This paper presents a new and simple method to find indicator species and species assemblages characterizing groups of sites The novelty of our approach lies in the way we combine a species relative abundance with its relative frequency of occurrence in the various groups of sites This index is maximum when all individuals of a species are found in a single group of sites and when the species occurs in all sites of that group; it is a symmetric indicator The statistical significance of the species indicator values is evaluated using a randomization procedure Contrary to TWINSPAN, our indicator index for a given species is independent of the other species relative abundances, and there is no need to use pseudospecies The new method identifies indicator species for typologies of species releves obtained by any hierarchical or nonhierarchical classification procedure; its use is independent of the classification method Because indicator species give ecological meaning to groups of sites, this method provides criteria to compare typologies, to identify where to stop dividing clusters into subsets, and to point out the main levels in a hierarchical classification of sites Species can be grouped on the basis of their indicator values for each clustering level, the heterogeneous nature of species assemblages observed in any one site being well preserved Such assemblages are usually a mixture of eurytopic (higher level) and stenotopic species (characteristic of lower level clusters) The species assemblage approach demonstrates the importance of the ''sampled patch size,'' ie, the diversity of sampled ecological combinations, when we compare the frequencies of core and satellite species A new way to present species-site tables, accounting for the hierarchical relationships among species, is proposed A large data set of carabid beetle distributions in open habitats of Belgium is used as a case study to illustrate the new method

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Species assemblages and indicator species:the need for a flexible asymmetrical approach

Both the magnitude and the urgency of the task of assessing global biodiversity require that we make the most of what we know through the use of estimation and extrapolation. Likewise, future biodiversity inventories need to be designed around the use of effective sampling and estimation procedures, especially for 'hyperdiverse' groups of terrestrial organisms, such as arthropods, nematodes, fungi, and microorganisms. The challenge of estimating patterns of species richness from samples can be separated into (i) the problem of estimating local species richness, and (ii) the problem of estimating the distinctness, or complementarity, of species assemblages. These concepts apply on a wide range of spatial, temporal, and functional scales. Local richness can be estimated by extrapolating species accumulation curves, fitting parametric distributions of relative abundance, or using non-parametric techniques based on the distribution of individuals among species or of species among samples. We present several of these methods and examine their effectiveness for an example data set. We present a simple measure of complementarity, with some biogeographic examples, and outline the difficult problem of estimating complementarity from samples. Finally, we discuss the importance of using 'reference' sites (or sub-sites) to assess the true richness and composition of species assemblages, to measure ecologically significant ratios between unrelated taxa, to measure taxon/sub-taxon (hierarchical) ratios, and to 'calibrate' standardized sampling methods. This information can then be applied to the rapid, approximate assessment of species richness and faunal or floral composition at 'comparative' sites.

Estimating Terrestrial Biodiversity through Extrapolation

A central goal in ecology is to predict population dynamics from demographic information. Based on the asymptotic population growth rate l, calculated from a projection matrix model as a descriptor of the population dynamics, we analyze published data of 49 species of birds to determine how l is influenced by variation in different demographic traits. Across species, the mean elasticity of the adult survival rate was significantly larger than the mean elasticity of the fecundity rate. The contribution of the fecundity rate to the population growth rate increased with increasing clutch size and decreasing adult survival rate, while the greatest contribution of adult survival rate occurred among long-lived species that matured late and laid few eggs. This represents a continuum from ''highly reproductive species'' at one end to ''survivor species'' at the other end. In addition, a high contribution of adult survival rate was found in some relatively long-lived species with early age at maturity (and a large clutch size) which was assumed to represent a bet-hedging strategy, i.e., producing a large number of offspring in some occasional good years. In a retrospective analysis, interspecific differences in the effects of actual temporal variation in adult survival rate and fecundity rate on the variability of l were analyzed. These effects are expected to be large when the variance or the sensitivity of the trait is large. Because there was a negative relationship among species, both for the adult survival rate and the fecundity rate between the variability and the sensitivity of the trait, contribution of a trait to the variance in l decreased with sensitivity. Similarly, within species, less temporal variation was found in traits with high elasticities than in traits with less contribution to l. In some species, covariance among matrix elements also influenced the contribution of a demographic trait to l. Monitoring schemes of bird demography should be designed in such a way that temporal variances and covariances among demographic traits can be estimated. Further- more, it is important in such schemes to include data from a combination of traits that either have large sensitivities or high temporal variation.

