The impact of large animal extinctions on nutrient fluxes in early river valley civilizations

Doughty, Christopher E.; Wolf, Adam; Malhi, Yadvinder

doi:10.1890/es13-00221.1

Cited by 17 publications

(17 citation statements)

References 71 publications

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“…The MBMI may indicate that hunting down a size gradient has occurred over time across the region, which has been reported from studies at individual sites (e.g., Gill et al 2012. The size of remaining mammalian fauna in the forests today will likely be generally smaller; this has probably had multiple effects on ecosystem function , including changes in forest composition (Beaune et al 2013, Effiom et al 2013) and nutrient cycling (Doughty et al 2013a, b, Wolf et al 2013. Trends in both MBMI and OPI need to be interpreted carefully, especially when data from different types of hunting, e.g.…”

Section: Two Offtake Indicatorsmentioning

confidence: 89%

Indicators for wild animal offtake: methods and case study for African mammals and birds

Ingram¹,

Coad²,

Collen³

et al. 2015

E&S

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ABSTRACT. Unsustainable exploitation of wild animals is one of the greatest threats to biodiversity and to millions of people depending on wild meat for food and income. The international conservation and development community has committed to implementing plans for sustainable use of natural resources and has requested development of monitoring systems of bushmeat offtake and trade. Although offtake monitoring systems and indicators for marine species are more developed, information on harvesting terrestrial species is limited. Building on approaches developed to monitor exploitation of fisheries and population trends, we have proposed two novel indicators for harvested terrestrial species: the mean body mass indicator (MBMI) assessing whether hunters are relying increasingly on smaller species over time, as a measure of defaunation, by tracking body mass composition of harvested species within samples across various sites and dates; and the offtake pressure indicator (OPI) as a measure of harvesting pressure on groups of wild animals within a region by combining multiple time series of the number of harvested individuals across species. We applied these two indicators to recently compiled data for West and Central African mammals and birds. Our exploratory analyses show that the MBMI of harvested mammals decreased but that of birds rose between 1966/1975 and 2010. For both mammals and birds the OPI increased substantially during the observed time period. Given our results, time-series data and information collated from multiple sources are useful to investigate trends in body mass of hunted species and offtake volumes. In the absence of comprehensive monitoring systems, we suggest that the two indicators developed in our study are adequate proxies of wildlife offtake, which together with additional data can inform conservation policies and actions at regional and global scales.

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Section: Two Offtake Indicatorsmentioning

confidence: 89%

Indicators for wild animal offtake: methods and case study for African mammals and birds

Ingram¹,

Coad²,

Collen³

et al. 2015

E&S

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“…Where floodplains or parts of them still exist in protected areas, however, they act as the foci for much ecological activity. Recent modelling has suggested that large populations of mammals (Table ) were formerly responsible for redistributing large quantities of nutrients from floodplains to the surrounding landscapes (Doughty, Wolf & Malhi (,b) and that such landscapes where semblances of populations of large wild mammals still persist in national parks and game reserves were therefore much more nutrient‐rich than they are now. Of course, where the landscapes have been converted to agriculture and settlement, the use of inorganic fertiliser has vastly increased the amounts of nutrients in circulation, probably to at least an order of magnitude greater than under any natural conditions (Vitousek et al ., ; Smith, Alexander & Schwarz, ; Moss et al ., ).…”

Section: Shallow Lakes and Large Mammalsmentioning

confidence: 98%

Mammals, freshwater reference states, and the mitigation of climate change

Moss

2015

Freshwater Biology

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Summary Freshwater habitats have been severely altered by human activities, and legislation has variously been passed requiring assessment of the damage in preparation for its repair. The current condition is generally measured against a reference state, which may be ‘natural’, meaning pre‐Columbian, in the United States, pre‐European in Australia or, in Europe, a habitat with ‘no, or negligible human influence’. Such standards are mostly unachievable at present because of a current economic philosophy that promotes exploitation of nature, but they are also nebulous. Even pristine habitats naturally change, so that there can be no single immutable reference state. Nonetheless, in Europe at least, the concept of the reference state has been particularly compromised, compared with the aspirations of the legislation. Apart from a very liberal approach to setting reference standards, there has been a major omission in contemplating the general nature of the reference state. The potential former roles of large herbivorous land mammals, such as horses, bovines, deer and, early in the Holocene, elephants and rhinoceri, and their predators, in nutrient transfers, have been ignored. The effects of such large mammals, particularly in influencing lakes, are assessed in the light of major losses of much of the Pleistocene fauna during the hunter‐gatherer phase of human colonisation, and then subsequent near‐complete attrition when agriculture, husbandry and forestry converted the majority of biomes to ‘anthromes’. Animals, and particularly large herbivorous mammals, transfer nutrients across catchments. Large mammals are likely to have maintained a state of turbid water and algal blooms in pristine, poorly flushed, shallow floodplain lakes. In contrast, we currently perceive these to be in a reference state when dominated by submerged plant communities in clear water. Although of conceptual interest, this may seem to have little practical relevance because the reference state has become a pragmatic and political construct rather than an ecological one. I counter such a view by arguing that mitigation of climate change must require replacement of substantial carbon sinks that have been lost, that ecological sinks within restored biomes are likely to be the most effective and that restoration of such systems must involve the important roles of large mammals, with the implications these have for our concepts of lake restoration.

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“…The presence of an intact vertebrate fauna, accordingly, is vitally important in maintaining arthropod and other invertebrate diversity. Their presence, in addition, is important in maintaining soil nutrients and seed dispersal with flow-on effects for forest structure-and the complex of resources these present to the invertebrates (Doughty et al, 2013). There is some evidence that invertebrates decline with defaunation of megafauna due to the impact on understory vegetation and resource availability (Lamperty, Zhu, Poulsen, & Dunham, 2019) but more broadly based work is needed.…”

Section: The Importance Of Vertebrates?mentioning

confidence: 99%

Invertebrates and the complexity of tropical ecosystems

2020

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It has been estimated that there are seven million terrestrial arthropod species on Earth consisting of 6.1 million species of insects, 1.5 million of which are beetles. Tropical forests hold a majority of these species, yet few such places have been adequately sampled for alpha diversity, and there remains even more uncertainty about beta diversity. From an ecological point of view, it is the functional role of organisms within ecosystems that is the particular focus. It has been customary to classify invertebrates within ecosystems in terms of their trophic roles, but it is also useful to consider their roles in networks. In broad terms, we can classify these networks on the grounds of their basal resources. Those based directly on the photosynthetic products of plants are so‐called “green” food webs, and those based on dead and dying plant material are “brown” food webs. Here, we principally discuss the diversity and functional roles of the invertebrates in tropical terrestrial ecosystems. New sampling and analytical techniques, an expanded set of focal taxa, and an enhanced concern with interactions and processes hold the promise of a productive future for invertebrate studies in the tropics. These will not only add to general understanding of the dynamics of tropical ecosystems but will also provide powerful tools for monitoring and responding to environmental change.

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The impact of large animal extinctions on nutrient fluxes in early river valley civilizations

Cited by 17 publications

References 71 publications

Indicators for wild animal offtake: methods and case study for African mammals and birds

Indicators for wild animal offtake: methods and case study for African mammals and birds

Mammals, freshwater reference states, and the mitigation of climate change

Invertebrates and the complexity of tropical ecosystems

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