scholarly journals Human Land-Use Practices Lead to Global Long-Term Increases in Photosynthetic Capacity

2014 ◽  
Vol 6 (6) ◽  
pp. 5717-5731 ◽  
Author(s):  
Thomas Mueller ◽  
Gunnar Dressler ◽  
Compton Tucker ◽  
Jorge Pinzon ◽  
Peter Leimgruber ◽  
...  
2020 ◽  
Author(s):  
Konsta Happonen ◽  
Lauralotta Muurinen ◽  
Risto Virtanen ◽  
Eero Kaakinen ◽  
John-Arvid Grytnes ◽  
...  

AbstractAimLand use is the foremost cause of global biodiversity decline, but species do not respond equally to land-use practices. Instead, responses are mediated by species traits, but long-term data on the trait-mediated effects of land-use on communities is scarce. Here we study how forest understory communities have been affected by common land-use practices during 4–5 decades, and whether changes in diversity are related to changes in functional composition.LocationFinlandTime period1968–2019Major taxa studiedVascular plantsMethodsWe resurveyed 245 semi-permanent vegetation plots in boreal herb-rich forest understories, and used path analysis to relate changes in diversity, species composition, average plant size, and leaf economic traits to reindeer husbandry, forest management intensity, and changes in canopy cover and canopy traits.ResultsForestry affected understories indirectly by increasing canopy shading, which increased understory SLA and decreased LDMC over the study period. Intensive management also decreased species richness and increased turnover. In areas with reindeer husbandry, reindeer density had increased along with understory evenness and diversity. Areas with reindeer husbandry also had lower temporal community turnover. Plant height had increased in areas without reindeer, but this trend was suppressed or even reversed within the reindeer herding area.Main conclusionsFunctional traits are useful in connecting vegetation changes to the mechanisms that drive them. Forest management causes directional selection on light-interception traits by altering shade. Reindeer husbandry seems to buffer forest understory communities against compositional changes by altering selection on whole-plant traits such as size. These trait-dependent selection effects could inform which species benefit and which suffer from different types of land use, and point to the potential usefulness of large herbivores as tools for managing vegetation changes under global change.


2021 ◽  
Vol 118 (17) ◽  
pp. e2023483118 ◽  
Author(s):  
Erle C. Ellis ◽  
Nicolas Gauthier ◽  
Kees Klein Goldewijk ◽  
Rebecca Bliege Bird ◽  
Nicole Boivin ◽  
...  

Archaeological and paleoecological evidence shows that by 10,000 BCE, all human societies employed varying degrees of ecologically transformative land use practices, including burning, hunting, species propagation, domestication, cultivation, and others that have left long-term legacies across the terrestrial biosphere. Yet, a lingering paradigm among natural scientists, conservationists, and policymakers is that human transformation of terrestrial nature is mostly recent and inherently destructive. Here, we use the most up-to-date, spatially explicit global reconstruction of historical human populations and land use to show that this paradigm is likely wrong. Even 12,000 y ago, nearly three quarters of Earth’s land was inhabited and therefore shaped by human societies, including more than 95% of temperate and 90% of tropical woodlands. Lands now characterized as “natural,” “intact,” and “wild” generally exhibit long histories of use, as do protected areas and Indigenous lands, and current global patterns of vertebrate species richness and key biodiversity areas are more strongly associated with past patterns of land use than with present ones in regional landscapes now characterized as natural. The current biodiversity crisis can seldom be explained by the loss of uninhabited wildlands, resulting instead from the appropriation, colonization, and intensifying use of the biodiverse cultural landscapes long shaped and sustained by prior societies. Recognizing this deep cultural connection with biodiversity will therefore be essential to resolve the crisis.


Water SA ◽  
2021 ◽  
Vol 47 (3 July) ◽  
Author(s):  
S Hugo ◽  
OLF Weyl

A South African inland fisheries policy will depend on a reliable long-term supply of social-ecological data covering freshwater fisheries at a broad geographic scale. Approaches to systematic planning of research and monitoring are demonstrated herein, based on a fishery-independent gillnet dataset covering 44 dams, and geographic information system maps of monthly and annual climate variables, human land use, and road access in a 5 km zone around 442 dams. Generalised linear mixed models were used to determine the covariates of gillnet catch per unit effort. Such covariates are required for a model-based process to select a subset of state-owned dams for a long-term fishery survey programme. The models indicated a monthly climate influence on catch per unit effort and climatic drivers of fish species distributions. However, unexplained variation is overwhelming and precludes a model-based survey design process. Non-hierarchical clustering of 442 dams was then done based on annual climate and human land use variables around dams. The resulting clusters of dams with shared climate and land use characteristics indicates the types of dams that should be selected for monitoring to represent the full range of climate and land use characteristics. Surrounding land use could indicate the socioeconomic characteristics of fisheries, for example, dams that may support subsistence-based communities that require increased research effort. Finally, although primary catchments could be useful for organising national-scale management, land use cover in the 5 km zone around dams varied widely within the respective primary catchments. Beyond these proposed approaches to plan research, this study also reveals various data deficiencies and recommends additional future studies on other possible methods for systematic research planning.


Groundwater provides over 30% of developed supplies of potable water in Britain. The outcrops of the important aquifers form extensive tracts of agricultural land. Groundwater resources largely originate as rainfall that infiltrates this land. During the 1970s, growing concern about rising, or elevated, groundwater nitrate concentrations, in relation to current drinking water standards, stimulated a major national research effort on the extent of diffuse pollution resulting from agricultural land-use practices. The results presented derive from intensive and continuing studies of a number of small groundwater catchments in eastern England. It is in this predominantly arable region that the groundwater nitrate problem is most widespread and severe. The distribution of nitrate in the unsaturated and saturated zones of the aquifers concerned is summarized. These data have important implications for the water-supply industry, but their interpretation is discussed primarily in relation to what can be deduced about both the recent and long-term histories of leaching from the more permeable agricultural soils.


