Permanent Habitats Research Articles

Habitat type mediates equilibrium with climatic conditions in the distribution of Iberian diving beetles

ABSTRACTAim The contrasting habitat permanence over geological time‐scales of lotic and lentic habitats may impose different constraints on the dispersal ability of their macroinvertebrate populations, and ultimately on the degree of equilibrium with current climate. We aim to test for differences between species typical of either habitat type in their potential versus realized distributions as a surrogate measure of degree of climate equilibrium, both in refuges and more recently deglaciated areas.Location Western Europe.Methods We focus on 99 Iberian diving beetles (family Dytiscidae). A multidimensional envelope procedure was used to estimate their potential distributions, which were projected for different spatial scales. At the continental scale we calculated the percentage of countries with climatically suitable conditions for each species over those actually occupied (range filling). At the regional scale, we estimated realized distributions using: (1) convex hull polygons for Sweden and the Iberian Peninsula; and (2) generalized linear models for the Iberian Peninsula.Results In the Iberian Peninsula, differences in the degree of equilibrium with climatic conditions between lotic and lentic species were few, if any. However, at the continental scale we found significant differences, with lentic species closer to equilibrium than lotic species. In the recently deglaciated area (Sweden) the subset of species with ranges wide enough to encompass Iberia and Scandinavia were mostly lentic, and all were closer to climatic equilibrium without significant differences between habitat types.Main conclusions Our results show that, at continental scales, climate equilibrium is not concordant between the habitat types across western Europe. We hypothesize that: (1) the differences between refuge areas in dispersal ability are erased probably due to long‐term climatic stability, allowing enough time to reach equilibrium, and (2) the species with wide geographical ranges able to recolonize recently deglaciated areas should have the highest dispersal abilities, and are closer to climatic equilibrium.

Reseña de Tesis Doctorales En Ornitología (curso 2010–11)

Esta entrega incluye los resumenes de algunas de las Tesis Doctorales defendidas en Espana en el curso 2010–2011 junto con otras no recogidas en resenas anteriores. Se ha seguido una ordenacion alfabetica por Universidades y, dentro de ellas, por ano y orden alfabetico del autor.The distribution pattern and abundance of species is the outcome of their ecology and of their evolutionary history, reflecting the influence of different ecological processes acting at different spatial scales. Large-scale distribution is mainly influenced by abiotic factors, fundamentally climatic ones, and this constitutes the species’ fundamental niche. On a smaller scale other factors such as resource availability, local climate or biotic interactions come into play, forming the realised niche, which is defined through the species’ habitat selection. This thesis is placed within this framework, applying conceptual and methodological advances of habitat selection and ecological niche theories and their effects on the study of population dynamics and distribution at different spatial scales of a steppe bird, the little bustard (Tetrax tetrax). Thus, the first chapter tackles the intermediate scales (landscape), showing that little bustard males included a larger than expected proportion of old and same-year fallows within their display sites relative to their availability. This indicates a significant preference for permanent and semi-permanent habitat types, which offer them both shelter and food. The selection pattern was constant between study years, indicating fidelity in habitat selection pattern. On the other hand, display sites were not spatially clumped. The relevance of food availability in the selection process was analysed in the next chapter, highlighting the existence of a higher abundance of large beetles within males’ territories than elsewhere in the surrounding landscape. Since large beetles constitute a relevant element of little bustard's diet during the breeding season, it can be concluded that males make a positive selection of areas holding valuable food resources to establish territories. The results of both previous chapters are discussed in terms of little bustard's mating system in the study population. The inclusion in the territories of areas with higher proportion of food resources or of particular habitat types that females could potentially use, could support the existence of real exploded or resource-based lek mating system (which is typical in other European populations). However, the fact that territories were not spatially aggregated suggests that, at least at the studied spatial scale, little bustards in this population may not form leks, for which clumped territories are an essential requirement. The fidelity in the selection of permanent and semi-permanent habitat types suggests that this preference may be related to some structural characteristics in the vegetation which are common to these substrates. This smaller scale (microhabitat) may allow measuring several parameters directly related to different ecological compromises. The results of the next chapter showed the existence of sexual segregation in microhabitat selection, which can be related to males and females’ different ecological constraints due to different life history traits. Thus, vegetation structure selected by females is determined by a compromise between the need for shelter and anti-predator surveillance. For its part, males’ selection was related mainly to the need of conspicuousness for courtship and territory defence. Accessibility to food resources seemed to be equally important for both sexes. Next chapter evaluates the influences of meteorological factors and land management on the oscillations and medium-term trends of two important little bustard populations. Both populations declined during 2001–2007, especially in Valdetorres (60%). Variation in habitat composition did not explain variation in the number of males. Both populations w

