Effects Of Anthropogenic Disturbance Research Articles

Effect of anthropogenic disturbance on biomass allocation to different above- and below-ground vegetation components of a dry tropical forest in India

Effect of anthropogenic disturbance on biomass allocation to different above- and below-ground vegetation components of a dry tropical forest in India

Deep seafloor hydrothermal vent communities buried by volcanic ash from the 2022 Hunga eruption

Mass mortality of marine animals due to volcanic ash deposition is present in the fossil record but has rarely been documented in real time. Here, using remotely-operated vehicle video footage and analysis of ash collected at the seafloor, we describe the devastating effect of the record-breaking 2022 Hunga submarine volcanic eruption on endangered and vulnerable snail and mussel species that previously thrived at nearby deep-sea hydrothermal vents. In contrast to grazing, scavenging, filter-feeding, and predatory vent taxa, we observed mass mortality, likely due to smothering during burial by thick ash deposits, of the foundation species, which rely on symbiotic chemosynthetic bacteria for the bulk of their nutrition. This is important for our broad understanding of the natural disturbance of marine ecosystems by volcanic eruptions and for predicting the effects of anthropogenic disturbance, like deep-sea mining, on these unique seafloor habitats.

Electrosensory and metabolic responses of weakly electric fish to changing water conductivity.

Weakly electric Gymnotiform fishes use self-generated electric organ discharges (EODs) to navigate and communicate. The electrosensory range for these processes is a function of EOD amplitude, determined by the fish's electric organ (EO) output and the electrical conductivity of the surrounding water. Anthropogenic activity, such as deforestation, dams, and industrial/agricultural runoff, are known to increase water conductivity in neotropical habitats, likely reducing the electrosensory range of these fish. We investigated whether fish modulate EO output as means of re-expanding electrosensory range after a rapid increase in water conductivity in the pulse-type Brachyhypopomus gauderio and the wave-type Eigenmannia virescens. Furthermore, because EOD production incurs significant metabolic costs, we assessed whether such compensation is associated with an increase in metabolic rate. Following the conductivity increase B. gauderio increased EOD amplitude by 20.2±4.3% over six days but with no associated increase in metabolic rate, whereas the EOD amplitude of E. virescens remained constant, accompanied by an unexpected decrease in metabolic rate. Our results suggest that B. gauderio uses a compensation mechanism that requires no metabolic investment, such as impedance matching, or a physiological tradeoff wherein energy is diverted from other physiological processes to increase EO output. These divergent responses between species could be the result of differences in reproductive life history or evolutionary adaptations to different aquatic habitats. Continued investigation of electrosensory responses to changing water conditions will be essential for understanding the effects of anthropogenic disturbances on gymnotiforms, and potential physiological mechanisms for adapting to a rapidly changing aquatic environment.

A meta‐analysis of the effects of anthropogenic disturbances on tropical mammal functional diversity

Abstract Understanding the processes that shape biological communities under a variety of perturbations is a central challenge in ecology and conservation. Mammals contribute to critical functional processes of an ecosystem, such as seed dispersal to maintain forest carbon stocks. The analysis of functional diversity, which measures the range and value of the ecological traits of organisms, provides critical information to understanding the link between biodiversity and ecosystem functioning. A growing number of studies have investigated the effects of anthropogenic disturbances on mammalian functional diversity; however, their results are very heterogeneous. Here, we conduct a comprehensive meta‐analysis of the effects of such anthropogenic disturbances on mammalian functional diversity in the tropics. We highlight major trends and analyse the influence of the type of anthropogenic disturbance, subgroups, and the functional diversity index used/applied. Our results indicate a negative effect of anthropogenic disturbances on mammalian functional diversity, particularly on functional richness (FRic) and functional dispersion (FDis). Habitat isolation was the stressor with the strongest effect, while agriculture and urbanisation showed a positive link with functional diversity. These results indicate that anthropogenic disturbances not only affect taxonomic diversity, but also reduce the functional diversity of mammals, which is likely to affect ecosystem functioning and possibly ecosystem service provision.

