Local Populations Of Species Research Articles

Potential Invasiveness of Devil Firefish Pterois miles (Bennett 1828) in the Eastern Adriatic Sea

Abstract Devil firefish Pterois miles is an invasive alien species which has severely impacted biodiversity and ecological processes in invaded areas of the Mediterranean. In recent years, its presence has been documented in several countries of the Adriatic Sea. Based on the negative ecological and socio-economic impacts in other areas of the Mediterranean Sea, the potential invasiveness of devil firefish was analyzed for the coastal areas of the three eastern Adriatic countries (Albania, Croatia and Montenegro) using the Aquatic Species Invasiveness Screening Kit. Generally, based on the average value of the Basic Risk Assessment and the threshold used, the outcomes suggest that this species will be highly invasive in the eastern Adriatic countries. In addition, the results have shown that the most affected sector is represented by the local species populations and relative characteristics, while commercial sectors represent the least affected sector. However, considering that the negative impact of non-native species is not seen directly, the governments of these countries should address this issue as soon as possible.

Relevance of molecular systematics in insect pest management

Relevance of molecular systematics in insect pest management

NEW SPECIES OF MAMMALS IN KORGALZHYN STATE NATURE RESERVE

Theriological studies of the Teniz - Korgalzhyn region are covered rather sparsely in the literature and are fragmentary, since the Korgalzhyn Reserve mainly has an ornithological direction. The purpose of this article is to study the current state of the species composition of mammals of the Teniz-Korgalzhyn region and make the necessary additions to it. The research work was carried out for the period from 2016-2021. The authors of the article, based on the actual research conducted on the inventory of mammalian species in the reserve, prove the presence of local populations of species not previously noted on the territory of the reserve and include them in the inventory list of the theriofauna of the reserve. The material was collected on the territory of the Korgalzhyn State Nature Reserve and in its surroundings. Literary and intradepartmental data were also used. To include a new species in the list of local theriofauna and to distinguish individual visits of animals from the formation of a local population in the study area, 2 criteria were used: frequency and geography of encounters, and breeding of offspring. Of the 4 species new to the region, 2 species are native to Kazakhstan (Siberian roe deer, yellow gopher). Their presence in the region is insignificant and probably does not have a negative impact on the existing ecosystem of the region. The greatest concerns are caused by 2 acclimatizant species, namely the American mink, raccoon dog. Which are recognized as invasive species in Russia and Kazakhstan. The possibilities of the distribution and reproduction of these species in the territory they have developed and the possible impact on the native fauna of the region are also analyzed.

Lab-scale characterization and semi-field trials of Wolbachia Strain wAlbB in a Taiwan Wolbachia introgressed Ae. aegypti strain.

Dengue fever is one of the most severe viral diseases transmitted by Aedes mosquitoes, with traditional approaches of disease control proving insufficient to prevent significant disease burden. Release of Wolbachia-transinfected mosquitoes offers a promising alternative control methodologies; Wolbachia-transinfected female Aedes aegypti demonstrate reduced dengue virus transmission, whilst Wolbachia-transinfected males cause zygotic lethality when crossed with uninfected females, providing a method for suppressing mosquito populations. Although highly promising, the delicate nature of population control strategies and differences between local species populations means that controlled releases of Wolbachia-transinfected mosquitoes cannot be performed without extensive testing on specific local Ae. aegypti populations. In order to investigate the potential for using Wolbachia to suppress local Ae. aegypti populations in Taiwan, we performed lab-based and semi-field fitness trials. We first transinfected the Wolbachia strain wAlbB into a local Ae. aegypti population (wAlbB-Tw) and found no significant changes in lifespan, fecundity and fertility when compared to controls. In the laboratory, we found that as the proportion of released male mosquitoes carrying Wolbachia was increased, population suppression could reach up to 100%. Equivalent experiments in semi-field experiments found suppression rates of up to 70%. The release of different ratios of wAlbB-Tw males in the semi-field system provided an estimate of the optimal size of male releases. Our results indicate that wAlbB-Tw has significant potential for use in vector control strategies aimed at Ae. aegypti population suppression in Taiwan. Open field release trials are now necessary to confirm that wAlbB-Tw mediated suppression is feasible in natural environments.

