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Agricultural expansion drives biodiversity loss globally, but impact assessments are biased towards recent time periods. This can lead to a gross underestimation of species declines in response to habitat loss, especially when species declines are gradual and occur over long time periods. Using Cold War spy satellite images (Corona), we show that a grassland keystone species, the bobak marmot ( Marmota bobak ), continues to respond to agricultural expansion that happened more than 50 years ago. Although burrow densities of the bobak marmot today are highest in croplands, densities declined most strongly in areas that were persistently used as croplands since the 1960s. This response to historical agricultural conversion spans roughly eight marmot generations and suggests the longest recorded response of a mammal species to agricultural expansion. We also found evidence for remarkable philopatry: nearly half of all burrows retained their exact location since the 1960s, and this was most pronounced in grasslands. Our results stress the need for farsighted decisions, because contemporary land management will affect biodiversity decades into the future. Finally, our work pioneers the use of Corona historical Cold War spy satellite imagery for ecology. This vastly underused global remote sensing resource provides a unique opportunity to expand the time horizon of broad-scale ecological studies.

Land cover change is the largest direct driver of global biodiversity loss but often the relationships between habitats and species occurrence are unknown. The conservation community requires tools to assess variation in biodiversity related to land cover for maximizing return on investment. Our objectives were to 1) develop a biodiversity mapping and assessment tool at a fine spatial scale for terrestrial vertebrates, and 2) test how much biodiversity is conserved by retaining natural habitats within agricultural landscapes. We built species distribution models for amphibians, birds, mammals, and reptiles (329 species, > 1.2 million observations) within Prairie Canada. Predicted biodiversity within 805 m × 805 m sites ranged from 0 to 238 species (66 ± 0.1). The proportion of annual cropland at a site had the largest negative effect on biodiversity among predictors. Using simulations of land cover change, we predicted that conserving 20 % of natural habitats would conserve an average of 26.5 % of maximum species richness in fields with annual cropland and 74.3 % of maximum species richness in fields with tame grass (perennial cropland). Our tool predicted that fields with conservation easements (n = 312) had more species (114 ± 2) and natural habitat (48 ± 1 %) compared to nearby unprotected sites (82 ± 3 species; 32 ± 2 % natural habitat). Our results highlight the importance of retaining natural habitats, including wetlands, grasslands, and forests within farms to support biodiversity. In addition, our predictions can be used to target areas for conserving and restoring habitats. [ABSTRACT FROM AUTHOR]

Anthropic actions have motivated pieces of research on the impacted naturally poor soils of the Brazilian Amazon, requiring the use of diagnostic attributes that are increasingly specific to each environmental change. The use of magnetic proxies inherent in the soil may be the key to understanding the changes that occur in the soil and the environment. Therefore, this study aimed to characterize the physical, chemical and mineralogical properties of Alisols, in addition to determining the intensity and origin of the magnetic signal for future calibrations as an environmental proxy for monitoring soil fertility. One natural and three cultivated Alisols were sampled using systematic meshes in three layers: 0–5, 5–10 and 10–20 cm. The natural Alisol is a tropical forest and the agricultural ones refer to the cultivation of annatto, cupuaçu and guarana. A total of 192 samples/area were submitted to physical, chemical, mineralogical and magnetic susceptibility (MS) analysis. MS measured at low and high frequency and converted to specific mass (χ lf and χ hf), then descriptive, univariate and multivariate statistical analyzes were applied to the results. The conversion of the physically good and chemically poor and acidic natural Alisols to agricultural crops, caused an increase in the density and amplitude of the pH in water and Al3+ of the soil, plus a reduction in macroporosity, gravimetric humidity, available phosphorus and iron oxalate contents, and the incorporation of organic carbon in depth. All Alisols showed low χ lf and χ hf. However, χ lf values decreased in depth for cultivated Alisols (0.53–0.26 x 10−6 m3 kg−1), whereas, for natural Alisol, these values tended to increase towards the subsurface (0.21–0.23 x 10−6 m3 kg−1). Nevertheless, the value of χ lf and χ hf were highly representative within the cultivation areas, which was characterized as a suitable proxy to monitor the fertility of the Alisols in the Amazon region. • Converting natural Alisols to crops changes their physical and chemical attributes. • Alisols from Amazonas have low χ lf and χ hf. • Cultivated Alisols have χ lf and χ hf with behavior opposite to the natural one. • χ lf and χ hf are potential proxies to monitor small variations in Alisols attributes. [ABSTRACT FROM AUTHOR]

