Temporal and spatial harvest patterns of river otter in Louisiana and its potential use as a bioindicator species of water quality

Louisiana is the leading state in number of river otters used in reintroduction programs in other states and in the production of pelts. However, habitat loss and degradation have prompted concern about the status of otter populations. This dissertation undertakes a spatial and temporal analysis of river otter harvest activity and examines environmental factors related to monitoring mercury levels in streams in Louisiana. Harvest data for 1957-2004 were analyzed to identify spatial and temporal trends in otter harvest activity. Changes have occurred in the last 20 years in the spatial dynamics of otter harvest in Louisiana, these include an increasing proportion of harvested otters coming from upland parishes in more recent years, and an increase in the proportion of trappers catching otters in that region. Spatial analysis indicated that this shift in harvesting activity has been gradual rather than abrupt. An explanation for this shift could be a greater interest of upland trappers in catching otters because of increasing otter pelt price and a decline in pelt price for other furbearer species. Analyses indicated that a management plan based on spatial control of harvest could be an option in Louisiana, with rice fields and protected areas playing an important role in the management/conservation plan. Temporal analysis suggested that the number of otters harvested 1 and 5 years ago has an impact on number of otters harvested at present time. An autoregressive model was developed to describe this association and to forecast number of otter pelts to be harvested 1 year in the future. The structure identified in the harvest data was used to develop a model to describe the dynamics of the otter populations. The simulation using 4-year and 8-year periods offered a reasonable approximation to the estimated cyclic dynamics of otter population in Louisiana. Mercury levels in otters were compared to levels in fish collected in different streams in Louisiana. Mercury levels in otters were higher than in fish. Otter samples also identified streams where mercury level in water may require further analysis. These results suggested that a mercury monitoring program based on river otters could be feasible in Louisiana

SPATIALLY EXPLICIT MODEL OF AREAS BETWEEN SUITABLE BLACK BEAR HABITAT IN EAST TEXAS AND BLACK BEAR POPULATIONS IN LOUISIANA, ARKANSAS, AND OKLAHOMA

Although black bears (Ursus americanus, Ursus americanus luteolus) were once found throughout the south-central United States, unregulated harvest and habitat loss resulted in severe range retractions and by the beginning of the twentieth century populations in Oklahoma, Louisiana, Texas and Arkansas were nearing extirpation. In response to these losses, translocation programs were initiated in Arkansas (1958-1968 & 2000-2006) and Louisiana (1964-1967 & 2001-2009). These programs successfully restored bears to portions of Louisiana and Arkansas, and, as populations in Arkansas began dispersing, to Oklahoma. In contrast, east Texas remains unoccupied despite the existence of suitable habitat in the region. To facilitate the establishment of a breeding population in east Texas, I sought to identify suitable habitat which bears could use for dispersal between known bear locations in Louisiana, Arkansas and Oklahoma and the east Texas recovery units. I utilized Maxent, a machine learning software, to model habitat suitability in this region. I collected known black bear presence locations (n=18,241) from state agencies in Louisiana, Oklahoma, Arkansas and east Texas and filtered them to reduce spatial autocorrelation (n=664). I also collected spatial data sets based on known black bear ecology to serve as environmental predictor variables. The model was developed at 30-m resolution and encompassed 417,076 km 2. The final model was selected to minimize model over-fitting while maintaining a high test Area Under the Receiver Operating Curve (AUC TEST)score. For final model interpretation and analysis, I used the 10th percentile training threshold available in Maxent which excludes the lowest 10% of predicted presence suitability scores from the binary predictive map, thus resulting in a more conservative predictive map. The final 10th percentile model predicted 43.7% of the pixels in the study area as suitable and 53.7 % percent of the pixels identified as potential recovery units by Kaminski et al. (2013, 2014) as suitable. To focus management efforts, I identified three movement zones with a high proportion of suitable habitat within which connectivity analyses were performed. Suitable patches greater than or equal to 12 km2 were classified within ArcGIS as stepping stone patches. Buffers of 3,500 m were generated around these patches to determine the level of functional connectivity in each zone. The final Maxent model confirmed that suitable bear habitat exists between source populations and the east Texas recovery units. The importance of percent of mast producing forest, percentage of cultivated crops and percentage of protected lands reflect what is known about basic bear biology and ecology. Furthermore, 153 stepping stone patches were identified within the movement zones, demonstrating that there is a reasonable chance of bears naturally dispersing to east Texas using the habitat identified in this study. Thus, protection of existing bear habitat and the stepping stone patches identified in this study should be a priority for managers seeking to facilitate natural bear recolonization of east Texas

Broad-Scale Relations between Conservation Reserve Program and Grassland Birds: Do Cover Type, Configuration and Contract Age Matter?

The Conservation Reserve Program (CRP) is a voluntary cropland set-aside program where environmentally-sensitive cropland is retired to a conservation practice. Grassland birds should benefit because most CRP is grass habitat and because amount of land in CRP is highest in agriculture-dominated areas of the United States where grassland habitat has been most impacted. We used the Breeding Bird Survey and Common Land Unit (CLU) data (spatially-explicit data of farm field boundaries and land cover) to identify relations between types and configurations of CRP and grassland bird abundance in 3 Midwestern states. All 13 species we studied were related to at least one aspect of CRP habitat - specific conservation practices (e.g., native vs. exotic grass), CRP habitat configuration, or habitat age. Treating all types of CRP as a single habitat type would have obscured bird-CRP relations. Based on our results, creating a mosaic of large and small set-aside patches could benefit both area-sensitive and edge-associated grassland birds. Additionally, northern bobwhite and other birds that use early successional grasslands would benefit from periodic disturbances. CRP, agrienvironment schemes, and other government-sponsored set-aside programs may be most successful when administered as part of a targeted, regional conservation plan

