Critical Ecological Functions Research Articles

Dynamic evolution trend and driving mechanisms of water conservation in the Yellow River Basin, China

Water conservation (WC) is a critical ecological service function in the Yellow River Basin (YRB). There is currently a lack of detailed exploration of WC development processes and the impact mechanisms of driving factors at spatiotemporal scales in the YRB. By collecting data on DEM, land use, soil, meteorology, reservoirs, and observed discharge, this study established a large-scale WC model using the soil and water assessment tool (SWAT). The abrupt change test, empirical orthogonal function (EOF), wavelet analysis, hierarchical partitioning analysis (HPA), geodetectors, and aridity index were employed to analyze the multi-spatiotemporal characteristics and driving forces of WC calculated using the water balance method. The results are as follows: (1) The average WC among the YRB was 9.11 mm (74.68 × 108 m3) from 1960 to 2020. Pasture and forests contributed to 48.65% and 22.05% of the average annual WC, respectively. (2) WC exhibited four forms: less/more in the YRB, more in the southeast (northwest), and less in the northwest (southeast). (3) Forests and pastures in land use had higher average WC capacity, while Gansu, Shaanxi, and Qinghai ranked in the top three for average WC among the nine provinces. (4) Precipitation was the major driving force affecting WC variations, with the interaction between precipitation and actual evapotranspiration being the most significant. (5) Drought was a significant cause of negative WC. Protecting and managing crucial WC areas was essential for improving the ecological environment. This research elucidates the driving forces of WC in the YRB, providing scientific support for improving regional WC and promoting sustainable development.

Successful conservation and management of kelp forests requires more ambitious use of international law

AbstractKelp forests are the world's most extensive vegetated marine ecosystems. They provide critical ecological functions as well as valuable ecosystem services for human societies. Yet, kelp forests have been largely overlooked in international environmental law. There are no specific treaties focused on kelp, and they have only benefited to a limited extent under existing regimes. This article analyses the treatment of kelp in international environmental law and finds that there are few formally listed sites containing kelp forests and that several treaty regimes could be better utilised for their benefit. The article concludes by outlining more ambitious ways in which international environmental law can better contribute to the conservation and management of kelp forests and other marine ecosystems facing similar futures. This research seeks to shed light on kelp forests and in doing so seeks to contribute to the growing body of multi‐disciplinary literature on kelp and the role that law can play in securing its future.

PROTECTION AND RESTORATION OF BIODIVERSITY AND ECOSYSTEMS OF THE DREVLYANSKY RESERVE

Biodiversity loss is one of the most important environmental issues of our time with far-reaching consequences. Species extinction can disrupt existing ecological linkages and degrade natural communities, potentially leading to their collapse. Declining biodiversity can also destabilise biotic communities, leading to a loss of ecosystem integrity and impairing the ability of the ecosystem to support critical ecological functions. [1-2].

Tracking the long‐term vegetation and soil characteristics of restored mangroves: a case study from Guyana's coast

The global urgency to halt and reverse mangrove loss has led to the implementation of numerous initiatives to protect and restore mangroves and recover critical ecological functions and services. Restoration success is assessed by estimating mangrove survival, while diversity, vegetation structure, and soil characteristics are often overlooked with no long‐term monitoring. Here, we investigated long‐term changes in vegetation and soil characteristics of Avicennia germinans‐dominated stands planted along Guyana's coast between 5 and 11 years old. A chronosequence approach was used to examine changes in vegetation and soil parameters in restored mangrove stands of different ages compared to natural stands of the same ages. Tree height, diameter, and aboveground biomass were inconsistent between restored and natural mangrove stands. Redundancy analysis (RDA) revealed that the soil properties were the important factors influencing both the restored and natural mangrove communities. There were no clear trajectories between the vegetation and soil characteristics with age, possibly due to site‐specific and hydrodynamic environmental factors, such as tidal dynamics, riverine inputs, and climatic variations. While there were some equivalent vegetation and soil characteristics at the end of the first decade after restoration, the restored mangroves may require a longer timespan (approximately 25 years) than the period overserved in our study to be entirely identical to the natural mangroves. This case study from Guyana provides valuable insights into the ecological processes driving mangrove recovery dynamics, growth patterns, and restoration effectiveness and offers reliable data needed to inform future restoration projects.

