Palynological analysis of peat cores collected near two abandoned farms in the Svalbarðstunga Valley of the þistilfjorður region of northeastern Iceland was used to reconstruct the mid-Holocene vegetation history and to distinguish climatic and anthropogenic impacts on terrestrial ecosystems since colonization. The first site, Hjálmarvík, is located along the coast of þistilfjorður, while Kúðá is located 12 km inland. From 6430 to ca. 4500 cal BP, shrub tundra and birch woodland dominated the landscape. Between ca. 4500 and ca. 1170 cal BP, cooler and wetter conditions favored peatland species, while birch significantly declined. From 1170 cal BP to the present, grassland and peatland were prevalent. Birch woodland had virtually disappeared from the inland regions by 5810 cal BP and from the coast by 3450 cal BP. However, isolated trees persisted in certain areas. Following the initial Norse settlement of Svalbarðstunga at about 1000 AD, the development of agriculture and sheep grazing promoted the spread of sedges and facilitated the introduction of new plant species. Ecological changes linked to the Norse landnám were more limited in Svalbarðstunga than elsewhere in Iceland, where abrupt changes such as woodland clearance and erosion have been associated with human settlement.

Eriocheir sinensis, the Chinese mitten crab, has decreased dramatically in the Yangtze Estuary in recent years. Distribution of mitten crab larvae in the Yangtze Estuary and the influence of oceanographic features on their densities were analyzed based the samples collected from 27 stations in March, April and May 2013–2015. Results showed zoeae I and II began to appear in March, zoeae III and IV in April, and zoeae V and megalopae in May. The spatial patterns of zoeae II, III and IV were identified as having a highly clustered distribution. Habitats located near the mouth of the North Branch were mainly hotspots of each stage larvae. Both biotic (zooplankton biomass) and abiotic variables (water temperature and depth) had significant impacts on the larval densities. Compared with 1986–1988, the original nursery habitats have moved approximately 20–50′E towards the shore, and have locally lost the nursery function after the Three Gorges Dam (TGD) construction.

We combined dendroecological analyses with historical and ethnographic information to document connections between forest use patterns since the 18th century and stand composition and structure in the Nain region of Labrador, Canada. The highest recruitment periods for both eastern larch and spruce, pulses in growth releases, and decades with greatest harvesting evidence (cut stumps) all occurred primarily between 1910 and 1970. The strongest disturbance signal occurred after 1940, resulting in the absence of old trees and increased larch recruitment. The 1910–1970 period coincides with significant shifts in human settlement and land use patterns. Most notably, the increased demand for fur in the 1920s and 1930s changed Inuit land use: the Inuit spent more time inland where fur-bearing animals and wood resources were available. Moreover, population growth in Nain, which was accelerated by the relocation of Inuit communities in northern Labrador between 1950 and 1960, increased local harvesting intensity. We argue that long-term land use needs to be accounted for as a driver of forest dynamics in this subarctic forest landscape.

In Southeast Asia, intensive rainstorms caused by strong monsoon and tropical cyclones can trigger landslides in mountainous or hilly regions, which may significantly impact the natural terrains. This mostly includes the loss of vegetation cover, the emptying of seed banks and degradation of the top soil. The objective of this study was to assess the spontaneous vegetation regeneration on nine landslide trails approximately 2.5 years after disturbance. A systematic vegetation sampling was conducted using 5 × 5 m quadrats. A total of 1,304 individuals from 72 tree and shrub species were recorded across the landslide trails, with a mean density of 1.09 ± 0.71 individual m^-2. The woody component of the regeneration was dominated by birddispersed species, followed by wind-dispersed species. Ground cover was dominated by two matforming ferns Dicranopteris pedata and Blechnum orientale. In order to facilitate the vegetation restoration and to speed up ecological succession on landslides, it is recommended to establish pioneer trees to improve both the top soil stability and soil-building process. The importance of providing bird perches must be emphasized, as it improves seed rain to the disturbed landscapes, thus promoting the regrowth of trees and shrubs.

