drag to orbit · scroll to zoom · tap any label or species for its story drag to orbit · pinch to zoom · tap a label
Forest loss 2001
2001 Hansen/UMD/Google/USGS/NASA GFC 2024 v1.12 2024
Viewpoint
1.8°N · 16.9°E
Sangha & Likouala · Republic of the Congo
Key
Map key
Densities are published per survey stratum, with no locations . Elephant, gorilla, chimpanzee and the duiker guild are shown on the strata they were counted in; the elephant is shown on three. Every other animal is listed for the landscape as a whole. None of these marks is a sighting; they are indicative of where a line was counted.
the landscape
Priority speciestap a species ↗
The index carries three lines, two of them guilds : the forest elephant on its own, the great apes combined, and the forest ungulates combined. These nine are the guild members and the candidates that were weighed; tap one to see which.
Altitude bands · 292–661 m across the strata
540+
460–540
400–460
360–400
330–360
292–330
Altitude. 369 m of range across 426 km, measured from the elevation model clipped to the nine strata. Half the landscape lies within 70 m of its lowest ground, and the surface is the top of the canopy. The landscape is structured by water, and no open dataset maps that boundary.
Live · forest condition
Deforestation — 30d
✕
The strata · the record
Ndoki-Likouala landscape
Nine management units in the northern Republic of the Congo, surveyed together on one line-transect protocol since 2006.
Landscape 34,000 km² stated, approx.
Strata, measured 35,111 km² the nine drawn
Outlines 8,144 km as digitised
Gazetted units 2 of 9
Strata drawn 9 18 rings
Elevation 292–661 m measured
Two of the nine are protected areas — Nouabalé-Ndoki National Park (4,071 km²) and the Lac Télé Community Reserve (4,219 km²). Four are logging concessions, three are swamp and other strata.Sangha Trinational — the national park is the Congolese leg of a UNESCO World Heritage property inscribed in 2012 with Dzanga-Ndoki (Central African Republic) and Lobéké (Cameroon), under an agreement among the three governments.Monitored across the line since 2006 — elephant, gorilla and chimpanzee counted inside the national park and in the surrounding concessions simultaneously, in partnership with the Ministry of Forest Economy. Few landscapes anywhere can support that comparison.The only one of seven that did not rise. The index shows a slight decline overall, with no statistically significant trend in the protected area. Inside the park, a negative point estimate with no significant trend indicates no detected change rather than a measured decline.
What this landscape shows
The disaggregation. Because the same protocol ran inside the park and in less protected units, the index can be split by protection status. The confidence intervals overlap, so no consistent difference could be established ; the point estimate for the less protected forest is negative.
Three lines. The index has three lines, two of them guilds rather than species: the forest elephant on its own, the two great apes combined, and the forest ungulates combined. The sensitivity analysis found that indexes with few species are sensitive to the removal of any one of them, and recommends at least ten. This is the smallest index in the set.
Why the guilds exist. In dense forest the track and sign of the forest ungulate species cannot reliably be told apart, and neither can the sign of gorilla and chimpanzee, so each group is counted as one guild.
Areas and outlines. The nine strata are drawn from WCS Congo's own survey-strata file (2024-12-10), cleared for public display; each unit's area is that file's own figure and the nine sum to 34,966 km². The landscape figure of 34,000 km² comes from the landscape description; it carries no date, method or gazetting authority and is approximate. Perimeter and compactness are computed from the drawn rings and are scale-dependent. Elevation 292–661 m is measured from Copernicus DEM GLO-30 clipped to the nine strata (5,752,842 cells); it is a canopy surface, not a ground survey. OpenStreetMap relation 12416802 corroborates the national park's outline independently (bounding boxes agree to about 600 m) and is deliberately not drawn on top of it. These polygons are survey strata, not protected-area boundaries: seven of the nine have no protected status.
✕
Connectivity · the record
How the strata and the parks connect
How the nine survey strata sit against each other and against the protected areas across the border, measured on the survey-strata file supplied by the authors and, for the neighbouring parks, on OpenStreetMap outlines. A shared boundary is an administrative fact and is not evidence that animals cross it. No corridor is drawn.
