Behavioral Responses to Knowledge and Resource Provision on Mangrove Restoration: Evidence from Mangrove Community Member in Indonesia

Intervention Design
The study conducted a cluster-randomized controlled trial to examine the implementation of alternative intervention modalities commonly used in community-based mangrove restoration programs. The intervention design was structured to reflect real-world policy instruments deployed in environmental and rural development contexts, particularly those emphasizing information dissemination, capacity building, and material support. Randomization was conducted at the mangrove community group level to minimize spillover effects and to align with the collective organization of restoration activities.
Three experimental arms were defined: a control group (C), a first treatment group emphasizing information and training (T1), and a second treatment group emphasizing information and material support (T2). All interventions were delivered following a standardized protocol and implemented during group-based sessions.

Control Group (C)
Participants in the control group received a single printed brochure. The brochure contained general information on mangrove ecology, including the role of mangroves in coastal protection, their contribution to ecosystem services, and basic descriptions of mangrove functions in coastal landscapes. The brochure was designed to mirror informational materials commonly distributed through public awareness campaigns or extension activities. No audiovisual materials, in-person training, or material inputs were provided to this group.

Treatment Group 1 (T1): Information and Training
Participants in Treatment Group 1 received an informational component and capacity-building intervention. In addition to the printed brochure provided to the control group, T1 participants viewed a 15-minute educational video. The video was developed based on Indonesia’s official mangrove restoration framework and produced in collaboration with the Peatland and Mangrove Restoration Agency. It featured local community members and practitioners demonstrating mangrove planting techniques, nursery-based seedling preparation, site selection considerations, and descriptions of mangrove ecosystem services.
Following the video screening, participants attended a 40-minute in-person short training session. The training focused on silvicultural practices tailored to mangrove ecosystems and was delivered by trained facilitators using standardized instructional materials. The session emphasized practical aspects of mangrove restoration, including planting methods, early-stage maintenance, and site-specific considerations relevant to coastal environments. No material input, such as seedlings or financial incentives, was provided to participants in this group.

Treatment Group 2 (T2): Information and Material Support
Participants assigned to Treatment Group 2 received a combination of intervention components. Like T1, T2 participants were provided with the printed brochure and viewed the same 15-minute educational video. However, participants in T2 did not receive the in-person training session. Instead, this group received material support in the form of mangrove seedlings.
Each participant in T2 received 30 free mangrove seedlings. The seedlings consisted of two species, Rhizophora mucronata and Rhizophora apiculata, which are widely used in mangrove rehabilitation programs in Indonesia. Species selection was based on their ecological suitability for coastal restoration, adaptability to local site conditions, and common use in nursery-based propagation systems. Seedlings were distributed directly to participants during the intervention session, with standardized quantities for each participant.

Standardization and Delivery
All intervention components were delivered in group settings according to a predefined schedule. Brochures were distributed at the outset of intervention activities across all study arms. Video screenings were conducted using identical audiovisual materials for both treatment groups. The short training session was implemented exclusively for T1 groups, while seedling distribution was implemented exclusively for T2 groups. No group received both the in-person training and the seedling provision.
This intervention structure generated three distinct exposure conditions: basic information only (C), information combined with training (T1), and information combined with material support (T2). The design reflects intervention bundles commonly used in environmental governance and community-based development programs and allows for a clear comparison of informational, capacity-building, and material inputs.

