Plant Ecology

Sambucus javanica Blume is a Chinese native medicinal plant with high medicinal value. In this study, the MaxEnt model was used to explore the relationship between the geographical distribution of S. javanica and environmental factors, and to construct the distribution pattern of S. javanica under different climate scenarios. The results showed that the environmental conditions suitable for the distribution of S. javanica were as follows: precipitation in June ranged from 156.36 to 383.25 mm; solar radiation in December ranged from 6750.00 to 10,521.00 kJm−2day−1; isothermality ranged from 24.06 to 35.50; precipitation of warmest quarter ranged from 447.92 to 825.00 mm. Among them, precipitation and temperature were the key environmental factors affecting the distribution patterns of S. javanica. This plant could grow well mainly in two regions in China, covering a total area of 2.73 × 106 km2. The first region mainly consists of Guizhou, western Hubei, southeastern Chongqing, southwestern Hunan, northern Guangxi, and a small part of eastern Yunnan. The second region mainly consists of Zhejiang, southern Anhui, and northern Fujian. Under the future SSP126 and SSP585 scenarios, potentially suitable habitats in the eastern part of the potential distribution of S. javanica (Jiangxi, Fujian, Zhejiang, and Anhui) might be at risk of habitat fragmentation. Future climate change might have little effect on the distribution areas of S. javanica. But its suitable distribution has a tendency shift to higher altitude areas. Based on the result of this study, real-time monitoring of wild groups of S. javanica is now recommended to protect its genetic diversity. These findings are supposed to promote the effective conservation and utilization of S. javanica in the future.

The Sieversio montanae-Nardetum strictae is one of the most widespread plant communities in (sub-) alpine regions of the Alps. Our study examines the composition, ecology and distribution of this plant community in the Eastern Alps and addresses the issue of how the community is to be classified in the phytosociological system of Nardus-rich grasslands. Therefore, 357 vegetation relevés were taken from the literature and 115 from our own inventories were recorded from 2005 to 2007 in Western Austria (mostly Tyrol) and Northern Italy (mostly South Tyrol). Additionally, indicator values of Ellenberg and land-use information were used to help better interpret the ecological site conditions of the subgroups. The HCA revealed there the existence of four groups of the Sieversio montanae-Nardetum strictae, which were classified to subassociations: (1) typicum, (2) vaccinietosum, (3) trifolietosum pratensis, and (4) seslerietosum albicantis. Besides the specific plant composition, altitude specifies the first, land-use intensity the second and third, and the pH of the topsoil the fourth subassociation. For the Eastern Alps, the plant community of the Sieversio montanae-Nardetum strictae should now be reclassified in the order of Nardetalia and the class of Calluno-Ulicetea. Finally, this plant community can be further classified by using the four above-mentioned subassociations.

Melinis minutiflora Beauv. (Poaceae) is an African grass that is invading mid-elevation Trachypogon savannas in Venezuela. The objective of this study was to investigate the influence of soil fertility, competition and soil disturbance in facilitating Melinis' invasion and growth in these savanna sites. We manipulated soil fertility by adding nitrogen (+N), phosphorus and potassium (+PK), or nitrogen, phosphorus, and potassium (+NPK). We simultaneously manipulated the competitive environment by clipping background vegetation. In a separate experiment, we mechanically disrupted the soil to simulate disturbance. We hypothesized that germination and growth were bottlenecks to early establishment in undisturbed savanna, but that disturbance would alleviate those bottlenecks. We measured Melinis seed germination and subsequent establishment by adding seeds to all plots. We examined Melinis growth by measuring biomass of Melinis seedling transplants, 11 months after they were placed into treatment plots. Germination and establishment of Melinis from seed was extremely low. Of the 80,000 seeds applied in the experiment, only 28 plants survived the first growing season. Mortality of Melinis seedling transplants was lowest in PK fertilized plots, but in the absence of PK mortality increased with N additions and clipping. By contrast, fertilization of the savanna with NPK greatly increased Melinis seedling biomass and this effect was greatly enhanced when competition was reduced (e.g. clipping). Melinis transplant growth responded strongly to soil disturbance- a response not fully explained by removal of competitors (clipping) or changes in soil nutrients and moisture. We suspect that disruption of the soil structure allowed for greater root proliferation and subsequent plant growth. We believe that native savanna is relatively resistant to Melinis invasion, since Melinis seedlings persisted in intact savanna but exhibited little or no growth during the first year. The significant enhancement of Melinis seedling growth with clipping and nutrient additions suggests that low soil nutrients and the presence of native savanna species are important factors in the ability of native savanna to resist Melinis establishment. However, the potential for Melinis growth increases enormously with soil disturbance.

Hokkaido Island is located in the cool temperate zone, and its climate conditions facilitated the formation of a variety of wetland types, the majority of them peat-forming mires. Most of these remained in a natural state until the early 20th century. However, drainage and subsequent conversion mostly to agricultural land have since destroyed more than 70% of the original wetland ecosystems. This paper (1) provides an overview of mire types, (2) reviews the development process of mires in Hokkaido during the Holocene, (3) analyzes the causes of losses of wetland areas, and (4) gives a summary of the current conservation and management status. Basic mire types that have been described in other parts of the northern hemisphere can also be recognized in Hokkaido, although there are floristic differences, and the frequency and intensity of volcanic impact and tsunamis is higher than in most other regions with abundant mire formation. Mire formation started at various points during the postglacial period; a few mountain mires in southwest Hokkaido date back to the Lateglacial, but most mountain mires formed during the mid to late Holocene. Most lowland mires developed at altitudes below 20 m and were influenced by the Jomon transgression that peaked ca. 6,000 years BP. The largest lowland mires started forming after the sea retreated, and many are not older than ca. 3,000 years. In 1996, the total number of wetlands (including peat-forming mires, freshwater marshes, and saltmarshes) greater than 1 ha was 150, with a total area of 59,881 ha. In 1928, when many wetlands were yet undeveloped, their total area was 200,642 ha. Most losses occurred between the 1950s and 1970s, when post-war development economics promoted agriculture and large-scale reclamation projects. Currently, 90.7% of mountain wetlands are public land, while 81.3% of the lowland wetlands are private or in mixed ownership. The ownership condition affects the possibilities for the protection of complete mire complexes especially in the lowlands. For effective conservation of wetland ecosystems it is necessary to include the catchment area in the planning of protected areas.

Many plant seeds travel on the wind and through animal ingestion or adhesion; however, an overlooked dispersal mode may lurk within those dispersal modes. Viable seeds may remain attached or embedded within materials birds gather for nest building. Our objective was to determine if birds inadvertently transport seeds when they forage for plant materials to build, insulate, and line nests. We also hypothesized that nest-mediated dispersal might be particularly useful for plants that use mating systems with self-fertilized seeds embedded in their stems. We gathered bird nests in temperate forests and fields in eastern North America and germinated the plant material. We also employed experimental nest boxes and performed nest dissections to rule out airborne and fecal contamination. We found that birds collect plant stem material and mud for nest construction and inadvertently transport the seeds contained within. Experimental nest boxes indicated that bird nests were not passive recipients of seeds (e.g., carried on wind), but arrived in the materials used to construct nests. We germinated 144 plant species from the nests of 23 bird species. A large proportion of the nest germinants were graminoids containing self-fertilized seeds inside stems—suggesting that nest dispersal may be an adaptive benefit of closed mating systems. Avian nest building appears as a dispersal pathway for hundreds of plant species, including many non-native species, at distances of at least 100–200 m. We propose a new plant dispersal guild to describe this phenomenon, caliochory (calio = Greek for nest).