Defaunation in the Anthropocene

Abstract

onto ecosystem functioning and human well-being. Much remains unknown about 28 this "Anthropocene defaunation"; these knowledge gaps hinder our capacity to 29 predict and limit defaunation impacts. Clearly, however, defaunation is both a 30 pervasive component of the planet's sixth mass extinction, and also a major driver of 31 global ecological change. 32 33In the past 500 years, humans have triggered a wave of extinction, threat, and local 34 population declines that may be comparable in both rate and magnitude to the five 35 previous mass extinctions of Earth's history (1). Similar to other mass extinction events, 36 the effects of this "sixth extinction wave" extend across taxonomic groups, but are also 37 selective, with some taxonomic groups and regions being particularly affected (2). Here, 38we review the patterns and consequences of contemporary anthropogenic impact on 39 terrestrial animals. We aim to portray the scope and nature of declines of both species and 40 abundance of individuals, and examine the consequences of these declines. So profound 41 is this problem, that we have applied the term defaunation to describe it. This recent pulse 42 of animal loss, hereafter referred to as the Anthropocene defaunation, is not only a 43 conspicuous consequence of human impacts on the planet, but also a primary driver of 44 global environmental change in its own right. In comparison, we highlight the profound 45 ecological impacts of the much more limited extinctions, predominantly of larger 46vertebrates, that occurred during the end of the last Ice Age. These extinctions altered 47 ecosystem processes and disturbance regimes at continental scales, triggering cascades of 48 extinction thought to still reverberate today (3, 4). 49The term defaunation, used to denote the loss of both species and populations of 50 wildlife (5), as well as local declines in abundance of individuals, needs to be considered 51 in the same sense as deforestation, a term that is now readily recognized and influential in 52 focusing scientific and general public attention on biodiversity issues (5). However, 53 whilst remote sensing technology provides rigorous quantitative information and 54 compelling images of the magnitude, rapidity and extent of patterns of deforestation, 55 defaunation remains a largely cryptic phenomenon. It can occur even in large protected 56 habitats (6) and, yet, some animal species are able to persist in highly modified habitats, 57 making it difficult to quantify without intensive surveys. 58Analyses of the impacts of global biodiversity loss typically base their 59 conclusions on data derived from species extinctions (1, 7, 8) and typically evaluations of 60 the effects of biodiversity loss draw heavily from small scale manipulations of plants and 61 small sedentary consumers (9). Both of these approaches likely underestimate the full 62 impacts of biodiversity loss. While species extinctions are of great evolutionary 63 significance, declines in the number of individuals in local populations and chan...

Pollen-vegetation richness and diversity relationships in the tropics

“…Pollen grains were counted under 400 × and 1,000 × magnification using Nikon LABOPHOT (Bolivian traps, by WDG) and Nikon Eclipse 50i (Ghanaian traps, by ACMJ) microscopes. Pollen identifications were based on pollen reference collections (University of Leicester, The Open University, University of Amsterdam), pollen atlases and online resources (Bonnefille 1971;Bonefille and Rioellet 1980;Moore et al 1991;Roubik and Moreno 1991;Colinvaux et al 1999;Bush and Weng 2007;Vincens et al 2007;Gosling et al 2013). Target pollen sums (total number of pollen grains counted) for the Bolivian plots were > 100 grains per trap, which resulted in > 2,500 grains per vegetation study plot (Table 1; Fig.…”

“…Biodiversity is widely regarded as important for ecosystem function and services (Hooper et al 2005;Cardinale et al 2012), and consequently the observed loss of biodiversity over recent decades (Benitez-Malvido and Martinez-Ramos 2003;Stuart et al 2004;Dirzo et al 2014) has resulted in many efforts being made to preserve biodiversity. For example, actions have targeted the preservation of individual species (Teich et al 2005), the establishment of areas of conservation priority (Myers et al 2000) and the promotion of re-wilding at a continental scale (Navarro and Pereira 2012).…”

Trait‐based approaches to analyze links between the drivers of change and ecosystem services: Synthesizing existing evidence and future challenges

“…Direct drivers of change include land‐use change, climate change, invasive alien species, overexploitation, and pollution (Pereira, Navarro, & Martins, 2012; Vitousek, Mooney, Lubchenco, & Melillo, 1997). The loss of biodiversity may alter ecosystem functioning and the delivery of ecosystem services, with major repercussions on human well‐being (Balvanera et al., 2006; Dirzo et al., 2014; Hanski et al., 2012; Mace, Norris, & Fitter, 2012). Although biodiversity is assumed to be critical for providing ecosystem services (Cardinale et al., 2012; De Bello et al., 2010; Harrison et al., 2014), our understanding about the links between biodiversity and individual ecosystem services remains incomplete (Balvanera et al., 2014; Bennett et al., 2015; Isbell et al., 2011; Suding et al., 2008).…”

Buffer zone use by mammals in a Cerrado protected area

“…The persistence of several species worldwide has been threatened by current levels of anthropogenic disturbances in natural environment to the point that the rate of species extinction is already comparable to mass extinction events of the geological past (Dirzo et al 2014). Among mammals, one in each four species is already threatened, mainly due to habitat loss and degradation.…”