Outreach, education and knowledge mobilization for effective use of ecosystem-based approaches

Abstract An ecosystem-based approach requires an integration of knowledge systems and collaborative practices. The purpose of outreach, education, and knowledge mobilization is to (1) enhance the environmental literacy of people about the critical ecological and social functions of their ambient ecosystems; and (2) to enhance the production of information, the availability of information across the greatest range of stakeholders, and the transformation of information into experiential knowledge. We focus on these two purposes in the Laurentian Great Lakes of North America, where an ecosystem approach has been a guiding framework for policy and programming for decades. A literature review of outreach, education, and knowledge mobilization is presented with several supporting exemplar case studies and a concluding discussion of interconnected characteristics of outreach, education and knowledge mobilization that include intersectionality, place-based engagement, systems perspective, collaboration, and governance network learning capacity. Recommendations for practice focus on the importance of community engagement, community science, communities of practice, bridging organizations, watershed councils, governmental and other partnerships, financial supports and incentives, access to data, professional development, and policy development.

Impact of urbanization and land use on wetland water quality: A case study in Mengxi town

Wetlands provide critical ecological functions but are facing increasing threats from urbanization. This study assessed the impact of differentiated urban development approaches on wetland water quality in Mengxi town, Hangzhou, China. Water samples were collected from 48 locations in the Wuchang and Hemu wetlands from September 2021 to March 2022, covering different seasons. Parameters including COD, TN, TP, and NH4+-N were analyzed. The results showed the inlet water quality was heavily degraded, with NH4+-N concentrations up to 4.8 mg/L in January. The Hemu wetland showed improved water quality due to dilution effects after convergence of the two inlet rivers. However, NH4+-N and TN remained problematic, with average concentrations of 5.49 mg/L and 5.13 mg/L, exceeding the controlled standards. Statistical analysis identified paddy fields as the dominant contributor of TN (51%) and TP (41%) loads. The area contained 73.5% of total paddy fields obsereverd highest pollution levels. The results highlight the need for targeted agricultural runoff control and land use planning to conserve wetland ecological functions. This study provides important insights on differentiated impacts of urban development models on wetlands in southern China. The findings contribute to effective policy making for wetland water quality protection under rapid urbanization.

Contrasting Altitudinal Patterns and Composition of Soil Bacterial Communities along Stand Types in Larix principis-rupprechtii Forests in Northern China

Bacterial communities inhabiting the soil of mountain ecosystems perform critical ecological functions. Although several studies have reported the altitudinal distribution patterns of bacterial communities in warm-temperate mountain forests, our understanding of typical zonal vegetation dominated by Larix principis-rupprechtii Mayr (abbreviated as larch hereafter) and the understory elevation distribution patterns of soil bacterial communities is still limited. In this study, the Illumina NovaSeq 6000 sequencing platform was used to investigate the changes of surface and subsurface soil bacterial communities along an altitudinal gradient (from 1720 m to 2250 m) in larch forests in northern China. Altitude significantly affected the relative abundance of Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi (bacterial dominant phylum) and Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria (bacterial dominant classes). The diversity of bacterial communities showed a concomitant increase with altitude. The variations in available nitrogen and soil temperature content at different altitudes were the main factors explaining the bacterial community structures in pure stands and mixed stands, respectively. Altitude and the contents of soil organic carbon and soil organic matter were the main factors explaining the dominant phylum (taxonomy). Our results suggest that stand type has a greater effect on the structure and composition of soil bacterial communities than elevation and soil depth, and bacterial communities show divergent patterns along the altitudes, stand types, and soil profiles.

Impact of climate warming on soil microbial communities during the restoration of the inner Mongolian desert steppe.

Grazer exclosure is widely regarded as an effective measure for restoring degraded grasslands, having positive effects on soil microbial diversity. The Intergovernmental Panel on Climate Change (IPCC) predicts that global surface temperatures will increase by 1.5-4.5°C by the end of the 21st century, which may affect restoration practices for degraded grasslands. This inevitability highlights the urgent need to study the effect of temperature on grassland soil microbial communities, given their critical ecological functions. Here, we assessed the effects of heavy grazing (control), grazer exclosure, and grazer exclosure plus warming by 1.5°C on soil microbial community diversity and network properties as well as their relationships to soil physicochemical properties. Our results showed that grazer closure increased soil microbial richness relative to heavy grazing controls. Specifically, bacterial richness increased by 7.9%, fungal richness increased by 20.2%, and the number of fungal network nodes and edges increased without altering network complexity and stability. By contrast, grazer exclosure plus warming decreased bacterial richness by 9.2% and network complexity by 12.4% compared to heavy grazing controls, while increasing fungal network complexity by 25.8%. Grazer exclosure without warming increased soil ammonium nitrogen content, while warming increased soil nitrate nitrogen content. Soil pH and organic carbon were not affected by either exclosure strategy, but nitrate nitrogen was the dominant soil factor explaining changes in bacterial communities. Our findings show that grazer exclosure increases soil microbial diversity which are effective soil restoration measures for degraded desert steppe, but this effect is weakened under warming conditions. Thus, global climate change should be considered when formulating restoration measures for degraded grasslands.

