Perception of Neighboring Plants by Rhizomes and Roots: Morphological Manifestations of a Clonal Plant

A previous study showed that clonal morphology of the rhizonlatous grass Elyttr~rs 1rtrceolntrr.s ssp. Inrrceolctrrs (Scibncr & J.G. Smith Gould) was influenced more by ncighbouring root systcms than by the local distribution of nutrients. In this study we determine whether individual rhizomcs or roots of E. lntrcrolnt~rs perccivc ncighbouring root systems and how this is manifested in morphological responses of E. Inr~ceolnt~rs cloncs. El~~trr~a lat~ccolat~rs was grown in the same bin with Psc.lrdoroe~trerin spicnta (Pursh) A. Love or Agropyrotr rlesertor~rrt~ (Fisch. ex Link) Schult. plants. E1~~tr11r.s I~~~~ceolat~rs was separated from its neighbours by different barriers. The b:~rricrs allowed either only E. latzceolnt~rs roots; only a single E. Intrceolntus primary rhizome: or both roots and rhizomes to contact the neighbour root system. When only a single E. Irrticeolrrt~rs primary rhizome with potentially developing branching rhizomes made contact with the ncighbour, the clonal structure of E. Irrticeolntu.~ was modificd more with P. spicatn as the neighbour than with A. desertor.rrttl. With root contact of E. Irrt~ceolrrt~r.s alone there was a similar effect with the neighbouring plants, but there was a Inore marked inhibitory effect on E. Irrt~c~eolrrt~r.s clonal growth with P. s/~iccrtn than with A. desertor~rtrr, compared with the treatment with only a single rhizome in contact with the neighbour. Root resource compctition in the unconstrained treatment (roots and rhizomes) between neighbouring plant and E. Irrtzceolatrrs was more apparent with A. rlesertor~rn~ than with P. sl~iccrtcr. This study is one of the first to documcnt that rhizome and root contact of a clonal plant with its neighbours may induce different clonal responses depending on the species of neighbour

Biological soil crusts exhibit a dynamic response to seasonal rain and release from grazing with implications for soil stability

In Northern Mexico, long-term grazing has substantially degraded semiarid landscapes. In semiarid systems, ecological and hydrological processes are strongly coupled by patchy plant distribution and biological soil crust (BSC) cover in plant-free interspaces. In this study, we asked: 1) how responsive are BSC cover/composition to a drying/wetting cycle and two-year grazing removal, and 2) what are the implications for soil erosion? We characterized BSC morphotypes and their influence on soil stability under grazed/non-grazed conditions during a dry and wet season. Light- and dark-colored cyanobacteria were dominant at the plant tussock and community level. Cover changes in these two groups differed after a rainy season and in response to grazing removal. Lichens with continuous thalli were more vulnerable to grazing than those with semi-continuous/discontinuous thalli after the dry season. Microsites around tussocks facilitated BSC colonization compared to interspaces. Lichen and cyanobacteria morphotypes differentially enhanced resistance to soil erosion; consequently, surface soil stability depends on the spatial distribution of BSC morphotypes, suggesting soil stability may be as dynamic as changes in the type of BSC cover. Longer-term spatially detailed studies are necessary to elicit spatiotemporal dynamics of BSC communities and their functional role in biotically and abiotically variable environments

Stewardship of future drylands and climate change in the global South : challenges and opportunities for the Agenda 2030

For the purpose of achieving sustainable development in the context of a changing climate, the development and implementation of tripartite cooperation tools, into a transatlantic cooperation framework, is the crux of a project to bring about a transdisciplinary platform focused on research, technology, and innovation in drylands. It finds its roots in the Agadir Declaration of May 2016. The objective of the platform is to set up a 'hub or rear base' at the University of Ibn Zohr in Agadir to develop transdisciplinary research and training mechanisms on climate change and its impacts on the functioning of ecosystems and their goods and ser-vices in arid and semiarid regions. Currently, the main challenge to achieve sus-tainable development resides in ensuring that decision-making processes are supported by science. How to translate scientific knowledge on complex long-term issues at the national, cross-regional, and transatlantic scale into better informed public policy remains an open question for multi-sectoral partnerships. The main thread underlying this chapter relates to the establishment of interface models between science and policy: what challenges will the Agadir Platform assume to bridge various forms of interdisciplinary science and policy expertise to inform decision- makers on long-term wicked problems related to drylands socio-ecological systems

The Agadir platform : a transatlantic cooperation to achieve sustainable drylands

For the purpose of achieving sustainable development in the context of a changing climate, the development and implementation of tripartite cooperation tools, into a transatlantic cooperation framework, is the crux of a project to bring about a transdisciplinary platform focused on research, technology, and innovation in drylands. It finds its roots in the Agadir Declaration of May 2016. The objective of the platform is to set up a 'hub or rear base' at the University of Ibn Zohr in Agadir to develop transdisciplinary research and training mechanisms on climate change and its impacts on the functioning of ecosystems and their goods and ser-vices in arid and semiarid regions. Currently, the main challenge to achieve sus-tainable development resides in ensuring that decision-making processes are supported by science. How to translate scientific knowledge on complex long-term issues at the national, cross-regional, and transatlantic scale into better informed public policy remains an open question for multi-sectoral partnerships. The main thread underlying this chapter relates to the establishment of interface models between science and policy: what challenges will the Agadir Platform assume to bridge various forms of interdisciplinary science and policy expertise to inform decision- makers on long-term wicked problems related to drylands socio-ecological systems

Technical note: Application of geophysical tools for tree root studies in forest ecosystems in complex soils

While semiarid forests frequently colonize rocky substrates, knowledge is scarce on how roots garner resources in these extreme habitats. The Sierra San Miguelito Volcanic Complex in central Mexico exhibits shallow soils and impermeable rhyolitic-rock outcrops, which impede water movement and root placement beyond the soil matrix. However, rock fractures, exfoliated rocks and soil pockets potentially permit downward water percolation and root growth. With ground-penetrating radar (GPR) and electrical resistivity tomography (ERT), two geophysical methods advocated by Jayawickreme et al. (2014) to advance root ecology, we advanced in the method development studying root and water distribution in shallow rocky soils and rock fractures in a semiarid forest. We calibrated geophysical images with in situ root measurements, and then extrapolated root distribution over larger areas. Using GPR shielded antennas, we identified both fine and coarse pine and oak roots from 0.6 to 7.5 cm diameter at different depths into either soil or rock fractures. We also detected, trees anchoring their trunks using coarse roots underneath rock outcroppings. With ERT, we tracked monthly changes in humidity at the soil–bedrock interface, which clearly explained spatial root distribution of both tree species. Geophysical methods have enormous potential in elucidating root ecology. More interdisciplinary research could advance our understanding in belowground ecological niche functions and their role in forest ecohydrology and productivity