Positive Population Growth Rates Research Articles

Temperature dependence and genetic variation in resource acquisition strategies in a model freshwater plant

Abstract Understanding how competition varies with environmental stress is critical to anticipating species and community responses to rapid environmental change. While the stress‐gradient hypothesis predicts the strength of competition to decrease with increasing stress, our understanding of how competition varies with stress is limited by a lack of mechanistic understanding of how resource‐use traits underlying competitive dynamics respond to stress. Here, we use duckweeds in the Lemna species complex to measure how phenotypic and genetic variation in R* (a resource acquisition trait representing the minimum resource requirement for positive population growth) varies with high‐temperature stress to better understand how stress alters competitive ability for essential resources. We found that heat stress increased the R* of Lemna plants for nitrogen acquisition. Because lower R* values predict dominance in competitive dynamics where resources are limiting, this indicates that under stressful, high temperatures, plants could experience reduced competitive ability due to the higher resources required to sustain positive population growth rates. We found minimal genetic variation in R* across 11 local genotypes within the Lemna species complex, indicating that selection on resource acquisition strategies for essential resources such as nitrogen may be constrained in nature. The expression of genetic variation in R* for nitrogen was further reduced under heat stress, suggesting that the response to selection for R* could be particularly constrained under high‐temperature stress. Contrary to predictions drawn from the gleaner–opportunist trade‐off, we did not find evidence for a trade‐off in resource acquisition strategies under benign conditions or high‐temperature stress. Plants with lower R* (i.e. higher growth rates under lower nitrogen levels) were not constrained to have lower growth rates under higher nitrogen levels, possibly because the chosen genotypes have not diverged across resource acquisition strategies or because Lemna spp. has escaped this constraint. Importantly, our work indicates that high‐temperature stress could increase sensitivity to competition through an increased requirement for resources while reducing the evolutionary potential for Lemna species to respond to selection for resource traits. This study acts as a key step to understanding the mechanistic traits behind competitive dynamics in resource‐limited and stressful environments. Read the free Plain Language Summary for this article on the Journal blog.

Threats to the persistence of sugar pine (Pinus lambertiana) in the western USA

This study assesses how numerous stressors shape the vital rates (survival, growth, and fecundity) of sugar pine across the vast majority of its range. Sugar pine (Pinus lambertiana Dougl.) is the largest Pinus species, an important timber species, and a component of several dry conifer forest types of western North America, in particular the extensive Sierra Nevada mixed conifer forest. The species faces several challenges in the Anthropocene, including a disrupted fire regime, an invasive pathogen, forest structure changes, and drought with ensuing bark beetle epidemics. Managers are concerned about the conservation outlook for sugar pine, but it is unclear where and how to best invest conservation resources. Using data from the US Forest Service’s Forest Inventory and Analysis program, we estimate the parameters for the vital rate functions and use these to construct an integral projection model which predicts the effects of various stressors on the asymptotic population growth rate. The asymptotic population growth rate is near or slightly below one even under reference conditions, and the actual abundance (in terms of both stem density and basal area) slightly declined over the duration of the study (2001–2019). The analysis reveals that wildfire, white pine blister rust, and forest density are key drivers of the demographic rates of sugar pine across its range. Drought and site dryness had lesser, but still meaningful, effects. Fire has strong negative effects on survival, resulting in a strongly negative population trajectory on burned sites. Conversely, lower than average forest density (plot-level basal area) results in a positive population growth rate via beneficial effects on individual growth. These results highlight the value of fire hazard mitigation, particularly where it also reduces forest density, in the conservation of this important species.

