The study was conducted along a section of River Bortoh in Nkambe Central Subdivision, Donga-Mantung Division, North-West Region, Cameroon, on 9 March 2026. Five sites were selected along the river corridor by purposive sampling to capture variation in accessibility, land use, and vegetation cover. The surveyed reach was 250 m long and was divided into five 50-m sites arranged sequentially from upstream to downstream (Sites 1 - 5). At each site, observations covered both riverbanks along the full 50-m longitudinal segment. The five site segments therefore represent the upstream-to-downstream order of the assessed reach; no separate gap between successive 50-m site segments was recorded. Site locations, including GPS coordinates and elevation, were recorded in the field for subsequent mapping and incorporation into the site-level database.

At each site, a structured field observation protocol, adapted from established rapid riparian and stream-corridor assessment frameworks, including the Riparian, Channel, and Environmental (RCE) inventory of [5] and the physical habitat characterization component of the USEPA Rapid Bioassessment Protocols ([1]), was used to record five categories of site-level data:

1) Accessibility indicators: access route type, distance to nearest road, terrain, and safety considerations, including human and wildlife presence.

2) Vegetation characteristics: dominant vegetation type, riparian width, dominant plant life forms, dominant species, and presence of species of invasive concern.

3) Disturbance and land-use indicators: evidence of farming, grazing intensity, logging/fuelwood extraction, fire signs, and waste dumping/pollution.

4) Hydrological and geomorphic characteristics: river flow status, bank condition, floodplain presence, and signs of recent flooding.

5) Suitability for detailed sampling: site representativeness, vegetation intactness, feasibility of establishing permanent monitoring plots, and overall recommendation for inclusion in the main baseline survey and restoration.

Data were collected through direct field observation at each site, supported by structured checklists to standardize recording across observers and minimize omission of key indicators. Both banks were surveyed at every site. Riparian width was measured as the horizontal distance from the edge of the water body outward to the point where the stream no longer interacts with or influences bank-side vegetation. The outer boundary was identified from the visible transition from stream-influenced vegetation and soil conditions toward upland vegetation and/or a clear topographic break.

Ordinal categories were assigned in the field based on direct observation against a standardized coding scheme: disturbance indicators (farming, grazing, logging/fuelwood extraction) were scored as None (0), Low (1), Moderate (2), or High (3); binary indicators (fire signs, waste/pollution, floodplain presence, recent flood signs) were recorded as Yes (1) or No (0); river flow status was scored as No flow (0), Low flow (1), Moderate flow (2), or High flow (3); and bank condition was recorded as Eroding (0) or Stable (1). For reproducibility, disturbance categories were operationalized using observable evidence within the assessed 50-m bank segment. None indicated no direct evidence; Low indicated isolated evidence affecting less than approximately 25% of the observed bank segment; Moderate indicated repeated evidence affecting approximately 25% - 50%; and High indicated widespread or near-continuous evidence affecting more than approximately 50%, or extensive direct conversion of the riparian area. For grazing, evidence included livestock presence, tracks, dung, browsing, and trampling; for farming, cultivated plots, planting, clearing, or crop rows; and for logging/fuelwood extraction, cut stems/stumps, removed woody vegetation, or stacked fuelwood. Binary fire and waste indicators were recorded as Yes when visible evidence was present and No when none was observed. Species of invasive concern were recorded only at the species or taxonomic level where field observations indicated conspicuous colonization and the taxon was considered locally problematic as an aggressive or introduced colonizer. Because this rapid assessment did not include a formal invasive-status verification, the term “species of invasive concern” is used cautiously. The original record of “fern” was not retained as an invasive record because it is a broad group rather than a species-level identification and the field assessment did not establish its invasive status. The outcome categories were defined as follows: representativeness was Fair when a site typified the disturbed corridor but provided limited structural variation, and Good when it captured comparatively greater structural or habitat variation; vegetation intactness was Low when vegetation was strongly simplified and dominated by shrub-grass cover with clear disturbance, and Moderate when some additional structural complexity was retained despite disturbance; plot feasibility was Moderate when permanent plot establishment was possible but required minor access, clearing, or marking adjustments, and High when a stable, accessible area allowed plot establishment with minimal constraints; and a site was Recommended when it was accessible, sufficiently representative, and feasible for repeated baseline monitoring. Site-level scores were tabulated and compared descriptively across the five sites; given the small number of sites, no inferential statistical testing was performed, and comparisons are reported as observed patterns rather than statistically validated differences.

