Road Transects Research Articles

Harmonizing ecology and society: an integrated analysis of vulture conservation in the Nilgiri Biosphere Reserve, India

The Nilgiri Biosphere Reserve (NBR) in southern India is home to several critically endangered vulture species. This study in Mudumalai Tiger Reserve and Sathyamangalam Tiger Reserve of NBR presents an integrated analysis of vulture conservation efforts focusing on harmonizing ecosystem preservation and community engagement. We assessed the current status of all four vulture species in the NBR using the road transect method, covering 2,040 km with 24 replications (January–December 2021). We undertook covert surveys in 82 veterinary pharmacies across four districts of Tamil Nadu to determine the availability of non-steroidal anti-inflammatory drugs (NSAIDs), considering the 100-km vulture safe zone that included vulture nesting and foraging areas. As practical conservation efforts require active local community participation, our assessments include the perception study of local communities in 20 villages (eight tribal and 12 non-tribal) near vulture habitats. We focused on NSAID usage, considering the impact of numerous socio-economic factors on vulture conservation efforts. We surveyed 540 respondents using detailed questionnaires for these evaluations. The study underlined the need for a comprehensive vulture management plan that balances ecological concerns with the well-being and means of subsistence of surrounding communities. This study is helpful for future conservation efforts in other areas with comparable problems at the nexus of ecology and society.

Comparative Assessment of Plant Species and Their Taxa Distribution between the Capital Cities of Akwa Ibom and Bayelsa States, Nigeria

The study examined the comparative assessment of plant species and their taxa distribution between the Capital Cities of Akwa Ibom and Bayelsa States, Nigeria. The study established quadrats of 30mx200m along road (transects) in GRAs of Uyo City, Akwa Ibom State and Yenagoa City, Bayelsa State labelled as sampled sites and a quadrat of 100mx100m were established as control sites (secondary forest) at a minimum of 300m from the sampled sites. Descriptive statistics were employed to analyse the data. Findings revealed that that a total of 32 plant individual species types were found in the sampled sites in Uyo while a total of 16 plant individual species types belonging to 13 families were found in Yenagoa. Also, the 32 individual plant species found under the sampled sites belong to 20 families with Arecaceae and Moraceae having the highest species individuals in Uyo Town while 26 individual plant species were identified belonging to 19 families with Apocynaceae and Guthiferae producing the highest numbers of species individuals in Yenagoa. The study can be concluded that there was variation in the plant taxa between Akwa Ibom State and Yenagoa State as the plant composition in the Uyo is more than that of Yenagoa Town suggesting the influence of the level of urbanization and other anthropogenic activities. The study recommended that urban greening activities should commence immediately in the areas where there is a shortage of plant composition.

Integration of Indigenous Research Methodologies, Traditional Ecological Knowledge and molecular scatology in an assessment of mesocarnivore presence, diet and habitat use on Yurok Ancestral Lands.

Partnerships between Tribes and researchers in wildlife monitoring and application of Traditional Ecological Knowledge (TEK) have taken a variety of forms, and some scholars have noted a need for culturally sensitive approaches. Guided by Indigenous Research Methodologies, this research is coupled with Yurok TEK, or hlkelonah 'ue-megetohl ('to take care of the earth'), enabling an applied, culturally sensitive approach in partnership with the Yurok Tribe. We present results from a molecular scatology study of wildlife within the ancestral territory of the Yurok Tribe. Scats were collected opportunistically on road transects. All samples (N = 132) were analysed via DNA barcoding and results matched to documented 'Oohl 'we-toh (Yurok language) names to determine the depositor species (N = 8). Though there were four focal mesocarnivore species in our study, only bobcat (Chmuuek; Lynx rufus) and gray fox (Wergers; Urocyon cinereoargenteus) were detected as depositor species. Post hoc analyses were conducted to explore distribution, habitat use and selection in a use-availability context, and food habits of these two species. We found almost complete separation of bobcat and gray fox use of transects, as well as indication of partitioning of vegetation cover types and food. We demonstrate an integrated framework of Western and Indigenous sciences that allows the Indigenous researcher to transcend structured academic disciplinary boundaries. Our approach can be modified for partnerships between Tribes, agencies, academics and students for wildlife monitoring in broader geographic regions in various research applications.