Spatial Autocorrelation and Pseudoreplication in Fire Ecology

Fire ecologists face many challenges regarding the statistical analyses of their studies. Hurlbert (1984) brought the problem of pseudoreplication to the scientific community’s attention in the mid 1980’s. Now, there is a new issue in the form of spatial autocorrelation. Spatial autocorrelation, if present, violates the traditional statistical assumption of observational independence. What, if anything, can the fire ecology community do about this new problem? An understanding of spatial autocorrelation, and knowledge of available methods used to reduce the effect of spatial autocorrelation and pseudoreplication will greatly assist fire ecology researchers

SNAPSHOT USA 2019 : a coordinated national camera trap survey of the United States

This article is protected by copyright. All rights reserved.With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August - 24 November of 2019). We sampled wildlife at 1509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the USA. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as well as future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.Publisher PDFPeer reviewe

Effects of the Conservation Reserve Program on Northern Bobwhite and Grassland Birds

The Conservation Reserve Program (CRP) has converted just over 36 million acres of cropland into potential wildlife habitat, primarily grassland. Thus, the CRP should benefit grassland songbirds, a group of species that is declining across the United States and is of conservation concern. Additionally, the CRP is an important part of multi-agency, regional efforts to restore northern bobwhite populations. However, comprehensive assessments of the wildlife benefits of CRP at regional scales are lacking. We used Breeding Bird Survey and National Resources Inventory data to assess the potential for the CRP to benefit northern bobwhite and other grassland birds with overlapping ranges and similar habitat associations. We built regression models for 15 species in seven different ecological regions. Forty-nine of 108 total models contained significant CRP effects (P \u3c 0.05), and 48 of the 49 contained positive effects. Responses to CRP varied across ecological regions. Only eastern meadowlark was positively-related to CRP in all the ecological regions, and western meadowlark was the only species never related to CRP. CRP was a strong predictor of bird abundance compared to other land cover types. The potential for CRP habitat as a regional conservation tool to benefit declining grassland bird populations should continue to be assessed at a variety of spatial scales. We caution that bird-CRP relations varied from region to region and among species. Because the NRI provides relatively coarse resolution information on CRP, more detailed information about CRP habitats (spatial arrangement, age of the habitat (time since planting), specific conservation practices used) should be included in future assessments to fully understand where and to what extent CRP can benefit grassland birds

Patterns of Vertebrate Abundance in a Tropical Mosaic Landscape

Multi‐faceted field sampling in a mosaic landscape in Venezuela generated insights on how topographical characteristics, forest composition, degree of habitat interspersion, and paleoecology influenced the abundance and distribution of vertebrates. Physical heterogeneity resulted in distinct vegetation types and a very uneven distribution of medium to large‐sized vertebrates. Variations in forest composition resulted in dramatic contrasts in primate densities. White‐tailed deer densities varied an order of magnitude between vegetation types. Yellow‐knobbed curassow densities peaked in moist forest. Similar chachalaca densities were encountered in dry forest. Although there was spatial overlap between jaguars and pumas, from a large‐scale perspective pumas made more use of drier habitats. In select habitats the abundance and biomass of red‐footed tortoises exceeded that of multiple species of large native mammals combined. This variation in animal abundance highlights the significance of scale in the interpretation of ecological data

Revealing Community Perceptions for Ecological Restoration Using a Soft System Methodology

Abstract Human perceptions under unstructured forms contain valuable information for ecological restoration (ER). To aid in ER, this paper introduces a working process to analyze the unstructured information for the case study of black bear restoration (BBR) in East Texas where understanding of the perceptions of stakeholders at a community level is needed. We identified the current situation, revealed stakeholders and their interactions, and developed actions for change for BBR. Our techniques included recording discussions in meetings, Soft Systems Methodology, and stakeholder analysis. Results indicated the current situation of BBR with human-bear and human-human conflicts. We figured out that information exchange was interrupted in the public, a potential cause for conflicts. Through a systemization, results showed various roles of key stakeholders and constraints for BBR. We found that local state agencies and local residents (particularly landowners) are the key decision-makers for BBR success. Their collaboration can result in a small portion of success (1/9) that can be increased by more cooperation. The SSM framework introduced in this study can be used for modeling community perceptions in ecological restoration.Keywords Softsystemsmethodology.Ecologicalrestoration.Communityperceptions.Black bearrestoration.Probabilitysucces

Deciphering Ecological Barriers to North American River Otter (Lontra canadensis) Gene Flow in the Louisiana Landscape

For North American river otters (Lontra canadensis) in Louisiana, statewide distribution, availability of aquatic habitats, and the absence of physical barriers to dispersal might suggest that they exist as a large, panmictic population. However, the wide variety of habitat types in this region, and the dynamic nature of these habitats over time, could potentially structure river otter populations in accordance with cryptic landscape features. Recently developed landscape genetic models offer a spatially explicit approach that could be useful in identifying potential barriers to the movement of river otters through the dynamic aquatic landscape of Louisiana. We used georeferenced multilocus microsatellite genotypes in spatially implicit (STRUCTURE) and spatially explicit (GENELAND) models to characterize patterns of landscape genetic structure. All models identified 3 subpopulations of river otters in Louisiana, corresponding to Inland, Atchafalaya River, and Mississippi River regions. Variation in breeding seasonality, brought about by variation in prey abundance between inland and coastal populations, may have contributed to genetic differentiation among populations. It is also possible that the genetic discontinuities we observed indicate a correlation between otter distribution and access to freshwater. Regardless of the mechanism, it is likely that any genetic differentiation among subpopulations is exacerbated by relatively poor dispersal