Forest Block Research Articles

Cost-Effective Monitoring of Spruce Budworm Larvae

The spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is the most severe defoliator of balsam fir (Abies balsamea) in eastern Canada and northeast U.S.A. A large budworm outbreak is currently underway in the province of Québec, with 10.5 million hectares defoliated in 2023, up 14.1% from the year before. Populations of budworms are controlled using management guidelines of Forest Protection Strategy (FPS); the approach aims at killing defoliating larvae with aerial application of microbial insecticide, with the objective to limit defoliation and prevent tree mortality. The decision to treat/not treat a given forest block is based, in part, on local density of overwintering second instars (L2) collected at ca. 600 sampling points each year across the entire province at a cost of CAD 350 for three branches per site; the threshold for FPS (TFPS) corresponds to 20 L2/branch. Aerial defoliation maps also guide management decisions because FPS generally target areas within or in the vicinity of defoliated forest stands. Budworm abundance rapidly declines with distance to aerial defoliation (in km), to the extent that larval density rarely attains TFPS outside the core range of FPS (>15 km from defoliation). A cost-effective monitoring approach is proposed whereby forest blocks outside the core range of FPS are sampled every second year (as opposed to every year), representing a potential economy of CAD 40,000 annually.

Regeneration Status of Different Conifers in Gulmarg Forest Range of Kashmir Himalayas

The present study was concentrated in the four forest blocks, namely Khaipora, Tangmarg, Ferozpora and Baderkut of Gulmarg Forest Range in Kashmir Himalayas. Natural regeneration and edaphic factors affecting regeneration status of different conifers was studied. Quadrats of 2x2m in the main plot of size 50x20m were laid down to study the regeneration at four blocks of Gulmarg Forest Range. The maximum numbers of recruits (current year seedlings, less than height of 8 cm), unestablished (height more than 8cm to 200cm) and established (height more than 200cm) plants were found for Abies pindrow at all the sites with the exception at Ferozpora where unestablished plants of Pinus wallichiana were found highest. Highest establishment stocking per cent and regeneration success was found for Abies pindrow at Khaipora, Ferozpora and Baderkut. Overall regeneration success was found to be highest at Baderkut followed by Khaipora while as the lowest regeneration success was found at Ferozpora respectively. Simple correlation study reveal that the regeneration success has a significant positive relationship with Light Intensity, pH, Electric conductivity, organic carbon, available nitrogen and available potassium while as litter layer and available phosphorous had a significant negative correlation with regeneration success.

Miniature GPS tags reveal extensive movements by a threatened narrow‐space bat and highlight sensitivity to forest clearing

AbstractAn understanding of fine‐scale movements made by animals is critical for assessing localized habitat preferences and informing the scales over which land management should be applied. However, for cryptic species such as insectivorous bats that are highly mobile and active at night, it is difficult to collect these data. Nyctophilus corbeni serves as a case study for narrow‐space species as it is listed as threatened and nothing is known about its localized habitat preferences. We used miniature GPS tags to assess fine‐scale movements across three sites and 2 years (autumn 2020 and 2021) in the Pilliga forests in northwest New South Wales. Each site consisted of a mosaic of forest disturbances (e.g. timber harvesting / thinning regrowth, prescribed fires and wildfires, and cleared farmland). Bats made large movements in the non‐maternity season, with a maximum of ~21 km recorded as a one‐way movement on a given night. On average, the maximum distance travelled by tagged bats was 6.2 ± 1.4 km per night. Short‐term home (9884 ha) and core (2157 ha) ranges were extensive, but varied by sex, with ranges of females ~15 times larger than males. Bats crossed cleared land that was within close proximity (<2.3 km, but typically <~600 m) of large forest blocks (>100 ha). Based on availability of habitat types, bats selected for older regrowth and burnt forest and avoided cleared areas with scattered trees and also thinned forest, though the availability for the latter was low (<3 %). Flight speeds and the lack of clustering of GPS fixes in cleared landscapes suggest that limited foraging may occur there. Overall, our results highlight the sensitivity of the species to forest clearing and potentially to thinning, but also demonstrate the importance of maintaining large areas of forest and where possible, reforesting cleared areas that occur between smaller, more isolated forest blocks.

