Dataset Information

Conversion of tectonic and climatic forcings into records of sediment supply and provenance.

ABSTRACT: Understanding how environmental forcings (e.g., tectonics, climate) are transformed by erosional landscapes into sedimentary signals is a critical component of inverting the stratigraphic record. Previous research has largely focused on sediment supply (Q_s) and grain size as the de facto sedimentary signals of changing forcing mechanisms. We use a numerical model to consider the paired response of sediment provenance (P_v), expressed as fractional sediment load, and Q_s to demonstrate that the same change in environmental forcing may have a different expression in the sedimentary record. While Q_s reflects integrated denudation across an erosional catchment, P_v is controlled by spatially variable erosion that occurs in transient landscapes. P_v from proximal sediment sources increases during upstream knickpoint migration, whereas P_v from distal sediment sources increases when bedrock channels incise to produce lower gradient profiles. Differences between the Q_s and P_v signals relate to distinct geomorphic processes that operate on different time scales and allow for a refined differentiation of the timing and mechanism of forcings than possible via analysis of either signal alone. Future efforts to integrate multiple sedimentary signals may thus yield a richer picture of underlying forcing mechanisms, facilitating efforts to invert the stratigraphic record.

SUBMITTER: Sharman GR

PROVIDER: S-EPMC6411995 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Conversion of tectonic and climatic forcings into records of sediment supply and provenance.

Sharman Glenn R GR Sylvester Zoltan Z Covault Jacob A JA

Scientific reports 20190311 1

Understanding how environmental forcings (e.g., tectonics, climate) are transformed by erosional landscapes into sedimentary signals is a critical component of inverting the stratigraphic record. Previous research has largely focused on sediment supply (Qs) and grain size as the de facto sedimentary signals of changing forcing mechanisms. We use a numerical model to consider the paired response of sediment provenance (Pv), expressed as fractional sediment load, and Qs< ...[more]

PMID: 30858447

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Project description:AimWe test for spatial and climatic patterns of diversification in the Orchidaceae, an angiosperm family characterized by high levels of species diversity and rarity. Globally, does orchid diversity correlate with land area? In Australia, does diversity correlate with herbarium collecting effort, range size, or climate niche breadth? Where are Australia's orchids distributed spatially, in protected areas, and in climate space?LocationGlobal, then Australia.MethodsWe compared orchid diversity with land area for continents and recognized orchid diversity hotspots. Then, we used cleaned herbarium records to compare collecting effort (for Australian Orchidaceae vs. all other plant families, and also among orchid genera). Spatial and climate distributions were mapped to determine orchids' coverage in the protected area network, range sizes, and niche breadths.ResultsGlobally, orchid diversity does not correlate with land area (depauperate regions are the subantarctic: 10 species, and northern North America: 394 species). Australian herbarium records and collecting effort generally reflect orchid species diversity (1,583 spp.), range sizes, and niche breadths. Orchids are restricted to 13% of Australia's landmass with 211 species absent from any protected areas. Species richness is the greatest in three biomes with high general biodiversity: Temperate (especially southwest and southeast Australia), Tropical, and Subtropical (coastal northern Queensland). Absence from the Desert is consistent with our realized climate niche-orchids avoid high temperature/low rainfall environments. Orchids have narrower range sizes than nonorchid species. Highly diverse orchid genera have narrower rainfall breadths than less diverse genera.Main conclusionsHerbarium data are adequate for testing hypotheses about Australian orchids. Distribution is likely driven by environmental factors. In contrast, diversification did not correlate with increases in range size, rainfall, or temperature breadths, suggesting speciation does not occur via invasion and local adaptation to new habitats. Instead, diversification may rely on access to extensive obligate symbioses with mycorrhizae and/or pollinators.

Dataset Information

Conversion of tectonic and climatic forcings into records of sediment supply and provenance.

Publications

Conversion of tectonic and climatic forcings into records of sediment supply and provenance.

Similar Datasets

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