Amount Of Available Habitat Research Articles

Mesopredator predation risk limits northern bobwhite nesting habitat

AbstractPredators can significantly limit the amount of available habitat for vulnerable prey. Encouraging spatial segregation of predators and prey through habitat management prescriptions may be a useful tool to increase productivity and abundances of prey species of conservation concern. We estimated the total area of low‐risk nesting habitat by interacting predator habitat selection models with northern bobwhite (Colinus virginianus) nest‐site selection models. We used trail cameras, transect sampling, spotlighting transects, and incidental tracking to survey and map occurrences of mesopredators at a site in western Oklahoma, USA. We created broad‐scale resource selection function models for bobwhite nest‐site and mesopredator habitat selection using generalized linear models to create maps of occurrence probability in ArcGIS. Bobwhite nests were more likely to be depredated in areas of high selection by coyotes (Canis latrans) and striped skunks (Mephitis mephitis) compared to areas with low mesopredator selection. Approximately 392 ha of bobwhite nesting habitat (17%) had low probabilities of selection by both coyotes and striped skunks. Our results demonstrate the need for incorporating species' interactions into estimations of available habitat. Based on the total area of highly selected cover by northern bobwhite, approximately 29% of the study area would have been deemed suitable for nesting. However, only 5% of that area is predicted to have a low predation risk.

Conspecific density and habitat quality affect breeding habitat selection: Support for the social attraction hypothesis

AbstractBreeding habitat selection is a critical component of the annual cycle because of its effect on fitness. Multiple theories of habitat selection can be differentiated by their responses to the quantity of habitat, conspecific density, and habitat quality. Here, we use network analysis to understand the characteristics of fine‐scale breeding habitat selected by both immigrant and returning adult piping plovers (Charadrius melodus) to test five hypotheses of habitat selection. Between 2014 and 2019, we recorded 2034 uniquely marked adults breeding at 326 breeding locations with 1240 successive breeding events. Among adults, immigration events (i.e., individuals that moved to a new breeding location) were detected as often as fidelity to the same breeding location. We found support for the social attraction hypothesis for both immigrants and returners, indicating that adult plovers use social cues for settlement decisions. Adult plovers selected habitats with intermediate levels of conspecific density and high habitat quality, as assessed by con‐ and heterospecific nest survival, with no effect from the amount of available habitat. We also simulated the loss of breeding habitat and identified highly connected breeding locations, which occurred mostly on the riverine habitat type, which have important implications for habitat conservation for this listed species. Our results highlight the role of conspecifics at identifying high‐quality breeding habitat regardless of whether individuals return to the same breeding site or immigrate to new areas.

From island biogeography to landscape and metacommunity ecology: A macroecological perspective of bat communities

The equilibrium theory of island biogeography and its quantitative consideration of origination and extinction dynamics as they relate to island area and distance from source populations have evolved over time and enriched theory related to many disciplines in spatial ecology. Indeed, the island focus was catalytic to the emergence of landscape ecology and macroecology in the late 20th century. We integrate concepts and perspectives of island biogeography, landscape ecology, macroecology, and metacommunity ecology, and show how these disciplines have advanced the understanding of variation in abundance, biodiversity, and composition of bat communities. We leverage the well-studied bat fauna of the islands in the Caribbean to illustrate the complex interplay of ecological, biogeographical, and evolutionary processes in molding local biodiversity and system-wide structure. Thereafter, we highlight the role of habitat loss and fragmentation, which is increasing at an accelerating rate during the Anthropocene, on the structure of local bat communities and regional metacommunities across landscapes. Bat species richness increases with the amount of available habitat, often forming nested subsets along gradients of patch or island area. Similarly, the distance to and identity of sources of colonization influence the richness, composition, and metacommunity structure of islands and landscape networks.

Patterns and Drivers of Rodent Abundance across a South African Multi-Use Landscape.

