Search

Wildlife is one of the most important food resources in rural areas and popular among all social layers of Lao PDR. Numerous vertebrate species are sold at the local markets, but a comprehensive understanding of people’s involvement and their impact on survival of local populations remains insufficient. This study provides the first interdisciplinary assessment using a questionnaire-based survey approach to investigate both markets and households in Khammouane Province in central Lao PDR. Data were recorded during the dry season (October and November 2017), as well as the rainy season (June and July 2018). We documented 66 traded species, mainly intended for consumption purposes, with more than half of them protected under either national law or international convention/red list. Furthermore, an evaluation of wildlife use from urban to the most accessible rural areas, indicated differences in affordability and trapping behavior. Our results suggest that wildlife availabilities can less and less satisfy the unchanged demands.

According to the World Reference Base for Soil Resources (IUSS Working Group WRB, 2006), the differentiation of Acrisols and Alisols is based on the cation-exchange capacity of clay, which cannot be directly determined in the field, but needs expensive and time-consuming soil-chemical analyses. This is an unsatisfactory situation for pedologists, who urgently require a rapid field method to distinguish illuviation-type reference soil groups (Alisols, Acrisols, Luvisols, Lixisols). In this study, we tested the ability of gamma-ray spectrometry to separate major WRB reference soil groups in the field. The underlying hypothesis is that Alisols and Acrisols are distinguished by their clay mineral composition, which should be reflected by geochemistry and consequently gamma-ray radiation (i.e., K-containing illite vs. K-free kaolinite). Highly significant differences in their gamma-ray spectrum for K, Th, and U were found for limestone and its soils. Especially the K and Th signatures allowed a clear separation of Acrisols and Alisols. In general, the surface radiation was sufficient to separate these soils. Best results were revealed considering parent rock and the whole soil profile. This means by using a portable radiometer and a pH meter, all illuviation-type reference soil groups could be distinguished in this case. If applicable at other sites, this approach could enormously reduce expenditures for soil-chemical analysis needed to assist soil classification.

This study compares different soil mapping approaches in three different petrographic areas in order to test their suitability for regional mapping in northern Thailand. Sampling was based on transects or grid-based randomization. Maps were created based on expert knowledge (eye fitting) or using Classification Tree (CART algorithm) or the Maximum Likelihood approach. In addition, local knowledge-based-soil maps were created. Validation was performed using soil reference maps and independent sampling points. The mapping approaches based on transects and grid-based randomization showed a very high correspondence with the respective reference soil map and a very high degree of matching with independent sampling points. Both methods are best suited for sub-watershed scale. Mapping larger areas is difficult due to the inaccessibility of the mountainous regions. The soil maps based on Maximum Likelihood showed a high correlation with the respective reference soil maps and the individual sampling points. Maximum Likelihood maps and Classification Tree maps showed similar levels of accuracy. The Maximum Likelihood approach is applicable to upscaling procedures; therefore, a calibration area is required which represents the target area. Local knowledge-based-soil mapping is very cheap and fast, but is restricted to village areas where classification often varies even within a village. Despite this, local knowledge is very useful for soil reconnaissance surveys, as well as to acquire an overview of the major distribution of soils and their properties. Upscaling of local knowledge due to its inherent inconsistency is not realistic. Among the mapping approaches investigated only the Maximum Likelihood approach and the Classification Tree method are suitable for upscaling procedures. Both approaches require a calibration area which can only be mapped by transects or grid-based random sampling. These approaches are more efficient in the case of known ex-ante soil variability, so that the distance for transects, grid cell size, and amount of sampling points can be chosen in a proper way. It is useful to apply local knowledge in order to elevate ex-ante knowledge of soil information. In one pilot study local knowledge-based-soil sampling could reduce the amount of sampling points within a calibration area to less than the half used for transects and randomized mapping. The Maximum Likelihood approach applied afterwards provided an accuracy of at least 70% and hence is as accurate as the Classification Tree method. It seems to be most useful to combine the different approaches.

The information available in relation to soils in Southeast Asia’s (SEA) mountainous regions is still limited, and so our research tried to rectify this situation in two key ways. The first approach was to gather soil information in order to help develop a soil database for parts of mountainous SEA. This approach also included two further issues important to soil knowledge in SEA, as reported in this study: Savanna regions with underlying limestone are unique to SEA, resulting in specific soil landscapes with soils of various degrees of weathering. Non-sustainable agriculture affects soil fertility in the uplands of SEA, in particular the frequent problem of soil erosion at hill slopes adversely affects both soil physical and chemical properties. The second approach was to develop and progress methods so as to improve soil research and soil analysis. These approaches included (1) gamma ray spectrometry to retrieve airborne and ground-based data on natural radioactive isotopes of potassium, thorium and uranium in soils, as proxies for rock and soil formation, (2) an inter-comparison of state of the art soil mapping approaches in an development oriented context, and (3) the evaluation of ethnic soil knowledge systems, those considered useful in the identification of local soil distribution patterns, though not suitable for transfer to a larger scale.

The evolution of troglobites comprises three distinct problems: cave colonization by an epigean ancestor, the evolution of troglomorphies, and intra-cave speciation. The study of cave-dwelling planthoppers has contributed much to our understanding of troglobite evolution and provides useful model systems to test various aspects of the theoretic framework developed in recent years. Most promising in this respect are taxa with several closely related but independently evolved troglobiontic lineages, such as on the Canary Islands, in Queensland/Australia and on the Hawaiian Archipelago. Closely related species often occur in caves with comparable ecological parameters yet differ in their age. Here we use comparative age estimates for Australian and Hawaiian cave cixiids to assess the dynamics of reductive evolutionary trends (evolution of troglomorphy) in these taxa and cave planthoppers in general. We show that the degree of troglomorphy is not correlated with the age of cave lineages. Morphological alteration may not be used to draw conclusions about the phylogenetic age of cave organisms, and hypotheses based on such assumptions should be tested in light of these findings.