Assessment of wild prey of mammalian carnivores in Barda Wildlife Sanctuary, Gujarat, India

The Barda Wildlife Sanctuary (Barda WLS) is a semi-arid ecosystem that plays an important role in the conservation of mammalian carnivores. It is essential to evaluate the population of important wild prey species in Barda, which has conservation implications for mammalian predators and themselves. We assessed the density, biomass, and population structure of wild prey species by surveying road (n = 10) and trail (n = 8) transects using the distance sampling framework method. We used male-to-female sex ratios and the percent contribution of each age class to assess population structure. Mean group size (MGS), median group size (Mdgs), and mean crowding (Mc) were calculated to analyze group size. Of the species studied, Indian peafowl had the highest density (51.61 ± 7.08 individuals/km2), followed by wild pig (10.77 ± 4.59), blue bull (3.50 ± 0.51), Indian hare (3.03 ± 0.73), and spotted deer (0.62 ± 0.04). The male-to-adult female sex ratio was biased towards females, except for Indian peafowl. All species had small group sizes except wild pigs. The results of this study can aid in its development as one of the important protected areas in Gujarat for the conservation of mammalian predators, along with framing conservation strategies for Barda WLS.

Recent trends in populations of Critically Endangered Gyps vultures in India

Summary This paper reports results from the eighth of a series of road transect surveys of Gyps vultures conducted across northern, central, western, and north-eastern India since the early 1990s. Populations of the White-rumped Vulture Gyps bengalensis, Indian Vulture G. indicus, and Slender-billed Vulture G. tenuirostris declined rapidly, beginning in the mid-1990s. The principal cause of the declines was poisoning due to widespread veterinary use of the non-steroidal anti-inflammatory drug (NSAID) diclofenac on cattle. The results of the current survey suggest that, while populations of all three species of vulture remain at a low level with no signs of recovery, they appear to have been approximately stable since veterinary use of diclofenac was banned in the mid-2000s. Population trends in India, where the illegal use of diclofenac and legal use of other toxic NSAIDs continues, are compared with more positive trends in Nepal, where the veterinary use of toxic NSAIDs appears to have been reduced to a low level.

Leading the way – presence of brown bear <i>Ursus arctos</i>, lynx <i>Lynx lynx</i> and grey wolf <i>Canis lupus</i> underlines the integrity and corridor function of the upper Neretva Valley in Bosnia and Herzegovina

Despite its connecting character to the Sutjeska National Park in the North-East, the course of the upper Neretva (Ulog and Borač valley) in Bosnia and Herzegovina (BiH), has to date not been an area of focus for carnivore research. With the aim of contributing to an improved understanding of the present distribution of large and endangered carnivores in this area, a field survey was conducted during the Neretva Science Week 2022. Opportunistic data collection was carried out along a predefined road transect (20 km) and six line transects (13 km) tracked by foot. Additionally, reports of mammal signs for six corresponding research sites along the Neretva were registered. Altogether, at least 15 mammal species could be distinguished. From the identified carnivores, four are listed in Annex II of the Habitats Directive. Furthermore, the signs of lynx presence, in addition to brown bear and grey wolf, highlight the connectivity value of the upper Neretva in its current state. Based on information from local practitioners, the main threats to large carnivores are hunting pressure and a negative perception as competitors. A likely decline in habitat quality and fragmentation, due to the planned hydropower plants expansion and logging activities, exacerbate these threats. Consequently, further systematic monitoring is recommended to assess the possible impact of human driven environmental changes.

