Lepidoptera larvae (caterpillar) abundance and biomass in the northern hardwood forests of central New Hampshire, USA, shows large interannual fluctuations in aggregated caterpillar biomass (21-fold variation in caterpillars/ 8000 leaves) that were spatially correlated across a regional landscape. Primary production of these mature forests has not varied over this period, and many hundreds of Lepidoptera species share comparatively few host plants.

The goal of this working group is to continue discussions initiated at the 2009 Science Council meeting that were focused on designing a continental-scale research program to assess how the major socio-ecological systems of the U.S.

Disturbance ecology is a central theme at all LTER sites, yet disturbance datasets are often not standardized such that synthetic analyses and comparisons across sites are challenging. The goal of this workgroup is to bring together scientists collecting and maintaining long-term datasets on disturbance in an effort to develop effective formats for standardized datasets that can be included in the EcoTrends project. A second goal will be to initiate these multi-site comparisons across different disturbance events in the form of a draft manuscript.

The goal of this workgroup is to continue discussions initiated at an EcoTrends working group meeting held in April 2009. The goal of the group is to develop synthetic products based on the long term ANPP and species richness datasets in the EcoTrends database as well as other sources of information. The ANPP and richness data and figures in EcoTrends consist of simple temporal trends over time. Theory predicts a hump-shaped relationship between species richness and ANPP over space, and a positive relationship between species richness and NPP within a site, up to some asymptotic value.

The notion that ecological systems can exist in two or more states has become a central idea at the interface of basic and applied ecology. Climate change, stochastic events, and natural resource-use pressures can lead ecological systems to cross thresholds and undergo transitions, regime shifts, phase shifts, or catastrophic shifts (i.e., threshold dynamics) that are problematic to predict, important to society, and are difficult or impossible to reverse.

The Detritus Inputs and Removal Treatments (DIRT) were established at the H.J. Andrews Experimental Forest to examine the effects of organic matter manipulations on soil organic matter (SOM) chemistry and nutrient cycling. In 2007, after ten years of manipulations, isotope dilution methods were used to estimate gross N mineralization and nitrification rates among the six treatments that control the rate and quality of SOM inputs (control, double wood, double litter, no roots, no litter, and no inputs).

Shrubs have displaced grasses throughout much of the world’s arid and semiarid lands (drylands) over the past century. In the Chihuahuan Desert in southern New Mexico, the conversion of black gramma grasslands to mesquite shrublands over the past 100 years has been well documented. The extent to which this displacement of grasses by shrubs has altered leaf litter quality and the spatial distribution of litter inputs and thus nutrient turn over via decomposition is unknown.

 Future changes in climate are likely to strongly affect plant physiological and growth parameters, and thus potentially influence competitive interactions among plants. We used rainout shelters and sprinklers to test the influence of changes in precipitation on aboveground physiological parameters and belowground growth of honey mesquite (Prosopis glandulosa) and black grama (Bouteloua eriopoda) at the Jornada Basin LTER. In this area of the northern Chihuahuan Desert, mesquite and other woody plants have encroached into former desert grasslands over the past 150 years.

Soil microbial communities play a pivotal role in providing ecosystem services, given that they are key drivers of biogeochemical processes such as carbon and nitrogen cycling. As species-rich communities, made-up of populations with short generation times, it is commonly assumed that there is a high degree of functional redundancy within soil communities with respect to broad-physiological processes, such as organic carbon decomposition.

Decomposition is a fundamental driver of biogeochemical cycling that dictates nutrient availability, carbon storage, and community composition. Although mechanistic models of decomposition dynamics have been successfully applied to many different systems, predicting decomposition in drylands has remained problematic due to a poor understanding of the driving variables. A recent study in the Sonoran Desert found a strong positive relationship between decomposition rates and the amount of soil deposited onto litter, which varied by a factor of six as a function of microsite vegetation cover.