The fragmented population structure of the Sardinian chalk hill blue butterfly (Lepidoptera, Lycaenidae)

The endemic Sardinian chalk hill blue butterfly, Polyommatus coridon gennargenti, is considered vulnerable to extinction because of its low genetic variation and restricted distribution. The species also has a fragmented distribution, which follows the patchy distribution pattern of its larval host-plant. A preliminary investigation of the population structure of P. coridon gennargenti was carried out on a small network of four local populations by means of capture–recapture methods. Estimated population sizes and movement rates among the four adjacent local populations suggest that this taxon has a metapopulation structure composed of loosely connected small local populations. Natural fragmentation, isolation, and traditional land use contribute to the vulnerability of P. coridon gennargenti to extinction. Low effective population sizes and restricted movement between habitat patches lead to inbreeding and an increased vulnerability to extinction of this island population.     

Analysis of geographic centrality and genetic diversity in the declining grasshopper species Bryodemella tuberculata (Orthoptera: Oedipodinae)

Human-induced ecological and climatic changes have led to the decline and even local extinction of many formerly widely distributed temperate and cold-adapted species. Determining the exact causes of this decline remains difficult. Bryodemella tuberculata was a widely distributed orthopteran species before the mid-19th century. Since then, many European populations have suffered drastic declines and are now considered extinct or critically endangered. We used ecological niche modelling based on a large dataset of extant and extinct occurrence data to investigate whether poor climatic suitability in the periphery of its global range was a possible cause of the local extinction of the European populations of B. tuberculata. We also used population genetics based on the COI marker to estimate and compare the genetic diversity of extant populations. We found that Europe still provides highly suitable habitats close to the climatic optimum, contradicting the assumption of climate change as major driver of this decline. Instead, changes in land-cover and other anthropogenic modifications of the habitats at the local scale seem to be the major reasons for local extinctions. Genetic analysis suggests Central Asia as center of diversity with a stable population size, whereas the effective sizes of the remaining European populations are decreasing. We found European genetic lineages nested within Central Asian lineages, suggesting a Central Asian source distribution area. Our results suggest that the declining European populations represent relics of a formerly wider distribution, which was fragmented by changes in land-use. These relics are now threatened by limited connectivity and small effective population sizes. Specific conservation actions, such as the restoration of former or potential new habitats, and translocation of individuals from extant populations to these restored sites may help slow, stall, or even revert the extinction process.

     

Early colonisation population structure of a Norway rat island invasion

Colonists undergo non-equilibrium processes such as founder effects, inbreeding and changing population size which influence the mating system and demography of a population. Understanding these processes in colonising populations informs management and helps prevent further invasions. We sampled and genotyped most individuals of a Norway rat (Rattus norvegicus) reinvasion on Moturemu island (5 ha) in New Zealand. Population size was most likely between 30 and 33 rats. Genetic methods detected a clear bottleneck signal from the founding population. Parentage assignment revealed promiscuous mating dominated by a few individuals with increasing inbreeding, both putatively a result of small island size. Combining ecological and genetic data from a single sample allowed inferences on population structure and functioning. Invading Norway rats rapidly achieve population structure similar to established island populations despite a small number of colonists and associated inbreeding. Overcoming these initial obstacles to population establishment contributes to the global success of invasive rats.     

Ancient DNA sequences point to a large loss of mitochondrial genetic diversity in the saiga antelope (Saiga tatarica) since the Pleistocene

Prior to the Holocene, the range of the saiga antelope (Saiga tatarica) spanned from France to the Northwest Territories of Canada. Although its distribution subsequently contracted to the steppes of Central Asia, historical records indicate that it remained extremely abundant until the end of the Soviet Union, after which its populations were reduced by over 95%. We have analysed the mitochondrial control region sequence variation of 27 ancient and 38 modern specimens, to assay how the species’ genetic diversity has changed since the Pleistocene. Phylogenetic analyses reveal the existence of two well‐supported, and clearly distinct, clades of saiga. The first, spanning a time range from >49 500 ¹⁴C ybp to the present, comprises all the modern specimens and ancient samples from the Northern Urals, Middle Urals and Northeast Yakutia. The second clade is exclusive to the Northern Urals and includes samples dating from between 40 400 to 10 250 ¹⁴C ybp. Current genetic diversity is much lower than that present during the Pleistocene, an observation that data modelling using serial coalescent indicates cannot be explained by genetic drift in a population of constant size. Approximate Bayesian Computation analyses show the observed data is more compatible with a drastic population size reduction (c. 66–77%) following either a demographic bottleneck in the course of the Holocene or late Pleistocene, or a geographic fragmentation (followed by local extinction of one subpopulation) at the Holocene/Pleistocene transition.     

