Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.

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Global effects of land use on local terrestrial biodiversity

Land use and related pressures have reduced local terrestrial biodiversity, but it is unclear how the magnitude of change relates to the recently proposed planetary boundary (“safe limit”). We estimate that land use and related pressures have already reduced local biodiversity intactness—the average proportion of natural biodiversity remaining in local ecosystems—beyond its recently proposed planetary boundary across 58.1% of the world’s land surface, where 71.4% of the human population live. Biodiversity intactness within most biomes (especially grassland biomes), most biodiversity hotspots, and even some wilderness areas is inferred to be beyond the boundary. Such widespread transgression of safe limits suggests that biodiversity loss, if unchecked, will undermine efforts toward long-term sustainable development.

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Has land use pushed terrestrial biodiversity beyond the planetary boundary? A global assessment

Interactions between ants and honeydew-producing hemipteran insects are abundant and widespread in arthropod food webs, yet their ecological consequences are very poorly known. Ant–hemipteran interactions have potentially broad ecological effects, because the presence of honeydew-producing hemipterans dramatically alters the abundance and predatory behaviour of ants on plants. We review several studies that investigate the consequences of ant–hemipteran interactions as ‘keystone interactions’ on arthropod communities and their host plants. Ant–hemipteran interactions have mostly negative effects on the local abundance and species richness of several guilds of herbivores and predators. In contrast, out of the 30 studies that document the effects of ant–hemipteran interactions on plants, the majority (73%) shows that plants actually benefit indirectly from these interactions. In these studies, increased predation or harassment of other, more damaging, herbivores by hemipteran-tending ants resulted in decreased plant damage and/or increased plant growth and reproduction. The ecological consequences of mutualistic interactions between honeydew-producing hemipterans and invasive ants relative to native ants have rarely been studied, but they may be of particular importance owing to the greater abundance, aggressiveness and extreme omnivory of invasive ants. We argue that ant–hemipteran interactions are largely overlooked and underappreciated interspecific interactions that have strong and pervasive effects on the communities in which they are embedded.

https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2006.3701

Ecological consequences of interactions between ants and honeydew-producing insects.

Book Review: 1992. Life in Amber

Bioindicators, as taxa or functional groups, are widely used as indicators of environmental change, specific ecological factors or taxonomic diversity. The use of ecological, environmental and biodiversity indicators, is reviewed here. Although indicator taxa are considered to be generally unreliable as broad indicators of biodiversity, they may serve a useful function in identifying ecological characteristics or monitoring the effects of habitat management. Use of only a narrow range of taxa may be unreliable, and is particularly vulnerable to distortion by a small number of invasive species. Taxa also need to be selected to reflect the specific ecosystem being studied. It is recommended that isopods be used for soil systems (if there is sufficient local diversity), in some areas earthworms or mites may be useable but are generally too difficult to identify to be practically useful. In the ground layer indicator sets could include ants, millipedes, molluscs (snails in particular), ground beetles, harvestmen and gnaphosid spiders. Foliage-inhabiting indicators could comprise ants, chrysomelid leaf beetles, theridiid spiders and arctiid moths. Ants, orthopterans and butterflies may be appropriate for use in open habitats. These basic sets should be supplemented by other taxa where appropriate resources and taxonomic expertise are available.

Terrestrial invertebrates as bioindicators: an overview of available taxonomic groups

Aunque el libro procura tomar varios temas criticos (ecologia, relaciones con plantas, mosaicos), debido a limites de espacio necesariamente excluye otros temas. En parte estos temas se pueden encontrar en libros como The Ants de Holldobler y Wilson (1990) y Ants: Standard methods editado por Agosti et al. (2000). Aun asi, se espera que el libro tenga utilidad por largo tiempo, hasta que los siempre cambiantes temas en biologia de hormigas permitan y favorezcan una segunda edicion, o hasta que otros mirmecologos colegas puedan editar y lanzar un nuevo texto que recoja los muchos cambios que ocurriran en los proximos anos. Sigue a continuacion una breve sinopsis de las partes y capitulos que comprenden el libro.

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Introducción a las hormigas de la región Neotropical

Ants as biological indicators of Wayana Amerindian land use in French Guiana

A review of mosaics of dominant ants in rainforests and plantations.

IBISCA-Panama ("Investigating the BIodiversity of Soil and Canopy Arthropods", Panama module) represents a large-scale research initiative to quantify the spatial distribution of arthropod biodiversity in a Neotropical forest, using a combination of (1) international collaboration, (2) a set of common research questions, and (3) an integrated experimental design. Here, we present the rationale of the programme, describe the study sites, and outline field protocols. In the San Lorenzo Protected Area of Panama, twelve 20 x 20 m sites, all less than 2 km apart, were surveyed for plants and arthropods, from the ground to the upper canopy. Access to the canopy and its fauna was facilitated by fogging, single-rope techniques and a variety of devices such as a canopy crane, the "SolVin-Bretzel" canopy raft, the canopy bubble and Ikos. IBISCA-Panama represented the first attempt to combine these complementary techniques of canopy access in a large-scale investigation. Such techniques provided spatial replication during initial field work performed in September-October 2003. Temporal replication across seasons consisted of subsequent field work of varying intensity during dry, early wet and late wet periods in 2004. Arthropods were surveyed using 14 different protocols targeting the soil, litter, understorey, mid-canopy and upper canopy habitats. These protocols included: WINKLER sifting; BERLESE-TULLGREN; hand-collecting of galls and social insects; fogging; beating; woodrearing; baits; and various types of traps such as pitfall, small and large flight-interception, sticky, light, and Malaise traps. Currently, analyses of arthropod distribution in this forest concentrate on a set of 63 focal taxa representing different phylogenies and lifehistories. IBISCA-Panama may be considered as a model for largescale research programmes targeting invertebrate biodiversity. Its collaborative modus operandi can be applied to answer a variety of pressing ecological questions related to forest biodiversity, as evidenced by the recent development of further IBISCA programmes in other parts of the world.

IBISCA-Panama, a large-scale study of arthropod beta-diversity and vertical stratification in a lowland rainforest: rationale, study sites and field protocols

A. Dejean

Papers

Introducción a las hormigas de la región Neotropical

Ants as biological indicators of Wayana Amerindian land use in French Guiana

A review of mosaics of dominant ants in rainforests and plantations.

IBISCA-Panama, a large-scale study of arthropod beta-diversity and vertical stratification in a lowland rainforest: rationale, study sites and field protocols

A stingless bee nesting inside ant-gardens in French Guiana (Hymenoptera: Apidae)