Statewide strategy for restoring Arizona's forests: Sustainable forests, communities, and economies

In 2003 Governor Janet Napolitano created the Forest Health Advisory Council and the Forest Health Oversight Council in response to the escalating number, frequency, and intensity of unnatural wildfires threatening Arizonas forests and communities (Executive Order 2003-16). The Councils were directed to develop scientific information and policy recommendations to advise the Governors administration in matters of forest health, unnaturally severe fire and community protection. In addition, the membership was designed to be inclusive to maximize the opportunity for collaboration and defuse the controversy surrounding forest management. (caution: 14 MB file!

Overwintering of gelatinous zooplankton in the coastal Arctic Ocean.

Jellyfish and ctenophore blooms are of increasing concern for human enterprise in marine waters, although bloom development remains poorly understood. A key factor in popula- tion dynamics of blooms is individual lifespan, which for most gelatinous zooplankton is assumed to be only a few months, often from spring to autumn. Accumulating evidence, however, indicates that some species may overwinter. In this study, we used video photography to quantify medusae and ctenophores beneath land-fast sea ice in the Chukchi Sea near Utqiag ̇ vik (Barrow), Alaska, USA, from May to June, 2011−2014. Our data show large Chrysaora melanaster medusae over- wintering near the bottom, which could contribute to multiyear population increases suggested for this species. C. melanaster medusae were observed dragging their tentacles along the bottom, possibly feeding on epibenthic macrofauna. This highlights an underappreciated mechanism for benthic−pelagic coupling by gelatinous zooplankton. Additionally, numerous individuals of 3 ctenophore and 1 hydrozoan species were seen primarily at the sea−ice interface rather than near the bottom. We hypothesize that overwintering of medusae and ctenophores under sea ice is favored by the continued availability of prey, related to high productivity in the coastal Arctic, including production by ice algae. Successful overwintering may also relate to physical sheltering and low water temperatures. Overwintering may be a common life-history trait for gelatinous zoo- plankton, with important implications for understanding annual and interannual population trends in many environments and has important implications for models including jellyfish and ctenophore populations and ecosystem dynamics

Seaweeds and their communities in polar regions

Polar seaweeds typically begin to grow in late winter-spring, around the time of sea-ice break up. They can grow under very low light enabling distributions to depths of ≥40 m. Moreover, they are physiologically adapted to low temperatures. Intertidal species exhibit a remarkable stress tolerance against freezing, desiccation and salinity changes. Endemism is much greater in the Antarctic compared to the Arctic species. On rocky shores of the Antarctic Peninsula and of Spitsbergen >80% of the bottom can be covered by seaweeds with standing biomass levels ≥20 kg wet wt m-2. Species richness and biomass declines, however, towards higher latitudes. Seaweeds are the dominant organisms in coastal waters and thus play important roles in benthic food webs and are likely to be of particular importance to benthic detrital food chains. Chemical defenses against herbivores are common in Antarctic, but not in Arctic seaweeds. More research is needed especially to study the effects of global climate changes

Canopy-Forming Seaweeds in Urchin-Dominated Systems in Eastern Canada: Structuring Forces or Simple Prey for Keystone Grazers?

Models of benthic community dynamics for the extensively studied, shallow rocky ecosystems in eastern Canada emphasize kelp-urchin interactions. These models may bias the perception of factors and processes that structure communities, for they largely overlook the possible contribution of other seaweeds to ecosystem resilience. We examined the persistence of the annual, acidic (H2SO4), brown seaweed Desmarestia viridis in urchin barrens at two sites in Newfoundland (Canada) throughout an entire growth season (February to October). We also compared changes in epifaunal assemblages in D. viridis and other conspicuous canopy-forming seaweeds, the non-acidic conspecific Desmarestia aculeata and kelp Agarum clathratum. We show that D. viridis can form large canopies within the 2-to-8 m depth range that represent a transient community state termed ‘‘Desmarestia bed’’. The annual resurgence of Desmarestia beds and continuous occurrence of D. aculeata and A. clathratum, create biological structure for major recruitment pulses in invertebrate and fish assemblages (e.g. from quasi-absent gastropods to .150 000 recruits kg21 D. viridis). Many of these pulses phase with temperature driven mass release of acid to the environment and die-off in D. viridis. We demonstrate experimentally that the chemical makeup of D. viridis and A. clathratum helps retard urchin grazing compared to D. aculeata and the highly consumed kelp Alaria esculenta. In light of our findings and related studies, we propose fundamental changes to the study of community shifts in shallow, rocky ecosystems in eastern Canada. In particular, we advocate the need to regard certain canopy-forming seaweeds as structuring forces interfering with top-down processes, rather than simple prey for keystone grazers. We also propose a novel, empirical model of ecological interactions for D. viridis. Overall, our study underscores the importance of studying organisms together with cross-scale environmental variability to better understand the factors and processes that shape marine communities

