Habitat associations of wild goat in central Iran: implications for conservation

Wild goat (Capra aegagrus) is one of the highly valued but threatened ungulates of Iran. Seasonal habitat use of wild goat was studied from October 2006 to September 2008 in Haftad Gholleh Protected Area, central Iran. We developed averaged logistic regression models based on Akaike Information Criterion weights for each season. The obtained habitat suitability models showed high sensitivity (greater than 88%) for all evaluation datasets. Wild goat habitat use was positively related with steep slopes, areas near rocky substrates and water sources, west-facing slopes and areas far from roads in all seasons. Core zones of protected area covered nearly 70% of suitable habitats for wild goats, predicted by logistic regression models. Northern core zone covered more than 61% of predicted suitable habitats, which should receive more attention in management actions. The southern core zone boundaries should be considered to increase the encompassed suitable habitats. There was a substantial overlap between seasonal suitable habitats with the highest overlap observed between spring and summer and summer and fall.     

Mycorrhizal infection indicates the suitability of different management treatments for nature conservation in calcareous grassland

The vegetation composition of calcareous grasslands in Central Europe is mainly determined by the applied management treatments and the nutrient status of the ecosystems, but these factors cannot clearly be separated. Recently several authors reported a shift in growth-limiting plant nutrients from nitrogen to phosphate. Therefore, we tested the interaction between management and plant available phosphate in a long-term experiment in Southern Germany with different management treatments applied to calcareous grassland. We measured mycorrhization rates, which are assumed to be high at low phosphate availability, to explore the interaction between management, phosphate availability and vegetation composition. By correlating mycorrhization rates to vegetation and soil data we found that treatments involving nutrient removal show a greater degree of mycorrhization than treatments leading to nutrient enrichment. According to decreasing suitability for grassland conservation, the six different management treatments could be ranked as mowing, followed by mulching (twice a year, once a year and every second year), burning and undisturbed succession. It was shown, that mycorrhizal infection rates (1) can be used to evaluate different management treatments for their suitability to conserve the initial vegetation composition, and (2) may provide information about the processes of adaptation to the current management, namely to differences in plant available phosphate. However, as discussed for the undisturbed succession treatment, it might not be sufficient to look at the degree of mycorrhization only. These are related to phosphate availability, but to detect adaptation processes to management, the degree of mycorrhization should be analysed together with plant’s internal nutrient relocation patterns.     

Habitat selection by grassland snakes at northern range limits: Implications for conservation

Animal populations at northern range limits may use habitat differently from those at range cores, requiring distinct conservation plans. Snakes are ectotherms that often have very specific requirements, but few studies have focused on the effect of northern latitudes on habitat selection by grassland snakes. We studied movement and habitat selection of 2 sympatric snake species at their northern range limits on the North American Great Plains: the eastern yellow-bellied racer (Coluber constrictor flaviventris, hereafter racer), a Threatened species in Canada, and the bullsnake (Pituophis catenifer sayi), which is listed as Data Deficient. Both of these species are potentially vulnerable to extinction in Canada because of habitat loss. Snakes from our study populations traveled up to 10-times farther from winter dens and occupied home ranges 3–104 times larger than populations further south. Both snake species moved from winter dens in the slopes of a major river valley to habitat in adjacent lowlands, including riparian zones (racers) and hilly areas with native grass species (bullsnakes). Multivariate modeling revealed that proximity to retreat sites was a significant predictor of snake site use for both species. Considering the need for winter dens and summering areas, our data suggest that snakes in northern latitudes should ideally have much larger protected areas compared to snakes near the core of their range. An alternative strategy is to conserve corridors linking wintering dens and summer habitats. Retreat sites such as burrows and shrubs are critical components of local habitat and should be included in conservation plans. © 2011 The Wildlife Society.     