Disturbance and diversity: Lichen species richness decreases with increasing anthropogenic disturbance

Anthropogenic disturbance is rapidly increasing through habitat degradation, development, and deforestation. Gaps remain in understanding the effects of this disturbance on diverse and ecologically important organisms such as lichens. In North America, studies have focused on epiphytic macrolichens and catastrophic disturbance, largely ignoring microlichens and less severe disturbances. The Intermediate Disturbance Hypothesis predicts these moderate disturbances will lead to higher species richness. Here we examine the effects of anthropogenic disturbance in the form of land management on overall lichen richness, including microlichens, and on the species richness of eight lichen functional groups. The study draws on a comprehensive data set of 872 species, in 208 one-hectare plots throughout the Southern Appalachian Mountains, a global biodiversity hotspot in eastern North America. A habitat quality index based on an established forestry metric was used as a proxy for anthropogenic disturbance and was quantified using a 10-part score including categories such as percent native tree canopy cover and degree of fragmentation. Linear models were used to compare habitat quality scores to overall species richness and to species richness of functional groups. Rather than following the Intermediate Disturbance Hypothesis, all groups uniformly follow a negative linear relationship: as disturbance increases, species richness decreases. This pattern held even for widely variable functional groups such as morphotype. Effective conservation of lichen richness should prioritize the maintenance of existing older, less-disturbed stands within large, contiguously forested areas.

Change of spermatophyte family diversity in distribution patterns with climate change in China

The global climate is undergoing extraordinary changes, profoundly influencing a variety of ecological processes. Understanding the distribution patterns and predicting the future of plant diversity is crucial for biodiversity conservation in the context of climate change. However, current studies on predictive geographic patterns of plant diversity often fail to separate the effects of global climate change from other influencing factors. In this study, we developed a spatial simulation model of spermatophyte family diversity (SSMSFD) based on data collected from 200 nature reserves covering approximately 1,500,000 km2, where direct anthropogenic disturbances to plant diversity and the surrounding environment are absent. We predicted the spermatophyte family diversity for all provinces in China in 2020, 2040, and 2080, considering the impacts of global climate change. On average, China currently exhibits 118 plant families per 25 km2, with a decreasing trend from southeast to northwest. When considering only the effects of global climate change, excluding direct anthropogenic disturbances, our results indicate that under the Shared Socioeconomic Path Scenarios (SSPs) 245 and 585, spermatophyte family diversity is projected to slowly increase in most Chinese provinces from 2021 to 2080. Notably, the increase is more pronounced under SSPs585 compared to SSPs245. Global climate change has a positive effect on plant diversity, in contrast to the negative impact of anthropogenic disturbances that often lead to declines in plant diversity. This research highlights the contrasting outcomes of future plant diversity under the sole influence of global climate change and the significant negative effects of anthropogenic disturbances on diversity.

THREE-DECADE changes of reef cover in Pulau Layang-Layang, Malaysia using multitemporal Landsat images

Over the years, coral reefs in the South China Sea have degraded and faced severe threats from rapid development, coral bleaching, and Crown-of-Thorns Starfish (COTS) outbreak. There is limited knowledge relating to the effects of anthropogenic disturbances and natural events on the coral reefs of Pulau Layang-Layang. This study aims to assess reef cover changes by utilizing Landsat satellite images spanning from 1989 to 2022. Using the object-based image analysis method, this study classified the reef cover into three categories: coral, rock and rubble, and sand. The supervised classification had an overall accuracy of 86.41–87.38 % and Tau's coefficients of 0.80–0.81. The results showed island development and construction of artificial bird sanctuary have led to an increase in coral cover. Furthermore, it was illustrated that the impact of COTS outbreaks in 2010 and 2020 differed significantly, with the latter showing no signs of recovery. Our study underscores the importance of timely intervention to mitigate the spread of COTS. This study provides insights into the resilience and vulnerability of these ecosystems in the face of various stressors.

