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41.
Daniel J. van der Post Bas Ursem Paulien Hogeweg 《Behavioral ecology and sociobiology》2009,63(11):1643-1658
We study how learning is shaped by foraging opportunities and self-organizing processes and how this impacts on the effects
of “copying what neighbors eat” on multiple timescales. We use an individual-based model with a rich environment, where group
foragers learn what to eat. We vary foraging opportunities by changing local variation in resources, studying copying in environments
with pure patches, varied patches, and uniform distributed resources. We find that copying can help individuals explore the
environment by sharing information, but this depends on how foraging opportunities shape the learning process. Copying has
the greatest impact in varied patches, where local resource variation makes learning difficult, but local resource abundance
makes copying easy. In contrast, copying is redundant or excessive in pure patches where learning is easy, and mostly ineffective
in uniform environments where learning is difficult. Our results reveal that the mediation of copying behavior by individual
experience is crucial for the impact of copying. Moreover, we find that the dynamics of social learning at short timescales
shapes cultural phenomena. In fact, the integration of learning on short and long timescales generates cumulative cultural
improvement in diet. Our results therefore provide insight into how and when such processes can arise. These insights need
to be taken into account when considering behavioral patterns in nature.
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Daniel J. van der PostEmail: |
42.
John R. Post Hillary G. M. Ward Kyle L. Wilson George L. Sterling Ariane Cantin Eric B. Taylor 《Conservation biology》2022,36(3):e13783
Use of extensive but low-resolution abundance data is common in the assessment of species at-risk status based on quantitative decline criteria under International Union for Conservation of Nature (IUCN) and national endangered species legislation. Such data can be problematic for 3 reasons. First, statistical power to reject the null hypothesis of no change is often low because of small sample size and high sampling uncertainty leading to a high frequency of type II errors. Second, range-wide assessments composed of multiple site-specific observations do not effectively weight site-specific trends into global trends. Third, uncertainty in site-specific temporal trends and relative abundance are not propagated at the appropriate spatial scale. A common result is the propensity to underestimate the magnitude of declines and therefore fail to identify the appropriate at-risk status for a species. We used 3 statistical approaches, from simple to more complex, to estimate temporal decline rates for a designatable unit (DU) of rainbow trout in the Athabasca River watershed in western Canada. This DU is considered a native species for purposes of listing because of its genetic composition characterized as >0.95 indigenous origin in the face of continuing introgressive hybridization with introduced populations in the watershed. Analysis of abundance trends from 57 time series with a fixed-effects model identified 33 sites with negative trends, but only 2 were statistically significant. By contrast, a hierarchical linear mixed model weighted by site-specific abundance provided a DU-wide decline estimate of 16.4% per year and a 3-generation decline of 93.2%. A hierarchical Bayesian mixed model yielded a similar 3-generation decline trend of 91.3% and the posterior distribution showed that the estimate had a >99% probability of exceeding thresholds for an endangered listing. We conclude that the Bayesian approach was the most useful because it provided a probabilistic statement of threshold exceedance in support of an at-risk status recommendation. 相似文献