Life-cycle modeling reveals high recovery potential of at-risk wild Chinook salmon via improved migrant survival

Chinook salmon ( Oncorhynchus tshawytscha) in the Columbia River basin are threatened by anthropogenic changes to migratory corridors, estuaries, and natal habitats. Streams provide spatially heterogeneous natal habitats essential for salmon spawning and rearing life stages. We fit a statistical state-space model to salmon populations in Idaho's Middle Fork Salmon River (MFSR) to assess spatial variation in natal productivity and population growth. Our model integrated multiple long-term data sets to estimate variation in per-capita smolt production and smolt-to-adult (SAR) survival. Smolt production varied across stream segments, averaging 104.48 female smolts per spawning female, while SARs averaged 0.74%. Chinook salmon population growth rates exceeded replacement in 17% of segments (4 of 23). By increasing SARs to 1.8% (near the lower bound of Columbia River basin recovery targets), we predict that all 23 MFSR segments will yield positive population growth rates at contemporary (very low) spawner densities. Our analysis suggests that for Snake River basin populations within high-quality natal habitats, SAR improvements will elevate salmon population growth rates and enhance restoration of at-risk wild Chinook salmon.

Defining valid breeding goals for animal breeds

BackgroundThe objective of any valid breeding program is to increase the suitability of a breed for its future purposes. The approach most often followed in animal breeding for optimizing breeding goals assumes that the sole desire of the owners is profit maximization. As this assumption is often violated, a generalized approach is needed that does not rely on this assumption.ResultsThe generalized approach is based on the niche concept. The niche of a breed is a set of environments in which a small population of the breed would have a positive population growth rate. Its growth rate depends on demand from prospective consumers and supply from producers. The approach involves defining the niche that is envisaged for the breed and identifying the trait optima that maximize the breed’s adaptation to its envisaged niche within the set of permissible breeding goals. The set of permissible breeding goals is the set of all potential breeding goals that are compatible with animal welfare and could be reached within the planning horizon of the breeding program. In general, the breed’s adaptation depends on the satisfaction of the producers with the animals and on the satisfaction of the consumers with the products produced by the animals. When consumers buy live animals, then the breed needs to adapt to both the environments provided by the producers, and the environments provided by the consumers. The profit function is replaced by a more general adaptedness function that measures the breed’s adaptation to its envisaged niche.ConclusionsThe proposed approach coincides with the traditional approach if the producers have the sole desire to maximize their income, and if consumer preferences are well reflected by the product prices. If these assumptions are not met, then the traditional approach to breeding goal optimization is unlikely to result in a valid breeding goal. Using the example of companion breeds, this paper shows that the proposed approach has the potential to fill the gap.

Analisis Daya Dukung Lahan Perkebunan di Kabupaten Garut Provinsi Jawa Barat

Garut Regency produces agricultural and plantation commodities that support the city's and surrounding districts' food needs. On the other hand, Garut Regency is also experiencing a positive population growth rate from 2010 to 2020. This increase in growth rate has implications for several problems, one of which is the increasing land conversion from agricultural land to built-up land. This increase in land use change causes the ability of land to complement plantation commodities to decrease. This study aims to analyze the carrying capacity of plantation land and the variety of commodities in the carrying capacity of plantation land in the surplus category. RTRW and elevation of the carrying capacity of plantation land in Garut Regency using descriptive methods with analysis of land carrying capacity. Surplus and six sub-districts experienced a deficit in the land's carrying capacity, and the tobacco commodity became the leading commodity in all sub-districts. Based on the RTRW and elevation of the carrying capacity of land allotted for plantations, the most extensive is in the Cibalong sub-district, with an area of ​​around 33.97% with a very high surplus category. The location (ha) in the type of reduction to elevation is the highest, with a spread between 250-2000 masl in Bungbulang District. This research is hoped to be used as material input in land policies in Garut Regency regarding regional planning and plantation commodities.

The ecological causes of functional distinctiveness in communities.

Recent work has shown that evaluating functional trait distinctiveness, the average trait distance of a species to other species in a community offers promising insights into biodiversity dynamics and ecosystem functioning. However, the ecological mechanisms underlying the emergence and persistence of functionally distinct species are poorly understood. Here, we address the issue by considering a heterogeneous fitness landscape whereby functional dimensions encompass peaks representing trait combinations yielding positive population growth rates in a community. We identify four ecological cases contributing to the emergence and persistence of functionally distinct species. First, environmental heterogeneity or alternative phenotypic designs can drive positive population growth of functionally distinct species. Second, sink populations with negative population growth can deviate from local fitness peaks and be functionally distinct. Third, species found at the margin of the fitness landscape can persist but be functionally distinct. Fourth, biotic interactions (positive or negative) can dynamically alter the fitness landscape. We offer examples of these four cases and guidelines to distinguish between them. In addition to these deterministic processes, we explore how stochastic dispersal limitation can yield functional distinctiveness. Our framework offers a novel perspective on the relationship between fitness landscape heterogeneity and the functional composition of ecological assemblages.

