13 research outputs found
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The role of small private game reserves in leopard Panthera pardus and other carnivore conservation in South Africa
Many large carnivores are declining globally; most threatened or risk extinction due to a loss of habitat, resources, and direct removal; often the later as a result of conflict with humans. Although leopards and many meso-carnivore species are still free roaming in South Africa, few data are available on these species outside large protected areas as they are often elusive, wide ranging and found at low densities. More data are needed on the population dynamics, ecology and biology of species such as leopard, if we are to implement evidence-based approaches to their conservation within small reserves and surrounding unprotected areas.
Camera traps are being increasingly utilized in research, as they can record data on a species or a whole community at relatively low cost. Here we used a network of camera traps to monitor species presence at Thaba Tholo Wilderness Reserve, Mpumalanga, South Africa. We found that camera trap efficacy varied between species, with smaller carnivores significantly under-recorded more frequently than larger predators. However, leopards were successfully captured by camera trap when compared with more traditional monitoring methods (i.e. spoor).
Small reserves may play an important role in the conservation of carnivores, but often these reserves are surrounded by farmland and the successful separation of livestock and game using a fence can affect vegetation composition, fragmenting the land further. However, these effects may be limited by the free movement of wild browsers and grazers through holes in the fence which may also decrease the negative effects of fencing while supporting endangered and highly mobile species such as the leopard Panthera pardus.
Leopard densities were found to be 3.04 (S.E. +/-1.55) to 4.97 (S.E. +/-2.14) leopards per 100km2, which was lower than other estimates from South Africa, however the population was stable throughout the study suggesting the reserve was a source for leopard and offspring were dispersing. Although there was no evidence of habitat preference by the leopard, habitat was found to be more significant in influencing relative local abundances of meso-carnivores than potential associations with leopard and other larger carnivores. However abundance may have been affected by factors outside the reserve as conflict with humans was evident.
Negative actions towards leopard and other carnivores in retaliation to the predation of animal stock occurred in the farmland surrounding the study site, with a significantly higher percentage of commercial game farmers responding that they would take action against one or more species of carnivore compared to livestock owners. The financial loss sustained with increasing game prices in South Africa could therefore increase the conflict between humans and carnivores across the country, which in turn could have detrimental effects on local leopard and other carnivore populations.
The relatively high numbers of the extremely rare erythristic leopard occurring within the relatively low density leopard population is likely to be the result of genetic drift, which may have been a result of this conflict; highlighting that although small reserves may play an important role in the protection and propagation of threatened species it is human acceptance of carnivores which is likely to be vital in the successful conservation and long term survival of predators outside protected areas
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Meta-analysis suggests differing indirect effects of viral, bacterial, and fungal plant pathogens on the natural enemies of insect herbivores
Indirect effects are ubiquitous in nature, and have received much attention in terrestrial plant–insect herbivore–enemy systems. In such tritrophic systems, changes in plant quality can have consequential effects on the behavior and abundance of insect predators and parasitoids. Plant quality as perceived by insect herbivores may vary for a range of reasons, including because of infection by plant pathogens. However, plant diseases vary in their origin (viral, bacterial or fungal) and as a result may have differing effects on plant physiology. To investigate if the main groups of plant pathogens differ in their indirect effects on higher trophic levels, we performed a meta-analysis using 216 measured responses from 29 primary studies. There was no overall effect of plant pathogens on natural enemy traits as differences between pathogen types masked their effects. Infection by fungal plant pathogens showed indirect negative effects on the performance and preference of natural enemies via both chewing and piercing-sucking insect herbivore feeding guilds. Infection by bacterial plant pathogens had a positive effect on the natural enemies (parasitoids) of chewing herbivores. Infection by viral plant pathogens showed no clear effect, although parasitoid preference may be positively affected by their presence. It is important to note that given the limited volume of studies to date on such systems, this work should be considered exploratory. Plant pathogens are very common in nature, and tritrophic systems provide an elegant means to examine the consequences of indirect interactions in ecology. We suggest that further studies examining how plant pathogens affect higher trophic levels would be of considerable value
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Aphids show interspecific and intraspecific variation in life history responses to host plant infection by the fungal pathogen Botrytis cinerea
