Explaining outputs determined algorithmically by machines is one of the most pressing and studied problems in Artificial Intelligence (AI) nowadays, but the equally pressing problem of using AI to explain outputs determined by humans is less studied. In this paper we advance a novel methodology integrating case-based reasoning and computational argumentation from AI to explain outcomes , determined by humans or by machines, indifferently, for cases characterised by discrete (static) features and/or (dynamic) stages. At the heart of our methodology lies the concept of arbitrated argumentative disputes between two fictitious disputants arguing, respectively, for or against a case's output in need of explanation, and where this case acts as an arbiter. Specifically, in explaining the outcome of a case in question, the disputants put forward as arguments relevant cases favouring their respective positions, with arguments/cases conflicting due to their features, stages and outcomes, and the applicability of arguments/cases arbitrated by the features and stages of the case in question. We in addition use arbitrated dispute trees to identify the excess features that help the winning disputant to win the dispute and thus complement the explanation.We evaluate our novel methodology theoretically, proving desirable properties thereof, and empirically, in the context of primary legislation in the United Kingdom (UK), concerning the passage of Bills that may or may not become laws. High-level factors underpinning a Bill's passage are its contentagnostic features such as type, number of sponsors, ballot order, as well as the UK Parliament's rules of conduct. Given high numbers of proposed legislation (hundreds of Bills a year), it is hard even for legal experts to explain on a large scale why certain Bills pass or not. We show how our methodology can address this problem by automatically providing high-level explanations of why Bills pass or not, based on the given Bills and their content-agnostic features.
When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989-2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads' marshland breeding areas. Our results showed density-dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long-term time series to identify shifts in population dynamics coincident with the advent of population decline.
Aim: Considerable controversy exists over the nature of the "Biodiversity Crisis."While some studies suggest declining diversity, others suggest no loss on average.Population declines necessarily precede species loss and may therefore be a more sensitive metric. We examine trends in abundances to test the hypotheses: (1) losses are experienced disproportionately by some taxa, in particular amphibians; (2) positive trends in alien or unexploited species mask declines in native or exploited species, respectively; (3) populations are becoming more unstable, and variances of withinpopulation growth rates are increasing. Location: Freshwater and terrestrial habitats in North America and Europe.Methods: We analysed abundances of 4,343 population time series of 983 species of temperate amphibians, birds, bony fishes, reptiles and mammals from 1970 to 2014.Population mean trends were estimated using a state-space model to account for observation error, and then, linear mixed-effects models were used to test mean differences among groups. As a measure of instability, trends over time in variance of population growth rates were analysed using a Breusch-Pagan test for heteroscedacity, and integrated across populations using meta-analysis.Results: Mean trends for amphibians suggested a systematic decline, whereas birds, reptiles and mammals were increasing, on average, and freshwater fishes showed no net change in general. Origin and exploitation status did not explain the mean patterns. Large-bodied birds and range-restricted mammals exhibited stronger increases compared to their counterparts. For all taxonomic groups, population fluctuations have been increasing overall. Main conclusions:Addressing amphibian declines should be a priority in temperate regions. Comparatively, the lack of broad declines in the other vertebrate classes is promising and not attributable to increases in alien or non-exploited species. Yet, caution remains warranted given that patterns of increasing variance suggested that populations are generally becoming more unstable, even in temperate, developed nations, with arguably the strongest environmental regulations. K E Y W O R D Samphibian declines, biodiversity crisis, ecological instability, population trends, temperate biodiversity, vertebrate conservation | 1373 LEUNG Et aL.
Ambitious global conservation targets have been set to manage increasing threats to amphibians. Ex situ institutions (broadly, 'zoos') are playing an expanding role in meeting these targets. Here, we examine the extent to which zoos house species representing the greatest overall conservation priority by testing how eight variables relating to extinction risk -International Union for the Conservation of Nature status, habitat specialization, obligate stream breeding, geographic range size, body size and island, high-altitude and tropical endemism -vary between amphibian species held in zoos and their close relatives not held in zoos. Based on 253 species found in zoos that could be confidently paired with close relatives not in zoos, and in contrast to reported patterns for birds and mammals, we find that amphibians currently held in zoos are equally as threatened as their close relatives not found in zoos. This result is entirely driven by the inclusion of data on species holdings from Amphibian Ark (AArk), an organization that helps to coordinate conservation activities in many 'non-traditional' institutions, as well as in 'traditional' commercial zoos. Such networks of small non-traditional institutions thus make meaningful contributions to ex situ conservation, and the establishment of other taxa-specific organizations modelled on AArk might be considered. That said, our results indicate that the ex situ network is still not prioritizing range-restricted habitat specialists, species that possess greater overall extinction risk in the near future. We strongly encourage zoos to continue increasing their holdings of amphibian species, but to pay greater attention to these species of particular conservation concern.
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