Effects of grassland intensification on Whinchats Saxicola rubetra and implications for conservation in upland habitats

Modern, intensive grassland management has led to strong declines in ground‐nesting grassland birds, and is now increasingly threatening the last remaining strongholds of the Whinchat Saxicola rubetra in the Central European uplands. In this study, we assess key threats to Whinchat populations in these uplands in order to suggest appropriate conservation measures. We compared the direct threat of early mowing as well as the indirect threat resulting from a deteriorating arthropod food source in an inner‐alpine valley. Five of our seven study sites were mown too early with respect to the chicks' fledging date. Such early mowing was particularly evident on the more intensively farmed, earlier mown valley bottoms than on the valley slopes. Arthropod abundance and biomass did not differ between valley bottoms and slopes. However, valley bottoms had a greater amount of unprofitable prey items such as flies. Breeding bird density was mainly determined by the degree of overlap between the mowing schedule and breeding phenology. These findings suggest that in upland grasslands at an early stage of intensification, early mowing is of greater importance for populations than possible negative effects of a reduced food source. We suggest that mowing is delayed until a sufficient proportion of nestlings are safely fledged.     

Habitat associations of Yellow Wagtails Motacilla flava flavissima on lowland wet grassland

In common with many other previously widespread British birds, Yellow Wagtail Motacilla flava flavissima populations have declined substantially in the UK in recent decades. Recent national data suggest particular problems in grassland. We investigated how habitat management in a grassland area of East Anglia, England, influenced the habitat selection of this species. Breeding territories were associated with fields previously subject to prolonged winter floods and which contained shallow-edged ponds or wet ditches during summer. Territories were also associated with fields with short, sparse swards and high proportions of bare earth within the sward, and these features were themselves associated with previous winter flooding. However, nests were associated with taller swards than were random points within the same field, suggesting that Yellow Wagtails would benefit from within-field heterogeneity of sward height to provide both nesting and foraging habitat. We discuss how grazing, cutting and water-level management regimes could be used to promote optimal sward structure for Yellow Wagtails.     

Habitat selection by threatened burrowing spiders (Araneae: Atypidae,Eresidae) of central Europe: evidence base for conservation management

Habitat selection in sedentary, long-lived burrowing spiders is a key life-history event that directly affects their reproductive success. In this study, we analyzed the role of the chemical and physical properties of soil in habitat selection by threatened temperate burrowing spiders. We examined 296 burrows of three Atypus spp. and three Eresus spp. at 68 sites in Czechia. We found that the study species were associated with soils that have high or very high cation exchange capacity, which allows the presence of a stable and humid microclimate in their burrows. We found that specific bedrock types can be used as predictors of the presence of particular study species. All Eresus spp. avoided compacted soils. However, when present in soils with very low penetration resistance, they were limited to sites with high soil cohesion. The burrows of all study species were located at well-drained sites. The study species seemed to be selective for a steppe-like character of their microhabitat but not necessarily for its southward orientation. We found the study species even at sites where steppes were present in the early 1950s and that underwent later afforestation but not extensive landscaping or plowing. What types of disturbances can be sustained by the study species and how long it takes the decreased populations to recover after, e.g., trampling associated with grazing, remain to be investigated.     

Habitat associations of imperilled fishes after conservation intervention in the Cape Fold Ecoregion,South Africa

The aim of this study was to examine the habitat associations of a native cyprinid community of the recovering Rondegat River in the Cape Fold Ecoregion of South Africa as part of a long-term native fish abundance monitoring project. Relative abundance data were extracted from underwater video camera footage across the longitudinal gradient of the river in three sampling instances. Using multivariate methods the authors assessed community composition with respect to habitat, its overlap with a protected area and species-specific abiotic predictors of relative abundance. Distance from the uppermost site in the river was the most significant predictor of species abundance, indicating spatial segregation and varying overlap between species. The protected status of sites in the upper reaches, vegetated substrates and the size of individual sites were the most impactful on the relative abundance of the endangered fiery redfin Pseudobarbus phlegethon. The results of this study indicate that underwater video monitoring is an effective and low-cost approach that can inform conservation recommendations. Reducing agricultural runoff and sedimentation in the lower reaches may be useful further interventions to maintain key habitats of submerged vegetation.     

