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The historical area of bottomland hardwood forest in the Mississippi Alluvial Valley has been reduced by >75%. Agricultural production was the primary motivator for deforestation; hence, clearing deliberately targeted higher and drier sites. Remaining forests are highly fragmented and hydrologically altered, with larger forest fragments subject to greater inundation, which has negatively affected many forest bird populations. We developed a spatially explicit decision support model, based on a Partners in Flight plan for forest bird conservation, that prioritizes forest restoration to reduce forest fragmentation and increase the area of forest core (interior forest >1 km from 'hostile' edge). Our primary objective was to increase the number of forest patches that harbor >2000 ha of forest core, but we also sought to increase the number and area of forest cores >5000 ha. Concurrently, we targeted restoration within local (320 km2) landscapes to achieve >60% forest cover. Finally, we emphasized restoration of higher-elevation bottomland hardwood forests in areas where restoration would not increase forest fragmentation. Reforestation of 10% of restorable land in the Mississippi Alluvial Valley (approximately 880,000 ha) targeted at priorities established by this decision support model resulted in approximately 824,000 ha of new forest core. This is more than 32 times the amount of core forest added through reforestation of randomly located fields (approximately 25,000 ha). The total area of forest core (1.6 million ha) that resulted from targeted restoration exceeded habitat objectives identified in the Partners in Flight Bird Conservation Plan and approached the area of forest core present in the 1950s.
Connectivity is a measure of how landscape features facilitate movement and thus is an important factor in species persistence in a fragmented landscape. The scarcity of empirical studies that directly quantify species movement and determine subsequent effects on population density have, however, limited the utility of connectivity measures in conservation planning. We undertook a 4-year study to calculate connectivity based on observed movement rates and movement probabilities for five age-sex classes of painted turtles (Chrysemys picta) inhabiting a pond complex in an agricultural landscape in northern Virginia (U.S.A.). We determined which variables influenced connectivity and the relationship between connectivity and subpopulation density. Interpatch distance and quality of habitat patches influenced connectivity but characteristics of the intervening matrix did not. Adult female turtles were more influenced by the habitat quality of recipient ponds than other age-sex classes. The importance of connectivity on spatial population dynamics was most apparent during a drought. Population density and connectivity were low for one pond in a wet year but dramatically increased as other ponds dried. Connectivity is an important component of species persistence in a heterogeneous landscape and is strongly dependent on the movement behavior of the species. Connectivity may reflect active selection or avoidance of particular habitat patches. The influence of habitat quality on connectivity has often been ignored, but our findings highlight its importance. Conservation planners seeking to incorporate connectivity measures into reserve design should not ignore behavior in favor of purely structural estimates of connectivity.
Given their physiological requirements, limited dispersal abilities, and hydrologically sensitive habitats, amphibians are likely to be highly sensitive to future climatic changes. We used three approaches to map areas in the western hemisphere where amphibians are particularly likely to be affected by climate change. First, we used bioclimatic models to project potential climate-driven shifts in the distribution of 413 amphibian species based on 20 climate simulations for 2071–2100. We summarized these projections to produce estimates of species turnover. Second, we mapped the distribution of 1099 species with restricted geographic ranges. Finally, using the 20 future climate-change simulations, we mapped areas that were consistently projected to receive less seasonal precipitation in the coming century and thus were likely to have altered microclimates and local hydrologies. Species turnover was projected to be highest in the Andes Mountains and parts of Central America and Mexico, where, on average, turnover rates exceeded 60% under the lower of two emissions scenarios. Many of the restricted-range species not included in our range-shift analyses were concentrated in parts of the Andes and Central America and in Brazil's Atlantic Forest. Much of Central America, southwestern North America, and parts of South America were consistently projected to experience decreased precipitation by the end of the century. Combining the results of the three analyses highlighted several areas in which amphibians are likely to be significantly affected by climate change for multiple reasons. Portions of southern Central America were simultaneously projected to experience high species turnover, have many additional restricted-range species, and were consistently projected to receive less precipitation. Together, our three analyses form one potential assessment of the geographic vulnerability of amphibians to climate change and as such provide broad-scale guidance for directing conservation efforts.
