POP-CHANGE · Predicting and managing plant population responses in human altered ecosystems

Predicting and managing plant population responses in human altered ecosystems

POP-CHANGE (www.pop-change.com) We are living through a time of unprecedented change to the environmental drivers of species persistence, species interactions, ecosystem function and ecosystem service provision. Understanding the sustainability of future biodiversity and the life support systems that biodiversity provides will require a detailed understanding of the functioning of human influenced ecosystems, the effects of interventions to these systems and societal goals and constraints on intervention. POP-CHANGE leverages existing data-sets on plant population and community dynamics and spatial locations to gain insight on three objectives: 1. Comparative population ecology 2. Predicting plant population responses to nutrient addition 3. Cost effective interventions to achieve environmental or societal goals 1. Comparative population ecology POP-CHANGE has enabled participation in the international COMPADRE and COMADRE demography database projects where we have made two large databases of plant and animal demography fully accessible to the public (www.compadre-db.org) (Salguero-Gomez et al. 2015; Salguero-Gomez et al. 2016a). We have shown that 55% of the variation in plant life-history strategies is captured using two independent axes: the fast–slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other (Salguero-Gomez et al. 2016b). We found that both phylogeny and geography have predictive power for some population dynamic metrics but that this power diminishes quickly with both geographic distance (beyond approx. 35km) and phylogenetic divergence (10-100mya) (Coutts et al. 2016). The formation of the PLANTPOPNET network (www.plantpopnet.com) has enabled extensive sampling of the population dynamics of a widespread plant species which will enable the development of novel models of habitat suitability for population growth at the global scale. Funding from POP-CHANGE enabled a workshop held in March 2014 for the steering committee of PLANTPOPNET (www.plantpopnet.com) to finalise the protocol for data collection. The project has enjoyed considerable success and currently has data from >70 sites spread across 16 countries with >40 participating ecologists (www.plantpopnet.com). 2. Predicting plant population responses to nutrient addition A new NutNet site in an Irish grassland at Slieve Carran, Co. Clare, which forms part of the observational network of site data in NutNet (http://www.nutnet.umn.edu/). Three years of data have been collected (2015-2017) and the experimental nutrient addition and fencing treatments have been applied (2016-2018). The Slieve Carran NutNet site is the first of its kind in Ireland and one of 14 sites in Europe. Irish grasslands are relatively unusual as they are exposed to high precipitation and low rates of Nitrogen deposition which distinguishes them from other European grasslands in the network. Nitrogen deposition data have been collected during the 2015-2016 year. Participation in the NutNet project (http://www.nutnet.umn.edu/ ) has revealed impacts of nutrient addition on species diversity, whilst highlighting the importance of less studied nutrients, such as K and micronutrients, for grassland productivity, and point to significant variations in the type and degree of nutrient limitation. Nutrient addition consistently reduces local species diversity through light limitation but species loss due to eutrophication in grasslands can be ameliorated where herbivory increases ground level-light. Eutrophication can also serve to destabilise plant communities, not as expected, by species diversity loss, but by an increase in the temporal variation of productivity in combination with a decrease in species asynchrony in diverse communities (Hautier et al. 2014). We have shown that an integrative model of diversity-productivity relationships, taking into account a wider range of hypotheses about how these are related, has substantially higher explanatory power than traditional bivariate analyses (Grace et al. 2016). Nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light (Borer et al. 2014). Nutrient availability limited productivity at 31 of the 42 grassland sites. And pairwise combinations of N, P, and K+μ co-limited ANPP at 29 of the sites. Nitrogen limitation peaked in cool, high latitude sites. Our findings highlight the importance of less studied nutrients, such as K and micronutrients, for grassland productivity, and point to significant variations in the type and degree of nutrient limitation. We suggest that multiple-nutrient constraints must be considered when assessing the ecosystem-scale consequences of nutrient enrichment (Fay et al. 2015). Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands (Seabloom et al. 2015). A review article on the topic of how biogeographic origin affects ecology has been highly cited (Buckley & Catford 2016). 3. Cost effective interventions to achieve environmental or societal goals An economic sensitivity analysis was developed & multiple value systems were evaluated (Kerr et al. 2016). Management of invasive populations is typically investigated case-by-case. Comparative approaches have been applied to single aspects of management, such as demography, with cost or efficacy rarely incorporated. We calculated the ranks of management actions for 14 species in five countries that extends beyond the use of demography alone to include multiple metrics for ranking management actions, which integrate cost, efficacy and demography (cost-effectiveness) and managers’ expert opinion of ranks. A multidimensional view of the benefits and costs of management options provides a range of single and integrated metrics. These rankings, and the relationships between them, can be used to assess management actions for invasive plants. The integrated cost-effectiveness approach goes well ‘beyond demography’ and provides additional information for managers; however, cost-effectiveness needs to be augmented with information on off-target effects and social impacts of management in order to provide greater benefits for on-the-ground management.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз