Patch occupancy in the endangered butterfly Lycaena helle in a fragmented landscape: effects of habitat quality, patch size and isolation

While there is agreement that both habitat quality and habitat network characteristics (such as patch size and isolation) contribute to the occupancy of patches by any given species, the relative importance of these factors is under debate. This issue is of fundamental ecological importance, and moreover of special concern for conservation biologists aiming at preserving endangered species. Against this background we investigated patch occupancy in the violet copper Lycaena helle, one of the rarest butterfly species in Central Europe, in the Westerwald area (Rhineland-Palatinate, Western Germany). Occupied (n = 102) differed from vacant (n = 128) patches in altitude, size, connectivity, availability of wind shelter, in the abundance of the larval host-plant, in the abundance of a grass species indicating favorable habitat conditions and in the abundance of nitrophilous plants. Overall, patch occupancy was primarily determined by patch size, connectivity and the abundance of the larval host plant, while all other parameters of habitat quality were of subordinate importance. Therefore, our findings suggest that even for extremely sedentary species such as L. helle habitat networks are decisive and—next to the preservation of habitat quality—need to be an integral part of any conservation management for this species.     

Incorporating asymmetric movement costs into measures of habitat connectivity to assess impacts of hydrologic alteration to stream fishes

Aim

Hydrologic alterations are widespread in freshwater ecosystems worldwide and often detrimentally impact fish populations. Habitat suitability models are commonly used to assess these impacts, but these models frequently rely upon observed fish–habitat relationships rather than more mechanistic underpinnings. The aim of this study was to demonstrate how to incorporate swim performance into a measure of habitat connectivity at a fine scale, providing a method for assessing the availability of suitable habitat for stream fishes.

Location

We applied this technique to an endangered species, the Western Silvery Minnow Hybognathus argyritis, in the Milk River of southern Alberta, Canada. The Milk River is an augmented system, where a diversion in nearby St. Mary River augments flow by a factor >3 × (from 1–5 m³/s to 15–20 m³/s).

Methods

We used laboratory measured swim performance of Western Silvery Minnow to develop a movement cost function that was used in conjunction with a habitat suitability model to assess habitat availability via a recently developed graph‐theoretic metric, equivalent connected area (ECA).

Results

Stream augmentation altered not only habitat suitability but also habitat connectivity for this species. During augmentation, suitable habitat area declined by 81.3%. Changes in habitat connectivity were site dependent. Movement costs between habitat patches were lower during augmentation due to current‐assisted dispersal and increased distance to patches during natural flows from dried streambeds. When movement costs were incorporated into ECA, ECA decreased by 78.0% during augmentation.

Main conclusions

With changing climate and increasing anthropogenic impacts on aquatic ecosystems, understanding how freshwater fishes relate to their habitat is critical for appropriate management. In many cases, such as the Western Silvery Minnow, mitigating habitat suitability may not be sufficient, as species are unable to reach suitable habitat. The incorporation of swim performance into habitat connectivity assessments, as carried out here, can be easily adapted to other species and situations and can improve the understanding of impacts to stream fishes and increase the effectiveness of mitigation efforts.     

Species Distribution Modelling predicts habitat suitability and reduction of suitable habitat under future climatic scenario for Sclerophrys perreti: A critically endangered Nigerian endemic toad

Sclerophrys perreti is a critically endangered Nigerian native frog currently imperilled by human activities. A better understanding of its potential distribution and habitat suitability will aid in conservation; however, such knowledge is limited for S. perreti. Herein, we used a species distribution model (SDM) approach with all known occurrence data (n = 22) from our field surveys and primary literature, and environmental variable predictors (19 bioclimatic variables, elevation and land cover) to elucidate habitat suitability and impact of climate change on this species. The SDM showed that temperature and precipitation were the predictors of habitat suitability for S. perreti with precipitation seasonality as the strongest predictor of habitat suitability. The following variable also had a significant effect on habitat suitability: temperature seasonality, temperature annual range, precipitation of driest month, mean temperature of wettest quarter and isothermality. The model predicted current suitable habitat for S. perreti covering an area of 1,115 km². However, this habitat is predicted to experience 60% reduction by 2050 owing to changes in temperature and precipitation. SDM also showed that suitable habitat exists in south-eastern range of the inselberg with predicted low impact of climate change compared to other ranges. Therefore, this study recommends improved conservation measures through collaborations and stakeholder's meeting with local farmers for the management and protection of S. perreti.     