Photovoltaic solar farms in California: can we have renewable electricity and our species, too?

Photovoltaic solar power generating facilities are proliferating rapidly in California and elsewhere. While this trend is welcomed for many reasons (e.g., reducing greenhouse gas emissions), these facilities also can have profound environmental impacts, particularly to local species populations. These impacts become more significant when species of conservation concern are affected. In the San Joaquin Desert region in central California, a number of conservation measures have been routinely implemented on solar facilities, and these measures have facilitated continued use of the facilities by a number of species of conservation concern. Some of the more significant measures include permeable security fences, vegetation management, movement corridors, avoiding critical features such as dens and burrows, and vehicle speed limits. Detailed studies have been conducted on San Joaquin kit foxes (Vulpes macrotis mutica) using solar facilities in the San Joaquin Desert. Demographic and ecological attributes of foxes are similar between foxes using the facilities and foxes on nearby reference sites, and values for foxes on solar sites are within the ranges of values for foxes reported from sites within core population areas. Facilitated by the conservation measures, kit foxes are using at least six facilities in the San Joaquin Desert as are a variety of other species of conservation concern. This successful model also potentially could be adapted to other ecosystems and applied to facilities in regions outside of the San Joaquin Desert, such as the Mojave Desert. Determining whether species in other regions can use photovoltaic solar facilities and identifying the most efficacious conservation measures will require time and testing, and these efforts would benefit from collaborative efforts among landowners, solar developers, natural resources agencies, researchers, and others. The San Joaquin Desert facilities and a recent demonstration facility in the Mojave Desert provide strong evidence that solar facilities can be constructed and operated in a manner that also accommodates continued use of the facilities by some species of conservation concern.

Area Not Geographic Isolation Mediates Biodiversity Responses of Alpine Refugia to Climate Change

Climate refugia, where local populations of species can persist through periods of unfavorable regional climate, play a key role in the maintenance of regional biodiversity during times of environmental change. However, the ability of refugia to buffer biodiversity change may be mediated by the landscape context of refugial habitats. Here, we examined how plant communities restricted to refugial sky islands of alpine tundra in the Colorado Rockies are changing in response to rapid climate change in the region (increased temperature, declining snowpack, and earlier snow melt-out) and if these biodiversity changes are mediated by the area or geographic isolation of the sky island. We resampled plant communities in 153 plots at seven sky islands distributed across the Colorado Rockies at two time points separated by 12 years (2007/2008–2019/2020) and found changes in taxonomic, phylogenetic, and functional diversity over time. Specifically, we found an increase in species richness, a trend toward increased phylogenetic diversity, a shift toward leaf traits associated with the stress-tolerant end of leaf economics spectrum (e.g., lower specific leaf area, higher leaf dry matter content), and a decrease in the functional dispersion of specific leaf area. Importantly, these changes were partially mediated by refugial area but not by geographic isolation, suggesting that dispersal from nearby areas of tundra does not play a strong role in mediating these changes, while site characteristics associated with a larger area (e.g., environmental heterogeneity, larger community size) may be relatively more important. Taken together, these results suggest that considering the landscape context (area and geographic isolation) of refugia may be critical for prioritizing the conservation of specific refugial sites that provide the most conservation value.

Small-scale population genetic structure of the sand bubbler crab Scopimera ryukyuensis in the Ryukyu Islands, Japan.

Generally, the gene flow of marine organisms is well maintained, but some local populations of coastal species are genetically differentiated even on a small scale (genetic patchiness). Small-scale isolation can be crucial for understanding genetic diversity within a species. The present study examined the population genetic structure of the sand bubbler crab Scopimera ryukyuensis, which is endemic to the Ryukyu Islands in the northwestern Pacific. A total of 52 haplotypes of mitochondrial cytochrome c oxidase subunit I were recovered from 197 specimens collected from four islands. The haplotype and nucleotide diversities were relatively high in thecentral Ryukyus (Amami-Oshima and Okinawa Islands) with some exceptions but were low at the southern edge of the geographical distribution of the species, i.e., the southern Ryukyus (Ishigaki and Iriomote Islands). Pairwise FST analysis suggested that the gene flow of S. ryukyuensis was largely restricted. The local populations of the species are differentiated among islands, except for stations on Ishigaki Island and a station on Iriomote Island. Moreover, a clear intra-island population genetic structure was observed within Amami-Oshima and Iriomote Islands, e.g., only 20 km between stations. Small-scale isolation among local populations may be a common tendency for coastal species in the Ryukyu Islands, considering the results of previous studies on corals.