Simple SummaryWildlife ecological patterns are driven not only by environmental and biological contexts, but also by landscape-management schemes that shape those contexts. The present study aims to determine the effect of different environmental factors (including management schemes) on the occurrence patterns of a southern African small mammal community. Based on a landscape where three land-use contexts that differ in their levels of human presence and/or where activities coexist (private ecotourism reserve, mixed farms and traditional communal areas), and by using a body-size-based approach (i.e., using two size-based rodent groups—medium and small—as models), we found that the mean relative abundance of medium-sized species did not differ across the management contexts, but small species’ mean relative abundance was higher in the game reserve. The overall variation in rodent abundance was negatively affected by ungulate presence (possibly linked to a decrease in food availability) and by human presence (increased disturbance). Rodent abundance seems to be influenced by environmental gradients that are directly linked to varying management priorities across land uses, meaning that these communities might not benefit uniformly by the increased amount of habitat promoted by the commercial wildlife industry.South Africa’s decentralized approach to conservation entails that wildlife outside formally protected areas inhabit complex multi-use landscapes, where private wildlife business (ecotourism and/or hunting) co-exist in a human-dominated landscape matrix. Under decentralized conservation, wildlife is perceived to benefit from increased amount of available habitat, however it is crucial to understand how distinct management priorities and associated landscape modifications impact noncharismatic taxa, such as small mammals. We conducted extensive ink-tracking-tunnel surveys to estimate heterogeneity in rodent distribution and investigate the effect of different environmental factors on abundance patterns of two size-based rodent groups (small- and medium-sized species), across three adjacent management contexts in NE KwaZulu-Natal, South Africa: a private ecotourism game reserve, mixed farms and traditional communal areas (consisting of small clusters of houses interspersed with grazing areas and seminatural vegetation). Our hypotheses were formulated regarding the (1) area typology, (2) vegetation structure, (3) ungulate pressure and (4) human disturbance. Using a boosted-regression-tree approach, we found considerable differences between rodent groups’ abundance and distribution, and the underlying environmental factors. The mean relative abundance of medium-sized species did not differ across the three management contexts, but small species mean relative abundance was higher in the game reserves, confirming an influence of the area typology on their abundance. Variation in rodent relative abundance was negatively correlated with human disturbance and ungulate presence. Rodent abundance seems to be influenced by environmental gradients that are directly linked to varying management priorities across land uses, meaning that these communities might not benefit uniformly by the increased amount of habitat promoted by the commercial wildlife industry.

Larval development and survival of pond-breeding anurans in an agricultural landscape impacted more by phytoplankton than surrounding habitat.

The destruction of freshwater habitat is a major contributor to biodiversity loss in aquatic ecosystems. However, created or restored wetlands could partially mitigate aquatic biodiversity loss by increasing the amount of available habitat across a landscape. We investigated the impact of surrounding terrestrial habitat and water quality variables on suitability for two species of pond-breeding amphibians (bullfrogs [Lithobates catesbeianus] and Blanchard's cricket frogs [Acris blanchardi]) in created permanent wetlands located on an agricultural landscape. We examined tadpole growth and survival in field enclosures placed in ponds surrounded by agricultural, forested, or grassland habitats. We also evaluated the potential for carryover effects of the aquatic environment on terrestrial growth and overwinter survival of cricket frog metamorphs. We found that habitat adjacent to ponds did not predict tadpole growth or survival. Rather, phytoplankton abundance, which showed high variability among ponds within habitat type, was the only predictor of tadpole growth. Cricket frogs emerged larger and earlier from ponds with higher phytoplankton abundance; bullfrogs were also larger and at a more advanced developmental stage in ponds with higher levels of phytoplankton. Overwinter survival of cricket frogs was explained by size at metamorphosis and there were no apparent carryover effects of land use or pond-of-origin on overwinter growth and survival. Our results demonstrate that created ponds in human-dominated landscapes can provide suitable habitat for some anurans, independent of the adjacent terrestrial habitat.

