A Highly Aggregated Geographical Distribution of Forest Pest Invasions in the USA

Diversity and DistributionsDiversity and Distributions, 2013

Liebhold, Andrew M.; McCullough, Deborah G.; Blackburn, Laura M.; Frankel, Susan J.; Von Holle, Betsy; Aukema, Juliann E.

Aim:  Geographical variation in numbers of established non-native species provides clues to the underlying processes driving biological invasions. Specifically, this variation reflects landscape characteristics that drive non-native species arrival, establishment and spread. Here, we investigate spatial variation in damaging non-native forest insect and pathogen species to draw inferences about the dominant processes influencing their arrival, establishment and spread.
Location:  The continental USA, including Alaska (Hawaii not included).
Methods: We assembled the current geographical ranges (county-level) of 79 species of damaging non-indigenous forest insect and pathogen species currently established in the continental USA. We explored statistical associations of numbers of species per county with habitat characteristics associated with propagule pressure and with variables reflecting habitat invasibility. We also analysed relationships between the geographical area occupied by each pest species and the time since introduction and habitat characteristics.

Variables associated with habitat invasibility measured at the county-level: (a) forested land area; (b) numbers of tree species detected in FIA surveys; (c) numbers of tree families detected in FIA surveys; (d) numbers of tree genera detected in FIA surveys.

Variables associated with habitat invasibility measured at the county-level: (a) forested land area; (b) numbers of tree species detected in FIA surveys; (c) numbers of tree families detected in FIA surveys; (d) numbers of tree genera detected in FIA surveys.

Results:  The geographical pattern of non-native forest pest species richness is highly focused, with vastly more species in the north-eastern USA. Geographical variation in species richness is associated with habitat factors related to both propagule pressure and invasibility. Ranges of the non-native species are related to historical spread; range areas are strongly correlated with time since establishment. The average (all species) radial rate of range expansion is 5.2 km yr-1, and surprisingly, this rate did not differ among foliage feeders, sap-feeders, wood borers and plant pathogens.
Main conclusions:  Forest pest species are much more concentrated in the north-eastern region of the USA compared with other parts of the country. This pattern most likely reflects the combined effects of propagule pressure (pest arrival), habitat invasibility (pest establishment) and invasion spread. The similarity in historical spread among different types of organisms indicates the importance of anthropogenic movement in spread.”

Spatial Assessment of Attitudes Toward Tigers in Nepal

AMBIOAMBIO: A Journal of the Human Environment, Published Online 09 July 2013

Neil H. Carter, Shawn J. Riley, Ashton Shortridge, Binoj K. Shrestha, and Jianguo Liu

“In many regions around the world, wildlife impacts on people (e.g., crop raiding, attacks on people) engender negative attitudes toward wildlife. Negative attitudes predict behaviors that undermine wildlife management and conservation efforts (e.g., by exacerbating retaliatory killing of wildlife). Our study (1) evaluated attitudes of local people toward the globally endangered tiger (Panthera tigris) in Nepal’s Chitwan National Park; and (2) modeled and mapped spatial clusters of attitudes toward tigers. Factors characterizing a person’s position in society (i.e., socioeconomic and cultural factors) influenced attitudes toward tigers more than past experiences with tigers (e.g., livestock attacks).

Maps showing percentage of respondents per ward that (a) had <8 years of education, (b) were from lower caste Hindu and Terai Tibeto-Burmese ethnic groups, (c) were female, and (d) reported that a tiger had threatened/attacked a family member in the past. Percentage categories were defined by equal intervals.

Maps showing percentage of respondents per ward that (a) had

“A spatial cluster of negative attitudes toward tigers was associated with concentrations of people with less formal education, people from marginalized ethnic groups, and tiger attacks on people. Our study provides insights and descriptions of techniques to improve attitudes toward wildlife in Chitwan and many regions around the world with similar conservation challenges.”