Effect of climate change in lizards of the genus Xenosaurus (Xenosauridae) based on projected changes in climatic suitability and climatic niche conservatism

Accelerated climate change represents a major threat to the health of the planet's biodiversity. Particularly, lizards of the genus Xenosaurus might be negatively affected by this phenomenon because several of its species have restricted distributions, low vagility, and preference for low temperatures. No study, however, has examined the climatic niche of the species of this genus and how their distribution might be influenced by different climate change scenarios. In this project, we used a maximum entropy approach to model the climatic niche of 10 species of the genus Xenosaurus under present and future suitable habitat, considering a climatic niche conservatism context. Therefore, we performed a similarity analysis of the climatic niche between each species of the genus Xenosaurus. Our results suggest that a substantial decrease in suitable habitat for all species will occur by 2070. Among the most affected species, X. tzacualtipantecus will not have suitable conditions according to its climatic niche requirements and X. phalaroanthereon will lose 85.75% of its current suitable area. On the other hand, we found low values of conservatism of the climatic niche among species. Given the limited capacity of dispersion and the habitat specificity of these lizards, it seems unlikely that fast changes would occur in the distribution of these species facing climate change. The low conservatism in climatic niche we found in Xenosaurus suggests that these species might have the capacity to adapt to the new environmental conditions originated by climate change.     

Diversity of medium and large mammals in the Loka Abaya National Park,southern Ethiopia

We evaluated the richness, diversity, and composition of the medium and large mammal community in the Loka Abaya National Park (LANP), southern Ethiopia, and how these parameters differ among four habitat types: wooded grassland, riverine forest, hilly scrubland and wetland, and between seasons. We recorded a total of 2,573 individual animals of 28 medium and large mammal species in the park. This included three globally threatened species: the endangered African wild dog (Lycaon pictus), the vulnerable Leopard (Panthera pardus), and Hippopotamus (Hippopothamus amphibius). Season had little effect on species richness, diversity, and composition both across and within habitat types. However, species richness across seasons was significantly different among the four habitat types, in the declining order of the following: wooded grassland > riverine forest > hilly scrubland > wetland. The strongest similarity in species composition, both across and within seasons, was found between wooded grassland and riverine forest. In terms of relative abundance, mammal assemblage of the wooded grassland and wetland habitats had more evenly distributed number of species with different relative abundance categories. Overall, Anubis Baboon (Papio anubis), Grivet Monkey (Chlorocebus aethiops), and Greater Kudu (Tragelephus strepsiceros) were the three most abundant species across habitat types. In conclusion, findings of our study reveal that LANP plays an important role in Ethiopia's mammal conservation. Our findings will serve as baseline information for managers of the park to make effective conservation decisions and as a baseline for researchers wishing to conduct related ecological studies.     

Floral functional structure,sexual phases,flower visitors and aspects of breeding system in <Emphasis Type="Italic">Roella ciliata</Emphasis> (Campanulaceae) in a fragmented habitat

Continued habitat destruction in lowland areas of the Western Cape, South Africa, due to urbanization has reduced Roella ciliata to a few isolated populations and it is unknown whether this endemic shrublet will persist. Here, we examine the reproductive biology of a small population of R. ciliata occurring in a residential nature reserve 30 km east of Cape Town to provide baseline information for future studies. Data were recorded on the functional structure of the flower, duration of the morphological gender phases, floral visitor profile and the relationship between breeding system and habitat. Observations revealed that this species possesses reproductive characteristics typical of Campanulaceae such as dichogamy, protandry and secondary pollen presentation via pollen collecting hairs. Floral longevity ranges between 1 and 3 days. Anthesis occurs in synchronicity at 0700 hours and individual flowers close between 0930 and 1500 hours daily. The staminate phase lasts between 2 and 29 h and is significantly influenced by the removal of pollen by floral visitors, while the pistillate phase lasts between 21 and 69 h. R. ciliata maintains a generalized, entomophilous pollination system although floral visitors are generally scarce. Despite some intraspecific variation, the pollen/ovule ratio indicates that R. ciliata has a facultatively autogamous breeding system, in contrast to its floral attributes which might favour xenogamy. This reproductive mechanism may ensure survival under these habitat conditions and could represent a shift from outcrossing to selfing at the cost of reducing genetic variation over time.     

