Many nonexperimental studies have shown positive correlations between resource abundance and vertebrate abundance. These relationships, however, are difficult to interpret because of confounding factors that may independently determine the abundance of vertebrates and their resources. Moreover, verifying links between vertebrate and resource abundance is complex because human perception of resource abundance may differ from that of nonhuman vertebrates and because manipulating resource abundance on an ecologically meaningful scale is difficult.We studied the dependency of frugivores on fruit abundance in eastern Amazonian floodplain forests dominated by one species of palm tree (Euterpe oleracea) from which people harvest fruit. We first compared spatial and temporal use by frugivorous parrots of four sites dominated by E. oleracea and four sites with no E. oleracea. Parrots spent 48-92% more time in the former, where their activity over the fruiting season mirrored the abundance of fruits. To test whether fruit abundance was the mechanism underlying these patterns, we removed fruit at two intensities in replicated 1.8-ha plots, and then monitored responses of frugivorous birds and mammals. High-intensity removal (75% of ripe fruit harvested) significantly reduced the number of frugivorous bird individuals by 29% and the length of frugivorous bird visits by 68%, relative to controls. In contrast, low-intensity removal (41% of ripe fruit removed) had no impact on these metrics. Frugivore species richness did not differ among treatments and controls, but the composition of the frugivore community was altered by harvest, with the presence of 11 species being linked to fruit abundance. Nonfrugivorous birds did not respond to either intensity of fruit harvest. The number of fruit-eating mammal species was 58% lower in both the low-and high-removal treatments, relative to control plots.These results verify that fruit abundance influences the species composition of frugivore communities and the abundance and foraging behavior of individual species. They also document short-term dependency of fruit-eating mammals on fruit abundance. Harvest of fruit from forest systems, a common practice in tropical forests, therefore can affect populations of fruit-eating animals.

High variation in seed size, as is common among angiosperms, may be maintained in a plant species when several factors select for seed size. Variation may also result from differences among adult plants, such as nutrient and water availability or the amount of photosynthetic tissue. In a study of Sabal palmetto seed ecology I found high seed size variation both within- and among-palms, and investigated possible factors maintaining this variation. Seed size was positively correlated with the number of leaves on parent palms. Larger seeds produced more vigorous seedlings that had greater leaf length, area, and mass, and greater root mass. Caryobruchus gleditsiae (Bruchidae: Coleoptera), whose larvae develop within palm seeds, preferentially oviposited on larger seeds, which in turn produced larger beetle offspring. By choosing the largest seeds available, ovipositing beetles thus affect both the quantity and the quality of seeds available for recruitment. I conclude that because beetle predation selects against large seeds, while larger seeds promote seedling vigor, the maintenance of seed size variation may be an adaptation of S. palmetto promoting both seed escape from predators and seedling vigor.

Livestock industries are vulnerable to disease threats, which can cost billions of dollars and have substantial negative social ramifications. Losses are mitigated through increased use of disease-related biosecurity practices, making increased biosecurity an industry goal. Currently, there is no industry-wide standard for sharing information about disease incidence or on-site biosecurity strategies, resulting in uncertainty regarding disease prevalence and biosecurity strategies employed by industry stakeholders. Using an experimental simulation game, with primarily student participants, we examined willingness to invest in biosecurity when confronted with disease outbreak scenarios. We varied the scenarios by changing the information provided about 1) disease incidence and 2) biosecurity strategy or response by production facilities to the threat of disease. Here we show that willingness to invest in biosecurity increases with increased information about disease incidence, but decreases with increased information about biosecurity practices used by nearby facilities. Thus, the type or context of the uncertainty confronting the decision maker may be a major factor influencing behavior. Our findings suggest that policies and practices that encourage greater sharing of disease incidence information should have the greatest benefit for protecting herd health.

Non-timber forest product (NTFP) extraction is a popular alternative to timber extraction that figures prominently in efforts to utilize tropical forests sustainably. But the ability to conserve biodiversity through NTFP management, particularly in extractive reserves in Amazonia, has remained untested. We found that intensive management of Euterpe oleracea (Palmae) fruit, one of the most important extractive products in the Amazon, has substantial impacts on biodiversity, whereas moderate management does not. We mimicked traditional levels of fruit harvest in a replicated experiment over one fruiting season. High-intensity harvest (75% of fruits removed) reduced avian frugivore species diversity by 22%. Low-intensity harvest (40% of fruits removed), however, had no effect on diversity. On a larger scale, we found that forests with enriched densities of E. oleracea supported more fruit-eating birds but fewer non fruit-eating birds than nonenriched forests. Taken together, these results suggest that intensive NTFP management to meet market demands may trigger substantial ecological impacts, at least at the level of our study. E. oleracea harvest should be limited where conservation of biodiversity is a goal.

Hog producers' operational decisions can be informed by an awareness of risks associated with emergent and endemic diseases. Outbreaks of porcine epidemic diarrhea virus (PEDv) have been re-occurring every year since the first onset in 2013 with substantial losses across the hog production supply chain. Interestingly, a decreasing trend in PEDv incidence is visible. We assert that changes in human behaviors may underlie this trend. Disease prevention using biosecurity practices is used to minimize risk of infection but its efficacy is conditional on human behavior and risk attitude. Standard epidemiological models bring important insights into disease dynamics but have limited predictive ability. Since research shows that human behavior plays a driving role in the disease spread process, the explicit inclusion of human behavior into models adds an important dimension to understanding disease spread. Here we analyze PEDv incidence emerging from an agent-based model (ABM) that uses both epidemiological dynamics and algorithms that incorporate heterogeneous human decisions. We investigate the effects of shifting fractions of hog producers between risk tolerant and risk averse positions. These shifts affect the dynamics describing willingness to increase biosecurity as a response to disease threats and, indirectly, change infection probabilities and the resultant intensity and impact of the disease outbreak. Our ABM generates empirically verifiable patterns of PEDv transmission. Scenario results show that relatively small shifts (10% of the producer agents) toward a risk averse position can lead to a significant decrease in total incidence. For significantly steeper decreases in disease incidence, the model's hog producer population needed at least 37.5% of risk averse. Our study provides insight into the link between risk attitude, decisions related to biosecurity, and consequent spread of disease within a livestock production system. We suggest that it is possible to create positive, lasting changes in animal health by nudging the population of livestock producers toward more risk averse behaviors. We make a case for integrating social and epidemiological aspects in disease spread models to test intervention strategies intended to improve biosecurity and animal health at the system scale.