Park boundary 329 km Nouabalé-Ndoki, measured
Shared with concessions 141 km 43% of it
Along the CAR border ≈20 km within 250 m of Dzanga-Ndoki
Strata 9 of 9 one contiguous mosaic
The nine strata
Stratum Name in the file Designation (read from the name) km² in the file km² measured UFA Mokabi UFA Mokabi logging concession (UFA) 2,870 2,870.0 Nouabalé-Ndoki National Park PNNN national park 4,071 4,070.9 UFA Loundoungou UFA Loundoungou logging concession (UFA) 5,455 5,453.2 UFA Kabo UFA Kabo logging concession (UFA) 2,773 2,773.4 UFA Pokola UFA Pokola logging concession (UFA) 4,797 4,797.8 Loundoungou Marécage Loundoungou Marecage swamp-forest stratum 3,028 3,026.3 Bailly Marécage Bailly Marecage swamp-forest stratum 5,477 5,474.2 Lac Télé Community Reserve RC Lac Tele community reserve 4,219 counted as less protected 4,216.1 Batanga Batanga survey stratum 2,276 2,273.6 Nine strata 34,966 34,955.5
NdokiLikouala_SurveyStrata, WCS Congo's survey-strata file dated 2024-12-10, supplied with the paper's manuscript. Its attribute table holds only an id, an area in hectares and km², a name and a link id; the designations above are read from the names , not stated in the file. Batanga carries no stated designation and is drawn neutral. An earlier account of the same landscape gives its management units as NNNP 4,190, Kabo 2,870, Pokola 4,510, Loundoungou 4,230, Toukoulaka 2,080, Mokabi 2,670, Bailly/Bodingo swamps 3,770 and Lac Télé 4,380 km², as of 2006, with logging beginning in 1968 at Kabo and Pokola, 2000 at Mokabi and 2005 at Loundoungou [Stokes et al. 2010].
Where the strata meet
Unit Unit km within 250 m from A from B Nearest, km UFA Mokabi Nouabalé-Ndoki National Park 61.5 61.5 0.00 UFA Mokabi UFA Loundoungou 15.8 16.3 0.00 UFA Mokabi Réserve Spéciale de Dzanga-Sangha 0.0 1.3 0.04 Nouabalé-Ndoki National Park UFA Loundoungou 64.0 64.4 0.00 Nouabalé-Ndoki National Park UFA Kabo 15.3 16.5 0.01 Nouabalé-Ndoki National Park Parc national de Dzanga-Ndoki 20.1 0.0 0.11 Nouabalé-Ndoki National Park Réserve Spéciale de Dzanga-Sangha 15.0 20.4 0.19 UFA Loundoungou UFA Kabo 50.7 50.5 0.00 UFA Loundoungou UFA Pokola 145.2 145.3 0.00 UFA Loundoungou Loundoungou Marécage 1431.2 1440.0 0.00 UFA Loundoungou Bailly Marécage 713.2 705.3 0.00 UFA Loundoungou Lac Télé Community Reserve 4.5 4.5 0.00 UFA Kabo UFA Pokola 68.2 66.3 0.00 UFA Kabo Parc National de Lobéké 0.0 0.0 0.25 UFA Kabo Parc national de Dzanga-Ndoki 23.1 0.0 0.11 UFA Pokola Bailly Marécage 51.0 50.8 0.00 Loundoungou Marécage Lac Télé Community Reserve 20.7 20.9 0.00 Bailly Marécage Lac Télé Community Reserve 183.5 186.1 0.00 Lac Télé Community Reserve Batanga 88.5 88.4 0.00 Parc National de Lobéké Parc national de Dzanga-Ndoki 10.8 9.4 0.06 Parc national de Dzanga-Ndoki Réserve Spéciale de Dzanga-Sangha 33.0 33.0 0.00
Length of each outline lying within 250 m of the other, measured from both sides, with the minimum distance. Measured, tools/measure_strata_adjacency.py, 2026-09-30. Lobéké, Dzanga-Ndoki, Dzanga-Sangha and Ntokou-Pikounda are OpenStreetMap outlines, not the authors'; where one side reads 0.0 the two digitisations do not coincide within 250 m for long, and the figure is asymmetric for that reason. The park's 141 km with concessions: Loundoungou 64.0 km, Mokabi 61.5 km, Kabo 15.3 km.