This study implements a randomized controlled trial with three experimental arms to document the delivery of alternative program inputs related to community-based mangrove rehabilitation. The intervention is designed to reflect commonly used approaches in mangrove rehabilitation programs, while maintaining strict separation between study arms and standardized implementation procedures.
Following baseline data collection, eligible participants are randomly assigned at the individual level to one of three groups: a control group, Treatment Group 1 (information-based input), or Treatment Group 2 (material support). Randomization is conducted prior to any intervention delivery using a prespecified randomization procedure. Treatment assignment is fixed for the duration of the study, and no reassignment or cross-over between groups is permitted.
Participants in the control group do not receive any intervention input from the research team beyond participation in baseline and endline surveys. They do not receive training sessions or seedlings. They only received a single printed brochure. The research team does not restrict control group participants from accessing information, resources, or support related to mangrove rehabilitation through external programs, personal networks, or independent initiatives.
Participants assigned to Treatment Group 1 (T1) receive a short, standardized information-based intervention. A short movie of mangrove and in-hand training as a single session during the intervention period. The session is designed in advance using prepared materials to ensure consistency across locations and facilitators. The content focuses on general and procedural aspects of mangrove rehabilitation, including common planting practices, maintenance considerations, and typical community roles in rehabilitation activities. The delivery follows a fixed structure and does not include interactive exercises, individualized guidance, or follow-up sessions. No material inputs, such as seedlings or tools, are provided to participants in this group.
Participants assigned to Treatment Group 2 (T2) receive material support in the form of mangrove seedlings. Seedlings are distributed during the intervention period following locally standard practices regarding species selection, quantity per participant, and timing. At the point of distribution, participants are informed of basic handling procedures necessary to receive the seedlings. The research team provides structured field training sessions, and prepared training materials are delivered to this group.
The interventions for T1 and T2 are implemented separately to prevent contamination across treatment arms. Implementation schedules are coordinated to avoid overlapping between information delivery and seedling distribution activities. Facilitators and field staff are instructed to strictly adhere to the assigned intervention protocols and avoid providing additional information or support beyond what is specified for each treatment group.
No financial incentives, sanctions, monitoring requirements, or performance-based conditions are attached to participation in any study arm. The study does not impose obligations regarding planting, maintenance, or reporting of activities associated with the intervention inputs. The research team does not conduct enforcement or compliance checks related to intervention uptake.
All interventions are implemented within a defined intervention window. The research team documents the timing, location, and completion of each intervention activity to ensure fidelity to the assigned treatment status. Any deviations from the planned implementation procedures are documented as part of the study.
This hidden intervention description is intended to provide a complete and transparent account of what was implemented in each study arm, enabling replication, methodological review, and post-study assessment of the intervention design once the study has been completed and unblinded.

2024-07-01

2024-09-30

The primary outcome of interest is planting number, defined as the total number of mangrove seedlings planted by an individual during the study period. This outcome captures the magnitude of individual-level contribution to mangrove rehabilitation activities and reflects variation in the intensity of planting behaviour across participants. Planting number is measured as a continuous variable at the individual level and recorded at follow-up after the assigned intervention is implemented.

Planting number is prioritised as the primary endpoint because it directly reflects the scale of rehabilitation activity undertaken by participants and allows for differentiation not only between those who engage in planting and those who do not, but also among participants who plant at different levels of intensity. By focusing on the number of seedlings planted, this outcome captures heterogeneity in effort and contributions that is not observable from binary indicators alone.

The primary outcome, planting number, is measured as the total number of mangrove seedlings planted by an individual during the study period. This variable is collected through structured follow-up survey questions asking respondents to report the number of seedlings they planted after the intervention. The outcome is recorded as a continuous, non-negative integer variable at the individual level and is not top-coded or otherwise transformed at the construction stage.

Secondary outcomes include knowledge level and planting decision. Knowledge level is measured as an individual-level score summarizing respondents’ understanding of mangrove rehabilitation practices, including general principles of planting, maintenance, and related concepts. This outcome captures changes in informational or cognitive dimensions associated with the intervention inputs. The planting decision is measured as a binary indicator reflecting whether an individual reports having engaged in mangrove planting during the study period (yes/no). This outcome captures the extensive margin of participation in planting activities.

The secondary outcome knowledge level is constructed as a composite index based on responses to multiple survey questions assessing individual knowledge related to mangrove rehabilitation. These questions cover key aspects of mangrove planting and maintenance practices, including general understanding of planting techniques, post-planting care, and related concepts. Each knowledge item is coded following a pre-specified scoring rule, and individual item scores are aggregated into a single index. The index is constructed consistently across all respondents, with higher values indicating higher levels of knowledge.

The secondary outcome planting decision is measured as a binary indicator capturing whether an individual reports having planted any mangrove seedlings during the study period. This variable is coded as one if the respondent reports planting at least one seedling and zero otherwise. The planting decision outcome captures the extensive margin of participation in mangrove planting activities and is derived directly from the same survey module used to elicit planting behavior

This study uses cRCT conducted in selected coastal communities. Eligible participants are randomly assigned, after baseline data collection, to one of three study arms: a control group and two treatment groups.
The control group receives no additional input from the research team beyond participation in study surveys, except for a single brochure. The treatment groups receive alternative inputs related to mangrove rehabilitation, consisting of either an information-based input or material support.
All interventions are delivered within a defined study period. No crossover between study arms is permitted. Outcome data are collected through follow-up surveys after the intervention period.