Seasonal variation in giraffe population density and abundance in the Tsavo landscape, Kenya

AbstractThe giraffe population is thought to vary seasonally in the Tsavo landscape of Kenya, but little data exists to establish if there indeed exists any variability. This study examined the impact of seasonal variation on the giraffe population in the Tsavo landscape. We conducted road transect counts and found 2683 and 3295 giraffes during the wet and dry seasons, with mean KAI and density of 0.19 ± 0.01 and 1.20 ± 0.435/km2, respectively. The giraffe population did not vary significantly between seasons, age and sex. The parks had more giraffes during the wet season compared to the dry season, while the reverse was true for Rombo and Taita ranches. No giraffes were sighted in South Kitui National Reserve.

The semi-arid ecosystem of Asiatic Lion Landscape in Saurashtra, Gujarat: Population density, biomass and conservation of nine wild prey species.

The present study aimed to assess the population density, structure, and population change of nine wild prey species in the semi-arid landscape of Saurashtra, Gujarat, India. A total of eight sites, representing a gradient from highly protected woodlands and grasslands to unreserved grasslands, were selected for sampling. We employed the road transect methodology under a distance sampling framework to achieve our objectives. We evaluated the realized growth rate of the Gir ungulate population through linear regression analysis. Our findings revealed that deer species exhibited higher density and biomass in woodlands compared to grasslands and coastal forests. On the other hand, antelopes showed higher density and biomass in grasslands and coastal forests compared to woodlands. The density gradient of wild prey species was influenced by various factors, including habitat structure, social organization, grouping tendencies, and topography. Over the last four decades, the population of wild prey species in Gir showed minimal changes. Our study provides a comprehensive understanding of wild prey species' density and biomass patterns at the landscape level. The inclusion of findings from ecologically significant and unique areas, such as coastal forests, further enhances the importance of this study. The implications of this study extend beyond the conservation of wild prey species alone; they also contribute to the conservation of the large carnivore guild in the Saurashtra landscape.

Assessing the accuracy of population estimation methods for vulture populations: a case study from the Mudumalai Tiger Reserve, Tamil Nadu, India

Two resident and two local migratory vulture species are reported in the Mudumalai Tiger Reserve of the Nilgiri Biosphere Reserve. The early population estimates from the region are either scanty or crude. Vulture population estimation was performed using three different methods based on their breeding seasons and regional movements between 2019 and 2021. Road transect counts, nest counts, and carcass monitoring counts were used for population assessments. The road transect survey and nest site counting during the breeding season were conducted in all three years, while carcass monitoring was done in 2019 – 2020. For population estimation, three nest site colony counts were conducted for the resident Gyps bengalensis and for Gyps indicus. The other two methods, carcass monitoring and the road transect survey, were used for all four focal vulture species of the Mudumalai Tiger Reserve – Gyps bengalensis, Gyps indicus, Neophron percnopterus and Sarcogyps calvus. Significant variation in vulture population count was observed with different assessment methods.

Advancing fence datasets: Comparing approaches to map fence locations and specifications in southwest Montana

Fencing is a major anthropogenic feature affecting wildlife distributions and movements, but its impacts are difficult to quantify due to a widespread lack of spatial data. We created a fence model and compared outputs to a fence mapping approach using satellite imagery in two counties in southwest Montana, USA to advance fence data development for use in research and management. The model incorporated road, land cover, ownership, and grazing boundary spatial layers to predict fence locations. We validated the model using data collected on randomized road transects (n = 330). The model predicted ~34,700 km of fences with a mean fence density of 0.93 km/km2 and a maximum density of 14.9 km/km2. We also digitized fences using Google Earth Pro in a random subset of our study area in survey townships (n = 50). The Google Earth approach showed greater agreement (K = 0.76) with known samples than the fence model (K = 0.56) yet was unable to map fences in forests and was significantly more time intensive. We also compared fence attributes by land ownership and land cover variables to assess factors that may influence fence specifications (e.g., wire heights) and types (e.g., number of barbed wires). Private land fences had bottom wires that were closer to the ground and top wires higher from the ground when compared to fences on public lands, with sample means at ~22 cm and ~26 cm, and ~115 cm and ~111 cm, respectively. Both bottom wire means were well below recommended heights for ungulates navigating underneath fencing (≥ 46 cm), while top wire means were closer to the 107 cm maximum fence height recommendation. We found that both fence type and land ownership were correlated (χ2 = 45.52, df = 5, p = 0.001) as well as fence type and land cover type (χ2 = 140.73, df = 15, p = 0.001). We provide tools for estimating fence locations, and our novel fence type assessment demonstrates an opportunity for updated policy to encourage the adoption of “wildlife-friendlier” fencing standards to facilitate wildlife movement in the western U.S. while supporting rural livelihoods.