Unit Protected area across the line or beyond Nearest, km UFA Mokabi Parc national de Dzanga-Ndoki 44.75 Nouabalé-Ndoki National Park Parc National de Lobéké 17.77 UFA Loundoungou Parc national de Dzanga-Ndoki 45.01 UFA Loundoungou Réserve Spéciale de Dzanga-Sangha 36.04 UFA Loundoungou Parc national de Ntokou-Pikounda 21.40 UFA Kabo Réserve Spéciale de Dzanga-Sangha 19.28 UFA Pokola Parc National de Lobéké 32.51 UFA Pokola Parc national de Dzanga-Ndoki 43.42 UFA Pokola Parc national de Ntokou-Pikounda 0.59 Bailly Marécage Parc national de Ntokou-Pikounda 22.14
Gaps under 50 km between a stratum and a neighbouring park it does not touch, measured. Lobéké (Cameroon) is 17.8 km from Nouabalé-Ndoki. UFA Pokola comes within 0.6 km of Ntokou-Pikounda. The Lac Télé Community Reserve is 60.7 km from the national park and reached through the Loundoungou concession and the Loundoungou swamp stratum, which it touches.
What the literature says about movement here
Elephants range widely and avoid roads. GPS-collared forest elephants in the Ndoki wilderness had home ranges of 211–2,402 km² (95% kernel), inside a roadless area of 11,793 km². Across six sites in three countries, only 1 of 27 collared elephants crossed an unprotected road outside a protected area, and it crossed at 14 times its normal speed. Ndoki collars ran October 1998 to November 2001. [Blake et al. 2008]The roadless area shrank. In the eight years after the collars went on, roads for extractive industry cut the Ndoki roadless area by more than 11,000 km², 88.9%. [Blake et al. 2008] Across the Congo Basin, the chance of finding elephants rose with distance from roads and was higher inside protected areas at every distance. [Blake et al. 2007]Three regimes side by side. The landscape was designed with integral protection in the park, community management in Lac Télé and wildlife management in the surrounding concessions; the monitoring programme covered about 28,000 km². Units with anti-poaching held gorillas, chimpanzees and elephants at consistently higher abundance than a neighbouring concession with no wildlife management, and logging roads were used by elephant poachers even where there were controls. Where protected from poaching, elephants and gorillas used the herbaceous growth of recently logged forest; chimpanzees preferred mature forest. [Stokes et al. 2010, 2006 survey]Unlogged forest as a source. In 1.2 million ha of concessions in northern Congo (749 transects, 3,450 km), mammal abundance was often related to distance from unlogged forest, and to distance from roads and villages. [Clark et al. 2009] In one concession surveyed before, during and after logging, chimpanzee nest encounter rates fell as human impact rose, while gorillas avoided active logging and roads but used recently logged areas rich in herbs. [Morgan et al. 2018]Logging brings hunters. Industrial logging raised the population of the logging towns by 69% (2000–2006) and bushmeat supply by 64%, and immigrants hunted 72% of all bushmeat. [Poulsen et al. 2009; the 69% as given by Stokes et al. 2010]The Sangha River. The river forming the international border inside the Sangha Trinational is a partial barrier to elephant movement between its parks; its crossing points were surveyed by dung count. [Weinbaum et al. 2007]Duikers move little. Radio-collared blue duikers under hunting in northern Congo had home ranges averaging 5.5 ha, annual survival of 0.94 and an immature dispersal rate of 0.25; two dispersing young moved about 1.5 km. Blue duiker is one of the six species in the index's ungulate line. [Mockrin 2010]Across three borders. The Sangha