Llewellyn C. Foxcroft

Hitting the right target: taxonomic challenges for, and of, plant invasions.

Taxonomic resources are essential for the effective management of invasive plants because biosecurity strategies, legislation dealing with invasive species, quarantine, weed surveillance and monitoring all depend on accurate and rapid identification of non-native taxa, and incorrect identifications can impede ecological studies. On the other hand, biological invasions have provided important tests of basic theories about species concepts. Modern taxonomy therefore needs to integrate both classical and new concepts and approaches to improve the accuracy of species identification and further refine taxonomic classification at the level of populations and genotypes in the field and laboratory.

Plant Invasions in Protected Areas

There are numerous excellent volumes on the topic of biological invasions, some of which deal with conservation-related issues to varying degrees. Almost 30 years since the last global assessment of alien plant invasions in protected areas during the SCOPE programme of the 1980s, the present book aims to provide a synthesis of the current state of knowledge of problems with invasive plants in protected areas. To set the scene we outline some of the major challenges facing the field of invasion biology. We discuss the extent and dimensions of problems that managers of protected areas deal with and what can be learnt from research and management interventions conducted in protected areas. A virtual tour through different regions of the world sheds light on the rapidly growing knowledge L.C. Foxcroft (*) Conservation Services, South African National Parks, Private Bag X402, Skukuza 1350, South Africa Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa e-mail: Llewellyn.foxcroft@sanparks.org D.M. Richardson Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa e-mail: rich@sun.ac.za P. Pyšek Department of Invasion Ecology, Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice CZ 252 43, Czech Republic Department of Ecology, Faculty of Science, Charles University in Prague, CZ 128 44 Viničná 7, Prague 2, Czech Republic e-mail: pysek@ibot.cas.cz P. Genovesi ISPRA, Institute for Environmental Protection and Research, Via V. Brancati 48, I-00144 Rome, Italy Chair IUCN SSC Invasive Species Specialist Group, Rome, Italy e-mail: piero.genovesi@isprambiente.it L.C. Foxcroft et al. (eds.), Plant Invasions in Protected Areas: Patterns, Problems and Challenges, Invading Nature Springer Series in Invasion Ecology 7, DOI 10.1007/978-94-007-7750-7_1,

Plant invasion science in protected areas: progress and priorities

Invasive alien species are a major problem for managers of protected areas (PAs) worldwide. Until the 1980s biological invasions were widely considered to be largely confined to anthropogenically disturbed sites and the widespread disruption of ecosystems in PAs by invasive species was not globally perceived as a major threat. A working group of the SCOPE program on biological invasions in the 1980s showed that PAs are not spared from major disruptive effects of invasions. Early research focused on descriptive studies of the extent to which PAs were invaded. More recent research explored drivers of invasion, and in the last decade much work has focused on understanding the impacts of invasions. We review the current understanding of alien plant invasions in PAs, focusing on four themes: (1) the status and macroecological patterns of alien plant invasions; (2) the threats that invasive alien plants (IAPs) pose and the impacts detected to date; (3) the current focus of invasion science in PAs; and (4) research priorities for advancing science-based management and policy. Of a sample of 59 widespread IAP species from a representative sample of 135 PAs globally, trees make up the largest proportion (32%), followed by perennial herbs (17%) and shrubs (15%). About 1857 papers have been published on alien species in PAs; 45% have focused on alien plants. Some textbook examples of impacts by IAPs originate from PAs, illustrating the severe threat to the core function of PAs. Impacts have been quantified at the species and community levels through the displacement and alteration of habitats. In some cases, native species abundance, diversity and estimated species richness have been altered, but reversed following control. At an ecosystem level, invasive plants have radically altered fire regimes in several PAs, in some cases causing regime shifts and transforming woodlands or savannas to grasslands. Invasions have also had a major impact on nutrient cycles. Protected areas are performing an increasingly important part of the global response to stem the rate of environmental change. Despite this, integrated efforts involving science, management and policy that are sufficiently resourced to generate insights on the status and dynamics of IAPs in PAs are insufficient or even lacking. Such efforts are needed to pave the way for monitoring trends, revising legislation and policies, and improving management interventions to reduce the extent and magnitude of impacts of invasive plants in PAs. While policy instruments to support management of non-native species date back to the 1930s, there has been a substantial increase in legislative support and general awareness since the early 2000s. Still, opportunities to improve research for PAs need to be created. Towards this goal, the establishment of a global PA research network could provide a unique vehicle to explore questions across species or functional groups and systems, at a scale currently beyond existing abilities. Developing an integrated global database with standardized, quantitative information could form part of such a networks function.