Synergistic effects of habitat preference and gregarious behaviour on habitat use in coral reef cardinalfish

Spatial distributions of coral reef fish species are potentially determined by habitat preferences and behavioural interactions. However, the relative importance of these factors and whether or not behavioural interactions reinforce or disrupt habitat associations are poorly understood. This paper explores the degree to which habitat and social preferences explain the association that three common coral reef cardinalfish species (Zoramia leptacanthus, Archamia zosterophora and Cheilodipterus quinquelineatus; family Apogonidae) have with coral substrata at Lizard Island, Great Barrier Reef. At diurnal resting sites, species were strongly associated with branching corals, with 80–90% of each species inhabiting one branching coral species, Porites cylindrica. Species were also highly gregarious, forming large con-specific and hetero-specific aggregations in coral heads, potentially reinforcing habitat associations. Three-way choice experiments were conducted to test fishes habitat preferences for living coral over dead substrata, for particular coral species, and the influence of gregarious behaviour on these habitat choices. The strength of habitat preferences differed among species, with Z. leptacanthus preferring live coral and P. cylindrica, A. zosterophora preferring P. cylindrica, whether live or dead and C. quinquelineatus exhibiting no preferences. All species were attracted to conspecifics, and for C. quinquelineatus and A. zosterophora, conspecific attraction resulted in stronger preferences for live corals. Gregarious behaviour also increased C. quinquelineatus associations with P. cylindrica. The relative strength of social attraction versus habitat preferences was investigated by comparing fish habitat preferences in the presence and/or absence of conspecifics. The presence of conspecifics on non-preferred rubble habitat reduced each species association with live coral. This study’s results indicate that in the field, habitat preferences and conspecific attraction combine to reinforce the association between cardinalfishes and a narrow range of coral substrata.     

Sea level rise may increase extinction risk of a saltmarsh ontogenetic habitat specialist

Specialist species are more vulnerable to environmental change than generalist species. For species with ontogenetic niche shifts, specialization may occur at a particular life stage making those stages more susceptible to environmental change. In the salt marshes in the northeast U.S., accelerated sea level rise is shifting vegetation patterns from flood‐intolerant species such as Spartina patens to the flood‐tolerant Spartina alterniflora. We tested the potential impact of this change on the coffee bean snail, Melampus bidentatus, a numerically dominant benthic invertebrate with an ontogenetic niche shift. From a survey of eight marshes throughout the northeast U.S., small snails were found primarily in S. patens habitats, and large snails were found primarily in stunted S. alterniflora habitats. When transplanted into stunted S. alterniflora, small snails suffered significantly higher mortality relative to those in S. patens habitats; adult snail survivorship was similar between habitats. Because other habitats were not interchangeable with S. patens for young snails, these results suggest that Melampus is an ontogenetic specialist where young snails are habitat specialists and adult snails are habitat generalists. Temperature was significantly higher and relative humidity significantly lower in stunted S. alterniflora than in S. patens. These data suggest that thermal and desiccation stress restricted young snails to S. patens habitat, which has high stem density and a layer of thatch that protects snails from environmental stress. Other authors predict that if salt marshes in the northeast U.S. are unable to migrate landward, sea level rise will eliminate S. patens habitats. We suggest that if a salt marsh loses its S. patens habitats, it will also lose its coffee bean snails. Our results demonstrate the need to consider individual life stages when determining a species’ vulnerability to global change.     

Predicting the effects of climate change on population connectivity and genetic diversity of an imperiled freshwater mussel,Cumberlandia monodonta (Bivalvia: Margaritiferidae), in riverine systems