Avian life history variation and contribution of demographic traits to the population growth rate

The continued growth of human populations and of per capita consumption have resulted in unsustainable exploitation of Earth’s biological diversity, exacerbated by climate change, ocean acidification, and other anthropogenic environmental impacts. We argue that effective conservation of biodiversity is essential for human survival and the maintenance of ecosystem processes. Despite some conservation successes (especially at local scales) and increasing public and government interest in living sustainably, biodiversity continues to decline. Moving beyond 2010, successful conservation approaches need to be reinforced and adequately financed. In addition, however, more radical changes are required that recognize biodiversity as a global public good, that integrate biodiversity conservation into policies and decision frameworks for resource production and consumption, and that focus on wider institutional and societal changes to enable more effective implementation of policy.

https://science.sciencemag.org/content/sci/329/5997/1298.full.pdf

Biodiversity conservation: challenges beyond 2010.

Although the uses and merits of terrestrial insects as indicators have been extensively discussed, there is a lack of clear definition, goal directedness and hypothesis testing in studies in the field. In an attempt to redress some of these issues and outline an approach for further studies, three categories of terrestrial insect indicators, corresponding to differences in their application, are proposed, i.e. environmental, ecological and biodiversity indicators. The procedures in terrestrial insect bioindicator studies should start with a clear definition of the study objectives and proposed use of the bioindicator, as well as with a consideration of the scale at which the study is to be carried out. Bioindication studies are conducted at a variety of spatial and temporal scales within the context of earth-system processes, but the objectives of the study will largely determine the scale at which it would be optimally conducted. There is a tendency for studies to be conducted below their space-time scaling functions, giving them apparent predictability. The selection of potential indicator taxa or groups is then based on a priori suitability criteria, the identification of predictive relationships between the indicator and environmental variables and, most importantly, the development and testing of hypotheses according to the correlative patterns found. Finally, recommendations for the use of the indicator in monitoring should be made. Although advocating rigorous, long-term protocols to identify indicators may presently be questionable in the face of the urgency with which conservation decisions have to be made, this approach is critical if bioindicators are to be used with any measurable degree of confidence.

The selection, testing and application of terrestrial insects as bioindicators

Arthropods, the most diverse component of terrestrial ecosystems, occupy a tremendous variety of functional niches and microhabitats across a wide array of spatial and temporal scales. We propose that conservation biologists should take advantage of terrestrial arthropod diversity as a rich data source for conservation planning and management. For reserve selection and design, documentation of the microgeography of selected arthropod taxa can delineate distinct biogeographic zones, areas of endemism, community types, and centers of evolutionary radiation to improve the spatial resolution of conservation planning. For management of natural areas, monitoring of terrestrial arthropod indicators can provide early warnings of ecological changes, and can be used to assay the effects of further fragmentation on natural areas that no longer support vertebrate indicator species. Many arthropod indicators respond to environmental changes more rapidly than do vertebrate indicators, which may exhibit population responses that do not become evident until too late for proactive management. Not all arthropod taxa are equally effective as indicators for conservation planning, and the qualities of indicators can differ for purposes of inventory versus monitoring. Assemblages of arthropod taxa used as biogeographic probes in inventories should exhibit relatively high species diversity, high endemism, and encompass the geographic range of interest. For monitoring purposes, indicator assemblages should exhibit varying sensitivity to environmental perturbations and a diversity of life-history and ecological preferences.