Habitat preferences of sub-montane spiders in northem England

Thirteen study sites were selected to cover the dominant vegetation types on the plateaux of three summits in the North Pennines, England The spider community of these sites were sampled by pitfall trapping between April and October 1991 Several environmental variables were collected for each site, including local topography, soil characteristics and vegetation structure Multivariate methods were used to classify the sites based on their spider species composition Canonical correspondence analysis was used to assess the influence of the external factors on the distribution of the species The results suggest that vegetation density is the major factor influencing spider distribution on the summit plateaux with slope and soil depth also contributing to the variation Three spider associations for the plateaux are proposed based on their common species composition Two short Festuca grassland assemblages and a Nardus/ Ertophorum spp assemblage associated with higher vegetation density The habitat preferences of some species common to the plateaux are discussed in light of the results, and compatisons are made with studies from other upland areas     

Habitat preference of the striped legless lizard: Implications of grazing by native herbivores and livestock for conservation of grassland biota

Across the globe, many species of reptile are threatened with extinction, with changes in grazing pressure as a significant factor in their decline. Few studies have investigated the role of native herbivores, yet studying natural grazers may provide insight into natural grazing regimes, not apparent in studies of domestic livestock. In this study, we investigate the habitat requirements of a threatened Australian grassland reptile, the striped legless lizard, Delma impar, in grasslands grazed by a native herbivore, the eastern grey kangaroo Macropus giganteus. Delma impar appears sensitive to habitat change resulting from altered grazing intensity, but a lack of information hinders implementation of appropriate grazing regimes. To address this gap, we investigated habitat preferences of D. impar at multiple spatial scales across a grazing gradient. We found that the occurrence of D. impar was not affected by the size of grassland remnants, but was negatively related to the density of native grazers. This result was likely a consequence of the negative effect of high grazing intensity on grass structural complexity, as the probability of encountering a D. impar was positively related to grass structural complexity at the fine scale (1 m²). We recommend that conservation efforts should avoid high intensity grazing (equivalent to > 1.3 kangaroos/ha), yet ensure enough grazing disturbance is maintained to promote the formation of complex grass structures. We also recommend that small floristically degraded and fragmented grassland habitat should be included in conservation efforts. These recommendations will likely benefit a number of faunal species in grasslands grazed by domestic and native grazers. Importantly, our data highlight the need for managing grazing regimes, even in environments dominated by native herbivores.     

Habitat associations of juvenile fish at Ningaloo Reef, Western Australia: the importance of coral and algae

Habitat specificity plays a pivotal role in forming community patterns in coral reef fishes, yet considerable uncertainty remains as to the extent of this selectivity, particularly among newly settled recruits. Here we quantified habitat specificity of juvenile coral reef fish at three ecological levels; algal meadows vs. coral reefs, live vs. dead coral and among different coral morphologies. In total, 6979 individuals from 11 families and 56 species were censused along Ningaloo Reef, Western Australia. Juvenile fishes exhibited divergence in habitat use and specialization among species and at all study scales. Despite the close proximity of coral reef and algal meadows (10's of metres) 25 species were unique to coral reef habitats, and seven to algal meadows. Of the seven unique to algal meadows, several species are known to occupy coral reef habitat as adults, suggesting possible ontogenetic shifts in habitat use. Selectivity between live and dead coral was found to be species-specific. In particular, juvenile scarids were found predominantly on the skeletons of dead coral whereas many damsel and butterfly fishes were closely associated with live coral habitat. Among the coral dependent species, coral morphology played a key role in juvenile distribution. Corymbose corals supported a disproportionate number of coral species and individuals relative to their availability, whereas less complex shapes (i.e. massive & encrusting) were rarely used by juvenile fish. Habitat specialisation by juvenile species of ecological and fisheries importance, for a variety of habitat types, argues strongly for the careful conservation and management of multiple habitat types within marine parks, and indicates that the current emphasis on planning conservation using representative habitat areas is warranted. Furthermore, the close association of many juvenile fish with corals susceptible to climate change related disturbances suggests that identifying and protecting reefs resilient to this should be a conservation priority.     