Trinational was established on 7 December 2000 by a cooperation agreement between Cameroon, the Central African Republic and the Republic of the Congo, followed by agreements on anti-poaching (28 June 2002) and free movement of its staff (4 February 2005). [Goué & Kana 2023] UNESCO describes its 1,787,950 ha buffer zone as a response to the ecological links between the property and its surroundings. [UNESCO, property 1380]Two transboundary landscapes. Ndoki-Likouala lies within two of the twelve priority landscapes of the COMIFAC Convergence Plan (2002): the Sangha Tri-National and Lac Télé–Lac Tumba. [SM Appendix A] On the Lac Télé side, the Lac Télé/Likouala-aux-Herbes and Grands Affluents Ramsar sites and Ngiri-Tumba-Maindombe in the DRC have been managed together as one transboundary Ramsar site since 2017, covering more than 129,000 km². [Ramsar Secretariat announcement, as reposted by the Congo Basin Forest Partnership; the month is not confirmed]Connectivity species. The forest elephant, bongo, leopard and red river hog are marked as both connectivity-important and cross-border on the candidate table. [SM Appendix B]
References
Blake S, Deem SL, Strindberg S, et al. (2008). Roadless wilderness area determines forest elephant movements in the Congo Basin. PLoS ONE 3(10): e3546. doi:10.1371/journal.pone.0003546
Blake S, Strindberg S, Boudjan P, et al. (2007). Forest elephant crisis in the Congo Basin. PLoS Biology 5(4): e111. doi:10.1371/journal.pbio.0050111
Stokes EJ, Strindberg S, Bakabana PC, et al. (2010). Monitoring great ape and elephant abundance at large spatial scales: measuring effectiveness of a conservation landscape. PLoS ONE 5(4): e10294. doi:10.1371/journal.pone.0010294
Clark CJ, Poulsen JR, Malonga R, Elkan PW (2009). Logging concessions can extend the conservation estate for Central African tropical forests. Conservation Biology 23(5): 1281–1293. doi:10.1111/j.1523-1739.2009.01243.x
Morgan D, Mundry R, Sanz C, et al. (2018). African apes coexisting with logging. Biological Conservation 218: 277–286. doi:10.1016/j.biocon.2017.10.026
Poulsen JR, Clark CJ, Mavah G, Elkan PW (2009). Bushmeat supply and consumption in a tropical logging concession in northern Congo. Conservation Biology 23(6): 1597–1608. doi:10.1111/j.1523-1739.2009.01251.x
Weinbaum KZ, Nzooh Z, Usongo L, Laituri M (2007). Preliminary survey of forest elephant crossings in Sangha Trinational Park, central Africa. Pachyderm 43: 52–62. doi:10.69649/pachyderm.v43i.127
Mockrin MH (2010). Duiker demography and dispersal under hunting in northern Congo. African Journal of Ecology 48(1): 239–247. doi:10.1111/j.1365-2028.2009.01107.x
Goué M, Kana CE (2023). The Sangha Trinational: an example of cross-border biodiversity management in Central Africa. In Managing Transnational UNESCO World Heritage Sites in Africa , 69–81. Springer. doi:10.1007/978-3-030-80910-2_7
UNESCO World Heritage List, property 1380, Sangha Trinational, open-data dataset whc001, read 2026-09-30.
Priority Species Index manuscript and Supplementary Material — the 2026-09-25 draft supplied to Landseed by the paper's authors (revision of 2026-09-29); unpublished and under review: SM Appendices A and B.
✕
Recovery and Translocations · the record
The survey, stratum by stratum
No translocation record No translocation, reintroduction, recolonisation or release record is available for Ndoki-Likouala. The one listed intervention for this landscape is a trade measure, not a release.
The record consists of the survey itself: the same line-transect protocol run inside the national park and in the less protected units since 2006, stratum by stratum.