Species insurance trumps spatial insurance in stabilizing biomass of a marine macroalgal metacommunity.

Because natural ecosystems are complex, it is difficult to predict how their variability scales across space and levels of organization. The species-insurance hypothesis predicts that asynchronous dynamics among species should reduce variability when biomass is aggregated either from local species populations to local multispecies communities, or from metapopulations to metacommunities. Similarly, the spatial-insurance hypothesis predicts that asynchronous spatial dynamics among either local populations or local communities should stabilize metapopulation biomass and metacommunity biomass, respectively. In combination, both species and spatial insurance reduce variation in metacommunity biomass over time, yet these insurances are rarely considered together in natural systems. We partitioned the extent that species insurance and spatial insurance reduced the annual variation in macroalgal biomass in a southern California kelp forest. We quantified variability and synchrony at two levels of organization (population and community) and two spatial scales (local plots and region) and quantified the strength of species and spatial insurance by comparing observed variability and synchrony in aggregate biomass to null models of independent species or spatial dynamics based on cyclic-shift permutation. Spatial insurance was weak, presumably because large-scale oceanographic processes in the study region led to high spatial synchrony at both population- and community-level biomass. Species insurance was stronger due to asynchronous dynamics among the metapopulations of a few common species. In particular, a regional decline in the dominant understory kelp species Pterygophora californica was compensated for by the rise of three subdominant species. These compensatory dynamics were associated with positive values of the Pacific Decadal Oscillation, indicating that differential species tolerances to warmer temperature and nutrient-poor conditions may underlie species insurance in this system. Our results illustrate how species insurance can stabilize aggregate community properties in natural ecosystems where environmental conditions vary over broad spatial scales.

Pine stumps act as hotspots for seedling regeneration after pine dieback in a mixed natural forest dominated by Chamaecyparis obtusa

AbstractOver the past few decades, rural forest ecosystems in Japan have experienced dynamic vegetation changes due to forest dieback and changes in land use, leading to the loss of local species populations and biodiversity. The aim of this study was to evaluate the importance of pine (Pinus densiflora) stumps and logs for tree seedling regeneration in a mixed natural forest in Kyoto Prefecture, Japan, that had previously experienced severe pine dieback, and to determine which factors most greatly affect seedling establishment. Seedlings of 17 tree species were recorded on pine stumps and logs in later stages of decay, among which Chamaecyparis obtusa and Rhododendron reticulatum were most dominant. Both of these species had a greater density on pine stumps than on logs or soil, despite stumps covering less than 0.5% of the study area. In addition, the seedling densities of both species were positively associated with moss cover on coarse woody debris, but negatively associated with wood pH. Brown rot in the sapwood and heartwood, which occurred more frequently in stumps than in logs, also positively associated with the seedling densities of both species. Predictive modelling showed that C. obtusa seedlings exhibited a stronger response to pH in stumps than in logs. Therefore, since brown‐rotted wood is acidic due to fungal decay activities, brown‐rotted pine stumps may present hotspots of C. obtusa seedling regeneration at the study site.