Reversing declines in farmland birds: How much agri‐environment provision is needed at farm and landscape scales?

Abstract Agri‐environment schemes (AES) are the primary policy mechanism for addressing farmland biodiversity declines across Europe. Despite previous studies on the impacts of AES on biodiversity, there is little empirical evidence on the scale of provision required to reverse declines. Across three regions of lowland England with contrasting farm systems (arable, pastoral, mixed), we estimated avian population growth rates (PGRs) on farmland with high AES provision (‘higher‐tier’: average bird‐friendly option cover = 7.4%), low AES provision (‘lower‐tier’: 2.3%) and no bird‐friendly AES (‘no AES’). Ten‐year PGRs were derived for 24 species and three multi‐species groups comprising farmland‐associated species (‘farmland birds’), species of conservation concern (‘priority birds’) and species restricted to farmland (‘specialist birds’). We used PGRs to simulate the proportion of the regional farmland landscape that would have to be assigned to higher‐ and lower‐tier agreements to stabilise or increase populations. In the arable and pastoral regions, 13/23 and 13/22 species, respectively, had more positive PGRs under higher‐tier AES than on no AES farmland (none had more negative PGRs), compared to 4/22 (positive) and 1/22 (negative) in the mixed region. Only two to four species per region exhibited more positive PGRs under lower‐tier AES compared to no AES farmland. Multi‐species PGRs in the arable and pastoral regions increased from no AES (strong decline), to lower‐tier (decline or stability) to higher‐tier (moderate or strong increase). There was no overall AES effect in the mixed region. To increase regional farmland bird populations by 10% over 10 years, 47% and 26% of the farmed landscape would need to be devoted to higher‐tier agreements in arable and pastoral landscapes respectively. This falls to 34% and 17% when higher‐tier is targeted at localities supporting higher abundances of target species, and to 29% and 10% when 30% of the farmed landscape is also devoted to lower‐tier. Priority and specialist birds require higher provision levels. Policy implications. Where farmland bird recovery is an AES objective, farms should prioritise higher‐tier agreement delivery over lower‐tier. Farmland bird responses to AES provision are likely to vary regionally, but careful targeting will reduce the amount needed in the landscape.

Demographic consequences of management actions for the successful reintroduction of the White Stork Ciconia ciconia to the UK

Summary Species reintroductions can be used in conservation management to increase biodiversity and aid in restoring ecosystem function. For reintroductions to be successful, it is important to identify the conditions required to establish a viable population. We developed a demographic model using Vortex10, an individual-based simulation software, to assess the long-term consequences of different management interventions on the success of the recent reintroduction of the white stork, Ciconia ciconia, to the UK. Demographic data obtained from this reintroduced population were supplemented with information from western European populations to build the models. The impact of incorporating different management actions (e.g. supplementing with captive-bred juveniles, provision of nesting platforms, and habitat improvement/supplementary feeding) on the stochastic population growth rate was assessed. Survival rates also differ depending on an individual’s migratory strategy, hence we tested the impact of having different proportions of the population as residents or migrants. Our models showed that if the British stork population adopts a fully migratory strategy, with its associated higher mortality rates, i.e. all individuals migrating to southern Europe or northern Africa, increasing the supplementation rate would not lead to a positive population growth rate. However, management actions which increased the number of fledglings per nest generated a slight positive growth rate that led to a 54.3% increase in population size after 50 years and, when combining all three management options, the population grew by 378.3%. Alternatively, if a minimum of 9% of individuals overwintered in Britain, which is likely based on field observations and tracking data, a positive growth rate can be achieved without additional management due to this behaviour’s lower mortality rates. We conclude that the British white stork population will likely be viable in the long term, but these models and projections should be updated as more demographic data on this novel population become available.