Interventions and threats
1990: the ivory ban. "Ivory ban — Appendix 1 listing for the African elephant, making commercial trade illegal." This is the only listed intervention for the landscape. [SM Appendix F]What still presses. "Poaching, commercial hunting, logging and wildlife disease remain the most persistent threats." [SM Appendix A]Trend. Ndoki-Likouala is the one landscape of seven whose index "declined slightly overall", with "no statistically significant trend in the protected area". Split into the national park and the less protected units, "confidence intervals around the PSI overlapped, so no consistent difference could be established"; the less protected units' point estimate is negative. [manuscript, Results; Figure 3(b): density from line-transect distance sampling at multiple management units, with a 95% confidence interval]
Every stratum, every survey
Stratum km² 2006 2010 2016 2022 Forest Elephant dung per km² ± CV% Kabo 2,773 1050 ± 20.6 1018 ± 28.4 898 ± 14.3 1441 ± 22.3 NNNP 4,071 662 ± 15.8 680 ± 13.6 1013 ± 11.7 992 ± 16.45 Pokola 4,502 856 ± 27.2 683 ± 32 712 ± 29.6 110 ± 34.95 Sum (standardised) 2568 (1.0) 2381 (0.93) 2623 (1.10) 2543 (0.97) Ungulates dung per km² ± CV% Kabo 2,773 1218 ± 20 638 ± 27.4 594 ± 29.1 705 ± 17.05 LTCR 4,219 204 ± 32.8 194 ± 29 485 ± 27.7 340 ± 47.63 NNNP 4,071 1632 ± 12.7 927 ± 15.1 1676 ± 12.5 1005 ± 17.77 Pokola 4,502 1323 ± 23.1 765 ± 19.9 1838 ± 13.7 744 ± 20.19 Sum (standardised) 4377 (1.0) 2524 (0.58) 4593 (1.82) 2794 (0.61) Great Apes nests per km² ± CV% Kabo 2,773 264 ± 27.3 260 ± 41.1 274 ± 13.1 253 ± 26.97 LTCR 4,219 157 ± 22.1 257 ± 30.1 309 ± 32 121 ± 31.18 NNNP 4,071 152 ± 19.2 145 ± 17 198 ± 17.1 101 ± 21.04 Pokola 4,502 482 ± 26.6 661 ± 25.7 369 ± 17.7 214 ± 26.15 Sum (standardised) 1055 (1.0) 1323 (1.25) 1150 (0.87) 689 (0.60) Chimpanzee nests per km² Kabo 2,773 35 22 47 30 LTCR 4,219 17 27 25 3 NNNP 4,071 98 79 116 25 Pokola 4,502 37 49 33 25 Sum (standardised) 187 (1.0) 177 (0.95) 221 (1.25) 83 (0.38) Gorilla nests per km² Kabo 2,773 240 182 234 266 LTCR 4,219 145 229 260 127 NNNP 4,071 60 55 87 130 Pokola 4,502 454 655 317 240 Sum (standardised) 899 (1.0) 1121 (1.25) 898 (0.80) 763 (0.85)
SM Table 3, all five blocks as supplied: density estimates from line-transect distance surveys, dung per km² for elephant and ungulates, nests per km² for the great apes, with the coefficient of variation (%) where given. The value in brackets on each Sum row is the standardised value, as printed. Survey reports: Maisels et al. 2012, Brncic et al. 2018, Estienne et al. 2025, and Stokes et al. 2010. Priority Species Index manuscript and Supplementary Material — the 2026-09-25 draft supplied to Landseed by the paper's authors (revision of 2026-09-29); unpublished and under review.
