Long-term Population Monitoring Research Articles

Immigration allows population persistence and maintains genetic diversity despite an attempted experimental extinction.

Widespread fragmentation and degradation of habitats make organisms increasingly vulnerable to declines in population size. Immigration is a key process potentially affecting the rescue and persistence of populations in the face of such pressures. Field research addressing severe demographic declines in the context of immigration among interconnected local populations is limited owing to difficulties in detecting such demographic events and the need for long-term monitoring of populations. In a 17-subpopulation metapopulation of the butterfly, Parnassius smintheus, all adults observed in two adjacent patches were removed over eight consecutive generations. Despite this severe and long-term reduction in survival and reproduction, the targeted populations did not go extinct. Here, we use genetic data to assess the role of immigration versus in situ reproduction in allowing the persistence of these populations. We genotyped 471 samples collected from the targeted populations throughout the removal experiment at 152 single nucleotide polymorphisms. We found no reduction in the genetic diversity of the targeted populations over time, but a decrease in the number of loci in Hardy-Weinberg equilibrium, consistent with a high level of immigration from multiple surrounding populations. Our results highlight the role of connectivity and movement in making metapopulations resilient to even severe and protracted localized population reductions.

The establishment of a collaborative surveillance program with indigenous hunters to characterize primate health in Southern Guyana.

The consumption of primates is integral to the traditional subsistence strategies of many Indigenous communities throughout Amazonia. Understanding the overall health of primates harvested for food in the region is critical to Indigenous food security and thus, these communities are highly invested in long-term primate population health. Here, we describe the establishment of a surveillance comanagement program among the Waiwai, an Indigenous community in the Konashen Amerindian Protected Area (KAPA). To assess primate health in the KAPA, hunters performed field necropsies on primates harvested for food and tissues collected from these individuals were analyzed using histopathology. From 2015 to 2019, hunters conducted 127 necropsies across seven species of primates. Of this sample, 82 primates (between 2015 and 2017) were submitted for histopathological screening. Our histopathology data revealed that KAPA primates had little evidence of underlying disease. Of the tissue abnormalities observed, the majority were either due to diet (e.g., hepatocellular pigment), degenerative changes resulting from aging (e.g., interstitial nephritis, myocyte lipofusion), or nonspecific responses to antigenic stimulation (renal and splenic lymphoid hyperplasia). In our sample, 7.32% of individuals had abnormalities that were consistent with a viral etiology, including myocarditis and hepatitis. Internal parasites were observed in 53.66% of individuals and is consistent with what would be expected from a free-ranging primate population. This study represents the importance of baseline data for long-term monitoring of primate populations hunted for food. More broadly, this research begins to close a critical gap in zoonotic disease risk related to primate harvesting in Amazonia, while also demonstrating the benefits of partnering with Indigenous hunters and leveraging hunting practices in disease surveillance and primate population health assessment.

Bird communities in a selectively logged tropical montane forest are dominated by small, low-elevation species

Tropical montane forests are critical centres of terrestrial biodiversity and endemism, and face a range of threats, including selective logging and climate change. However, few studies have explored the joint influence of these threats, particularly in tropical mountains, despite how crucial it is to understand the cumulative impact of forest loss and climate change on biodiversity. We used mist-netting and bird ringing data from a long-term (10-year) community and population monitoring program to examine how the composition of the mid-elevation Eastern Himalayan understorey bird community changed in the mid-elevation primary and logged forest. Because logged forest is warmer than primary forest, we hypothesised that the bird community would shift towards lower elevation species, with a faster transition in logged forest. Further, because logged forest has lower arthropod abundance, we hypothesised that the primary forest community would have larger species than the logged forest community. Our study shows that the bird community in the logged forest shifted towards lower-elevation species than in the primary forest (although this was not statistically significant). Moreover, we found that smaller species were better able to colonise warmer logged forest, whereas larger species reached higher densities in primary forest. These trends are likely to be driven by climate change causing upslope range shifts and logged forest selecting for species that are likely to tolerate the consequently altered abiotic (higher temperatures) and biotic (lower resources) environment. These findings have significant implications for understanding the impacts of forest loss and climate change on biodiversity, particularly in tropical montane forests.