Mosquito breeding sources in Qalyubiya Governorate, Egypt

Water collections which may provide breeding habitats for mosquitoes in Qalyubiya Governorate were surveyed throughout the period from April 2009 to March 2011. Mosquito larvae were collected on monthly basis from 14 different breeding places in eight villages. A total of 1800 from 2821 sites (63.8%) were found positive for mosquitoes, including 312 canals, 271 pools, 191 unused wells, 166 rice fields, 142 irrigation channels, 130 ponds, 128 drainages, 115 catch basins, 85 irrigation basins, 82 ditches, 70 swamps, 66 temporary pools, 22 unused tires and 20 irrigation drainage tubes. Mosquito larvae were found in a variety of water collections including temporary, permanent, natural or man-made habitats. Permanent and semipermanent water collections were the main sites for mosquito breeding. Nine mosquito species were identified in the study area namely, Culex pipiens 64.7%, Culiseta longiareolata 13.5%, Cx. antennatus 8.8%, Aedes caspius 6.3%, Cx. vagans 2.5%, Cx. decens 1.9%, Cx. perexiguus 0.9%, Cx. univittatus 0.8% and Anopheles multicolor 0.6%. Simple and Multiple regression models showed that temperature, Ammonia and Nitrate were the best predictors for mosquito larval density (P = 0.0397), (P = 0.0241) and (P = 0.0040), respectively. The year-round presence of immature mosquitoes indicates that climatic conditions of the area are not limiting to the development of most prevailing mosquito species. Catch basins, unused wells and drainages are playing the major role in mosquito problem in Qalyubiya Governorate.

Hydrogeology of Wadi Wurayah, United Arab Emirates, and its importance for biodiversity and local communities

Wadi Wurayah, in the Emirate of Fujairah, United Arab Emirates, lies within the Hajar Mountain range by the Gulf of Oman. The climate of the area is influenced by climatic events originating in Africa, Eastern Europe-Siberia, and the Indian and Pacific oceans. Rainfall provides 18.7 hm3 water annually, with an average of 2.24 hm3 as runoff. Recharge from rainfall to the mountain ophiolite complex creates a unique hydrogeological system with permanent freshwater habitats that support a biodiversity unique in the country and the world. The freshwater habitats host, amongst others, two species of amphibians, one fish species and aquatic insect species new to science. Spring waters classified as magnesium bicarbonate, slightly alkaline, with temperatures from 22 to 28°C and an average pH of 8.3, meet physico-chemical standards for drinking and bottled water, but do not meet the bacteriological standards near places frequented by tourists. An active management of the human pressure on the whole wadi ecosystem is urgently needed. Editor D. Koutsoyiannis; Guest editor M.C. Acreman Citation Tourenq, C., et al., 2011. Hydrogeology of Wadi Wurayah, United Arab Emirates, and its importance for biodiversity and local communities. Hydrological Sciences Journal, 56 (8), 1407–1422.

