Mapping adaptive capacity and smallholder agriculture: applying expert knowledge at the landscape scale

The impacts of climate change exacerbate the myriad challenges faced by smallholder farmers in the Tropics. In many of these same regions, there is a lack of current, consistent, and spatially-explicit data, which severely limits the ability to locate smallholder communities, map their adaptive capacity, and target adaptation measures to these communities. To explore the adaptive capacity of smallholder farmers in three data-poor countries in Central America, we leveraged expert input through in-depth mapping interviews to locate agricultural landscapes, identify smallholder farming systems within them, and characterize different components of farmer adaptive capacity. We also used this input to generate an index of adaptive capacity that allows for comparison across countries and farming systems. Here, we present an overview of the expert method used, followed by an examination of our results, including the intercountry variation in expert knowledge and the characterization of adaptive capacity for both subsistence and smallholder coffee farmers. While this approach does not replace the need to collect regular and consistent data on farming systems (e.g. agricultural census), our study demonstrates a rapid assessment approach for using expert input to fill key data gaps, enable trans-boundary comparisons, and to facilitate the identification of the most vulnerable smallholder communities for adaptation planning in data-poor environments that are typical of tropical regions. One potential benefit from incorporating this approach is that it facilitates the systematic consideration of field-based and regional experience into assessments of adaptive capacity, contributing to the relevance and utility of adaptation plans.     

Heading Households and Heading Businesses: Rural Kenyan Women in the Informal Sector

The dynamics of intra-household economics among sedentary farmers in rural Kenya suggest that women, whether or not they have a male household head, are responsible for providing basic resources to insure the daily survival of household members. Many rural Kenyan women operate small businesses in rural market centers in order to meet these obligations, and many of these women are also heads of their households. This paper examines women's resource bases for establishing and maintaining small-scale businesses. Compared to women who are associated with male-headed households, women who head households have fewer resources for establishing businesses which in turn generate lower earnings. At the same time, these women are almost completely dependent on their businesses for meeting the household's needs.     

Numerical Simulations of Large Earthquakes: Dynamic Rupture Propagation on Heterogeneous Faults

— Our current conceptions of earthquake rupture dynamics, especially for large earthquakes, require knowledge of the geometry of the faults involved in the rupture, the material properties of the rocks surrounding the faults, the initial state of stress on the faults, and a constitutive formulation that determines when the faults can slip. In numerical simulations each of these factors appears to play a significant role in rupture propagation, at the kilometer length scale. Observational evidence of the earth indicates that at least the first three of the elements, geometry, material, and stress, can vary over many scale dimensions. Future research on earthquake rupture dynamics needs to consider at which length scales these features are significant in affecting rupture propagation.     

Variation in the Sizes of Chthamalid ­Barnacle Post-Settlement Cyprids on European Shores

Abstract. As part of a wider study on the settlement and recruitment of Chthamalus spp. in Europe, this study investigated whether chthamalid cyprids can be separated by length on a European scale. Variation in cyprid length with latitude and temporal variation at selected localities were also examined. The lengths of cyprids collected between 1996 – 1999 on nine rocky shores in Europe are reported. Elminius modestus cyprids were found only at Roscoff, NW France and could be distinguished due to their carapace shape and length. They showed a unimodal length distribution, measuring between 450 and 625 µm, with no variation in length between the two sampling dates (1997 and 1998). Based on carapace shape and length, the remaining cyprids in the collections were identified as one of three chthamalid species, Chthamalus montagui, Chthamalus stellatus or Euraphia depressa. Bimodal length distributions of chthamalid cyprids were seen on some shores, while others had a single small‐sized modal group (representing C. montagui on Atlantic shores and/or E. depressa in the Mediterranean) separated from a few distinctly larger cyprids (C. stellatus). Metamorphs collected simultaneously with cyprid collections were identified as C. stellatus or C. montagui, except at Roscoff, where E. modestus were also found. In southern Portugal, where all metamorphs collected were C. montagui and adult C. montagui were the dominant barnacles, most cyprids measured between 350 and 550 µm long and this size distribution coincides with the distribution expected for C. montagui. Cyprids collected on these four more southerly Portuguese shores had the same modal length class (475 µm) and this remained constant between successive years at Luz and Albufeira, Algarve. The smallest (350 µm long) wild chthamalid cyprids found were from southern Portugal and Italy. In Spain, France and Ireland the smallest chthamalid cyprid was 425 µm long. The results from the present study support the hypothesis that on Atlantic shores cyprids of C. montagui can be separated from those of C. stellatus based on size, although there is some variation in cyprid length with latitude as well as temporal variation at selected localities.     

Evidence that biological activity affects Ocean Bottom Seismograph recordings

Brief and impulsive signals of uncertain origin appear regularly on records from Ocean Bottom Seismographs (OBS) of several institutions. These signals have been recorded on nearly all deployments of the Texas OBS, including sites at depths greater than 7000 m. At some sites, they account for over 90% of the events recorded. They are of short duration (usually 0.5–4.0 s) and have a characteristic frequency (usually in the range of 4–18 Hz) that differs from site to site. When networks of OBS instruments are deployed, the signals are not recorded simultaneously by different instruments. Neither the frequency content nor the distribution of durations of these signals is similar to what is observed for known earthquake events.We present evidence suggesting that the signals are of biological origin, perhaps caused by animals touching the OBS units. (1) The distribution of these signals on instruments deployed at depths shallower than 1000 m shows a 24 h periodicity, while there is a 24 h periodic pattern on instruments deployed at sites deeper than 1000 m (where there is no visible light). (2) The frequency of occurrence of signals is similar to the vertical distribution of biomass in the oceans, i.e., they appear most frequently on OBS instruments deployed at very shallow depths. (3) Biological material has been found attached to several OBS units upon recovery.University of Texas Institute for Geophysics contribution number 468.     

Predictability of South China Sea Summer Monsoon Onset

Predicting monsoon onset is crucial for agriculture and socioeconomic planning in countries where millions rely on the timely arrival of monsoon rains for their livelihoods. In this study we demonstrate useful skill in predicting year-to-year variations in South China Sea summer monsoon onset at up to a three-month lead time using the GloSea5 seasonal forecasting system. The main source of predictability comes from skillful prediction of Pacific sea surface temperatures associated with El NiÑo and La NiÑa. The South China Sea summer monsoon onset is a known indicator of the broadscale seasonal transition that represents the first stage of the onset of the Asian summer monsoon as a whole. Subsequent development of rainfall across East Asia is influenced by subseasonal variability and synoptic events that reduce predictability, but interannual variability in the broadscale monsoon onset for East Asian summer monsoon still provides potentially useful information for users about possible delays or early occurrence of the onset of rainfall over East Asia.