Low propensity for aerial dispersal in specialist spiders from fragmented landscapes

Aerial dispersal by ballooning is a passive flight, by which wind drag generates an upward lift on a silk thread. It is likely to reflect an aerial lottery, in which the absence of flight direction control is a serious cost for long-distance dispersal in a fragmented landscape. For species occurring in one patchily distributed habitat type, dispersal should evolve in a different way from morphological traits, directly linked to active dispersal. Therefore, we expect that if the risk of landing in an unsuitable habitat is lower than the probability of reaching a suitable habitat, selection should benefit a well-developed ballooning behaviour. We investigated interspecific variation in the ballooning-initiating tiptoe behaviour as it is linked to spider dispersal performance. Our results indeed indicate that ballooning performance is negatively related to habitat specialization in spiders from patchy grey dunes, so habitat specialists are characterized by poorly developed dispersal behaviour. These findings are concordant with recent insights that dispersal is selected as risk spreading in generalists, while it is selected against in specialist species.     

Monitoring fragile upland landscapes: The application of airborne lidar

This paper investigates the potential of airborne lidar for recording and monitoring erosion levels in environmentally fragile upland landscapes, using an area of the Brecon Beacons National Park as a case study. Upland areas contain a rich variety of natural and cultural resources that are increasingly endangered through factors such as insensitive land-use practices, improvements in recreational access and climate change. Airborne lidar provides a highly detailed record of microtopography, in this example at a resolution of 0.5 m with a vertical accuracy of c.0.15 m and the ability to differentiate elevation changes to within 1-2 cm. The technique therefore allows the rapid and cost-effective recording of the nature and extent of erosion at a landscape scale, with the results of this analysis recording over 46 kilometres of path erosion within a 3.8 km² area. The technique also provides the ability to highlight particular areas of risk, such as extensive braided erosion around path intersections and damage to protected SSSI habitats, providing a snapshot record of erosion at a particular point in time and an invaluable source of information for conservationists and policy-makers.     

Biogeography and conservation biology of Florida's Geolycosa wolf spiders: threatened spiders in endangered ecosystems

The state of Florida has a complex biogeography which is the product of past sea level changes and associated ocean currents creating numerous inland sand ridge systems which are home to a unique biota adapted to the seasonally dry conditions found on these sandy uplands. Among these xeric-adapted taxa is a suite of wolf spider species in the genus Geolycosa. Geolycosa wolf spiders are habitat specialists and poor dispersers, and many taxa have ranges restricted to specific ridge systems. We found that the six Geolycosa species typical of Florida's scrubs and sandhills (G. escambiensis Wallace, G. ornatipes (Bryant), G. micanopy Wallace, G. patellonigra Wallace, G. hubbelli Wallace and G. xera McCrone) have current distributions that correlate with the historical biogeography of the state. There are species typical of the Lake Wales Ridge and associated ridges (G. xera and G. hubbelli), species found on the more coastal ridges (G. patellonigra and G. micanopy) and species whose ranges are divided by the Apalachicola River drainage (G. escambiensis and G. ornatipes). We also found that Geolycosa wolf spiders tend to occur in species pairs which use different microhabitats: those which burrow in areas covered in leaf litter, and those which use only barren sites. These latter species require habitat management plans that include burns, that maintain the habitat in an open condition.     