Community Lessons on Participatory Forest Management Performance within the Mau Forest Complex, Kenya

Forest resources are faced with challenges that range from mismanagement, overutilization, conflicts and competing claims. Consequently, this has given rise to legislation and policy to protect forests. However, many governments in developing countries have difficulties in implementing sustainable forest management (SFM). One of the strategies advocated to foster SFM is participatory forest management (PFM). The PFM approach has been practised formally in Kenya since 2005 when the Forests Act of 2005 came into force. The aim of this study was to assess PFM performance since the inception of three Community Forest Associations (CFAs), namely Nairotia, Nyangores and Olenguruone in the Transmara Forest Block within the Mau forest complex, Kenya. The data and information ranged from reviews from field meetings and in-depth focus group discussions with CFA members, Kenya Forest Service (KFS) officials and various key stakeholders. The results indicated that there are variations in results and progress towards PFM implementation in Kenya. While a number of activities had been carried out at each of the CFAs reviewed in the study, there was variation in terms of how the forest management agreements and plans were being implemented. In particular, the level of community and stakeholder participation, number of consultative meetings held and level of donor funding to facilitate participatory forest management plans (PFMP) development and project activities. A number of issues were also noted by CFAs as having been omitted in the management plans, specifically, benefit sharing. The absence of benefit sharing framework was cited often as a major drawback in PFM as it has constrained some of the anticipated benefits from forest activities. However, the community members indicated that there was improved awareness amongst them of the need to conserve the forest resources and controlled access to sustainable utilization of the forest resources

Vegetation composition and carbon stocks in West Batang Toru Forest Block, North Sumatra

West Batang Toru Forest Block, North Tapanuli Regency, North Sumatra Province is a forest that contains numerous species of tree stands and is estimated to be able to store a considerable high carbon from the atmosphere. The aim of this study was to determine the composition of vegetation and the potential for carbon stored in the forest region. This research was conducted from September 2021 to March 2022 using a purposive sampling method. Vegetation data were analyzed using the Diversity Index (H'), Uniformity Index (E) using the Shannon-Wiener equation. The carbon stock of each stand per species was estimated using the Ketterings’ allometric equation. The study documented a total of 64 families, belonging to 297 species with a total of 2,399 individuals. The percentage of composition of all growth rates ranged from 31%-59%. The Importance Value Index (IVI) of all growth rates ranged between 14.3 to 71.7%. The highest diversity index and evenness index at the tree level were 4.71 and 0.85. The stored carbon is 373.227 tons C/ha in West Batang Toru Forest Block, highlighting the forest region as an important green carbon sink.

ANALYSIS OF THE INFLUENCE OF CHANNELS DISTANCE ON WATER BALANCE CALCULATIONS IN THE LIANG ANGGANG PROTECTED FOREST AREA BLOCK 1

Peatland is an ecosystem that easily catches fire when dry. The highest number of forest fires was found in Banjar Regency, Banjar Regency, and Tapin Regency. One of the factors causing peatland fires in the Liang Anggang Protected Forest, apart from human activity, is the occurrence of drought, where more water is lost than water that enters the land. This study aims to analyze the water balance with the influence of the drought index on peatlands that are fibers and have canals based on the equation in Thompson's study (2014). The data used in the water balance research are monthly rainfall data, and monthly temperature data from 2000 to 2021 obtained from the Class II Meteorological Station Syamsuddin Noor Banjarmasin, then forest intercept is 16.4% based on research from Vernimmen (2007), calculations evapotranspiration (ET0), and storage changes in the unsaturated zone (Δϴ) with the modified Keech-Byram Drought Index value approach with the condition of the physical properties of fibers peat soil. The highest rainfall occurred in January 2021, 898.7 mm/month. The maximum average evapotranspiration (ET0) occurs in February, with a value of 100.3 mm/month. Based on the calculation of the water balance in the Liang Anggang Protected Forest Block 1, there was a water deficit from July to October, with the peak of the water deficit occurring in September, which was 65.6 mm/month and the peak of the water surplus in February, of 211.8 mm/month. Keywords: Interception, Evapotranspiration, Water Balance, Liang Anggang Protection Forest