Landscape attributes explain salmonid ecological neighbourhoods across a complex river network

Abstract Defining population neighbourhood boundaries provides a critical spatial framework for understanding ecological processes and informing species‐specific conservation and restoration planning. The population neighbourhood boundary demarcates the total quantity of available habitat across life stages where specific ecological processes (e.g., breeding, foraging, migration) occur for all individuals within a population. For mobile species within dendritic freshwater networks, the population neighbourhood boundary can be defined by the upper limit of occurrence (ULO) of an individual within a population. We sought to define contemporary neighbourhood boundaries across a complex river network in southwestern Washington State, U.S.A. by: (1) identifying ULOs for three anadromous fish (Oncorhynchus spp.); and (2) quantifying the relationship of the ULO with landscape attributes and local features for these species of profound social and ecological importance. Extensive field surveys covering 669 river km across 2 years documented the ULOs for coho salmon (Oncorhynchus kisutch), steelhead trout (Oncorhynchus mykiss), and chum salmon (Oncorhynchus keta) as well as any local features, such as natural barriers, that influenced the ULOs. Generalised linear mixed models quantified the relationships between the ULOs and landscape attributes derived from remote sensing data. We identified the ULO for 115 coho salmon terminal streams, 97 steelhead streams, and 57 chum salmon streams. Natural barriers determined the ULO in just 5%–16% of the terminal streams, depending on species. Landscape attributes associated with the ULOs varied among species; however, drainage area, elevation, and geology were important landscape predictors for all species. Models for each species had good to excellent predictive performance (percent correct classification: 78%–89%; AUC: 0.87–0.96). We demonstrated that large‐scale landscape attributes can accurately and consistently detect species‐specific differences in population neighbourhoods across broad and diverse habitats. In comparison, local scale features (e.g., natural barriers) played a minor role in determining the neighbourhood boundaries in our study catchment. The modelled relationships between landscape attributes and the population neighbourhood provide a framework to guide conservation planning and predict benefits of habitat reconnections.

On the tiger trails: Leopard occupancy decline and leopard interaction with tigers in the forested habitat across the Terai Arc Landscape of Nepal

Better conservation planning requires updated information about leopard distribution to prioritize and allocate limited resources available. The long-term persistence of leopards and sympatric tigers can be compromised by linear infrastructure development such as roads that fragment habitat. We used detection and non-detection data collected along walking search paths (~4140 km) in 96 grid cells (each cell 15 km by 15 km) spread across potential habitat (~13,845 km2) in the Terai Arc Landscape, Nepal. Multi-season occupancy models allowed us to make both spatial and temporal inferences between two surveys in 2009 and 2013, based on ecologically relevant covariates recorded in the field or remotely sensed. Additionally, we used 2013 data to make inferences on co-occurrence between tigers and leopards at the landscape level. We found the additive model containing deforestation and district roads negatively influenced leopard detection across the landscape. Although weak, we found anthropogenic factors such as extent of deforestation (decrease in forest cover) negatively affected leopard occupancy. Road abundance, especially for the east-west highway and district roads, also negatively (but weakly) influenced leopard occupancy. We found substantially lower occupancy in the year 2013 (0.59 (SE 0.06)) than in 2009 (0.86 (SE 0.04)). Tigers and leopards co-occurred across the landscape based on the species interaction factor (SIF) estimated at 1.47 (0.13) but the amount of available habitat and the prey index mediated co-occurrence. The SIF decreased as habitat availability increased, reaching independence at large habitat patches, but leopard occupancy declined in sites with tigers, primarily in large patches. The prey index was substantially lower outside of protected areas and leopards and tigers co-occurred more strongly in small patches and at low prey indices, indicating potential attraction to the same areas when prey is scarce. Mitigation measures should focus on preventing loss of critical leopard, tiger, and prey habitat through appropriate wildlife-friendly underpasses and avoiding such habitat when building infrastructure. Leopard conservation has received lower priority than tigers, but our metrics show a large decline in leopard occupancy, thus conservation planning to reverse this decline should focus on measures to facilitate human-leopard coexistence to ensure leopard persistence across the landscape.