Prior to 2001, seed predation was virtually absent in the endemic Wiliwili Erythrina sandwicensis (Fabaceae: Degener), dominant tree species of lower-elevation Hawaiian dryland forests. The African bruchine chrysomelid Specularius impressithorax (Pic) (Coleoptera: Chrysomelidae: Bruchinae) was first detected in Hawai'i in 2001 and became established on all main islands within the next two years. The mode of entry for this invasive Erythrina seed predator into Hawai'i is unknown, but likely occurred with the importation of trinket jewelry from Africa containing characteristically brightly-colored Erythrina seeds. The initial establishment of this insect likely occurred on a non-native host, the widely cultivated coral tree E. variegata. Within three years of its first record, S. impressithorax accounted for 77.4% mean seed crop loss in 12 populations of Wiliwili on six main Hawaiian islands. Specularius impressithorax, dispersed through international commerce and established via E. variegata, has become a threat to a unique Hawaiian forest type and may threaten other Erythrina, especially New World representatives.
Introduced avian diseases pose a significant threat to forest birds on isolated island archipelagos, especially where most passerines are endemic and many groups of blood-sucking arthropods are either absent or only recently introduced. We conducted a blood parasite survey of forest birds from the main islands of American Samoa to obtain baseline information about the identity, distribution and prevalence of hematozoan parasites in this island group. We examined Giemsa-stained blood smears from 857 individual birds representing 20 species on Tutuila, Ofu, Olosega, and Ta'u islands. Four hematozoan parasites were identified - Plasmodium circumflexum (1%, 12/857), Trypanosoma avium (4%, 32/857), microfilaria (9%, 76/857), and an Atoxoplasma sp. (<1%, 2/857). Infections were found in seven indigenous bird species from the archipelago. Overall prevalence of infection varied significantly among bird species, individual islands, and between Tutuila and the more isolated Manu'a group of islands. Infections with Plasmodium, Trypanosoma, and filarial worms occurred throughout the archipelago, including islands without introduced birds. There was a statistically significant difference in the overall prevalence of infection before and after Hurricane Olaf in February 2005, suggesting that catastrophic hurricanes may influence the dynamics of parasite infections. Given the central location of American Samoa in the South Pacific, it is likely that avian malaria and other hematozoan parasites are indigenous and widespread at least as far as the central South Pacific. Their natural occurrence may provide some immunological protection to indigenous birds in the event that other closely related parasites are accidentally introduced to the region.
Effective control of introduced mammalian predators is essential to the recovery of native bird species in Hawai'i. Between August 1996 and December 2004, introduced rodents were controlled within three home ranges of the Po'ouli Melamprosops phaeosoma, a critically endangered Hawaiian honeycreeper. Rats were controlled using a combination of ground-based rodenticide (0.005% diphacinone) application and snap traps. Beginning in August 2001, we monitored the effectiveness of these rodent control efforts. Relative abundances of Black Rats Rattus rattus and Polynesian Rats R. exulans were measured in each of five snap-trapping grids seven times over a 35-month period. Rat populations decreased inside of the rodent control areas, but control effectiveness differed between rat species. During the first year of monitoring, target control levels for R. rattus were consistently achieved in only one of the rodent control areas. Control techniques were refined in areas failing to meet targets. Subsequently, we achieved target control levels for R. rattus more consistently in all three rodent control areas. However, relative abundances of R. exulans did not differ between rodent control and reference areas, indicating that our rodent control techniques were insufficient to reduce population levels of this species. These findings signify a need for further improvement of rodent control methods in Hawai'i, especially for Polynesian Rats, and demonstrate the critical importance of periodic monitoring of the response of rodent populations to management. In the future, managers may need to design rodent control operations targeting R. rattus and R. exulans independently to achieve best results.