Evaluation of Infiltrated Water Volume in the Liang Anggang Protected Forest Block 1

The Liang Anggang Protection Forest is an area formed from peat soil. Peat soils have a role to play in conserving water resources, reducing flooding, preventing seawater seepage, and so on. Damage to the water system in peat soils is often caused by individual activities that are not well controlled. This is thought to have resulted in the depletion of water in peat soils, causing the soil to become dry and flammable in the dry season. The purpose of this research is to examine the rate of water infiltration in Liang Anggang Protected Forest Block 1. In this study, the method used in analyzing the infiltration rate was the Horton method by measuring the infiltration rate using a double-ring infiltrometer (turf-tec infiltrometer). According to the study's findings, the average decrease in infiltration rate of test 1 on bare or low-density land is 12.4 cm/hour, medium-density land is 2.7 cm/hour, very dense, closed, or forested land is 3.6 cm/hour, and test 2 on barren land is 2.4 cm/hour, medium density land is 2.7 cm/hour, and very dense, closed, or forested land is 4.7 cm/hour. Keywords: Double ring infiltrometer, Infiltration Rate, Horton Method, Liang Anggang Protection Forest

Survey of Wild Fruits Consumed by Animals in the Forest Block of Ubangi Eco-region, Democratic Republic of the Congo

An ethnobotanical survey was carried out in Gbado-Lite city (Province of North Ubangi) in the Democratic Republic of Congo, among 74 hunters and bushmeat sellers in order to inventory the wild fruits consumed by animals in the forest block of the Ubangi eco-region. Data were collected using a semi-structured questionnaire containing questions that could provide information on each plant species and its main consumers. The results reveal that the majority (41.8%) of respondents live in the Kaya neighborhood. 27% of female informants live in the Mbanza neighborhood, 10.8% in the Pangoma neighborhood, and 9.7% in the Lite neighborhood. The majority of respondents were men (89.1%), while women accounted for only 10.9%. As for marital status, married people (70.2%) and widowers (14.8%) are the most represented. Hunting and the sale of bushmeat (44.5%) and agriculture (41.8%) are the main activities carried out by the respondents. The diversity of the wild flora is composed of 19 species of fruit plants, distributed in 19 genera and 16 botanical families. The main families of wild fruit plants consumed by wildlife are Malvaceae, Meliaceae, and Urticaceae. As for the wildlife, the animals inventoried belong to five classes, mammals (76.9%), Reptilia (7.8%), Aves (7.8%,) and Polyplacophara (7.8%). The fauna studied is composed of 12 families of wild animals, the most abundant of which are Bovidae (27.5%), and Nesonyidae (10.0%). It is necessary that chemical and pharmacological studies be carried out on these plant taxa in order to evaluate their medicinal and food values. The domestication of these plant species should be part of the subsequent studies to ensure the sustainability of the wild fauna. Thus, the integration of local wild edible fruit plants into agroforestry systems is the best solution to combat their disappearance in the Ubangi ecoregion, which is faced with traditional slash-and-burn agriculture.

Tree architecture model of Sumatran Orangutan Pongo abelii Lesson, 1827 (Mammalia: Primates: Hominidae) nests at Soraya Research Station, Leuser Ecosystem, Indonesia

The relationship between tree architectural models and the nesting behavior of the Sumatran Orangutan Pongo abelii Lesson, 1827 at the Soraya Research Station, Sumatra, Indonesia was determined by examining the preference for particular nest tree architectural models in relation to the frequency of nest occurrence. This investigation included the study of tree architectural models, tree types, nest profiles, vegetation, environmental factors, and geospatial data, collected within a 20 × 1,000 m (2 ha) observational area during a nest survey. A total of 59 orangutan nests were identified across 47 trees, categorized into 31 species and nine varied tree architectural models. Among these, the most prevalent models observed were Cook, Scarrone, and Attims, which exhibit features assumed to enhance orangutan nesting behaviors. Based on the Neu approach to nest qualities, the analytical test findings show a correlation between the preference ratings for nesting trees. Our results are expected to serve as a reference for selecting tree species in rehabilitation or habitat restoration programs and the development of separated forest block corridors as conservation efforts for orangutans.

