Biotic homogenization destabilizes ecosystem functioning by decreasing spatial asynchrony.

Our planet is facing significant changes of biodiversity across spatial scales. Although the negative effects of local biodiversity (α diversity) loss on ecosystem stability are well documented, the consequences of biodiversity changes at larger spatial scales, in particular biotic homogenization, that is, reduced species turnover across space (ß diversity), remain poorly known. Using data from 39 grassland biodiversity experiments, we examine the effects of ß diversity on the stability of simulated landscapes while controlling for potentially confounding biotic and abiotic factors. Our results show that higher ß diversity generates more asynchronous dynamics among local communities and thereby contributes to the stability of ecosystem productivity at larger spatial scales. We further quantify the relative contributions of α and ß diversity to ecosystem stability and find a relatively stronger effect of α diversity, possibly due to the limited spatial scale of our experiments. The stabilizing effects of both α and ß diversity lead to a positive diversity-stability relationship at the landscape scale. Our findings demonstrate the destabilizing effect of biotic homogenization and suggest that biodiversity should be conserved at multiple spatial scales to maintain the stability of ecosystem functions and services.

Livestock Grazing Shapes the Vegetation Structure and Subsequent Habitat Use by the Endangered Skipper Pyrgus ruralis lagunae (Lepidoptera: Hesperiidae).

Many species adapted to alpine and montane meadow ecosystems are at risk of extinction. The skipper Pyrgus ruralis lagunae Scott is a mountaintop butterfly restricted to San Diego County, CA, a federally listed endangered species, and is in imminent risk of extinction. Historically, P. r. lagunae was found in the Laguna and Palomar mountains. We did not detect the skipper in the Laguna Mountains, and the species has likely been extirpated from this area, which represents half of its historical range and is the type locality. We studied three populations on Palomar Mountain. Skippers primarily occupied areas close to creeks or in adjacent ravines at two nongrazed sites. The third site is grazed by cattle, and skippers were found close to the forest edge. At nongrazed locations, creek areas had higher cover of intermediate-height vegetation, more bare ground, and more flowers compared with unoccupied areas of the same meadow. The vegetation at occupied and unoccupied areas within the grazed meadow were similar. Even so, skippers occupied areas with more bare ground as well as greater species richness of flowering plants. A grazing exclosure was previously installed in an attempt to protect and enhance skipper habitat, but skippers did not use the dense grasslands that developed inside the exclosures. Contrary to the prevailing theory, protection from grazing did not improve skipper habitat. This illustrates how management based on inadequate biological information can hinder well-intentioned conservation efforts.

Remote Cameras Reveal Experimental Artifact in a Study of Seed Predation in a Semi-Arid Shrubland.

Granivorous animals may prefer to predate or cache seed of certain plant species over others. Multiple studies have documented preference for larger, non-native seed by granivores. To accomplish this, researchers have traditionally used indirect inference by relating patterns of seed removal to the species composition of the granivorous animal community. To measure seed removal, researchers present seed to granivorous animals in the field using equipment intended to exclude certain animal taxa while permitting access to others. This approach allows researchers to differentiate patterns of seed removal among various taxa (e.g., birds, small mammals, and insects); however, it is unclear whether the animals of interest are freely using the exclusion devices, which may be a hindrance to discovering the seed dishes. We used video observation to perform a study of seed predation using a custom-built, infrared digital camera and recording system. We presented native and non-native seed mixtures in partitioned Petri dishes both within and outside of exclusion cages. The exclusion cages were intended to allow entrance by rodent taxa while preventing entrance by rabbits and birds. We documented all seed removal visits by granivorous animals, which we identified to the genus level. Genera exhibited varying seed removal patterns based on seed type (native vs. non-native) and dish type (open vs. enclosed). We documented avoidance of the enclosed dishes by all but one rodent taxa, even though these dishes were intended to be used freely by rodents. This suggests that preference for non-native seed occurs differentially among granivorous animals in this system; however, interpretation of these nuanced results would be difficult without the benefit of video observation. When feasible, video observation should accompany studies using in situ equipment to ensure incorrect assumptions do not lead to inappropriate interpretation of results.

Anti-S1P Antibody as a Novel Therapeutic Strategy for VEGFR TKI-Resistant Renal Cancer.