Incorporating temporal dynamics to enhance grazing management outcomes for a long‐lived species

Abstract Identifying successful management strategies for long‐lived species is challenging, especially in fluctuating environments, because the response of individual vital rates and overall growth rates to management action can vary over time. A demographic approach that isolates the impact of management and environment on individual vital rates, and assesses their importance for growth rate over time, can indicate whether and why a management strategy is successful. Here we take a demographic approach to assess the success of grazing management for the perennial grass Stipa pulchra, California's state grass and a focus on conservation efforts. We tracked S. pulchra populations in paired grazed and ungrazed plots over 6 years, which included a historic drought and an El Niño rain year, and calculated summary transition matrices for the main effects of year, grazing and year × grazing interaction for each site. We averaged these summary transition matrices to calculate population growth rates, λ, for the main effects of year, grazing and year × grazing and used life table response experiment (LTRE) analysis to compare how individual vital rates contributed to differences in λ between grazed and ungrazed plots over time. Overall we found that grazing was a successful management strategy; grazed populations maintained a positive average population growth rate whereas ungrazed populations declined. We found that grazing had a larger positive effect on growth rates in wet years than drought years. This was because grazed populations benefited from a greater contribution of adult growth immediately following the end of the drought compared with ungrazed populations and from adult survival thereafter. Synthesis and applications. Although Stipa pulchra is the focus of many management efforts, the use of grazing for management is contentious, and there have been few studies that take a demographic approach to understanding S. pulchra responses over time. Our results indicate that conservation and restoration efforts should move beyond recruitment to focus on adult growth and survival for overall population success. To this end, moderate grazing can be a successful strategy to maintain S. pulchra populations and is particularly important in wet years to promote plant growth.

Small giants: Tributaries rescue spatially structured populations from extirpation in a highly fragmented stream

Abstract Habitat fragmentation is a pervasive threat to biodiversity. Linearly arranged habitats such as stream networks are particularly vulnerable to fragmentation. As the landscape becomes increasingly human dominated, conservation values of fragmented habitat patches cannot be overlooked. It is critical to understand the demographic mechanisms of population persistence or extirpation in fragmented patches. We studied dynamics of spatially structured populations of two Japanese landlocked salmonids persisting for >30 years in a headwater stream network that is highly fragmented due to low‐head dams in the mainstem. We parameterised and analysed spatial matrix population models using 9‐year mark–recapture data. Tributaries supported higher survival rates in some life stages, and movement was asymmetrical from the tributaries to the mainstem. Accordingly, population growth rates were higher in the tributary patches than the mainstem in both species despite the tributaries occupying only 12% or 18% of the study stream network by surface area. The tributaries harboured more physically and hydraulically complex instream habitats (i.e. higher wood density and flow refugia), indicating that habitat patch quality was more important than habitat patch size in determining the dynamics of these spatially structured populations. Tributary locations in the stream network were important in the trajectory of these populations. The upstream‐dwelling charr persisted in the highly fragmented mainstem patch (i.e. six impassable infrastructures in a <500 m patch) due to immigration of fish from upstream including the tributary. However, the downstream‐dwelling salmon has been gradually extirpated from the uppermost section of the fragmented mainstem patch because they could not maintain a positive population growth rate after loss of emigrants was accounted for and immigration was prevented due to fragmentation. Synthesis and applications. We conclude that small tributaries have rescued the spatially structured populations from extirpation (charr) or at least slowed down extirpation (salmon). Legal protection of headwaters as aquatic habitats is weak globally. Our results suggest that stream management plans underestimating the demographic value of small tributaries will likely fail to conserve populations of headwater inhabitants and therefore endanger aquatic biodiversity. We discuss conservation implications of this study related to habitat connectivity and fisheries management.

Urban scaling of opioid overdose deaths in the USA: a cross-sectional study in three periods between 2005 and 2017

ObjectivesTo describe the association between population size, population growth and opioid overdose deaths—overall and by type of opioid—in US commuting zones (CZs) in three periods between 2005 and 2017.Settings741 CZs...

