Classical biological control for the protection of natural ecosystems

Abstract

Keywords: Invasive species Ecosystem function Insect pests Invasive plants Ecological restoration Biological control Natural ecosystems a b s t r a c tOf the 70 cases of classical biological control for the protection of nature found in our review, there were fewer projects against insect targets (21) than against invasive plants (49), in part, because many insect biological control projects were carried out against agricultural pests, while nearly all projects against plants targeted invasive plants in natural ecosystems. Of 21 insect projects, 81% (17) provided benefits to protection of biodiversity, while 48% (10) protected products harvested from natural systems, and 5% (1) preserved ecosystem services, with many projects contributing to more than one goal. In contrast, of the 49 projects against invasive plants, 98% (48) provided benefits to protection of biodiversity, while 47% (23) protected products, and 25% (12) preserved ecosystem services, again with many projects contributing to several goals. We classified projects into complete control (pest generally no longer important), partial control (control in some areas but not others), and ''in progress," for projects in development for which outcomes do not yet exist. For insects, of the 21 projects discussed, 62% (13) achieved complete control of the target pest, 19% (4) provided partial control, and 43% (9) are still in progress. By comparison, of the 49 invasive plant projects considered, 27% (13) achieved complete control, while 33% (16) provided partial control, and 49% (24) are still in progress. For both categories of pests, some projects' success ratings were scored twice when results varied by region. We found approximately twice as many projects directed against invasive plants than insects and that protection of biodiversity was the most frequent benefit of both insect and plant projects. Ecosystem service protection was provided in the fewest cases by either insect or plant biological control agents, but was more likely to be provided by projects directed against invasive plants, likely because of the strong effects plants exert on landscapes. Rates of complete success appeared to be higher for insect than plant targets (62% vs 27%), perhaps because most often herbivores gradually weaken, rather than outright kill, their hosts, which is not the case for natural enemies directed against pest insects. For both insect and plant biological control, nearly half of all projects reviewed were listed as currently in progress, suggesting that the use of biological control for the protection of wildlands is currently very active.

Susceptibilidad del Olmo (Ulmus pumila), y de cinco especies arbóreas nativas del centro-sur de la Provincia de Córdoba (Argentina), a la infección por Pleurotus ostreatus (Agaricales: Pleurotaceae).

“…Sin embargo, el daño producido por las especies invasoras no puede ser revertido tan fácilmente. Mientras la mejor legislación y las herramientas de detección son de vital importancia para la prevención de nuevas invasiones, los invasores -una vez establecidos -pueden persistir indefinidamente y dispersarse más allá de sus límites ecológicos (Van Driesche et al, 2010). Por tal motivo las invasiones biológicas han sido reconocidas como una de las causas principales del cambio ecológico y plantean graves riesgos para la estabilidad de los ecosistemas en todo el mundo (Harwood & Parajulee, 2010).…”

“…Existen vastos antecedentes de proyectos de control biológico que han contribuido con éxito a la protección de la flora y la fauna de muchos ecosistemas naturales, y son actualmente un componente en muchos planes de recuperación y de esfuerzos de restauración en todo el mundo (Van Driesche et al, 2010). Por lo que el control biológico clásico constituiría una poderosa herramienta que potencialmente puede resolver muchos problemas de plantas e insectos invasores en los ecosistemas naturales.…”

“…En este caso el implementar control biológico puede significar un riesgo demasiado grande. También puede suceder que varias especies invasoras que coexisten pueden requerir de control, como grupo de plantas invasoras similares, en estos casos, el control biológico de un solo invasor puede ser insuficiente para lograr la restauración ecológica de la comunidad debido a que la disminución de la especie blanco puede favorecer el crecimiento de otra especie invasoras residente (Van Driesche et al, 2010). Todos estos aspectos deben ser tenidos en cuenta a la hora de plantear las estrategias en los planes de gestión de las áreas (Ziller & Zalba, 2007).…”

Best practices for the use and exchange of invertebrate biological control genetic resources relevant for food and agriculture

“…IBCAs have played an important role in controlling pests of consequence in agriculture, forestry, human health and the environment (van Driesche et al 2010;Cock et al 2015;Heimpel and Mills 2017). In particular, introduction of IBCAs to combat invasive alien species has been and continues to be a primary focus.…”

Long-term conservation and rehabilitation of threatened rain forest patches under different human population pressures in West Africa

“…A high degree of biodiversity is the basis of organic farming (Pimentel et al 1997, Mäder et al 2002, IAASTD 2008, in particular crop protection, varietal development and climate change mitigation. Thus, alternate hosts, shelter and food for natural enemies of pests are important in biological control (Neuenschwander et al 2003, van Driesche et al 2010) and wild relatives of crop plants, such as yams, provide genetic resources for adapting crops to climate change (Corlett 2014). Nature reserves must therefore be considered a prudent investment even though knowledge and understanding of their interactions with agriculture are still sketchy and need further research (Wrangham and Ross 2008).…”