Conserving dipterocarps biodiversity in remnant forests of small islands in Batam Island, Indonesia

Abstract. Susilowati A, Wijaya K, Mawazin, Rachmat HH, Lismayati Y, Kurniawan H, Ginting IM. 2024. Conserving dipterocarps biodiversity in remnant forests of small islands in Batam Island, Indonesia. Biodiversitas 25: 726-733. The protected forest of Sei Harapan is a remnant forest in Batam Island, the Riau Islands Province, Indonesia and one of the keruing (Dipterocarpus spp.) habitats on Sumatra Island. Illegal logging for its wood and land degradation have significantly reduced the keruing population. The objective of this research was to assess the diversity of keruing species and floristic composition in the Sei Harapan Protected Forest. This study employed a vegetation analysis method using purposive sampling with plotted lines and the transect placement based on the keruing position. The research revealed more than 70 species, three of which were Dipterocarpaceae species, including Vatica pauciflora, Shorea curtisii, and Dipterocarpus rigidus. D. rigidus had the highest IVI at the sapling (52.80%) and pole (67.22%). However, D. rigidus ranked 13th in the seedling stage, with an IVI of 5.79%. The diversity index was high at the seedling stage (3.73), moderate at sapling (2.25), pole (2.76), and tree stage (2.89). The evenness index was high at all growth stages, with values of 0.94 (seedling), 0.98 (sapling), 0.91 (pole), and 0.81 (tree). The richness index at the seedling, pole, and tree stage were categorized as high, with values of 10.40, 5.39, and 7.09, respectively, whereas the richness index at the sapling stage was moderate at 3.51. The study finding pointed out that the existence of Sei Harapan remnant forest requires to be preserved considering its essential function for preserving high economic value tree species, especially Dipterocarp. The comprehensive conservation effort for dipterocarps species, is crucial considering the research findings revealed a problem of continuity of species regeneration and the emergence of new pioneer species as the consequence of anthropogenic disturbance.

Accelerated human-induced extinction crisis in the world's freshwater mammals

Human activities have significantly impacted natural habitats and wildlife worldwide, particularly emphasizing repercussions for freshwater habitats and associated species. These negative impacts on freshwater fish are well known, but for mammal species that regularly use and dependend on freshwater systems, there is an incomplete understanding. Here, we assessed the status of freshwater and semi-aquatic mammal species inhabiting and dependent on freshwater ecosystems (hereafter referred to as freshwater mammals) and evaluated the impact of human activities on species richness both globally and by biogeographical regions. We used structural equation modeling and simultaneous autoregressive models to assess the direct and indirect effects of seven anthropogenic-related variables on overall freshwater mammal richness. Specifically, we examined the effects of anthropogenic disturbance on the richness of threatened and non-threatened species, as well as species with decreasing and stable/increasing populations. Forty-three percent of all freshwater mammal species are classified as globally threatened by the IUCN Red List, with 50% experiencing population declines. Furthermore, 48% are affected by domestic or international trade, while 75% face threats from geographically expanding human activities. Aridity, pesticide pollution, human footprint, and croplands had the strongest negative effects on freshwater mammal richness. In contrast, the coverage of freshwater habitats (FWs), Indigenous Peoples' lands (IPLs), and protected areas (PAs) helped to sustain freshwater mammal species globally, with an even stronger positive effect at individual biogeographical regions. We conclude that FWs, IPLs, and PAs play a critical role in the conservation of freshwater mammal species, helping safeguard these species from extinction, however, freshwater ecosystems are seldom the focal point of conservation management strategies. The ongoing adverse anthropogenic impacts on these natural habitats present a potentially catastrophic and irreversible threat to global freshwater environments and the species, including humans, reliant upon them. We strongly advocate for the implementation of more robust national and international policy frameworks that endorse alternative and sustainable livelihoods. Such frameworks can play a crucial role in alleviating anthropogenic pressures, thereby aiding in the mitigation of the extinction risk faced by these vital ecosystems and the world's freshwater mammal species.