PURPOSE: VEGFR2 tyrosine kinase inhibition (TKI) is a valuable treatment approach for patients with metastatic renal cell carcinoma (RCC). However, resistance to treatment is inevitable. Identification of novel targets could lead to better treatment for patients with TKI-naïve or -resistant RCC. EXPERIMENTAL DESIGN: In this study, we performed transcriptome analysis of VEGFR TKI-resistant tumors in a murine model and discovered that the SPHK-S1P pathway is upregulated at the time of resistance. We tested sphingosine-1-phosphate (S1P) pathway inhibition using an anti-S1P mAb (sphingomab), in two mouse xenograft models of RCC, and assessed tumor SPHK expression and S1P plasma levels in patients with metastatic RCC. RESULTS: Resistant tumors expressed several hypoxia-regulated genes. The SPHK1 pathway was among the most highly upregulated pathways that accompanied resistance to VEGFR TKI therapy. SPHK1 was expressed in human RCC, and the product of SPHK1 activity, S1P, was elevated in patients with metastatic RCC, suggesting that human RCC behavior could, in part, be due to overproduction of S1P. Sphingomab neutralization of extracellular S1P slowed tumor growth in both mouse models. Mice bearing tumors that had developed resistance to sunitinib treatment also exhibited tumor growth suppression with sphingomab. Sphingomab treatment led to a reduction in tumor blood flow as measured by MRI. CONCLUSIONS: Our findings suggest that S1P inhibition may be a novel therapeutic strategy in patients with treatment-naïve RCC and also in the setting of resistance to VEGFR TKI therapy.

Planning, implementing, and monitoring multiple-species habitat conservation plans.

PREMISE OF THE STUDY: Despite numerous recommendations for various aspects of the design and monitoring of habitat conservation plans, there remains a need to synthesize existing guidelines into a comprehensive scheme and apply it to real-world conservation programs. METHODS: We review tools for systematic conservation planning and elements for designing and implementing ecological monitoring in an adaptive management context. We apply principles of monitoring design to the San Diego Multiple Species Conservation Program (MSCP) in California, USA--one of the first multispecies habitat conservation plans, located in a landscape where high biodiversity and urban development converge. KEY RESULTS: Tools for spatial conservation planning are aimed to conserve biodiversity, often in the context of a limited budget. In practice, these methods may not accommodate legislative mandates, budgetary uncertainties, and the range of implementation mechanisms available across consortia of stakeholders. Once a reserve is implemented, the question becomes whether it is effective at conserving biodiversity, and if not, what actions are required to make it effective. In monitoring plan development, status and threats should be used to prioritize species and communities that require management action to ensure their persistence. Conceptual models documenting the state of knowledge of the system should highlight the main drivers affecting status and trends of species or communities. Monitoring strategies require scientifically justified decisions based on sampling, response, and data design. CONCLUSIONS: Because the framework illustrated here tackles multiple species, communities, and threats at the urban-wildland interface, it will have utility for ecosystem managers struggling to design monitoring programs.

Assessing and prioritizing ecological communities for monitoring in a regional habitat conservation plan.

In nature reserves and habitat conservation areas, monitoring is required to determine if reserves are meeting their goals for preserving species, ecological communities, and ecosystems. Increasingly, reserves are established to protect multiple species and communities, each with their own conservation goals and objectives. As resources are always inadequate to monitor all components, criteria must be applied to prioritize both species and communities for monitoring and management. While methods for prioritizing species based on endangerment or risk have been established, approaches to prioritizing ecological communities for monitoring are not well developed, despite a long-standing emphasis on communities as target elements in reserve design. We established guidelines based on four criteria derived from basic principles of conservation and landscape ecology--extent, representativeness, fragmentation, and endangerment--to prioritize communities in the San Diego Multiple Species Conservation Plan (MSCP). The MSCP was one of the first multiple-species habitat conservation areas established in California, USA, and it has a complex spatial configuration because of the patterns of surrounding land use, which are largely urbanized. In this case study, high priority communities for monitoring include coastal sage scrub (high endangerment, underrepresented within the reserve relative to the region, and moderately fragmented), freshwater wetlands, and coastal habitats (both have high fragmentation, moderate endangerment and representativeness, and low areal extent). This framework may be useful to other conservation planners and land managers for prioritizing the most significant and at-risk communities for monitoring.

Relationships between human disturbance and wildlife land use in urban habitat fragments.

