Fragmentation and rapid conversion of forested landscapes to farmland and human settlements in Upper Assam, India has led to the isolation of western hoolock gibbon (Hoolock hoolock) families in fragmented patches of village areas. Many families have perished due to resource scarcity and conflict with development; however, the villages of Barekuri area in Upper Assam have retained a substantial number of gibbon families for many years. We monitored the population (nine families) from 2011 to 2017 and present long-term data on social organisation and its dynamics in Barekuri area. We recorded eight births, nine deaths and four dispersals in the population. Five of the nine deaths were due to electrocution that reduced the population size from 29 individuals in nine groups in 2011 (3.22 ± SD 0.67) to 24 in seven groups in 2017 (3.29 ± SD 0.76), with a mean group size of 3.67 ± SD 0.85 which did not differ over the years. Female inter-birth intervals and ages at first reproduction are comparable with those in wild populations. Both males and females took the opportunity to form groups and breed, and male replacement and female surrogacy indicate flexibility in a pair-bond. Our observations thus support a growing knowledge of variability in the social organisation of gibbons.

Insects are the most abundant and diverse group of animals on Earth. They are critical to ecosystem function in terrestrial and aquatic systems, yet they are one of the most understudied groups of organisms. Only a small proportion of the more than five million insect species have been assessed by the IUCN Red List. For most of these species, there is not enough evidence to know what is happening to their populations. In fact, for most insect species globally, there is very little data available on where they live, how they live and what environmental conditions they need to persist in the long term. A number of threats affect insect biology and life cycles generally, including climate change, habitat clearing, invasive species, use of broad-spectrum pesticides, and pollution of soil and waterways. These threats should be addressed immediately to prevent further declines in insect populations. To understand insects better, greater investment in research and documentation of the world’s insect diversity is urgently needed.

Local awareness and cultural value of threatened species are regarded as integral components of conservation programmes, but pro-environmental attitudes do not necessarily prevent negative human interactions with threatened species. The history of cultural attitudes towards gibbons in China provides an important case study about long-term conservation effectiveness of positive biodiversity values. Animals readily identifiable as gibbons are frequently recorded in Chinese culture from the Zhou Dynasty onward. Gibbons were interpreted as symbols of the supernatural and celebrated in Chinese literature and art. They were also regarded as positive moral exemplars embodying virtuous filial Confucian values, and were equated with the concept of junzi, a noble person who strives after virtue and inspires by example. However, positive cultural associations had little effect in preventing the historical loss of gibbon populations across nearly all of China. Historical records also document exploitation of gibbons for medicinal and other uses, and gibbon declines likely reflect historical conflict with economic demands for local subsistence in marginalised low-income communities. Positive cultural values may therefore be insufficient to prevent species losses if they are outweighed by economic pressures, and awareness may not contribute to positive behavioural change if it does not address drivers of negative human–wildlife interactions.

The conservation status of the taxa in this book is measured using the criteria of the Red List of Threatened Species™. The Red List is overseen by the International Union for Conservation of Nature (IUCN), and categorises species according to extinction risk. This chapter summarises the history of the Red List and explains the criteria used to assess species’ extinction risk, as well as the quality control procedures in place today. This chapter also introduces a new part of the Red List, formalised in 2021: The Green Status of Species, a set of metrics which assess species’ progress towards functional recovery across its range and the impact of conservation actions.

In Chapter 1 it was emphasised that the first cellular life forms to evolve were bacteria, and that photosynthetic bacteria called cyanobacteria released oxygen through photosynthesis and thus set in train the conditions which allowed the many forms of aerobic life to evolve.

Knowing how people perceive and relate to the environment is invaluable to conservation efforts. The mechanisms that drive conservation initiatives are social in nature, and it must be acknowledged that conservation is as much about people as it is the environment and non-human species. This research explored how local communities living on the border of Gunung-Gede Pangrango National Park in West Java, Indonesia perceive the natural environment and the wildlife with which they share the forest. More specifically, the goal was to determine the depth of their knowledge about Javan gibbons (Hylobates moloch) and the threats they face in the wild. Face-to-face, semi-structured interviews were conducted with over 100 people during the months of June through August 2016. Interviews revealed an unexpected narrative. Local people have limited knowledge and information with regard to the forest and its inhabitants. Responses varied between how important people thought protecting the forest was and how crucial the need to expand agriculture is for their personal livelihoods. People also expressed a desire to be more involved in local conservation initiatives. Support from local governments and community engagement is crucial to ensure the success of conservation programmes for Javan gibbons in West Java.