How the index is computed here. The survey years align across the three lines, so the index is computed directly for each survey year rather than over standardised intervals; each line is set to 100 at its first survey and the lines are combined by geometric mean. [SM Appendix C; manuscript, Methods]
The protected / less protected split, as totals
Status Line Year Sum Strata summed Index Protected Elephant 2006 662 NNNP 100.0 Protected Great Ape 2006 152 NNNP 100.0 Protected Ungulate 2006 1632 NNNP 100.0 Unprotected Elephant 2006 1906 Kabo + Pokola 100.0 Unprotected Great Ape 2006 903 Kabo + Lac Télé + Pokola 100.0 Unprotected Ungulate 2006 2745 Kabo + Lac Télé + Pokola 100.0 Protected Elephant 2010 680 NNNP 102.7 Protected Great Ape 2010 145 NNNP 95.4 Protected Ungulate 2010 927 NNNP 56.8 Unprotected Elephant 2010 1701 Kabo + Pokola 89.2 Unprotected Great Ape 2010 1178 Kabo + Lac Télé + Pokola 130.5 Unprotected Ungulate 2010 1597 Kabo + Lac Télé + Pokola 58.2 Protected Elephant 2016 1013 NNNP 153.0 Protected Great Ape 2016 198 NNNP 130.3 Protected Ungulate 2016 1676 NNNP 102.7 Unprotected Elephant 2016 1610 Kabo + Pokola 84.5 Unprotected Great Ape 2016 952 Kabo + Lac Télé + Pokola 105.4 Unprotected Ungulate 2016 2917 Kabo + Lac Télé + Pokola 106.3 Protected Elephant 2022 992 NNNP 149.8 Protected Great Ape 2022 101 NNNP 66.4 Protected Ungulate 2022 1005 NNNP 61.6 Unprotected Elephant 2022 1551 Kabo + Pokola 81.4 Unprotected Great Ape 2022 588 Kabo + Lac Télé + Pokola 65.1 Unprotected Ungulate 2022 1789 Kabo + Lac Télé + Pokola 65.2
The authors' workbook (sheet "Congo"), all 24 status-level rows: three lines × two statuses × four years. Each "Number" was checked against SM Table 3: Protected is the national park's density alone; less protected is the plain sum of the other strata that were surveyed. So the Lac Télé Community Reserve, a protected area, is counted as less protected , and the elephant's less protected total has no Lac Télé term. Index = the total against 2006. The index lines with their confidence intervals are in the Priority Species Index chapter.
Year PSI (stated) SD 95% interval 2006 100.00 0.00 100.00–100.00 2010 87.97 7.98 73.24–104.61 2016 105.49 6.26 93.72–118.43 2022 74.75 6.39 63.01–87.92
The landscape index as the workbook states it: the mean of the Monte Carlo simulations, with its standard deviation and interval. Each species-year's uncertainty is propagated with 10,000 log-normal draws, recombined by geometric mean, and summarised by the 2.5th and 97.5th percentiles, following Soldaat et al. (2017). The authors note that this "does not explicitly account for other potential sources of uncertainty, such as sampling-design uncertainty, model-structure uncertainty, or serial or spatial autocorrelation". [SM Appendix C]
References
Priority Species Index manuscript and Supplementary Material — the 2026-09-25 draft supplied to Landseed by the paper's authors (revision of 2026-09-29); unpublished and under review: Appendices A, C and F; Table 3; Results; Figure 3(b); and the authors' workbook (sheet "Congo").
Maisels F, Nishihara T, Strindberg S, et al. (2012). Great ape and human impact monitoring training, surveys, and protection in the Ndoki-Likouala Landscape, Republic of Congo. WCS, 69 pp.
Brncic T, Madzoke B, Ndzai C, et al. (2018). Results of the 2016–2017 large mammal survey of the Ndoki-Likouala landscape. WCS Congo, 43 pp.
Estienne V, Strindberg S, Kuisma E, Abedine C, et al. (2025). Results of the 2022–2023 large mammal survey of the Ndoki-Likouala landscape. WCS Congo, Brazzaville, 83 pp.
Stokes EJ, Strindberg S, Bakabana PC, et al. (2010). PLoS ONE 5(4): e10294. doi:10.1371/journal.pone.0010294
Soldaat LL, Pannekoek J, Verweij RJT, van Turnhout CAM, van Strien AJ (2017). A Monte Carlo method to account for sampling error in multi-species indicators. Ecological Indicators .
✕
Global Conservation Value
Ndoki-Likouala, measured against the world
Ndoki-Likouala in a global context, each fact with its source, scope and date.