“From Decomposers to Superheroes”: Unleashing the Hidden Powers of Fungi to Save Our Planet

Fungi, often overlooked but omnipresent, hold remarkable potential to address some of the most pressing environmental challenges facing our planet. This article explores the multifaceted roles of fungi, transcending their conventional image as decomposers, and showcases how they emerge as unsung superheroes in the battle for environmental sustainability. From mycorrhizal symbiosis enhancing plant growth to bioremediation activities cleansing polluted environments, fungi play pivotal roles in diverse ecological processes. This article examines the promising applications of fungi in sustainable agriculture, food production, waste decomposition, and the production of biofuels, highlighting their capacity to revolutionise these fields. Furthermore, the medicinal and biotechnological contributions of fungi are also explored, revealing a rich source of bioactive compounds with potential pharmaceutical applications. The role of fungi in the production of various fermented foods and their capacity to combat pests biologically underscore their significance in sustainable food production. Fungi also proves vital in carbon sequestration, erosion control, and soil stabilisation, contributing to global efforts in mitigating climate change and preserving ecosystems. By delving into the world of fungal biodiversity, the paper emphasises the importance of conservation efforts in maintaining ecosystem resilience and preventing the loss of critical ecological functions. This article sheds light on the transformative potential of fungi, urging a paradigm shift in how we perceive and harness these organisms. As our understanding of fungal biology deepens, recognising the vast number of undescribed and unexplored species becomes increasingly important. With their remarkable adaptations and ecological significance, Fungi continue to captivate the scientific community and underscore the need for sustained exploration and conservation efforts in this diverse and understudied kingdom. Recognising fungi as environmental superheroes provides a novel perspective that could inspire innovative solutions for sustainable development and the preservation of our planet's health.

Africa’s ecosystems exhibit a tradeoff between resistance and stability following disturbances

Environmental disturbances may prevent ecosystems from consistently performing their critical ecological functions. Two important properties of ecosystems are their resistance and stability, which respectively reflect their capacities to withstand and recover from disturbance events (e.g. droughts, wildfires, pests, etc). Theory suggests that resistant and stable ecosystems possess opposing characteristics, but this has seldom been established across diverse ecosystem attributes or broad spatial scales. Here, we compare the resistance and stability of >1000 protected area ecosystems in Africa to disturbance-induced losses in primary productivity from 2000 to 2019. We quantitatively evaluated each ecosystem such that following disturbances, an ecosystem is more resistant if it experiences lower-magnitude losses in productivity, and more stable if it returns more rapidly to pre-disturbance productivity levels. To compare the characteristics of resistant versus stable ecosystems, we optimized random forest models that use ecosystem attributes (representing their climatic and environmental conditions, plant and faunal biodiversity, and exposure to human impacts) to predict their resistance and, separately, stability values. We visualized each attribute’s relationship with resistance and stability after accounting for all other attributes in the model framework. Ecosystems that are more resistant to disturbances are less stable, and vice versa. The ecosystem attributes with the most predictive power in our models all exhibit contrasting relationships with resistance versus stability. Notably, highly resistant ecosystems are generally more arid and exhibit high habitat heterogeneity and mammalian biodiversity, while highly stable ecosystems are the opposite. We discuss the underlying mechanisms through which these attributes engender resistance or, conversely, stability. Our findings suggest that resistance and stability are fundamentally opposing phenomena. A balance between the two must be struck if ecosystems are to maintain their identity, structure, and function in the face of environmental change.

Bioaccumulation of emerging persistent organic pollutants in the deep-sea cold seep ecosystems: Evidence from chlorinated paraffin.