Resumen: Los artropodos, el componente mas diverso de los ecosistemas terrestres, ocupa una tremenda variedad de nichos funcionales y microhabitats a lo largo de una amplio espectro de escalas espaciales y temporales. Nosotros proponemos que los biologos de conservacion deberian aprovechar la diversidad de los atropodos terrestres como una rica fuente para el planeamiento y manejo conservacionista. La documentacion de la microgeografia de ciertos taxones de artropodos puede delinear zonas biogeograficas precisas, areas de endemismo, tipos de comunidades, y centros de radiacion evolutiva para mejorar la resolucion espacial en el planeamiento conservacionista destinado a la seleccion y diseno de reservas. En cuanto al manejo de areas naturales, el monitoreo de artropodos terrestres puede proveer de avisos tempranos sobre cambios ecologicos y puede ser usado para investigar los efectos de la fragmentacion subsecuente de areas naturales que ya no mantienen especies de vertebrados indicadoras. Muchos artropodos indicadores responden a los cambios hambientales mas rapidamente que vertebrados indicadores, los cuales pueden exhibir respuestas poblacionales que solo se hacen evidentes cuando ya es muy tarde para el manejo proteccionista. No todos los taxones de artropodos son igualmente efectivos como indicadores para el planeamiento conservacionista, y las calidades de los indicadores pueden variar dependiendo si su uso es con fines de inventario o de monitoreo. Las asociaciones de artropodos usados como sondas en inventarios deberian exhibir diversidades especificas relativamente altas, alto endemismo y deberian abarcar el rango geografico de interes. Si son usados con propositos de monitoreo, las asociaciones de indicadores deberian exhibir diferentes sensibilidades a las perturbaciones ambientales, y diversidad en cuanto a historias de vida y preferencias ecologicas.

https://www.jstor.org/stable/pdfplus/2386811.pdf

Terrestrial Arthropod Assemblages: Their Use in Conservation Planning

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Connectivity Conservation: List of contributors

For the first time in Earth's long history, one species – Homo sapiens – completely dominates the globe. Over 6 billion people now inhabit the planet, and that number is growing at an alarming rate. In sharp contrast to previous eras, we drive, fly, telephone, and e-communicate from even the most remote regions of Earth. With the aid of technology, no significant segment of our population is truly isolated. Today, it is possible to make a cell phone call from the Serengeti, or live “off the grid” from in-holdings within the midst of national forests or wilderness areas in North America. With the notable exception of weedy species that thrive amidst the disturbances we create, predictably, the more “connected” we become, non-human life with which we share this planet becomes increasingly disconnected. The vast reach of humans and the resulting parcelization of natural landscapes are of major concern to conservation scientists. Indeed, horror stories about habitat fragmentation appear in every book about conservation biology, make appearances in high-school textbooks, and are featured regularly in our leading newspapers and magazines. And conservation biologists are not alone in their concern about massive habitat destruction and fragmentation. Members of the public also have been inspired to promote special efforts for connecting landscapes in our increasingly dissected world. While the vision of connected landscapes may be compelling, the practice of preventing fragmentation and conserving connectivity is not a simple matter.

Connectivity Conservation: Connectivity conservation: maintaining connections for nature

Researchers have recently argued that ecological factors, especially high levels of cub predation, are more important than genetic impoverishment in limiting wild populations of the endangered cheetah ( Acino- nyx jubatus ). Despite considerable controversy, however, the forces actually driving cheetah population dy- namics remain unclear. We used a combination of demographic techniques to investigate how variation in survival and reproduction might influence the population persistence of wild cheetahs. We parameterized our models using detailed demographic data from recently published, long-term ecological projects on cheetahs of the Serengeti. Results suggest that the influence of juvenile survivorship on population growth rate is rela- tively small compared to the large effects of adult survivorship. This result is consistent across a range of vital rates and is robust to deviations due to sampling error and environmental variability. These conclusions cast a new light on the current cheetah controversy and, more generally, counsel caution in the interpretation of ecological data for conservation and management.