A World Heritage property across three countries. The Sangha Trinational was inscribed in 2012 under natural criteria (ix) and (x): 746,309 ha across three contiguous national parks (Lobéké in Cameroon, Dzanga-Ndoki in the Central African Republic and Nouabalé-Ndoki in the Republic of the Congo), with a buffer zone of 1,787,950 ha. UNESCO cites ecological processes on a very large scale in an intact landscape under (ix), and under (x) viable forest elephant populations and significant populations of western lowland gorilla and chimpanzee "both in and around the property". [UNESCO, property 1380]Wetlands of international importance. Lac Télé/Likouala-aux-Herbes (Ramsar site 950, 438,960 ha, designated 18 June 1998); Grands Affluents (site 1742, 5,908,074 ha, 13 December 2007); Sangha-Nouabalé-Ndoki (site 1858, 1,525,000 ha, 2009). Across the Sangha, Cameroon's site 1739 (6,200 ha, 2008) and the Central African Republic's site 1889 (275,000 ha, 2009). [Ramsar Sites Information Service, annotated lists]The world's largest tropical peatland lies to the south. The central Congo Basin peatland was mapped at about 145,500 km² holding about 30.6 Pg of carbon, the most extensive peatland complex in the tropics [Dargie et al. 2017]; a later field-based model puts it at 167,600 km² (36% of the world's tropical peatland area) storing 29.0 Pg C, about 28% of tropical peat carbon [Crezee et al. 2022]. These are two estimates of different method and date. Peat was sampled along the Likouala-aux-Herbes river in the Republic of the Congo.Intact forest. In 2000 the Republic of the Congo held 138,700 km² of intact forest landscape, 40.7% of its forest zone, and that area shrank by 17.7% between 2000 and 2013. Scope: the whole country. [Potapov et al. 2017]Among the highest elephant densities in the region. Forest elephants across Central Africa fell by about 62% between 2002 and 2011 and lost 30% of their range (range defined there by forest cover). The same study places northern Congo among the region's highest elephant densities and names Nouabalé-Ndoki, Dzanga-Sangha and the certified concessions that connect and surround them as nationally important sites. [Maisels et al. 2013]Three threatened flagship species. African forest elephant, Critically Endangered (2021 assessment); western lowland gorilla, Critically Endangered (2016, amended 2018); central chimpanzee, Endangered (2016). Categories only. [Red List assessments; categories via Wikidata, CC0]Formal standing. The 2002 COMIFAC Convergence Plan and the 2012 World Heritage inscription give this landscape formal standing; six of the seven landscapes in the index hold a formal standing under statute, treaty or a government-approved plan. Elephant, gorilla and chimpanzee monitoring has run since 2006 across park and concession simultaneously, in partnership with the Ministry of Forest Economy. [SM Appendices A and B]The only Afrotropical landscape in the index. The seven landscapes span five realms, and Ndoki-Likouala is the only one in the Afrotropics. [manuscript, Results]Monitored across the line since 2006. The same protocol has run in the national park and in the concessions simultaneously since 2006, in partnership with the Ministry of Forest Economy, "which few landscapes anywhere can match". [SM Appendices A and B] A protocol that excluded "great apes and forest elephants from Ndoki-Likouala" would be unacceptable to the agencies that would implement it. [manuscript, Discussion]Potential landscapes in the Republic of the Congo. The Republic of the Congo holds 7 “potential Priority Species Landscapes” larger than 1,000 km² (283,586 km² in total), 7 larger than 2,000 km² (283,586 km²) and 5 larger than 5,000 km² (277,282 km²). SM-Table 4, derived from the WDPA (UNEP-WCMC), used for this paper by permission.
People
About one person per km², measured. About 34,615 people live in the grid cells whose centres fall inside the nine strata (35,272 km² of cells), 0.98 per km². Measured on the 2020 epoch of the GHS-POP grid (release R2023A, 30 arc-second), 2026-09-30. Population: GHS-POP R2023A (Schiavina et al. 2023, doi:10.2905/2FF68A52-5B5B-4A22-8F40-C41DA8332CFE; Pesaresi et al. 2024, International Journal of Digital Earth 17(1)). © European Union, 1995-2025. Reuse of this data is authorised with proper acknowledgment of the source. The GHSL data are provided under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Clipped and aggregated from the original grid. It is a modelled grid, not a census. It agrees with the figure of "close to 1 inhabitant/km²" in the landscape description [SM Appendix A].
References
UNESCO World Heritage List, property 1380, Sangha Trinational, open-data dataset whc001, read 2026-09-30.
Ramsar Sites Information Service, Annotated List of Wetlands of International Importance: Congo; Cameroon; Central African Republic (rsis.ramsar.org), read 2026-09-30.