Persistent organic pollutants (POPs) are highly toxic and can accumulate in marine organisms, causing nonnegligible harm to the global marine ecosystem. The Cold seep is an essential marine ecosystem with the critical ecological function of maintaining the deep-sea carbon cycle and buffering global climate change. However, the environmental impact of emerging POPs in the deep-sea cold seep ecosystem is unknown. Here, we investigated the potential pollution of chlorinated paraffins (CPs) and their bioaccumulation in the cold seep ecosystem. High concentrations of CPs were detected in the cold seep ecosystems, where CPs bioaccumulated by the keystone species of deep-sea mussels can be released into the surface sediment and vertically migrate into the deeper sediment. Furthermore, more toxic CPs were accumulated from transforming other CPs in the cold seep ecosystem. Our study provides the first evidence that high concentrations of POPs are bioaccumulated by deep-sea mussels in the cold seep ecosystem, causing adverse ecological effects. The discovery of CPs bioaccumulation in the deep-sea cold seep ecosystem is a crucial mechanism affecting deep-sea carbon transport and cycling. This study has important guiding significance for revealing the deep-sea carbon cycle process, addressing global climate change, and making deep-sea ecological and environmental protection policies.

The largest trees in Australia

AbstractLarge old trees have many critical ecological functions. We collated information about Australia's tallest and largest (by circumference) trees from several databases. The 20 tallest trees in Australia are currently all Mountain Ash (Eucalyptus regnans) found primarily in Tasmania. There are also some Mountain Ash trees in Victoria which are over 90 m tall and still increasing in height. The 20 largest (by circumference) trees are distributed throughout four states (NSW, TAS, WA and VIC) with Mountain Ash accounting for more than half of the trees on this list. Making this information available in one location increases its accessibility and allows for priority species and areas for conservation to be more easily identified. Documenting the size and condition of trees, together with their location, will enable them to be revisited and monitored in the future. This practice will allow changes in tree condition, occurring through growth and/or deterioration, to be documented. We trust that by increasing the accessibility of this information, we encourage more people to take an interest in the ecology and conservation of large old trees. This is important given the past and present cultural significance of trees to Australia's First Nations People and the need to preserve this information and appreciation for nature.

Dwindling seagrasses: A multi-temporal analysis on Google Earth Engine

Seagrasses, a unique group of marine flowering plants, profoundly influence the marine environment by providing an array of critical ecological functions. They serve as the foundational habitat for several endangered and charismatic species, including sea cows, sea turtles, and sea horses, and are often referred to as coastal canaries. In comparison to boreal and tropical forests, they have an amazing ability for carbon storage. Despite their long evolutionary history, they are threatened by rapid environmental changes caused by climate change and human activity. Long-term monitoring is required to comprehend the changes in this fragile ecosystem. Conventional field survey methods for collecting long-term data are laborious, time-consuming, and expensive. Hence, this work builds a time-series dataset of the seagrass coverage in the Kalpeni lagoon from 2003 to 2020 by analysing Landsat data on Google Earth Engine. We also evaluated the temporal changes in the seagrass coverage of the study area and studied the influence of selected environmental factors on the seagrass coverage. We observed a negative relationship between sea surface temperature and seagrass coverage. The results revealed a decline in more than 99% of seagrass coverage, indicating an alarming threat to this seagrass ecosystem of the region. With such a drastic shrinkage in the seagrass coverage, the hysteresis must be strong, and the recovery of these meadows may require intensive interventions. By establishing a long-term time series database of seagrass coverage, our study also opens up new avenues for future ecological research on the seagrass meadows.

Monitoring the spatiotemporal change of Dongting Lake wetland by integrating Landsat and MODIS images, from 2001 to 2020

Dongting Lake wetland provides critical ecological functions in the Yangtze River Basin, however its landscape pattern has changed during the past 20 years due to both climate change and the human activities such as the operation of the Three Gorges dam (TGD). Numerous studies have used remote sensing technology to monitor such changes. However, most of studies were conducted at low spatial resolutions (250–1000 m) or low temporal resolutions (few images per year), which can introduce a degree of unreliability as regards the associated conclusions. To thoroughly analyze the spatiotemporal characteristics of Dongting Lake wetland, high spatiotemporal resolution images from 2001 to 2020 have been produced by a modified version of the flexible spatiotemporal data fusion method (cuFSDAF 2.0) developed in this paper. This method is able to retrieve both phenology and land-cover changes both quickly and accurately. In addition, a tailored category by category extraction mapping method (CCEMM) is proposed to reliably classify wetland cover types. The mapping results show that the water area expanded by 66.43 Km2 in the wet season, and shrank by 132.86 Km2 in the dry season, between and including the years, 2001 to 2020. It appeared that the water area in the dry season declined obviously from 2003 to 2010 due to the operation of the TGD and is gradually stabilized after 2010. The reed area increased by 279.59 Km2 and the grass area decreased by 220.46 Km2 in the dry season, from 2001 to 2020. The shrinkage of the water area in the dry season may be one of the main factors driving reeds to occupy the previous grass growth area.