The life histories of insect herbivores are affected by variation in host plant quality, with poor quality typically being associated with reduced herbivore fecundity, size and longevity. Plant pathogens are ubiquitous in nature and can alter host plant quality as experienced by insect herbivores. We asked how host plant infection by the widespread and economically important fungal pathogen Botrytis cinerea affected the life history traits of two aphid species. We found that the life history traits of the black bean aphid Aphis fabae were negatively affected by being reared on infected host plants, showing reduced fecundity, population growth rate, size, off-plant survival time and development rate. In contrast, we found that pea aphids Acyrthosiphon pisum benetted from being reared on infected plants, and that the degree of benet varied between pea aphid clonal lines. This work suggests that the ecological and economic consequences of plant pathogen infection on the dynamics of aphid pests could be difcult to predict
Map-A-Mole: greenspace area influences the presence and abundance of the European mole Talpa europaea in urban habitats
The European mole Talpa europaea is common across much of Britain. It has a unique fossorial lifestyle, and evidence of its presence is readily identified through the presence of characteristic molehills. Although molehills are often a common sight in urban greenspaces, moles are remarkably understudied, with very few studies to date exploring the urban ecology of moles. Here, we investigate if factors such as greenspace (largely urban parks and playing fields) area, intensity of management, distance to nearest patch, amount of time the patch had been isolated from other green patches, and the amount of urbanization (constructed surfaces) surrounding the patch, influence the distribution and abundance of urban moles. Mole signs (hills and surface runs) were counted in all discrete urban greenspaces (excluding domestic gardens and one private golf course) within an 89.5 km2 area in the UK town of Reading. We found that 17 out of 59 surveyed sites contained moles, with their presence being recorded in greenspaces with a minimum patch area of approximately 0.1 km2 (10 ha). Where present, the abundance of mole territories in the greenspaces was associated with both the area of greenspace and degree of urbanization within 150 m of the patch boundary. While the former was not surprising, the latter outcome may be a consequence of sites with an increased risk of flooding being home to fewer moles, and the surrounding area is also less likely to be built upon. This case study highlights how choices made in designing urban green infrastructure will determine which species survive in urban areas long into the future
Game fence presence and permeability influences the local movement and distribution of South African mammals
Fences are utilized throughout the world to restrict the movements of wildlife, protecting them from threats and reducing human-wildlife conflict. In South Africa the number of privately-owned fenced game reserves has greatly increased in recent years, but little is known about how fencing affects the distribution and movements of target and non-target mammals. We surveyed 2m either side of the complete fence line of a recently established commercial game reserve in South Africa, identifying signs of animal presence (spoor, scat, foraging or other field signs) while also recording damage (holes) to the fence. Every 250m we carried out 100m perpendicular transects either side of the fence, recording vegetation cover and height at 10m intervals along the transect. We found that livestock (largely cattle) were excluded from the reserve. However, 12% of records of large animal species were recorded outside of the fence line. These species had been introduced to the reserve, strongly suggesting that they had crossed the boundary into the surrounding farmland. Sixteen naturally present wild species were found on both sides of the fence, but we found more evidence of their presence inside the reserve. Observational evidence suggests that they were regularly crossing the boundary, particularly where the fence was damaged, with hole size affecting species recorded. We also found evidence that the construction of the fence had led to a difference in vegetation structure with plant diversity and percentage of non-woody plant cover significantly higher inside the fence. While fencing was highly effective at preventing movement of livestock, introduced and wild animals were able to cross the boundary, via holes in the fence. This work shows that the efficacy of the most common approach to preventing animal movement around protected areas depends on the species being considered and fence condition
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Limitations to recording larger mammalian predators in savannah using camera traps and spoor
Traditionally, spoor (tracks, pug marks) have been used as a cost effective tool to assess the presence of larger mammals. Automated camera traps are now increasingly utilized to monitor wildlife, primarily as the cost has greatly declined and statistical approaches to data analysis have improved. While camera traps have become ubiquitous, we have little understanding of their effectiveness when compared to traditional approaches using spoor in the field. Here, we a) test the success of camera traps in recording a range of carnivore species against spoor; b) ask if simple measures of spoor size taken by amateur volunteers is likely to allow individual identification of leopards and c) for a trained tracker, ask if this approach may allow individual leopards to be followed with confidence in savannah habitat. We found that camera traps significantly under-recorded mammalian top and meso-carnivores, with camera traps more likely under-record the presence of smaller carnivores (civet 64%; genet 46%, Meller’s mongoose 45%) than larger (jackal sp. 30%, brown hyena 22%), while leopard was more likely to be recorded by camera trap (all recorded by camera trap only). We found that amateur trackers could be beneficial in regards to collecting presence data; however the large variance in measurements of spoor taken in the field by volunteers suggests that this approach is unlikely to add further data. Nevertheless, the use of simple spoor measurements in the field by a trained field researcher increases their ability to reliably follow a leopard trail in difficult terrain. This allows researchers to glean further data on leopard behaviour and habitat utilisation without the need for complex analysis
Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.