High genetic diversity in a small population: the case of Chilean blue whales

It is generally assumed that species with low population sizes have lower genetic diversities than larger populations and vice versa. However, this would not be the case for long‐lived species with long generation times, and which populations have declined due to anthropogenic effects, such as the blue whale (Balaenoptera musculus). This species was intensively decimated globally to near extinction during the 20th century. Along the Chilean coast, it is estimated that at least 4288 blue whales were hunted from an apparently pre‐exploitation population size (k) of a maximum of 6200 individuals (Southeastern Pacific). Thus, here, we describe the mtDNA (control region) and nDNA (microsatellites) diversities of the Chilean blue whale aggregation site in order to verify the expectation of low genetic diversity in small populations. We then compare our findings with other blue whale aggregations in the Southern Hemisphere. Interestingly, although the estimated population size is small compared with the pre‐whaling era, there is still considerable genetic diversity, even after the population crash, both in mitochondrial (N = 46) and nuclear (N = 52) markers (H_d = 0.890 and H_o = 0.692, respectively). Our results suggest that this diversity could be a consequence of the long generation times and the relatively short period of time elapsed since the end of whaling, which has been observed in other heavily‐exploited whale populations. The genetic variability of blue whales on their southern Chile feeding grounds was similar to that found in other Southern Hemisphere blue whale feeding grounds. Our phylogenetic analysis of mtDNA haplotypes does not show extensive differentiation of populations among Southern Hemisphere blue whale feeding grounds. The present study suggests that although levels of genetic diversity are frequently used as estimators of population health, these parameters depend on the biology of the species and should be taken into account in a monitoring framework study to obtain a more complete picture of the conservation status of a population.     

Synergistic effects of an extreme weather event and habitat fragmentation on a specialised insect herbivore

Habitat fragmentation is considered to be one of the main causes of population decline and species extinction worldwide. Furthermore, habitat fragmentation can decrease the ability of populations to resist and to recover from environmental disturbances such as extreme weather events, which are expected to occur at an increasing rate as a result of climate change. In this study, we investigated how calcareous grassland fragmentation affected the impact of the climatically extreme summer of 2003 on egg deposition rates, population size variation and survival of the blue butterfly Cupido minimus, a specialist herbivore of Anthyllis vulneraria. Immediately after the 2003 summer heat wave, populations of the host plant declined in size; this was paralleled with decreases in population size of the herbivore and altered egg deposition rates. In 2006 at the end of the monitoring period, however, most A. vulneraria populations had recovered and only one population went extinct. In contrast, several butterfly populations had gone extinct between 2003 and 2006. Extinction probability was significantly related to initial population size, with small populations having a higher risk of extinction than large populations. These results support the prediction that species of higher trophic levels are more susceptible to extinction due to habitat fragmentation and severe disturbances.     

Do smaller islands host younger populations? A case study on metapopulations of three carabid species

Aims To test a new concept for island ecology and metapopulation studies: if population persistence is a result of colonization and extinction processes, one would expect remarkable variability in the age of neighbouring populations – there would be both old and young (recently established) populations. Location The lake Mamry archipelago, Poland. Methods Forty trap transects with a total of 114 Barber traps were operating from June to September in 1997 and in 1998. The traps (0.5‐L plastic beakers, mouth diameter 120 mm, with a 20 × 20 cm wooden roof) were placed by applying a stratified sampling design into 13 habitat types on the 16 islands and two mainland sites. The frequency of macropterous individuals in wing‐dimorphic populations of three carabid species (Pterostichus melanarius, P. anthracinus and Carabus granulatus) was used as an indicator of population ‘age’. Results The frequency of macropterous individuals in the populations varied from 0% to 100% for P. melanarius (18.5% on average), from 0% to 91% for P. anthracinus (12.6%) and from 0% to 29% for C. granulatus (8.9%). Populations hosted more long‐winged individuals (and were therefore interpreted as being younger) on smaller islands, compared with those inhabiting large islands and the mainland sites. The results also revealed that the viability of the populations of the autumn‐breeding P. melanarius might be more affected by population size than that of the two studied spring breeders. Island connectivity did not have a significant effect on the frequency of macropterous individuals in the studied populations. Main conclusions The inverse relationship between the proportion of macropterous individuals and island size contrasts with the accepted theory of dispersal, which assumes that there is selection against dispersal on small islands. A regression analysis for population age and habitat characteristics reveals the extinction probability of a given population. I suggest that investigations based on variability in population age can help in studies of colonization–extinction processes that would otherwise face logistic and methodological obstacles.     

