Diverse microbial communities live in the gut regions of animals. The precise ecological and evolutionary circumstances that govern relationships between hosts and their gut communities is unclear. In this study, we hypothesize that host feeding strategy shapes the microbial communities within the gut systems of insects. We collected five insect species from the Sevilleta National Wildlife Refuge that exhibited herbivorous, detritovorous and carnivorous diets.
The management of the Pacific sardine is currently based on an environmental parameter, the surface temperature measured at the Scripps Pier. In the past sardine recruitment and Pier temperature were related. However, once current data on recruitment are included in the analysis no significant relationship between Pier temperature and recruitment are evident. We observed that Pier temperature and temperature in the primary sardine habitat have diverged over the last decades. Thus we explored relationships between temperature in the Southern California Bight and sardine recruitment.
The discovery of the tardigrade, Milnesium sp., in the McMurdo Dry Valleys, Antarctica, and the potential implication for biotic interactions
The McMurdo Dry Valleys, Antarctica, are a cold desert and represent one of the most inhospitable environments on earth. As a consequence the food webs are simple compared to most other terrestrial ecosystems, and limited to microbes and the nematode Scottnema lindsayae in dry areas, which includes most of the landscape. However, the few wet areas represent hotspots for soil organisms and support a greater diversity of soil fauna, often including the nematode genera Plectus and Eudorylaimus, and a few species of rotifers and tardigrades.
We are examining the growth, growth history and climate sensitivity of white and black spruce trees on the floodplains of the major rivers fed by glacial meltwater in Interior Alaska. To date we have sampled 624 trees on 41 sites distributed across 1,783 km of the Yukon River, 375 km of the Tanana River, and 370 km of the Kuskokwim River, for a total of 2,528 km of river length.
Increasing atmospheric CO2 will likely affect both the hydrologic cycle and ecosystem productivity. Current assumptions that increasing CO2 will lead to increased ecosystem productivity and plant water use efficiency (WUE) are driving optimistic predictions of higher crop yields as well as greater availability of freshwater resources due to a decrease in evapotranspiration.
The propagating response of inner shelf circulation to wind relaxations along the central California Coast
Following relaxations prevailing equatorward winds, warm water from the Santa Barbara Channel flows poleward around Point Conception and along the central California coast. Sequences of satellite sea surface temperature images show the events as bands of warm water extending up to 20 km offshore. Characteristics of these flows were examined using time series of currents and temperature from an array of moorings along the inner shelf (15 m depth), a mooring on the mid-shelf (100 m depth), and surface current observations from high frequency radars.
Oribatid mites are among the most diverse soil mesofauna, and they possess a variety of metabolic and morphological feeding adaptations. Unfortunately, our understanding of the mechanisms by which oribatids may influence decomposition dynamics is incomplete. A microcosm experiment was conducted in which corn and oak leaf litter were incubated in the presence and absence of actively feeding oribatid mites Scheloribates sp. Our objective was to quantify the effects of Scheloribates sp. on microbial activity and carbon cycling within litter.
Recent 15N tracing studies have highlighted the important role biotic assimilation plays in stream N retention, yet the fate of N following assimilation is not well understood. One potentially important fate is indirect denitrification, a process in which locally mineralized and nitrified N is denitrified before being exported to the water column. We conducted a series of in-situ chamber experiments in which patches of stream bottom were labeled with 15N to investigate the fate of assimilated N.
Spatial patterns of structures (e.g., nests and burrows) in animal populations can provide insight into underlying ecological processes. Banner-tailed kangaroo rats (Dipodomys spectabilis) and harvester ants (Pogonomyrmex rugosus) are the largest and most dominant granivores found in rodent and ant communities of the northern Chihuahuan Desert. Both species build conspicuous, above-ground structures and are highly territorial.