A meta-analysis of ecological functions and economic benefits of co-culture models in paddy fields

The co-culture of rice and poultry/aquatic animals has become a popular strategy to ensure the critical ecological functions and economic benefits of this ecosystem in recent years. Yet, quantitative synthetic effects of co-culture models on ecological functions and economic benefits in paddy fields are poorly understood. This study conducted a meta-analysis of 4707 observations from 224 published papers on the outcomes of co-culture models in paddy fields. On aggregate, co-culture models significantly reduced CH4 emissions by 14.8 % as compared with rice monoculture, but did not affect rice yields, N2O emissions, and greenhouse gas intensity (GHGI). However, significant differences in rice yields, CH4 emissions, GHGI, and economic benefits were observed among various co-culture models and rice-growing regions. Particularly, the co-culture models in East Asia significantly increased rice yields (+2.2 %), reduced CH4 emissions (–22.1 %), and GHGI (–9.4 %). Importantly, co-culture models improved rice grain quality. Furthermore, co-culture models increased soil fertility (7.8–16.2 %), nutrients content in paddy water (26.2–87.0 %), and net ecological and economic benefits (31.7–71.1 %), while decreasing diseases, pests, and weeds (37.0–84.6 %) in paddy fields. Additionally, we suggest that the production of poultry or aquatic animals that alters input and output would increase net income, and it is necessary to develop co-culture models in paddy fields according to regional differences in the agricultural environment. Therefore, our study provides a reference for maximizing ecological and economic benefits of suitable co-culture models in rice-planted areas.

Regenerative capacity of old‐fields on semi‐arid floodplains in the northern Murray–Darling basin

Revegetating abandoned agricultural lands is vital to restoring critical ecological functions and services. Natural regeneration, whereby vegetation regrows via the seeds already present within the landscape, has shown to be an effective approach to restoring large agricultural areas, although more research is required to understand the regenerative capacity of the various seed sources. Here, we investigate the regenerative capacity of old‐fields of semi‐arid floodplains of eastern Australia in a year‐long seedling emergence experiment. We examined the germinable seed banks from three potential propagule sources (soil, leaf litter, and animal scats) collected across 24 field sites, comprising 12 old‐fields and 12 adjacent remnant vegetation patches, distributed across four regions. Soil seed banks stored the most germinable species of the three seed bank types, although these were dominated largely by annual herbaceous species. High abundances of seedlings emerged from scat samples, indicating that native animals, such as kangaroos and emus, play a role in transporting seeds in these landscapes. Finally, leaf litter stored the most germinable propagules of woody species, therefore, representing a vital mechanism for woody vegetation regeneration. There were few differences in emerging seedling assemblages in terms of species richness, abundance or composition between seed banks of old‐fields and adjacent remnant vegetation, suggesting that old‐field seed banks have a high level of resilience. Our findings suggest that these seed banks can make an important contribution to natural regeneration of these old‐fields, but mainly with respect to understory and midstory species, with overstory tree species mostly absent from these seed sources.

Relationships between Organic Matter and Bulk Density in Amazonian Peatland Soils

The carbon pool of Amazonian peatlands is immense and mediates critical ecological functions. As peatlands are dynamic, similar to other wetland systems, modeling of the relationship between organic matter and dry bulk density allows the estimation of the accumulation and/or decomposition of peats. We tested several models: the generalized linear mixed logarithmic, to test depth, and the non-linear logarithmic and power-law models. There is a negative power-law relationship between organic percentage and dry bulk density using peat samples collected in Amazonian peatlands (n = 80). This model is supported by the coefficient of determination (R2) estimates garnered from model fitting, while Akaike Information Criterion (AIC) values further support parsimonious models. We also ran trials of the ideal mixing model with two parameters: k1 representing organic density and k2 representing mineral. The mixture of organic and inorganic components generally falls in accordance with the theory that decreasing k1 trends with increasing k2, although k2 values for these peat samples are negative. The organic k1 coefficient allows us to identify two sites out of the nine investigated, which can be prioritized for their carbon dynamics. The presence of high-density samples, which were not related to depth, indicates clay intrusion in these peatlands. We hope the modeling can explain processes significant to these globally important carbon-rich ecosystems.

