Bladen Nature Reserve

Bladen Nature Reserve in Belize is a landscape of caves, sinkholes, streams and rivers, old growth rainforest and an abundance of highly diverse flora and fauna which includes a great deal of rare and endemic species.

Widely described as the crown jewel of Belize's protected areas, Bladen is considered to be one of the most biodiversity-rich, and geographically unique areas within the Mesoamerican Biological Corridor. At Bladen forms a significant portion of the Key Biodiversity Area of the Maya Mountains which was identified as one of the most important blocks of protected areas within Belize and more broadly, Mesoamerica, itself a region considered a world ‘hotspot for species diversity’Conservation International (2003) Biodiversity Hotspots - Mesoamerica. www.biodiversityhotspots.org and considered critical for the preservation of the biodiversity of the Western Hemisphere.

At its most sheltered points, west of the rugged karst (limestone) hills, Bladen has protection from many of the destructive storms that hit the Caribbean coastline, resulting in a forest with a little-disturbed structure, tall trees of impressive stature and intact ecosystems. The large number of ecosystems encompassed within the nature reserve highlights its importance as a strictly protected conservation area. Bladen protects species diversity across a great range of elevations, which according to recent evidence includes several potential new and endemic species.

Within the Maya Mountains, Bladen forms a crucial link between Cockscomb Basin Wildlife Sanctuary to the northeast and Columbia River Forest Reserve to the southwest. Chiquibul National Park and Forest Reserve lie to the northwest, connecting to the protected areas system in Guatemala. With the rapid clearance of forested areas throughout Central America, this is part of the last remaining large, relatively intact block of forest within the region – the Selva Maya - stretching from Belize through to Guatemala and Mexico.

This large expanse of primarily forested uplands and valleys is essential for the survival of species such as the jaguar, scarlet macaw, white-lipped peccary and harpy eagle, which need large contiguous forest stretches in order to maintain viable populations.

Management

Bladen is one of three nature reserves within Belize, and is managed through partnership between the Government of Belize and the Ya'axché Conservation Trust (Ya’axché). Ya’axché took over management in December 2008 and has a letter of intent from the Belize Forest Department to co-manage the protected area. Ya'axché now assumes responsibility for the day-to-day management of the reserve.

Characteristics

Ecosystem Services

Bladen Nature Reserve provides global environmental benefits by providing clean air, functioning as a carbon sink, rainfall generation, and preserving genetic diversity. On a more local scale Bladen functions as a sanctuary for birds and mammals which are subject to hunting for bushmeat, with this large contiguous block of undisturbed rainforest these game species are able to increase population size thus creating a ‘spillover effect’ onto community lands where they may be hunted as a source of protein by indigenous Mayan communities which buffer Bladen and who have traditionally lived off the products of these forests.

Bladen Nature Reserve's role in watershed protection within the area is also important, with the river system providing water for local communities and large agricultural areas on the coastal plain. The watershed drains into the Caribbean Sea to the east, with the Belize Barrier Reef - the second largest barrier reef in the world - lying offshore, reliant on the quality of the water. Bladen, along with Cockscomb Basin Wildlife Sanctuary protects the upper waters and tributaries of the Monkey River, ensuring that it provides the major benefits of watershed protection and management to the coastal plain areas, including water supply, water quality, flood control, sediment control, quality of fish stocks, biodiversity, and habitat preservation. Furthermore, Bladen protects the steeper slopes of the watershed areas, which, if cleared, would cause rapid erosion and sedimentation problems, not only within the river system downstream, but also on the sea grass and out on the fragile coral reef.

Geology and landforms

Bladen Nature Reserve encompasses much of the Upper Bladen Watershed, and is composed essentially of two geomorphological areas - the granite / volcanic slopes rising to the crest of the Maya Divide to the north west, and the limestone karst to the south, both draining into the flat, alluvial plain of the Bladen Branch itself. Between these two, lies the Bladen Branch valley, draining to the northeast.

The geology of Bladen follows this general topography, being divided into two geomorphological areas running parallel to each other. The ridge of metamorphosed sedimentary rocks, known as the Santa Rosa Group, with localized granite intrusions, is part of the main Maya Mountain range, which was subjected to tectonic uplift along two major fault systems – the Northern Boundary Fault to the north, and Quartz Ridge / Bladen Fault during the Triassic period, accompanied by intrusion by granite. In the early Cretaceous period oceanic waters flooded the area and fossiliferous limestones were deposited over the entire Maya Mountains.