Variation in avian responses to rice intensification in the central plains of Thailand guides conservation opportunities

Multiple studies indicate that grassland and farmland birds are declining in temperate zones, but few have been conducted in the tropics. Here we examined effects of rice intensification on landbird communities and estimated habitat-specific densities of eight songbird species of national and/or global conservation concern in the central plains of Thailand where rice is intensively cultivated often with triple annual rice crops. From 1410 point-counts, we observed 236 species including 26 landbirds of conservation concern. The landbird species community was significantly associated with different intensification levels, with eleven species of concern primarily found in single-cropped fields. Three of the eight focal species (i.e., Horsfield's bushlark Mirafra javanica, Oriental skylark Alauda gulgula, and striated grassbird Megalurus palustris) had lower densities with increased intensification. Natural habitat features (i.e., field margins, reedbeds, and scattered trees) positively influenced densities of all species, even those unaffected by intensification. Densities of Manchurian reed warbler Acrocephalus tangorum, streaked weaver Ploceus manyar, and Asian golden weaver P. hypoxanthus were positively correlated with increases in field margins and reedbeds. Plain-backed sparrow Passer flaveolus density was positively related to presence of scattered trees. Long-tailed shrike Lanius schach density appeared to have a positive correlation with field margins and was significantly negatively correlated with urbanization. Our findings underscore the necessity of adopting policies that encourage wildlife-friendly land management in Southeast Asia, reducing intensification of agricultural landscapes that support species of conservation concern and preserving natural habitat features. Long-term population monitoring is also needed to better understand trends and judge management efficacy.

Camera-based automated monitoring of flying insects (Camfi). I. Field and computational methods.

The ability to measure flying insect activity and abundance is important for ecologists, conservationists and agronomists alike. However, existing methods are laborious and produce data with low temporal resolution (e.g. trapping and direct observation), or are expensive, technically complex, and require vehicle access to field sites (e.g. radar and lidar entomology). We propose a method called "Camfi" for long-term non-invasive population monitoring and high-throughput behavioural observation of low-flying insects using images and videos obtained from wildlife cameras, which are inexpensive and simple to operate. To facilitate very large monitoring programs, we have developed and implemented a tool for automatic detection and annotation of flying insect targets in still images or video clips based on the popular Mask R-CNN framework. This tool can be trained to detect and annotate insects in a few hours, taking advantage of transfer learning. Our method will prove invaluable for ongoing efforts to understand the behaviour and ecology of declining insect populations and could also be applied to agronomy. The method is particularly suited to studies of low-flying insects in remote areas, and is suitable for very large-scale monitoring programs, or programs with relatively low budgets.

Camera-based automated monitoring of flying insects in the wild (Camfi). II. flight behaviour and long-term population monitoring of migratory Bogong moths in Alpine Australia.

The Bogong moth Agrotis infusa is well known for its remarkable annual round-trip migration from its breeding grounds across eastern and southern Australia to its aestivation sites in the Australian Alps, to which it provides an important annual influx of nutrients. Over recent years, we have benefited from a growing understanding of the navigational abilities of the Bogong moth. Meanwhile, the population of Bogong moths has been shrinking. Recently, the ecologically and culturally important Bogong moth was listed as endangered by the IUCN Red List, and the establishment of a program for long-term monitoring of its population has been identified as critical for its conservation. Here, we present the results of two years of monitoring of the Bogong moth population in the Australian Alps using recently developed methods for automated wildlife-camera monitoring of flying insects, named Camfi. While in the Alps, some moths emerge from the caves in the evening to undertake seemingly random flights, filling the air with densities in the dozens per cubic metre. The purpose of these flights is unknown, but they may serve an important role in Bogong moth navigation. We found that these evening flights occur throughout summer and are modulated by daily weather factors. We present a simple heuristic model of the arrival to and departure from aestivation sites by Bogong moths, and confirm results obtained from fox-scat surveys which found that aestivating Bogong moths occupy higher elevations as the summer progresses. Moreover, by placing cameras along two elevational transects below the summit of Mt. Kosciuszko, we found that evening flights were not random, but were systematically oriented in directions relative to the azimuth of the summit of the mountain. Finally, we present the first recorded observations of the impact of bushfire smoke on aestivating Bogong moths - a dramatic reduction in the size of a cluster of aestivating Bogong moths during the fire, and evidence of a large departure from the fire-affected area the day after the fire. Our results highlight the challenges of monitoring Bogong moths in the wild and support the continued use of automated camera-based methods for that purpose.