Synergistic effects of anthropogenic disturbances on giant pandas

AbstractLivestock grazing and the collection of bamboo shoots are the main threats to giant panda (Ailuropoda melanoleuca) habitat in the Liangshan Mountains in China. It is important to clarify the effect of these disturbances to the giant panda to formulate targeted management policies. Based on species distribution models and daily activity models, we investigated the effects of livestock grazing and bamboo shoot collection on giant pandas from May 2021 to July 2022. Our results indicated the giant panda's suitable habitat in the reserve covered 51.83 km2 (15.02% of the reserve area). Grazing and bamboo shoot collection led to losses of 19.08 km2 and 7.68 km2 of suitable habitat, respectively. Together, the 2 activities resulted in a loss of 28.35 km2 of suitable habitat, which was more than half of the area of panda habitat. The areas of suitable habitat for giant pandas significantly overlapped with the areas affected by both disturbances. Giant pandas did not show significant differences in daily activity rhythms under a single disturbance, but the daily activity rhythms of giant pandas differed when we compared the area combining the 2 disturbances with the undisturbed area. Our study reveals that the anthropogenic disturbances in the reserve have varying effects on the suitable habitat range and daily activity rhythm of giant pandas and evidence of a synergistic effect. Therefore, when formulating relevant conservation policies, it is important to fully evaluate the extent and characteristics of anthropogenic disturbances in shaping the population distribution and habitat preferences of the giant panda and other wildlife to enhance the efficacy of conservation management practices.

Effects of anthropogenic disturbance and land cover protection on the behavioural patterns and abundance of Brazilian mammals

Governmental and private protected areas are a key focus of conservation concern, as they tend to be associated with greater biodiversity and abundance of threatened mammals than non-protected areas. Protected areas are also effective at limiting anthropogenic pressures that threaten endemic species. Behavioural shifts are often the most immediate response of animals to disturbance, indicating the importance of considering the direct links between the disturbance present in an ecosystem and the behavioural patterns of endemic species. Here, we assessed the effect of land cover protection along with anthropogenic disturbance factors (human and dog abundance, distance to the nearest house, percentage of native vegetation [relative to agricultural landscapes]) on the activity patterns and abundance of 6 mammal species in the Brazilian Atlantic Forest and Cerrado. Data were collected using camera traps employed during 2 dry seasons at 208 stations (6240 camera-days). Activity pattern analyses used the novel application of circular activity patterns and a direct circular outcome to assess the direct impact of protection status and anthropogenic disturbance on behavioural shifts in the mammal species. Relative abundance was calculated using the mean population size of individuals as well as the per-individual detection probability. Protection status significantly elicited behavioural shifts in 5 of the 6 mammals, with 4 of these mammals shifting more towards nocturnality in non-protected areas. Dog abundance was the most important covariate in activity pattern shifts in the giant anteater, with nocturnality increasing with dog abundance, whereas native vegetation was the most important covariate in activity pattern shifts in the agouti and puma, with nocturnality increasing with decreasing native vegetation. Relative abundance was significantly lower in non-protected areas in 2 mammals, one of which was the Vulnerable giant anteater. The findings here are the first time in which anthropogenic disturbance factors have been found to directly elicit shifts in the circular activity patterns of mammals, as well as highlight the importance of protected areas in mammal conservation. The methods used here can be applied to ecosystems globally to pinpoint the direct impact of disturbance factors on endemic species whilst also providing explicit information on how conservation initiatives can be strategically and effectively targeted.

Combining bioenergetics and movement models to improve understanding of the population consequences of disturbance