The beginning of the Paleogene Period (65 million years ago) saw renewed tectonic uplift of the Maya Mountains (Table 5) resulting in the formation of an upland plateau, and shaping the present topography of the Maya Massif. This plateau dips gently to the west, whilst the steep eastern edge of this plateau has been eroded by numerous streams to form the series of steep sided valleys leading down from the Maya Divide, that form the relief in Cockscomb, Bladen and Columbia Forest.

To the east and south-east lies rugged limestone topography of steep, conical hills pocked by vertical-sided sinkholes, underground streams and caves. Water is scarce in this karst landscape, especially during the dry months, resulting in the presence of a vegetation type adapted to seasonally drier conditions, and a seasonal migration of wildlife to the lowlands. Smaller streams that emerge as springs within the hill slopes then disappear underground again after flowing a short distance – a characteristic of this limestone topography. Only the Bladen, flowing over the porphrytic Bladen Volcanic Member (an area composed of lavas and associated extrusive volcanic sediments that lies between the Santa Rosa Group and the limestone hills), runs permanently throughout the year.

Soils

Two major soil and land use studies have taken place in Belize – the first a comprehensive study of the whole country by Wright ''et al.'' (1959), looking at soils and associated vegetation assemblages in great detail. The second is a more recent study by King ''et al.'' (1986) based on Wright ''et al.'' (1959) but using techniques such as satellite imagery to update the original report. Soils within Bladen are dependent on the underlying geology, and can be divided broadly into soils derived from limestone rocks, and those with granitic origins.

Constantly Lime Enriched Soils and Intermittently Lime Enriched Soils: These are soils of the Toledo Foothills - densely dissected, steeply sloping limestone hills. Much of the land consists of karst topography of sloping towers and sink holes, produced by differential limestone solution. The steeper regions are very prone to erosion, and therefore unsuitable for agriculture.

Acidic Soils: These acidic soils are derived from the granite upland areas of the Richardson Peak Mountains Land System that form the western slopes of the Bladen Basin. These steep mountainous slopes of the Maya Mountains – over 25° angle between altitude, overlie Santa Rosa Group metasediment rocks, producing non-alluvial, shallow soils on the slopes, or deeper colluvial deposits that collect at the base of the hillslopes following erosion. Vegetation characteristic of this soil type is evergreen broadleaf forest, shrubland and pine at higher altitudes.

Recent Soils: The most recent soils are in the north-east of Bladen, following the line of the floodplain of Bladen Branch and Richardson Creek, and laid down by these streams as they drain the Richardson Peak Mountains and karst hills to either side, and also the volcanic porphyrite. These fertile, alluvial soils are built up by regular flood events, with the characteristics of the Toledo Floodplain soils, and have led to incursions into the area by people wanting to settle new farming areas.

Hydrology

The Upper Bladen drainage is a tributary of the Monkey River, the fourth largest watershed catchments in Belize with an estimated drainage area of . In the upper reaches, on the south-east slope of the Maya Divide, the water flows off steep terrain, carving deep valleys through the landscape, and is protected within three contiguous protected areas – Bladen Nature Reserve, Cockscomb Basin Wildlife Sanctuary and Maya Mountain Forest Reserve. To the south, this drainage basin is bordered by karstic ridge crests. Within Bladen, this trellis of fast flowing streams meet to form Bladen Branch, draining the extruded Bladen volcanic rock and limestone to the one side, and the granite and sedimentary rock to the other, flowing through an alluvial plain and meandering eastwards, exiting the protected area, and flowing on to join the Swasey on entering the coastal plain.

To the south-east, a limited number of the karstic streams form the headwaters of Golden Stream, and to the south east, the Rio Grande watersheds.

Of the three water system categories – upper reaches (headwaters), middle reaches, and lower reaches (estuarine) - only two (upper and middle reaches) are represented within Bladen, as the protected area has no direct contact with the coastal areas. The majority of the streams and creeks draining the hill slopes within Bladen fall within the upper, or ‘headwaters’ category, characterized by fast running streams, waterfalls, pools and riffles, often carved deep into the bedrock, with tropical broadleaf forest on either bank, branches meeting overhead and shading the water.

