute to urban color foliage and fruit species. However, the most effective fertilizer application strategy required for its cultivation is unknown. Therefore, we conducted an orthogonal experiment to investigate the fertilizer type and level (pure nitrogen) using ten experimental groups, including an untreated control group. Pot experiments were used to determine the growth indices of seedlings, including plant height, basal diameter, and chlorophyll content post-fertilizer treatment. This study explored the most appropriate fertiler application model for the growth of S. davidiana seedlings. The results revealed that enhanced seedling growth depended on the type and amount of fertilizer used, and their interaction. Fertilizer application increased the plant height by 2.67 cm to 12.26 cm, basal diameter by 0.39 cm to 0.75 cm, and chlorophyll content by 5.66 to 19.86. Among the different types of fertilizer, organic fertilizer increased the plant height by 0.42 cm to 9.59 cm and basal diameter by 0.01 cm to 0.05 cm, compared with the control group. Organic fertilizer had the maximum effect on seedling growth, especially at medium levels. The total growth of basal diameter and chlorophyll content was 1.58 ± 0.04 cm and 39.53 ± 2.37, respectively. Basal diameter is the most critical index in seedling reproduction . The study results suggest that the application of 4.06 g of organic fertilizer per plant was the most effective, and served as a basis for further field trials.

Impacts of physiological characteristics and human activities on the species distribution models of orchids taking the Hengduan Mountains as a case.

The biogeography research of orchids through species distribution models (SDMs), a vital tool in the biogeography field, is critical to understanding the fundamental geographic distribution patterns and identifying conservation priorities. The correspondence between species occurrence and environmental information is crucial to the model's performance. However, ecological preferences unique to different orchid species, such as their life forms, are often overlooked during the modeling process. This oversight can introduce bias and increase model uncertainty. Additionally, human activities, as an important potential predictor, have not been quantified in any orchid SDMs. Taking the Hengduan Mountains as an example, we preprocessed all orchid species' occurrences based on physiological characteristics. Choosing five spatial factors related to human activities to quantify the interference and enter into models as HI factor. Using different modeling methods (GLM, MaxEnt, and RF) and evaluation indices (AUC, TSS, and Kappa), diverse modeling strategies have been constructed in the study. A double-ranking method has been adopted to select the critical orchid distribution regions. The results showed that classification models based on physiological characteristics significantly improved the model's accuracy while adding the HI factor had the same effect but the absence of enough significance. Suitability maps indicated that highly heterogeneous mountainous areas were vital for the distribution of orchids in the Hengduan Mountains. Different distribution patterns and critical regions existed between various orchid life forms geographically - terrestrial orchids were dominant in the mountain, and mycoherterophical orchids were primarily located in the north, more influenced by vegetation and temperature. Critical regions of epiphytic orchids were in the south due to a greater dependence on precipitation and temperature. These studies are informative for understanding the orchids' geographic distribution patterns in the Hengduan Mountains, promoting conservation and providing references for similar research beyond orchids.

Hemipiliaavisoides (Orchidaceae), a new species from Sichuan Province, China.

A new orchid species, Hemipiliaavisoides, is described from Songpan County and Maoxian County, Sichuan Province, China. Morphologically, H.avisoides is most similar to H.hui, but can be distinguished by the combination of its involute middle lip lobe that is smaller than the lateral lobes, floral bracts that are 5 mm long and are always shorter than the ovary, a leaf that is appressed to the substrate and is adaxially green with white lines along 7-9 principal veins and the subterranean stem with a solitary sheath at its base. The floral morphology of H.avisoides is presented by utilising in vivo micro-CT scanning and 3D visualisation.

Effects of natural and artificial restoration on plant community characteristics of alpine cutting blank in Western Sichuan, China.

To investigate the plant community characteristics of alpine cutting blanks under different restoration approaches, we conducted a field survey on cutting blanks experienced either natural restoration (40 years) or artificial restoration (30, 40 and 50 years) in western Sichuan, with natural forests as the reference. Our results showed that after 40 years natural succession, cutting blank was replaced by the secondary shrub of Spiraea alpina, while artificial restoration plantation was dominated by Picea likiangensis var. rubescens. The similarity indices between these communities and natural forests were low (0.19) and medium (0.28-0.49), respectively. Cutting blank through natural and artificial restoration had lower species diversity in the shrub layer but higher diversity in the herb layer than that of natural forests. With the increases of recovery time, total cross-sectional area at breast height, wood volume, index of species diameter class distribution, diversity indices, and similarity indices between plantations and natural forests gradually increased, while stand density gradually decreased. Compared with natural forests, plantations were facing with problems including high stand density, unreasonable structure, pure stands of cohorts and poor regeneration.

Warming delays the phenological sequences of an autumn-flowering invader.