Context-dependent variation in persistence of host populations in the face of disease.

Research Highlight: Valenzuela-Sánchez, A., Azat, C., Cunningham, A. A., Delgado, S., Bacigalupe, L. D., Beltrand, J., Serrano, J. M., Sentenac, H., Haddow, N., Toledo, V., Schmidt, B. R., & Cayuela, H. (2022). Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen. Journal of Animal Ecology, 00, 1- 12. https://doi.org/10.1111/1365-2656.13603. Understanding the nuances of population persistence in the face of a stressor can help predict extinction risk and guide conservation actions. However, the exact mechanisms driving population stability may not always be known. In this paper, Valenzuela-Sánchez et al. (2022) integrate long-term mark-recapture data, focal measurements of reproductive effort, a population matrix model and inferences on life-history variation to reveal differences in demographic response to disease in a susceptible frog species (Rhinoderma darwinii). Valenzuela-Sánchez et al. found that demographic compensation via recruitment explained the positive population growth rate in their high disease prevalence population whereas the low disease prevalence population did not compensate and thus had decreasing population growth. Compensatory recruitment was likely due to the high probability of males brooding, and the high number of brooded larvae in the high prevalence population compared to low prevalence and disease-free populations. Valenzuela-Sánchez et al. also document faster generation times in the high prevalence population, which may indicate a faster life history that may be contributing to the population's ability to compensate for reduced survival. Lastly, the authors find a positive relationship between disease prevalence and the proportion of juveniles in a given population that suggest that there may be a threshold for disease prevalence that triggers increased reproductive effort. Altogether, their study provides novel support for increased reproductive effort as the pathway for compensatory recruitment leading to increasing population growth despite strong negative effects of disease on adult survival. Their results also caution the overgeneralization of the effects of stressors (e.g. disease) on population dynamics, where context-dependent responses may differ among host populations of a given species.

The Disconnect Between Short- and Long-Term Population Projections for Plant Reintroductions

The reintroduction of rare species in natural preserves is a commonly used restoration strategy to prevent species extinction. An essential first step in planning successful reintroductions is identifying which life stages (e.g., seeds or large adults) should be used to establish these new populations. Following this initial establishment phase, it is necessary to determine the level of survival, growth, and recruitment needed to maintain population persistence over time and identify management actions that will achieve these goals. In this 5-year study, we projected the short- and long-term population growth rates of a critically endangered long-lived shrub, Delissea waianaeensis. Using this model system, we show that reintroductions established with mature individuals have the lowest probability of quasi-population extinction (10 individuals) and the highest increase in population abundance. However, our results also demonstrate that short-term increases in population abundances are overly optimistic of long-term outcomes. Using long-term stochastic model simulations, we identified the level of natural seedling regeneration needed to maintain a positive population growth rate over time. These findings are relevant for planning future reintroduction efforts for long-lived species and illustrate the need to forecast short- and long-term population responses when evaluating restoration success.

Demographic profile of Gjirokastra region

Nowadays, demographic change is one of the key challenges for local development, without forgetting, climate change, development of the green economy, inclusiveness and poverty. Strategic solutions cannot be based on addressing one of these factors alone but must take into account the interplay of these elements within a particular local area of development, urban or rural. (Cristina Martinez&al,2012). According to the latest administrative-territorial reform of local government, the number of municipalities in Albania, has been reduced from 370 to 61 municipalities, while the number of regions still remained unchanged at 12. The reform does not imply changes in the number of population at the region level, but has brought drastic changes at the municipality level. While the population at the national and regional level has been declined, the population in the new administrative units has been “increased” almost doubled, due to the merger of the former municipalities with rural areas, “bringing” in the same-time multiplication of problems related to the need of implementing efficient management of natural and human resources of new administrative units. More specifically in January 1,2021, the Albanian resident population has reached about 2.82 million inhabitants or a decrease compared to last year for about 0,6% and compared to year 2001 for about 8.3%. The only exception during this period is the year 2017 in which a positive population growth rate was recorded for about 0.03%. The highest annual rate decline of the national population for the same period, was recorded in 2020, estimated for about -0,58 %. The greatest positive contribution to the annual growth rate of national population is "offered" by Tirana and Durrës municipalities, meanwhile the rest of municipalities have contributed negatively to the annual growth rate of population.

