From food to pest: Conversion factors determine switches between ecosystem services and disservices

Ecosystem research focuses on goods and services, thereby ascribing beneficial values to the ecosystems. Depending on the context, however, outputs from ecosystems can be both positive and negative. We examined how provisioning services of wild animals and plants can switch between being services and disservices. We studied agricultural communities in Laos to illustrate when and why these switches take place. Government restrictions on land use combined with economic and cultural changes have created perceptions of rodents and plants as problem species in some communities. In other communities that are maintaining shifting cultivation practices, the very same taxa were perceived as beneficial. We propose conversion factors that in a given context can determine where an individual taxon is located along a spectrum from ecosystem service to disservice, when, and for whom. We argue that the omission of disservices in ecosystem service accounts may lead governments to direct investments at inappropriate targets

Constraints to Rice Production Systems in Laos

In 1999, total rice production in Laos was more than 2.1 million tonnes, enough to make the nation self-sufficient in rice. Over the past 2 decades, total production has increased by about 100%, with most of the increase occurring in the rainfed lowlands where production jumped from 705 000 t in 1980 to 1 502 000 t in 1999. Even though the dry-season irrigated environment has increased production by almost nine times in the past decade (from 41 000 t in 1990 to 354 000 tin 1999) and further small-scale irrigation schemes are planned to achieve a total dry-season irrigated area of about 180 000 ha by 2005, the wet-season lowland environment will remain the most important rice-producing environment for the foreseeable future. Higher yields and reduced year-to-year variability in production can be expected with further intensification of production systems in the lowlands. However, further improvements in production will depend on higher levels of inputs and continued alleviation of some production constraints. The uplands will become less important for rice production as alternative, more sustainable technologies are developed to replace the current ‘slash-and-burn’ and shifting cultivation practices. This paper summarizes the known main abiotic and biotic production constraints in each of Laos’s rice-producing environments: wet-season lowlands, dry-season irrigated, and rainfed uplands, but not those socioeconomic constraints that can also have significant impact on farmer attitudes and production. The major production constraints in the main rice-producing environment—the wet-season lowland ecosystem of the Mekong River Valley—are drought and poor soil fertility. However, more than 10% of the wetseason lowlands in the central and southern agricultural regions are also regularly affected by flooding of the Mekong River. In these areas, flood damage is often regarded as a greater production constraint than drought. In the dry-season irrigated environment, poor soil fertility is the main abiotic constraint. Insect pests are becoming increasingly important in both these production systems. In existing production systems in the rainfed uplands, the main constraints are, in decreasing order of significance, weeds, rodents and drought. Farmers’ perceptions of the relative importance of production constraints in the uplands are generally more accurate than those in the lowlands. Poor soil fertility is often not rated among the most important constraints in the wet-season lowlands and dry-season irrigated environments, despite experimental evidence that often the greatest yield increases can come from improved plant nutrition. Until recently, farmers’ perceptions of the importance of insect pests in the lowlands often exaggerated their economic significance