Anuran amphibians' diversity in a northwestern area of the Brazilian Pantanal

In the Pantanal, the largest continuous floodplain in the world, the diversity and distribution of anuran amphibians vary in and across distinct subregions and distinct habitats occurring along inundation gradients. Permanent and natural aquatic habitats are relatively scarce in the Pantanal, and occurrence of temporary aquatic habitats varies seasonally, depending on rains. We here present results of evaluations of anuran's species richness and abundance in a seasonally flooded area in the northwestern section of the Pantanal (Fazenda Baía de Pedra, Cáceres municipality, state of Mato Grosso, Brazil), comparing values obtained in 10 plots systematically distributed over 5 km² with those obtained in additional aquatic plots in the study area. Data were obtained in five field trips, from February 2008 to March 2009. In addition to the plots, 36 water bodies (20 permanent and 16 temporary) were also sampled for the presence of anurans. In total, 3,983 individuals from 34 anuran species distributed in five families were recorded: Hylidae (14 species), Leptodactylidae (8), Leiuperidae (6), Microhylidae (4), and Bufonidae (2). Local richness represents 77.3% of the anuran diversity already recorded for the Brazilian Pantanal. The number of species recorded exclusively in systematically distributed terrestrial plots and in water bodies was 28 and 32, respectively. Sampling methods used at Fazenda Baía da Pedra were efficient in determining anuran richness, abundance, composition and distribution. Evaluations of anuran richness and abundance by using permanent sampling plots in the Pantanal may benefit from additional sampling sites, particularly permanent and temporary water bodies.

Reproductive strategy of the jellyfish Aurelia aurita (Cnidaria Scyphomedusae) in the Suez Canal and its migration between the Red Sea and Mediterranean

The life history of the common jellyfish A. aurita (Linnaeus) in the Suez Canal was investigated by monthly sampling over a 28 month period from September 2006 to December 2008. Young medusae of 2–3 cm diameter appeared during February/March. Growth was rapid. Some specimens of this cohort reached 16 cm and spawned by March/May and then decreased in size or died. Others reached a maximal size of 10 cm by September, after which spawning took place. A few mature individuals remained after spawning in the next year but decreased in size. Release of ephyrae seems to be induced by a lowering of ambient environmental temperature to below 16°C, with peak of release occurring in December–February. A drop in temperature may be the primary cue for strobilation in the Suez Canal. A. aurita seems to be an immigrant plankter to the Suez Canal, and much interest was focused on determining from which end of the canal these organisms were invading the opposite sea. However, the canal itself, along with its lakes, should also be considered as a substantial permanent habitat in its own right. The canal cannot be considered only as a funnel or corridor through which animals pass like ships from one sea to the other. A. aurita appears to enter the Suez Canal from the south via water currents; to do so it needs to be carried over a distance of 20 km along the canal from the Gulf of Suez into the Bitter Lakes, then pass across the Bitter Lakes before being carried a further 12 km along the canal into Lake Timsah. Transport of A. aurita southward along the canal from the Mediterranean is unlikely to take place during most seasons of the year because it would require transport against the dominant-water flow; it is possible only during a brief period (July–September) of reversed flow. Because the main part of the 80 km from the Red Sea is canalized, passive transport of A. aurita by water currents from the north could occur within a week during the brief period of reversed flow even at the low speed of 0.5 km hour−1. Moreover, conditions (barriers, obstacles and/or links) along the migratory route of the Suez Canal, in either direction, are likely to determine the success of passive transport of A. aurita.

Estimates of Carrington-class solar particle event radiation exposures on Mars

Radiation exposure estimates for crew members on the surface of Mars are made for solar particle event proton radiation environments comparable to the Carrington event of 1859. We assume that the proton energy distributions for these Carrington-type events are similar to those measured for other, more recent large events. The fluence levels of these hypothetical events are normalized to the value for the Carrington event, as reported from measurements in ice core data. In this work, we use the BRYNTRN radiation transport code, originally developed at NASA Langley Research Center, and the Computerized Anatomical Male and Female human geometry models to estimate exposures for aluminum shield areal densities similar to those provided by a spacesuit, a surface lander, and a permanent habitat located at various altitudes in the Mars atmosphere. Comparisons of the predicted organ exposures with current NASA Permissible Exposure Limits are made.

A Phylogenetic Analysis of Pygmy Perches (Teleostei: Percichthyidae) with an Assessment of the Major Historical Influences on Aquatic Biogeography in Southern Australia