Worldwide, freshwater biodiversity is in decline and increasingly threatened. Fishes are the best-documented indicators of this decline. General threats to persistence include: (1) competition for water, (2) habitat alteration, (3) pollution, (4) invasions of alien species, (5) commercial exploitation and (6) global climate change. Regional faunas usually face multiple, simultaneous causes of decline. Threatened species belong to all major evolutionary lineages of fishes, although families with the most imperilled species are those with the most species (e.g. Cyprinidae, Cichlidae). Independent evaluation of California’s highly endemic (81%) fish fauna for comparison with IUCN results validates the alarm generated by IUCN evaluations. However, IUCN overall evaluation is conservative, because it does not include many intraspecific taxa for which extinction trends are roughly double those at the species level. Dramatic global loss of freshwater fish species is imminent without immediate and bold actions by multiple countries.

Only four terrestrial invertebrate phyla dealt with in this chapter appear in the IUCN Red List of Threatened Species. Three of these phyla are composed of mostly marine animals, but all the listed species of Nemertea and Platyhelminthes are limnoterrestrial, and of the 224 listed annelids, 222 are limnoterrestrial. Conservation issues related to their marine counterparts are discussed in other chapters of this book.

Numerous non-insect limno/terrestrial arthropods appear in the IUCN Red List of Threatened Species. Nearly all arachnids and myriapods are terrestrial, but within Pancrustacea, many taxa can inhabit marine, limnic and terrestrial environments and it is not possible to easily disentangle the numbers of listed species without sorting them species by species. In some cases, as in Malacostraca, the number provided includes species inhabiting either environment, or even cases of amphidromous species that spend part of their life cycle at sea and part in rivers and streams, as is the case of many shrimp species.

Fishes are the original and most diverse group of vertebrates, including over 35,000 of the estimated 69,000 species with backbones. Most marine fishes have large geographic ranges that may provide some protection from extinction, but there are very important exceptions

Western hoolock gibbons (Hoolock hoolock) and eastern hoolock gibbons (Hoolock leuconedys) represent the ape group in India. The seven northeastern states (Assam, Arunachal Pradesh, Meghalaya, Mizoram, Tripura, Nagaland and Manipur) support the entire gibbon population in India, where their distribution is limited to the southern bank of the Dibang–Brahmaputra River system. Rapid loss of habitat, habitat fragmentation and hunting are the major threats to hoolock gibbons in India. The launch of the Indo-US Primate Project provided motivation to conserve the hoolock gibbon in the region. Research, education and awareness, training, capacity building and socioeconomic development programmes, carried out during and after the Indo-US Primate Project, created a healthy environment for the conservation of gibbons in India. Ex-situ conservation practices like rescue and rehabilitation, translocation, conservation breeding programmes and community-based conservation have been the result of collaborations between the government and non-governmental organisations over the past two decades, thus raising new hope for the survival of these species. The recent declaration of protected areas will ensure the long-term survival of the gibbons and its habitats. We feel that all stakeholders should emphasise the development of workable plans for the conservation of gibbons after the COVID-19 pandemic.

Non-marine molluscs stand out as the major animal group under the most severe threat. Among the 8664 mollusc species evaluated for the IUCN Red List (version 2019-1), 300 are considered Extinct out of a total 872 listed Extinct species. However, only ~10% of molluscs have been evaluated and other assessments of the number of extinct species are much higher, 3000 to over 5000, almost exclusively non-marine species. As for most other groups, threats faced by non-marine molluscs are habitat loss, probably the most important, but also impacts of introduced species, exploitation, generally of less concern, and climate change, likely to have serious effects into the future. Oceanic island species, often narrowly endemic, are especially threatened and constitute a high proportion of recorded extinctions. Anthropogenic activities have caused non-marine mollusc extinctions since prehistory, but threats have increased greatly over the last few centuries and will probably continue to increase. Most mollusc species for which a population trend has been evaluated by IUCN are stable or declining; those few that are increasing are primarily introduced and invasive. Most threatened are oceanic island snails, North American and other freshwater bivalves, and the diverse and highly endemic micro-snails of Southeast Asian limestone outcrops.