Wild bee distribution near forested landscapes is dependent on successional state

BackgroundForested landscapes are valuable sources of ecosystem services especially in areas dedicated to intense agricultural activities. Distance from forest margin is known to influence the wild bee community in the landscape surrounding forested patches. Yet little is known regarding how bee communities distribute themselves in landscapes that exhibit different forest successional states.MethodsWe examined how land use type and distance from the forest edge affect the abundance and richness of the wild bee community across four forest successional states. Bees were collected in sites representing four stages of forest succession and analyzed using generalized linear mixed models with negative binomial distributions.ResultsWild bee diversity is reduced in forested environments that maintain dense stands of trees and high canopy cover. Additionally, distance from the forest edge was an important factor determining wild bee distribution in successional stages adjacent to forest edges. Furthermore, we found that bees maintain high specificity for distinct successional states and distances.ConclusionsOur results demonstrate how different successional stages can harbor different bee species and highlight the ability of microhabitats to act as reservoirs of bee diversity in and around forest margins. Furthermore, we found that maximizing successional patchiness across forested landscapes increases the amount of available habitat that can support a diverse suite of bees with different nesting biologies and behaviors.

Habitat variability in an underwater forest: Using a trait‐based approach to predict associated communities

Abstract By providing food, living space and reducing biotic and abiotic stress, habitat‐formers support diverse communities. The characteristics that mediate their value to associated organisms, however, are not always clear. Traditional assessments of habitat‐former and associated community relationships use broad‐scale classifications to group habitat‐formers according to identity or gross morphology. Trait‐based approaches instead measure traits at the level of the individual and in doing so allow for predictions that are not constrained to taxonomic groups. By measuring at the level of the individual, trait‐based approaches have the potential to capture not only interspecific variability, but also the intraspecific variation that is often ignored by traditional approaches. Trait‐based approaches may therefore provide a novel way to link the characteristics of habitat‐formers to ecosystem functioning. Here we quantified inter‐ and intraspecific variation in six macroalgal species and tested the relative importance of morphological traits and species identity in predicting the abundance of associated fauna. All species of macroalgae displayed substantial intraspecific morphological variation. Morphological traits were more important than species identity in predicting epifaunal abundances. Total surface area was the most important trait when predicting total abundance per thallus, whilst mean frond length was the most important predictor for abundance per gram algal biomass. This suggests that traits that describe the quantity of available habitat were the most important predictors of community abundance, but the shape or architecture of the habitat also contributes to structuring these communities. Our results indicate that trait‐based approaches may be more useful than traditional species‐based approaches when predicting the abundances of fauna associated with habitat‐forming species. A free Plain Language Summary can be found within the Supporting Information of this article.

Notes on the cultural value, biology and conservation status of the Data Deficient Tagula butcherbird (Cracticus louisiadensis Tristram, 1889)

The Tagula butcherbird (Cracticus louisiadensis) is an endemic island species of butcherbird that has remained virtually unknown for over 130 years. The lack of information on the species has resulted in it being assigned to the Data Deficient category by BirdLife International and the IUCN, leaving its conservation status open to continuing speculation. This is an ongoing concern given the rapid environmental changes occurring in the region. Here, we describe the first observations of the habitat use, life history and ecology of the species. We also present information collected across the island distribution of the species, including density and population estimates. We found the Tagula butcherbird to be culturally important and relatively common in suitable habitats across four islands of the Louisiade Archipelago (Papua New Guinea). However, the species was absent from highly disturbed areas. We estimated this species’ extent of occurrence to be ~1200km2 and area of occupancy to be less than 800km2. Population densities were estimated via pre-dawn assessments of singing birds and line transects. Density estimates were found to be between 0.14 and 0.53 individuals per hectare, with the highest density observed on Sabara Island. These densities were combined with remote sensing data to estimate the amount of available habitat and the species’ population size, which was estimated to be between ~11500 and 23000 individuals. The species’ dependence on forest habitat with a relatively intact canopy, combined with the likely continuing destruction of habitat on Junet and Panawina Islands, remains a conservation concern.

