A 6‐m‐long sediment core from the King River region of north‐west Australia has been analysed using sedimentological and palynological techniques. The core spans most parts of the Holocene and contains a detailed record of early to mid‐Holocene landscape development. In the early Holocene an intertidal environment supported a diverse and probably extensive mangrove forest. Intensified fluvial activity, high mangrove biodiversity and the proximity of freshwater swamp vegetation reflect enhanced summer monsoon rainfall. From 7.4k cal a BP onwards, the mangrove forest starts to contract reaching minimum (and probably present‐day) extent by 6.5k cal a BP. Late Holocene aridification led to shifts in mangrove composition, the expansion of hypersaline flats and the transition of freshwater swamps to intermittent wetlands. In addition, fire potentially played an increasing role in controlling ecosystem composition, in particular in the savanna/woodland vegetation. This record is the first of its kind from coastal north‐west Australia and demonstrates that sea‐level and climatic fluctuations, in addition to local geomorphological settings, are major controllers of landscape development. Although the general pattern of change is similar to other sites in tropical Australia, detailed analysis shows that the timing and character of vegetation shifts are considerably different.

Abstract. Clouds and cloud feedbacks represent one of the largest uncertainties in climate projections. As the ice phase influences many key cloud properties and their lifetime, its formation needs to be better understood in order to improve climate and weather prediction models. Ice crystals sedimenting out of a cloud do not sublimate immediately but can survive certain distances and eventually fall into a cloud below. This natural cloud seeding can trigger glaciation and has been shown to enhance precipitation formation. However, to date, an estimate of its occurrence frequency is lacking. In this study, we estimate the occurrence frequency of natural cloud seeding over Switzerland from satellite data and sublimation calculations. We use the DARDAR (radar lidar) satellite product between April 2006 and October 2017 to estimate the occurrence frequency of multi-layer cloud situations, where a cirrus cloud at T < −35 ∘C can provide seeds to a lower-lying feeder cloud. These situations are found to occur in 31 % of the observations. Of these, 42 % have a cirrus cloud above another cloud, separated, while in 58 % the cirrus is part of a thicker cloud, with a potential for in-cloud seeding. Vertical distances between the cirrus and the lower-lying cloud are distributed uniformly between 100 m and 10 km. They are found to not vary with topography. Seasonally, winter nights have the most multi-layer cloud occurrences, in 38 % of the measurements. Additionally, in situ and liquid origin cirrus cloud size modes can be identified according to the ice crystal mean effective radius in the DARDAR data. Using sublimation calculations, we show that in a significant number of cases the seeding ice crystals do not sublimate before reaching the lower-lying feeder cloud. Depending on whether bullet rosette, plate-like or spherical crystals were assumed, 10 %, 11 % or 20 % of the crystals, respectively, could provide seeds after sedimenting 2 km. The high occurrence frequency of seeding situations and the survival of the ice crystals indicate that the seeder–feeder process and natural cloud seeding are widespread phenomena over Switzerland. This hints at a large potential for natural cloud seeding to influence cloud properties and thereby the Earth's radiative budget and water cycle, which should be studied globally. Further investigations of the magnitude of the seeding ice crystals' effect on lower-lying clouds are necessary to estimate the contribution of natural cloud seeding to precipitation.

The environmental history of Big Willum (Waandriipayn) Swamp and the surrounding landscape is reconstructed for the last 8000 years through the analysis of pollen, charcoal and mineral magnetics. The data provide a Holocene record of vegetation and fire in an area where few records exist. Swamp initiation at Big Willum began prior to 8000 cal. BP, with swamp-like conditions maintained until 2200 cal. BP, after which it became a permanent deep water body, reaching its present day extent between 600-400 cal. BP. From 7000-1200 cal. BP the surrounding woodland was essentially stable. Fire is present throughout the record, with only one period of pronounced burning outside of the historic period, at around 1000 cal. BP, leading to a slightly more open understorey/woodland. The hydrological change at 2200 cal. BP that led to Big Willum becoming a more permanent water body overlaps with the end of the most intensive period of shell mound formation and the commencement of earth mound building at nearby Wathayn. This is suggestive that change in, or diversification of, mound types may in part be linked to environmental transformations in the late Holocene. One possibility is that greater water security allowed for increasing and more permanent exploitation of inland locations.

The Niger Delta, being the most extensive freshwater wetland and aquatic ecosystem in West Africa, provides numerous services both to local people and to the West African economy. Ongoing environmental pressure exerted by large-scale oil extraction and illegal timber logging, however, are suspected to have had a substantial impact on the Delta’s ecosystems over the last decades. Knowledge on impact of these activities on the region’s wetlands now or in the past is scarce and patchy. To address this lack of knowledge, this study assesses spatiotemporal changes in two wetlands in the region by using satellite data from 1984 to 2011 and GIS methods. The results show that both wetlands have experienced substantial degradation, particularly with respect to the area of forest lost. Although comprehensive environmental protection laws were introduced in 1988, ecosystem services of up to US$65 million in value were lost over the study period. The introduction of new legislation in 2007, however, is potentially a first step towards a more ‘wise use’ of wetlands in Nigeria.

Vegetation changes of tropical Lizard Island (Great Barrier Reef World Heritage Area, Australia) over the last 8000 years are derived from palaeoenvironmental analysis of a 475 cm long sediment core. During early-Holocene sea-level rise, flooding of the continental shelf and thus isolation of Lizard Island, the pollen record shows the gradual establishment of a mangrove forest paralleled by contraction of the near-coastal palm and grass-dominated vegetation. Subsequently, mid-Holocene relative environmental stability supported a diverse, Rhizophora-dominated mangrove and open, mixed sclerophyll vegetation inland. Around 6000 years ago, a profound disturbance of the mangrove is recorded by a siliciclastic layer and we hypothesise that this deposit documents the impact of a storm or cyclone. Postevent environmental conditions were strongly altered with enhanced estuarine conditions supporting a Sonneratia and Bruguiera-dominated mangrove forest. During late-Holocene sea-level fall and stabilisation, progradation and contraction of the mangrove forest was paralleled by the expansion of a palm-dominated swamp. Freshwater taxa continued to dominate the record, however, a distinct disturbance signal from anthropogenic activity is recorded in the last century. Although Sonneratia dominated the post-event mangrove, late-Holocene environmental instability led to the extinction of this genus on the island. Local environmental changes in the freshwater swamp and rainforest also led to the loss of Arenga and Ilex from the island’s ecosystems. Our record implies that long-term ecosystem and biodiversity change on Lizard Island is: (a) primarily reflected in the spatial extent of the island’s vegetation communities and the species dominance within them and (b) driven by an interplay between climate, sea-level and potentially human activity. In addition, a short-term impact provoked the reconfiguration of the mangrove, potentially causing long-term ecosystem instability and thus impacting on mangrove biodiversity development on the Great Barrier Reef islands.