Snaring devastates terrestrial ungulates whilst sparing arboreal primates in Cambodia's Eastern Plains Landscape

Snaring poses a significant threat to terrestrial animals in many parts of Southeast Asia. However, long-term population monitoring data to determine the impact of snaring on wildlife populations is limited. We used distance sampling to estimate wildlife densities and population trends and data collected from ranger patrols to assess snare numbers across two protected areas in Cambodia's Eastern Plains Landscape. We found that the populations of three ungulate species, including the globally endangered banteng (Bos javanicus), steeply declined as snare numbers appeared to increase. In the same time period, the populations of two globally threatened arboreal primates remained similar or increased. Our findings indicate that snaring likely impacts ground-dwelling ungulates whilst sparing arboreal primates. Current ungulate densities are at critically low levels with several species at the brink of extirpation in our study area. We recommend urgent and comprehensive conservation actions to restrict snaring and prevent irreversible wildlife population collapses in this landscape and across the broader region.

SensorDrop: A system to remotely detach individual sensors from wildlife tracking collars.

The growing diversity of animal-borne sensor types is revolutionizing our understanding of wildlife biology. For example, researcher-developed sensors, such as audio and video loggers, are being increasingly attached to wildlife tracking collars to provide insights into a range of topics from species interactions to physiology. However, such devices are often prohibitively power-intensive, relative to conventional wildlife collar sensors, and their retrieval without compromising long-term data collection and animal welfare remains a challenge. We present an open-source system (SensorDrop) for remotely detaching individual sensors from wildlife collars. SensorDrop facilitates the retrieval of power-intensive sensors while leaving non-resource-intensive sensors intact on animals. SensorDrop systems can be made using commercially available components and are a fraction of the cost of other timed drop-off devices that detach full wildlife tracking collars. From 2021 to 2022, eight SensorDrop units were successfully deployed on free-ranging African wild dog packs in the Okavango Delta as part of audio-accelerometer sensor bundles attached to wildlife collars. All SensorDrop units detached after 2-3 weeks and facilitated the collection of audio and accelerometer data while leaving wildlife GPS collars intact to continue collecting locational data (>1 year), critical for long-term conservation population monitoring in the region. SensorDrop offers a low-cost method to remotely detach and retrieve individual sensors from wildlife collars. By selectively detaching battery-depleted sensors, SensorDrop maximizes the amount of data collected per wildlife collar deployment and mitigates ethical concerns on animal rehandling. SensorDrop adds to the growing body of open-source animal-borne technologies being utilized by wildlife researchers to innovate and expand upon data collection practices and supports the continued ethical use of novel technologies within wildlife studies.