NEUTRAL GENETIC DIVERSITY IN A METAPOPULATION WITH RECURRENT LOCAL EXTINCTION AND RECOLONIZATION

Many species exist as metapopulations in balance between local population extinction and recolonization, processes that may strongly affect the distribution of neutral genetic diversity within demes and in the metapopulation as a whole. In this paper we use both the infinite-alleles and the infinite-sites models to reframe Slatkin's propagulepool and migrant-pool models in terms of mean within-deme and among-deme genetic diversity; the infinite-sites model is particularly relevant to DNA sequence data. Population turnover causes a major reduction in neutral genetic diversity within demes, π_S, and in the metapopulation as a whole, π_t. This effect is particularly strong for propagulepool colonization, in which colonists are drawn from a single extant deme. Because metapopulation dynamics affect both within-deme and total metapopulation diversity similarly, comparisons between species with different ecologies on the basis of ratios such as F_ST are difficult to interpret and absolute measures of divergence between populations should be used as well. Although the value of F_ST in a metapopulation with local extinction depends strongly on the mode of colonization, this has almost no effect on the numerator of the F_ST ratio, π_t – π_S, so that F_ST is influenced mainly by the effect of the colonization mode on the denominator (π_t). Our results also indicate that it is inappropriate to use measures of average within-deme diversity in species with population turnover to estimate the scaled mutation rate, θ, because extinction can greatly reduce π_S. Finally, we discuss the effect of population turnover on the effective size of a metapopulation.     

阿尔金山自然保护区基于野牦牛、藏野驴、藏羚羊适宜栖息地的生态容量估测

阿尔金山国家级自然保护区保护了以野牦牛(Bos mutus)、藏野驴(Equus kiang)、藏羚羊(Pantholops hodgsoni)为代表的青藏高原特有野生动物及其栖息地,但是近年来野生动物数量的快速增长引发了栖息地退化的问题,科学量化阿尔金山自然保护区各类栖息地对野牦牛、藏羚羊、藏野驴的生态容量,并提出相应的野生动物管理措施,是实现保护区可持续管理的根本途径。本文应用遥感技术和地面调查相结合的方法,系统分析了保护区内野牦牛、藏野驴和藏羚羊的栖息地需求,建立了植物生物量和NDVI的关系模型,结合三类野生动物的食性分析,估测了适宜栖息地(高寒草原、高寒荒漠草原、高寒草甸、高寒荒漠)为三类野生动物提供的可食植物量,推算了适宜栖息地和整个保护区可以承载三类野生动物的生态容量。结果表明:阿尔金山自然保护区内野牦牛、藏野驴和藏羚羊的适宜栖息地面积分别为31866.07、24035.51、24035.51 km~2,三类野生动物的适宜栖息地之间相互重叠,藏野驴和藏羚羊的适宜栖息地基本相同;全保护区内,高寒草原、高寒荒漠草原、高寒荒漠和高寒草甸分别提供了3944.91×10~4、3126.32×10~4、138.19×10~4、564.49×10~4kg可食植物量;结合三类野生动物的栖息地重叠程度及食物需求量分析,得出阿尔金山保护区的最大生态容量为野牦牛7951头/a、藏野驴6907头/a、藏羚羊27094只/a;结合三类野生动物对食物资源的占有率估计,得出阿尔金山三类野生动物的生态容量变幅为野牦牛3976—7156头/a,藏野驴3454—6216头/a、藏羚羊13547—24385只/a。根据阿尔金山自然保护区各类栖息地对三类野生动物的生态容量,提出适当控制藏野驴种群数量、增加藏羚羊种群数量的建议,以促进野生动物种群数量的持续增长和栖息地的有效保护。     