Dargie GC, Lewis SL, Lawson IT, et al. (2017). Age, extent and carbon storage of the central Congo Basin peatland complex. Nature 542: 86–90. doi:10.1038/nature21048
Crezee B, Dargie GC, Ewango CEN, et al. (2022). Mapping peat thickness and carbon stocks of the central Congo Basin using field data. Nature Geoscience 15: 639–644. doi:10.1038/s41561-022-00966-7
Potapov P, Hansen MC, Laestadius L, et al. (2017). The last frontiers of wilderness: tracking loss of intact forest landscapes from 2000 to 2013. Science Advances 3(1): e1600821. doi:10.1126/sciadv.1600821
Maisels F, Strindberg S, Blake S, et al. (2013). Devastating decline of forest elephants in Central Africa. PLoS ONE 8(3): e59469. doi:10.1371/journal.pone.0059469
Red List categories: Loxodonta cyclotis doi:10.2305/IUCN.UK.2021-1.RLTS.T181007989A204404464.en; Gorilla gorilla gorilla doi:10.2305/iucn.uk.2016-2.rlts.t9406a136251508.en; Pan troglodytes troglodytes doi:10.2305/iucn.uk.2016-2.rlts.t15936a17990042.en (categories only, read via Wikidata P141).
Schiavina M, Freire S, Carioli A, MacManus K (2023). GHS-POP R2023A — GHS population grid multitemporal (1975–2030). European Commission, Joint Research Centre. doi:10.2905/2FF68A52-5B5B-4A22-8F40-C41DA8332CFE.
Pesaresi M, Schiavina M, Politis P, Freire S, Krasnodębska K, Uhl JH, et al. (2024). Advances on the Global Human Settlement Layer by joint assessment of Earth Observation and population survey data. International Journal of Digital Earth 17(1).
Priority Species Index manuscript and Supplementary Material — the 2026-09-25 draft supplied to Landseed by the paper's authors (revision of 2026-09-29); unpublished and under review: Results, Discussion, SM Appendices A, B and E.
Overview
Species Index
Forest & swamp
Forest loss
People
Connectivity
Recovery
Global value
Reference maps
✕
scroll to zoom · drag to pan · double-click to reset
The landscape — nine WCS survey strata, and the Sangha Trinational around them
The landscape
Protected units
Relief
Satellite
Forest loss
Altitude bands
Cartographic plates rendered from open data — Elevation: produced using Copernicus WorldDEM-30 © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved (Copernicus GLO-30). The organisations in charge of the Copernicus programme by law or by delegation do not incur any liability for any use of the Copernicus WorldDEM-30. · Imagery: Contains modified Copernicus Sentinel data 2026 — Sentinel-2 L2A composite, 10 m · Survey strata: WCS Congo (Estienne et al.; Brncic et al.), cleared for public display · Neighbouring protected areas, water & roads: © OpenStreetMap contributors (ODbL) · Forest loss: Hansen/UMD GFC-2024 (Global Forest Watch) · International borders: OSM admin_level=2. Index figures from the Priority Species Index Supplementary Material, computed from the authors’ data rather than retyped; IUCN Red List categories only, transcribed from the Supplementary Material; this page does not carry the individual assessments.
Imagery: Contains modified Copernicus Sentinel data 2025–2026 — a median composite of 200 scenes, cloud-masked per pixel with the Sentinel-2 scene classification layer. 5.28% of the Likouala plate was never observed by any scene in the five-year search and is filled rather than imaged ; those pixels are not mapped separately, so fine detail on this plate is not a measurement everywhere. · Elevation: Copernicus GLO-30 (COP-DEM_GLO-30-PUBLIC). Produced using Copernicus WorldDEM-30 © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved. The organisations in charge of the Copernicus programme by law or by delegation do not incur any liability for any use of the Copernicus WorldDEM-30. · Survey strata: WCS Congo (Estienne et al.; Brncic et al.) · Neighbouring protected areas, water & roads: © OpenStreetMap contributors (ODbL) · Priority Species Index, from the paper's Supplementary Material · An independent visualisation by Landseed PBC. Not affiliated with, endorsed by, or produced for WCS, the Ministry of Forest Economy or the Government of the Republic of the Congo.