We developed dynamic bioenergetics models to investigate how behavioural responses to anthropogenic disturbance events might affect the population dynamics of three marine mammal species (harbour porpoise, grey seal and harbour seal) with contrasting life‐history traits (capital versus income breeders) and movement behaviour (resident versus nomadic). We used these models to analyse how individual vital rates were affected by differences in the probability of disturbance and the duration of any behavioural response, while taking account of uncertainty in the model parameters and heterogeneity in behaviour. The outputs of individual movement models and telemetry data were then used to determine how the probability of exposure might vary among species, individuals, and geographical locations. We then demonstrate how these estimated probabilities of exposure can be translated into probabilities of disturbance. For illustrative purposes, we modelled the potential effects of a temporary decrease in energy assimilation associated with a series of disturbance events that might realistically occur during the construction of an offshore windfarm. Offspring starvation mortality was the vital rate that was most affected by these disturbance events. Monitoring of rate should be considered as standard practice so that populations responses can be detected as early as possible. Predicted effects on individual vital rates depended on the species' movement behaviour and the likely density of animals where the modelled construction activity was assumed to take place. The magnitude of these effects also depended critically on the assumed duration of the reduction in energy assimilation. No direct estimates of this variable are currently available, but we suggest some ways in which it could be estimated. The described approach could be extended to other species and activities, given sufficient information to parameterise the component models. However, we emphasise the need to account for among‐individual heterogeneities and uncertainties in the values of the many model parameters.

Influence of Elevation and Anthropogenic Disturbance on Woody Species Composition, Diversity, and Stand Structure in Harego Mountain Forest, Northeastern Ethiopia

Environmental variables like elevation affect species composition, diversity, distribution, density, and horizontal and upward growth. Ecologists are constantly working to better understand how species diversity varies along elevational gradients, particularly in mountainous ecosystems. Therefore, the purpose of this research was to examine the species’ horizontal and vertical structural diversity along the Harego Mountain Forest’s elevational gradient. The area was categorized into lower, middle, and upper elevations. A total of 67 (20 m × 20 m) plots were created along gradients of elevation 2,079–2,516 meters above sea level (m a.s.l.). Information for floristic composition, diversity, stand structure, and environmental variables were measured and recorded for each plot over the three elevational gradients. Data on anthropogenic disturbances were visually evaluated for every plot in every gradient of elevation. For the diversity analysis, Hill’s diversity statistics were employed. To find significant variations between the three elevational gradients in terms of Hill’s diversity number, stand structure, and environmental variables, the one-way analysis of variance with SPSS version 26 at the 0.05 level of significance was carried out. The finding revealed that 50 woody plants that belonged to 35 families and 44 genera in the 67 sample plots with an elevation of 2,079 to 2,516 were identified. Shrubs were dominant in each elevational gradient. Species richness, abundance, and Hill’s diversity number were all significantly ( p < 0.05 ) greater in the upper elevational gradient of the forest. On the other hand, all stand structures were significantly ( p < 0.05 ) higher in the middle elevational gradient. The effect of anthropogenic disturbances and environmental variables were clearly observed in the lower and upper elevational gradients than in the middle elevation. As a result, there were fewer seedlings, saplings, trees, and shrubs in the gradients of lower and higher elevations. For the conservation of the forest, it is crucial to pay special attention to biotic elements at lower elevations and abiotic factors at higher elevations. Accordingly, involving the local community in forest management, reducing anthropogenic pressure in and around the Harego Mountain Forest through tree planting in farmlands and woodlots and implementing physical soil and water conservation structures are recommended.

Anthropogenic disturbance affects specialist, but not generalist, endophagous insects associated with two African grasses: implications for biological control

ABSTRACT The specialisation-disturbance hypothesis (SDH) predicts that specialist and generalist taxa respond differently to disturbance, with generalists more tolerant of disturbance, while habitat stability (i.e. no/limited disturbance) should favour specialist species. If the SDH holds true, this would have implications for the design and implementation of biological control programmes, in terms of performing native-range surveys in search of candidate agents and subsequent development of management programmes for their release in the weeds invaded range. We assessed the effect of anthropogenic disturbance (mowing/slashing and fire) on the endophagous insect communities associated with two African grasses, Sporobolus pyramidalis and Sporobolus natalensis (Poaceae), that are targets for biological control in Australia. Comparisons, of insect community structure and presence/abundance of each species between disturbed and undisturbed sites, were made at 19 sites in South Africa. Disturbance caused a shift in insect species composition and abundance, whereby specialist insects were less frequently encountered and less abundant at disturbed versus undisturbed sites. If the potential agents for Sporobolus spp. are released in Australia they may be negatively affected by disturbance and may therefore be incompatible with certain integrated management strategies, such as mowing and prescribed burning. Moreover, our results suggest that field sites with limited disturbance should be prioritised during native-range surveys to maximise the chances of locating specialist natural enemies. The effect disturbance has on insect community composition may be particularly relevant for the biological control of invasive grasses, due to the intensity of disturbance of grasslands worldwide.