Dry coniferous forests within the wildland—urban interface (WUI) in the northwestern US have experienced long-term drought and increasing bark-beetle infestations. An unexamined factor potentially affecting WUI forests are irrigation channels used to convey water to nearby farms. I studied the effects of two irrigation channels (a downslope, open channel and an upslope, recently enclosed channel) on plant community composition, tree water status and growth, and patterns of bark-beetle mortality in a WUI ponderosa pine/Douglas fir forest experiencing drought. Low-lying swale areas below the recently enclosed, upper channel had extensive down dead wood and showed shifts from mesic understory plant species to more xeric species. Tree density and basal area declined in swale areas below both channels. Ponderosa pine below the enclosed channel showed evidence of water stress (low water potentials) and negative growth responses to the channel enclosure. In contrast, hillslope trees below the open channel had higher growth rates and water potentials compared to trees above that channel. Beetle-kill was highest between the two channels, the area most likely affected by upper channel enclosure. The study provides evidence that plant community composition, tree physiology, and patterns of tree mortality in forests may be affected by irrigation channels interacting with small-scale topography.

Secondary metabolites in the leachates of medicinal herbs inhibit forest litter decomposition, affecting interspecific relationships and nutrient cycling in the silvi-medicinal system. In this study, a typical forest species in the Qinling Mountains area, Catalpa fargesii Bur., and nine species of common understory medicinal herbs were used as example species. A litter decomposition experiment was carried out by treating the C. fargesii litter with stem and leaf leachates (simulated using water extracts) from the medicinal herbs to investigate the effects on forest litter decomposition, nutrient release and soil enzyme activity. Lachates from Mentha haplocalyx Briq., Houttuynia cordata Thunb., Gynostemma pentaphyllum (Thunb.) Makino and Prunella vulgaris L. exhibited significant inhibitory effects on the decomposition and nutrient release of C. fargesii litter and on the activities of related soil enzymes. Consequently, it is suggested that plantation of these four medicinal herb species should be avoided under C. fargesii forests or interplanting density must be low to reduce inhibitory effects on litter decomposition and nutrient release.

The invasive shrub Lonicera maackii (Amur honeysuckle) is a problematic species in the eastern United States and there is growing evidence that materials from this species have toxic effects on some organisms. We used a sequence of microcosm bioassays to assess the influence of L. maackii leaf leachate on the macroinvertebrate Hyalella azteca, which is a standard aquatic organism for toxicity assessment. In a laboratory setting, H. azteca were exposed to a leaf leachate dilution series (6.25%, 12.5%, 25%, 50%, 100%) in 48-h toxicity tests. This was repeated throughout the growing season to assess the potential for changes in leaf toxicity due to phenology. Strong toxic effects were found when H. azteca was exposed to a L. maackii leachate from autumn (P < 0.05) and, in fact, all organisms died when exposed to any level of concentration in most trials. Mean percent survival also decreased significantly in all dilutions in the spring (P < 0.05 for all treatments); however, little toxicity was detected in growing season trials. These results suggest (a) strong toxic effects of L. maackii foliage on a model aquatic organism that (b) varies throughout the year, potentially in relationship to biochemical changes associated with phenology.

Nest predation is one of the most important causes of nest failure in breeding birds and can vary extensively between sites and years. Different mechanisms governing predation rates may dominate in different years and this annual variation should therefore be evaluated directly. Here we document year-to-year variation in nest predation rates in two ecosystems (forest and salt meadows) within the mid-boreal forest zone to evaluate whether annual variation in nest predation rates are linked with annual variation in predator identity or the ratio between predator types. Year-to-year variation in predation rates was low in all experiments (non-significant differences in experiments 1 and 2), with a significant decrease only from 2005 (0.90%) to 2008 (0.70%), 2009 (0.65%) and 2010 (0.72%) in experiment 3. In addition, random intercept estimates indicated that two sites from experiment 1 showed higher predation rates in year 2 than in year 1. None of these differences were related with differences in apparent predator community structure or predator identity. This suggests that low between-year variation in nest predation rates may be common in areas where the predator communities are stable, and the existing variation cannot be explained by variation in predator identity alone.