Abstract: Iron cycling in wetlands is important because it plays an important role in interactions among wetland soils/sediments, plants and microorganisms. The seasonal variation of iron (Fe) distributed in two freshwater peatland ecosystems dominated by Calamagrostis angustifolia (CA) and Carex lasiocarpa (CL), was observed in Sanjiang Plain of Northeast China. The compartmentalization of the Fe cycle including storage in the atmosphere, litter, soil, and above- and below ground plant material was determined. The results showed that the Fe input from rain was 0.06gm−2 a−1, and the total Fe mass in the peatland ecosystem was 5.18×103 for CA and 1.40×103 gm−2 for CL. The major Fe pools were soils (98.6% and 97.1% for CA and CL, respectively). The Fe fluxes between each compartment resulted in the increase of the belowground Fe pool and decrease of the litter Fe pool currently both for CA and CL. CL has greater uptake coefficient (0.024) and cycle coefficient (0.034), but smaller use coefficient (0.58) than that of CA (0.02, 0.006, and 0.77, respectively). Peatland conversion for agriculture affected the former natural Fe cycle processes and mass balance to a certain extent in long term, because the Fe assimilated by soybean and rice are less than that of CA and CL, and cannot return to soils from harvesting. Drainage and ditch excavation for agricultural conversion caused considerable Fe loss via aqueous movement, so that Fe was likely lost and transported downstream by these ditch networks. [Copyright &y& Elsevier]

gricultural drainage is thought to alter greenhouse gas emissions from temperate peatlands, with CH emissions reduced in favor of greater CO losses. Attention has largely focussed on C trace gases, and less is known about the impacts of agricultural conversion on NO or global warming potential. We report greenhouse gas fluxes (CH, CO, NO) from a drained peatland in the Sacramento-San Joaquin River Delta, California, USA currently managed as a rangeland (that is, pasture). This ecosystem was a net source of CH (25.8 ± 1.4 mg CH-C m d) and NO (6.4 ± 0.4 mg NO-N m d). Methane fluxes were comparable to those of other managed temperate peatlands, whereas NO fluxes were very high; equivalent to fluxes from heavily fertilized agroecosystems and tropical forests. Ecosystem scale CH fluxes were driven by 'hotspots' (drainage ditches) that accounted for less than 5% of the land area but more than 84% of emissions. Methane fluxes were unresponsive to seasonal fluctuations in climate and showed minimal temporal variability. Nitrous oxide fluxes were more homogeneously distributed throughout the landscape and responded to fluctuations in environmental variables, especially soil moisture. Elevated CH and NO fluxes contributed to a high overall ecosystem global warming potential (531 g CO-C equivalents m y), with non-CO trace gas fluxes offsetting the atmospheric 'cooling' effects of photoassimilation. These data suggest that managed Delta peatlands are potentially large regional sources of greenhouse gases, with spatial heterogeneity in soil moisture modulating the relative importance of each gas for ecosystem global warming potential. [ABSTRACT FROM AUTHOR]

The likely Reducing Emissions from Deforestation and Degradation (REDD+) mechanism includes strategies for the enhancement of forest carbon stocks. Recent concerns have been expressed that such enhancement, or restoration, of forest carbon could be counterproductive to biodiversity conservation, because forests are managed as 'carbon farms' with the application of intensive silvicultural management that could homogenize diverse degraded rainforests. Restoration increases regeneration rates in degraded forest compared to naturally regenerating forest, and thus could yield significant financial returns for carbon sequestered. Here, we argue that such forest restoration projects are, in fact, likely to provide a number of benefits to biodiversity conservation including the retention of biodiversity, the prevention of forest conversion to agriculture, and employment opportunities for poor local communities. As with other forms of forest-based carbon offsets, there are possible moral hazard and leakage problems with restoration. However, due to the multiple benefits, we urge that enhancement of forest carbon stocks be detailed as a major component in the future negotiations of REDD+. [ABSTRACT FROM AUTHOR]