A meta‐analysis of declines in local species richness from human disturbances

Abstract

There is high uncertainty surrounding the magnitude of current and future biodiversity loss that is occurring due to human disturbances. Here, we present a global meta-analysis of experimental and observational studies that report 327 measures of change in species richness between disturbed and undisturbed habitats across both terrestrial and aquatic biomes. On average, human-mediated disturbances lead to an 18.3% decline in species richness. Declines in species richness were highest for endotherms (33.2%), followed by producers (25.1%), and ectotherms (10.5%). Land-use change and species invasions had the largest impact on species richness resulting in a 24.8% and 23.7% decline, respectively, followed by habitat loss (14%), nutrient addition (8.2%), and increases in temperature (3.6%). Across all disturbances, declines in species richness were greater for terrestrial biomes (22.4%) than aquatic biomes (5.9%). In the tropics, habitat loss and land-use change had the largest impact on species richness, whereas in the boreal forest and Northern temperate forests, species invasions had the largest impact on species richness. Along with revealing trends in changes in species richness for different disturbances, biomes, and taxa, our results also identify critical knowledge gaps for predicting the effects of human disturbance on Earth's biomes.

Biotic homogenization can decrease landscape-scale forest multifunctionality

“…As a result, we have a poor understanding of how multifunctionality relates to biodiversity at the larger spatial scales that are most relevant to ecosystem managers. This question is of particular concern, given recent findings suggesting that humandriven homogenization of communities [loss of β-diversity (18-21)] may be just as widespread as α-diversity declines (22,23).…”

A framework for quantifying the magnitude and variability of community responses to global change drivers

“…However, such comparisons are informative (Winfree et al 2009, Murphy and Romanuk 2012, Tilman et al 2012, Murphy and Romanuk 2014 and experiments are increasingly studying multiple global change drivers in single experiments (Shaw et al 2002). Future studies should focus on what Fig.…”

Changes in phytophagous insect host ranges following the invasion of their community: Long‐term data for fruit flies

“…Biological invasions are considered to be a major threat to biodiversity (Murphy & Romanuk, 2014), partly because invaders can affect the structure of the native community through direct and indirect effects on native species (Strauss, Lau, & Carroll, 2006). Invasive species can interact with native species at different trophic levels, rearranging food webs through species extinctions or by facilitating subsequent invasions (Strauss et al., 2006; Tran, Jackson, Sheath, Verreycken, & Britton, 2015), e.g., through the competitive displacement of native species (Li et al., 2015) or the introduction of pathogens that also attack native species (Roy et al., 2011).…”

“…In some cases, invasive species have beneficial effects on native species (Rodriguez, 2006) but generally invasive species decrease the abundance of native ones (Gurnell, Wauters, Lurz, & Tosi, 2004). Invasive species generally have negative effects on native species richness, of an intensity similar to that for human disturbances, such as land use change and habitat loss (Murphy & Romanuk, 2014). The impact of invasive species on the food webs they invade has been investigated by describing interactions before and after the invasion (Vander Zanden, Casselman, & Rasmussen, 1999).…”