The Alpine Pals are an international group of part-time ecologists representing Canada, Chile, France, the Republic of Georgia, Mexico, Spain, Switzerland, the UK and the USA. We share an interest in (1) community ecology, (2) species interactions (3) finely crafted adult beverages, and (4) an unhealthy obsession with cushion plants. While poorly defined in terms of membership, number, and consistent participation, the Pals have have worked together in mountains systems all over the world including the Alps, the Caucasus, the Andes, the Rocky Mountains, the Brooks Range, the New Zealand Alps, and the Pyrenees. For roughly 15 years, we have studied competitive and facilitative interactions in alpine systems and and the implications of these interactions for community theory.
Lohen Cavieres and Ray Callaway
Currently we are analyzing a global dataset for which spatial associations have been measured between "foundation species ", those with a cushion morphology, and all other species in the community. These associations have been measured in over 12 mountains ranges, at over 80 sites, for over 60 species of cushion plants, and for approximately a total of 2,000 species in communities. Our preliminary results indicate that that cushions in alpine systems throughout the world have strong positive effects on whole community diversity. However, these facilitative effects are farstronger in some places than in others, and the strength of the effect at particular sites is inversely correlated with estimates of productivity. In other words, whole community facilitation is more important in low-productivity and high stress environments. We are also finding strong phylogenetic signals in our data - some phylogenetic lineages of cushions appear to be better facilitators than others.
Christian Schob & Zaza Kikvidze
We have also explored the ramifications for formal community theory in which interactions that have recently been prominent in plant ecology are explicitly considered , namely facilitation and indirect effects among competitors. These interactions do not support the traditional individualistic perspective. We believe that rejecting strict individualistic theory will allow ecologists to better explain variation occurring at different spatial scales, synthesize more general predictive theories of community dynamics, and develop models for community-level responses to global change. We introduced the concept of the integrated community (IC) which proposes that range from highly natural plant communities individualistic to highly interdependent dependingon synergism among: (i) stochastic processes, (ii) the abiotic tolerances of species, (iii) positive and negative interactions among plants, and (iv) indirect interactions within and between trophic levels. All of these processes are well accepted by plant ecologists, but no single theory had sought to integrate these different processes into our concept of communities.
Brad Cook & Brad Butterfield
Rob Brooker & Chris Lortie