/pdf/new-insights-on-cheetah-conservation-through-demographic-1u0xbwmtsn.pdf

New Insights on Cheetah Conservation through Demographic Modeling

It is thought that genetic variation can affect the persistence of a population through its influence on disease susceptibility. We assessed genome-wide genetic variation, variation at a locus involved in the immune system, and acceptance or rejection of skin grafts in three natural populations of the pocket gopher (Thomomys bottae). Multilocus DNA fingerprints confirmed previous allozyme data, revealing high levels of variation among Hastings Reserve pocket gophers and almost complete within-population identity for individuals from the two Patricks Point populations (Patricks J and Patricks F), although Patricks J animals were dissimilar to animals from Patricks F despite their proximity. Individuals from the high-variation population consistently rejected within-population reciprocal skin grafts, whereas Patricks J and Patricks F individuals accepted within-population grafts. Patricks J and Patricks F individuals were found to be immunocompetent, however, as revealed by the ability of all individuals to reject between-population grafts, including those that previously accepted within-population grafts. A DNA heteroduplex analysis was then used to directly characterize variability at DQα, a locus of the immune system’s major histocompatability complex. Both populations low in genetic variation were fixed for unique DQα alleles, whereas observed heterozygosity in the Hastings population was 0.43, ascribable to at least three unique alleles. These data are in accord with previous cheetah skin-graft results and confirm that skin grafts can be used to assess genetic similarity. We suggest that although many animal populations can persist with extremely low levels of genetic variation in the wild, such populations may be at a greater risk of extinction from particular pathogens because of their genetic uniformity.



Se piensa que la variacion genetica puede afectar la persistencia de una poblacion por su influencia en la susceptibilidad a enfermedades. Esto punto de vista ha sido presentado en forma prominente a traves de varios estudios interesantes, aunque controvertidos y la aceptacion o rechazo de injertos de piel en tres poblaciones del topo Tomomys bottae. Huellas digitales del ADN multilocus revelaron un alto nivel de variacion entre los topos de la Reserva Hastings, e identidad intrapoblacional casi completa para los individuos de dos poblaciones de Patricks Point (Patricks J y Patricks F) confirmando previos datos de alozimas, aunque, a pesar de su proximidad los animales Patricks J eran diferentes a los Patricks F. Individuos de las poblaciones con alta variacion rechazaron en forma consistente injertos de piel reciprocos dentro de la poblacion mientras que individuos Patricks J y Patricks F aceptaron injertos dentro de la poblacion, se encontro que individuos Patricks J y Patricks F eran inmunocompetentes, a pesar de lo revelado por la habilidad de todos los individuos para rechazar injertos entre poblaciones, incluso aquellos que aceptaban injertos dentro de la poblacion. Analisis de ADN heteroduplex fue usado para caracterizar directamente la variabilidad de el locus DQα del Complejo Mayor de Histocompatibilidad (CMH). Las poblaciones con baja variacion genetica fueron fijadas como alelos DQαunicos, mientras que la heterocigosidad en la poblacion Hasting fue de 0.43, atribuible al menos a tres alelos unicos. Nuestros datos concuerdan con previos aunque controvertidos resultados de injertos de piel de chita y confirman que los injertos de piel pueden ser usados para evaluar similaridad genetica. Finalmente, sugerimos que aunque muchas poblaciones de animales pueden persistir con niveles bajos extremos de variacion genetica en estado salvaje, esas poblaciones pueden tener un mayor riesgo de extincion por patogenos especificos debido a su uniformidad genetica especialmente en lo referente al sistema immunologico.

https://www.jstor.org/stable/info/2387023

M. A. Sanjayan

Papers

Terrestrial Arthropod Assemblages: Their Use in Conservation Planning

Connectivity Conservation: List of contributors

Connectivity Conservation: Connectivity conservation: maintaining connections for nature

New Insights on Cheetah Conservation through Demographic Modeling

Genetic Variation and the Immune Response in Natural Populations of Pocket Gophers