Macroscale analysis of mistletoe host ranges in the Andean-Patagonian forest

The number of host species infected by a mistletoe (host range) is critical in that it influences prevalence, virulence and overall distribution of the parasite; however, macroecological analyses of this life history feature are lacking for many regions. The Andean-Patagonian forest, found along the southern Andes from 35 °S to Tierra del Fuego at 55 °S, contains 12 mistletoe species in three families (Loranthaceae, Misodendraceae and Santalaceae). By tabulating herbarium records, the host ranges and geographical distributions of these mistletoes were explored. Our results show that these parasites occur on 43 plant species in 24 families but with varying degrees of specificity. All Misodendrum species and Desmaria mutabilis (Loranthaceae) are specialists that use Nothofagus as their primary hosts. Tristerix and Notanthera (Loranthaceae) and Antidaphne and Lepidoceras (Santalaceae) are generalists parasitizing more than six host species from several genera and families. Although many of the mistletoe species are sympatric, there is low overlap in host use. Our data show that in the southern South American bioregion, generalist mistletoes have smaller geographic ranges than specialists. This contrast with a previous hypothesis that predicted mistletoes with large geographic ranges would also have large host ranges, and conversely, less diverse regions would have more specialised mistletoes.Fil: Amico, Guillermo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Nickrent, Daniel. Southern Illinois University; Estados UnidosFil: Vidal Russell, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Functional responses can unify invasion ecology.

We contend that invasion ecology requires a universal, measurable trait of species and their interactions with resources that predicts key elements of invasibility and ecological impact; here, we advocate that functional responses can help achieve this across taxonomic and trophic groups, among habitats and contexts, and can hence help unify disparate research interests in invasion ecology

Managing widespread, Alien plant species to ensure biodiversity conservation: A case study using an 11-step planning process

AbstractOne of the greatest threats to biodiversity is the invasion of ecological communities by alien plants. Management strategies for alien plants, however, rarely focus on specific biodiversity-conservation outcomes, and recovery actions rarely address the threat on a landscape scale. There are many reasons for these failures, including (1) limited knowledge of the native species at risk, (2) a disconnect between policy and management, (3) a disconnect between the fields of weed science and biodiversity conservation, (4) a dearth of data from management actions (for both threat abatement and recovery), and (5) the broadly held assumption that control of alien plants will by itself lead to a positive biodiversity response is often incorrect. Thus, alien plant management strategies with a conservation aim need to include planning processes and assessment measures to ensure that the aim is achieved. Here, I outline an example of the planning steps needed to ensure that the management of widespread alien plant species achieves the greatest possible conservation outcome, using the alien plant program for bitou bush (Chrysanthemoides monilifena) as a case study. In addition, I present an overview of the challenges faced and solutions developed during the transition from planning to management, along with some initial data to demonstrate the success and value of this investment in both planning and implementation during the past decade. Interim results from a series of sites have highlighted the success of the program and led to the program being acknowledged as an important ecological restoration project in Australasia. This success is highly dependent on extensive stakeholder involvement (across land tenures), dedicated coordination, and leadership. The planning process is now being adopted for other alien plants in Australia and can be modified to abate the threat from other alien organisms or other threats to biodiversity because the principles of each step are fundamentally similar.</jats:p

Encompassing the relative non-target risks from agents and their alien plant targets in biological control assessments

Criticisms about the safety of biological control of alien plants has resulted in a risk-averse approach, where the risks posed by the agent are paramount and the risks posed by the alien plant are neglected. We argue that the risk associated with nontarget damage from agents needs to be assessed relative to that of their target alien plants. A literature review of the non-target risks associated with biological control agents was undertaken in terms of the risk to native species from agents relative to the risk to native species from their alien plant targets. We then developed a framework that compares the consequence with the likelihood of non-target damage for both agents and their targets to provide an overall risk rating. Assessments of the risk of damage from both agents and their target alien plants will enable researchers, managers and policy makers to better assess the risks from biological control