The biogeography of southern Australia is characterized by a repeated pattern of relatedness between the biota of southwestern and southeastern Australia. Both areas possess a temperate climate but are separated by a vast arid region, currently lacking permanent freshwater habitats, which has become increasingly drier since about 15 Ma. Aquatic organisms have thus potentially remained isolated for a considerable time. Pygmy perches (Nannatherina and Nannoperca, Percichthyidae) provide an excellent scenario for investigating biogeographic relationships between southwestern and southeastern regions as multiple species occur on either side of Australia. This allows us to potentially differentiate between "Multiple Invasion" and "Endemic Speciation," the two major hypotheses proposed to account for current distributions. The first suggests that multiple east-west movements have occurred, whereas the second suggests a single east-west split, with current biodiversity in each region being reciprocally monophyletic. Systematic relationships within this group were investigated with the mitochondrial cytochrome b gene; nuclear intron and exon sequences from S7, RAG1, and RAG2; and 53 allozyme loci. Our data supported the hypothesis of multiple movements across southern Australia based on a consistent lack of support for reciprocal monophyly of eastern and western species. This study appears to be the first example of an animal group displaying clear multiple east-west movement in southern Australia, as all other aquatic and terrestrial fauna previously examined displayed a single east-west split. Despite a high degree of sympatry within each region, the only evidence for hybridization was found between Nannoperca australis and N. obscura, with the latter having its mitochondrial genome completely replaced by that of N. australis, with no evidence for nuclear introgression. This is one of only a few confirmed examples of complete replacement of the mitochondrial genome in one species with that of another. Cryptic differentiation was also evident within the two most widespread species, N. australis and N. vittata, indicating that these likely consist of multiple species. We also highlight the need for multiple molecular markers with different strengths in order to obtain a more robust phylogeny, despite problems resulting from potential incongruences between data sets.

Larval habitat segregation between the molecular forms of the mosquito Anopheles gambiae in a rice field area of Burkina Faso, West Africa

In West Africa, lineage splitting between the M and S molecular forms of the major Afro-tropical malaria mosquito, Anopheles gambiae (Diptera: Culicidae), is thought to be driven by ecological divergence, occurring mainly at the larval stage. Here, we present evidence for habitat segregation between the two molecular forms in and around irrigated rice fields located within the humid savannahs of western Burkina Faso. Longitudinal sampling of adult mosquitoes emerging from a range of breeding sites distributed along a transect extending from the heart of the rice field area into the surrounding savannah was conducted from June to November 2009. Analysis revealed that the two molecular forms and their sibling species Anopheles arabiensis are not randomly distributed in the area. A major ecological gradient was extracted in relation to the perimeter of the rice fields. The M form was associated with larger breeding sites mostly consisting of rice paddies, whereas the S form and An. arabiensis were found to depend upon temporary, rain-filled breeding sites. These results support hypotheses about larval habitat segregation and confirm the suggestion that the forms have different larval habitat requirements. Segregation appears to be clearly linked to anthropogenic permanent habitats and the community structure they support.

A longitudinal study on Anopheles mosquito larval abundance in distinct geographical and environmental settings in western Kenya

BackgroundAs the ecology of mosquito larvae can be complex there is need to develop a rational framework for undertaking larval ecological studies. Local environmental characteristics, such as altitude, climate and land use, can significantly impact on phenology and population dynamics of mosquito larvae, and indirectly affect the dynamics of mosquito-borne diseases. The aim of this study was to assess the feasibility of implementing an integrated approach to larval source management under the distinct ecological settings.MethodsThe study was conducted in two highland villages and one village, at a lower altitude, in the Lake Victoria basin, where malaria is endemic and transmitted by the same Anopheles mosquito species. In each village the stability of mosquito larval habitats was classified as either temporary or permanent. The productivity of these habitat types was quantified by carrying out weekly larval sampling using a standard dipping method for a period of two years. During sampling the physical characteristic of the larval habitat, including the vegetation cover were noted. Ambient temperature, rainfall and relative humidity were recorded on a 21 × Micro-datalogger in each study site.ResultsAnopheles gambiae sensu lato larvae were found in all study sites. Anopheles arabiensis was more abundant (93%) in Nyalenda (Lake Victoria basin) and Fort Ternan (highland area; 71%). In Lunyerere (highland area), An. gambiae sensu stricto comprised 93% of the total An. gambiae s.l. larvae. Larvae of An. gambiae s.l. mosquitoes were present in both temporary and permanent habitats with monthly variations dependent on rainfall intensity and location. Anopheles larvae were more likely to be found in man-made as opposed to natural habitats. Grassy habitats were preferred and were, therefore, more productive of Anopheles larvae compared to other habitat types. Weekly rainfall intensity led to an increase or decrease in mosquito larval abundance depending on the location.ConclusionThe majority of mosquito breeding habitats were man made in all sites. Both temporary and permanent habitats were suitable for An. gambiae breeding. In Fort Ternan temporary sites were favoured for mosquito breeding above permanent sites. Significant differences in larval abundance were found depending on weekly rainfall intensity. Larval source management programmes should target permanent and temporary habitats equally and work closely with land and home owners as a majority of the breeding habitats are man made.