Feral cats (Felis cafus) have long been implicated as nest predators of endangered 'Ua'u (Hawaiian Petrel; Pterodroma sandwichensis) on Hawaii Island, but until recently, visual confirmation has been limited by available technology. 'Ua'u nest out of view, deep inside small cavities, on alpine lava flows. During the breeding seasons of 2007 and 2008, we monitored known burrows within Hawai'i Volcanoes National Park. Digital infrared video cameras assisted in determining the breeding behaviour and nesting success at the most isolated of burrows. With 7 cameras, we collected a total of 819 videos and 89 still photographs of adult and nestling 'Ua'u at 14 burrows. Videos also confirmed the presence of rats (Rattus spp.) at 2 burrows, 'Ōmao (Myadestes obscurus) at 8 burrows, and feral cats at 6 burrows. A sequence of videos showed a feral cat taking a downy 'Ua'u chick from its burrow, representing the first direct evidence of 'Ua'u depredation by feral cat in Hawai'i. This technique provides greater understanding of feral cat behaviour in 'Ua'u colonies, which may assist in the development of more targeted management strategies to reduce nest predation on endangered insular bird species.
The Sacramento-San Joaquin River Delta region of California (hereafter, Delta region) is an important wintering region for the Central Valley Population of greater sandhill cranes ( Grus canadensis tabida ) and lesser sandhill cranes ( G. c. canadensis ), but basic information about the ecology of these birds is lacking to design a biologically sound conservation strategy. During the winters of 2007-08 and 2008-09, we conducted roost counts, roadside surveys, aerial surveys, and tracked radio-marked birds to define the geographic area used by sandhill cranes in the Delta region, document migration chronology, and estimate subspecies-specific abundance. Radio-marked sandhill cranes arrived in our study area beginning 3 October, most arrived in mid-October, and the last radio-marked sandhill crane arrived on 10 December. Departure dates ranged from 15 January to 13 March. Mean arrival and departure dates were similar between subspecies. From mid-December through early-February in 2007-2008, the Delta population ranged from 20,000 to 27,000 sandhill cranes. Abundance varied at the main roost sites during winter because sandhill cranes responded to changes in water conditions. Sandhill cranes used an area of approximately 1,500 km 2 for foraging. Estimated peak abundance in the Delta region was more than half the total number counted on recent Pacific Flyway midwinter surveys, indicating the Delta region is a key area for efforts in conservation and recovery of wintering sandhill cranes in California. Based on arrival dates, flooding of sandhill crane roost sites should be staggered with some sites flooded in early September and most sites flooded by early October. Maintained flooding through mid-March would provide essential roosting habitat until most birds have departed the Delta region on spring migration.
Three subspecies of Spotted Bass Micropterus punctulatus were historically recognized: the smaller Northern Spotted Bass M. p. punctulatus , the larger, longer-lived Alabama Spotted Bass M. p. henshalli , and the now invalidated Wichita Spotted Bass M. p. wichitae (Bailey and Hubbs 1940; Cofer 1995; Warren 2009; Rider and Maceina 2015, this volume). The subspecific status has been examined over the past decade as advanced genetic analyses have been developed (e.g., Kassler et al. 2002; Baker et al. 2008; Tringali et al. 2015, this volume). The American Fisheries Society has recently changed the designation of the Alabama Spotted Bass to a separate species, Alabama Bass M. henshalli (Page et al. 2013). The remainder of this paper will discuss the biology and conservation of only Spotted Bass. Both species have been observed to hybridize with other Micropterus spp. (Koppelman 1994; Pierce and Van Den Avyle 1997; Barwick et al. 2006).