To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC
Significant benefits of AIP testing and clinical screening in familial isolated and young-onset pituitary tumors
Context
Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene are responsible for a subset of familial isolated pituitary adenoma (FIPA) cases and sporadic pituitary neuroendocrine tumors (PitNETs).
Objective
To compare prospectively diagnosed AIP mutation-positive (AIPmut) PitNET patients with clinically presenting patients and to compare the clinical characteristics of AIPmut and AIPneg PitNET patients.
Design
12-year prospective, observational study.
Participants & Setting
We studied probands and family members of FIPA kindreds and sporadic patients with disease onset ≤18 years or macroadenomas with onset ≤30 years (n = 1477). This was a collaborative study conducted at referral centers for pituitary diseases.
Interventions & Outcome
AIP testing and clinical screening for pituitary disease. Comparison of characteristics of prospectively diagnosed (n = 22) vs clinically presenting AIPmut PitNET patients (n = 145), and AIPmut (n = 167) vs AIPneg PitNET patients (n = 1310).
Results
Prospectively diagnosed AIPmut PitNET patients had smaller lesions with less suprasellar extension or cavernous sinus invasion and required fewer treatments with fewer operations and no radiotherapy compared with clinically presenting cases; there were fewer cases with active disease and hypopituitarism at last follow-up. When comparing AIPmut and AIPneg cases, AIPmut patients were more often males, younger, more often had GH excess, pituitary apoplexy, suprasellar extension, and more patients required multimodal therapy, including radiotherapy. AIPmut patients (n = 136) with GH excess were taller than AIPneg counterparts (n = 650).
Conclusions
Prospectively diagnosed AIPmut patients show better outcomes than clinically presenting cases, demonstrating the benefits of genetic and clinical screening. AIP-related pituitary disease has a wide spectrum ranging from aggressively growing lesions to stable or indolent disease course
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Urbanization and plant pathogen infection interact to affect the outcome of ecological interactions in an experimental multitrophic system
Urbanization can change interactions in insect communities, and the few studies of tritrophic interactions in urban settings focus on interactions between plants, herbivorous insects and their mutualists and natural enemies. Plant pathogen infection is also widespread and common, and infection may also alter such interactions, but we have no understanding of whether the ecological consequences of pathogen infection vary with urbanization. Using replicated aphid colonies on experimental plants, we investigated how infection by the plant pathogen Botrytis cinerea influences interactions between plants, aphids and the aphid natural enemies and ant mutualists in highly urbanized, suburban and rural study sites. Aphid and natural enemy abundance were highest in the suburban site, while mutualist ants were most abundant in the urban site, reversing the usual positive density-dependent relationship between natural enemies and aphids. The effect of pathogen infection varied with trait and site, mediated by natural enemy preference for hosts or prey on uninfected plants. The effect of infection on aphid abundance was only seen in the suburban site, where natural enemies were most abundant on uninfected plants and aphid numbers were greatest on infected plants. In the urban site, there was no effect of infection, while in the rural site, aphid numbers were lower on infected plants. Uninfected plants were smaller than infected plants and differed between locations. This study suggests that the effects of urbanization on ecological interactions may become more complex and difficult to predict as we study ecological assemblages and communities at greater levels of structural
complexity
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Pet cats (Felis catus) from urban boundaries use different habitats, have larger home ranges and kill more prey than cats from the suburbs
The domestic cat (Felis catus) is a predator of global significance. In Great Britain there are ca. 9.5 million owned pet cats, with their population determined by human population density. As urban areas expand and encroach on areas of conservation value, it is not known how cats use these areas and how habitat availability influences predation rates. To address this, over a year we recorded the movement and prey of 79 owned cats in inner suburban areas (non-boundary cats) and in areas adjacent to natural habitats on the edge of the suburban area (boundary cats). Boundary cats had larger home ranges (mean 3.42 S.E. ± 0.61 ha) and returned more prey (mean 7.91 S.E. ± 2.70 prey cat-1year−1) than cats in non-boundary areas (2.01 S.E. ± 0.70 ha; 3.35 S.E. ± 1.06 prey cat-1year-1respectively). Assuming a prey return rate of 23%, extrapolated predation rates equate to 34.40 (S.E. ± 11.74) and 14.57 (S.E. ± 4.62) prey cat-1year−1 in our boundary and suburban study sites respectively. While non-boundary cats had little access to natural habitats, natural habitats made up > 25% of the home range of boundary cats. Boundary cats travelled a mean distance of 64.9 m (S.E. ± 6.8) into these natural habitats, with some cats ranging > 300 m inside these areas. Bird predation rates did not differ between boundary and non-boundary cats, but boundary cats killed three times more mammals. This is of relevance to urban planning, as the hunting behaviour of pet cats extends the ecological effects of urbanisation into surrounding habitats