BREEDING ECOLOGY, NESTING HABITAT AND THREATS TO A BLACK-AND-CHESTNUT EAGLE SPIZAETUS ISIDORI POPULATION IN THE MONTANE FORESTS OF CENTRAL PERU

The Black-and-chestnut Eagle Spizaetus isidori is an endangered and little-known top predator of South American montane forests. To better understand the breeding ecology and threats of this eagle, we studied several pairs between 2017 and 2022 in the central Andes of Peru. We recorded 62 adults, one immature, and 36 juveniles in 36 territories. These territories were in mountainous areas (altitudinal range 690–3,810 m a.s.l.), widely covered by montane forests (43.8–99.7% cover), and secondarily by open land (0.3–56.2% cover), far from urban settlements (1.3–27.1 km). Nesting sites (N = 15) were at medium altitudes (1,330–2,330 m a.s.l.) in steep hillsides or ravines (15–55°), having no preferential cardinal orientation, and relatively close to permanent water courses (20–800 m), open areas (30–930 m) and sites with human activity (120–2,200 m). Nests (N = 15) were placed at the top of tall (28–40 m) and thick-stemmed (DBH range 0.53–1.52 m) emergent trees of nine genera, with Ficus and Juglans being the most used. Incubation and brood-rearing occurred during the dry season (Mar–Nov). The wooded slopes where the eagles nested are being replaced by crops and livestock pastures, causing an estimated loss of 218.2 km2 of forest cover in our study area (5,056 km2) during the last 20 years. We detected human persecution in 55.5% of the territories, resulting in 26 juveniles, four adults, two immatures, and nine unaged eagles killed. Preventing the local extinctions of these eagles will require long-term population monitoring, improving knowledge of its ecology, mitigation of human-eagle conflict, development of education programs, and strengthening of land use inspection.

No Evidence of Long-Term Effects on Physiological Stress or Innate Immune Functioning in Northern Map Turtles a Decade After a Freshwater Oil Spill

Environmental perturbations such as chemical spills often have immediate and obvious effects on the health of ecosystems and individual organisms. However, the long-term effects of such perturbations are less evident and often less well-understood. In July 2010, a ruptured pipeline spilled diluted bitumen into the Kalamazoo River in Michigan, USA, ultimately oiling 56 km of the river channel. During spill cleanup operations, the most common vertebrate species rescued from the oiled river channel was the Northern Map Turtle (Graptemys geographica), of which over 2000 individuals were captured, cleaned of oil, and released. We returned to areas along the 2010 spill gradient to determine whether turtles from locations that had experienced different magnitudes of oiling in 2010 differed in baseline stress levels or immune functioning in 2020, which was 10 yr after the oil spill. In 2020, we collected blood samples from 100 individual Northern Map Turtles along the 2010 spill gradient and subsequently quantified the heterophil:lymphocyte ratio, bactericidal capacity, and natural antibody agglutination. We found no correlation between turtles' 2020 capture locations relative to the origin of the 2010 oil spill and either mean stress level (heterophil:lymphocyte ratio) or immune functioning (bactericidal capacity and natural antibody agglutination ability). Thus, we found no evidence that Northern Map Turtles sampled along a gradient of oil exposure resulting from the 2010 Kalamazoo River oil spill experienced long-term effects on physiological stress levels or immune functioning. Importantly, our sampling did not include any individuals that may have died during 2010–2020 from poor health after the oil spill and therefore is biased toward healthy turtles remaining in the population. Interestingly, we found that a subset of turtles known to have been oiled in 2010 actually had higher natural antibody titers than turtles sampled from a control site that presumably had never been exposed to oil. We cannot exclude the possibility of other long-term effects of the oil spill on the Map Turtle population, such as decreased reproductive output. We recommend that long-term monitoring of populations and ecosystems be included in spill mitigation plans to track the recovery of populations and ecosystems over time and to document any effects that may become evident only years after the spill event.

Non-destructive insect metabarcoding as a surveillance tool for the Australian grains industry: a first trial for the iMapPESTS smart trap