The Role and Value of Conservation Agency Research

Governments charge their conservation agencies to safeguard biodiversity through protected areas and threat mitigation. Increasingly, conservation management and policy need to be supported by rigorous evidence provided by science. As such, institutional arrangements should consider and enable effective scientific research and information dissemination. What role can in-house agency research play in responding to this challenge? We examined the research capabilities of three conservation agencies from Australia, South Africa, and United States. Seven indicators were used to characterize the reliability and relevance of agency research. We found similarities among agencies in their patterns of peer-reviewed publication, cultures of research collaboration, and tendencies to align research with organizational objectives. Among the many and diverse activities that constitute the role of a contemporary agency researcher, we emphasize two key research dimensions: reliability, achieved through peer-reviewed research output, and relevance, achieved through active stakeholder engagement. Amid increasingly challenging realities for conservation of ecosystems, agency science functions are vital to providing the evidence base required for effective management and policy development.

Genetic analysis shows low levels of hybridization between African wildcats (Felis silvestris lybica) and domestic cats (F. s. catus) in South Africa

Hybridization between domestic and wild animals is a major concern for biodiversity conservation, and as habitats become increasingly fragmented, conserving biodiversity at all levels, including genetic, becomes increasingly important. Except for tropical forests and true deserts, African wildcats occur across the African continent; however, almost no work has been carried out to assess its genetic status and extent of hybridization with domestic cats. For example, in South Africa it has been argued that the long-term viability of maintaining pure wildcat populations lies in large protected areas only, isolated from human populations. Two of the largest protected areas in Africa, the Kgalagadi Transfrontier and Kruger National Parks, as well as the size of South Africa and range of landscape uses, provide a model situation to assess how habitat fragmentation and heterogeneity influences the genetic purity of African wildcats. Using population genetic and home range data, we examined the genetic purity of African wildcats and their suspected hybrids across South Africa, including areas within and outside of protected areas. Overall, we found African wildcat populations to be genetically relatively pure, but instances of hybridization and a significant relationship between the genetic distinctiveness (purity) of wildcats and human population pressure were evident. The genetically purest African wildcats were found in the Kgalagadi Transfrontier Park, while samples from around Kruger National Park showed cause for concern, especially combined with the substantial human population density along the parks boundary. While African wildcat populations in South Africa generally appear to be genetically pure, with low levels of hybridization, our genetic data do suggest that protected areas may play an important role in maintaining genetic purity by reducing the likelihood of contact with domestic cats. We suggest that approaches such as corridors between protected areas are unlikely to remain effective for wildcat conservation, as the proximity to human settlements around these areas is projected to increase the wild/domestic animal interface. Thus, large, isolated protected areas will become increasingly important for wildcat conservation and efforts need to be made to prevent introduction of domestic cats into these areas.

The Bottom Line: Impacts of Alien Plant Invasions in Protected Areas

Phrases like “invasive species pose significant threats to biodiversity…” are often used to justify studying and managing biological invasions. Most biologists agree that this is true and quantitative studies support this assertion. Protected areas are the foundation of conservation initiatives in many parts of the world, and are an essential component of an integrated approach to conserving biodiversity and the associated ecosystem services. The invasion of alien plants constitutes a substantial and growing threat to the ability of protected areas to provide this service. A large body of literature describes a range of impacts, but this has not been assessed within the context of protected areas. We do not aim to review the state of knowledge of impacts of invasive plants; rather, we collate examples of work that has been carried out in protected areas to identify important patterns, trends and generalities. We also discuss the outcomes of various studies that, while not necessarily undertaken in protected areas, are likely to become important for protected areas in the future. We discuss the range of impacts under five broad headings: (i) species and communities; (ii) ecosystem properties; (iii) biogeochemistry and ecosystem dynamics; (iv) ecosystem services; and (v) economic impacts.

Threats to Paradise? Plant Invasions in Protected Areas of the Western Indian Ocean Islands

The islands of the Western Indian Ocean are well known for their unique biodiversity. However, much of the native habitat has been destroyed and the remainder is threatened by invasive alien species. In this review we assessed the different protected area systems, synthesised the history of invasive alien plants and actions against them, and compared contrasting approaches in habitat management across the different island groups. Of the total terrestrial area of the Western Indian Ocean Islands, a third is under formal protection (defined as all six IUCN categories of protected areas), with the proportion of protected areas and conservation status differing substantially between the islands. The awareness of the problems related to protected areas and specific invasive alien plant control actions, and which are supported by official government strategic documents, are further developed in Mauritius-Rodrigues, La Reunion, and Seychelles, but are still to be developed for the Comoros archipelago. We discuss the different approaches to management across the islands, the varying habitat types, fragmentation and degree of invasion. Invaded habitats are being managed by a range of approaches, including restoration, re-creation or inclusion as a novel ecosystem. We conclude by suggesting improvements in the protected area system in the Western Indian Ocean Islands, including priority actions that are necessary to prevent further invasion and control of invasive alien species already in the region.

