DOI: 10.5061/dryad.8ns60
title: Data from: Effects of roads and land use on frog distributions across spatial scales and regions in the eastern and central United States

description: Aim: Understanding the scales over which land use affects animal
 populations is critical for conservation planning, and it can provide
 information about the mechanisms that underlie correlations between
 species distributions and land use. We used a citizen-science database of
 anuran surveys to examine the relationship between road density, land use,
 and the distribution of frogs and toads across spatial scales and regions
 of the United States. Location: Eastern and Central United States Methods:
 We compiled data on anuran occupancy collected from 1999-2013 across 13
 states in the North American Amphibian Monitoring Program, a citizen
 science survey of calling frogs. These data were indexed to measures of
 land use within buffers ranging from 300 m to 10 km. Results: The negative
 effects of road density and development on anuran richness were strongest
 at the smallest scales (300 – 1000 m), and this pattern was consistent
 across regions. In contrast, the relationships of anuran richness to
 agriculture and forest cover were similar across local scales but varied
 among regions. Richness had a negative relationship with agriculture/
 forest loss in the Midwest but a positive relationship with agriculture in
 the Northeast. Anuran richness was more closely related to
 primary/secondary road density than to rural road density, and the
 negative effects of larger roads increased at smaller scales. Individual
 species differed in the scales over which roads and development affected
 their distributions, but these differences were not closely related to
 either body size or movement ability. Main conclusions: This study further
 refines our understanding of the relationship between roads and amphibian
 populations and highlights the need for research into the specific
 mechanisms by which roads affect amphibians. Additionally, we find that
 relationships between land use and species richness can differ
 substantially across regions, demonstrating that one should use caution in
 generalizing from one region to another, even when species composition is
 similar.
description: Land use data and anuran
 species richness for North American Amphibian Monitoring Program survey
 sitesData from 587 NAAMP
 survey sites. NAAMP survey locations are organized as "stops"
 within "routes," each of which has a unique SiteID. Land use
 variables were measured within buffers of 300m, 600m, 1000m, 5km, and
 10km. Variables include "wet_prop" (proportion of area covered
 by wetland), "imperv" (proportion of area covered by impervious
 surface), "PROP_FOR" (proportion of area covered by forest),
 "PROP_DEV" (proportion of area covered by developed land uses,
 and "PROP_AGR" (proportion of area covered by row crop
 agriculture. Road-related variables are given as linear lengths (meters)
 within each buffer. Variables are T_ROAD_LEN (total road length),
 P_ROAD_LEN (primary (divided) roads), S_ROAD_LEN (secondary roads),
 O_ROAD_LEN (other roads, i.e. not P or S), and PS_ROAD_LEN (the sum of
 primary and secondary road lengths). Data also show the number of NAAMP
 surveys of each stop (Num.Surv), the number of years covered (Num.Years),
 mean car count during surveys (Car.Count), number of surveys with ambient
 noise (Noise.Num), and proportion of surveys that noted noise (NOISE_LEV =
 Noise.Num/Num.Surv). Amphibian presence/absence over all surveys are given
 for the species ANFO, HYCI, HYSQ, LICA, LICL, LIPA, LIPI, LISP, LISY,
 HYCV, PSTR (full scientific names are provided in the associated paper).
 NAs indicate sites outside the known range of each species. Richness is
 shown as the sum of all species detected at each stop, and NPP represents
 estimated Net Primary Productivity at that set (which provided a
 geographic expectation of anuran species richness).DDI_Marshetal.csv