Surveillance and long-term monitoring of insect pest populations are of paramount importance to limit dispersal and inform pest management. Molecular methods have been employed in diagnostics, surveillance and monitoring for the past few decades, often paired with more traditional techniques relying on morphological examinations. Within this context, the ‘iMapPESTS: Sentinel Surveillance for Agriculture’ project was conceptualised to enhance on-farm pest management decision-making via development and deployment of smart traps, able to collect insects, as well as recording associated environmental data. Here, we compared an iMapPESTS ‘Sentinel’ smart trap to an alternative suction trap over a 10-week period. We used a non-destructive insect metabarcoding approach complemented by insect morphological diagnostics to assess and compare aphid species presence and diversity across trap samples and time. Furthermore, we paired this with environmental data recorded throughout the sampling period. This methodology recorded a total of 497 different taxa from 70 traps over a 10-week period in the grain-growing region in western Victoria. This included not only the 14 aphid target species, but an additional 12 aphid species, including a new record for Victoria. Ultimately, with more than 450 bycatch species detected, this highlighted the value of insect metabarcoding, not only for pest surveillance, but also at a broader ecosystem level, with potential applications in integrated pest management and biocontrol.

Многолетняя динамика численности крупных ищных птиц на ключевой орнитологической территории «Камско-Бакалдинские болота» (Нижегородская область, Россия)

Identification of breeding territories and long-term population monitoring has been carried out in the Important Bird Areas (IBA) with a global importance “Kamsko-Bakaldinskiye marshes” since 1980. Five large bird species were studied here: Osprey (Pandion haliaetus), Short-Toed Eagle (Circaetus gallicus), Greater Spotted Eagle (Aquila [Clanga] clanga), Golden Eagle (Aquila chrysaetos), White-Tailed Eagle (Haliaeetus albicilla). In this report we will summarize the results. IBA covers the northern (Zavolzhsky) part of the Lyskovsky and Vorotynsky districts of the Nizhny Novgorod region, as well as the adjacent areas of Borsky, Semenovsky, and Voskresensky districts. Its total area is 3156.0 km2. The largest massif of upland, transitional, and lowland bogs in the Volga River basin is preserved here in its natural state. A significant part of IBA area (2265 km2) is listed as Ramsar wetland of international importance. Kamsko-Bakaldinskiye marshes has undergone significant transformation over the past 50 years. Until the 1980s, intensive logging was carried out here with an excess areas were organized by 1994, covering 54% of IBA area and leading to a decrease in logging volumes. In the 1980s drainage and peat extraction amounted to 1% of an area. Disastrous fires of 1972 and 2010 spread through about 50% of an area. The number of rare raptor species was positively influenced by the implementation of a unique project to install 62 nesting platforms in 1998–2014. Multidirectional vectors – the destruction of habitats and their conservation, combined with compensatory biotechnical measures, superimposed on the general population trends of large raptors in the center of the European part of Russia. As a result, the population dynamics of different species in Kamsko-Bakaldinskiye marshes differs significantly. The population dynamic for four out of five studied species shows a clear positive trend. Thus, the number of Osprey and White-Tailed Eagle has increased by three and six times, respectively. A project that included nesting platform installation had a significant impact on Osprey population. White-Tailed Eagle depended on it to a lesser extent, however, throughout an entire observation period, there was a general positive trend in the abundance of the species in the European part of Russia. The negative impact of catastrophic fires in 2010 on Osprey and White-Tailed Eagle was insignificant. Abundance of Short-Toed Eagle and Greater Spotted Eagle in 2000–2014 wasseverely underestimated. After 2014, additional data were collected, which allowed us to determine the abundance and distribution of these species in studied area, as well as to identify a positive population trend. In 2000–2014, actual Short-Toed Eagle abundance was twice as high as estimates made in the period. Subsequently, a favorable factor for Short-Toed Eagle was the large burnt area left by fires, which the birds used as new hunting grounds. A twofold increase in Short-Toed Eagle population happened in 2011–2023. The difference in estimates of Greater Spotted Eagle abundance in 2014 and 2018 is mainly due to the results of additional research efforts. Breeding territories have been identified in previously poorly studied floodplain habitats. In addition, the number of Greater Spotted Eagle increased slightly after the fires of 2010 destroyed most of its breeding territories in Kamsko-Bakaldinskiye marshes. The number of Golden Eagle significantly increased in 2000–2010 due to the use of nesting platforms. Then it began to decline due to the long-term depression in Mountain Hare and Grouse populations, as well as catastrophic fires that affected most of breeding territories. Thus, Golden Eagle turned out to be the most vulnerable to pyrogenic changes in their habitat. The number of the species has fallen to the lowest point, almost reaching level of the 1980s. Species’ breeding territories are only preserved in areas unaffected by fires. Golden Eagle’s population decline has had a positive impact on populations of other large raptor species, especially noticeable for Greater Spotted Eagle. The emergence of its breeding territories was noted where Golden Eagle’s breeding territories were lost due to fires. Kamsko-Bakaldinskiye Marshes currently remains the most important refugium for rare large raptor species in Nizhny Novgorod Region, where it is advisable to expand and strengthen protected areas and restore permanent implementation of biotechnical projects.

