Field Of Conservation Biology Research Articles

Microhabitat and seasonal influence on bess beetle (Coleoptera: Passalidae) assemblage in Altitudinal Atlantic Forest

AbstractUnderstanding the spatiotemporal distribution of diversity has been a significant challenge in the field of conservation biology. Presently, there exists a limited understanding of the spatial distribution of passalid beetles within decomposing logs, as well as their distribution in microhabitats such as the cortex, heartwood and trunk–soil interface. Moreover, there is a scarcity of studies that delve into the temporal distribution patterns of passalid beetles. We evaluate the effect of seasons of the year and microhabitats on the distribution of passalid in an Altitudinal Atlantic Forest. More specifically, the effects of the period of the year and microhabitats were analysed on an assemblage scale and population structure scale. Collections were actively conducted monthly, during dry and rainy seasons, and distinct microhabitats of logs (tree cortex, heartwood and trunk–soil interface) were sampled. We discovered passalid galleries within 235 logs, housing a total of 785 individuals representing nine species across six genera and two tribes. Within the three examined microhabitats, the heartwood and cortex harboured the majority of individuals. In contrast, the trunk–soil interface microhabitat displayed reduced diversity and abundance and the absence of indicator species, exhibiting a distinct community structure compared with the others. The dry season stood out with a greater number of individuals, underscoring the influence of precipitation on passalid activity in this study. Our study contributes to understanding the ecological dynamics of these insects and evaluating their resilience to current landscape transformations on the planet.

Comparative genomics reveals convergent adaptations in lipid metabolism and low genetic diversity in carnivorous bats

AbstractDietary specialization stands as a major factor in the study of adaptive evolution and the field of conservation biology among animals. Although bats show unparalleled dietary diversification among mammals, specialized carnivory remains relatively rare within this group. Consequently, our comprehension of the genetic and conservation aspects associated with this specific dietary niche in bats has largely remained uncharted. To investigate molecular adaptations and conservation genetics in carnivorous bats, we produced a new draft genome assembly for the carnivorous bat Vampyrum spectrum. Furthermore, we utilized this genome alongside another distantly related carnivorous bat Megaderma lyra, to conduct genome‐wide comparative analyses with other bat species. Our findings unveil that genes linked to lipid metabolism exhibit signatures of positive selection and convergent molecular adaptation in the two divergent lineages of carnivorous bats. Intriguingly, we have uncovered that the evolution of dietary specialization in carnivorous bats is accompanied by molecular adaptations acting on genes in the peroxisome proliferator‐activated receptors pathways, which are crucial in regulating plasma lipid metabolism and sustaining lipid homeostasis. Additionally, our genomic analyses also reveal low genetic diversity in both carnivorous bat species. This pattern is attributed to their continuously declining population sizes and low levels of heterozygosity, signaling their vulnerability and emphasizing the pressing need for conservation efforts. These genomic discoveries advance our understanding of genetic underpinnings of carnivory in bats and underscore substantial conservation concerns associated with carnivorous bat species.

Software-dependent biases in the recognition of di- and tri-syllabic bird songs can create false interpretations of bird abundance and singing activity

The use of autonomous recording units (ARUs) for passive acoustic monitoring has recently gained a lot of importance. It is now widely used for scientific purposes and has been increasingly applied in the field of conservation biology. However, while ARUs may greatly increase cost-effectiveness in monitoring, they are not exempt from possible biases. In this study, we compared the performances of three different software in recognizing bi- and tri-syllabic bird songs and tested if their results varied significantly in a real setting. We focused on the interpretation of the relative abundance among habitats and the time of vocal activity, also using different numbers of training records to assess if the results of the software improved. Even with the quality measures of the recognizer being consistent with those of previously published studies, in several cases the results produced significantly different interpretations depending on the software used. While increasing the number of training records slightly improved the overlap in the estimates of activity among the different software, differences in the relative abundance of each song were present even with a fairly solid number of training records. Our results suggest that reliable biological interpretations might only be attained with a large number of training records and very high values of precision, recall, and the F-score. In fact, even with very high precision and F-scores, lower values for recall led not only to statistically significant differences, but also to different interpretations of relative abundance and time of activity between the two best-performing software. Thus, great caution must be taken in interpreting the results of bioacoustics studies that use automated recognition, and standards of minimum quality should be created for recognizers in scientific and technical studies.

