Testing the use of interviews as a tool for monitoring trends in the harvesting of wild species

Abstract

Summary1. Many aspects of human behaviour impact on ecological systems. Ecologists therefore need information on changes in these behaviours and are increasingly using methods more familiar to social scientists. 2. Understanding patterns of wildlife harvesting is important for assessing the sustainability of harvests. Interviews are commonly used in which informants are asked to summarize their activities over a period of time. However, few studies have investigated the reliability of such data, the usefulness of interviews for monitoring trends, and how their information content can be maximized. 3. We carried out rapid assessment interviews with villagers in Madagascar about the quantity, timing and spatial patterns of crayfish Astacoides granulimanus and firewood collection. We compared the results with information from daily interviews with the same informants. We used mixed models to investigate how accurately people reported their activities in the rapid assessment interviews, and estimated the probability of detecting a change in harvesting from two such interviews using a Bayesian approach. 4. The interviews provided reliable information on quantities, effort, and the spatial pattern of harvesting. Simulations suggested the interviews would detect changes in catches and harvesting effort with reasonable power; for example, a 20% change in the amount of time spent crayfish harvesting could be detected with 90% power. Power is higher when the same informants are questioned in repeat interviews. 5. Synthesis and applications . Ecologists are increasingly using social techniques and it is vital that they are subject to rigorous testing to ensure robustness in trend detection. This study suggests that interviews can be used to monitor changes in harvesting patterns by resource users, but whether the power is adequate will depend on the needs of the study. To maximize the power of interviews, informants should be interviewed independently and the same informants interviewed in subsequent years.

Rainforest metropolis casts 1,000-km defaunation shadow

“…Compared with professional techniques, harvester catch per unit effort has been shown to be much cheaper and more efficient and result in similar levels of accuracy (43)(44)(45)(46). One increasingly popular use of harvester interviews is the collection of catch and effort data, to undertake analyses of catch, effort, and CPUE.…”

Caracterización de la comunidad de mamíferos de un área remota del sur de Chile mediante el uso combinado de metodologías

“…En ese sentido, los participantes de nuestro estudio mencionaron frecuentemente dos especies carismáticas de la zona como el puma y el monito de monte, pese a que no suelen alcanzar grandes densidades en bosques templados húmedos del sur de Chile (Iriarte 2008). Del mismo modo, las especies con importancia socioeconómica o cultural también suelen ser identificadas más fácilmente (Jones et al 2008, Karst & Turner 2011. En Huinay, únicamente el puma y la güiña pueden tener cierta importancia socioeconómica ya que pueden causar daños sobre el ganado o las aves de corral (e.g.…”

Changes in wild ungulate populations in Aragon, Spain between 2001 and 2010

“…In our study, the information gathered was based on two identical, questionnaire-based surveys done with the same procedures (expert inquiry). This fast, inexpensive approach provides facilitates the collection of highquality standardized data (Jones et al 2008). Table 1.…”

“…Table 1. The number (and %) of 10 x 10-km grid blocks in which wild ungulate species occurred in Aragon, Spain, in the 2001-2005(Osuna et al 2006-2008 Today in Aragon, sympatry among wild ungulate species is common, however, in the mid-19th C., they occupied marginal, fragmented habitats in the mountains (Gortázar et al 2000). Wild boar has been present throughout Aragon since at least the end of the 20th Century (Gortázar et al 2000), and the range has remained stable.…”