Long-term monitoring of Aloidendron dichotomum populations: Does tracking individuals make a difference to general demographic findings?

Long-term monitoring of Aloidendron dichotomum populations: Does tracking individuals make a difference to general demographic findings?

An integrated approach for assessing the survival of discarded sandbar sharks, Carcharhinus plumbeus, captured in scientific longlines

Context The sandbar shark (Carcharhinus plumbeus) has a global distribution and is caught by commercial fishers and recreational anglers. Aims To assess the stress physiology, release condition, and post-release survival of sandbar sharks caught in longline surveys conducted in Western Australia. Methods Post-release survival of sandbar sharks caught in longlining surveys was assessed using an integrated approach that combined the use of hook-timers, qualitative release conditions, satellite-tagging, and blood physiology. Key results Of 57 individuals examined, there was 100% post-capture survival after a maximum of 4 h on the hook. Most of these animals (88%) displayed a strong release condition, exhibiting minimal behavioural impairment. All 13 satellite-tagged individuals survived 30 days post-capture. Sharks dived up to 307 m deep and showed cyclical depth movement patterns, with some individuals moving through the water column both day and night, whereas others moved almost exclusively at night. The concentration of blood metabolites did not significantly change with time-on-hook. Conclusion Post-capture and post-release survival of 100% after up to 4 h on hooks suggested that the use of longlines for surveying sandbar shark abundance had no deleterious effects on captured sharks. Implication This will support future stock assessments of sharks by quantifying the survival rates in the methods used for long-term monitoring of sandbar shark populations.

Testimonials to reconstruct past abundances of wildlife populations

Long-term monitoring of wildlife populations has greatly contributed to our current understanding of population dynamics and ecosystem functioning. Despite tireless field campaigns, however, only a fraction of the biodiversity has been monitored to date and the dynamics of potential key species have yet to be understood.Here, we propose a method based on testimonials of observations from field workers to reconstruct past abundances of unmonitored populations and fill data gaps.We contacted scientists who conducted field work at the Bylot Island field station, Nunavut, in the Canadian Arctic between 1991 and 2019 and collected 205 testimonials of past observations from 131 participants. We scored each testimonial based on its content and derived annual abundance indices for three highly fluctuating taxa, being lemmings, snowy owls and ermines. These indices were compared to standardized abundance estimates based on field sampling that were either available between 1993 and 2019 (lemmings and snowy owls) or 2007–2019 (ermines).Our results show that abundance indices based on testimonials correlate well with those from systematic sampling and can be used to detect ecological phenomena. Moreover, we show that abundance indices were not affected by the effort of participants in the field or the delay between the observations and the collection of testimonials. Finally, we use the received testimonials to generate the longest ermine time series of relative abundance in the Canadian Arctic, spanning 29 years.Monitoring programs and research stations often have access to a pool of past participants (e.g. field workers, ecotourists) whose observations can be localized in time. As we strive to gain a deeper understanding of ecosystem functioning, tapping the memories of these people can provide valuable information on the past abundances of unmonitored populations and help answer hypotheses that would otherwise require years of systematic monitoring.