The effects of anthropogenic disturbance and seasonality on the ant communities of Lang Tengah Island.

Anthropogenic disturbances and seasonal changes significantly impact diversity and community composition of ants, but their effects are often intertwined. We investigated these drivers on Lang Tengah Island, a location with a pronounced monsoon season and three resorts that close during this period. We surveyed four sites, two disturbed and two undisturbed, before and after the monsoon season, using pitfall traps to sample epigaeic ant communities. Undisturbed habitats had higher species diversity, but both habitats (undisturbed and disturbed sites) have a high proportion of ants with characteristics of being encroached by generalist and invasive/tramp ant species. Post-monsoon sampling yielded an increase in species richness and diversity. Seasonal changes, such as monsoonal rains, can temporarily alter ant interactions and resource distribution, potentially maintaining diversity. Future studies should validate these findings for ant communities under similar pressures, using ant composition and functional roles for conservation and management purposes.

The Effects of Anthropogenic Disturbances on the Spatiotemporal Patterns of Medium-Large Mammals in Tropical Volcanic Landscapes.

A comprehensive understanding of the consequences of human interactions with mammals is a critical factor in supporting and conserving species in landscapes dominated by humans, which are increasingly threatened. This study aimed to identify the spatial and temporal interactions between humans and mammals. A non-parametric statistical approach with kernel density was used to detect human-mammal temporal interactions. The species interaction factor (SIF) was applied to calculate the spatial overlap based on the two-species occupancy detection model. The activity patterns of medium mammals were nocturnal, diurnal, and cathemeral. The human-medium mammal pairs with SIF values that were <1 and statistically significant included the human-long-tailed macaque (Macaca fascicularis) pair, the human-leopard cat (Prionailurus bengalensis) pair, and the human-barking deer (Muntiacus muntjac) pair. Based on their SIF values and the high overlap in their activity times, the human-macaque pairings had a high risk of conflict. Barking deer and leopard cats displayed a coexistence with humans via time-sharing activities. Due to temporal niche variations with human activities, the existence of nocturnal mammals was relatively uninterrupted. This study showed that most mammals are able to adapt spatially and temporally to various human activities. Nonetheless, efforts to mitigate human-wildlife conflict must be maintained, particularly in the case of severely endangered species, such as the Sunda pangolin.

Meiofauna: Anthropogenic impacts on hidden players in ecosystem

AbstractCertain aspects of meiobenthos research are given detailed and comprehensive attention in Chapter 7 (Hidden players: meiofauna mediate ecosystem effects of anthropogenic Disturbances in the ocean) of the Springer publication ‘New Horizons in Meiobenthos Research; Profiles, Patterns and Potential’ (O. Giere &amp; M. Schratzberger (Eds.). This book review is concerned solely with Chapter 7 which underlines the view that meiofaunal species play a very important part as hidden players in the impacts of anthropogenic disturbances in the ocean, an aspect justifiably arousing global concerns. The chapter constitutes a veritable compendium where much that was previously unsuspected in those ‘untouched reaches’, is revealed under the scrutiny of its many internationally known authors. Of its ten sections, eight deal consecutively with the impact of disturbances caused by anthropogenic activities such as bottom fishing, pollution from organic sources, hydrocarbons, oil and chemical impacts, invasive species and climate change, followed by a section on the resilience of the meiofauna to such disturbances and the scale of their responses, with a final section outlining a forward perspective for future research. In addition, Chapter 7 contains an extensive bibliography which itself constitutes an important reference resource for researchers.

Effects of Anthropogenic Disturbance and Seasonal Variation on Aerobiota in Highly Visited Show Caves in Slovenia.