Living in Space: Cultural and Social Dynamics, Opportunities, and Challenges in Permanent Space Habitats

This article reviews the recent book of the Aerospace Technology Working Group, Living in Space, from an anthropological (holistic social science) perspective. This perspective is used as a springboard for both a discussion of the future, and for a critique of, astrosociology—a field broadly defined to include the range of social sciences as applied to human behaviors in, and in interaction with, various space environments. The review sets a theoretical context with some basic principles of social science, familiar to anthropologists, that can be applied to space habitats, and examines Living in Space in this social science context looking at what it does, where it fits in the literature, and what views of space and society it represents. It then seeks to sketch out how the future might go in astrosociology with appropriate funding and interest, along with a discussion of the prospects of the field.

Seasonal pattern of Batrachochytrium dendrobatidis infection and mortality in Lithobates areolatus: affirmation of Vredenburg's "10,000 zoospore rule".

To fully comprehend chytridiomycosis, the amphibian disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), it is essential to understand how Bd affects amphibians throughout their remarkable range of life histories. Crawfish Frogs (Lithobates areolatus) are a typical North American pond-breeding species that forms explosive spring breeding aggregations in seasonal and semipermanent wetlands. But unlike most species, when not breeding Crawfish Frogs usually live singly—in nearly total isolation from conspecifics—and obligately in burrows dug by crayfish. Crayfish burrows penetrate the water table, and therefore offer Crawfish Frogs a second, permanent aquatic habitat when not breeding. Over the course of two years we sampled for the presence of Bd in Crawfish Frog adults. Sampling was conducted seasonally, as animals moved from post-winter emergence through breeding migrations, then back into upland burrow habitats. During our study, 53% of Crawfish Frog breeding adults tested positive for Bd in at least one sample; 27% entered breeding wetlands Bd positive; 46% exited wetlands Bd positive. Five emigrating Crawfish Frogs (12%) developed chytridiomycosis and died. In contrast, all 25 adult frogs sampled while occupying upland crayfish burrows during the summer tested Bd negative. One percent of postmetamorphic juveniles sampled were Bd positive. Zoospore equivalents/swab ranged from 0.8 to 24,436; five out of eight frogs with zoospore equivalents near or >10,000 are known to have died. In summary, Bd infection rates in Crawfish Frog populations ratchet up from near zero during the summer to over 25% following overwintering; rates then nearly double again during and just after breeding—when mortality occurs—before the infection wanes during the summer. Bd-negative postmetamorphic juveniles may not be exposed again to this pathogen until they take up residence in crayfish burrows, or until their first breeding, some years later.

Are grasslands important habitats for soil microarthropod conservation?

Biodiversity has been a focal aim of environmental protection since the Rio conference, but only with the beginning of the new millennium did soil biodiversity become an important aspect of international policy. Edaphic fauna play a key role in many soil functions, such as organic matter decomposition, humus formation and nutrient element cycling; moreover, affect the porosity, aeration, infiltration and distribution of organic matter in soil horizons, modifying soil structure and improving its fertility. The ecosystem services provided by soil animals are becoming progressively lost due to agricultural practice intensification, which causes a reduction in both abundance and taxonomic diversity of soil communities. In the present study, a permanent grassland habitat was studied in order to evaluate its potential as a soil biodiversity reservoir in agroecosystems. Grassland samples were compared with samples from a semi-natural woodland area and an arable land site. Microarthropod abundances, Acari/Collembola ratio (A/C), Shannon diversity index (H′) and evenness index (E) were calculated. QBS-ar index was used in order to evaluate soil biological quality. Microarthropod communities of the three land use typologies differed in both the observed groups and their abundance. Steady soil taxa characterized both woodland and grassland soils, whereas their abundances were significantly higher in woodland soil. Taxon diversity and soil biological quality in the grasslands did not differ from the woodland samples. The microarthropod community in the arable land showed a reduction both in taxa numbers and soil biological quality compared with the other sites. Soil biological quality and edaphic community composition highlighted the importance of grassland habitats in the protection of soil biodiversity.