Evaluating the prevalence and spatial distribution of giraffes injured by non‐target poaching

AbstractIllegal harvest (poaching) is a geographically widespread threat to animal populations. Wire snares are a common poaching technique used in the Global South and are indiscriminate with respect to species, age, and sex of individual animals that they capture. When caught, relatively large mammals frequently break free from the snares, suffering injuries in the process. The prevalence of snaring injuries as well as the ecological and conservation implications of such patterns have not been widely investigated for many animal populations. We evaluated the prevalence and spatial distribution of giraffes (Giraffa camelopardalis) with snaring injuries in Murchison Falls National Park, Uganda, a system experiencing high rates of wire snare poaching. We conducted photographic spatial encounter surveys along five fixed road transects. We photographed detected giraffes, recorded whether a snaring injury was present, and identified individuals via autonomous image processing of pelage patterns. We fitted a spatial capture‐recapture (SCR) model to the encounter history data to estimate abundance and predict the spatial distribution of injured giraffes. We detected 1306 (sub) adult giraffes from the surveys and predicted 1939 (±80) via the SCR model. We encountered 26 giraffes with snaring injuries, corresponding to a population‐level snaring rate of 1.4%. Individuals with higher movement scales were more at risk of being snared. Though not fatal across the three‐month duration of this study, the injuries likely lead to secondary infections, disability, and potentially death in the long term. We explore the implications of bearing snaring injuries for ecology, behavior, and conservation of affected species.

Population dynamics of the Manyara monkey (Cercopithecus mitis manyaraensis) and vervet monkey (Chlorocebus pygerythrus) in Lake Manyara National Park, Tanzania.

Estimating population densities and their trends over time is essential for understanding primate ecology and for guiding conservation efforts. From 2011 through to 2019, we counted two guenon species during seasonal road transect surveys in Lake Manyara National Park: the Tanzania-endemic Manyara monkey Cercopithecus mitis manyaraensis (International Union for Conservation of Nature and Natural Resources, IUCN, Red List category of "endangered") and the vervet monkey Chlorocebus pygerythrus (Red List category of "least concern"). To account for imperfect detectability, we analysed the data in a line distance sampling framework, fitted species-specific detection functions, and subsequently estimated seasonal densities. To test for seasonal differences and yearly trends in the species-specific density estimates, we fitted generalized additive models. Seasonal point density estimates fluctuated considerably during the 9years (2011-2019) of our study, ranging from 3 to 29 individuals km for Manyara monkeys and from 19 to 83 individuals km for vervet monkeys. Densities of both taxa did not differ seasonally, and we did not detect marked directional population trends. Our study illustrates the utility and limitations of line distance sampling for long-term primate monitoring. Beyond informing primate ecology and management, our results highlight the conservation importance of Lake Manyara National Park for primate conservation.

