Anthropogenic activity is driving population declines and extinctions of large-bodied, fruit-eating animals worldwide. Loss of these frugivores is expected to trigger negative cascading effects on plant populations if remnant species fail to replace the seed dispersal services provided by the extinct frugivores. A collapse of seed dispersal may not only affect plant demography (i.e., lack of recruitment), but should also supress gene flow via seed dispersal. Yet little empirical data still exist demonstrating the genetic consequences of defaunation for animal-dispersed plant species. Here, we first document a significant reduction of seed dispersal distances along a gradient of human-driven defaunation, with increasing loss of large- and medium-bodied frugivores. We then show that local plant neighbourhoods have higher genetic similarity, and smaller effective population sizes when large seed dispersers become extinct (i.e., only small frugivores remain) or are even partially downgraded (i.e., medium-sized frugivores providing less efficient seed dispersal). Our results demonstrate that preservation of large frugivores is crucial to maintain functional seed dispersal services and their associated genetic imprints, a central conservation target. Early signals of reduced dispersal distances that accompany the Anthropogenic defaunation forecast multiple, cascading effects on plant populations.
Specifying when and how gain-and loss-framed messages motivate healthy behavior: an integrated approach. In Society for Judgment and Decision Making Series. Perspectives on Framing (Keren, G., ed.), pp. 257-277, Psychology Press 7. Pope, J.P. et al. (2018) Starting off on the best foot: a review of message framing and message tailoring, and recommendations for the comprehensive messaging strategy for sustained behavior change.
Understanding how ecosystem services interact to support crop yield is essential for achieving food security. Here we evaluate the interactions among biotic pest regulation, pollination, and nutrient cycling. We found only 16 studies providing 20 analyses of two-way interactions. These studies show that multiple services limit crop yield simultaneously. Complementary effects (no interactions) between ecosystem services were the most common, followed by synergistic effects (positive interactions), while evidence for negative interactions was weak. Most studies evaluated two levels of service delivery, thus did not quantify the functional response of crop yield. Although this function is expected to be non-linear, most studies assume linear relations. We conclude that the lack of evidence for negative interactions has important implications for agricultural management.
Declining biodiversity and ecosystem functions put many of nature’s contributions to people at risk. We review and synthesize the scientific literature to assess 50-y global trends across a broad range of nature’s contributions. We distinguish among trends in potential and realized contributions of nature, as well as environmental conditions and the impacts of changes in nature on human quality of life. We find declining trends in the potential for nature to contribute in the majority of material, nonmaterial, and regulating contributions assessed. However, while the realized production of regulating contributions has decreased, realized production of agricultural and many material commodities has increased. Environmental declines negatively affect quality of life, but social adaptation and the availability of substitutes partially offset this decline for some of nature’s contributions. Adaptation and substitutes, however, are often imperfect and come at some cost. For many of the contributions of nature, we find differing trends across different countries and regions, income classes, and ethnic and social groups, reinforcing the argument for more consistent and equitable measurement.
23 24 25 *ManuscriptHowever we found significant reductions in seedling recruitment outside the canopy, effective 42 recruitment rate, and delayed negative effects on seedling vigour in populations hosting small-to 43 medium-sized lizard species. Extirpation of large seed-dispersers did not cause substantial 44 reductions in quantitative components of seed dispersal, but determined declines in qualitative 45 aspects critically affecting dispersal effectiveness. Our study highlights the importance of 46 examining all components of the dispersal/recruitment process to properly document the 47 regeneration outcomes of plants in defaunated, downsized ecological scenarios. 48
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