All five sites were accessible via footpaths and, in most cases, roads, with distance to the nearest road ranging from 10 m (Site 4) to 300 m (Site 2) (Table 1). Terrain was undulating and broadly consistent across all sites. Human activity was recorded as a safety consideration at every site, and wildlife presence was additionally noted at Sites 1, 3, and 4.

Vegetation at all five sites was dominated by shrubland and grassland rather than closed-canopy riparian forest. Riparian width ranged from 20 m (Site 5) to 50 m (Sites 1, 2, and 4). Dominant plant life forms were shrubs, herbs, and grasses at four sites; Site 5 additionally supported a tree component. Dominant species varied by site: fern and elephant grass (Pennisetum purpureum) at Sites 1 and 2; raffia palm (Raphiafarinifera), acacia, and eucalyptus (Eucalyptus grandis) at Site 3; spreading rush (Juncus patens) and elephant grass (Pennisetum purpureum) at Site 4; and elephant grass and eucalyptus at Site 5. Species of invasive concern were recorded at four of the five sites: elephant grass at Sites 1 and 5, eucalyptus at Site 3, and Cyperussp. and eucalyptus at Site 4. Site 2 was the only site with no species of invasive concern detected. “Fern” is retained as a dominant vegetation observation but is not classified as invasive because it was recorded only as a broad group rather than a species-level taxon.

Farming was the dominant disturbance across the corridor, scored High at four sites (Sites 1, 2, 4, 5) and Moderate at Site 3. Grazing intensity was highest at Site 2 (High) and lowest at Sites 3 and 5 (Low). Logging or fuelwood extraction was minimal overall, recorded as None at Sites 1 - 3, Moderate at Site 4, and Low at Site 5. Evidence of fire use was present at four sites (Sites 1 - 4) and absent only at Site 5. Waste dumping or pollution was recorded at a single site (Site 5) (Figure 1).

Figure 1. Disturbance and land-use pressure across the five field assessment sites along River Bortoh. The plot includes only farming, grazing, and logging/fuelwood extraction, which use the 0 - 3 ordinal intensity scale; fire signs and waste/pollution were binary indicators and are therefore excluded from this figure.

River flow was Low at four sites and Moderate at Site 5 (Figure 2). Bank condition was Stable at all five sites, with no active erosion recorded. No floodplains and no signs of recent flooding were observed at any site. These observations describe physical conditions during the field visit and do not establish longer-term hydrological or geomorphic stability.

Figure 2. Hydrological and geomorphic conditions across the five field assessment sites along River Bortoh.

All five sites were judged appropriate for detailed ecological survey and monitoring. Sites 1 - 3 were rated Fair and Sites 4 - 5 Good in overall representativeness of the river ecosystem. Vegetation intactness was Low at four sites and Moderate at Site 4. Feasibility of establishing permanent monitoring plots was Moderate at four sites and High at Site 5. All five sites were recommended for inclusion in the main baseline survey.

The classification criteria applied to these outcomes were: Fair representativeness, typical disturbed corridor conditions with limited structural variation; good representativeness, comparatively greater structural or habitat variation; Low vegetation intactness, strongly simplified shrub-grass vegetation with clear disturbance; moderate vegetation intactness, some retained structural complexity despite disturbance; moderate plot feasibility, permanent plot establishment possible with minor logistical constraints; high plot feasibility, stable and accessible area permitting plot establishment with minimal constraints; recommended, site accessible, sufficiently representative, and feasible for repeated baseline monitoring.

Table 1. Site-level field assessment results across five sites along River Bortoh.

These findings should be interpreted with the limitations of a rapid field-assessment design in mind. First, disturbance and vegetation indicators were assigned using ordinal, observer-based scoring rather than quantitative measurement (e.g., percent cover, species counts, sediment or discharge measurement), which limits statistical comparison between sites and introduces a degree of subjectivity into category assignment. Second, the assessment was conducted at a single time point, and therefore cannot capture seasonal variation in flow, vegetation phenology, or disturbance intensity. Third, the five sites, while arranged to capture variation along the surveyed reach, are not a statistically representative or randomized sample of the full river system, and findings should not be extrapolated beyond the surveyed reach without further sampling. These limitations are inherent to the rapid-assessment design and mean the results should be treated as indicative rather than definitive.