Demography of a Eurasian lynx (Lynx lynx) population within a strictly protected area in Central Europe

Large carnivores promote crucial ecosystem processes but are increasingly threatened by human persecution and habitat destruction. Successful conservation of this guild requires information on long-term population dynamics obtained through demographic surveys. We used camera traps to monitor Eurasian lynx between 2009 and 2018 in a strictly protected area in the Bohemian Forest Ecosystem, located in the core of the distribution of the Bohemian–Bavarian–Austrian lynx population. Thereby, we estimated sex-specific demographic parameters using spatial capture–recapture (SCR) models. Over 48,677 trap nights, we detected 65 unique lynx individuals. Density increased from 0.69 to 1.33 and from 1.09 to 2.35 individuals/100 km2 for open and closed population SCR models, respectively, with corresponding positive population growth rates (mean = 1.06). Estimated yearly sex-specific survival probabilities for the entire monitoring period were high (females 82%, males 90%) and per capita recruitment rate was low (females 12%, males 9%), indicating a low yearly population turnover. We ascertained an average number of recruits of 1.97 and a generation time of 2.64 years when considering resident reproducing females. We confirmed that reproduction in the study area took place successfully every year. Despite the overall increase in local lynx densities, the number of detected family groups remained constant throughout the study period. These results indicated that the strictly protected study area acts as a source for the multi-use landscapes in its surroundings. In this first open population SCR study on lynx, we provide sex-specific demographic parameters that are fundamental information for lynx management in the study area as well as in similar contexts Europe-wide.

Population reinforcement and demographic changes needed to stabilise the population of a migratory vulture

Abstract One approach to stabilise small and declining populations is to breed individuals in captivity and release them into the wild to reinforce existing populations while working to reduce threats. Population reinforcement programmes require long‐term commitments to be successful and can divert limited resources from other conservation measures. A rigorous evaluation whether reinforcement can stabilise a population is therefore essential to justify investments. Many migratory species incur high mortality during their first migration, and releasing captive‐bred birds at an older age may therefore benefit reinforcement programmes for migratory birds. We examine whether a small and declining population of a long‐distance migratory raptor—the Egyptian Vulture Neophron percnopterus—can be stabilised using population reinforcement that reduces mortality during the first migration. We used an integrated population model to evaluate realistic reinforcement and survival improvement scenarios to estimate how many captive‐bred birds would need to be released to stabilise the population. Survival probability of wild juveniles during their first year (0.296; 95% CI 0.234–0.384) was too low for a stable population (population growth rate 0.949; 95% CI 0.940–0.956), but captive‐bred juveniles released in their second calendar year had improved survival (0.566; 95% CI 0.265–0.862) during their first year in the wild. Reinforcement of 15 birds per year for 30 years was insufficient to achieve a neutral or positive population growth rate. However, reinforcement reduced the probability of extinction by 2049 from 48% without reinforcement to <1% if 12 or more birds were released every year for 30 years. A 6% increase in annual survival probability would likely lead to a stable population without any reinforcement. Synthesis and applications. Although releasing captive‐bred birds can reduce high juvenile mortality during first migration and assist in postponing local extinction, further improvements of survival in the wild are required to safeguard a migratory population where threats in the wild will persist for decades despite management.