Scientists' warning of an imperiled ocean

In 2017, more than 15,000 scientists from 184 countries signed a second warning letter to humanity to caution against our continued wholesale destruction of global ecosystems (Ripple et al., 2017). Here, we reaffirm their message with a similar warning specifically focused on the ocean: humanity must immediately and significantly alter our harmful trajectory in order to avoid irrevocably damaging our oceans in multiple ways that will further affect ocean health for both us and future generations. The ocean is the world's largest realm, housing an astonishing array of biodiversity that provides critical ecological functions that ultimately support life on Earth. In this paper, we outline some of the significant ongoing and imminent activities that degrade ocean health, including destructive fishing practices, oil and natural gas extraction, seabed mining, coastal development, shipping, pollution, and greenhouse-gas emissions. We end by offering potential avenues to mitigate these impacts, including the cessation of particularly harmful activities, restoration of damaged habitats, strong protection of key and representative ecosystems, reduction in waste and emissions, and global policy shifts that prioritize ecosystem health.

Assessing Occurrence and Biological Consequences of Contaminants of Emerging Concern on Oceanic Islands

Freshwater streams on oceanic islands serve critical ecological and economic functions. However, these are underrepresented in assessments of pollution from contaminants of emerging concern (CEC). Furthermore, freshwater streams and their endemic fauna often have characteristics that are distinct from those of continental streams and model species, calling extrapolations from studies of such systems into question for island streams. In the current study, we assessed the presence of CEC across three sampling events and five freshwater streams on the Island of Hawai’i. We also exposed juveniles of the native fish species Sicyopterus stimpsoni to a mixture of commonly co-occurring CEC for 96 h in static renewal experiments, testing for impacts of CEC in two ecologically relevant assays of functional performance. CEC from multiple sources were ubiquitous in Hawaiian streams, including human-use pharmaceuticals, agricultural herbicides, and industrial runoff. Concentrations of CEC were comparable to published studies from continental streams, exceeding total concentrations of 1000 ng/L for the eight quantified CEC in four samples, and approaching 2500 ng/L in one sample. Effects on exposed fish were subtle and limited to treatments with higher CEC concentrations but indicated potential impacts of CEC on locomotor performance. These results indicate that Hawaiian streams follow a global trend of widespread freshwater pollution by CEC that are accompanied by subtle effects on native fish species and highlight the need for the inclusion of endemic species and ecologically relevant assays when assessing the effects of contaminants in island habitats.

Divergent change patterns observed in hydrological fluxes entering China's two largest lakes

Large lakes are key components of hydrological processes and have critical ecological and economic functions. Streamflow and riverine sediment loads exported from tributary rivers to lakes provide inputs of water and nutrients and greatly impact the health of lacustrine ecosystems. Understanding the spatiotemporal patterns of water and sediment transport dynamics within the basins of large lakes is therefore required for informed management of their resources. In particular, the hydrological processes of large lake basins in western China were not fully explored yet. This study investigated changes in runoff and sediment fluxes entering the two largest lakes in China (Qinghai Lake and Poyang Lake) over the past half century. Our results showed that the regional trends of the two lake basins have changed in divergent way. The patterns of change of streamflow and sediment transport—including the trends, periodicity, and transition points as well as the relationship between streamflow and sediment flux—were quite different. The results obtained by a Sediment Identity method revealed that increases of the precipitation and runoff coefficient controlled the observed increase of streamflow and sediment flux within the Qinghai Lake basin, whereas the decrease of the sediment flux entering Poyang Lake was caused mainly by a reduction in sediment concentration. Climate change was the dominant driver influencing the recent increases in surface water resources and sediment load in the Qinghai Lake basin as well as the long-term fluctuations of streamflow within the Poyang Lake basin. In contrast, the observed abrupt reduction in total sediment flux entering Poyang Lake was due mainly to declining sediment discharge from the Gan River; this decrease is attributed primarily to human activities, especially reservoir construction and soil conservation practices. Overall, this study discovers the divergent change patterns when investigating hydrological processes, and highlights the importance of developing policies for managing soil and water resources within large lake basins to the northwest and southeast of the Hu Line. Management policies should consider the tremendous differences in geography, climate, and population across China.