Genetic structure analysis of a highly inbred captive population of the African antelope Addax nasomaculatus. Conservation and management implications

The African antelope Addax nasomaculatus is a rare mammal at high risk of extinction, with no more than 300 individuals in the wild and 1,700 captive animals distributed in zoos around the world. In this work, we combine genetic data and genealogical information to assess the structure and genetic diversity of a captive population located at Parque Lecocq Zoo (N=27), originated from only two founders. We amplified 39 microsatellites previously described in other Artiodactyls but new to this species. Seventeen markers were polymorphic, with 2–4 alleles per locus (mean=2.71). Mean expected heterozygosity (He) per locus was between 0.050 (marker ETH3) and 0.650 (marker D5S2), with a global He of 0.43. The mean inbreeding coefficient of the population computed from pedigree records of all registered individuals (N=53) was 0.222. The mean coancestry of the population was 0.298 and F_IS index was ?0.108. These results reflect the importance of an adequate breeding management on a severely bottlenecked captive population, which would benefit by the incorporation of unrelated individuals. Thanks to the successful amplification of a large number of microsatellites commonly used in domestic bovids, this study will provide useful information for the management of this population and serve as future reference for similar studies in other captive populations of this species. Zoo Biol 30:399–411, 2011. © 2010 Wiley‐Liss, Inc.     

Population dynamics of the cactus Mammillaria gaumeri: an integral projection model approach

The Cactaceae family in Mexico is particularly important because members of this family exhibit a high degree of endemism. Unfortunately, many species of the Cactaceae are threatened or endangered. We employed an integral projection model for studies of the population dynamics of Mammillaria gaumeri, an endemic cactus of the Yucatán characterized by a small population size. The integral projection model provides estimates of the asymptotic growth rate, stable size distribution, reproductive values, and sensitivities and elasticities of the growth rate to changes in vital rates. Nine locations of this species were studied along the Yucatan coast over a 9-year period. Individuals were classified by plant volume. Most population growth rate (λ) values were below unity. The highest elasticity values corresponded to the survival of intermediate size individuals. The percentage of germination in the field was low, and consequently, fecundity values were also low. Reproductive values were observed to increase with plant volume. The stable size distribution of M. gaumeri was skewed toward small individuals. For all years, the kernel showed that individual survival determined the population growth rate.     

Population status and distribution modelling of the critically endangered riverine rabbit (Bunolagus monticularis)

The riverine rabbit (Bunolagus monticularis) is one of the most endangered mammals in the world due to fragmentation of its habitat in the semi‐arid Karoo region of South Africa, to which it is endemic. It is an umbrella conservation species for the riparian shrubland associated with the seasonal drainage system of the Karoo, where its presence is an indicator of ecosystem health. In this study, we analysed historical survey data to derive an improved assessment of the current B. monticularis population status and distribution. Geospatial analysis was conducted using geographical information systems, and distribution modelling was performed using Maxent. Extent of occurrence for the species is 54,227 km², and area of occupancy is 2943 km². Estimates of 157–207 mature individuals confirm an alarmingly small species population size, and it appears that no subpopulation has >50 mature individuals. Our findings thus support the continued classification of this species as ‘critically endangered’ under IUCN Red List criteria. However, with most remaining habitat occurring outside of protected areas, and with habitat loss being exacerbated by climate change, a viable conservation plan remains elusive.     

Considering threats to population viability of the endangered Korean long-tailed goral (Naemorhedus caudatus) using VORTEX

Population viability analysis (PVA) has frequently been used in conservation biology to predict extinction rates for threatened or endangered species. In this study, we used VORTEX to model Korean long-tailed goral (Naemorhedus caudatus) using previously collected ecological data. We focused on modelling population extinction, mean population size and heterozygosity. The minimum viable population size was found to be at least 50 gorals for 100 years, regardless of carrying capacity. However, populations with fewer than 50 gorals could not remain successful in the model. Inbreeding depression, catastrophes and supplementation also affected patterns of population extinction, mean population size and heterozygosity. Supplementation with new individuals had the strongest effect on extinction, mean population size and heterozygosity, followed by initial population size, inbreeding, catastrophes and carrying capacity. These results suggest that a supplementation by extra goral individuals from goral proliferation facilities would be the most helpful means for the restoration programme. More Korean goral-specific information regarding demographic and habitat parameters is needed for further PVA of the species.     