Deterrent activities in the crude lipophilic fractions of Antarctic benthic organisms: chemical defences against keystone predators

Generalist predation constitutes a driving force for the evolution of chemical defences. In the Antarctic benthos, asteroids and omnivore amphipods are keystone opportunistic predators. Sessile organisms are therefore expected to develop defensive mechanisms mainly against such consumers. However, the different habits characterizing each predator may promote variable responses in prey. Feeding-deterrence experiments were performed with the circumpolar asteroid macropredator Odontaster validus to evaluate the presence of defences within the apolar lipophilic fraction of Antarctic invertebrates and macroalgae. A total of 51% of the extracts were repellent, yielding a proportion of 17 defended species out of the 31 assessed. These results are compared with a previous study in which the same fractions were offered to the abundant circum-Antarctic amphipod Cheirimedon femoratus. Overall, less deterrence was reported towards asteroids (51%) than against amphipods (80.8%), principally in sponge and algal extracts. Generalist amphipods, which establish casual host–prey sedentary associations with biosubstrata (preferentially sponges and macroalgae), may exert more localized predation pressure than sea stars on certain sessile prey, which would partly explain these results. The nutritional quality of prey may interact with feeding deterrents, whose production is presumed to be metabolically expensive. Although optimal defence theory posits that chemical defences are managed and distributed as to guarantee protection at the lowest cost, we found that only a few organisms localized feeding deterrents towards most exposed and/or valuable body regions. Lipophilic defensive metabolites are broadly produced in Antarctic communities to deter opportunistic predators, although several species combine different defensive traits

Successional processes in Antarctic benthic algae

Despite the importance of benthic algal communities to Antarctic coastal ecosystems, much information about their dynamics is still needed. Primary succession processes in the Antarctic benthos are frequently initiated by ice-mediated disturbance and by the creation of denuded substrate following glacier retreat, both expected to increase in the future. Primary succession of benthic algae starts with rapid colonization by diatoms, ephemeral green algal filaments and propagules of annual and pseudoperennial macroalgae. Early stages of macroalgae can be particularly vulnerable to environmental stress factors, being critical for the structure of mature communities. The Antarctic environment is severely affected by global change, and successional patterns can change due to species-specific susceptibilities to abiotic and biotic drivers, introducing changes in the matter and energy flow in the coastal food webs.This chapter summarizes new advances in our knowledge on the successional dynamics of benthic primary producers in the Antarctic hard-bottom benthos. Manipulative experiments on the effects of grazing and ultraviolet (UV) radiation as drivers of the succession at early stages and long-term experiments carried out at sites with different environmental conditions are compiled. The gathered information can contribute to achieve a deeper knowledge of these key communities and their structure and functioning in a changing environment.Fil: Campana, Gabriela Laura. Universidad Nacional de Luján; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zacher, Katharina. Alfred Wegener Institute; AlemaniaFil: Momo, Fernando Roberto. Universidad Nacional de General Sarmiento; Argentina. Universidad Nacional de Luján; ArgentinaFil: Deregibus, Dolores. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Debandi, Juan Ignacio. Universidad Nacional de Luján; ArgentinaFil: Ferreyra, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Ferrairo, Marta E.. Universidad Nacional de La Plata; ArgentinaFil: Quartino, Maria Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin