A framework for deriving measures of chronic anthropogenic disturbance: Surrogate, direct, single and multi-metric indices in Brazilian Caatinga

Arnan X., Leal I.R., Tabarelli M., Andrade J.F., Barros M.F., Câmara T., Jamelli D., Knoechelmann C.M., Menezes T.G.C., Menezes A.G.S., Oliveira F.M.P., de Paula A.S., Pereira S.C., Rito K.F., Sfair J.C., Siqueira F.F.S., Souza D.G., Specht M.J., Vieira L.A., Arcoverde G.B., Andersen A.N. (2018) A framework for deriving measures of chronic anthropogenic disturbance: Surrogate, direct, single and multi-metric indices in Brazilian Caatinga. Ecological Indicators. 94: 274-282.
Link
Doi: 10.1016/j.ecolind.2018.07.001

Abstract:

The development of multi-metric indices of chronic anthropogenic disturbance (CAD) from disparate disturbance indicators represents a major challenge for understanding the impacts of CAD on biodiversity, especially in tropical dry areas where livelihoods of local populations are highly dependent on natural resources. We present a conceptual framework for deriving variably integrated, multi-metric measures of CAD from disparate disturbance indicators. Our framework has three steps: (1) identifying the main sources of CAD in the target region, and quantifying them using data of varying levels of spatial and intensity precision; (2) classifying the sources of disturbance into general disturbance pressures, and deriving an index for each; and (3) combining the individual disturbance pressure indices into a fully integrated index that characterizes the overall level of CAD. We apply this framework to Catimbau National Park in the Brazilian Caatinga, using 12 primary data sources to derive disturbance pressure indices relating to livestock, wood extraction and people pressure. The meaningfulness of pressure and overall CAD indices were validated by reference to variation in ant communities. Our analysis revealed notable findings. First, indirect measures from the geographic and socio-ecological context were poorly correlated with direct, field-based measurements, and were therefore of questionable reliability. Second, the three main disturbance pressures were largely independent of each other, which points to complex patterns of resource use by local communities. Third, different weightings of component disturbance pressure indices had little influence on the Global index, making our Global CAD index somewhat insensitive to assessments of the relative importance of different disturbance pressures. Finally, our results caution against a reliance on multivariate ordination to derive integrated indices of disturbance from disparate data sources. Our multi-scale integration of disturbance data can facilitate the analysis of the resource use effects on biodiversity, contributing to effective conservation management and sustainable livelihood development. © 2018 Elsevier Ltd

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Guidelines and considerations for designing field experiments simulating precipitation extremes in forest ecosystems

Asbjornsen H., Campbell J.L., Jennings K.A., Vadeboncoeur M.A., McIntire C., Templer P.H., Phillips R.P., Bauerle T.L., Dietze M.C., Frey S.D., Groffman P.M., Guerrieri R., Hanson P.J., Kelsey E.P., Knapp A.K., McDowell N.G., Meir P., Novick K.A., Ollinger S.V., Pockman W.T., Schaberg P.G., Wullschleger S.D., Smith M.D., Rustad L.E. (2018) Guidelines and considerations for designing field experiments simulating precipitation extremes in forest ecosystems. Methods in Ecology and Evolution. 9: 2310-2325.
Link
Doi: 10.1111/2041-210X.13094

Abstract:

Precipitation regimes are changing in response to climate change, yet understanding of how forest ecosystems respond to extreme droughts and pluvials remains incomplete. As future precipitation extremes will likely fall outside the range of historical variability, precipitation manipulation experiments (PMEs) are critical to advancing knowledge about potential ecosystem responses. However, few PMEs have been conducted in forests compared to short-statured ecosystems, and forest PMEs have unique design requirements and constraints. Moreover, past forest PMEs have lacked coordination, limiting cross-site comparisons. Here, we review and synthesize approaches, challenges, and opportunities for conducting PMEs in forests, with the goal of guiding design decisions, while maximizing the potential for coordination. We reviewed 63 forest PMEs at 70 sites world-wide. Workshops, meetings, and communications with experimentalists were used to generate and build consensus around approaches for addressing the key challenges and enhancing coordination. Past forest PMEs employed a variety of study designs related to treatment level, replication, plot and infrastructure characteristics, and measurement approaches. Important considerations for establishing new forest PMEs include: selecting appropriate treatment levels to reach ecological thresholds; balancing cost, logistical complexity, and effectiveness in infrastructure design; and preventing unintended water subsidies. Response variables in forest PMEs were organized into three broad tiers reflecting increasing complexity and resource intensiveness, with the first tier representing a recommended core set of common measurements. Differences in site conditions combined with unique research questions of experimentalists necessitate careful adaptation of guidelines for forest PMEs to balance local objectives with coordination among experiments. We advocate adoption of a common framework for coordinating forest PME design to enhance cross-site comparability and advance fundamental knowledge about the response and sensitivity of diverse forest ecosystems to precipitation extremes. © 2018 The Authors. Methods in Ecology and Evolution © 2018 British Ecological Society

