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Wildlife species have defined activity patterns that are important for conserving biological rhythms and altering these rhythms can cause physiological stress. Species often shift activity patterns to minimize predation risks or to temporally partition competition. Thus, when a new predator or competitor is introduced into a community, the activity patterns of the whole community could be affected, and this effect may increase the stress wild pigs cause to native wildlife. To test the hypothesis that wild pig activity patterns affect those of native wildlife, we monitored activity patterns of native wildlife and wild pigs before and after aerial gunning events that manipulated pig activity patterns. Using the Statistical R-package – Overlap option, we generated species activity curves which showed aerial gunning caused a substantial shift in wild pig activity patterns from peaking near sunrise to peaking near sunset. Native species not directly at risk from aerial gunning, such as raccoon, armadillo, rabbits, squirrels, and opossum, shifted their activity patterns to a lesser degree than that of pigs, but most species adjusted activity peaks to favor lulls in pig activity. Thus, by manipulating swine activity patterns we provide evidence that wild pigs affect the activity patterns of many native wildlife species. Not only does our data demonstrate the flexibility of pigs to alter activity patterns to avoid removal, it also indicates that these animals cause an additional unappreciated stress on native wildlife by altering their biological rhythm.

Biological invasions often have negative effects on native wildlife and in the case of feral swine, also can cause extensive agricultural damage. As a result, the rapidly increasing swine populations and associated damages have led to wide-spread control efforts focused in agricultural areas. In a previous study, via camera trapping, we determined feral swine reduced observed vertebrate species richness by 26% when they invaded remnant forest patches in the Mississippi Alluvial Valley. To determine the effectiveness of removal efforts in recovering the lost vertebrate richness, in January 2018, we initiated a before-after control-impact designed experiment in 5 forest patches to monitor species richness before and after swine removals with camera traps. Also, we calculated swine activity patterns before and after aerial gunning to determine the degree to which feral swine alter behavior to avoid detection in future efforts. Preliminary data suggests a minimal species recovery following swine removal which may result from a lag in response to decreasing swine abundance or continued suppression from remaining swine populations. Preliminary data also indicate that swine immediately shifted their activity to avoid times of day when aerial gunning occurred. Thus, shifting swine behavior is likely to exacerbate the diminishing returns in removal effectiveness in a patch over a short time period. However, swine activity returned to normal within a year. These results are preliminary to a long-term experiment where we intend to increase patch sample size and continue to monitor species richness recovery as removals decrease swine populations.

Double-crested Cormorants (Phalacrocorax auritus) are the main source of depredation at catfish aquaculture facilities in Northwest Mississippi, resulting in significant economic loss. Understanding factors related to pond selection by cormorants could aid in mitigation practices to minimize further loss. We constructed occupancy models to estimate the probability of cormorant presence on catfish ponds against multiple variables associated with each ponds physical surroundings and internal conditions. We also explored cormorant use of aquaculture and natural habitat by using logistic regression to model the proportion of cormorants on aquaculture compared to natural habitat and influences of seasonal variation. Cormorant presence data was collected by aerial survey (n=35) from October to April, of 2015-2017, accounting for an average of 973 catfish ponds and 26 natural water bodies each year. Our results indicate ponds located farther away from trees and activity centers, such as farm workshops, have a higher probability of cormorant use. Larger ponds, and ponds nearer the edge of pond clusters also have an increased probability of use. Specific pond contents influenced cormorant use, including fish species cultured, pond systems, and fish types. From October through January cormorants were distributed more on natural habitat. However, cormorants’ proportional use of aquaculture steadily increased beginning in February. This temporal shift from natural habitat toward aquaculture coincides with cormorant spring migration, indicating an increase in foraging of catfish in preparation for the migration north.

Population-level demographic characteristics as estimated by standard logistic growth models (i.e., carrying capacity and intrinsic growth rate) should vary with changes in habitat quality and availability of resources. However, few published studies have tested this hypothesis by comparing population growth rates across broad bioclimatic gradients, and fewer still the carrying capacities of those populations. We used time series data on moose (Alces alces) population densities based on aerial census and hunter harvest data for 34 management units across Ontario to estimate local carrying capacities and intrinsic growth rates. These population parameters were then regressed against associated habitat covariates for each management unit to assess how moose demography changes across a broad gradient of productivity, habitat abundance, and timber harvest. Moose carrying capacity was found to increase with increasing forest productivity as measured by DNDVI and the proportion of mixedwood stands in the forest. Both variables are plausibly indicative of high quality forage abundance for moose. Moose carrying capacity decreased with the proportion of forest stands harvested for timber annually, suggesting that immediate removal of forest stands and increased access by hunters temper maximum population size. Maximum rates of population growth by Ontario moose did not vary predictably with any of the landscape covariates tested. These findings contribute to our understanding of changes in demography across broad geographic and bioclimatic gradients and suggest that crude population estimators may be derived based on known habitat preferences and resource availability without a priori knowledge of animal abundance. (PDF) Characterizing demographic parameters across environmental gradients: A case study with Ontario moose (Alces alces). Available from: https://www.researchgate.net/publication/280936410_Characterizing_demographic_parameters_across_environmental_gradients_A_case_study_with_Ontario_moose_Alces_alces [accessed Oct 29 2018].