Antipredator responses of two anurans towards native and exotic predators

AbstractWhen faced with the risk of predation, tadpoles of many amphibian species are known to modify their phenotype. In this work we studied the effect of an exotic species, the red swamp crayfish (Procambarus clarkii), on the phenotype of two species of amphibians with different reproduction habitats: the Iberian painted frog, Discoglossus galganoi, that normally reproduces in temporary water bodies and the common toad, Bufo bufo, that reproduces in permanent water bodies. The responses were compared with the ones shown in the presence of a native predator, dragonfly (Aeshnidae) larvae. Behaviour, growth and morphology of tadpoles were monitored in a factorial experiment with five treatments. Our results showed that only the permanent habitat species altered its behaviour and life-history traits in the presence of P. clarkii; however, this was mediated by chemical cues from consumed conspecifics. Antipredator responses of B. bufo towards the exotic crayfish were similar to the ones towards the native predator, while D. galganoi responded to the dragonfly larvae but not to P. clarkii. This may be the result of infrequent colonization events of temporary habitats by the crayfish. Therefore, the consequences of the introduction of P. clarkii might be more serious for D. galganoi and other species living in temporary habitats. Species breeding in permanent habitats, more prone to having generalized antipredator responses, may be relatively protected against this exotic crayfish although the effectiveness of these responses still needs to be tested.

Taxonomy, distribution and ecology of the Setose Yabby, Cherax setosus (Riek, 1951)

Although it occurs near one of Australia's largest cities, there is a remarkable lack of information on the Setose Yabby, Cherax setosus. The morphology of the species has never been thoroughly described, and basic information on its distribution and ecology is required. In this paper, we give a thorough redescription of the species and present data on its distribution, habitat and general biology. Cherax setosus is a medium-sized crayfish with a lowland, coastal distribution extending from just south of Taree to just north of Morisset in eastern New South Wales, a northeastsouthwest distance of approximately 150km. The species is rarely found in permanent aquatic habitats in the area, but builds extensive burrow networks in minor, ephemeral habitats such as gullies, roadside ditches, stump holes, swamps and pastures. Although it appears to be relatively common across its range, the species may be susceptible to impacts such as reproductive interference with the translocated crayfish C. destructor and predation on juveniles by the introduced plague minnow, Gambusia holbrooki.

Lissotriton vulgaris paedomorphs in south-western Romania: a consequence of a human modified habitat?

A Lissotriton vulgaris paedomorph population was identified for the first time ever in south-western Romania. The newts inhabiting a permanent but artificial habitat, surrounded by agricultural fields.

Optimizing laboratory production of Strelkovimermis spiculatus (Nematoda: Mermithidae) with a discussion of potential release strategies for mosquito biological control

We assessed Strelkovimermis spiculatus preparasite (J2) infectivity and postparasite (J4) production in rearing pans using a laboratory host, second-instar Aedes aegypti mosquitoes, and evaluated first the production efficiency by testing increasing J2 concentrations (preparasite:host ratios). At 10 000 host larvae/rearing pan, we obtained the maximum yield of J4s (3.50 g), number of J4s/larva (3.1), and parasitism frequency (94.9 ± 9.5%) at a 10:1 J2/larva ratio. This 10:1 ratio, however, resulted in a significantly male-skewed sex ratio, whereas at ratios between 4:1 and 7:1 females predominated and parasite frequencies were still acceptable. Next, postparasite-inoculation methods were compared under culture conditions reflecting two categories of mosquito habitat (permanently flooded or desiccated cultures). The J4s were left to develop into adults, mate, and oviposit in the substrate. The flooded-culture J2s hatched at week 3 and after 30 weeks gave a total production of 6.2 × 104 per pan. Maximum J2 yield in desiccated cultures occurred at the first flooding (5 weeks), but emergence continued through drying flooding cycles for 10 weeks, giving a total J2 production of 4.5 × 105 per pan. The J2s infected mosquito larvae under both conditions. S. spiculatus preparasites or postparasites would serve as mosquito bioregulatory agents in temporary or permanent mosquito habitats. Relevant strategies are discussed.