A Contribution to the Flora of Sariska Tiger Reserve, Alwar District, Rajasthan

Sariska Tiger Reserve, one of the 15 Tiger reserves of India, is located in the undulating plateau lands and wide valleys of the hill ranges of Aravalli system, near the civil district of Alwar in Rajasthan. Established in the year 1978-79, it is about 140 km from Jaipur on Jaipur-Delhi State Highway and spreads over a total area of 800 sq. km with a core area of 498 sq. km. The reserve consisting of 37 forest blocks is a classic example of a rare amalgamation of natural history and archaeology. The 9th and 10th century ruins of the Siva temple of Grah Rajer, the Mediaeval fort of Kankwari and the Tomb of Lord Bhartrihari add to the grandeur of this reserve which abounds in wild life. The paper deals with a short history, Topography, Fauna & Vegetation of the area.

Identification of Forest Fire Affected Area and Burn Severity Analysis in Bankati Forest Block of Dudhwa National Park, Uttar Pradesh Using Geospatial Techniques

Identification of Forest Fire Affected Area and Burn Severity Analysis in Bankati Forest Block of Dudhwa National Park, Uttar Pradesh Using Geospatial Techniques

Woody Species Composition, Stand Structure and Regeneration Status of Londiani Forest in Kenya

Tropical forests provide habitats for diverse flora and fauna, in addition to playing a crucial role in climate regulation. They are being recognized for their roles as nature-based solutions to many sustainable development challenges, as shown by increased political commitment and global promises to reduce the rates of deforestation and boost the restoration of degraded forest ecosystems. Understanding tropical forest dynamics and their conservation status is therefore important. This study analysed the forest stand structure, the tree species composition and the regeneration status of Londiani Forest. In the three blocks of Londiani Forest, which are Kedowa, Chebewor and Londiani, belt transects that were 25 m wide and 1 km long were established. At every 200 m along the transects, 25 m × 25 m quadrats were set up in which an inventory of all the tree species was determined. Diameter tape was used to measure the diameter at breast height (DBH) 1.3 m above the ground. With the use of a Suunto angular clinometer, the tree height was measured. A nested 5 m × 5 m quadrat within the 25 m × 25 m quadrat was used to sample the saplings, while a 1m × 1 m quadrat was used to sample the seedlings. The quantities of seedlings and saplings were used to determine the state of regeneration. The data were entered into Microsoft Excel. The total stem density, species density, basal area, species basal area, relative density and species diversity were determined and extrapolated per hectare. A total of 1308 distinct trees from 34 different species and 24 families were counted. Kedowa recorded the highest (27) species richness, followed by Chebewor (19) and then Londiani (14). There was a statistically significant difference in the species richness among the three forest blocks (p < 0.05). Within the three forest blocks, there were no statistically significant variations in the basal area distribution (p > 0.005) or in the mean DBH (F = 0.560; p = 0.729) or height class distribution (F = 0.821; p = 0.558). There was a statistically significant difference in the stem density (F = 12.22; p = 0.005) and woody species diversity (F = 0.32; p = 0.001) within the three forests blocks. The similarity index ranged from 0.34–0.47. The presence of substantial numbers of seedlings and saplings in all forest blocks was an indication that there was regeneration.

