Nonlinear effects of group size on collective action and resource outcomes

Abstract

For decades, scholars have been trying to determine whether small or large groups are more likely to cooperate for collective action and successfully manage common-pool resources. Using data gathered from the Wolong Nature Reserve since 1995, we examined the effects of group size (i.e., number of households monitoring a single forest parcel) on both collective action (forest monitoring) and resource outcomes (changes in forest cover) while controlling for potential confounding factors. Our results demonstrate that group size has nonlinear effects on both collective action and resource outcomes, with intermediate group size contributing the most monitoring effort and leading to the biggest forest cover gain. We also show how opposing effects of group size directly and indirectly affect collective action and resource outcomes, leading to the overall nonlinear relationship. Our findings suggest why previous studies have observed differing and even contradictory group-size effects, and thus help guide further research and governance of the commons. The findings also suggest that it should be possible to improve collective action and resource outcomes by altering factors that lead to the nonlinear group-size effect, including punishing free riding, enhancing overall and within-group enforcement, improving social capital across groups and among group members, and allowing self-selection during the group formation process so members with good social relationships can form groups autonomously.casual inference | commons governance | ecosystem services | biodiversity conservation | sustainability

Performance and prospects of payments for ecosystem services programs: Evidence from China

“…A previous study by our research group has found that panda habitat (for which forest cover is essential), recovered faster in household monitored parcels than in government monitored parcels, after controlling for other contextual factors (e.g., elevation, slope, aspect, distance to the main road) (Tuanmu, 2012). We have also found that the effects of group size (i.e., the number of households for monitoring a forest parcel) on household monitoring efforts and forest outcomes are nonlinear, with intermediate group size (i.e., 9 in a range from 1 to 16 households) performing the best (Yang et al, 2013c). The optimum group size also shifts with context.…”

“…Moreover, the main activities responsible for deforestation in the reserve (i.e., logging and fuelwood collection) have been reduced due to the implementation of NFCP (see Section 3.2 below). Our previous studies (Tuanmu, 2012;Viña et al, 2011;Yang et al, 2013c) also suggest that the NFCP has been a major driving force of forest change in the reserve and surrounding areas since 2001. Viña et al (2011) indicated that NFCP together with GTGP led to the forest transition in Wenchuan County, from a net forest loss in 1990s to a net forest increase from to 2007.…”

“…Tuanmu (2012 suggested that controlling for other confounding factors different NFCP monitoring approaches and payment rates in different areas caused different change rates of panda habitat (of which forest is an essential component) across space. Yang et al (2013c) showed that different NFCP monitoring efforts of household groups led to varied changes in forest cover. Therefore, using the historical forest trend from 1965 to 2001 to estimate the forest area in 2007 as a without-PES baseline constitutes a reasonable approximation for evaluating the additionality of the NFCP implementation.…”

“…All local residents are encouraged to report illegal activities and will be rewarded in cash by the Bureau. If any illegal activity is detected in a forest parcel, all households in its corresponding group will have the same amount of payment deduction, unless they identify the culprits of the illegal activity to the Bureau (Yang et al, 2013c).…”

“…However, this approach turned out to be very difficult to implement because of the difficulty in clarifying forest parcel boundaries. Therefore, the Bureau finally decided to assign large forest parcels, defined using natural boundaries (e.g., rivers, ridges, valleys), to groups ranging in size from 1 to 16 households (Yang et al, 2013c). Of the 40,100 ha of forest assigned to household monitoring activities, around 16,700 ha were assigned to individual households while the remaining areas were assigned to groups with two or more households.…”