Study of Antioxidant Defense in Four Species of Perloidea (Insecta, Plecoptera)

The aim of the present work is to conduct a comparative study of oxidative states in the nymphs of four species of Plecoptera belonging to the superfamily Perloidea: Perla marginata (Panzer, 1799) (family Perlidae), Guadalgenus franzi (Aubert, 1963), Isoperla curtate Navás, 1924, and lsoperla grammatica (Poda, 1761) (family Perlodidae) in relation to their ecological and biological characteristics. For this, the activity of the following antioxidant enzymes was determined: superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione transferase (GST), and DT-diaphorase (DTD), together with lipid peroxidation. Glucose 6-phosphate dehydrogenase (G6PDH) was also determined. The four species studied were selected based on significant ecological and biological differences. The results obtained when studying different indicative parameters of the oxidative state of the nymph of different species showed that each has an important enzymatic antioxidant potential, and that differences among species are conditioned by the duration of the nymphal development period more than by whether they come from permanent or temporary habitats. Thus, Plecoptera, although traditionally considered as typical inhabitants of permanent waters, seem to have sufficient variability in physiological mechanisms, together with behavioral and ecological adaptations, to cope with potentially unfavorable conditions that may occur in temporary waters.

Conservation genetics of Butte County meadowfoam (Limnanthes floccosa ssp. californica Arroyo), an endangered vernal pool endemic

The endangered annual plant Limnanthes floccosa ssp. californica Arroyo is restricted to vernal pools in Butte County, California. To identify populations with unique genetic resources, guide reintroduction efforts, and design seed collection scenarios for long-term ex situ seed storage we determined extant genetic diversity and structure by surveying 457 individuals from 21 distinct populations using nine polymorphic microsatellite markers. We found low within population genetic diversity: low allelic diversity (1.9 [0.06 SE] alleles/locus); low heterozygosity (Hobs = 0.10 ± 0.018, Hexp = 0.19 ± 0.015), and a high fixation index (0.556 ± 0.044). The number of polymorphic loci ranged between 11 and 89%. Bayesian ordination determined 20 distinct populations and we found high genetic structure among these (Fst = 0.65, P 5,000 extant plants per site. Our study confirms previous isozyme-based results and suggests that the loss of any population would represent a significant loss in the species’ genetic diversity. Recovery requires active restoration of existing populations and permanent habitat protection. We recommend close comparison of microhabitats of declining populations with genetically similar populations, to determine the potential for human assisted gene flow via seed movement to recover declining populations.

Interacting effects of habitat destruction and changing disturbance rates on biodiversity: Who is going to survive?

Changes in disturbance rates due to climate change may increase or decrease diversity, whereas permanent loss of habitat is generally believed to decrease diversity. It is, however, very likely that the effects of disturbances and habitat destruction interact. Understanding such combined effects is essential to predict the response of communities to global changes and in particular which functional types of species are most endangered. Using an individual-based spatially explicit community model, we investigate (1) whether diversity–disturbance curves alter when spatially uncorrelated or autocorrelated habitat destruction is added, and (2) which functional types of species are able to survive under these altered conditions. Model communities consisted of four functional types of species trading off between colonisation ability and competition strength. We found that habitat destruction may alter both height and shape of diversity-disturbance curves: maximum diversity at intermediate disturbance rates may shift to other disturbance rates or even split into two peaks giving rise to bimodal diversity–disturbance relationships with different sub-communities persisting at low and high disturbance rates. Diversity responded differentially depending on how the colonisation-competition trade-off was represented. Our results suggest that, for trade-offs in seed production rate, generally the best coloniser will better withstand the interacting effects of habitat destruction and changing disturbance rates; however, for trade-offs in mean dispersal distances, functional types characterized by intermediate abilities will perform best. We conclude that predictions of the impacts of changing disturbance rates on biodiversity depend on community structure and cannot be made without knowledge of concurrent permanent habitat destruction.