2011 ◽  
Vol 77 ◽  
pp. 279-319
Author(s):  
Clive Waddington ◽  
Peter Marshall ◽  
David G. Passmore

The Tweed Valley and its tributaries, and particularly the Milfield Basin in north Northumberland, is an area of strategic significance in the geography of the British Isles and it hosts a rich and varied multi-period archaeological and palaeoenvironmental record. This paper summarises some of the key findings for the Neolithic resulting from a long-term and in-depth landscape research project and provides a new chronological sequence for the Neolithic of the region.Attention is drawn to the discovery of what appears to be a new type of Neolithic structure associated with settlement activity hitherto unrecognised in Britain: post-built timber buildings based on a triangular arrangement of timbers. The paper then turns to a consideration of subsistence and land-use practices and the evidence for cereal agriculture from the immediate outset of the Neolithic in the region. Since 1999 many more radiocarbon measurements have become available for Neolithic activity in the area and, together with those obtained before 1999, have been recalibrated and subjected to Bayesian modelling to produce more precise estimates for Neolithic activity. Important findings include the provision of a more robust estimate for dating the onset of the Neolithic in the region, as well as establishing a chronological framework for the Neolithic–Beaker period ceramic sequence. It also reveals that the current dating available for the henge monuments indicates that this ritual complex most likely dates to the Beaker period and not to the Neolithic proper as they do in some other parts of Britain. Truly ‘Neolithic’ ceremonial monuments in the Milfield Basin remain elusive and few of the potential sites that have so far been identified have yet to be tested by excavation and scientific dating. A clear zoning of rock art is apparent, with hundreds of sites all clustered on the Fellsandstone escarpment, while a variety of Neolithic burial types is attested suggesting the region formed a meeting ground for different cultural influences.


age ◽  
2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Aditi Sengupta ◽  
Janani Hariharan ◽  
Parwinder S. Grewal ◽  
Warren A. Dick

2021 ◽  
Vol 13 (15) ◽  
pp. 8567
Author(s):  
Jillian A. Swift ◽  
Patrick V. Kirch ◽  
Jana Ilgner ◽  
Samantha Brown ◽  
Mary Lucas ◽  
...  

Tikopia Island, a small and relatively isolated Polynesian Outlier in the Southeast Solomon Islands, supports a remarkably dense human population with minimal external support. Examining long-term trends in human land use on Tikopia through archaeological datasets spanning nearly 3000 years presents an opportunity to investigate pathways to long-term sustainability in a tropical island setting. Here, we trace nutrient dynamics across Tikopia’s three pre-European contact phases (Kiki, Sinapupu, Tuakamali) via stable carbon and nitrogen isotope analysis of commensal Pacific rat (Rattus exulans) and domestic pig (Sus scrofa) bone and tooth dentine collagen. Our results show a decline in δ15N values from the Kiki (c. 800 BC-AD 100) to Sinapupu (c. AD 100–1200) phases, consistent with long-term commensal isotope trends observed on other Polynesian islands. However, increased δ15N coupled with lower δ13C values in the Tuakamali Phase (c. AD 1200–1800) point to a later nutrient rejuvenation, likely tied to dramatic transformations in agriculture and land use at the Sinapupu-Tuakamali transition. This study offers new, quantifiable evidence for deep-time land and resource management decisions on Tikopia and subsequent impacts on island nutrient status and long-term sustainability.


2018 ◽  
Vol 26 (1) ◽  
pp. 8-9 ◽  
Author(s):  
Kathleen D Morrison ◽  
◽  
E Hammer ◽  
L Popova ◽  
M Madella ◽  
...  

2011 ◽  
Vol 8 (3) ◽  
pp. 4391-4419 ◽  
Author(s):  
W. Clymans ◽  
E. Struyf ◽  
G. Govers ◽  
F. Vandevenne ◽  
D. J. Conley

Abstract. Human land use changes directly affect silica (Si) mobilisation and Si storage in terrestrial ecosystems and influence Si export from the continents, although the magnitudes of the impact are unknown. Yet biogenic silica (BSi) in soils is an understudied aspect. We have quantified and compared total biogenic (PSia) and easily soluble (PSie) Si pools at four sites along a gradient of disturbance in southern Sweden. An estimate of the magnitude of change in temperate continental BSi pools due to human disturbance is provided. Land use clearly affects BSi pools and their distribution. Total PSia and PSie for a continuous forested site at Siggaboda Nature Reserve (66 900 ± 22 800 kg SiO2 ha−1 and 952 ± 16 kg SiO2 ha−1) are significantly higher than disturbed land use types from the Råshult Culture Reserve including arable land (28 800 ± 7200 kg SiO2 ha−1 and 239 ± 91 kg SiO2 ha−1), pasture sites (27 300 ± 5980 kg SiO2 ha−1 and 370 ± 129 kg SiO2 ha−1) and grazed forest (23 600 ± 6370 kg SiO2 ha−1 and 346 ± 123 kg SiO2 ha−1). Vertical PSia and PSie profiles show significant (p<0.05) variation among the sites. These differences in size and distribution are interpreted as the long-term effect of reduced BSi replenishment and increased mobilisation of the PSia in disturbed soils. In temperate regions, total PSia showed a 10 % decline since agricultural development (3000BCE). Recent agricultural expansion (after 1700CE) has resulted in an average export of 1.1 ± 0.8 Tmol Si yr−1, leading to an annual contribution of ca. 20 % to the global land-ocean Si flux carried by rivers. Human activities clearly exert a long-term influence on Si cycling in soils and contribute significantly to the land-ocean Si flux.


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