Assisting adaptation in a changing world

Today, all ecosystems are undergoing environmental change due to human activity, and in many cases the rate of change is accelerating due to climate change. Consequently, conservation programs are increasingly focused on the response of organisms, populations, and ecosystems to novel conditions. In parallel, the field of conservation biology is developing and deploying new tools to assist adaptation, which we define as aiming to increase the probability that organisms, populations, and ecosystems successfully adapt to ongoing change in biotic and abiotic conditions. Practitioners are aiming to assist a suite of adaptive processes, including acclimatization, range shifts, and evolution, at the individual and population level, while influencing the aggregate of these responses to assist ecosystem reorganization. The practice of assisting adaptation holds promise for environmental conservation, but effective policy and implementation will require thoughtful consideration of potential social and biological benefits and risks.

Exploring the opportunities and risks of aerial monitoring for biodiversity conservation

Drones are unoccupied aerial systems (UAS) whose technology has evolved rapidly over the past 15 years. Increasingly used in conservation to manage and monitor biodiversity, drones offer rich capabilities to observe in difficult terrain, have relatively affordable hardware costs and are likely to continue to proliferate rapidly in the years ahead. Drones are useful for tasks as diverse as monitoring wildlife poaching and illegal timber extraction, managing ecotourism and disaster responses, and tracking the regeneration or degradation of forests, and offer potential for more specialised tasks as their sensory payloads are developed. However, although associated technical issues and applications have been explored in wide-ranging ways within conservation science, there has been relatively little social-scientific engagement with drones to date. This leaves a gap surrounding the potential social benefits and risks of drones, as well as in interdisciplinary conversations. This introduction is the first of four papers under the heading ‘Drone ecologies’, building on an interdisciplinary workshop held under the same name at the University of Bristol in July 2021. Expanding from the plenary dialogues that opened this workshop, this introduction explores what interdisciplinary perspectives on drones can offer in addressing global social and ecological challenges, drawing on expertise from the fields of conservation biology, human and physical geography, rainforest ecology and environmental systems. Setting out the aims of the overall special collection, we review here the ways that drones are being used, and might be used, in biodiversity conservation, setting out important considerations to minimise risks of inadvertent harms.

Investigation and control strategy for canine distemper disease on endangered wild dog species: a model-based approach

The canine distemper virus (CDV) is a major threat to the already endangered wild dogs. We propose an evidence-based mathematical model of canine distemper in the wild to predict the rate and possibility of disease spread in wild dogs under a different scenario. We find the endemic and disease-free equilibrium points and the condition for their stability from the model. The bifurcation analysis of the model shows how the endemic equilibrium can be transformed into the disease-free equilibrium through parameters that represent fundamental ecological properties. The sensitivity of these parameters to the secondary disease spread points out the specific interaction rates and a birth rate that should be targeted to reduce the CDV outbreak. We suggest target parameters for controlling the disease outbreak considering the plausibility of manipulating them in terms of implications besides the sensitivity of the parameters. Finally, this article proposes two specific control strategies based on this modeling framework: isolation and birth-control-reintroduction. Since the isolation strategy may be cost-intensive, we modify our model to quantify the isolation rate necessary to reduce the disease outbreak. We suggest that the birth-control-reintroduction strategy based on the proposed model is cost-effective for a small contaminated area. Overall, the models in this study is applied in the field of conservation biology.

Meeting at the crossroads

As global environmental changes continue to accelerate, research and practice in the field of conservation biology may be essential to help forestall precipitous declines in the earth’s ability to sustain a diversity of life. However, many conservation programs have faced scrutiny for the social injustices they create, especially within the paradigm of demarcating protected lands. Currently, a new conservation paradigm emphasizing landscapes shared by people and wildlife is emerging, and with it, an opportunity to ensure that justice for both human and beyond-human groups is given consideration. Here, we examine a practice emblematic of this new conservation paradigm, the reintroduction and recovery of large carnivore species, and draw from theories in environmental justice to detail the many forms of justice at stake in these efforts. Our analysis shows that a pluralistic application of justice is required to ensure that new conservation practices do not produce and reproduce injustices for people. In addition, we show that the success of these emerging programs in meeting their conservation goals in fact depends on meaningfully addressing a range of justice concerns. By developing this framework, we also identify domains in which environmental justice scholarship can expand its scope. To this end, we introduce the novel concept of affective environmental justice, which describes the complex role of emotions as environmental harms, as disruptors of understanding other forms of justice, and as links between logics of oppression. Our framework offers a comprehensive resource to work through in planning and implementing large carnivore reintroduction and recovery programs, and we conclude by describing the challenges and opportunities for further aligning conservation and environmental justice in research and practice.