Sustainable elk harvests in Alberta with increasing predator populations

Large predators often are believed to cause declines in hunter harvests of ungulates due to direct competition for prey with hunters. In Alberta, predators of elk (Cervus elaphus), including grizzly bear (Ursus arctos), cougar (Puma concolor), and wolf (Canis lupus), have increased in recent years. We used trend analysis replicated by Wildlife Management Unit (WMU) to examine regional trends in elk harvest and hunter success. Over a 26-yr period, average harvest of elk increased by 5.46% per year for unrestricted bull and by 6.64% per year for limited-quota seasons. Also, over the same time frame, average hunter success increased by 0.2% per year for unrestricted bull and by 0.3% per year for limited-quota seasons, but no trend was detected in hunter effort (P>0.05). Our results show that increasing large-predator populations do not necessarily reduce hunter harvest of elk, and we only found evidence for this in Alberta's mountain WMUs where predation on elk calves has reduced recruitment. Furthermore, data indicate that Alberta's elk harvest management has been sustainable, i.e., hunting has continued while populations of elk have increased throughout most of the province. Wildlife agencies can justify commitments to long-term population monitoring because data allow adaptive management and can inform stakeholders on the status of populations.

Human-induced deforestation increases extinction risk faster than climate pressures: Evidence from long-term monitoring of the globally endangered Milne-Edward's sifaka

Anthropogenic pressures continue to drive the decline of animal populations and loss of ecosystems they inhabit, as is the case for many nonhuman primates. Climate change can significantly exacerbate ongoing human pressures and therefore mitigating actions are urgently needed if we are to avert impending extinctions. Quantitative extinction risk assessments of threatened species are crucial but rarely done due the lack of long-term monitoring of populations in the wild. We assessed the risk of decline and extinction for the endangered Milne-Edward's sifaka (Propithecus edwardsi) – a primate endemic to southeastern Madagascar experiencing deforestation of its habitat which is also affected by cyclones and drought. We built stochastic population models for the species using 34-year population demographic data together with climatologies of cyclones and drought from the same period and the information on anthropogenic pressures within its range. Our results revealed that human-induced deforestation is the most influential variable affecting species decline over the next two decades, with the species becoming more susceptible to cyclones and drought towards the end of the 21st century. Against this backdrop, forest law enforcement, community forest management and economic incentives for community-based conservation must be implemented to tackle proximate deforestation causes. We additionally found that expansion of protected areas could support the recovery potential of Milne-Edward's sifaka from anthropogenic pressures, and therefore further investment in protected area establishment and management, with explicit consideration of the wellbeing of local communities, must be a priority.

Golden Eagle Nesting Territory Distribution in Wind Energy Landscapes of the Southern Great Plains

Abstract Deaths of four Golden Eagles (Aquila chrysaetos) due to collision trauma at a new wind energy facility in east-central New Mexico during 2004–2005 prompted concerns about the species' population status in the encompassing Southern Great Plains region, primarily because its breeding distribution there was poorly documented and wind energy development was expanding rapidly. Therefore, we conducted aerial searches for Golden Eagle nests across northeastern New Mexico, northwestern Texas, western Oklahoma, and adjacent portions of Colorado and Kansas during 2006–2009 and 2015–2020. We delineated five Golden Eagle Nest Search Areas (NSAs) with unique physiographic/geological origins. Individual NSAs were searched partially or entirely for up to 8 yr. Collectively, we identified 123 nesting territories (NTs) occupied by Golden Eagles ≥ 1 yr, of which 94 (76%) were in northeastern New Mexico. The most NTs (40) were in the 11,720-km2 Highlands NSA. Greatest NT density (126.6 km2/NT) and shortest NT nearest neighbor distance (7.4 km) were in the 3533-km2 Northern Caprock NSA. Wind turbines existed near (within 3.2 km) eight nests distributed among five of 28 NTs in the Northern Caprock and were planned for sites in two occupied NTs. Elsewhere, only potential turbines were near nests and only within six NTs. The number of nesting territories we found underscores the importance of the Southern Great Plains to Golden Eagles, even though this region lies at the eastern margin of the species' western North American breeding range. Our data provide strong support for protecting breeding habitat from potential threats, particularly those posed by wind energy development, and are also a foundation for long-term population monitoring.

