David M. Marsh

Community science (CS) data can increasingly address a range of interesting questions in herpetology. However, data from unstructured CS projects like iNaturalist are collected in a very different manner than in traditional herpetological surveys, and this could lead to erroneous conclusions about herpetological communities. We compared inferences about species richness, diversity, and the representation of individual species from 71 sites in the United States that had both published herpetological surveys and adequate samples of iNaturalist observations. After adjusting for sample size, we found no significant differences in observed species richness between traditional survey data and iNaturalist data, and we found relatively high correlations between the two data sources in observed species richness across sites. However, the overlap between species lists derived from iNaturalist versus traditional surveys was only moderate, with reptile lists typically having 40–60% shared species and amphibian lists having 50–75% shared species. Furthermore, species diversity, and particularly evenness, differed consistently between the data sources, with observations more evenly spread among species in iNaturalist data as compared to traditional survey data. Likewise, correlations in species counts between the two data sets at individual sites were often low, and correlations in species diversity across sites were much lower than correlations in species richness. With respect to individual species, some species in each taxonomic group were consistently over- and under-represented in iNaturalist data compared to traditional survey data. Over-represented species included Red-backed Salamanders, Fowler's Toads, Eastern Fence Lizards, and Gopher Snakes, whereas under-represented species included White-spotted Slimy Salamanders, Gray Treefrogs, Six-lined Racerunners, Milk Snakes, and Musk Turtles. Overall, our results suggest that unstructured CS data could be useful for estimating species richness at individual sites or for comparing species richness across sites, particularly when sample sizes are high (e.g., hundreds to thousands of observations). However, these data sources should not be used to analyze community structure or diversity, at least without correcting for biases in CS data with respect to how likely different species are to be recorded.

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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 to 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.

Answering large-scale questions in ecology can involve time-consuming data compilation. We show how networks of undergraduate classes can make these projects more manageable and provide an authentic research experience for students. With this approach, we examined the factors associated with plant species richness in US national wildlife refuges. We found that the richness of harmful invasive plants and the richness of native plants were positively correlated in mainland refuges but negatively correlated in island refuges. Nonnative richness and invasive richness were also positively correlated with colonization pressure as indicated by nonnative richness around each refuge. Associations between refuge characteristics and invasive plants varied substantially among regions, with refuge area and habitat diversity important predictors of invasion in some regions but not in others. Our results serve to identify the refuges that are most susceptible to plant invasion and demonstrate the potential value of a new model for education and research integration.

Territoriality has been well-documented in terrestrial plethodontid salamanders. However, most studies of territoriality have focused either on defense of single cover objects or on defense of areas of forest floor. In nature, cover objects tend to occur in groups, and little is known about how cover-object distributions affect territory defense and salamander spatial associations. We manipulated cover-object spacing within a home range and used mark–recapture data to examine the effects of these manipulations on intra- and intersexual spatial associations in the red-backed salamander, Plethodon cinereus. Similar total numbers of salamanders were found in the different treatments, and salamanders moved between cover objects with similar frequency regardless of cover-object spacing. However, male spatial associations were affected by cover-object spacing, with males never found simultaneously under adjacent cover objects. Furthermore, the spatial associations of males and females differed among the cover-object spacing treatments. Males and females shared the same cover object 76% of the time when cover objects were adjacent, but only 37% of the time when cover objects were separated by 1 m. Our results suggest that P. cinereus often use multiple cover objects within a home range, and that males may defend these while they are using them. Additionally, males and females appear to adjust their use of cover objects with respect to the home ranges of opposite sex salamanders.

"Evaluating methods for sampling stream salamanders across multiple observers and habitat types" published on 01 Jan 2009 by Brill.

Abstract:  Animal and plant population monitoring programs are critical for identifying species at risk, evaluating the effects of management or harvest, and tracking invasive and pest species. Nevertheless, monitoring activities are highly decentralized, which makes it difficult for researchers or conservation planners to get a good general picture of what real‐world monitoring programs actually entail. We used a Web‐based survey to collect information on population monitoring programs. The survey focused on basic questions about each program, including motivations for monitoring, types of data being collected, spatiotemporal design of the program, and reasons for choosing that design. We received responses from 311 people involved in monitoring of various species and used these responses to summarize ongoing monitoring efforts. We also used responses to determine whether monitoring strategies have changed over time and whether they differed among monitoring agencies. Most commonly, monitoring entailed collection of count data at multiple sites with the primary goal of detecting trends. But we also found that goals and strategies for monitoring appeared to be diversifying, that area‐occupied and presence–absence approaches appeared to be gaining in popularity, and that several other promising approaches (monitoring to reduce parameter uncertainty, risk‐based monitoring, and directly linking monitoring data to management decisions) have yet to become widely established. We suggest that improved communication between researchers studying monitoring designs and those who are charged with putting these designs into practice could further improve monitoring programs and better match sampling designs to the objectives of monitoring programs.