This study implements a cluster-randomized controlled trial to document the effects of alternative program inputs for community-based mangrove rehabilitation. The unit of randomization is the individual participant. Eligible participants are identified from selected coastal communities based on predefined inclusion criteria and enrolled prior to random assignment.
Baseline data are collected from all enrolled participants before randomization. Following baseline data collection, participants are randomly assigned to one of three study arms: a control group, Treatment Group 1, or Treatment Group 2. Random assignments are conducted using a pre-specified randomization procedure and are independent of participant characteristics, prior involvement in mangrove-related activities, or baseline responses.
Participants assigned to the control group receive no intervention from the research team, except a brochure. Participants assigned to T1 receive an information-based intervention on mangrove rehabilitation, combined with in-hand training. Participants assigned to T2 receive information-based intervention plus material support related to mangrove rehabilitation. Each participant is assigned to only one study arm, and treatment status remains fixed throughout the study.
Intervention delivery occurs within a defined intervention window following random assignment. The study design does not permit crossover between treatment arms. Implementation procedures are structured to minimize contamination across groups, including separate scheduling of intervention activities and clear instructions to field staff regarding adherence to assigned treatment protocols.
Outcome data are collected through follow-up surveys administered after completion of the intervention period. The timing of outcome measurement is defined in advance and applied uniformly across study arms. The study does not attach financial incentives, sanctions, or performance-based conditions to treatment assignment or outcome measurement.
The research team documents any deviations from the planned randomization or implementation procedures. This hidden experimental design description is intended to provide a complete and transparent account of the study design for replication, methodological review, and post-study evaluation once the trial has been concluded.

Randomisation was conducted by the research team using a computer-based random assignment procedure. The randomisation process was implemented in the research office after baseline data collection.
Participants were assigned individually to one of the study arms. To account for the structure of mangrove community groups, randomisation was conducted within pre-defined community group strata, while treatment assignment occurred at the individual level. All eligible individuals within each group had an equal probability of assignment to each study arm.

The unit of randomization is the individual participant (N = 863). Participants belong to 36 mangrove-community groups, which are used as strata for randomization. Treatment assignment occurs at the individual level within groups.

Yes

36 mangrove-community groups (clusters), within which individuals are randomly assigned to treatment.

863 individual participants across 36 mangrove-community groups.

Control group: 12 groups of mangrove community with 342 individuals. T1 group: 12 groups of mangrove community with 265 individuals. T2 group: 12 groups of mangrove community with 256 individuals

Power calculations are based on individual-level assignment (N = 863) with outcomes measured at the individual level and clustering at the mangrove-community group level (36 groups; average cluster size ≈ 24). MDEs are reported for two-sided tests with α = 0.05 and 80% power, assuming approximately equal allocation across three arms (≈ 288 per arm). Baseline standard deviations (SDs) are taken from pre-treatment measures (pooled across individuals): Knowledge (SD ≈ 1.14), Planting decision (SD ≈ 0.404), and Number of seedlings planted (SD ≈ 50.57). Using conservative intra-cluster correlation (ICC) values to account for clustering: ICC = 0.05 (MDE ≈ 34% of baseline SD): • Knowledge (score points): MDE ≈ 0.39 points (34% of SD) • Planting decision (proportion): MDE ≈ 0.138 (13.8 percentage points; 34% of SD) • Number of seedlings planted (seedlings): MDE ≈ 17.3 seedlings (34% of SD) ICC = 0.10 (MDE ≈ 42% of baseline SD): • Knowledge (score points): MDE ≈ 0.48 points (42% of SD) • Planting decision (proportion): MDE ≈ 0.171 (17.1 percentage points; 42% of SD) • Number of seedlings planted (seedlings): MDE ≈ 21.4 seedlings (42% of SD) The unit of analysis is the individual participant for all outcomes; clustering is at the mangrove-community group level.