Assessment of an inexpensive trap design and survey method for vespine wasps (Hymenoptera, Vespidae, Vespinae)

The introduction of the predatory Giant Asian Hornet, Vespa mandarinia Smith, to North America in 2019 has motivated efforts to create early detection systems for this and other non-native social wasp species (Hymenoptera, Vespidae). Various trap and bait combinations have been used for this purpose, most of which require assembly and materials that are costly, reducing their usefulness in large-scale survey systems. This study tests an inexpensive and efficient trapping technique for detecting or surveying vespine wasps. Traps were made from reused plastic bottles containing a brown sugar and water bait. They were deployed at heights ranging from 0–6 m above ground in several configurations. Captures for traps suspended 1 m or greater above ground were, on average, nine times higher than the catch of ground-level traps. A rapid trap deployment method for large geographic areas was created, which captured seven different vespine wasp species along a 395 km east-west road transect from mountains to coastal plain in the Mid-Atlantic region of the United States. The trapping design and survey methodology described below is inexpensive and fast and could be used by land managers or citizen scientists to detect V. mandarinia, other exotic vespine, or conducted on a large-scale vespine diversity survey.

Road-based line distance surveys overestimate densities of olive baboons.

Estimating population density and population dynamics is essential for understanding primate ecology and relies on robust methods. While distance sampling theory provides a robust framework for estimating animal abundance, implementing a constrained, non-systematic transect design could bias density estimates. Here, we assessed potential bias associated with line distance sampling surveys along roads based on a case study with olive baboons (Papio anubis) in Lake Manyara National Park (Tanzania). This was achieved by comparing density estimates of olive baboons derived from road transect surveys with density estimates derived from estimating the maximum number of social groups (via sleeping site counts) and multiplying this metric with the estimated average size of social groups. From 2011 to 2019, we counted olive baboons along road transects, estimated survey-specific densities in a distance sampling framework, and assessed temporal population trends. Based on the fitted half-normal detection function, the mean density was 132.5 baboons km-2 (95% CI: 110.4–159.2), however, detection models did not fit well due to heaping of sightings on and near the transects. Density estimates were associated with relatively wide confidence intervals that were mostly caused by encounter rate variance. Based on a generalized additive model, baboon densities were greater during the rainy seasons compared to the dry seasons but did not show marked annual trends. Compared to estimates derived from the alternative method (sleeping site survey), distance sampling along road transects overestimated the abundance of baboons more than threefold. Possibly, this overestimation was caused by the preferred use of roads by baboons. While being a frequently used technique (due to its relative ease of implementation compared to spatially randomized survey techniques), inferring population density of baboons (and possibly other species) based on road transects should be treated with caution. Beyond these methodological concerns and considering only the most conservative estimates, baboon densities in LMNP are among the highest across their geographic distribution range.

The Potential Role of Drove Roads as Connecting Corridors for Birds between Natura 2000 Sites

Ecological connectivity among protected Natura 2000 sites is a priority for conservation in Europe due to the increasing pressure on biodiversity from human activities and climate change. Drove roads, the traditional paths used to move livestock through the territory, have been proposed as potential ecological corridors due to their large extent, continuous nature and centennial protection from ploughing and urbanization, which allows the persistence of some tree cover and natural habitats in them. Bird communities were sampled during the reproductive season along 19 drove road transects in agrarian landscapes between Natura 2000 sites, all of them around the conurbation of Madrid (Madrid Region, Spain). Bird community nestedness was assessed by NODF computation followed by significance estimation by aleatorization, and factors explaining species richness and bird abundance were analyzed through General Linear Models fitted with environmental variables measured on official vegetation maps and orthophotos. Bird communities in drove roads were significantly nested, showing high predictability in the order of species loss from better preserved sites to those under stronger environmental pressures. Accordingly, Poisson regression showed bird richness to decrease strongly with distance from the closest Natura 2000 site and to increase with forest cover at the landscape and at the drove road scales. Bird abundance increased strongly with distance from urban areas and motorways, and it was slightly higher in areas with more forest cover and in transects with less bare ground. These results, and the higher relevance detected for landscape scale variables (500 m around transects) than for those at the drove road (50 m) scale, show that (i) they can only play a secondary role as habitat for nesting birds but (ii) they may add to the Green Infrastructure strategy as facilitators or stepping stones for bird communities if the surrounding landscape is favorable for them.