Bats are ecologically and economically important mammals. The life histories of bats (particularly their low reproductive rates and the need for some species to gather in large aggregations at limited numbers of roosting sites) make their populations vulnerable to declines. Many of the species of bats in the United States (U.S.) and territories are categorized as endangered or threatened, have been candidates for such categories, or are considered species of concern. The importance and vulnerability of bat populations makes monitoring trends in their populations a goal for their future management. However, scientifically rigorous monitoring of bat populations requires well-planned, statistically defensible efforts. This volume reports findings of an expert workshop held to examine the topic of monitoring populations of bats. The workshop participants included leading experts in sampling and analysis of wildlife populations, as well as experts in the biology and conservation of bats. Findings are reported in this volume under two sections. Part I of the report presents contributed papers that provide overviews of past and current efforts at monitoring trends in populations of bats in the U.S. and territories. These papers consider current techniques and problems, and summarize what is known about the status and trends in populations of selected groups of bats. The contributed papers in Part I also include a description of the monitoring program developed for bat populations in the United Kingdom, a critique of monitoring programs in wildlife in general with recommendations for survey and sampling strategies, and a compilation and analysis of existing data on trends in bats of the U.S. and territories. Efforts directed at monitoring bat populations are piecemeal and have shortcomings. In Part II of the report, the workshop participants provide critical analyses of these problems and develop recommendations for improving methods, defining objectives and priorities, gaining mandates, and enhancing information exchange to facilitate future efforts for monitoring trends in U.S. bat populations.
The U.S. Fish and Wildlife Service's adoption of Strategic Habitat Conservation is intended to increase the effectiveness and efficiency of conservation delivery by targeting effort in areas where biological benefits are greatest. Conservation funding has not often been allocated in accordance with explicit biological endpoints, and the gap between conservation design (the identification of conservation priority areas) and delivery needs to be bridged to better meet conservation goals for multiple species and landscapes. We introduce a regional prioritization scheme for North American Wetlands Conservation Act funding which explicitly addresses Midwest regional goals for wetland-dependent birds. We developed decision-support maps to guide conservation of breeding and non-breeding wetland bird habitat. This exercise suggested ~55% of the Midwest consists of potential wetland bird habitat, and areas suited for maintenance (protection) were distinguished from those most suited to restoration. Areas with greater maintenance focus were identified for central Minnesota, southeastern Wisconsin, the Upper Mississippi and Illinois rivers, and the shore of western Lake Erie and Saginaw Bay. The shores of Lakes Michigan and Superior accommodated fewer waterbird species overall, but were also important for wetland bird habitat maintenance. Abundant areas suited for wetland restoration occurred in agricultural regions of central Illinois, western Iowa, and northern Indiana and Ohio. Use of this prioritization scheme can increase effectiveness, efficiency, transparency, and credibility to land and water conservation efforts for wetland birds in the Midwestern United States.
The iconic forest birds of Hawai‘i are facing a conservation crisis. Across the Hawaiian Islands, native forest birds have been experiencing population declines that have accelerated in the last one to two decades. While habitat loss, invasive species, and non-native predators have negatively affected forest bird species for hundreds of years, and continue to do so, introduced diseases, particularly avian malaria, are the greatest threat to forest birds today. Further, climate change has increased temperatures in the high-elevation forests, facilitating the spread of disease into areas that were once largely disease-free. Rapid population declines have now (2022) pushed four Hawaiian honeycreeper species to the brink of extinction: the endangered ‘akikiki ( Oreomystis bairdi ) and ‘akeke‘e ( Loxops caeruleirostris ) on Kaua‘i Island, and kiwikiu ( Pseudonestor xanthophrys ) and ‘ākohekohe ( Palmeria dolei ) on Maui Island. The biologists that study these birds strongly agree that without a rapid conservation response to the threat of increasing disease mortality there is a high probability these species will go extinct in the coming decade. To help evaluate alternative conservation strategies for minimizing the risk of extinction, we convened diverse groups of experts with broad experience in Hawai‘i forest birds and ecosystems, as well as the management approaches being considered, to assess the probability of success of alternative management actions. In addition to assessing this crisis from a biological perspective, we convened a group of Native Hawaiian participants that have a strong connection to the forest birds, forests, and the integration of their culture in natural and biocultural resource management. They give voice to the significance of forest birds to Native Hawaiians and provide their perspectives on alternative management actions. Broadly, the three alternative management actions being considered to prevent the extinction of forest birds from the increasing threat of disease are (1) landscape-level mosquito control through the Wolbachia incompatible insect technique, (2) captive care, and (3) conservation translocations. The two key components of the problem of preventing extinction in these four bird species is time and risk. For each species, very few individuals remain, and they are all in danger of imminent extinction. Each management action takes time to implement, which might exceed the actual time to extinction. Additionally, each of these conservation actions has potential benefits and inherent risks, as well as substantial uncertainty in terms of being successful. Native Hawaiian perspectives and considerations also vary across the conservation actions. The expert evaluations summarized in this report provide a broad assessment of conservation strategies that could be undertaken to prevent the extinction of ‘akikiki, ‘akeke‘e, kiwikiu, and ‘ākohekohe. While this report does not recommend specific actions, the information is intended to support decision-makers as they assess which, if any, conservation strategies to pursue.
