It is well known that the population structure of plants in permanent plots change from year to year. Species abundances probably shift with time due to both species biology and variation in environmental factors. The main purpose of the study has been to describe and analyse long-term variation in the abundance (coverage) of blister sedge Carex vesicaria and reed canary grass Phalaris arundinacea in relation to time and space after a permanent lowering of a lake water level and exposition of new areas for species colonization. The study area lies in outer edge of a freshwater fluvial delta in the northern part of the Myrkdalen lake (229 m a.s.l.) West Norway, which was exposed after a permanent 1.4 m lowering of the summer water level in 1987. A 40 m long transect with ten 0.5 m × 4 m plot was established on the lower parts of the exposed delta in 1987. Study plots were situated at mean heights between 13 and 92 cm above the new summer water level. Floristic composition of the plots was monitored and analysed from 1988 to 2020, a total of 19 times. The plants show major differences in establishment, growth, and long-time dynamics in the permanent plots. The coverage of C. vesicaria and P. arundinacea was highly variable over the study period. Variations in coverage were related to time using regression analyses. The trends were mostly best described by cubic functions. Both species showed relatively low coverages between 18 and 26 years after the lake water drawdown, but increased again over the last study periods. Maximum coverage of the species was in time gradually separated by elevation. C. vesicaria became dominant in plots less than ca. 50 cm above the mean summer water, and P. arundinacea reached higher coverage above that elevation. The study indicates that elevation, as a proxy for flooding duration, and not aboveground species competition was the main factor for this difference in distribution.

One of the main factors in the successful invasion of invasive plants is their allelopathy on the growth performance (especially seed germination and seedling growth) of neighboring plants. Salt stress, mainly mediated by soil salinization, may affect or even facilitate the process of invasion of invasive plants via their allelopathy. The aim of this study was to evaluate the allelopathy effect of four Asteraceae invasive plants, including Canada goldenrod (Solidago canadensis L.), horseweed (Conyza canadensis (L.) Cronq.), rallway beggaricks (Bidens pilosa L.), and daisy fleabane (Erigeron annuus (L.) Pers.), on seed germination and seedling growth of the horticultural Asteraceae species Lactuca sativa L. under a gradient of salt stress in an hydroponic incubation experiment. Salt stress significantly reduced seed germination and seedling growth of L. sativa. These four invasive plants are known to negatively affect seed germination and seedling growth of L. sativa through their allelopathy. The allelopathy of S. canadensis was stronger than that of the three other invasive plants. Salt stress significantly intensified the allelopathy of the four studied invasive plants (especially S. canadensis), and the facilitation of salt stress on the allelopathy of the four invasive plants (especially S. canadensis) significantly increased with increasing intensity of salt stress. Therefore, the increased level of salt stress may facilitate the process of invasion of the four studied invasive plants (especially S. canadensis) via their increased allelopathy negatively affecting the seed germination and seedling growth of neighboring plant species.

In 2016/2017 austral summer, individuals of all charadriiform species were counted on selected sections of the Atlantic coastline between Cape Cross and Walvis Bay in Namibia, southern Africa (in total 72 km of coastline). Results were compared with similar data obtained in these sections forty years earlier (1976/1977 austral summer). Most wader species have showed decline, while most gulls and terns – increase in numbers. In overall, the Palearctic waders were more numerous in 1976/1977 (N = 9523 birds) than in 2016/2017 (N = 1164 birds) by the order of magnitude. In both periods the most numerous species were the ruddy turnstone Arenaria interpres and sanderling Calidris alba. Among Lari, numbers of Damara tern Sternula belaenarum has decreased by the order of magnitude, numbers of the kelp gull Larus dominicanus has significantly increased, while numbers of Hartlaub's gull Larus hartlaubii remained similar in both years compared. All these gull species are breeding residents in Namibia. The only Palearctic tern species, the common tern Sterna hirundo was vagrant in 19976/1977, while in 2016/2017, it was not recorded at all. Changes in the number of Palearctic shorebirds recorded in the coastline between Cape Cross and Walvis Bay may could have been caused probably mainly by human disturbance. Changes in numbers of waders in other wintering places in South Africa were also reviewed.

Mobbing is a common anti-predatory behavior in birds consisting of loud calls to alert other individuals in the vicinity and aggressive displays in order to drive away a predator. In spite of the extensive bibliography available regarding mobbing behaviour, little is known about how mobbing varies across species inhabiting the same area. Here, we aimed to compare the mobbing response of four Iberian passerine species: the azure-winged magpie (Cyanopica cooki), the spotless starling (Sturnus unicolor), the great tit (Parus major) and the common blackbird (Turdus merula). To elicit mobbing response in free ranging birds we used a stuffed model of tawny owl (Strix aluco) along with playbacks of calls of this species. We analysed the frequency of observed mobbing events in each species, the mobbing intensity and its duration. Results showed that mobbing displays in C. cooki and S. unicolor were performed in bigger groups in comparison with T. merula and P. major, however, the duration of the mobbing response was shorter. Moreover, we found the lowest level of mobbing intensity in T. merula, the most solitary species studied. Our findings indicate that mobbing varies across species in the same area, suggesting that birds adapt mobbing behavior to the particular characteristics of their species and that social complexity might influence these differences.

The expansion of invasive alien species is a major threat to the environment and economy. Animal invasions, especially by raccoons Procyon lotor are increasingly harmful. Raccoons' reduced neophobia enables easy adaptation to humans and surroundings. They exploit human presence in their natural habitat. Camera traps and direct observations in Germany's Lower Oder Valley National Park and Poland's Lower Oder Valley Landscape Park revealed raccoons' cognitive abilities and effective learning processes. This study demonstrates their rapid learning in finding and opening traps, removing bait, killing and eating trapped rodents. To minimize disturbance by raccoons, we recommend to preselect study plots without raccoons or to use of protective devices.