Spatial Distribution-Abundance Relationships in Juvenile (Age-0) Red Drum (Sciaenops Ocellatus) and Spotted Seatrout (Cynoscion Nebulosus). II: Influence of Major Disturbances

Local species populations that are more numerically abundant and occupy a greater proportion of the landscape relative to other species often recover more quickly (i.e., are more resilient) following local-scale environmental perturbations. In a companion study, we found that seatrout juvenile populations were distributed more broadly across Tampa Bay, Florida, and numerical abundance was generally much higher than those of similar-sized red drum, suggesting that spotted seatrout may also be generally more resilient to population declines than red drum. Following major population declines over a 12-year period (1996–2008), we found that larger juveniles of seatrout (51–100 mm standard length) simultaneously gained numerical abundance and broadened their spatial distribution generally within the next year. Population recovery in the same size of juvenile red drum generally took multiple years, and distribution and abundance increases were not always concurrent during the recovery period. Despite their overall higher abundance and broader spatial distribution, the smaller-sized juveniles of spotted seatrout (15–50 mm standard length (SL)) did not always recover more quickly from population declines compared with similar-sized red drum. Populations of the smaller-sized juveniles of both species often took multiple years to recover and showed non-concurrent increases in distribution and abundance during recovery. Despite their relatively narrow spatial distribution, juveniles of red drum may increase their overall resilience to local environmental perturbations by occupying multiple isolated patches across the Tampa Bay landscape. Monitoring dynamics of numerical abundance and spatial distribution may be helpful in gauging relative population resilience to facilitate overall management of these fishery populations.

Journal of Vegetation Science in 2015: journal growth, celebrations and awards

TheJournalofVegetationScience afteritsSilverJubileeThe Journal of Vegetation Science has now completed 25 yrsince the publication of the first volume in 1990 (P€artelet al.2014).Weareproudoftheachievementsofthejour-nal since its inception as the main international referencefor vegetation scientists reporting advances in plant com-munity ecology. We thank our authors, referees and edi-torsfortheircontinuingeffort.Theyear2014 wasparticularlysuccessfulforthe Journalof Vegetation Science. The journal has had an increasingimpact on the scientific community, which also meant anincreasedamountofworkfor oureditorsandreferees.Thetotal number of submitted papers was nearly 500, but theworkflow is now efficient and almost all papers are man-agedwithinareasonablyshorttime.ThankstofinancialsupportfromtheInternationalAsso-ciation for Vegetation Science(IAVS),a totalof1512 pageswere published in the Journal of Vegetation Science in 2014,well above our standard of 1200 pages. This allowed us tocut the queue of accepted papersandpublish a total of144papers.This year the Journal ofVegetation Sciencewillreturntoitsstandardpagenumber.Our recent innovation of publishing short commentar-iestoprovideadditionalideasorbroadercontexttospecificinterestingpaperspublishedinthejournalwillcontinuein2015. Nine research papers on different topics wereaddressed in commentaries in 2014. In addition to thesecommentary papers, we also published a Guest Editorialby a really distinguished vegetation scientist at a veryspecial period of his life: David W. Goodall on the occasionof his 100th birthday! The work done by David hasbeen fundamental for vegetation science, including hispioneering studies on randomized sampling protocols andstatistical ecology. He also introduced the now commonterm ‘ordination’. In his Editorial, David reflected on somefundamental steps from past vegetation science and alsoforesaw some future research needs, concluding that“coming generations in our science will certainly not beshortofproblemstoface!”(Goodall2014).In 2014 the Journal of Vegetation Science maintained andstrengthened its leading role in the field of plant commu-nity ecology. The number of citations of journal articlesincreased significantly, and this is well reflected in the lat-est Thomson-Reuters Impact Factor of 3.372. This is notonly the highest impact factor in the history of the JournalofVegetationScience,butitisalso itsfirstimpactfactorabove(well above) the threshold of three. With this increase, theimpact factor of the journal is now in the first quartile inthe Ecology category, as it was already for Plant Sciencesand Forestry. We are proud of this, and we want towork even harder to maintain and improve the journal’svisibility.Editors’Awardfor2014As every year, the Chief Editors of the Journal of VegetationScience makean award toa paper published inthe previousyear. As always, the decision was not easy, and there weremany papers on the candidate list. In the end, we decidedto give the Editors’ Award for 2014 to Alexander Correa-Metrio for the paper ‘Environmental determinism andneutrality in vegetation at millennial time scales’ (Correa-Metrio et al. 2014), a very elegant approach testing nicheand neutrality mechanisms in community assembly at amillennial scale. By using a pollen record spanning over86 000 yr,theystudiedtherelativecontributionofneutralprocesses and environmental determinism to the vegeta-tion pattern in the Central American lowlands. They con-cluded that neutral processes have certainly been relevantin assembling plant communities, but climate was themajor driver of vegetation dynamics during the late

Are trait‐based species rankings consistent across data sets and spatial scales?