Phenology can play an important role in driving plant invasions; however, little is known about how climate warming, nitrogen (N) deposition, and invasion stages influence the phenological sequences of autumn-flowering invaders in a subtropical climate. Accordingly, we conducted an experiment to address the effects of experimental warming, N-addition, and community types on the first inflorescence buds, flowering, seed-setting, and dieback of invasive Solidago canadensis. Warming delayed the onset of first inflorescence buds, flowering, seed-setting, and dieback; N-addition did not influence these four phenophases; community types influenced the onset of first seed-setting but not the other phenological phases. Seed-setting was more sensitive to experimental manipulations than the other phenophases. The onset of first inflorescence buds, flowering, and seed-setting was marginally or significantly correlated with ramet height but not ramet numbers. Our results suggest that future climate warming might delay the phenological sequences of autumn-flowering invaders and some phenophases can shift with invasion stages.

Valid or not? Yunnan mountain snake Plagiopholis unipostocularis (Serpentes: Colubridae: Pseudoxenodontinae).

Plagiopholis unipostocularis Zhao, Jiang & Huang, 1978 is a small snake endemic to Yunnan, southern China. Its validity is still controversial and unresolved. Based on extensive sampling in Yunnan, we conducted morphological comparison and molecular phylogenetics on the unidentified specimens of Plagiopholis from Yunnan. Based on a combination of morphological comparison and molecular phylogeny, the newly collected specimens could be identified as P. blakewayi. While some specimens exhibit one or more diagnostics of P. unipostocularis, and some characteristics are intermediate between that of Plagiopholis unipostocularis and P. blakewayi. Thus morphological continuities between two species uncovered P. unipostocularis is a synonymy of P. blakewayi, and the diagnostics of this species was revised accordingly.

A congeneric comparison shows that experimental warming enhances the growth of invasive Eupatorium adenophorum.

Rising air temperatures may change the risks of invasive plants; however, little is known about how different warming timings affect the growth and stress-tolerance of invasive plants. We conducted an experiment with an invasive plant Eupatorium adenophorum and a native congener Eupatorium chinense, and contrasted their mortality, plant height, total biomass, and biomass allocation in ambient, day-, night-, and daily-warming treatments. The mortality of plants was significantly higher in E. chinense than E. adenophorum in four temperature regimes. Eupatorium adenophorum grew larger than E. chinense in the ambient climate, and this difference was amplified with warming. On the basis of the net effects of warming, daily-warming exhibited the strongest influence on E. adenophorum, followed by day-warming and night-warming. There was a positive correlation between total biomass and root weight ratio in E. adenophorum, but not in E. chinense. These findings suggest that climate warming may enhance E. adenophorum invasions through increasing its growth and stress-tolerance, and that day-, night- and daily-warming may play different roles in this facilitation.

Simulated warming differentially affects the growth and competitive ability of Centaurea maculosa populations from home and introduced ranges.

Climate warming may drive invasions by exotic plants, thereby raising concerns over the risks of invasive plants. However, little is known about how climate warming influences the growth and competitive ability of exotic plants from their home and introduced ranges. We conducted a common garden experiment with an invasive plant Centaurea maculosa and a native plant Poa pratensis, in which a mixture of sand and vermiculite was used as a neutral medium, and contrasted the total biomass, competitive effects, and competitive responses of C. maculosa populations from Europe (home range) and North America (introduced range) under two different temperatures. The warming-induced inhibitory effects on the growth of C. maculosa alone were stronger in Europe than in North America. The competitive ability of C. maculosa plants from North America was greater than that of plants from Europe under the ambient condition whereas this competitive ability followed the opposite direction under the warming condition, suggesting that warming may enable European C. maculosa to be more invasive. Across two continents, warming treatment increased the competitive advantage instead of the growth advantage of C. maculosa, suggesting that climate warming may facilitate C. maculosa invasions through altering competitive outcomes between C. maculosa and its neighbors. Additionally, the growth response of C. maculosa to warming could predict its ability to avoid being suppressed by its neighbors.

Maternal lineages of Pinus densata, a diploid hybrid.

Previous morphological, allozyme and chloroplast DNA data have suggested that Pinus densata originated through hybridization between P. tabuliformis and P. yunnanensis. In the present study, sequence and restriction site analyses of maternally inherited mitochondrial nad1 intron were used to detect variation patterns in 19 populations of P. tabuliformis, P. yunnanensis and P. densata. A total of three mitotypes (A, B, C) were detected. All but one of the populations of P. yunnanensis possessed mitotype B while all populations of P. tabuliformis had mitotype A. Pinus densata populations, on the other hand, harboured both mitotypes A and B, which are characteristic of P. tabuliformis and P. yunnanensis, respectively. This result gives strong additional evidence supporting the hybrid origin of this diploid pine. The distribution of mitotypes indicated very different mating compositions and evolutionary history among P. densata populations. It seems that local founder populations and backcrosses may have played important roles in the early establishment of P. densata populations. The uplift of the Tibetan Plateau had a significant impact on the distribution of maternal lineages of P. densata populations.