Intentional Ecology: Integrating environmental expertise through a focus on values, care and advocacy

As the significance of environmental degradation for humanity becomes apparent, the challenge of developing expertise in integrating science, advocacy and implementation has been acknowledged. Addressing recent and ongoing global challenges including mass extinction, climate change, disease and threats to food, water and power security requires employment of evidence-based science in multi-faceted approaches. Ensuring the mobilisation of new knowledge in practice, both in policy and on-ground actions, takes many researchers into the realm of advocacy, where facts and values become equally important. In the nexus between research and practice, guidance in integrating approaches is required. Drawing on the fields of conservation biology, systems theory and feminist science, this paper offers a new conceptual framework to guide researchers and professionals; one that supports practice by encouraging action and advocacy. The framework, intentional ecology, requires examination of ethics and acknowledgement of the human endeavour that supports curiosity and care in research. Intention is the key concept here as it incorporates beliefs, choice and actions. A case study of the application of intentional ecology to research into, and conservation of, a small, threatened amphibian, Sloane’s Froglet, in South Eastern Australia is provided. Many environmental issues are complex and it is difficult to find a single point to address. While acknowledging that complexity, intentional ecology provides an ethical basis and imperative to act. In so doing intentional ecology enables early, applied and relevant integrated action and reflexive and dynamic approaches to implementation.

The crucial role of genome-wide genetic variation in conservation

The unprecedented rate of extinction calls for efficient use of genetics to help conserve biodiversity. Several recent genomic and simulation-based studies have argued that the field of conservation biology has placed too much focus on conserving genome-wide genetic variation, and that the field should instead focus on managing the subset of functional genetic variation that is thought to affect fitness. Here, we critically evaluate the feasibility and likely benefits of this approach in conservation. We find that population genetics theory and empirical results show that conserving genome-wide genetic variation is generally the best approach to prevent inbreeding depression and loss of adaptive potential from driving populations toward extinction. Focusing conservation efforts on presumably functional genetic variation will only be feasible occasionally, often misleading, and counterproductive when prioritized over genome-wide genetic variation. Given the increasing rate of habitat loss and other environmental changes, failure to recognize the detrimental effects of lost genome-wide genetic variation on long-term population viability will only worsen the biodiversity crisis.

Population genetic structure and gene flow of rare and endangered Tetraena mongolica Maxim. revealed by reduced representation sequencing

BackgroundStudying population genetic structure and gene flow of plant populations and their influencing factors is of particular significance in the field of conservation biology, especially important for species such as rare and endangered plants. Tetraena mongolica Maxim. (TM), belongs to Zygophyllaceae family, a rare and endangered plant with narrow distribution. However, for the last decade, due to excessive logging, urban expansion, industrial and tourism development, habitat fragmentation and loss of natural habitats have become major threats to the population of endangered plants.ResultsIn this study, genetic diversity, population genetic structure and gene flow of TM populations were evaluated by reduced representation sequencing technology, and a total of more than 133.45 GB high-quality clean reads and 38,097 high-quality SNPs were generated. Analysis based on multiple methods, we found that the existing TM populations have moderate levels of genetic diversity, and very low genetic differentiation as well as high levels of gene flow between populations. Population structure and principal coordinates analysis showed that 8 TM populations can be divided into two groups. The Mantel test detected no significant correlation between geographical distances and genetic distance for the whole sampling. Moreover, the migration model indicated that the gene flow is more of a north to south migration pattern in history.ConclusionsThis study demonstrates that the present genetic structure is mainly due to habitat fragmentation caused by urban sprawl, industrial development and coal mining. Our recommendation with respect to conservation management is that, all 8 populations should be preserved as a whole population, rather than just those in the core area of TM nature reserve. In particular, the populations near the edge of TM distribution in cities and industrial areas deserve our special protection.