At the landscape level, birds respond strongly to habitat amount but weakly to fragmentation

AbstractAimIt is usually thought that habitat fragmentation acts negatively on species survival, and consequently, on biodiversity. Recent literature challenges whether habitat fragmentation per se affects species richness, beyond the effect of habitat area. Theoretical studies have suggested that fragmentation may matter most when the amount of available habitat is small or at intermediate levels. However, a recent review suggests that the effect of fragmentation on species richness is usually positive. Here, we dissect the richness–fragmentation relationship. What is the effect size? Does it depend upon the amount of habitat cover? How do individual species respond to fragmentation?MethodsApplying a macroecological approach, we empirically related avian richness and the probability of occurrence (pocc) of individual species to fragmentation (number of patches), after controlling for habitat amount in 991 landscapes, each 100‐km2, in southern Ontario, Canada.ResultsSpecies richness was strongly related to total habitat amount, but habitat fragmentation had no detectable additional effect. Individual species’ pocc related strongly to habitat amount. For some species, pocc also related secondarily to habitat fragmentation within landscapes. Logistic models revealed that pocc related significantly negatively to fragmentation after controlling for habitat amount for only ~13% of forest‐ and 18% of open‐habitat species bird species. However, pocc related significantly positively to fragmentation for even greater proportions of species, including some red‐listed species. Fragmentation effects were not stronger at low or intermediate levels of habitat amount within landscapes.ConclusionIn earlier studies, negative effects of isolation were observed at the patch level in experimental manipulations. However, at the landscape level, avian species richness in southern Ontario apparently responds primarily to habitat amount and negligibly to fragmentation. We argue that the evidence is inconsistent with the hypothesis that reducing habitat fragmentation per se would be an effective conservation strategy for birds at the landscape level.

Physical Habitat Assessment of the Ganjal and Morand River Using GIS Techniques

Physical habitat is the living space of in-stream biota which is an important factor that can affect both the quality and quantity of available habitat and the structure and composition of resident biological communities. It is a spatially and temporally dynamic entity determined by the interaction of the structural features of the channel and hydrological regime. Ganjal River is a left bank tributary of River Narmada and Morand river is the major tributary of it. At these rivers Physical Habitat Assessment was carried out using USEPA Rapid Bioassessment Protocols to know habitat suitability conditions in rivers for aquatic life thrive in. In the study habitat assessment parameters were scored according to the existing conditions for each section of the rivers and were categorised under four conditions i.e. optimal, suboptimal, marginal and poor. On the basis of result obtained from the study Habitat Suitability Map (HSM) was generated using GIS as an interface and it suggests that the habitat quality of both rivers is suitable for aquatic life.

Mule deer and energy development-Long-term trends of habituation and abundance.

As the extent and intensity of energy development in North America increases, so do disturbances to wildlife and the habitats they rely upon. Impacts to mule deer are of particular concern because some of the largest gas fields in the USA overlap critical winter ranges. Short-term studies of 2-3years have shown that mule deer and other ungulates avoid energy infrastructure; however, there remains a common perception that ungulates habituate to energy development, and thus, the potential for a demographic effect is low. We used telemetry data from 187 individual deer across a 17-year period, including 2years predevelopment and 15years during development, to determine whether mule deer habituated to natural gas development and if their response to disturbance varied with winter severity. Concurrently, we measured abundance of mule deer to indirectly link behavior with demography. Mule deer consistently avoided energy infrastructure through the 15-year period of development and used habitats that were an average of 913m further from well pads compared with predevelopment patterns of habitat use. Even during the last 3years of study, when most wells were in production and reclamation efforts underway, mule deer remained >1km away from well pads. The magnitude of avoidance behavior, however, was mediated by winter severity, where aversion to well pads decreased as winter severity increased. Mule deer abundance declined by 36% during the development period, despite aggressive onsite mitigation efforts (e.g. directional drilling and liquid gathering systems) and a 45% reduction in deer harvest. Our results indicate behavioral effects of energy development on mule deer are long term and may affect population abundance by displacing animals and thereby functionally reducing the amount of available habitat.

