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Critical Zone Science (CZS) represents a powerful confluence of research agendas, tools, and techniques for examining the complex interactions between biotic and abiotic factors located at the interface of the Earth's surface and shallow subsurface. Earth's Critical Zone houses and sustains terrestrial life, and its interacting subsystems drive macroecological patterns and processes at a variety of spatial scales. Despite the analytical power of CZS to understand and characterize complicated rate-dependent processes, CZS has done less to capture the effects of disturbance and anthropogenic influences on Critical Zone processes, although some Critical Zone Observatories focus on disturbance and regeneration. Methodological approaches from biogeography and ecology show promise for providing Critical Zone researchers with tools for incorporating the effects of ecological and anthropogenic disturbance into fine-grained studies of important Earth processes. Similarly, mechanistic insights from CZS can inform biogeographical and ecological interpretations of pattern and process that operate over extensive spatial and temporal scales. In this paper, we illustrate the potential for productive nexus opportunities between CZS, biogeography, and ecology through use of an integrated model of energy and mass flow through various subsystems of the Earth's Critical Zone. As human-induced effects on biotic and abiotic components of global ecosystems accelerate in the Anthropocene, we argue that the long temporal and broad spatial scales traditionally studied in biogeography can be constructively combined with the quantifiable processes of energy and mass transfer through the Critical Zone to answer pressing questions about future trajectories of land cover change, post-disturbance recovery, climate change impacts, and urban hydrology and ecology. [ABSTRACT FROM AUTHOR]

This paper examines the mid- to late-Holocene (c. 6850-1160 cal. yr BP) environmental history of Sierra de Gádor in southern Spain. The local vegetation dynamics are reconstructed through the palaeoecological record obtained from a lacustrine deposit situated at 1530 m. Various hypotheses are considered to explain the vegetation dynamics apparent in the palaeoecological evidence, including climatic change, fire occurrence and human activity. Although the vegetation in this region is sensitive to climatic change, threshold events driven by ecological factors are also apparent. Climatic events include a thermo-mesophytic optimum with abundance of deciduous trees and maximum lake water level found from c. 6850 to 5500 cal. yr BP. In contrast, changes in the frequency of major fire episodes appear to have shaped interspecific relationships and vegetation change, especially from c. 4200 cal. yr BP onwards. Biotic properties of the ecosystem such as the inertia of established tree populations, interconnected with competition adjustments, appear also to have played a role. Over the last two millennia, overgrazing, combined with natural and/or human-set fires, appears to have pushed mountain forests over a threshold leading to the spread of grassland, thorny scrub, junipers and nitrophilous communities. [ABSTRACT FROM AUTHOR]

A sediment core from Taibai Lake, a shallow and eutrophic lake (SE China), was analysed for chironomids to track environmental changes in the lake. Nutrient dynamics over the past 1400 years were traced based on subfossil records and a regional chironomid-inferred total phosphorus (CI-TP) transfer function. Between ad 600 and 1370, the coexistence of several macrophyte-related taxa such as Dicrotendipes, Paratanytarsus and Endochironomus reflected a clear-water state with flourishing plants, and total phosphorus (TP) reconstructions ranged from 40 to 60 µg/L. For the time span from ad 1370 to 1650, the prevalence of Paratanytarsus penicillatus-type indicated a slight decline of TP to lower than 50 µg/L, but CI-TP increased to previous levels between ad 1650 and 1940. Since the 1950s, Chironomus plumosus-type dominated the chironomid community, which illustrated that the lake suffered from high nutrient loadings and CI-TP increased from 80 to 140 µg/L. The results suggest that 50–60 µg/L of TP concentration is the reference condition for Taibai Lake, and ~80–110 µg/L might be considered as the nutrient threshold range between the plant-dominated and algal-dominated status. Variance partitioning analysis (VPA) was used to determine the relative influence of climate and human factors on the lake ecosystem. The analyses revealed that long-term climate change appeared to be the main determinant regulating the chironomid assemblages; however, the impact of human activities on the aquatic ecosystem prevailed over that of climate factors since the 1950s. This study improves our understanding of complex trajectories of aquatic ecosystem development at centennial to millennial timescales, which are influenced by both anthropogenic and climatic factors in a densely populated region. The main finding also provides reference for sustainable management in this lake and other analogous floodplain lakes. [ABSTRACT FROM AUTHOR]