Preserving large blocks of primary forest is critical to conserve forest‐dependent bird species in the Amazon

AbstractResearch Highlight: Birch, B. D. J., Mills, S. C., Socolar, J. B., Martínez‐Revelo, D. E., Haugaasen, T., & Edwards, D. P. (2024). Land sparing outperforms land sharing for Amazonian bird communities regardless of surrounding landscape context. Journal of Applied Ecology, https://doi.org/10.1111/1365‐2664.14596.Tropical forests are globally threatened by agricultural activities, including cattle farming. The land sharing versus land sparing debate has often been used as a means of addressing the trade‐off between agricultural production and biodiversity conservation, without finding a consensus within the scientific community. Moving forward, recent studies suggest combining both land allocation strategies, where wildlife‐friendly habitats within farmlands could allow movements of species within the agricultural matrix and connect natural habitats such as forest blocks, though this has rarely been demonstrated with empirical studies. In their study, Birch et al. tested how wildlife‐friendly habitats within and around cattle pastures could rescue the negative effects of converting forest to farmland on Amazon bird communities. To do so, they modelled bird species occupancies and simulated different land sharing versus land sparing scenarios with varying amount of landscape‐scale wildlife‐friendly habitat and levels of production. They found that the land sparing strategy outperformed land sharing in all scenarios, with limited benefits of landscape‐scale wildlife‐friendly habitat. This result was mostly driven by forest‐dependent species that cannot persist in farmlands. As these species are highly sensitive, preserving large blocks of primary forest is critical for their conservation.

Structure, Composition, Carbon Stocks of Dipterocarpaceae in West Batang Toru Forest Block, North Tapanuli Regency, North Sumatra

The West Batang Toru Forest Block in the North Tapanuli Regency, North Sumatra, is one of the lowland forests in Sumatra with a variety of plant communities and populations that have not been fully documented. This area is considered a potential high-value carbon reserve of ecological significance. The purpose of the study was to determine the structure and composition of the Dipterocarpaceae at the West Batang Toru Forest Block. This research was conducted from September 2021 to March 2022. The research location was determined by using the purposive sampling method with a transect length of 300 m. Each lane had plots of 20 × 20 m measured in a zigzag position and had an interval of 10 meters. The number of plots in each lane was 10, for a total of 90 plots. Based on the observations, there were nine species of Dipterocarpaceae obtained from a total of 621 individuals. The basal area ranged from 578.02 cm2/Ha to 397,894.43 cm2/Ha, and the largest basal area was at the tree level. The vegetation composition ranged from 60% to 66%, and the highest composition was at tree level. Sixty-two trees were classified as having the largest basal area, followed by poles (42 individuals) and saplings (64 individuals). Shorea platyclados occurred consistently with a compositional percentage value at the tree level with a value of 66%, the pole level of 53%, the sapling rate of 34%, and the seedling level of 9%. The carbon stocks from Dipterocarpaceae stands were 91534 tons/ha, which is the first estimate of their ecological importance

Land sparing outperforms land sharing for Amazonian bird communities regardless of surrounding landscape context

AbstractTwo strategies are central to the debate regarding agricultural development: one integrates farming and conservation (land sharing), and the other separates farming and conservation, intensifying production to allow the offset of natural habitat (land sparing). The role of wildlife‐friendly habitat in the wider surrounding landscape (landscape wildlife friendliness (WF)) in promoting farmland diversity is potentially an unexplored benefit of land sharing.We sampled birds across primary forests and cattle pastures in the western Amazon, where terrestrial biodiversity peaks. We tested the hypothesis that increased landscape WF will lead to increased species richness (SR) on farmland, even at low levels of ‘on‐farm’ wildlife‐friendly habitat (farm WF).We show that while there is a minor increase in SR linked to increased levels of landscape WF, a large component of the avian community is functionally absent. Most forest‐dependent species are missing from pasture, even at high levels of farm WF. For these species, the preservation of blocks of contiguous forest under land sparing is vastly superior.We modelled both strategies under different levels of production. Land sparing always retained significantly higher SR than land sharing, regardless of the level of landscape WF.Synthesis and applications. Landscape wildlife friendliness (WF) provided through land sharing is of limited benefit to many tropical forest‐dependent species that are unable to move across or utilise pasture, even at high levels of farm and landscape WF. To ensure the persistence of these species, policymakers should urgently implement sustainable intensification mechanisms to increase farmland productivity while enabling the protection of large blocks of spared natural habitat.