Habitat remnants in urbanized areas typically conserve biodiversity and serve the recreation and urban open-space needs of human populations. Nevertheless, these goals can be in conflict if human activity negatively affects wildlife. Hence, when considering habitat remnants as conservation refuges it is crucial to understand how human activities and land uses affect wildlife use of those and adjacent areas. We used tracking data (animal tracks and den or bed sites) on 10 animal species and information on human activity and environmental factors associated with anthropogenic disturbance in 12 habitat fragments across San Diego County, California, to examine the relationships among habitat fragment characteristics, human activity, and wildlife presence. There were no significant correlations of species presence and abundance with percent plant cover for all species or with different land-use intensities for all species, except the opossum (Didelphis virginiana), which preferred areas with intensive development. Woodrats (Neotoma spp.) and cougars (Puma concolor) were associated significantly and positively and significantly and negatively, respectively, with the presence and prominence of utilities. Woodrats were also negatively associated with the presence of horses. Raccoons (Procyon lotor) and coyotes (Canis latrans) were associated significantly and negatively and significantly and positively, respectively, with plant bulk and permanence. Cougars and gray foxes (Urocyon cinereoargenteus) were negatively associated with the presence of roads. Roadrunners (Geococcyx californianus) were positively associated with litter. The only species that had no significant correlations with any of the environmental variables were black-tailed jackrabbits (Lepus californicus) and mule deer (Odocoileus hemionus). Bobcat tracks were observed more often than gray foxes in the study area and bobcats correlated significantly only with water availability, contrasting with results from other studies. Our results appear to indicate that maintenance of habitat fragments in urban areas is of conservation benefit to some animal species, despite human activity and disturbance, as long as the fragments are large.

Species prioritization for monitoring and management in regional multiple species conservation plans.

Successful conservation plans are not solely achieved by acquiring optimally designed reserves. Ongoing monitoring and management of the biodiversity in those reserves is an equally important, but often neglected or poorly executed, part of the conservation process. In this paper we address one of the first and most important steps in designing a monitoring program - deciding what to monitor. We present a strategy for prioritizing species for monitoring and management in multispecies conservation plans. We use existing assessments of threatened status, and the degree and spatial and temporal extent of known threats to link the prioritization of species to the overarching goals and objectives of the conservation plan. We consider both broad and localized spatial scales to capture the regional conservation context and the practicalities of local management and monitoring constraints. Spatial scales that are commensurate with available data are selected. We demonstrate the utility of this strategy through application to a set of 85 plants and animals in an established multispecies conservation plan in San Diego County, California, USA. We use the prioritization to identify the most prominent risk factors and the habitats associated with the most threats to species. The protocol highlighted priorities that had not previously been identified and were not necessarily intuitive without systematic application of the criteria; many high-priority species have received no monitoring attention to date, and lower-priority species have. We recommend that in the absence of clear focal species, monitoring threats in highly impacted habitats may be a way to circumvent the need to monitor all the targeted species.

Predicting obstructive coronary artery disease with serum sphingosine-1-phosphate.

BACKGROUND: Sphingolipids are emerging as important signaling molecules that may be produced by cardiac tissue during ischemic stress or as a consequence of inflammation. Because both inflammation and myocardial ischemia are associated with coronary artery disease (CAD), a study was designed to test the ability of serum sphingolipids to predict obstructive CAD. METHODS: The study consisted of 308 consecutive patients undergoing coronary angiography for all indications. The primary data points were the assessment of coronary artery stenosis with angiography and the measurements of serum sphingolipids. RESULTS: In this diverse population, serum sphingosine-1-phosphate (S1P) was a significant predictor of CAD (P <.001). Multivariate analysis with logistic regression demonstrated that serum S1P was more predictive of obstructive CAD (odds ratio = 7.61) than the traditional risk factors (age, sex, family history of CAD, diabetes mellitus, lipid profile, hypertension, etc.). A 3-variable S1PC composite score was derived by combining the power of the S1P marker with the 2 most important risk factors, age and sex. The relationship between the S1PC and CAD scores was continuous and progressive, such that patients with elevated S1PC scores had higher occurrences of obstructive CAD. S1PC was also predictive of disease severity; 53.2% of patients in the fourth S1PC quartile had 2 to 3 vessel CAD, whereas only 5.2% of patients in the first S1PC quartile had 2 to 3 vessel disease (RR = 10.2 for severity). CONCLUSIONS: Serum S1P is a remarkably strong and robust predictor of both the occurrence and severity of coronary stenosis. An S1P-based composite score may be useful as a novel, non-invasive indicator of obstructive CAD.