AbstractQuestionsOne central assumption of trait screening approaches in comparative plant ecology, i.e. simultaneous measurement of traits on a large number of species or populations, is that the species level captures a major part of trait variation. The current development of large databases has led to a new screening approach that relies on the extraction of trait values from databases, rather than on measurement of traits in the field. We tested this assumption with the following questions: (1) is the magnitude of intra‐specific variability of co‐occurring species lower than inter‐specific variability for a given trait, in comparisons at different spatial scales; (2) is species hierarchy based on trait values conserved across different spatial scales and data sets (stable species hierarchy hypothesis); and (3) when we compare different traits, what is the more stable trait that is conserved across different spatial scales and data sets?MethodsWe combined approaches commonly used in functional ecology, i.e. experimental data, field observations and extraction of data from a global database, and analysed the magnitude of intra‐specific and inter‐specific trait variations for a large number of traits across contrasting environmental conditions for 18–39 (mostly) herbaceous species, according to the data set used.ResultsFor most traits, inter‐specific variability was higher than intra‐specific variability, and species ranking was conserved across different data sets and spatial scales. However, we also detected important differential responses in terms of intra‐specific trait variability, depending on the trait examined: SLA, LDMC, SM, seed N concentration and onset of flowering were more stable, whereas leaf chemical traits and RH were more flexible traits.ConclusionsOur study validated, for the species studied, the stable species hierarchy hypothesis in the case of several, but not all, widely used traits. The main conclusion is that the strength of the species signal is strong enough for some traits to allow values to be used from different data sets (experiments, databases) to characterize local populations of species: for SM, seed N concentration, RH, SLA and LDMC.

A review of flying fishes of the subgenus Hirundichthys (genus Hirundichthys, exocoetidae). 1. Oceanic species: H. speculiger, H. indicus sp. nova

A systematic revision of flying fishes of the subgenus Hirundichthys s.str was carried out based on a study of meristic and morphometric traits and characteristics of pigmentation of fishes from the local populations of species belonging to the subgenus. It is found out that the subgenus includes four species: oceanic H. speculiger from the Atlantic, Pacific and Indian Oceans, oceanic H. indicus sp.n. from the waters of the Indian Ocean, nerito-oceanic H. oxycephalus from the waters of the Indo-West Pacific and nerito-oceanic H. affinis from the Atlantic Ocean. The first part of the review focuses on two oceanic species with a large “mirror” on the pectoral fins: H. speculiger and H. indicus. A comparison of local populations showed that the species H. indicus is polytypic and consists of two subspecies. One of the subspecies—nominative H. indicus indicus—is distributed in the western and the central parts of the Indian Ocean and the other—H. indicus orientalis ssp.n.—in the Eastern Indian Ocean. Maps showing a geographical distribution of the species and the subspecies in the World Ocean are drawn up.

The influence of landscape context on the distribution of flightless mammals in exurban developments

Broad-acre subdivisions constitute an increasing form of residential development known as exurbia. Despite significant impacts on biodiversity, exurbia is critically understudied in Australia. Exurban developments are distributed non-uniformly around city margins and are typically clustered adjacent to desirable landscape elements, such as forests and water. Forested peninsulas are thus popular sites for exurban development. Developments on these relatively insular regions have the potential to reduce local populations of species with limited dispersal capabilities and an aversion to exurbia. Two exurban regions of Hobart, Tasmania, Australia, one a peninsula and one inland, were surveyed for flightless mammals using spotlight observations and a survey of landowners. The frequencies of mammals within exurbia were compared with their frequencies in wildlands and tested against life history traits. Within the exurbanised peninsula, there were disproportionately fewer individuals of species with large home range sizes. Overall, two very fecund species, including a threatened native bandicoot, Perameles gunnii, were more frequent in exurbia than in wildlands. We cannot conclude that any of female body mass, female home range size and fecundity can provide consistently strong predictions of the likelihood of negative or positive effects of urbanisation, but we can conclude that each of these variables can be predictive within particular regional and faunal contexts. We suggest that, until further information is gained, planners could use fecundity as a predictor of mammal survival in exurbia, except where the exurban area is isolated from other areas that contain native vegetation, in which case, female home range negatively predicts survival.

