Papers by Jonathan Hoekstra
Climate change is already impacting the 50% of humanity that lives along coasts Population densit... more Climate change is already impacting the 50% of humanity that lives along coasts Population densities in coastal regions are about three times higher than the global average, with 23 per cent of the world's population living both within 100 kilometer distance of the coast and less than 100 meters above sea level. Sixty percent of the world's cities with a population of over 5 million are located within 100 kilometers of the coast. Many of the world's poorest communities also live along the coast and rely on mangrove and reef-based fisheries for food security and on tourism for foreign exchange, particularly in small islands and tropical developing countries. This, coupled with poor adaptive capacity of the local populations and the governments, makes these areas highly vulnerable.
The NCEAS HCP working group consisted of 106 students participating in a nationwide graduate-leve... more The NCEAS HCP working group consisted of 106 students participating in a nationwide graduate-level course led by the following faculty advisors: Opinions expressed by the authors of this publication are their own and do not necessarily reflect the opinions of the American Institute of Biological Sciences, the National Center for Ecological Analysis and Synthesis, nor the institutions with which the authors are affiliated. The Endangered Species Act of 1973 (ESA) was established to save species at risk of extinction and to protect the ecosystems upon which they depend. Toward that aim, the ESA makes it unlawful for any person to "take" a listed species. In 1982, the ESA was amended to authorize incidental taking of endangered species by private landowners and other non-federal entities, provided they develop habitat conservation plans (HCPs) that minimize and mitigate the taking. Since 1982, HCPs have rapidly proliferated, leading in turn to widespread concern among conserv...
Ecological Applications, 2002
Revisions allow the recovery planning process for threatened and endangered species to be flexibl... more Revisions allow the recovery planning process for threatened and endangered species to be flexible and responsive to new information or changes in the status of a species. However, the Endangered Species Act defines neither firm criteria that trigger revision of recovery plans ...
Conservation Biology, 2003
The American Naturalist, 2001
Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears... more Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission.
Proceedings of The National Academy of Sciences, 2001
Directional selection is a major force driving adaptation and evo- lutionary change. However, the... more Directional selection is a major force driving adaptation and evo- lutionary change. However, the distribution, strength, and tempo of phenotypic selection acting on quantitative traits in natural populations remain unclear across different study systems. We reviewed the literature (1984 -1997) that reported the strength of directional selection as indexed by standardized linear selection gradients (b). We asked how strong are
PLoS ONE, 2008
Background. Conventional wisdom identifies biodiversity hotspots as priorities for conservation i... more Background. Conventional wisdom identifies biodiversity hotspots as priorities for conservation investment because they capture dense concentrations of species. However, density of species does not necessarily imply conservation 'efficiency'. Here we explicitly consider conservation efficiency in terms of species protected per dollar invested. Methodology/Principal Findings. We apply a dynamic return on investment approach to a global biome and compare it with three alternate priority setting approaches and a random allocation of funding. After twenty years of acquiring habitat, the return on investment approach protects between 32% and 69% more species compared to the other priority setting approaches. To correct for potential inefficiencies of protecting the same species multiple times we account for the complementarity of species, protecting up to three times more distinct vertebrate species than alternate approaches. Conclusions/Significance. Incorporating costs in a return on investment framework expands priorities to include areas not traditionally highlighted as priorities based on conventional irreplaceability and vulnerability approaches.
PLoS Biology, 2007
Conservation priority-setting schemes have not yet combined geographic priorities with a framewor... more Conservation priority-setting schemes have not yet combined geographic priorities with a framework that can guide the allocation of funds among alternate conservation actions that address specific threats. We develop such a framework, and apply it to 17 of the world's 39 Mediterranean ecoregions. This framework offers an improvement over approaches that only focus on land purchase or species richness and do not account for threats. We discover that one could protect many more plant and vertebrate species by investing in a sequence of conservation actions targeted towards specific threats, such as invasive species control, land acquisition, and off-reserve management, than by relying solely on acquiring land for protected areas. Applying this new framework will ensure investment in actions that provide the most cost-effective outcomes for biodiversity conservation. This will help to minimise the misallocation of scarce conservation resources.
Journal of Biogeography, 2008
Aim Twelve per cent of the Earth's terrestrial surface is covered by protected areas, but neither... more Aim Twelve per cent of the Earth's terrestrial surface is covered by protected areas, but neither these areas nor the biodiversity they contain are evenly distributed spatially. To guide future establishment of protected areas, it is important to understand the factors that have shaped the spatial arrangement of the current protected area system. We used an information-theoretic approach to assess the ability of vertebrate biodiversity measures, resource consumption and agricultural potential to explain the global coverage pattern of protected areas.