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Xylem hydraulic safety and construction costs determine tropical tree growth

B. Eller, C., de V. Barros, F., R.L. Bittencourt, P., Rowland, L., Mencuccini, M., S. Oliveira, R. (2018) Xylem hydraulic safety and construction costs determine tropical tree growth. Plant Cell and Environment. 41: 548-562.
Link
Doi: 10.1111/pce.13106

Abstract:

Experimental evidence of the quantitative relationship between the prokaryote ingestion rate and the food vacuole content in mixotrophic phytoflagellates

Ballen-Segura M., Catalan J., Felip M. (2018) Experimental evidence of the quantitative relationship between the prokaryote ingestion rate and the food vacuole content in mixotrophic phytoflagellates. Environmental Microbiology Reports. 10: 704-710.
Link
Doi: 10.1111/1758-2229.12696

Abstract:

The verification that many phytoflagellates ingest prokaryotes has changed the view of the microbial loop in aquatic ecosystems. Still, progress is limited because the phagotrophic activity is difficult to quantify in natural assemblages. Linking the food vacuole content in protist with the ingestion rate of prokaryotes would provide a crucial step forward. In this study, using the catalysed reporter deposition – fluorescence in situ hybridization protocol (CARD-FISH), which allows the visualization of labelled prokaryotes inside protists without relying on incubation procedures, we experimentally relate the food vacuole content of prokaryotes (Vc) to the population-averaged ingestion rates (Ir) estimated using bacteria-size fluorescent microspheres. The two variables relate according to the equation Ir = 7.52 Vc 0.9, which indicates a prokaryote half-life of about 6 min in the protist vacuole. Five mixotrophic flagellate species from natural and culture populations were evaluated seven times during 24 h; they provided a broad range of average vacuole content (0.01 to 2.02 prokaryote protist−1) and ingestion rates (0.18 to 23 prokaryote protist−1 h−1). Consequently, the relationship found can be applied to quantify the mixotrophy activity in a large variety of field and experimental studies. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd

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Assessing ecosystem isoprene emissions by hyperspectral remote sensing

Balzarolo M., Peñuelas J., Filella I., Portillo-Estrada M., Ceulemans R. (2018) Assessing ecosystem isoprene emissions by hyperspectral remote sensing. Remote Sensing. 10: 0-0.
Link
Doi: 10.3390/rs10071086

Abstract:

This study examined the relationship between foliar isoprene emissions, light use efficiency and photochemical reflectance index (PRI) throughout the canopy profile and explored the contribution of xanthophyll cycle pigments versus other carotenoid pigments to the isoprene/PRI relationship. Foliar isoprene emissions within the canopy profile were measured in a high-density poplar plantation in Flanders (Belgium) during the 2016 growing season. The results confirmed that PRI was a promising estimator of isoprene emissions at canopy level. Interestingly, xanthophyll cycle pigments contributed more to isoprene biosynthesis than chlorophyll and drove the isoprene/PRI relationship. The simple independent pigment index and novel defined indices, such as the hyperspectral isoprene index and simple hyperspectral isoprene index, showed promising results and could be suitable estimators of isoprene emissions due to their strong relationship with the xanthophyll pool. © 2018 by the authors.