Prevalence and histopathological characterization of Masai Giraffe (Giraffa camelopardalis tippelskirchi) skin disease in Tarangire-Manyara ecosystem, Northern Tanzania

Background: Masai Giraffes have declined dramatically in recent decades due to loss of habitat and illegal hunting. Hence, it is critically important that the epidemiology and etiology of so-called giraffe skin disease (GSD) is understood well. Aim: To assess the prevalence and histopathological characteristics of GSD in the Tarangire-Manyara Ecosystem (TME), northern Tanzania. Methods: The study used road transects to gather field information on GSD. Eighty-four giraffes were sighted by systematic random sampling in the six study sites. Examination of giraffes involved body distribution of lesions, severity of the lesions and whether they were associated with age and sex of the affected giraffes. Five giraffes with GSD were immobilized for tissue collection and histopathological analysis. Results: Prevalence among adults was 79%. Affected animals typically had 1-5 lesions which were mostly moderate and were predominantly observed on the forelegs. GSD positivity rate was higher among females versus males, whereas males had a higher rate of severe lesions and generally had more lesions than females. Calves showed no lesions. All tissue sections from five affected giraffes showed the presence of large quantities of fungal elements (hyphae and spores) that involved hair shafts and sub-cutaneous tissue after staining with Grocott Methenamine Silver as special fungal staining technique. Conclusions: Our findings suggest the involvement of fungal infection in GSD pathogenesis. Clinical relevance: We recommend further characterization of the lesions using modern molecular techniques and culture to identify primary and secondary or opportunistic etiologies, and the order in which the pathogens occur in the lesions.

Roadkill islands: Carnivore extinction shifts seasonal use of roadside carrion by generalist avian scavenger.

Global road networks facilitate habitat modification and are integral to human expansion. Many animals, particularly scavengers, use roads as they provide a reliable source of food, such as carrion left after vehicle collisions. Tasmania is often cited as the 'roadkill capital of Australia', with the isolated offshore islands in the Bass Strait experiencing similar, if not higher, levels of roadkill. However, native mammalian predators on the islands are extirpated, meaning the remaining scavengers are likely to experience lower interference competition. In this study, we used a naturally occurring experiment to examine how the loss of mammalian carnivores within a community impacts roadside foraging behaviour by avian scavengers. We monitored the locations of roadkill and forest ravens Corvus tasmanicus, an abundant scavenger species, on eight road transects across the Tasmanian mainland (high scavenging competition) and the Bass Strait islands (low scavenging competition). We represented raven observations as one-dimensional point patterns, using hierarchical Bayesian models to investigate the dependence of raven spatial intensity on habitat, season, distance to roadkill and route location. We found that roadkill carcasses were a strong predictor of raven presence along road networks. The effect of roadkill was amplified on roads on the Bass Strait islands, where roadside carrion was a predictor of raven presence across the entire year. In contrast, ravens were more often associated with roadkill on Tasmanian mainland roads in the autumn, when other resources were low. This suggests that in the absence of competing mammalian scavengers, ravens choose to feed on roadside carrion throughout the year, even in seasons when other resources are available. This lack of competition could be disproportionately benefiting forest ravens, leading to augmented raven populations and changes to the vertebrate community structure. Our study provides evidence that scavengers modify their behaviour in response to reduced scavenger species diversity, potentially triggering trophic shifts and highlighting the importance of conserving or reintroducing carnivores within ecosystems.

