**4.4 Control of invasive species**

In oceanic islands, as stated, biological invasions can lead to severe large-scale ecosystem alterations. Thus, the eradication of IAS has been a common management practice in island PAs, being widely recommended [23, 96, 99–104].

Eradication of IAS in general is a complex and controversial management action. On islands it is attainable in the early stages of invasion [35], but later it is largely restricted to a few invasive mammals such as rabbits and rats [105] and then, for most species, permanent pest control is the only option.

Most of the already mentioned measures must be applied to the control of IAS. First, the knowledge of the IAS present is fundamental. There are many IAS listed around the world, a study that has been undertaken during the past 50 years or so. The Invasive Species Specialist Group developed a global invasive species database [106], and many countries have regional and national databases, although there is still work to do on this subject.

Coordination between countries and trans-national management plans are required to allow the development of joint actions across geographical areas that go beyond each country's frontiers. To this purpose the Aichi Target 9 established "By 2020, invasive alien species and pathways are identified and prioritized, priority species are controlled or eradicated, and measures are in place to manage pathways to prevent their introduction and establishment" [78].

This target addressed the following implementation measures:


The Invasive Species Specialist Group also developed a Toolkit for the economic analysis of Invasive species [107] which addresses the causes and the impacts of IAS, the related costs and benefits, the valuation of ecosystem impacts and the actions to address IAS.

Besides the information, the international and national legislations, the definition of biosecurity programs is also important, identifying IAS that pose a high risk of causing damage, and establishing measures to protect natural resources and citizens. Currently, biosafety on plant IAS is governed internationally by the International Plant Protection Convention, which establishes harmonised guidelines and standards between countries to limit the spread of IAS while promoting free trade [25].

Addressing IAS control in islands is less difficult than in continental land masses since it may be possible to prevent the entry of these IAS at the border in the management plan. Yet, it is a complex operation. The engagement of the community

*Conserving Endemic Plant Species in Oceanic Island's Protected Areas DOI: http://dx.doi.org/10.5772/intechopen.100571*

(citizen science) is of utmost importance, to allow early identification of new invasions. Engaging volunteers in surveillance and monitoring is also a low-cost, large-scale, and a long-term option, for those countries that are not able to implement integrated IAS surveillance programs [25].

Established populations of IAS have traditionally been managed by mechanical or physical control, chemical control, and biological control, all with successes and failures, but with increasing efficiency [108]. New management and innovative eradication technologies have been implemented in recent years, based on molecular genetics, notably the use of gene-silencing for the control of invasive populations that affect plants [109], or gene-editing technology, together with transgenes, which is a whole new technological approach that can help in the control and management of IAS [110].

#### **4.5 Conservation and restauration**

As defined by article 8 of the CBD, *in-situ* conservation is "the conservation of ecosystems and natural habitats and the maintenance and recovery of viable populations of species in their natural surroundings […]" [74]. This definition includes the conservation of natural and semi-natural ecosystems in various types of PAs, aiming to conserve the ecosystem biodiversity, the landscape, to provide habitat for targeted organisms, such as endemic species. It also involves the conservation of targeted species in their natural habitat or ecosystem through conservation or management plans, the definition of recovery programmes for threatened, rare or endangered wild species and the restoration, and the recovery, or rehabilitation of habitats [111].

The *in-situ* conservation action is often complemented with *ex-situ* conservation actions, such as the cultivation in botanical gardens, the maintenance of seeds in seedbanks, arboreta collections, clone banks, cryopreservation, seed production, or other activities, while removed from many of their natural ecological processes, and being managed by humans [112]. The *ex-situ* conservation has enabled research into the causes of the primary threats, such as habitat loss, IAS, and exploitation, while also enabling conservation training and education activities. Different *ex-situ* activities allow the restauration of threatened wild populations, which can be used for population restauration (reinforcement or reintroduction) or conservation introduction, improve the demographic or genetic viability of wild plant populations by reducing the impact of anthropogenic or stochastic threats on these populations [112].

The use of *in-situ* and *ex-situ* conservation action has been an integrated approach increasingly used in the management of islands PAs, namely, to conserve endemic species [105, 111, 113–116]. The Hawai'i islands alone, e.g., have 14 state, federal, non-profitable and international institutions involved in *ex-situ* and *in-situ* conservation programmes, which are responsible for research in plant conservation, native ecosystems, managing wild plants, tissue culture, seed bank maintenance, species populations recovery, besides data management, defining strategy, priorities and planning, outreach, and training, among other activities [117]. A good example is the *ex-situ* conservation of the Hawaiian Vulcan palm (*Brighamia insignis*) which currently survives mainly in gardens.

*Inter-situ* conservation is a mixture of the *in-situ* and *ex-situ* conservation practices, creating a new community or ecosystem that is partly managed and partly wild. This conservation strategy is used when a threatened species had to be removed from its original range due to threats, and, thus, is conserved in a new location where those threats could be mitigated or are absent [118]. A step forward in conservation measures is "conservation-oriented restoration"

[119], which aims to conserve biodiversity in partially degraded habitats, either for assisted establishment or assisted colonisation. The concept aims to create partially new ecosystems with species compositions that differ from their historical analogues. This restoration aims to conserve endangered species and their habitats, rather than to improve the well-being of local communities by improving ecological services. The concept makes ecological restoration an integral part of conservation planning and implementation and uses threatened plant species in habitat restoration. Another interesting approach within the restauration measures are the Nature based Solutions (NbS), defined as "actions to protect, manage, and restore natural or modified ecosystems, that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefits" [120]. This rather new concept aims to work with the ecosystems and the native species within these ecosystems, using them to adapt and mitigate climate change. NbS are categorised into five main approaches [121]:


Accordingly, many NbS being implemented in PAs fall within the species and ecosystems conservation measures, as well as within the management tools that must be adopted when PAs are involved. In small oceanic islands, NbS can provide significant human wellbeing and biodiversity benefits, linking ecological, climate, and human wellbeing issues in an integrated, ocean-focused, and climate-responsive manner [122, 123].

### **5. Conclusions**

The conservation of endemic plants in protected areas of oceanic islands is a vast, complex, and challenging topic, which has received the attention of many researchers in the past. These plants grow in small population due to low habitat availability, and isolated evolution. Therefore, the islands' ecosystems and their endemic plants are very vulnerable to current threats, such as climate change and the introduction of invasive alien species, but also to pollution, habitat fragmentation, fire, and other anthropogenic threats.

The conservation measures implemented so far are not consensual and many have not been successful, although important steps have been taken. The study and definition of major biodiversity hotspots, the establishment of thousands of protected areas, the creation of databases with information on relevant habitats and species, and the implementation of many *in-situ* and *ex-situ* conservation projects, with their pros and cons, are some of the cornerstones of conservation knowledge and management.

New scientific approaches are appearing in conservation, namely the Nature Based Solutions, the conservation-oriented restoration, the gene-editing

*Conserving Endemic Plant Species in Oceanic Island's Protected Areas DOI: http://dx.doi.org/10.5772/intechopen.100571*

technology together with transgenes, which are already showing promising results in plant conservation.

Despite the scientific efforts, the importance of efficient management of protected areas and of the political priority given to conservation should be stressed. Without them, all scientific achievements are irrelevant.