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Multi-temporal influence of vegetation on soil respiration in a droughtaffected forest

Barba, J., Lloret, F., Poyatos, R., Molowny-Horas, R., Yuste, J.C. (2018) Multi-temporal influence of vegetation on soil respiration in a droughtaffected forest. IForest. 11: 189-198.
Link
Doi: 10.3832/ifor2448-011

Abstract:

Loss of pollinators: evidences, causes and consequences [Pérdida de polinizadores: Evidencias, causas y consecuencias]

Bartomeus I., Bosch J. (2018) Loss of pollinators: evidences, causes and consequences [Pérdida de polinizadores: Evidencias, causas y consecuencias]. Ecosistemas. 27: 1-2.
Link
Doi: 10.7818/ECOS.1542

Abstract:

[No abstract available]

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Trophic transfer from aquatic to terrestrial ecosystems: a test of the biogeochemical niche hypothesis

Bartrons M., Sardans J., Hoekman D., Peñuelas J. (2018) Trophic transfer from aquatic to terrestrial ecosystems: a test of the biogeochemical niche hypothesis. Ecosphere. 9: 0-0.
Link
Doi: 10.1002/ecs2.2338

Abstract:

Matter and energy flow across ecosystem boundaries. Transfers from terrestrial to aquatic ecosystems are frequent and have been widely studied, but the flow of matter from aquatic to terrestrial ecosystems is less known. Large numbers of midges emerge from some lakes in northern Iceland and fly to land. These lakes differ in their levels of eutrophication due to different intensities of geothermal warming and nutrient inputs. In the context of this material transfer from an aquatic to a terrestrial ecosystem, we investigated the relationships between the deposition of midges and the elemental composition and stoichiometry of organisms in low-productivity terrestrial ecosystems. We analyzed several terrestrial food webs in northeastern Iceland with similar food web compositions of terrestrial arthropods but different inputs of midges and analyzed the stoichiometric composition of the different trophic groups. Elemental composition differed among trophic groups and taxa much more than within each trophic group or taxa across the midge deposition gradient. Specifically, the change in N concentration was significant in plants (up to 70% increase in the site with maximum input) but not in predators, which had a more homeostatic elemental composition. These results thus show (1) a significant movement of matter and nutrients from an aquatic to a terrestrial habitat via the emergence of aquatic insects and the deposition of insect carcasses, (2) a larger impact on the elemental composition of plants than arthropods, and (3) support for the biogeochemical niche hypothesis, which predicts that different species should have a specific elemental composition, stoichiometry, and allocation as a consequence of their particular metabolism, physiology, and structure. © 2018 The Authors.

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Citizen Science: A Gateway for Innovation in Disease-Carrying Mosquito Management?

Bartumeus F., Oltra A., Palmer J.R.B. (2018) Citizen Science: A Gateway for Innovation in Disease-Carrying Mosquito Management?. Trends in Parasitology. : 0-0.
Link
Doi: 10.1016/j.pt.2018.04.010

Abstract:

Traditional methods for tracking disease-carrying mosquitoes are hitting budget constraints as the scales over which they must be implemented grow exponentially. Citizen science offers a novel solution to this problem but requires new models of innovation in the public health sector. © 2018 Elsevier Ltd

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Digital long-term topoclimate surfaces of the Pyrenees mountain range for the period 1950–2012

Batalla M., Ninyerola M., Catalan J. (2018) Digital long-term topoclimate surfaces of the Pyrenees mountain range for the period 1950–2012. Geoscience Data Journal. 5: 50-62.
Link
Doi: 10.1002/gdj3.52

Abstract:

Long-term climate data accounting for high-spatial variability and detailed topographic effects are crucial for research and management in complex terrains such as mountain ranges. Here, we introduce the Pyrenean Digital Climate Atlas based on data from around 400 weather stations located across the range during the 1950–2012 period. Average monthly, seasonal, and annual temporal resolutions are provided for 30-m spatial resolution surfaces. Local heterogeneity was considered, integrating meteorological station data, high-quality terrain information (altitude, latitude, distance to the sea, and solar potential radiation) and multivariate regression modelling in a Geographical Information System. Climate surfaces of air temperature (minimum, maximum, and mean) and precipitation were obtained and used to derive maps of bioclimatic interest such as potential evapotranspiration, water availability, and growing degree-days. Metadata are provided in XML standard format (ISO 19139) with all the usual fields and quality indicators for each map, with an RMSE ranging from 0.7 to 1.2°C and 11 to 15 mm for air temperature and precipitation maps respectively. The Atlas is available in GeoTIFF format at the ZENODO repository. Open Practices: This article has earned an Open Data badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at DOI 10.5281/zenodo.1186639. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki. © 2018 The Authors. Geoscience Data Journal published by Royal Meteorological Society and John Wiley & Sons Ltd.

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