Population growth of Mexican free-tailed bats (Tadarida brasiliensis mexicana) predates human agricultural activity

Background  

Human activities, such as agriculture, hunting, and habitat modification, exert a significant effect on native species. Although many species have suffered population declines, increased population fragmentation, or even extinction in connection with these human impacts, others seem to have benefitted from human modification of their habitat. Here we examine whether population growth in an insectivorous bat (Tadarida brasiliensis mexicana) can be attributed to the widespread expansion of agriculture in North America following European settlement. Colonies of T. b. mexicana are extremely large (~10⁶ individuals) and, in the modern era, major agricultural insect pests form an important component of their food resource. It is thus hypothesized that the growth of these insectivorous bat populations was coupled to the expansion of agricultural land use in North America over the last few centuries.     

Estimate of population extinction risk and its application to ecological risk management

Environmental threats, such as habitat size reduction or environmental pollution, may not cause immediate extinction of a population but may shorten the expected time to extinction. We developed a method to estimate the mean time to extinction for a density-dependent population with environmental fluctuation and to compare the impacts of different risk factors. We first derived a formula of the mean extinction time for a population with logistic growth and environmental and demographic stochasticities expressed as a stochastic differential equation model (canonical model). The relative importance of different risk factors is evaluated by the decrease in the mean extinction time. We studied an approximated formula for the reduction in habitat size that enhances extinction risk by the same magnitude as a given decrease in survivorship caused by toxic chemical exposure. In a large population (large K) or in a slowly growing population (small r), a small decrease in survivorship can cause the extinction risk to increase, corresponding to a significant reduction in the habitat size. Finally, we studied an approximate maximum likelihood estimate of three parameters (intrinsic growth rate r, carrying capacity K, and environmental stochasticity σ ² _e ) from time series data. By Monte Carlo sampling, we can remove the bias very effectively and determine the confidence interval. We discuss here how the reliability of the estimate changes with the length of time series. If we know the intrinsic rate of population growth r, the mean extinction time is estimated quite accurately even when only a short time series is available for parameter estimation. Received: March 31, 1999 / Accepted: November 9, 1999     

Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution,Population Size and Extinction Risk

The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km². During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation.     

<Emphasis Type="Italic">Taxus baccata</Emphasis> in the Azores: a relict form at risk of imminent extinction

Taxus baccata L., a Tertiary relict formerly widespread in the Azores Archipelago, was recently classified as “probably extinct”. This paper documents the persistence of the species in the Azores and provides its first characterization by means of morphometric and genetic analyses. Only five individuals were found, growing on Pico Island. Although the population size is critically small it retains some highly significant characteristics for the assessment of the genetic diversity of the species and its phylogeography. The leaves of the Azorean provenance were smaller than those of all other Taxus baccata described in literature; moreover, they have a higher stomata density and more numerous stomata rows. These features are all “primitive”, according to suggested morphological evolutionary trends. We assume that sequence analysis of the chloroplast trnS–trnQ intergenic spacer demonstrates that the Azorean population represents a different evolutionary line within Taxus. This suggests a more direct derivation from ancestors than provenances from Mediterranean and European regions. These individuals may be the last survivors of an ancient lineage, preserved in the Azores as part of the Macaronesian flora. Immediate conservation action focusing on site protection and ex situ reproduction strategies is recommended to save this lineage from imminent extinction.     