Functional implications of changes in seagrass species composition in two shallow coastal lagoons

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 557:111-121 (2016) - DOI: https://doi.org/10.3354/meps11847 Functional implications of changes in seagrass species composition in two shallow coastal lagoons Bart Christiaen1,*, John C. Lehrter2, Joshua Goff 3, Just Cebrian3,4 1Washington Department of Natural Resources, Olympia, WA 98504, USA 2US EPA, Gulf Ecology Division, Gulf Breeze, FL 32561, USA 3Dauphin Island Sea Lab, Dauphin Island, AL 36528, USA 4University of South Alabama, Mobile, AL 36608, USA *Corresponding author: bart.christiaen@dnr.wa.gov ABSTRACT: While the consequences of losing seagrass meadows are well known, there is less information on the functional implications of changes in seagrass species composition. In this study, we use data from a long-term monitoring project in shallow lagoons on the Florida Gulf Coast to assess changes in the functional attributes of seagrass beds during a shift in seagrass species composition. We compare seagrass beds in 2 neighboring lagoons with different trends: one where the composition changed from 100% Halodule wrightii to a mixed bed with up to 60% Ruppia maritima, and one where the species composition remained unchanged. Our results indicate that the partial replacement of H. wrightii by R. maritima did not alter seagrass biomass m-2, detrital biomass m-2, benthic gross primary production, or benthic respiration. However, there was a small positive effect on benthic net primary production. While seagrass biomass m-2 declined at both sites, the emergence of R. maritima increased the amount of available habitat through rapid expansion. Overall, our data suggest that shifts between 2 seagrass species with similar morphology, but different ecological strategies, may have little impact on the ecosystem services of seagrass beds in shallow coastal lagoons. KEY WORDS: Ruppia maritima · Halodule wrightii · Seagrass · Species shift · Ecosystem metabolism Full text in pdf format PreviousNextCite this article as: Christiaen B, Lehrter JC, Goff J, Cebrian J (2016) Functional implications of changes in seagrass species composition in two shallow coastal lagoons. Mar Ecol Prog Ser 557:111-121. https://doi.org/10.3354/meps11847 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 557. Online publication date: September 28, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Buffer zone use by mammals in a Cerrado protected area

Habitat loss and degradation is threatening mammals worldwide. Therefore, Protected Areas (PA) are of utmost importance to preserve biodiversity. Their effectiveness, however, depends on some management strategies such as buffer zones, which prevent/mitigate the impact of external threats and might increase the amount of available habitat for wildlife existing within reserves. Nevertheless, how intensively terrestrial mammals use buffer zones remains little studied, particularly in the Neotropical region. Aiming to analyse the use of a buffer zone (5 km wide) by medium and large-sized mammals, we modelled the occupancy probabilities of five species of conservation concern including local (interior and buffer zone) as a site covariate, simultaneously controlling for imperfect detection. Data collection was made with camera traps from April to September 2013 in a 9000 ha Cerrado PA (“interior”) and in its surrounding area (39721.41 ha; “buffer zone”). This PA (Jataí Ecological Station) is immersed in a landscape where sugarcane plantations predominate in the northeastern of the state of São Paulo. We also conducted an inventory to compare the number and composition of species between interior and buffer zone. A total of 31 mammal species (26 natives) was recorded via camera traps and active search for sightings, vocalizations, tracks and signs. Occupancy estimates for Myrmecophaga tridactyla, Leopardus pardalis and Pecari tajacu were numerically higher in interior. On the other hand, Chrysocyon brachyurus had the highest occupancy in buffer zone, while the largest predator, Puma concolor, used both areas similarly. However, as the confidence intervals (95%) overlapped, the differences in occupancy probabilities between interior and buffer were weak for all these species. Additionally, regarding only the species recorded by cameras, the observed and estimated richness were similar between interior and buffer zone of the PA. Our data demonstrated that the buffer zone is indeed used by medium and large-sized mammals, including conservation-dependent ones. The lack of enforcement of current legislation regarding buffer zones is therefore a real threat for mammals, even when protection is guaranteed in the interior of protected areas.