Wetlands classification for amphibian conservation in Mediterranean landscapes

Habitat fragmentation and alteration have been described as the major factors relating to the decline observed in several amphibian species. In Spain, these processes are mainly associated with the large agricultural land area, the widespread use of toxic substances, and the agricultural practices used. All these aggressions affect wetlands and their watersheds, which are essential aquatic systems for many amphibian species. In an effort to discover where conservation and specific action plans could be more necessary, this study relates the amphibian richness in 28 representative Mediterranean wetlands to their characteristics and the activities carried out on their watershed. The required information considers diverse wetland variables. Our results show that watershed habitat heterogeneity is significantly positively correlated with amphibian richness, while the percentage of the watershed area devoted to olive cultivation is negatively correlated with it. The results allow us to classify wetlands according to their importance for amphibian conservation. Our results also show that 80% of the studied wetlands need specific action plans. Especially, more sustainable cultivation methods are required considering drastic changes in current agricultural practices. Finally, our data provides a baseline to understand future alterations due to agricultural practices.     

Multitrophic effects of nutrient addition in upland grassland

Although the effects of nutrient enhancement on aquatic systems are well documented, the consequences of nutritional supplements on soil food webs are poorly understood, and results of past research examining bottom-up effects are often conflicting. In addition, many studies have failed to separate the effects of nutrient enrichment and the physical effects of adding organic matter. In this field study, we hypothesised that the addition of nitrogen to soil would result in a trophic cascade, through detritivores (Collembola) to predators (spiders), increasing invertebrate numbers and diversity.Nitrogen and lime were added to plots in an upland grassland in a randomised block design. Populations of Collembola and spiders were sampled by means of pitfall traps and identified to species.Seventeen species of Collembola were identified from the nitrogen plus lime (N+L) and control plots. Species assemblage, diversity, richness, evenness and total number were not affected by nutrient additions. However, there was an increase in the number of Isotomidae juveniles and Parisotoma anglicana trapped in the N+L plots.Of the 44 spider species identified, over 80% were Linyphiidae. An effect on species assemblage from the addition of N+L to the plots was observed on two of the four sampling dates (July 2002 and June 2003). The linyphiid, Oedothorax retusus, was the only species significantly affected by the treatments and was more likely to be trapped in the control plots.The increased number of juvenile Collembola, and change in community composition of spiders, were consequences of the bottom-up effect caused by nutrient inputs. However, despite efforts to eliminate the indirect effects of nutrient inputs, a reduction in soil moisture in the N+L plots cannot be eliminated as a cause of the invertebrate population changes observed. Even so, this experiment was not confounded by the physical effects of habitat structure reported in most previous studies. It provides evidence of moderate bottom-up influences of epigeic soil invertebrate food webs and distinguishes between nutrient addition and plant physical structure effects. It also emphasises the importance of understanding the effects of soil management practices on soil biodiversity, which is under increasing pressure from land development and food production.     

Rotational fallows as overwintering habitat for grassland arthropods: the case of spiders in fen meadows

Regular mowing of grassland is often necessary for plant conservation, but uncut vegetation is needed by many arthropods for overwintering. This may lead to conflicting management strategies for plant and arthropod conservation. Rotational fallows are a possible solution. They provide a spatio-temporal mosaic of mown and unmown areas that may combine benefits to both plants and arthropods. We tested if rotational fallows enhance spider overwintering in fen meadows. Rotational fallows consisted of three adjoining strips 10 m wide and 35–50 m long. Each year, one of these strips was left unmown (fallow) in an alternating manner so that each strip was mown two out of three years. Spiders were sampled during spring with emergence traps in nine pairs of currently unmown fallow strips and completely mown reference plots. Fallows significantly enhanced orb-weavers (Araneidae), sac spiders (Clubionidae) and ground spiders (Gnaphosidae). However, only 4.7% of the total variation in community composition was attributable to fallows. Community variation was larger between landscapes (34.5%) and sites (38.2%). Also β diversity was much higher between landscapes (45 species) and sites (22 species) than between fallows and mown reference plots (10 species). We conclude that the first priority for spider conservation is to preserve as many fen meadows in different landscapes as possible. Locally, rotational fallows enhance overwintering of the above-mentioned spider families, which are sensitive to mowing in other grassland types as well. Thus, rotational fallows would probably foster spider conservation in a wide range of situations. However, stronger effects can be expected from larger and/or older fallow areas.