David P. Waetjen

Compounded effects of climate change and habitat alteration shift patterns of butterfly diversity.

Climate change and habitat destruction have been linked to global declines in vertebrate biodiversity, including mammals, amphibians, birds, and fishes. However, invertebrates make up the vast majority of global species richness, and the combined effects of climate change and land use on invertebrates remain poorly understood. Here we present 35 years of data on 159 species of butterflies from 10 sites along an elevational gradient spanning 0–2,775 m in a biodiversity hotspot, the Sierra Nevada Mountains of Northern California. Species richness has declined at half of the sites, with the most severe reductions at the lowest elevations, where habitat destruction is greatest. At higher elevations, we observed clear upward shifts in the elevational ranges of species, consistent with the influence of global warming. Taken together, these long-term data reveal the interacting negative effects of human-induced changes on both the climate and habitat available to butterfly species in California. Furthermore, the decline of ruderal, disturbance-associated species indicates that the traditional focus of conservation efforts on more specialized and less dispersive species should be broadened to include entire faunas when estimating and predicting the effects of pervasive stressors.

Contribution of Urban Expansion and a Changing Climate to Decline of a Butterfly Fauna

Butterfly populations are naturally patchy and undergo extinctions and recolonizations. Analyses based on more than 2 decades of data on Californias Central Valley butterfly fauna show a net loss in species richness through time. We analyzed 22 years of phenological and faunistic data for butterflies to investigate patterns of species richness over time. We then used 18-22 years of data on changes in regional land use and 37 years of seasonal climate data to develop an explanatory model. The model related the effects of changes in land-use patterns, from working landscapes (farm and ranchland) to urban and suburban landscapes, and of a changing climate on butterfly species richness. Additionally, we investigated local trends in land use and climate. A decline in the area of farmland and ranchland, an increase in minimum temperatures during the summer and maximum temperatures in the fall negatively affected net species richness, whereas increased minimum temperatures in the spring and greater precipitation in the previous summer positively affected species richness. According to the model, there was a threshold between 30% and 40% working-landscape area below which further loss of working-landscape area had a proportionally greater effect on butterfly richness. Some of the isolated effects of a warming climate acted in opposition to affect butterfly richness. Three of the 4 climate variables that most affected richness showed systematic trends (spring and summer mean minimum and fall mean maximum temperatures). Higher spring minimum temperatures were associated with greater species richness, whereas higher summer temperatures in the previous year and lower rainfall were linked to lower richness. Patterns of land use contributed to declines in species richness (although the pattern was not linear), but the net effect of a changing climate on butterfly richness was more difficult to discern.

Large Extent Volunteer Roadkill and Wildlife Observation Systems as Sources of Reliable Data

Large-extent wildlife-reporting systems have sets of goals and methods to facilitate standardized data collection, statistical analysis, informative visualizations, and use in decision-making within the system area. Many systems employ “crowds” of volunteers to collect these data at large spatial extents (e.g., US state or small country scale), especially along roadways. This raises the important question of how these systems could be standardized and the data made broadly useful in ecological and transportation studies, i.e. beyond the system area or goals. We describe two of the first and longest-running systems for volunteer observation of road-associated wildlife (live and dead) at the US state scale. The California Roadkill Observation System (CROS, http://wildlifecrossing.net/california) uses a form-based data entry system to report carcasses resulting from wildlife-vehicle collisions (WVC). Operating since 2009, it currently (June, 2017) contains 1,338 users and >54,000 observations of 424 species of ground-dwelling vertebrates and birds, making it one of the most successful examples of crowd-sourced, roadkill and wildlife reporting. Its sister system, the Maine Audubon Wildlife Road Watch (http://wildlifecrossing.net/maine) has a similar structure, and can accept data from transect surveys, animal tracks and scat observations, and reports of “no animal observed”. Both systems can operate as web-applications on a smart-phone (using a web browser), providing the ability to enter observations in the field. Locational accuracy for California observations was estimated to be +/-14 m (n=552 records). Species identification accuracy rate for observations with photographs was 97% (n=3,700 records). We propose that large extent, volunteer systems can be used to monitor wildlife occurrences along or away from roads and that these observations can be used to inform ecological studies and transportation mitigation planning.