Climate change and grassland management interactively influence the population dynamics of Bromus erectus (Poaceae)

Climate and land management are important environmental drivers that affect the structure of terrestrial plant communities worldwide. Demographic studies allow a mechanistic understanding of the pathways in which environmental factors change population size. Climate and land management might interactively influence vital rates and growth rates of populations, however, demographic studies have not heretofore considered both factors in combination. We used the Global Change Experimental Facility as a platform to study the effect of climate (ambient climate conditions vs. future climate conditions) and land management (sheep grazing vs. mowing) on the demography of the common grass, Bromus erectus growing in semi-natural grassland communities. Using an integral projection model, we found positive population growth rates for B. erectus under all treatment combinations, and an interactive effect of climate and land management. Under ambient climate conditions, population growth of B. erectus was higher in mowed than grazed grassland plots, while population growth rates were similar across both management types under future climatic conditions. This interaction was primarily due to between-treatment changes in seedling recruitment, a vital rate to which the population growth rate is particularly sensitive. The interaction found in this study highlights the importance of considering multiple environmental drivers in demographic studies, to better predict future plant population dynamics and ultimately changes in community structure.

Long‐term community dynamics in vascular epiphytes on Annona glabra along the shoreline of Barro Colorado Island, Panama

Abstract Despite the ecological importance of vascular epiphytes in the tropics, even basic information on the processes that form epiphyte communities is scarce. This is partially due to an almost complete lack of long‐term studies. Here, we present data that were collected in three consecutive censuses over 21 years in a monospecific host tree system that is about 100 years old and interpret them in an empirical and a metapopulation/metacommunity framework. We documented an ongoing increase in abundance and diversity at the level of the entire system (metacommunity) and at the level of communities (all epiphytes growing on individual Annona glabra tree stands). This was also reflected at the population level; >2/3 of the species showed positive population growth rates. Similarly, colonisation of empty Annona trees was still ongoing, with the most abundant species being also the first to colonise empty trees. The community composition of colonised trees became more similar with time. In all three censuses, habitat size of epiphytes explained much of the variation in species richness among stands (groups of trees with individual trees within 25 m of each other) and overall abundant species tended to be more abundant at the stand scale. The species frequency distribution was unimodal, regardless of whether considering all stands or only stands with very large epiphyte communities, indicating that the metacommunity still has not reached an equilibrium phase. Similarly consistent in both census intervals, population growth rates decreased with increasing population size with substantial asynchrony among populations. Synthesis. In contrast to a typical herbaceous plant community, this epiphyte metacommunity is still expanding after one century of development. Our study shows that previously reported short‐term patterns of epiphyte community dynamics hold true in the long term. It remains to be shown, however, whether results from this monospecific host tree system are really representative for epiphyte community dynamics in more diverse tropical forests.

The application of vector autoregressive integrated with exogenous variable to model the relationship between covid-19 positive numbers with population growth rate

The Vector Autoregressive Integrated with Exogenous Variable (VARIX) model can be used to examine the relationship between covid-19 positive case numbers (as endogenous variables) and population growth rate (as exogenous variables) while predicting covid-19 positive case numbers. In this paper, we apply the VARIX model to covid-19 phenomena in two regencies/cities in West Java Province, Bandung and Purwakarta. The results of the analysis show that the VARIX model is a suitable model used to describe the intended relationship. The VARIX model has a good forecasting ability characterized by a relatively small MAPE value. The exogenous variables show positive results, so it can be concluded that the positive covid-19 numbers in Bandung City and Purwakarta Regency have a positive correlation with the population growth rate in West Java Province.

Implementation of the Far Eastern Hectare program as a tool to improve land management in the Khabarovsk Territory

By the end of the first decade of the 21st century, an extremely serious migration situation had developed in the Far Eastern region of the Russian Federation, which was characterized by the alarming rate of population outflow from this already sparsely populated region of the country. Between 1991 and 2010, according to various estimates, the population of the Far East decreased by 1.8 million people or by 22%. Of all the constituent entities of the Russian Federation that are part of the Far Eastern Federal District, not one is characterized by positive population growth rates. In this regard, the Government has developed a number of measures aimed at breaking the tense migration situation. The so-called “Far Eastern hectare” has become the main instrument for the implementation of the new migration and economic policies in this region. The article sets forth material related to the development of proposals to ensure the sustainable development of rural territories of the Far Eastern Federal District of the Russian Federation through the implementation of the Far Eastern Hectare program. The practical significance lies in the fact that the results of the study can be useful in identifying and forming land for the Far Eastern Hectare program.