Invasive alien plants in protected areas: Threats, opportunities, and the way forward

The potential threats posed by biological invasions are widely appreciated, but the state of knowledge and level of management of invasive alien plants in protected areas differs considerably across the world. Research done on nature reserves as part of the international SCOPE programme on biological invasions in the 1980s showed the vulnerability of natural or undisturbed areas to invasions. Subsequent work, including the chapters in this book, shows the serious situation regarding plant invasions that prevails in many protected areas. Many invasive plants have, or have the potential to, greatly lessen the potential of protected areas to achieve the things they were proclaimed to do – provide refugia for species, habitats and the ecosystem services that they sustain. This brief synthesis discusses some emerging insights from protected areas of varying kinds and sizes, from the Azores, Australia, Chile, East and South Africa, Europe, Galapagos, India, Mediterranean Islands, New Zealand, Pacific Islands and Hawaii, Southern Ocean Islands, United States of America and the Western Indian Ocean Islands. Work in some protected areas has led to well-developed management and policy frameworks. In others, important insights have emerged on invasion mechanisms and the impacts of invasions. Although there is awareness of invasive alien plants in most of the 135 protected areas mentioned in this volume, better and more focused actions are urgently needed. This requires, among other things, improved capacity to prevent invasions and to react promptly to new incursions, and increasing efforts to manage well-established invasive species. Research to improve the understanding of invasion dynamics is essential. Full species lists are available only for a group of well-known protected areas. Updating species lists and distribution data is crucial for successful long-term management, as are collaborative networks, research groups, volunteers, and improved accessibility to resources such as online databases. Efforts to lessen the science-management divide are especially important in protected areas. One reason is that managers are usually required to implement invasive alien plant control programmes as part of general protected area management activities, and in many cases lack the knowledge and support for effective science-based management solutions. Overcoming this barrier is not trivial and will require partnerships between local, municipal, regional and national-level organizations and international non-profit NGOs and donor organisations.

Icons in Peril: Invasive Alien Plants in African Protected Areas

Protected areas in Africa are global conservation icons, attracting millions of tourists a year. However, these areas are being threatened by a growing human population making increasing demands on the natural capitol being conserved. Moreover, global environmental change, of which biological invasions are a key concern, pose significant threats to the function of ecosystems and their constituents. Other than in a few regions, primarily in South Africa, little is known about alien plant invasions in protected areas across the continent. In order to present a first approximation of the threat of plant invasions to protected areas across Africa, we present the information we could find by drawing on published literature, grey literature and personal observations. We also present six case studies from prominent protected areas across Kenya, Tanzania and South Africa. These case studies aim to illustrate what is known in different regions and the key concerns and management approaches, thereby providing examples that may facilitate shared learning. Where information is available it suggests that some species are likely to be widespread, impacting severely on indigenous species diversity. If protected areas are to be successful in carrying out their mandate of biodiversity conservation, and increasingly, revenue creation, long-term management of invasive plants is essential. However, in developing countries, which characterise much of Africa, resources are severely lacking. Where funds are available for conservation these are often channelled to other aspects of protected area management, such as anti-poaching. Protected areas in Africa include a number of unique attributes that can provide natural laboratories for research on basic ecological principles of invasions, while the research can, in turn, contribute directly to the needs of the protected area agencies.

Plant invasions in protected areas: Outlining the issues and creating the links

There are numerous excellent volumes on the topic of biological invasions, some of which deal with conservation-related issues to varying degrees. Almost 30 years since the last global assessment of alien plant invasions in protected areas during the SCOPE programme of the 1980s, the present book aims to provide a synthesis of the current state of knowledge of problems with invasive plants in protected areas. To set the scene we outline some of the major challenges facing the field of invasion biology. We discuss the extent and dimensions of problems that managers of protected areas deal with and what can be learnt from research and management interventions conducted in protected areas. A virtual tour through different regions of the world sheds light on the rapidly growing knowledge base in different socio-geographical settings, and applies such insights to the problems that managers face. We hope that this book captures the core concerns and creates the critical links that will be needed if the growing impacts of alien plant invasions on protected areas are to be managed effectively. We also aim to promote the role of protected areas as leaders and catalysts of global action on invasive species, and key study areas for basic and applied invasion science.