Population status and feeding behavior of black kite (Milvus migrans) in Dhaka city, Bangladesh

The status and feeding behavior of black kite (Milvus migrans) in Dhaka city were studied from July 2015 to June 2017. Road transects and morning roost-count method were used for population estimation and distribution, whereas focal sampling method was used to study the feeding and foraging behavior. Based on roosting and foraging areas, five transects were selected for population estimation. Moreover, six different feeding areas were selected for identifying various types of consumed food and assessing the feeding behavior of black kite. The black kite population was estimated at (1296±5.87) in Dhaka city. The population density was estimated at 21.8/km2. Among selected five different transects, the recorded population ranged from 108.12±6.70, 8.34%) at S-3 (Mirpur to Ramna Park) to 805±11.88, 62.11% of individuals at S-5 (Gulistan to Demra). The present study revealed that black kites were distributed throughout the study area and the distribution was influenced by availability of food, water and roosting place. Based on the annual records, the highest population (1510±6.92) was found in 2016. Majority of black kites fed on offal and insects in study area. In garbage dumps, the highest rate of feeding was recorded in afternoon followed by in morning and lowest in the noon. Whereas in non-garbage feeding areas, the highest rate was recorded in the morning followed by in the afternoon and lowest in the noon. Among four different foraging strategies, food collection by kites standing on the ground and intraspecific cleptoparasitism was never observed during study period while interspecific cleptoparasitism (against crows) was the highest number (193.67±2.77, 68.43%).
 Jahangirnagar University J. Biol. Sci. 9(1 & 2): 35-48, 2020 (June & December)

Vocal behavior of the Mountain Hawk-Eagle Nisaetus nipalensis in Taiwan

The Mountain Hawk-Eagles (Nisaetus nipalensis) is a large raptor native to Asia. Despite the wide distribution of this species, their vocalizations have been described only occasionally, and no studies have provided detailed outcomes for other researchers to follow. This study aimed to obtain systematic and comprehensive results on the vocalizations of the Mountain Hawk-Eagle and a preliminary understanding of its vocal behavior in terms of temporal changes. This study performed a road transect survey along two forestry roads between January 2006 and December 2008 in Taitung County. Two nests were found and observed upstream of the Dazhu and Fangshan streams during the breeding season in 2007 and 2010, respectively. All vocalizations, vocal behavior, and behavior context were recorded. Mountain Hawk-Eagles were discovered to produce at least seven types of vocalization depending on context and structure. The flying call was recorded throughout the year and was made by both sexes. Some vocalizations were recorded only during the breeding season or could only be identified around the nest area; for example, the female begging call, juvenile begging call, and alarm call. From the road transect survey and observation of nests during breeding seasons, we discovered temporal variation in the call rate of the Mountain Hawk-Eagle. The findings and recordings made in this study provide insight into the vocal behavior of the Mountain Hawk-Eagle, but further investigations are needed.

Ostrich population densities and temporal dynamics in coupled social-ecological systems: Suitable indicators for the ecological effectiveness of protected areas?

Assessing the ecological effectiveness of protected areas is a high priority in conservation biology and requires suitable indicators. Instead of using multiple species, single species can potentially be used as indicators to assess if conservation efforts are effective in maintaining species over time. Here, we assessed the suitability of ostrich (Struthio camelus massaicus) population densities and trends over time as indicators for the ecological effectiveness of four study areas (two national parks, a pastoral area, and a game-controlled area with manifold human impacts) in the Tarangire-Manyara ecosystem of northern Tanzania. Based on road transect surveys from 2011 to 2019, we estimated area- and season-specific population densities in a distance sampling framework and estimated temporal changes using generalized linear mixed models. Ostrich population densities and population trends over time were not associated with formal protection status. Ostriches in one national park occurred at highest densities and were constant over time, while densities were low in another national park and apparently declined over time. Ostriches in the pastoral area had the second-highest mean population density, while remaining constant over time. The study area with the highest human impact had lowest ostrich densities and a seemingly declining trend over time. Ostrich densities were positively correlated with time-matched population density estimates of nine out of ten ungulate species in the same study areas, suggesting that ostrich population densities broadly reflect those of large savanna mammals in this ecosystem. However, site-specific ostrich population trends over time were not closely correlated with trends of common large mammal species. Therefore, ostrich population densities appear as suitable management indicators to assess the broad ecological effectiveness of protected areas. However, ostrich population trajectories do not appear suitable as indicator surrogate to monitor trends of mammal populations over time.