In the face of global climate change, organisms may respond to temperature increases by shifting their ranges poleward or to higher altitudes. However, the direction of range shifts in riverine systems is less clear. Because rivers are dendritic networks, there is only one dispersal route from any given location to another. Thus, range shifts are only possible if branches are connected by suitable habitat, and stream‐dwelling organisms can disperse through these branches. We used Cumberlandia monodonta (Bivalvia: Unionoida: Margaritiferidae) as a model species to investigate the effects of climate change on population connectivity because a majority of contemporary populations are panmictic. We combined ecological niche models (ENMs) with population genetic simulations to investigate the effects of climate change on population connectivity and genetic diversity of C. monodonta. The ENMs were constructed using bioclimatic and landscape data to project shifts in suitable habitat under future climate scenarios. We then used forward‐time simulations to project potential changes in genetic diversity and population connectivity based on these range shifts. ENM results under current conditions indicated long stretches of highly suitable habitat in rivers where C. monodonta persists; populations in the upper Mississippi River remain connected by suitable habitat that does not impede gene flow. Future climate scenarios projected northward and headwater‐ward range contraction and drastic declines in habitat suitability for most extant populations throughout the Mississippi River Basin. Simulations indicated that climate change would greatly reduce genetic diversity and connectivity across populations. Results suggest that a single, large population of C. monodonta will become further fragmented into smaller populations, each of which will be isolated and begin to differentiate genetically. Because C. monodonta is a widely distributed species and purely aquatic, our results suggest that persistence and connectivity of stream‐dwelling organisms will be significantly altered in response to future climate change.     

Reef‐coral refugia in a rapidly changing ocean

This study sought to identify climate‐change thermal‐stress refugia for reef corals in the Indian and Pacific Oceans. A species distribution modeling approach was used to identify refugia for 12 coral species that differed considerably in their local response to thermal stress. We hypothesized that the local response of coral species to thermal stress might be similarly reflected as a regional response to climate change. We assessed the contemporary geographic range of each species and determined their temperature and irradiance preferences using a k‐fold algorithm to randomly select training and evaluation sites. That information was applied to downscaled outputs of global climate models to predict where each species is likely to exist by the year 2100. Our model was run with and without a 1 °C capacity to adapt to the rising ocean temperature. The results show a positive exponential relationship between the current area of habitat that coral species occupy and the predicted area of habitat that they will occupy by 2100. There was considerable decoupling between scales of response, however, and with further ocean warming some ‘winners’ at local scales will likely become ‘losers’ at regional scales. We predicted that nine of the 12 species examined will lose 24–50% of their current habitat. Most reductions are predicted to occur between the latitudes 5–15°, in both hemispheres. Yet when we modeled a 1 °C capacity to adapt, two ubiquitous species, Acropora hyacinthus and Acropora digitifera, were predicted to retain much of their current habitat. By contrast, the thermally tolerant Porites lobata is expected to increase its current distribution by 14%, particularly southward along the east and west coasts of Australia. Five areas were identified as Indian Ocean refugia, and seven areas were identified as Pacific Ocean refugia for reef corals under climate change. All 12 of these reef‐coral refugia deserve high‐conservation status.     

Identifying refugia and corridors under climate change conditions for the Sichuan snub‐nosed monkey (Rhinopithecus roxellana) in Hubei Province,China

Using a case study of an isolated management unit of Sichuan snub‐nosed monkey (Rhinopithecus roxellana), we assess the extent that climate change will impact the species’ habitat distribution in the current period and projected into the 2050s. We identify refugia that could maintain the population under climate change and determine dispersal paths for movement of the population to future suitable habitats. Hubei Province, China. We identified climate refugia and potential movements by integrating bioclimatic models with circuit theory and least‐cost model for the current period (1960–1990) and the 2050s (2041–2060). We coupled a maximum entropy algorithm to predict suitable habitat for the current and projected future periods. Suitable habitat areas that were identified during both time periods and that also satisfied home range and dispersal distance conditions were delineated as refugia. We mapped potential movements measured as current flow and linked current and future habitats using least‐cost corridors. Our results indicate up to 1,119 km² of currently suitable habitat within the study range. Based on our projections, a habitat loss of 67.2% due to climate change may occur by the 2050s, resulting in a reduced suitable habitat area of 406 km² and very little new habitat. The refugia areas amounted to 286 km² and were located in Shennongjia National Park and Badong Natural Reserve. Several connecting corridors between the current and future habitats, which are important for potential movements, were identified. Our assessment of the species predicted a trajectory of habitat loss following anticipated future climate change. We believe conservation efforts should focus on refugia and corridors when planning for future species management. This study will assist conservationists in determining high‐priority regions for effective maintenance of the endangered population under climate change and will encourage increased habitat connectivity.     