The role of infectious diseases in biological conservation

AbstractRecent increases in the magnitude and rate of environmental change, including habitat loss, climate change and overexploitation, have been directly linked to the global loss of biodiversity. Wildlife extinction rates are estimated to be 100–1000 times greater than the historical norm, and up to 50% of higher taxonomic groups are critically endangered. While many types of environmental changes threaten the survival of species all over the planet, infectious disease has rarely been cited as the primary cause of global species extinctions. There is substantial evidence, however, that diseases can greatly impact local species populations by causing temporary or permanent declines in abundance. More importantly, pathogens can interact with other driving factors, such as habitat loss, climate change, overexploitation, invasive species and environmental pollution to contribute to local and global extinctions. Regrettably, our current lack of knowledge about the diversity and abundance of pathogens in natural systems has made it difficult to establish the relative importance of disease as a significant driver of species extinction, and the context when this is most likely to occur. Here, we review the role of infectious diseases in biological conservation. We summarize existing knowledge of disease‐induced extinction at global and local scales and review the ecological and evolutionary forces that may facilitate disease‐mediated extinction risk. We suggest that while disease alone may currently threaten few species, pathogens may be a significant threat to already‐endangered species, especially when disease interacts with other drivers. We identify control strategies that may help reduce the negative effects of disease on wildlife and discuss the most critical challenges and future directions for the study of infectious diseases in the conservation sciences.

Phlebotomine sandflies (Diptera: Psychodidae) of the Atlantic forest in Recife, Pernambuco state, Brazil: the species coming to human bait, and their seasonal and monthly variations over a 2-year period

In a study of the phlebotomine sandflies (Diptera: Psychodidae) in a forest reserve in Recife, Pernambuco state, north-eastern Brazil, the sandflies landing on human bait between 1.00 and 1.42 h after sunset were collected weekly for 2 years. Although 10,287 sandflies of 10 Lutzomyia species were collected, almost all (96.5%) of the sandflies caught were Lu. umbratilis. This species and several others caught are potential vectors of some of the Leishmania parasites that cause human disease. The recorded landing rate for Lu. umbratilis peaked, at the high level of 333.3 flies/person-hour, during the collections made in May 2003.The relative rarity in the collections of males of some of the species caught probably indicates that these species do not lek on their bloodmeal sources. It is likely that the sizes of the local populations of species that are not very anthrophilic, such as Lu. flaviscutellata, are much larger than indicated by the collections made on human bait.

USING THE METABOLIC THEORY OF ECOLOGY TO PREDICT GLOBAL PATTERNS OF ABUNDANCE

EcologyVolume 85, Issue 7 p. 1800-1802 Forum: Metabolic Theory USING THE METABOLIC THEORY OF ECOLOGY TO PREDICT GLOBAL PATTERNS OF ABUNDANCE Michael Kaspari, Michael Kaspari Department of Zoology, University of Oklahoma, Norman, Oklahoma 73019-0235 USA E-mail: [email protected]Search for more papers by this author Michael Kaspari, Michael Kaspari Department of Zoology, University of Oklahoma, Norman, Oklahoma 73019-0235 USA E-mail: [email protected]Search for more papers by this author First published: 01 July 2004 https://doi.org/10.1890/03-0682Citations: 30 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume85, Issue7July 2004Pages 1800-1802 RelatedInformation

On spatiotemporal patchiness and the coexistence of five species of Chronogaster (Nematoda: Chronogasteridae) in a riparian wetland.