Population trends of colonial waterbirds nesting in Hamilton Harbour in relation to changes in habitat and management

Since 1975, the diversity and abundance of colonial waterbirds breeding in Hamilton Harbour have increased, making it an important nesting site on the Great Lakes. An adaptive management approach has been employed to control hyper-abundant species and guide conservation efforts for vulnerable species, with the goal of maintaining a diverse waterbird community. Four species exhibited increasing or stable population trends (1975–2013): Double-crested Cormorants (Phalacrocorax auritus; from 0 to 4747 nests); Black-crowned Night-Herons (Nycticorax nycticorax; ranged from 6 to 259 nests); Herring Gulls (Larus argentatus; from 0 to 244 nests); and Caspian Terns (Hydroprogne caspia; from 0 to 496 nests). Cormorants are currently above (2,500 nests), while Caspian Terns (400–600 nests), Night-Herons (100–200 nests) and Herring Gulls (200–300 nests) are within population targets set out in the Hamilton Harbour Remedial Action Plan. Despite conservation efforts, Common Terns (Sterna hirundo) declined from a peak of 1,028 nests (1990) to 333 nests (2013), although currently within the population target (300–600 nests). Ring-billed Gulls (L. delawarensis), through long-term management and habitat restrictions, were reduced from a peak of 39,621 nests (1990) to 11,133 nests (2013), but still exceed the target (<10,000 nests). Changes in the amount of available habitat have affected waterbird distributions: the loss of 42 ha (peak in 1999) of former nesting areas to development has been partially offset by the creation or securement of 1.9 ha of dedicated breeding habitat. Continued management, assessed and refined annually, is required to maintain species diversity in the area. Current management techniques focus on preventing Ring-billed Gulls from nesting on private lands and dedicated Tern nesting habitat, excluding Cormorants from nesting at specific sites, and reducing inter-specific competition with Night-Herons and Herring Gulls. Recommendations and considerations regarding future management and conservation efforts to reach Remedial Action Plan targets in the harbor are outlined.

전주천 상류부의 서식처 적합도 지수 및 생태유량 산정

In this study, WUA (Weighted Usable Area) based on the Instream Flow Incremental Methodology (IFIM) was calculated to determine ecological flow at JeonJu-Cheon by using River2D model. To calibrate River2D, simulation results for low flow conditions of River2D were compared with calibrated HEC-RAS simulation results and the optimum parameters were determined. The results were RMSE (0.18), NSE (0.71) and coefficient of determination (0.78) for velocity and RMSE (0.02), NSE (0.71), coefficient of determination (0.73) for water depth. The result shows that the model successfully simulates the water flows. A selected target fish species to build the habitat suitability index were composed of Zaccoplatypus and Coreoleuciscus splendidus. These species showed the highest occurrences over the past decade in f ish monitoring. Also, The WUA-Discharge curve was calculated with the suitability index in a medium flow conditions. From the result, WUA is changed according to flowrate. In the flowrate-WUA/A graph, ecological flow can be determined at 1.8~2.0 m/s for Zaccoplatypus 2.0 m/s and Coreoleuciscus splendidus 1.8 m/s at JeonJu-Cheon upstream. When compared with flow-duration analysis, it is demonstrative that simulation results fitted ecological flow considering quantity of available habitat for each fish species.

Evolution at a different pace: distinctive phylogenetic patterns of cone snails from two ancient oceanic archipelagos.

Ancient oceanic archipelagos of similar geological age are expected to accrue comparable numbers of endemic lineages with identical life history strategies, especially if the islands exhibit analogous habitats. We tested this hypothesis using marine snails of the genus Conus from the Atlantic archipelagos of Cape Verde and Canary Islands. Together with Azores and Madeira, these archipelagos comprise the Macaronesia biogeographic region and differ remarkably in the diversity of this group. More than 50 endemic Conus species have been described from Cape Verde, whereas prior to this study, only two nonendemic species, including a putative species complex, were thought to occur in the Canary Islands. We combined molecular phylogenetic data and geometric morphometrics with bathymetric and paleoclimatic reconstructions to understand the contrasting diversification patterns found in these regions. Our results suggest that species diversity is even lower than previously thought in the Canary Islands, with the putative species complex corresponding to a single species, Conus guanche. One explanation for the enormous disparity in Conus diversity is that the amount of available habitat may differ, or may have differed in the past due to eustatic (global) sea level changes. Historical bathymetric data, however, indicated that sea level fluctuations since the Miocene have had a similar impact on the available habitat area in both Cape Verde and Canary archipelagos and therefore do not explain this disparity. We suggest that recurrent gene flow between the Canary Islands and West Africa, habitat losses due to intense volcanic activity in combination with unsuccessful colonization of new Conus species from more diverse regions, were all determinant in shaping diversity patterns within the Canarian archipelago. Worldwide Conus species diversity follows the well-established pattern of latitudinal increase of species richness from the poles towards the tropics. However, the eastern Atlantic revealed a striking pattern with two main peaks of Conus species richness in the subtropical area and decreasing diversities toward the tropical western African coast. A Random Forests model using 12 oceanographic variables suggested that sea surface temperature is the main determinant of Conus diversity either at continental scales (eastern Atlantic coast) or in a broader context (worldwide). Other factors such as availability of suitable habitat and reduced salinity due to the influx of large rivers in the tropical area also play an important role in shaping Conus diversity patterns in the western coast of Africa.