Floristic and structural distinctness of monodominant Gilbertiodendron dewevrei forest in the western Congo Basin

Background and aims – The forests of the Congo Basin contain high levels of biodiversity, and are globally important for carbon storage. In order to design effective conservation strategies, and to accurately model carbon stocks, a fine-scale understanding of the different forest types that make up this forest block is needed. Monodominant Gilbertiodendron dewevrei forest covers large areas of the Congo Basin, but it is currently unclear whether it is sufficiently distinct from adjacent mixed terre firme forest to warrant separate treatment for conservation planning and carbon calculations. This study aimed to compare the structure and diversity of monodominant and mixed forest, and ask whether there is a unique vascular plant community associated with G. dewevrei forest. Material and methods – We utilised a combination of plot data and herbarium specimens collected in the Sangha Trinational (a network of protect areas in Cameroon, Central African Republic, and the Republic of Congo). Plot inventories were used to compare G. dewevrei forest and mixed forest for stem density, basal area, above ground biomass, stem size distribution, species diversity, and species composition. In addition, a database of 3,557 herbarium specimens was used to identify species of vascular plant that are associated with G. dewevrei forest. Key results – Gilbertiodendron dewevrei forest is distinct in both structure and species composition from mixed forest. Gilbertiodendron dewevrei forest has a lower stem number (of trees ≥ 10 cm), but a greater proportion of larger trees (> 70 cm), suggesting higher carbon stocks. The species composition is distinct from mixed forest, with 56 species of vascular plant significantly associated with G. dewevrei forest. Conclusion – Monodominant G. dewevrei forest in the Sangha Trinational is both compositionally and structurally distinct from mixed forest. We therefore recommend this forest type be considered separately from mixed forest for conservation planning and carbon stock calculations.

Invasion by Cedrela odorata threatens long distance migration of Galapagos tortoises.

Invasive alien species are among the most pervasive threats to biodiversity. Invasive species can cause catastrophic reductions in populations of native and endemic species and the collapse of ecosystem function. A second major global conservation concern is the extirpation of large-bodied mobile animals, including long-distance migrants, which often have keystone ecological roles over extensive spatial extents. Here, we report on a potentially catastrophic synergy between these phenomena that threatens the endemic biota of the Galapagos Archipelago. We used GPS telemetry to track 140 migratory journeys by 25 Western Santa Cruz Island Galapagos tortoises. We plotted the spatial interaction between tortoise migrations and recently established non-native forest dominated by the invasive tree Cedrela odorata (Cedrela forest). We qualified (a) the proportion of migratory journeys that traversed Cedrela forest, and (b) the probability that this observed pattern occurred by chance. Tortoise migrations were overwhelmingly restricted to small corridors between Cedrela forest blocks, indicating clear avoidance of those blocks. Just eight of 140 migrations traversed extensive Cedrela stands. Tortoises avoid Cedrela forest during their migrations. Further expansion of Cedrela forest threatens long-distance migration and population viability of critically endangered Galapagos tortoises. Applied research to determine effective management solutions to mitigate Cedrela invasion is a high priority.

The main forest species encountered in southern and central Benin, West Africa.