Population Status of the Suwannee Alligator Snapping Turtle (Macrochelys suwanniensis) in the Suwannee River, Florida

Freshwater megafauna populations, which are declining worldwide, are well known but often overlooked and understudied compared with marine and terrestrial megafauna. One species of freshwater megafauna is the Suwannee alligator snapping turtle (Macrochelys suwanniensis), which is endemic to the Suwannee River drainage in Georgia and Florida. Several trapping studies have examined M. suwanniensis distribution, body size, and population structure, but little information exists regarding its population status. The objectives of our study were to 1) estimate population size, 2) estimate apparent survival, and 3) model population growth rates (k) by conducting a capture–mark–recapture study of M. suwanniensis in the Suwannee River in Florida. From 2011 to 2013, we repeatedly sampled 12 randomly selected 5-km sites along the Suwannee River for M. suwanniensis using baited hoop-net traps. We captured 126 individuals and had 29 recaptures. Both adult males and adult females had very high apparent survival (0.99), whereas juveniles had lower apparent survival (0.32). We estimated a population density of 6.6 turtles/river km, indicating a population of 1709 (95% CI, 1205–2694) M. suwanniensis from the town of White Springs to the upper limit of the estuary in the main stem of the Suwannee River (approximately 259 river km). We constructed 2 postbreeding census matrix population models for M. suwanniensis and incorporated parameters from this study and from the literature. Both matrix population models suggested a slightly decreasing population (k = 0.99), but because of the uncertainty around our estimates, we consider the population trend to be unclear. Elasticity analysis revealed that k was most sensitive to changes in adult survival compared with other model components. This is a conservation concern because adult M. suwanniensis may be incidentally killed by fishing gear. Our study was short-term, and our analyses had limitations; therefore, we recommend future areas of research, including long-term population monitoring.

Annual Censuses and Citizen Science Data Show Rapid Population Increases and Range Expansion of Invasive Rose-Ringed and Monk Parakeets in Seville, Spain.

Simple SummaryMonitoring programs are crucial to understanding and managing invasive species populations. However, they are infrequent and not usually conducted in the long term. In this work, we used population censuses and observational data from citizen science platforms to monitor the growth and expansion of populations of two invasive species established in Seville (Spain): the rose-ringed parakeet and the monk parakeet. During our study period (2013–2021), rose-ringed and monk parakeet populations increased fivefold and twentyfold, respectively. These rapid population growths coincided with the increasing number of observations of both species recorded by volunteer birdwatchers, as well as the increasing expansion of monk parakeets throughout the study area. Citizen science can be useful for roughly knowing the population status of invasive species, but it cannot replace specific monitoring programs to understand their spatiotemporal dynamics.Population changes of invasive species can go unnoticed long before population explosions, so long-term monitoring programs are needed to assess changes in population size. Although invasive populations of rose-ringed (Psittacula krameri) and monk parakeets (Myiopsitta monachus) are present worldwide, their current status and dynamics are mostly poorly known. Here, we provide a long-term population monitoring of both parakeet species established in a Mediterranean urban area. Between 2013 and 2021, we conducted systematic population censuses in the city of Seville and collected their occurrence and spatial distribution data from citizen science platforms. Our censuses showed a rapid population growth of both species: rose-ringed parakeets increased from 1200 to 6300 individuals, while monk parakeets increased from 70 to 1487 individuals. These population trends were weakly reflected by the number of parakeet observations and the number of cells with parakeet observations but not by the number of individuals recorded in citizen science platforms. Moreover, for the monk parakeet, the number of cells with observations was related to the spatial spread of its nests across the study area. Although resource-intensive, long-term monitoring programs are essential to assess population changes and develop effective management actions for invasive species. Thus, contrasting this information with data taken through citizen science platforms can validate the utility of the latter for assessing population status of invasive species.