Limited genetic diversity and high differentiation among the remnant adder (Vipera berus) populations in the Swiss and French Jura Mountains

Although the adder (Vipera berus) has a large distribution area, this species is particularly threatened in Western Europe due to high habitat fragmentation and human persecution. We developed 13 new microsatellite markers in order to evaluate population structure and genetic diversity in the Swiss and French Jura Mountains, where the species is limited to only a few scattered populations. We found that V. berus exhibits a considerable genetic differentiation among populations (global F_ST = 0.269), even if these are not geographically isolated. Moreover, the genetic diversity within populations in the Jura Mountains and in the less perturbed Swiss Alps is significantly lower than in other French populations, possibly due to post-glacial recolonisation processes. Finally, in order to minimize losses of genetic diversities within isolated populations, suggestions for the conservation of this species in fragmented habitats are proposed.     

Cold‐water coral habitats on seamounts: do they have a specialist fauna?

Aim The large biogenic structures formed by colonial cold‐water scleractinian corals provide valuable habitat for marine invertebrates on seamounts and the continental slope of all world oceans. These patchily distributed long‐lived structures are easily damaged by several human activities, particularly bottom trawling for fish, and are potentially vulnerable to ocean acidification caused by climate change. Consequently, an important conservation question is whether these structures support a specialized invertebrate fauna restricted to these habitats. Here we investigate the relationship between structures formed by the coral Solenosmilia variabilis and its associated ophiuroid (brittlestar) fauna, one of the dominant components of deep‐sea ecosystems. Location Seafloor habitat around Southern Australia, New Zealand, and the Macquarie Ridge from 35 to 53° S and 117° E–176° W, 500–1500 m depth. Methods Data were derived from samples collected by numerous scientific expeditions to the study region. Because these samples were collected using a variety of gear and effort, a two‐step approach was used. First, the largest consistently collected data set (73 ophiuroid species from 59 samples) was assembled for multivariate analysis. ANOSIM was used to test for differences in ophiuroid community composition between Solenosmilia and non‐Solenosmilia habitat on seamounts and the continental slope, and SIMPER was used to identify species that characterized Solenosmilia habitat. Second, these results were validated against all known data to ensure that these characteristic species had not been found in non‐Solenosmilia habitat elsewhere. Results The ophiuroid assemblages from Solenosmilia habitat were distinct from those found on other habitats on the continental slope and offshore seamounts across the study region. Although a suite of ophiuroid species characterized Solenosmilia habitat, most have also been collected from dead coral or other rubble, suggesting a physical rather than biological association between the coral matrix and its associated invertebrate fauna. Main conclusions Despite the lack of an exclusive ophiuroid–coral relationship, cold‐water scleractinian coral remains the principal habitat for a number of ophiuroid species across southern Australia and New Zealand. The slow growth rate of the coral and the low dispersal potential of some associated species suggest that recovery of damaged cold‐water coral assemblages will be a long‐term process.     

Influence of within‐patch habitat quality on high‐Andean Polylepis bird abundance

Habitat restoration strategies for fragmented high Andean forest landscapes must consider the influence of within‐patch habitat quality on bird abundance. I examined vegetation and bird abundance at three locations within a highly fragmented Polylepis forest landscape in the Cordillera Vilcanota, southern Peru. Across the landscape, there was significant variation in the vegetation structure of Polylepis forest patches of different size categories, especially in terms of tree girth, tree height, tree density, and canopy vegetation structure. Principal Component Analysis extracted five factors of habitat quality, which together accounted for 74.2% of the variability within 15 habitat variables. Polylepis bird species differed in their responses to habitat quality but, overall, variation in Polylepis bird abundance was not fully captured by the range of habitat quality variables. Tall, dense vegetation cover was clearly important for 11 conservation‐important species, a high density of large trees was important for 10 species and primary forest ground cover was important for eight species. Habitat quality exhibited no significant influence on the abundance of only one species –Asthenes urubambensis. The abundance of seven species was associated with lower elevation forest, but only one species was associated with higher elevation forest. Management of habitat quality in large and medium remnant forest patches throughout the Cordillera Vilcanota, particularly in the 3800–4200 m elevation range, will be a cornerstone in ensuring the persistence of the majority of conservation‐important bird species populations.     