Engaging a global Facebook audience with conservation education

Sharing information is a critical component of conservation science. Transferring this information from conservation scientists to the general public can be accelerated with the use of social media. Conservation practitioners and educators can utilize social media to display information, promote causes, and engage the public. Although social media has the potential to be a vessel for conservation education, there are few studies discussing the impact of social media on conservation education or on post timing for a global Facebook audience. To improve the success of these efforts, we sought to understand the effect of day of the week and time of day on Facebook post engagement. Data was collected from the Facebook page of the Cheetah Conservation Fund (CCF), a global leader in cheetah conservation rooted in education, research, and the mitigation of human-wildlife conflict. Friday was the most engaging day while the weekend (Saturday–Sunday) had the lowest engagement. The highest average engagement occurred between 9 AM EST and 10 AM EST and the lowest engagement was found between 5 PM EST and 6 PM EST. It is impossible to reach every person with every post, but scheduling posts or geotargeting specific geographical locations may increase engagement. This study is a starting point for global organizations to analyze their Facebook activity in order to conclude when the most engaging times occur in order to reach as many people as possible. Increasing engagement could increase the discussion of important issues in the field of conservation biology.

The Behavioral Economics of Biodiversity Conservation Scientists

Values have a profound influence on the behaviour of all people, scientists included. Biodiversity is studied by ecologists, like myself, most of whom align with the “mission-driven” field of conservation biology. The mission involves the protection of biodiversity, and a set of contextual values including the beliefs that biological diversity and ecological complexity are good and have intrinsic value. This raises concerns that the scientific process might be influenced by biases toward outcomes that are aligned with these values. Retrospectively, I have identified such biases in my own work, resulting from an implicit assumption that organisms that are not dependent on natural habitats (e.g., forests) effectively do not count in biodiversity surveys. Finding that anthropogenic forest disturbance reduces the diversity of plant species dependent on shady forests can thus be falsely equated with more general biodiversity loss. Disturbance might actually increase overall plant diversity (i.e., including all of the species found growing in a particular place). In this paper I ask whether ecologists share values that are unrepresentative of broader society, I discuss examples of potential value-driven biases in biodiversity science, and I present some hypotheses from behavioral economics on possible psychological underpinnings of shared values and preferences among ecologists.

Threatened species conservation of invertebrates in Australia: an overview

AbstractInvertebrates make up about 80% of all species, yet they rarely attract conservation attention compared to the more ‘charismatic’ vertebrates such as birds and mammals. Threatened species conservation, a field of conservation biology in which individual species are targeted for protection and conservation management, complements the landscape approach to biodiversity conservation and could be used more effectively to promote the plight of threatened or imperilled invertebrates given the global biodiversity crisis and estimated rates of anthropogenic species extinction. In this overview, steps in the species‐oriented conservation process are outlined, including conservation status evaluation, listing under legislation, preparation of Action and Recovery Plans, recovery actions, recovery teams and monitoring, in order to prevent extinction or minimise risk of extinction. The process is not without its challenges, but it does provide valuable information that is not always obtainable with the protection and management of threatened ecological communities and habitats. However, to be most effective, a more strategic approach to listing species is required. It is recommended that more national Action Plans, either of higher taxonomic groups or of ‘indicator’ species – suites of species indicative of threatened ecological communities, habitats, biomes, key threatening processes, co‐dependent threatened host species or short‐range endemics – are needed. These plans would provide a national overview of threatened and imperilled invertebrates in conservation need that is far more comprehensive than presently available. A detailed national list of threatened invertebrate species could then be promoted (and nominated for listing under the EPBC Act) for greater conservation advocacy.

An updated checklist of Echinoderms from Indian waters.

Species checklists enlist the species available within the defined geographical region and thus serve as essential input for developing conservation and management strategies. The fields of conservation biology and ecology confront the challenge of inflated biodiversity, attributed to non-recognition of taxonomic inconsistencies such as synonyms, alternate representation, emendations etc. Critical review of the checklists and distributional records of Phylum Echinodermata from Indian waters and subsequent validation of species names with World Register of Marine Species (WoRMS) database, revealed that the current literature included 236 incorrect entries comprising of 162 synonyms, 15 emendations, 5 nomina dubia, 1 nomen nudum, 40 species under alternate representation, 9 species with author misnomer, 1 subspecies and 1 unaccepted. The 226 species found to be mixed with valid names and a revised checklist was prepared. The revised and updated checklist holds 741 species of echinoderms comprising of 182 asteroids (24.56%), 70 crinoids (9.45%), 138 echinoids (18.62%), 179 holothuroids (24.16%) and 172 ophiuroids (23.21%), placed under 28 orders and 107 families. This paper discusses the cause for taxonomic inflation and argues that such taxonomic inconsistencies alter our interpretations of a species including its inaccurate distribution and, could possibly impede the country's conservation and management efforts.

