Reproduction is undeniably key to the survival of all species on earth. Technology aside, the study of reproductive processes in animal species remains dauntingly broad, ranging though the details of gametogenesis, fertilisation and the subsequent processes of embryonic development, growth and sexual differentiation, endocrinology and aspects of behaviour and brain function. As if this list were not broad enough, modern scientific advances have enabled us to drill down into the intricate details of gene expression, protein synthesis and the immune system as it affects each of the processes mentioned above. Importantly, animals evolve and adapt to their environment to optimize fitness, and the science of understanding these interactions has led to the realisation that phenomena such as temperature, photoperiod and seasonality have massive impacts on reproductive function. It is increasingly realised that environmental changes, both global and local, can affect the health and wellbeing of animals and humans alike during their entire life and even beyond (Gluckman et al. 2007; Jablonka and Raz 2009). One outstanding example in this category includes the realisation that epigenetics represent a profound, but hitherto rather unsuspected, influence in responses to environmental change. Grandparent’s smoking behaviour and also the quality of their diet is now known to influence the body mass index of grandchildren through sex-specific germ-line inheritance mechanisms (Pembrey et al. 2006), and transgenerational changes in the behaviour and reproductive success of laboratory animals are induced by the action of endocrine disrupting chemicals (Anway et al. 2006a, b). Given these recent findings, what are the implications for reproductive success, long-term health and evolutionary adaptations in the face of climate change? Relatively few researchers have considered the relevance of these recent developments to wildlife, especially as they are now thought to involve not only direct modifications of the genome through DNA and chromatin methylation, regarded as “epigenetic” modifications (Turner 2009, 2011), but also non-genomic “soma-to-soma” inheritance mechanisms that do not require direct modification of the genome. In fact, it is worth quoting a relevant sentence from Jablonka’s review (Jablonka 2012) where she goes so far as stating that:

…it is safe to maintain that, as far as our idea of heredity is concerned, the view that inherited differences must involve differences in DNA base sequence is now recognized to be wrong.

Realisation that there is more to inheritance than the strict confines of a DNA sequence has meant there has been an explosion of relevant studies over the last decade. Incredibly, a literature search for papers in PubMed using the terms “epigenetics” and “environment”, resulted in 648 references, of which only a single one was published prior to the year 2000. Adding the word “evolution” retrieved 51 references, and it is interesting that a few of these articles explicitly suggested that environmental changes, including climate change, might induce adaptations and evolutionary changes through epigenetic effects (Silvestre et al. 2012; Crews and Gore 2012). As the combination of climate change, epigenetics and adaptation provides an important and overarching context with links to most other aspects of reproductive sciences, we were keen to include an authoritative overview of climate change and reproduction here in this book (Chap. 3; Cynthia Carey) to understand some of its consequences.

The relevance of research in epigenetics, and its close relative “genomic imprinting”, to reproduction, especially in terms of foetal–maternal interactions and their pre- and post-conception influences on phenotypic development, means that epigenetic effects are increasingly regarded as significant modulators of reproductive success. Given that the uterine environment in which a mammalian embryo develops can influence the onset of diabetes, heart disease and arteriosclerosis in later adult life (Henry et al. 2012; Turner 2012), what might be the long-term effects of producing and growing embryos in culture dishes? In view of changing environmental conditions, we wanted to explore and explain the ways that factors such as food availability and quality and the presence in the environment of certain chemicals with hormone-like activities might be affecting species (Chap. 6; Agustin Fernández et al. and Chap. 4; Emmelianna Kumar and William Holt). These are major subjects in their own right but the extensive degree of linkage among the topics is becoming increasingly clear. Genomics is another closely related and rapidly advancing field that is yielding insights into the way in which the genome functions. What were previously regarded as sequences of non-functional DNA, often regarded as “junk” DNA, are now known to contain unsuspected but functional sequences (e.g. enhancers; Zhang et al. 2013) with specific roles in controlling gene expression. Thus, the integration of advanced genomic insights into conservation programmes is becoming more important (Chap. 5; Warren Johnson and Klaus Koefli).

As part of the “big picture” we also wanted to review progress with one of the most successful technologically-managed wildlife conservation actions of the last few decades, namely the case of the black-footed ferret (Mustela nigripes). Once considered extinct in the USA until a small remnant population was discovered in 1981, the black-footed ferret has been the focus of an intensive captive breeding programme for reintroduction into its original habitats. Rachel Santymire and her colleagues (Chap. 7) have reviewed this programme for us, and declare that the outcome is rather mixed. Without the initial technological inputs by the late JoGayle Howard and her colleagues (Howard et al. 2003), the species would undoubtedly not have survived. Since 2001, however, continued monitoring of the black footed ferret population has revealed problems caused by inbreeding depression and environmental effects. This is rather disappointing, but this case provides some general lessons about the interface between conservation and reality.

From the outset, one of our major objectives in producing this book has been to present a comprehensive progress report about various wildlife research programmes that involve aspects of reproductive biology. Here we present a set of six chapters that represent a huge variety of species, ranging from corals to elephants. These chapters also show how progress is dependent on well-focused, sustained research programmes. These attributes are well illustrated by studies in the elephant (Janine L. Brown; Chap. 8) and the koala (Steve Johnston and William Holt, Chap. 9), carnivores (Katarina Jewgenow and Nucharin Songsasen; Chap. 10) and the corals (Mary Hagedorn; Chap. 13). Studies of this type are interesting because of the way they eventually extend their scope into areas not originally foreseen. Endocrinology in the elephants is now linking reproduction with body condition, the control of appetite and even shows parallels of relevance to human clinical medicine (i.e., obesity research). Similarly, the problems of semen cryopreservation in marsupials led to the initiation of novel research directions on DNA fragmentation and semen quality in humans and domestic livestock. As a research topic this was almost non-existent before 2000, although it had been explored to a certain extent 10–15 years earlier (Ballachey et al. 1987; Royère et al. 1988, 1991). Studies on carnivores have been substantial and helped to describe new mechanisms (such as the persistence of corpora lutea in Lynx species) over the past 10 years (Katarina Jewgenow; Chap. 10). The importance of integrating laboratory and field studies are well exemplified by the chapters on marine mammals (Janet Lanyon; Chap. 11), amphibians (John Clulow et al.; Chap. 12) and corals (Mary Hagedorn; Chap. 13). These species are under threat from environmental change, the marine mammals mainly from pollution, shipping and even the use of sonar in naval activities (Piantadosi and Thalmann 2004), the corals from ocean acidification and bleaching, and the amphibians from the global spread of the destructive fungal disease, chytridiomycosis. Reproductive monitoring in wild sea mammals had hardly been thought possible a decade ago, but ingenious ways of collecting faecal samples and identifying individual animals have now been developed, using combinations of reproductive technologies and genetic methods that allow samples to be collected and hormones measured. Research by Mary Hagedorn has led to a suitable method for cryopreserving coral cells, so that they can be kept as a genuine genetic resource bank and used to repopulate threatened corals in their marine habitats. Similarly, the amphibian research is multifaceted and is also aimed at being able to maintain cryopreserved gametes, so that live biosecure, and therefore isolated, populations of endangered amphibians can at least receive as much genetic support as possible while treatments to mitigate the chytrid infections and habitat contaminations are being sought.