Mapping potential habitats of threatened plant species in a moist tall grassland using hyperspectral imagery

We examined the capability of hyperspectral imagery to map habitat types of under-storey plants in a moist tall grassland dominated by Phragmites australis and Miscanthus sacchariflorus, using hyperspectral remotely-sensed shoot densities of the two grasses. Our procedure (1) grouped the species using multivariate analysis and discriminated habitat types (species groups) based on P. australis and M. sacchariflorus shoot densities, (2) used estimated shoot densities from hyperspectral data to draw a habitat type map, and (3) analyzed the association of threatened species with habitat types. Our identification of four habitat types, using cluster analysis of the vegetation survey coverage data, was based on P. australis and M. sacchariflorus shoot density ratios and had an overall accuracy of 77.1% (kappa coefficient = 0.71). Linear regression models based on hyperspectral imagery band data had good accuracy in estimating P. australis and M. sacchariflorus shoot densities (adjusted R ² = 0.686 and 0.708, respectively). These results enabled us to map under-storey plant habitat types to an approximate prediction accuracy of 0.537. Among the eight threatened species we examined, four exhibited a significantly biased distribution among habitat types, indicating species-specific habitat use. These results suggest that this procedure can provide useful information on the status of potential habitats of threatened species.     

Divergent habitat use of two urban lizard species

Faunal responses to anthropogenic habitat modification represent an important aspect of global change. In Puerto Rico, two species of arboreal lizard, Anolis cristatellus and A. stratulus, are commonly encountered in urban areas, yet seem to use the urban habitat in different ways. In this study, we quantified differences in habitat use between these two species in an urban setting. For each species, we measured habitat use and preference, and the niche space of each taxon, with respect to manmade features of the urban environment. To measure niche space of these species in an urban environment, we collected data from a total of six urban sites across four different municipalities on the island of Puerto Rico. We quantified relative abundance of both species, their habitat use, and the available habitat in the environment to measure both microhabitat preference in an urban setting, as well as niche partitioning between the two different lizards. Overall, we found that the two species utilize different portions of the urban habitat. Anolis stratulus tends to use more “natural” portions of the urban environment (i.e., trees and other cultivated vegetation), whereas A. cristatellus more frequently uses anthropogenic structures. We also found that aspects of habitat discrimination in urban areas mirror a pattern measured in prior studies for forested sites in which A. stratulus was found to perch higher than A. cristatellus and preferred lower temperatures and greater canopy cover. In our study, we found that the multivariate niche space occupied by A. stratulus did not differ from the available niche space in natural portions of the urban environment and in turn represented a subset of the niche space occupied by A. cristatellus. The unique niche space occupied by A. cristatellus corresponds to manmade aspects of the urban environment generally not utilized by A. stratulus. Our results demonstrate that some species are merely tolerant of urbanization while others utilize urban habitats in novel ways. This finding has implications for long‐term persistence in urban habitats and suggests that loss of natural habitat elements may lead to nonrandom species extirpations as urbanization intensifies.     

Global population structure and demographic history of the grey seal

Although the grey seal Halichoerus grypus is one of the most familiar and intensively studied of all pinniped species, its global population structure remains to be elucidated. Little is also known about how the species as a whole may have historically responded to climate‐driven changes in habitat availability and anthropogenic exploitation. We therefore analysed samples from over 1500 individuals collected from 22 colonies spanning the Western and Eastern Atlantic and the Baltic Sea regions, represented by 350 bp of the mitochondrial hypervariable region and up to nine microsatellites. Strong population structure was observed at both types of marker, and highly asymmetrical patterns of gene flow were also inferred, with the Orkney Islands being identified as a source of emigrants to other areas in the Eastern Atlantic. The Baltic and Eastern Atlantic regions were estimated to have diverged a little over 10 000 years ago, consistent with the last proposed isolation of the Baltic Sea. Approximate Bayesian computation also identified genetic signals consistent with postglacial population expansion across much of the species range, suggesting that grey seals are highly responsive to changes in habitat availability.     