Understanding Sustainability through Traditional Maasai Pastoral Systems in Southern Kenya

In the developed world, we tend to think of sustainability as a newly articulated solution to challenges of environmental resource degradation and issues of social and economic injustice. However, pastoralism as traditionally practiced by the Maasai of southern Kenya is tied closely to the land and responds to climatic variation within the region. In the early 20 th century, colonial policies began to alter traditional land use systems, compromising inherently sustainable arrangements and isolating populations from the land. This trend has continued somewhat in contemporary development practice. As a result of a shift toward privatization of land tenure, traditional pastoral systems are no longer viable. While studying abroad with The School for Field Studies, we became aware of the struggle many Maasai face as they attempt to continue pastoralism in an increasingly hostile environment. Ultimately, development efforts in the region should focus not on implementing exogenous concepts of ‗sustainability‘ but rather on supporting and adapting systems that are already in place. Author’s Note Kaitlyn received an email from Consilience while we were in Kenya. That night, we started talking about sustainability in the context of the Maasai. While we come from different disciplinary backgrounds—Emma is focused on Africana Studies while Kaitlyn‘s background is in Environmental Biology—in Kenya we had both come to understand the inextricable relationship between people and conservation in the developing world. We wanted to share our thoughts on issues of sustainable development, as well as some of the more formative experiences that contributed to our understanding of the complex nature of social and environmental issues in southern Kenya. We‘ve both developed a strong connection to the area. Emma plans to return to southern Kenya and research sustainable agriculture, ultimately working toward a graduate degree in the field. After spending a year in western Kenya studying the behavioral ecology of blue monkeys, Kaitlyn plans to pursue graduate education in the field of conservation biology. She will continue to engage in projects that integrate conservation and development efforts.

Citizen science can improve conservation science, natural resource management, and environmental protection

Citizen science has advanced science for hundreds of years, contributed to many peer-reviewed articles, and informed land management decisions and policies across the United States. Over the last 10years, citizen science has grown immensely in the United States and many other countries. Here, we show how citizen science is a powerful tool for tackling many of the challenges faced in the field of conservation biology. We describe the two interwoven paths by which citizen science can improve conservation efforts, natural resource management, and environmental protection. The first path includes building scientific knowledge, while the other path involves informing policy and encouraging public action. We explore how citizen science is currently used and describe the investments needed to create a citizen science program. We find that:1.Citizen science already contributes substantially to many domains of science, including conservation, natural resource, and environmental science. Citizen science informs natural resource management, environmental protection, and policymaking and fosters public input and engagement.2.Many types of projects can benefit from citizen science, but one must be careful to match the needs for science and public involvement with the right type of citizen science project and the right method of public participation.3.Citizen science is a rigorous process of scientific discovery, indistinguishable from conventional science apart from the participation of volunteers. When properly designed, carried out, and evaluated, citizen science can provide sound science, efficiently generate high-quality data, and help solve problems.

From “What is” to “What Should Become” Conservation Biology? Reflections on the Discipline’s Ethical Fundaments

In this essay, I build on the article by Soule that established the foundation for the field of conservation biology. I analyze the presuppositions that have guided the discipline’s ethics in the 30 years since that article first appeared. I argue that conservation biology’s normative postulates introduced a paradigm shift that placed the diversity of the biota instead of the biota itself at the center of its ethics. I show that the ensuing priorities in the valuation of nature entail several contradictions at the ethical level and are justifiable only through scientific postulates. Identifying potential revisions and latent ideological issues in science, I defend the position that such scientific legitimization of conservation measures becomes disputable when this option undermines the ethical status of non-human life. Furthermore, I explain the absence of social feedback regarding conservation measures from the perspective of this shift. I conclude with an invitation to critically rethink the ethical basis of conservation sciences so that these fields may achieve their intention of playing a key role in halting the destruction of nature and in encouraging society’s support.