Evolution, 2001
The mechanism of sex determination in mammals appears highly conserved: the presence of a Y chrom... more The mechanism of sex determination in mammals appears highly conserved: the presence of a Y chromosome triggers the male developmental pathway, whereas the absence of a Y chromosome results in a default female phenotype. However, if the Y chromosome fails to initiate the male pathway (referred to as Y*), XY* females can result, as is the case in several species of South American field mice (genus Akodon). The breeding genetics in this system inherently select against the Y* chromosome such that the frequency of XY* females should decrease rapidly to very low frequencies. However, in natural populations of Akodon, XY* females persist at substantial frequencies; for example, 10% of females are XY* in A. azarae and 30% in A. boliviensis. We develop a mathematical model that considers the potential roles of three evolutionary forces in maintaining XY* females: Y-to-Y* chromosome transitions (mutation), chromosome segregation distortion (meiotic drive), and differential fecundity (selection). We then test the predictions of our model using data from breeding colonies of A. azarae. We conclude that any single force is inadequate to maintain XY* females. However, a combination of segregation bias of the male and female Y chromosomes during spermatogenesis/oogenesis and increased fecundity in XY* females could account for the observed frequencies of XY* females.
Ecology Letters, 2004
Human impacts on the natural environment have reached such proportions that in addition to an Ôex... more Human impacts on the natural environment have reached such proportions that in addition to an Ôextinction crisisÕ, we now also face a broader Ôbiome crisisÕ. Here we identify the world's terrestrial biomes and, at a finer spatial scale, ecoregions in which biodiversity and ecological function are at greatest risk because of extensive habitat conversion and limited habitat protection. Habitat conversion exceeds habitat protection by a ratio of 8 : 1 in temperate grasslands and Mediterranean biomes, and 10 : 1 in more than 140 ecoregions. These regions include some of the most biologically distinctive, species rich ecosystems on Earth, as well as the last home of many threatened and endangered species. Confronting the biome crisis requires a concerted and comprehensive response aimed at protecting not only species, but the variety of landscapes, ecological interactions, and evolutionary pressures that sustain biodiversity, generate ecosystem services, and evolve new species in the future.
Ecological Applications, 2002
Revisions allow the recovery planning process for threatened and endangered species to be flexibl... more Revisions allow the recovery planning process for threatened and endangered species to be flexible and responsive to new information or changes in the status of a species. However, the Endangered Species Act defines neither firm criteria that trigger revision of recovery plans ...
Ecological Applications, 2002
... J, K, AA, BB, KK, LL, WW, XX, CCC, DDD, ZZZ, ABC). Responses to these questions were based on... more ... J, K, AA, BB, KK, LL, WW, XX, CCC, DDD, ZZZ, ABC). Responses to these questions were based on data provided to us by the USFWS. ... J, K, AA, BB, KK, LL, WW, XX, CCC,DDD, ZZZ, ABC) and estimated costs of implementation (cols. ...
Ecological Applications, 2002
The US Endangered Species Act (ESA) generally requires that critical habitat be designated for al... more The US Endangered Species Act (ESA) generally requires that critical habitat be designated for all species listed as endangered or threatened. However, it has been designated for only~ 10% of listed species. Recently, in response to several recent court orders and ...
Ecological Applications, 2007
Chinook salmon (Oncorhynchus tshawytscha) have declined dramatically across the Pacific Northwest... more Chinook salmon (Oncorhynchus tshawytscha) have declined dramatically across the Pacific Northwest because of multiple human impacts colloquially characterized as the four "H's": habitat degradation, harvest, hydroelectric and other dams, and hatchery production. We use this conceptual framework to quantify the relative importance of major threats to the current status of 201 Chinook populations. Current status is characterized by two demographic indices: population density and trend. We employ path analytic models and information theoretic methods for multi-model inference. Our results indicate that dams most strongly affect variation in population density, while harvest and hatchery production most strongly affect variation in population trend. Comparable results arise when the sample size of the analysis is reduced to 22 Chinook populations within a smaller region typical of the scale at which salmon recovery planning is conducted. Results from these threat analyses suggest that recovery strategies targeting specific demographic indices, and those considering natural and human-mediated interdependencies of major threats, are most likely to succeed.
Conservation Letters, 2011
Efforts to set global conservation priorities have largely ignored freshwater diversity, thereby ... more Efforts to set global conservation priorities have largely ignored freshwater diversity, thereby excluding some of the world's most speciose, threatened, and valuable taxa. Using a new global map of freshwater ecoregions and distribution data for about 13,300 fish species, we identify regions of exceptional freshwater biodiversity and assess their overlap with regions of equivalent terrestrial importance. Overlap is greatest in the tropics and is higher than expected by chance. These high-congruence areas offer opportunities for integrated conservation efforts, which could be of particular value when economic conditions force conservation organizations to narrow their focus. Areas of low overlap-missed by current terrestrially based priority schemes-merit independent freshwater conservation efforts. These results provide new information to conservation investors setting priorities at global or regional scales and argue for a potential reallocation of future resources to achieve representation of overlooked biomes.
Conservation Biology, 2003
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Papers by Jonathan Hoekstra