Return of the native facilitated by the invasive? Population composition,substrate preferences and epibenthic species richness of a recently discovered shellfish reef with native European flat oysters (Ostrea edulis) in the North Sea

After being ecologically extinct for almost a century, the discovery of a shellfish reef with native European flat oysters (Ostrea edulis) in the Dutch coastal area of the North Sea by the authors of this study called for an extensive survey to better understand some of the key requirements for the return of the native oyster in coastal waters. We assessed habitat conditions, its potential for increasing biodiversity, and the role of substrate provision by other bivalves such as the invasive alien Pacific oyster (Crassostrea gigas). Using underwater visual census, O. edulis size-frequency distributions and attachment substrate was investigated, as well as the composition of the epibenthic community and substrata types inside quadrats that were distributed across the reef. This reef was found to be composed of native European flat oysters, invasive alien Pacific oysters and blue mussels (Mytilus edulis), alternated with sandy patches. The O. edulis population (6.8?±?0.6 oysters m^?2) consisted of individuals of different size classes. In quadrats with native and non-native oysters the number of epibenthic species was 60% higher compared to adjacent sand patches within the reef. Notably, our results showed that the native oyster predominantly used shell (fragments) of the invasive Pacific oyster as settlement substrate (81% of individuals). Our results optimistically show that conditions for native oyster restoration can be suitable at a local scale in the coastal North Sea area and suggest that the return of native oysters may be facilitated by novel substrate provided by invasive oysters at sites where their distribution overlap.     

Diversity,habitats and size-frequency distribution of the gastropod genus Conus at Dahab in the Gulf of Aqaba,Northern Red Sea

Topographically complex subtidal reefs of the Indo-West Pacific region are characterised by a high species richness of cone snails of the genus Conus (up to 36 on some reefs) but low population densities (≤1 individual/m²), whereas Conus assemblages on reef flats usually support fewer species (5–9) and high population densities (up to 5.2 individuals/m²). Subtidal sand areas are known to be least species-rich (1–6 species). Although the diversity of this predatory gastropod genus has been described previously from different areas of the Indo-Pacific, little ecological information is available on Conus in the Northern Red Sea. Therefore, data from five habitat types were obtained along 73 line-transects (245?m²⁾, which yielded ecological data for a total of 175 individuals of 9 species. In accordance with former findings, our results demonstrate that the reef flat was the habitat with the highest observed population densities (6.15 individuals/m²) but low species diversity (H’ = 0.9; 5 species); subtidal reefs, in contrast, were characterised by low densities (0.13 individuals/m²) and a relatively high species diversity (H ‘= 1.5; 6 species). This suggests that Conus diversity and species richness in the Northern Red Sea around Dahab is lower than in other parts of the Indo-West Pacific region. Furthermore, hardand soft substrata were dominated by different Conus species in accordance to the distribution of favourable microhabitat patches, the degree of physical stress and the availability of refuges and prey organisms. The fact that these Conus were predominantly small-bodied vermivores (size range: 6–85?mm; mean shell size: 15?mm; SD = 9?mm) suggests that this size class possesses an advantage over molluscivores and piscivores. Except for subtidal reefs, which showed a highly variable species composition, the studied habitat types around Dahab were characterised by distinct assemblages of Conus.     

The uses,local perceptions and ecological status of 16 woody species of Gadumire Sub-county,Uganda

Populations of naturally growing woody species valued for their contribution to human livelihoods are threatened with extinction. Most at risk are those existing in human inhabited areas outside protected areas that are subjected to high population pressure and to a variety of land use demands. The sustainable utilization of these plants requires as a first step knowledge, including, their ecology and an understanding of the peoples attitudes to conservation. This study was conducted to generate data that would contribute to the management for conservation and sustainable use of woody resources. The study objectives were to document local knowledge covering the uses, status, threats, habitats and management solutions of woody species; determine the abundances, distribution and population structure of 16 woody species, and assess the conservation status of the selected woody species. The study was carried out in Gadumire Sub-county, Uganda using both an ethnobotanical approach and quantitative ecological methods. The species are multipurpose and are exploited to satisfy different subsistence needs. They had population densities ranging between 3.6 and 2630 individuals ha⁻¹, and distributions ranging between 0.3 and 39.5%. The species Acacia hockii, Albizia zygia, Acacia seyal, Markhamia lutea and Albizia coriaria had a good conservation status. The remainder of the species appear threatened either because they had low densities, frequencies or less steep size class distribution (SCD) slopes. Securidaca longipedunculata Fres. was not encountered at all in the study plots. Community perceptions collaborated the measured population dynamics. The major threats believed to be impacting the species by the community are the growing human population, expanding crop agriculture, poor harvesting methods and over-exploitation of the species.