Adina M. Merenlender

Faunal indicator taxa selection for monitoring ecosystem health

Maintaining healthy ecosystems is a prerequisite for conserving biodiversity. The complex nature of ecosystems often necessitates the use of indicator taxa to monitor ecosystem health. However, ambiguous selection criteria and the use of inappropriate taxa have brought the utility of indicator taxa under question. This review compiles existing selection criteria from the literature, evaluates inconsistencies among these criteria, and proposes a step-wise selection process. In addition, 100 vertebrate and 32 invertebrate taxa documented in the conservation science literature as indicators of ecosystem health are examined to assess how well they adhere to the referenced criteria. Few vertebrate taxa fulfill multiple criteria, as most are highly mobile generalists that lack established tolerance levels and correlations with ecosystem changes. Most suggested invertebrate taxa also lack correlations to ecosystem changes, but satisfy other selection criteria. However, invertebrate taxa are often suggested at high taxonomic levels, encompassing many species, making it diAcult to measure specific attributes, and potentially including many unnecessary and even inappropriate species. # 2000 Elsevier Science Ltd. All rights reserved.

Habitat and Open Space at Risk of Land-Use Conversion: Targeting Strategies for Land Conservation

Funds available to purchase land and easements for conservation purposes are limited. This article provides a targeting strategy for protecting multiple environmental benefits that includes heterogeneity in land costs and probability of land-use conversion, by incorporating spatially explicit land-use change and hedonic price models. This strategy is compared to two alternative strategies that omit either land cost or conversion threat. Based on dynamic programming and Monte Carlo simulations with alternating periods of conservation and development, we demonstrate that the positive correlation between land costs and probability of land-use conversion affects targeting efficiency using parcel data from Sonoma County, California.

Life history of Eulemur fulvus rufus from 1988-1998 in southeastern Madagascar.

In this study, we compare the life-history patterns of male and female Eulemur fulvus rufus based on longitudinal data collected on individuals from two study groups from 1988-1998 in southeastern Madagascar. Mean group size was 9.5 individuals, and groups either contained more adult males than females or equal numbers of both sexes. Females reproduced for the first time between 2 and 4 years of age and reproduced each year, although the mean interbirth interval between surviving offspring was 2.1 years. An average of two adult females reproduced annually in each social group, and age and body weight may positively influence reproductive success. Females also appear to be philopatric but not female-bonded. Young natal males immigrated between 3 and 4.5 years of age and may join a new group within 612 months based on the age of emigrants. Once in a social group, they remained until old age, although a males spatial position in the social group varied with age. Young nonnatal males were members of the social core and had the first opportunity to mate with all estrous females. Older males were peripheral to the social group and mated with females later in their cycle. We hypothesize that group size, the number of females in the group, and individual variation in reproductive success is influenced by several ecological conditions at this site: extreme variability in food availability during reproductive periods, the lack of large food patches, low plant species diversity, and small numbers of important aseasonal food sources such as Ficus species.

The Role of Streamflow and Land Use in Limiting Oversummer Survival of Juvenile Steelhead in California Streams

Abstract Increasing human pressures on freshwater resources have led to global declines in fish populations and have made the protection of instream flows critical to the conservation of riverine ecosystems. However, uncertainty in predicting ecological responses to flow variability has hindered implementation of successful environmental flow management. An improved understanding of the relationships between streamflows and Pacific salmon Oncorhynchus spp. population persistence is particularly needed in semiarid regions such as California, where streamflows during the dry season are highly variable and increasingly threatened by withdrawals to meet human water demands. To examine the effects of summer low flows on a threatened salmonid species, we analyzed 9 years of count data for juvenile steelhead O. mykiss from nine stream reaches in four coastal California watersheds. We used a Bayesian modeling framework to examine the relative influences of streamflow, land use, and habitat quality on juvenile ste...

The Effectiveness of Riparian Restoration for Improving Instream Fish Habitat in Four Hardwood-Dominated California Streams

Abstract Recent reviews of salmonid habitat restoration programs have recommended that managers emphasize strategies that restore natural habitat-forming processes, such as restoring riparian vegetation, over placement of instream structures. In addition to the direct benefits of shading and providing a source for large woody debris (LWD), riparian restoration is often implemented to improve channel morphology for purposes of restoring fish habitat. However, multiple studies provide equivocal evidence that restored vegetation can lead to improved channel form within a period of years to decades. In this study, we examined the effectiveness of riparian restoration for improving channel morphology and fish habitat in four hardwood-dominated streams in Mendocino County, California. These streams support populations of steelhead Oncorhynchus mykiss and contain reaches with riparian corridors that were restored through exclusionary fencing implemented 10–20 years earlier. We compared channel morphology, LWD, a...

Forecasting relative impacts of land use on anadromous fish habitat to guide conservation planning.

Land use change can adversely affect water quality and freshwater ecosystems, yet our ability to predict how systems will respond to different land uses, particularly rural-residential development, is limited by data availability and our understanding of biophysical thresholds. In this study, we use spatially explicit parcel-level data to examine the influence of land use (including urban, rural-residential, and vineyard) on salmon spawning substrate quality in tributaries of the Russian River in California. We develop a land use change model to forecast the probability of losses in high-quality spawning habitat and recommend priority areas for incentive-based land conservation efforts. Ordinal logistic regression results indicate that all three land use types were negatively associated with spawning substrate quality, with urban development having the largest marginal impact. For two reasons, however, forecasted rural-residential and vineyard development have much larger influences on decreasing spawning substrate quality relative to urban development. First, the land use change model estimates 10 times greater land use conversion to both rural-residential and vineyard compared to urban. Second, forecasted urban development is concentrated in the most developed watersheds, which already have poor spawning substrate quality, such that the marginal response to future urban development is less significant. To meet the goals of protecting salmonid spawning habitat and optimizing investments in salmon recovery, we suggest investing in watersheds where future rural-residential development and vineyards threaten high-quality fish habitat, rather than the most developed watersheds, where land values are higher.