Impacts of a millennium drought on butterfly faunal dynamics

BackgroundClimate change is challenging plants and animals not only with increasing temperatures, but also with shortened intervals between extreme weather events. Relatively little is known about diverse assemblages of organisms responding to extreme weather, and even less is known about landscape and life history properties that might mitigate effects of extreme weather. Our aim was to address this knowledge gap using a multi-decadal dataset of 163 butterfly species that recently experienced a millennium-scale drought. To understand faunal dynamics in the context of the millennium drought, we investigated the behavior of phenology (including date of first flight), species richness and diversity indices through time at 10 study sites spanning an elevational gradient. Linear models were developed to understand the differential sensitivity of butterflies to climate at low and high elevations.ResultsDates of first flight advanced across the elevational gradient during the drought, leading to an overall expansion of the flight window at low elevations and a compression of the flight window in the mountains. The number of species observed per year increased at lower elevations but decreased at higher elevations, apparently as a consequence of extreme sensitivity to hot and dry conditions.ConclusionMontane populations may be more sensitive to climatic extremes than expected based on availability of microclimates and spatial heterogeneity, while low-elevation populations (despite existing in degraded habitats) are buffered by life history plasticity.

Mapping Roadkill to Improve Driver and Wildlife Safety on Highways

POLICY BRIEF INSTITUTE OF TRANSPORTATION STUDIES TOOL PROFILE: Mapping Roadkill to Improve Driver and Wildlife Safety on Highways Fraser Shilling and David Waetjen Road Ecology Center, UC Davis For more information contact Fraser Shilling at: fmshilling@ucdavis.edu KEY TAKEAWAYS Issue Wildlife-vehicle collisions (WVC) pose a risk to drivers and cost U.S. society billions of dollars annually in property damage, emergency response, maintenance and mitigation, and lost economic activity. Reducing WVC requires identifying where these collisions are most common and what activities improve safety and protect wildlife. Collecting data on the extent and nature of WVC incidents is a challenge, however. Currently, Caltrans maintenance staff record their activities on paper in the field and then transcribe that information to a digital system when they return to the maintenance stations and regional offices. This system not only makes it challenging for individual staff to keep track of activities, it also reduces the chance that valuable information (like WVC location and wildlife species) will be retained and transcribed correctly. To improve data collection, the Road Ecology Center at UC Davis is developing tools such as a “one click” mobile app which will help Caltrans workers and others to collect WVC data in the field, with greater locational accuracy. The app will also enable Caltrains maintenance staff, who are often first responders to non-emergency roadside incidents, to track illegal dumping and as well as record roadside vegetation issues (e.g., areas that need mowing, weed-control, planting) and note fire hazards. Solution The Road Ecology Center has developed a smartphone application as a first step to putting a set of critical and contemporary reporting tools in the hands of the approximately 5,000 Caltrans Maintenance Division staff who clean up trash, collect wildlife carcasses, and manage the roadside along more than 12,000 miles of state highways. Eventually, the app and the system behind it will help both with finding hotspots of wildlife carcasses resulting from collisions and with carrying out other cleanup and maintenance activities (e.g., weed-management, trash cleanup) critical to improving state highway rights of way. • • Wildlife-vehicle collisions (WVC) pose a risk to drivers and annually costs billions of dollars annually. • • One of the greatest hurdles in reducing wildlife-vechile collisions is collecting data on the extend and nature of the incidents. • • The Road Ecology Center developed an easy-to-use smartphone application that streamlines wildlife- vehicle collision reporting for Caltrans Maintenance Division staff who maintain 12,000 miles of state highways. Figure 1. User-submitted photo from the California Roadkill Observation System.

The Butterfly Effect: An Approach to Web-Based Scientific Data Distribution and Management with Linkages to Climate Data and the Semantic Web

Environmental scientists generating longitudinal data that reliably track changes in biodiversity face additional challenges of data management and dissemination. An open source web framework can be used effectively to manage datasets while making research available at different levels of expertise, including for public environmental education. This chapter discusses the development of a web framework which links long-term butterfly presence/absence data with regional weather data, allowing researchers to investigate the relationship between butterfly populations and climate change, over time. The chapter concludes with a discussion of the semantic web, and how observational and monitoring data can become part of the growing Linked Data project.