DOI: 10.5061/dryad.j6q573nn3
title: Chronic anthropogenic disturbance mediates the biodiversity-productivity relationship across stand ages in a large temperate forest region

description: Temperate forests, especially those in the densely populated regions of
 the world, are experiencing increasing levels of habitat degradation and
 biological impoverishment due to subtle but pervasive chronic
 anthropogenic disturbances including frequent and continuous grazing and
 extraction of non-timber forest products. However, the effects of these
 subtle, chronic disturbances on the biodiversity-productivity relationship
 have rarely been examined especially in forests at different development
 stages. Accordingly, this study explores how chronic anthropogenic
 disturbance affects the relationship between tree species diversity and
 forest productivity at different stand development stages in a large
 temperate forest region.   We used the human footprint index as a
 proxy for chronic human disturbance. Hierarchical Bayesian models were
 employed to assess the effects of chronic human disturbance on the
 relationship between tree diversity and forest productivity across
 different stand age. Several measures of diversity were employed,
 including taxonomic, functional and phylogenetic diversity.  
 Forest productivity consistently increased with taxonomic, functional and
 phylogenetic biodiversity; these biodiversity facets were the main drivers
 of forest productivity compared to stand age, chronic human disturbance,
 and climate. However, the magnitude at which productivity increases with
 the increments of taxonomic and functional diversity diminishes with the
 increasing chronic disturbance, especially in younger stands. The effects
 of phylogenetic diversity on productivity did not vary with chronic
 disturbance, regardless of stand age.   Synthesis and
 applications: Chronic human disturbance in a large temperate forest region
 reduces the increase in community productivity due to different facets of
 biodiversity, especially in young forests. The evidence suggests that the
 mitigation of chronic human disturbance and the conservation of
 biodiversity will be effective in sustaining essential ecosystem
 functions.
description: The study area (<em>c</em>. 700,000
 km<sup>2</sup>) is a large temperate forest region situated in
 northeastern China (latitude 39°42’48”-53°19’21” N, longitude
 119°48’12”-134°01’01” E) where coniferous and broadleaved forests occur.
 The climate is temperate continental with significant temperature
 seasonality (average annual temperature ranging from -5.1 to 8.8°C) and
 precipitation seasonality (rainfall ranging from 404 to 985 mm).
 Altogether 379 circular field plots, each measuring 0.1 ha, were
 systematically established in 2017, across the study region. The minimum
 and average distance between plots is 10 km and 19 km, respectively. All
 individual trees with a diameter greater than 5 cm at breast height (DBH)
 were tagged, mapped, and recorded. Each plot was equally divided into ten
 subplots of 0.01 ha. Wood cores were extracted from the northern side of
 each tree at breast height using increment borers (5.15 mm) in 2017. The
 collected wood core samples were subjected to analysis to directly
 ascertain past diameters by subtracting the radial increments of each tree
 for the previous five-year interval (from 2012 to 2017). We calculated the
 biomass accumulation of all trees with a DBH &gt; 5 cm based on the
 available species-specific allometric equations in the various regions.
 Then, the biomass of each subplot was estimated for the years 2012 and
 2017. Forest biomass productivity (BP) of each subplot was quantified as
 biomass increments per hectare from 2012 to 2017.
description: # Chronic anthropogenic disturbance mediates the biodiversity-productivity
 relationship across stand ages in a large temperate forest region * File
 containing data of the biotic variables and environmental variables
 examined for local communities (0.01ha) and plots (0.1ha). ## Data and
 File Overview ## Summary Metrics * File count: 1 * File formats: .csv ##
 Naming Conventions * File naming scheme: files with the "local
 communities" denote 3614 local communities included in the study. ##
 Table of Contents * local communities.csv ## File/Folder Details ##
 Details for: local communities.csv * Description: one file containing the
 biotic variables and environmental variables (scaled) for 379 plots and
 3614 local communities included in the study. * Format(s): .csv *
 Dimensions: 3614 rows x 15 columns * Variables: * plot: 379 plots * local
 communities: 3614 local communities * BP: the biomass productivity within
 a given local community; unit: Mg ha-1 yr-1 * SR: the tree species
 richness within a given local community; unit: unitless * 1D: Hill numbers
 as alternative taxonomic diversity measures within a given local
 community; unit: unitless * 2D: Hill numbers as alternative taxonomic
 diversity measures within a given local community; unit: unitless * FPD:
 phylogenetic diversity within a given local community; unit: unitless *
 FDSLA: functional diversity of specific leaf area within a given local
 community; unit: unitless * FDLA: functional diversity of leaf area within
 a given local community; unit: unitless * FDWD: functional diversity of
 wood density within a given local community; unit: unitless * FDN:
 functional diversity of leaf nitrogen concentration within a given local
 community; unit: unitless * AGE: stand age within a given plot; unit: year
 * H: human footprint within a given plot; unit: unitless * TS: temperature
 seasonality within a given plot; unit: unitless * PS: precipitation
 seasonality within a given plot; unit: unitless * Description of the
 variables for local communities (0.01ha) and plots (0.1ha): * Forest
 biomass productivity (BP) of each subplot was quantified as biomass
 increments per hectare from 2012 to 2017. * Taxonomic diversity was
 quantified as the tree species richness (SR). In addition to SR, we also
 studied Hill numbers (1D and 2D) as alternative taxonomic diversity
 measures. 1D was calculated as the exponential of the familiar Shannon
 entropy. 2D was calculated as the inverse of the Gini-Simpson index. *
 Functional diversity was quantified as the functional dispersion of single
 trait values using leaf area, specific leaf area, leaf nitrogen
 concentration, and wood density. * Phylogenetic diversity was quantified
 as Faith's phylogenetic diversity based on evolutionary distance. *
 The human footprint index (H) was used as a proxy for chronic
 anthropogenic disturbance. The human footprint index was extracted from
 the global human footprint map with a 1 km2 resolution. A human footprint
 map was constructed based on eight surveyed human pressure indicators
 including (1) the extent of built-up environments, (2) human population
 density, (3) electricity infrastructure, (4) crop lands, (5) pasture
 lands, (6) roads, (7) railways, and (8) navigable waterways. * The stand
 age (AGE) is a proxy for the approximate number of years that have elapsed
 since the cessation of prior deforestation and the year when our
 measurements were conducted. Stand age was determined through tree ring
 analysis focusing on the age of the top 15% largest trees within each
 plot. The varying stand ages could be attributed to different intervals
 since the last deforestation that occurred prior to initiation of the
 Natural Forest Conservation Program. * Two bioclimatic variables -
 temperature seasonality (TS) and precipitation seasonality (PS) were
 extracted from the World Climate Dataset with a 1 km2 spatial resolution.
 ## Description of the local communities * The study region covers a large,
 natural forest area in northeastern China (39°N‒54°N latitude, 119°E‒134°E
 longitude) where coniferous and broadleaved mixed forests occur. The total
 study area covered approximately 700,000 km2, where the 379 circular field
 plots with relatively even cover, each measuring 0.1 ha, were used in this
 study. Each plot was equally divided into ten subplots (local communities)
 of 0.01 ha.