The Conservation Contributions of Conservation Easements: Analysis of the San Francisco Bay Area Protected Lands Spatial Database

Conservation easements have emerged as an important tool for land trusts and government agencies aiming to conserve private land in the United States. Despite the increase in public investment in conservation easement acquisitions, little is known about their conservation outcomes, particularly at a landscape scale. The nine-county San Francisco Bay Area exemplifies a complex conservation context: 190 organizations hold 24% of the land base in some type of protection status. Using a detailed protected lands database, we compared the contributions of conservation easements and fee-simple protected areas to ecological, agricultural, and public recreation benefits. We found that conservation easements were more likely to conserve grasslands, oak woodlands, and agricultural land, whereas fee-simple properties were more likely to conserve chaparral and scrub, redwoods, and urban areas. Conservation easements contributed to open space connectivity but were unlikely to be integrated into local land-use plans or provide public recreation. In particular, properties held by land trusts were less likely to allow for public recreation than were public lands. Conservation easements held by land trusts and special districts complemented fee-simple lands and provided greater conservation of some ecological communities and agricultural lands than fee-simple properties. Spatial databases of protected areas that include conservation easements are necessary for conservation planning and assessment.

Effects of Management of Domestic Dogs and Recreation on Carnivores in Protected Areas in Northern California

In developed countries dogs (Canis lupus familiaris) are permitted to accompany human visitors to many protected areas (e.g., >96% of protected lands in California, U.S.A.), and protected-area management often focuses on regulating dogs due to concerns about predation, competition, or transmission of disease and conflicts with human visitors. In 2004 and 2005, we investigated whether carnivore species richness and abundance were associated with management of domestic dogs and recreational visitation in protected areas in northern California. We surveyed for mammalian carnivores and human visitors in 21 recreation areas in which dogs were allowed offleash or onleash or were excluded, and we compared our observations in the recreation areas with observations in seven reference sites that were not open to the public. Carnivore abundance and species richness did not differ among the three types of recreation areas, but native carnivore species richness was 1.7 times greater (p < 0.01) and the relative abundances of native coyotes (Canis latrans) and bobcats (Lynx rufus) were over four times greater (p < 0.01) in the reference sites. Abundances of bobcats and all carnivores declined as the number of visitors increased. The policy on domestic dogs did not appear to affect species richness and abundance of mammalian carnivores. But the number of dogs we observed was strongly associated with human visitation (R(2) = 0.54), so the key factors associated with recreational effects on carnivores appear to be the presence and number of human visitors to protected areas.

Forecasting the effect of land-use change on native and non-native mammalian predator distributions

Intensive land use can fragment continuous natural areas into smaller patches, which may be too small to support viable populations of native fauna and more susceptible to invasion by alien species. We demonstrate the utility of combining species occurrence models with land-use change models to identify areas where future development may differentially affect wildlife. Occurrence data for native (e.g., gray fox, coyote, bobcat, mountain lion, striped skunk, raccoon) and non-native (e.g., domestic dogs, domestic cats, opossums) mammalian predators were collected from 188 remotely triggered camera locations across an oak woodland and vineyard landscape in northern California. The occurrence data were used in combination with landscape variables extracted using a geographic information system to build explanatory models of predator occurrence. These statistical models were used to derive two surfaces showing relative probability of occurrence for non-native and native predators. Then, a spatially explicit land-use change model was used to examine potential future predator distributions given potential future vineyard expansion. The probability distribution models generated hypothesized low probabilities of occurrence for native predators within large vineyard blocks, but higher probabilities within isolated vineyards and also in oak woodlands. The models suggest the highest probabilities of non-native predator occurrence fell within large blocks of vineyard. Using one possible future vineyard development scenario, the distribution models illustrate areas where probability of native predator occurrence may be reduced and where non-native predators may expand due to vineyard development. This technique could be applied to prioritize acquisition of critical wildlife habitat and maintain habitat connectivity for wildlife populations.

Effects of Recreation on Animals Revealed as Widespread through a Global Systematic Review

Outdoor recreation is typically assumed to be compatible with biodiversity conservation and is permitted in most protected areas worldwide. However, increasing numbers of studies are discovering negative effects of recreation on animals. We conducted a systematic review of the scientific literature and analyzed 274 articles on the effects of non-consumptive recreation on animals, across all geographic areas, taxonomic groups, and recreation activities. We quantified trends in publication rates and outlets, identified knowledge gaps, and assessed evidence for effects of recreation. Although publication rates are low and knowledge gaps remain, the evidence was clear with over 93% of reviewed articles documenting at least one effect of recreation on animals, the majority of which (59%) were classified as negative effects. Most articles focused on mammals (42% of articles) or birds (37%), locations in North America (37.7%) or Europe (26.6%), and individual-level responses (49%). Meanwhile, studies of amphibians, reptiles, and fish, locations in South America, Asia, and Africa, and responses at the population and community levels are lacking. Although responses are likely to be species-specific in many cases, some taxonomic groups (e.g., raptors, shorebirds, ungulates, and corals) had greater evidence for an effect of recreation. Counter to public perception, non-motorized activities had more evidence for a negative effect of recreation than motorized activities, with effects observed 1.2 times more frequently. Snow-based activities had more evidence for an effect than other types of recreation, with effects observed 1.3 times more frequently. Protecting biodiversity from potentially harmful effects of recreation is a primary concern for conservation planners and land managers who face increases in park visitation rates; accordingly, there is demand for science-based information to help solve these dilemmas.