No abstract available.
One of only two native, freshwater turtle species in the western United States, western pond turtles are declining in portions of their original range. Declines are mostly due to habitat loss, introduction of non-native species, pollution, and lack of connectivity among populations. USGS zoologist R. Bruce Bury and colleagues from the U.S. Forest Service, California State University, and other agencies compiled and edited a new review and field manual of this charismatic species. Objectives were to determine its current distribution and abundance, summarize and evaluate population features, review techniques to detect population and habitat changes, and improve monitoring for long-term trends. Methods described in the manual should improve consistency, efficiency, and accuracy of survey data, resulting in improved management and conservation efforts.
Integration of conservation partnerships across geographic, biological, and administrative boundaries is increasingly relevant because drivers of change, such as climate shifts, transcend these boundaries. We explored successes and challenges of established conservation programs that span multiple watersheds and consider both social and ecological concerns. We asked representatives from a diverse set of 11 broadextent conservation partnerships in 29 countries 17 questions that pertained to launching and maintaining partnerships for broad-extent conservation, specifying ultimate management objectives, and implementation and learning. Partnerships invested more funds in implementing conservation actions than any other aspect of conservation, and a program’s context (geographic extent, United States vs. other countries, developed vs. developing nation) appeared to substantially affect program approach. Despite early successes of these organizations and benefits of broad-extent conservation, specific challenges related to uncertainties in scaling up information and to coordination in the face of diverse partner governance structures, conflicting objectives, and vast uncertainties regarding future system dynamics hindered long-term success, as demonstrated by the focal organizations. Engaging stakeholders, developing conservation measures, and implementing adaptive management were dominant challenges. To inform future research on broad-extent conservation, we considered several challenges when we developed detailed questions, such as what qualities of broad-extent partnerships ensure they complement, integrate, and strengthen, rather than replace, local conservation efforts and which adaptive management processes yield actionable conservation strategies that account explicitly for dynamics and uncertainties regarding multiscale governance, environmental conditions, and knowledge of the system?
A text devoted to the biology and ecology of marine birds has not been published in the last 15 years. Although a number of more taxa-specific texts have been produced during that period, there has not been a single publication that attempted to review our knowledge of all the major seabird orders since the works of Nelson (1979), Croxall (1987), and Furness and Monaghan (1987). Following the publication of those works, a large and impressive body of literature has been produced. Given the rapid expansion of the field in the last two decades, the time was ripe for production of an extensive compendium on the biology, ecology, and conservation of the world's seabirds. E. A. Schreiber and J. Burger are editors of this CRC publication, Biology of Marine Birds . The book consists of 19 chapters that vary in length from 15 to 51 pages. There are also two extensive appendices: (1) a list of seabird species (restricted to the orders Sphenisciformes, Procellariiformes, Pelecaniformes, and Charadriiformes, the latter limited to Stercorariidae, Laridae, Rhynchopidae, and Alcidae) and their IUCN status, and (2) a very useful table of species-specific life-history traits. The 19 chapters were prepared by 26 authors, among them some of the most respected and published seabird scientists in the world. A brief preface introduces the book, its objective (to provide an examination and summary of the research on seabirds), its audience (researchers, conservationists, managers, and policy-makers), and the taxa covered. The editors coauthored the introductory chapter, Seabirds in the Marine Environment. The authors describe distinctive characteristics of seabird life-histories in comparison to other taxa, hypotheses for why those lifestyles evolved and the potential role of energy limitation in the evolution of seabird life-histories. Along with a discussion of other common seabird traits, such as a propensity for colonial breeding, the authors also suggest directions for future research in seabird ecology.