Spatiotemporal patchiness in the soil environment is thought to be crucial for the maintenance of soil biodiversity. It provides diverse microhabitats (allowing resource partitioning), and presents these in a complex mosaic, such that competitors may be spatially and temporally separated (promoting patch dynamics). The objective of our study was to assess the importance of patch dynamics for the maintenance of landscape-level nematode diversity. The spatiotemporal aggregation patterns in populations of five species of the bacterivorous genus Chronogaster were analyzed for a 0.7-ha riparian wetland, during four seasons, using geostatistical methods (spatiotemporal variograms, cross-correlograms, and log-normal kriging). We found that for the three most abundant species, aggregation was significant over distances of 13-39m, with intraspecific aggregation stronger than interspecific aggregation. In addition, species patterns appeared to be temporally dynamic: local population declines alternated with local blooms at different sites and seasons. One species was consistently present at the same few sites, but the other species showed gradual temporal decreases and increases at different locations in the wetland. Combining nematode patterns with information on soil resource distributions and Chronogaster ecology, indicated that both soil resource patchiness and repeated, but largely unpredictable, disturbances caused by local soil moisture fluctuations could promote landscape-level Chronogaster diversity by providing ample 'probability refuges.' Local species populations, reduced by competition, predation and drought, could recolonize patches either through the awakening of local dormant 'seed populations,' or through limited passive dispersal by wind, water, and phoresis. We suggest that the spatiotemporal Chronogaster data provide preliminary evidence for the importance of patch dynamics in maintaining soil nematode diversity.

Regional Dynamics and the Status of Amphibians

Increasing attention is being devoted to the dynamics of interacting local populations of species, especially the role of changes in incidence that affect regional persistence. The status of species in a regional context may be determined more by metapopulation dynamics than by purely demographic birth and death processes. The contrast between local and regional views of species' persistence is illustrated today by discussion of the status of amphibians. The amphibian fauna may provide an important indicator of the impact of anthropogenic disturbance to wetland ecosystems. We assessed the status of 11 amphibian species in southwestern Ontario, Canada, by estimating species richness, changes in presence and absence, and incidence at 97 ponds from 1992 to 1994. We detected a significant reduction in amphibian species richness in one of three regions. This loss of diversity relative to the historical species complement is a consequence of the land use history. We observed surprisingly high turnover of species at ponds, with increased incidence varying from 0.07 to 0.29 species per pond per year, and decreased incidence ranging from 0.16 to 0.30 species per pond per year. The incidence of common species across years included both declines (leopard frog, Rana pipiens) and increases (American toad, Bufo americanus). For eight relatively rare species, losses exceeded gains between 1992 and 1993, but this pattern was reversed between 1993 and 1994. Understanding environmental factors that determine the status of species will require an expanded, large—scale view of groups of populations (metapopulations) and their spatial dynamics.

Ecological theory and endangered species: ed P. Kareiva, Ecology, 75(3), 1994, pp 583–626

Broad-acre subdivisions constitute an increasing form of residential development known as exurbia. Despite significant impacts on biodiversity, exurbia is critically understudied in Australia. Exurban developments are distributed non-uniformly around city margins and are typically clustered adjacent to desirable landscape elements, such as forests and water. Forested peninsulas are thus popular sites for exurban development. Developments on these relatively insular regions have the potential to reduce local populations of species with limited dispersal capabilities and an aversion to exurbia. Two exurban regions of Hobart, Tasmania, Australia, one a peninsula and one inland, were surveyed for flightless mammals using spotlight observations and a survey of landowners. The frequencies of mammals within exurbia were compared with their frequencies in wildlands and tested against life history traits. Within the exurbanised peninsula, there were disproportionately fewer individuals of species with large home range sizes. Overall, two very fecund species, including a threatened native bandicoot, Perameles gunnii, were more frequent in exurbia than in wildlands. We cannot conclude that any of female body mass, female home range size and fecundity can provide consistently strong predictions of the likelihood of negative or positive effects of urbanisation, but we can conclude that each of these variables can be predictive within particular regional and faunal contexts. We suggest that, until further information is gained, planners could use fecundity as a predictor of mammal survival in exurbia, except where the exurban area is isolated from other areas that contain native vegetation, in which case, female home range negatively predicts survival.