The south of Benin, a country in West Africa, is still home to remnants of dense forests that benefit from a particularly rainy sub-equatorial climate, with annual rainfall of up to 1,200 mm. These forest ecosystems are an integral part of the West African forest block, which stretches from Liberia to Togo. However, despite their richness and ecological importance, these forests are unfortunately subject to strong human pressures, particularly from slash-and-burn agriculture, intensive logging and the growing urbanisation of coastal areas. Preserving these forests is crucial, however, as they are home to remarkable plant and animal biodiversity, with many endemic species. What's more, these forests play an essential role in regulating the local climate, protecting soil and water resources, as well as providing local populations with a vital source of energy wood, non-timber forest products and support for their traditional agricultural practices. Faced with these conservation challenges, identifying and characterising the main tree species found in the forests of southern and central Benin, forest species and their ecology is an essential prerequisite for implementing sustainable management and restoration strategies for these threatened forest ecosystems in southern Benin. This work aims to identify and draw attention to the different forest species, specially tree forest species present in southern and central Benin. The dataset provides information on forest species found in southern and central Benin, West Africa. This dataset is extremely useful for forestry research, as it focuses mainly on the various forest species of major importance. It can be used as a basis for characterising individuals or populations of species, based on their abundance in relation to anthropogenic pressure and changes in environmental conditions.These species are characteristic of forests and, above all, are of particular interest both to populations and to managers of protected areas. Field collections were initiated in 2007 as part of natural forest inventory work. The data collected have been completed by various field works that followed this work on forest species in southern Benin. The latest version of the dataset is publicly and freely accessible on the GBIF website at the address https://www.gbif.org/dataset/aff3a10a-a86b-4eff-98e4-d63f92fd6f7e.It should be noted that the fact that the collection and monitoring were carried out in southern Benin, a region known for its great diversity of species, over a period of 10 years making these data particularly relevant information to study the effects of climate change and human pressure on ecosystems in this area.

New surveys reveal a population stronghold for the Hoary-throated Spinetail Synallaxis kollari and Rio Branco Antbird Cercomacra carbonaria along the Guyana–Brazil border

Summary The hoary-throated spinetail and Rio Branco antbird are two bird species endemic to the Rio Branco drainage of Brazil and Guyana, currently listed as Critically Endangered on the IUCN Red List. Previous assessments of both species’ global populations focused on the Brazilian state of Roraima but did not include most of its border with Guyana, where significant areas of suitable habitat remain along the Ireng (Maú) and Takutu (Tacutu) Rivers. In July and August 2021, we conducted a survey to determine the extent of each species’ geographic range along the two rivers, and to estimate population sizes. We used playback surveys along 219 km of river to ascertain each species’ distribution and intensively sampled three forest blocks to determine densities. Both species were locally abundant on both sides of the international border. Rio Branco antbird occurred over a greater geographic range than hoary-throated spinetail, particularly along the Takutu River, but was confined to a narrower zone along the river edges. Both species appear to have retreated from habitat along the Ireng River that was occupied in the past, possibly due to habitat degradation from increasingly frequent fires. Nevertheless, our minimum estimates of 1147 antbirds and 851 spinetails in the study area represent, respectively, 7.5% and 17.8 % increases over current estimates of global population sizes, and indicate that the Guyana-Brazil border region may become a critical stronghold for both species if effective conservation measures are implemented. We propose establishment of a Key Biodiversity Area encompassing the core of both species’ distributions along the border; extensive follow-up work including stakeholder engagement to explore possibilities for habitat management and protection; and further field study to increase general ecological knowledge of these two bird species.

Projecting forest cover in Madagascar's protected areas to 2050 and its implications for lemur conservation

AbstractPredicting future conservation needs can help inform conservation management but is subject to uncertainty. We measured deforestation rates during 2015–2017 for 114 protected areas in Madagascar, linked deforestation to the status of protection according to IUCN categories I–VI, used recent deforestation rates to extrapolate forest cover over 2017–2050 and linked the size of forest blocks to the projected persistence of lemur subpopulations. In the six IUCN categories for protected areas in Madagascar the median size of forest blocks is 9–37 km2 and median annual deforestation rates range from 0.02% in the single IUCN category III site to 0.19% in category II and 1.95% in category VI sites. In 2017, 40% of all forest blocks within protected areas were < 10 km2, and this is projected to increase to 45% in 2050. Apart from these small forest fragments, the modal site of forest blocks was 160–320 km2 in 2017, and this is projected to decrease to 80–160 km2 in 2050. The range of > 50% of all lemur species exclusively contains forest blocks of < 10 km2. The modal size of forest blocks > 10 km2 is predicted to remain at 120 km2 until 2050. Although uncertainty remains, these analyses provide hope that forest blocks within the protected areas of Madagascar will remain large enough to maintain lemur subpopulations for most species until 2050. This should allow sufficient time for the implementation of effective conservation measures.