These upper reach streams then join to form Bladen Branch further downstream in the middle reaches of the river system, the water flowing through a narrow floodplain, with little variation in gradient. The character of the waterway changes from the fast moving streams of the headwaters to slower, wider, deeper, meandering rivers, interspersed in places with shallower riffles.

Dependent on the geology of the area, the river systems of the Monkey River watershed can be divided into two different categories - those rivers that drain granite and Santa Rosa Group metasediments (tributaries of South Stann Creek, Swasey Branch and Trio), and those that drain the Bladen volcanic rock and surrounding limestone (Richardson Creek and other southern tributaries of Bladen Branch). The water of rivers draining the granite and metasediments is rich in phosphorus, though with low nitrogen levels, low conductivity and a basic pH. Conversely Bladen Branch, draining the volcanic rock and adjacent limestone, is low in phosphorus, but has a higher level of nitrogen, high conductivity, and a neutral pH.

The differing phosphorus levels have a very strong bearing on the flora and fauna found within these rivers (Esselman, pers. com.). Phosphorus is particularly important as a plant growth promoter in freshwater systems, resulting in more abundant aquatic plant life (especially Marathrum oxycarpum), providing greater shelter and food resources, enabling greater aquatic invertebrate abundance and biomass – which can be expected to result in an increased abundances and biomass of fish. M. oxycarpum is present at elevated levels in South Stann Creek, Swasey Branch and Trio Branch, all of which drain areas of granite and metasediments, and can be expected to show far greater abundance of plant life than the phosphorus-poor Bladen Branch and Richardson Creek.

Habitats

The forests of Bladen Nature Reserve are evergreen in the valleys and on the lower slopes, semi-evergreen (25-50% deciduous trees) on the upper slopes, and semi-deciduous (5-75% deciduous trees) on the ridge. Forest stature decreases with increasing elevation from the valleys to the ridges, with a corresponding decrease in the density of large trees. This largely reflects edaphic drought associated with rapid drainage on the steep limestone topography. Recent studies of phytogeography have demonstrated a significant affinity between the flora of the Greater Antilles and the upper limestone ridges of the Bladen Nature Reserve, indicating a far more complex regional phytogeography than previously suspected.Brewer S. W., M. Rejmanek, M.A.H. Webb and P.V.A. Fine (2003). Relationship of phytogeography and diversity of tropical tree species with limestone topography in southern Belize. Journal of Biogeography 30, 1669-1688

Twenty ecosystems have been identified within the Bladen area, ranging from broadleaf lowland hill forest to submontane forest, riparian shrubland and short grass savannah.

At the ecosystem level, the Bladen Nature Reserve plays a critical role as a core conservation area, protecting over 5% of the national extent of 11 ecosystems. 10 of these ecosystems have more than 15% of their total national coverage within the protected area, 5 of which have over one third of the total national coverage occurring within the boundaries of Bladen Nature Reserve. Each of these ecosystems is confined to rugged terrain in the higher rainfall areas of southern Belize.

Flora

With its diversity of altitude, geology, aspect and hydrology, Bladen Nature Reserve offers perhaps the most diverse range of conditions for plant life of any protected area in Belize (Figure 7). A significant portion of the plants recorded to date are specialists – associated with a narrow ecological zone. This complexity is enhanced by the seasonality experienced by the limestone substrata and associated soils (Brewer ''et al.'' 2003). Whilst the 1994 REA recognized only 9 ecosystems (as compared with the 20 mapped by Meerman & SabidoMeerman J.C. & Sabido, W. (2001). Central American Ecosystems Map: Belize. Programme for Belize.), they found that 73% of the approximately 300 plant species they identified were specific to single ecosystems. This suggests a far higher prevalence of ecological specialization in the flora of Bladen than is typical in Belize. Plant associations are reported to link the flora of some of the upper elevations within Bladen with the flora of the Antillean archipelago (S. Brewer, pers. com.). A number of plant species that occur in these upper elevations of Bladen and the contiguous portions in Chiquibul National Park are found nowhere else in Belize (J. Marlin, pers. com.).

Whilst the lowlands of Bladen were repeatedly logged, albeit at low levels, up until about 1970, the steep terrain of much of the reserve was not conducive to extensive logging