Estimating the role of three mesopredatory fishes in coral reef food webs at Ningaloo Reef,Western Australia

Within the complex food webs that occur on coral reefs, mesopredatory fish consume small-bodied prey and transfer accumulated biomass to other trophic levels. We estimated biomass, growth and mortality rates of three common mesopredators from Ningaloo Reef in Western Australia to calculate their annual turnover rates and potential contribution to local trophic dynamics. Biomass estimates of the serranid Epinephelus rivulatus (4.46 ± 0.76 g m⁻²) were an order of magnitude greater than two smaller-bodied mesopredatory fishes, Pseudochromis fuscus (0.10 ± 0.03 g m⁻²) and Parapercis clathrata (0.23 ± 0.31 g m⁻²). Growth parameters generated from a von Bertalanffy growth function fitted to size-at-age data, however, indicated that mortality rates for the three mesopredators were similar and that 32–55 % of fish survived each year. Consequently, interspecific differences in annual turnover rates among E. rivulatus (1.9 g m⁻² yr⁻¹), Pa. clathrata (0.10 g m⁻² yr⁻¹) and Ps. fuscus (0.07 g m⁻² yr⁻¹) were an artefact of differences in local biomass estimates. The rapid turnover estimates for E. rivulatus suggest this species is an important conduit of energy within the isolated patch reef habitat where it is typically found, while Ps. fuscus and Pa. clathrata channel smaller amounts of energy from specific habitats in the Ningaloo lagoon. Apparent differences in habitat, diet and turnover rates of the three species examined provide an insight into the different roles these species play in coral reef food webs and suggest that life-history traits allow for variability in the local and spatial contribution of these species at Ningaloo Reef. Moreover, calculating turnover rates of a broader suite of fish species from a range of trophic groups will help better define the role of fishes in coral reef trophic dynamics.

     

Seasonal abundance and habitat use of bird species in and around Wondo Genet Forest,south‐central Ethiopia

The habitat use and seasonal migratory pattern of birds in Ethiopia is less explored as compared to diversity studies. To this end, this study aimed at investigating the patterns of distribution related to seasonality and the effect of habitat characteristics (elevation, slope, and average vegetation height) on habitat use of birds of Wondo Genet Forest Patch. A stratified random sampling design was used to assess the avian fauna across the four dominant habitat types found in the study area: natural forest, wooded grassland, grassland, and agroforestry land. A point transect count was employed to investigate avian species richness and abundance per habitat type per season. Ancillary data, such as elevation above sea level, latitude and longitude, average vegetation height, and percent slope inclination, were recorded with a GPS and clinometers per plot. A total of 33 migratory bird species were recorded from the area, of which 20 species were northern (Palearctic) migrants while 13 were inter‐African migrants. There was a significant difference in the mean abundance of migratory bird species between dry and wet seasons (t = 2.13, p = .038, df = 44). The variation in mean abundance per plot between the dry and wet seasons in the grassland habitat was significant (t = 2.35, p = .051, df = 7). In most habitat types during both dry and wet seasons, omnivore birds were the most abundant. While slope was a good predictor for bird species abundance in the dry season, altitude and average vegetation height accounted more in the wet season. The patch of forest and its surrounding is an important bird area for migratory, endemic, and global threatened species. Hence, it is conservation priority area, and the study suggests that conservation coupled with ecotourism development is needed for its sustainability.     

Life history influences how fire affects genetic diversity in two lizard species

‘Fire mosaics’ are often maintained in landscapes to promote successional diversity in vegetation with little understanding of how this will affect ecological processes in animal populations such as dispersal, social organization and re‐establishment. To investigate these processes, we conducted a replicated, spatiotemporal landscape genetics study of two Australian woodland lizard species [Amphibolurus norrisi (Agamidae) and Ctenotus atlas (Scincidae)]. Agamids have a more complex social and territory structure than skinks, so fire might have a greater impact on their population structure and thus genetic diversity. Genetic diversity increased with time since fire in C. atlas and decreased with time since fire in A. norrisi. For C. atlas, this might reflect its increasing population size after fire, but we could not detect increased gene flow that would reduce the loss of genetic diversity through genetic drift. Using landscape resistance analyses, we found no evidence that postfire habitat succession or topography affected gene flow in either species and we were unable to distinguish between survival and immigration as modes of postfire re‐establishment. In A. norrisi, we detected female‐biased dispersal, likely reflecting its territorial social structure and polygynous mating system. The increased genetic diversity in A. norrisi in recently burnt habitat might reflect a temporary disruption of its territoriality and increased male dispersal, a hypothesis that was supported with a simulation experiment. Our results suggest that the effects of disturbance on genetic diversity will be stronger for species with territorial social organization.