Does urbanization have the potential to create an ecological trap for powerful owls (Ninox strenua)?

Landscape transformation associated with urbanization is one of the most damaging and pervasive impacts humans have on natural ecosystems. The response of species to increasing urbanization has become a major focus of research globally. Powerful owls (Ninox strenua) are a top-order predator the have been shown to reside in urban environments, but increasing urbanization has also been demonstrated to significantly reduce available habitat. In this paper we use species distribution models established for key food and nesting resources of powerful owls across an urban-forest gradient to constrain habitat predictions from a previously developed powerful owl species distribution model. This multi-criteria decision analysis (MCDA) approach allowed us to investigate the impacts of urbanization on potential powerful owl habitat when challenged with food and nesting requirements. As powerful owls only use tree cavities for nesting we propose that the cue for settlement in an area is associated with the presence of habitat and food and as such breeding requirements may be disconnected from settlement requirements.Our results demonstrate that incorporation of a general prey resource (at least one group of arboreal marsupials) as a cue for settlement does not reduce the amount of available habitat for powerful owls substantially. Further constraining the model with a tree cavity resource, however, leads to a substantial reduction in powerful owl habitat in the urban and urban fringe environments. If a diverse prey resource (two or more groups of arboreal marsupials) is used as the cue for settlement, this sees a substantial reduction in available habitat in urban environments. Incorporation of tree cavities into this model does not reduce the available habitat for powerful owls substantially.We propose that powerful owls do not need a diverse prey base for survival, and that breeding resources are unlikely to be a cue for settlement. As such, we argue in this paper that increasing urbanization has the potential to create an ecological trap for powerful owls as there is a significant difference between habitat capable of supporting powerful owls, and habitat in which owls can breed.Management of powerful owls in urban environments will be difficult, but this research highlights the potential for the use of nest boxes to enhance the breeding activities in increasingly urbanized environments. Replacement of this critical resource may be able to reverse any potential ecological trap that is occurring.

Diversidad de aves en el Centro Agropecuario Cotové, Santa Fe de Antioquia, Colombia

Fragmentation of natural habitats is a central concern of biodiversity conservation and is considered a significant factor contributing to species loss and populations decline. We studied this in Cotové Agricultural Center in the municipality of Santa Fe de Antioquia (Colombia),where the conversion of natural forests to different land use systems, has limited the amount of available habitat. With the aim to describe the effect of habitat loss on bird presence in five land uses (fruiting trees, silvopastoral systems, secondary forest, pasture low density of trees and grass cutting) in this area, we studied bird diversity using two methods: fixed point counts and mist nets to analyze the influence of land use in the composition, richness and abundance of birds present were studied. A total of 6633 individuals of 101 species were observed of which 11 species were migratory. The insectivorous and frugivorous foraging guilds were better represented. The Shannon index indicated the highest values of alpha diversity for the silvopastoral system, and the fruit with the lowest. The grazing and silvopastoral land systems shared more species with low tree density. The importance of the environmental heterogeneity found is highlighted as a positive factor for bird species richness, mostly of low and middle habitat specificity, and preferably from edge habitats and open areas. In order to preserve natural regeneration and connectivity between different land use types, and to promote stability of bird species populations, some management actions should be implemented in the area.