Genomic resources and their influence on the detection of the signal of positive selection in genome scans.

Genome scans represent powerful approaches to investigate the action of natural selection on the genetic variation of natural populations and to better understand local adaptation. This is very useful, for example, in the field of conservation biology and evolutionary biology. Thanks to Next Generation Sequencing, genomic resources are growing exponentially, improving genome scan analyses in non-model species. Thousands of SNPs called using Reduced Representation Sequencing are increasingly used in genome scans. Besides, genome sequences are also becoming increasingly available, allowing better processing of short-read data, offering physical localization of variants, and improving haplotype reconstruction and data imputation. Ultimately, genome sequences are also becoming the raw material for selection inferences. Here, we discuss how the increasing availability of such genomic resources, notably genome sequences, influences the detection of signals of selection. Mainly, increasing data density and having the information of physical linkage data expand genome scans by (i) improving the overall quality of the data, (ii) helping the reconstruction of demographic history for the population studied to decrease false-positive rates and (iii) improving the statistical power of methods to detect the signal of selection. Of particular importance, the availability of a high-quality reference genome can improve the detection of the signal of selection by (i) allowing matching the potential candidate loci to linked coding regions under selection, (ii) rapidly moving the investigation to the gene and function and (iii) ensuring that the highly variable regions of the genomes that include functional genes are also investigated. For all those reasons, using reference genomes in genome scan analyses is highly recommended.

Should we call them fishers or fishermen?

Abstract‘Fishermen’ and the gender‐neutral ‘fishers’ are the most common terms used to describe people who fish in the English language. However, there is a considerable debate as to which term is most appropriate. In academic journals, usage of ‘fishers’ for people who fish began in the 1960s and increased over time, until in 2013 and 2014 ‘fishers’ first exceeded usage of ‘fishermen’, despite being labelled ‘archaic’ in the Oxford English Dictionary. In journal searches ‘fishermen’ unambiguously referred to people who fish, but ‘fishers’ also referred to R.A. Fisher's statistical tests (22%), the mammal, Pekania pennanti (5%), and other terms. Journal policies have played a role in the shift to ‘fishers’: e.g. Conservation Biology requires the use of ‘fishers’ while Fishery Bulletin requires ‘fishermen’. Partly as a result, in academia there are disciplinary and geographic variations, with greatest usage of ‘fishers’ in the field of conservation biology and in Australia. Surprisingly, word choice did not differ by the gender of the lead author. Many other languages also have gender‐neutral terms for people who fish (e.g. Austronesian and Turkic languages), yet the word is still assumed to refer to men. While the gender‐neutral term ‘fisher’ is more inclusive it is far from universally accepted, particularly by women and men in the North American fishing industry. The current shift towards the more inclusive term ‘fishers’ highlights the increasing disciplinary diversity within fisheries science, particularly in terms of gender.

Empirical evidence for source-sink populations: a review on occurrence, assessments and implications.

Assessing the role of local populations in a landscape context has become increasingly important in the fields of conservation biology and ecology. A growing number of studies attempt to determine the source-sink status of local populations. As the source-sink concept is commonly used for management decisions in nature conservation, accurate assessment approaches are crucial. Based on a systematic literature review of studies published between 2002 and 2013, we evaluated a priori predictions on methodological and biological factors that may influence the occurrence of source or sink populations. The review yielded 90 assessments from 73 publications that included qualitative and quantitative evidence for either source or sink population(s) for one or multiple species. Overall, sink populations tended to occur more often than source populations. Moreover, the occurrence of source or sink populations differed among taxonomic classes. Sinks were more often found than sources in mammals, while there was a non-significant trend for the opposite to be true for amphibians. Univariate and multivariate analyses showed that the occurrence of sources was positively related to connectivity of local populations. Our review furthermore highlights that more than 25 years after Pulliam's widely cited publication on 'sources, sinks, and population regulation', in-depth assessments of the source-sink status of populations based on combined consideration of demographic parameters such as fecundity, survival, emigration and immigration are still scarce. To increase our understanding of source-sink systems from ecological, evolutionary and conservation-related perspectives, we recommend that forthcoming studies on source-sink dynamics should pay more attention to the study design (i.e. connectivity of study populations) and that the assessment of the source-sink status of local populations is based on λ values calculated from demographic rates.