Aerosols in caves are natural tracers and, together with climatic parameters, provide a detailed insight into atmospheric conditions, responses to climatic changes and anthropogenic influences in caves. Microbiological air monitoring in show caves is becoming increasingly useful to understand changes in cave ecosystems and to implement and review measures for sustainable cave use and tourism development. In 2017 and 2018, air along tourist trails in caves Postojnska jama and Škocjanske jame (Slovenia) was sampled before and after tourist visits. Samples were analysed using culture-dependent methods, flow cytometry, detection of β-D-glucan and lipopolysaccharide and compared with CO2 and temperature data to measure anthropogenic influences and seasonality on aerobiota. While the presence of tourists significantly increased concentrations of airborne microorganisms (p < 0.05), β-D-glucan and CO2 did not show such a trend and were more dependent on seasonal changes. Locally, concentrations of cultivable microorganisms above 1000 CFU/m3 were detected, which could have negative effects on the autochthonous microbiota and possibly on human health. A mixture of bacteria typically associated with humans was found in the air and identified with MALDI-TOF MS. Using MALDI-TOF MS, we achieved a 69.6% success rate in identification. Micrococcus luteus, Streptococcus mitis, Staphylococcus epidermidis and Moraxella spp. were recognized as good indicators of cave anthropisation.

Effect of typhoons on spatiotemporal patterns of multi-group persistent organic pollutants in sediment of Chinese southeastern coastal estuaries

Estuaries are susceptible to both anthropogenic disturbances and global climate changes. Impacts may be discriminated by pollution patterns of widely quantified persistent organic pollutants (POPs), though data are scarce for extreme climate events. This study quantified four groups of POPs, i.e., polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), and hexachlorocyclohexanes (HCHs), in sediments from seven Chinese coastal estuaries across a gradient of socioeconomic development in their watersheds with comparisons among the pre-typhoon, typhoon, and post-typhoon periods during 2016–2019. The maximal average concentrations, up to 1561 μg PAHs kg−1, 235 μg DDTs kg−1, and 38.9 μg HCHs kg−1, were quantified in the Jiulong River estuary and 7.61 μg PCBs kg−1 in the Jiao River estuary. Anthropogenic activities contributed to the distinctive spatial distributions of four groups of POPs in estuaries with non-agricultural gross domestic product (NAGDP) per capita significantly relating to sedimentary concentrations of PAHs and PCBs and agricultural gross domestic product (AGDP) per capita relating to DDTs and HCHs. Seasonality and typhoons led to less temporal variations in sedimentary POPs concentrations, whose spatial heterogeneity was remarkably reduced in the post-typhoon period rather than in the pre-typhoon and typhoon periods. The results of this study suggested that fingerprinting legacy POPs in spatial and temporal distributions contributed to identifying the effects of anthropogenic disturbances and climate changes on estuarine sediment quality.

Common chironomids drive the biodiversity–temperature relationship during the Younger Dryas-Holocene transition in a southern Baltic coastal lake

The Younger Dryas-Holocene transition represents a period of significant thermal change, comparable in magnitude to modern warming, yet in a colder context and without the effect of anthropogenic disturbance. This is useful as a reference to tackle how biodiversity is affected by temperature in natural conditions. Here, we addressed the thermal change during this period in a southern Baltic coastal lake (Konarzewo Lake, Poland), as inferred by chironomid remains. We evaluated changes in chironomid communities and used Hill numbers to explore how commonness and rarity underlie biodiversity changes attributable to warming. We found evidence of warming at Konarzewo Lake during the Younger Dryas-Holocene transition, with inferred temperatures in the Younger Dryas period supporting the NW–SE gradient in Younger Dryas summer temperatures across Europe. Chironomid communities drastically changed during the thermal transition. However, Hill numbers showed no response to temperature when rare morphotypes were emphasized (order q = 0) or a weak response when they were balanced with common morphotypes (order q = 1). Hill number of order q = 2, emphasizing the most common morphotypes, consistently increased with temperature across different sample sizes or coverages. This illustrates how common morphotypes, rather than the rare ones, may boost biodiversity facing warming.