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BackgroundThe movement behavior of an animal is determined by extrinsic and intrinsic factors that operate at multiple spatio-temporal scales, yet much of our knowledge of animal movement comes from studies that examine only one or two scales concurrently. Understanding the drivers of animal movement across multiple scales is crucial for understanding the fundamentals of movement ecology, predicting changes in distribution, describing disease dynamics, and identifying efficient methods of wildlife conservation and management.MethodsWe obtained over 400,000 GPS locations of wild pigs from 13 different studies spanning six states in southern U.S.A., and quantified movement rates and home range size within a single analytical framework. We used a generalized additive mixed model framework to quantify the effects of five broad predictor categories on movement: individual-level attributes, geographic factors, landscape attributes, meteorological conditions, and temporal variables. We examined effects of predictors across three temporal scales: daily, monthly, and using all data during the study period. We considered both local environmental factors such as daily weather data and distance to various resources on the landscape, as well as factors acting at a broader spatial scale such as ecoregion and season.ResultsWe found meteorological variables (temperature and pressure), landscape features (distance to water sources), a broad-scale geographic factor (ecoregion), and individual-level characteristics (sex-age class), drove wild pig movement across all scales, but both the magnitude and shape of covariate relationships to movement differed across temporal scales.ConclusionsThe analytical framework we present can be used to assess movement patterns arising from multiple data sources for a range of species while accounting for spatio-temporal correlations. Our analyses show the magnitude by which reaction norms can change based on the temporal scale of response data, illustrating the importance of appropriately defining temporal scales of both the movement response and covariates depending on the intended implications of research (e.g., predicting effects of movement due to climate change versus planning local-scale management). We argue that consideration of multiple spatial scales within the same framework (rather than comparing across separate studies post-hoc) gives a more accurate quantification of cross-scale spatial effects by appropriately accounting for error correlation.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-017-0105-1) contains supplementary material, which is available to authorized users.

Coastal wetlands are among the most productive and carbon-rich ecosystems on Earth. Long-term carbon storage in coastal wetlands occurs primarily belowground as soil organic matter (SOM). In addition to serving as a carbon sink, SOM influences wetland ecosystem structure, function, and stability. To anticipate and mitigate the effects of climate change, there is a need to advance understanding of environmental controls on wetland SOM. Here, we investigated the influence of four soil formation factors: climate, biota, parent materials, and topography. Along the northern Gulf of Mexico, we collected wetland plant and soil data across elevation and zonation gradients within 10 estuaries that span broad temperature and precipitation gradients. Our results highlight the importance of climate-plant controls and indicate that the influence of elevation is scale and location dependent. Coastal wetland plants are sensitive to climate change; small changes in temperature or precipitation can transform coastal wetland plant communities. Across the region, SOM was greatest in mangrove forests and in salt marshes dominated by graminoid plants. SOM was lower in salt flats that lacked vascular plants and in salt marshes dominated by succulent plants. We quantified strong relationships between precipitation, salinity, plant productivity, and SOM. Low precipitation leads to high salinity, which limits plant productivity and appears to constrain SOM accumulation. Our analyses use data from the Gulf of Mexico, but our results can be related to coastal wetlands across the globe and provide a foundation for predicting the ecological effects of future reductions in precipitation and freshwater availability. Coastal wetlands provide many ecosystem services that are SOM dependent and highly vulnerable to climate change. Collectively, our results indicate that future changes in SOM and plant productivity, regulated by cascading effects of precipitation on freshwater availability and salinity, could impact wetland stability and affect the supply of some wetland ecosystem services.

The effects of a zinc supplement on maternal zinc status and milk zinc concentrations through > or = 7 mo of lactation were examined. Seventy-one lactating women received either a daily 15-mg zinc supplement (ZS, n = 40) or placebo (NZS, n = 31) started by 2 wk postpartum in a double-blind, randomized design. Overall mean zinc intakes were 13.0 +/- 3.4 mg/d for the NZS group and 25.7 +/- 3.9 mg/d (including supplement) for the ZS group. Plasma zinc concentrations of the ZS group were significantly higher than those of the NZS group (P = 0.05). Milk zinc concentrations declined significantly over the course of the study for all subjects but were not affected by zinc supplementation. The mean dietary zinc intake observed in the nonsupplemented group was adequate to maintain normal maternal zinc status and milk zinc concentrations through > or = 7 mo lactation. Similar controlled intervention trials in less well-nourished populations will be required to assess the impact of lower zinc intakes on milk zinc concentrations.

Contact rates vary widely among individuals in socially structured wildlife populations. Understanding the interplay of factors responsible for this variation is essential for planning effective disease management. Feral swine (Sus scrofa) are a socially structured species which pose an increasing threat to livestock and human health, and little is known about contact structure. We analyzed 11 GPS data sets from across the United States to understand the interplay of ecological and demographic factors on variation in co‐location rates, a proxy for contact rates. Between‐sounder contact rates strongly depended on the distance among home ranges (less contact among sounders separated by >2 km; negligible between sounders separated by >6 km), but other factors causing high clustering between groups of sounders also seemed apparent. Our results provide spatial parameters for targeted management actions, identify data gaps that could lead to improved management and provide insight on experimental design for quantitating contact rates and structure.

Intermediate marsh-Typical vegetation is frequently dominated by Leptochloa fusca, Panicum virgatum, Paspalum vaginatum, Phragmites australis, or Schoenoplectus americanus. Both intermediate and brackish marshes can be dominated by Spartina patens, but intermediate marshes dominated by Spartina patens have a higher species richness often including Sagittaria lancifolia, Schoenoplectus americanus, Eleocharis spp., and (or) Cyperus spp. Brackish marsh-Typical vegetation is often dominated by Spartina patens but is occasionally dominated by Spartina cynosuroides, Spartina spartinae, or Bolboschoenus robustus. Both intermediate and brackish marshes can be dominated by Spartina patens, but brackish marshes dominated by Spartina patens typically have a small number of other species such as Spartina alterniflora, Distichlis spicata, Juncus roemerianus, or Bolboschoenus robustus. Saline (saltwater) marsh-Typical vegetation is frequently dominated by Spartina alterniflora, Distichlis spicata, or Avicennia germinans.

northern extent of fresh marshes to the southern end of saline (saltwater) marshes on the beaches of the gulf or of coastal bays. Navigation along these transects and to each sampling site was accomplished by using Global Positioning System (GPS) technology and geographic information system (GIS) software operating on a ruggedized laptop, a procedure that was established during the 1997 vegetation survey by Chabreck and Linscombe. As the surveyors reached each sampling station, dominant plant species were listed and their abundance classified. Based on species composition and abundance each marsh sampling station was assigned a marsh type: fresh, intermediate, brackish, or saline (saltwater) marsh (Visser and others, 1998, 2000, 2002) The data generated from the survey were later delineated by using the same base map as that used to map the data collected during the 1997 (Chabreck and Linscombe) and 2001 (Linscombe and Chabreck, n.d.) surveys. Delineations of marsh boundaries usually followed natural levees, bayous, or other features that impede or restrict water flow.