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1.
Aim We evaluated Odonata distribution data and predicted the compositional resemblance based on niche‐based species distribution models to analyse the following questions: (1) How is estimated species richness distributed, and how can it be preserved under the actual network of conservation units (a gap analysis approach)? (2) How is the estimated odonate beta diversity distributed, and is there a better distribution of conservation units (a priority setting approach)? (3) Is the probability of being under protection a function of the potential species range size? and (4) Will the current conservation network proposals protect odonate taxa? Location Central Brazil in a core Cerrado area. Methods We generated odonate species distribution predictions based on MaxEnt and maps derived from estimated species richness, beta diversity and gap analysis for all species predicted to occur in the study area. Then, we compared these maps with current conservation units, land‐use patterns and proposals for the establishment of conservation units. Results Raw odonate species records provided limited utility for setting conservation priorities without the use of niche‐based models. However, area under the receiver operating curve (AUC) values were characterized by substantial variation that was related to the number of records. No current conservation units overlapped the areas with higher predicted richness and beta diversity, and in general, conservation units were not preserving restricted/rare species. There was a direct linear correlation between species range size and the proportion of its range protected in the current network of conservation units. Finally, we identified three areas with high odonate beta diversity where conservationist actions should be implemented. Main conclusions Current conservation units and future suggested areas do not overlap regions with high conservation values for odonates. Conservation units protect species at random, and the level of protection has a direct relationship with species range size; thus, wide‐range species are expected to be more protected than restricted or threatened species. 相似文献
2.
Effects of errors in range maps on estimates of historical species richness of mammals in Canadian national parks 总被引:1,自引:1,他引:0
Aim Tests for faunal relaxation in reserves, particularly for mammals, have relied on comparisons of current species richness with estimates of species richness derived from historical range maps. However, any range map reflects the extent of occurrence of species and not necessarily the area of occupancy. Thus, estimates of historical species richness might be prone to error introduced by ‘false positives’, that is, a species might be considered to have been present in locations where it actually was not. The effect of such ‘false positives’ could bias statistical tests of faunal relaxation to type I error, and result in estimates of the extent of faunal relaxation in reserves greater than was actually the case. We evaluated the potential for errors in historical range maps to generate inflated estimates of historical species richness of mammals at sites that are reserves today. Location Canadian national parks in the Canadian portion of the Alleghenian‐‐Illinoian mammal province in south‐eastern Canada (the maritime region and parts of southern Québec, Ontario and Manitoba). Methods The effect of varying levels of error in range maps on estimates of historical species richness was tested using geographical information systems (GIS)‐based statistical sampling of simulated historical ranges. Species’ areas of occupancy were simulated to be only 25%, 75% and 95% of published historical species ranges. For each reserve, estimates of historical species richness from these simulated species ranges were then compared with similar, previously published estimates of richness based on published historical species ranges. Results Previous estimates of historical species richness for reserves were inversely and linearly related to the degree of inaccuracy of species ranges. If species ranges were, on average, 5% smaller than the accepted ranges, then estimates of historical species richness agreed with previous estimates in c. 90% of cases. However, if historical ranges were, on average, 25% smaller than those used in previous analyses, then previous historical estimates of species richness may be overestimates in c. 40% of cases. Main conclusions Estimates of the extent of faunal relaxation in reserves that use historical range maps to quantify past species richness appear to be sensitive to even small errors in the degree to which range maps may overestimate ‘area of occupancy’. 相似文献
3.
Patterns of species richness hotspots and estimates of their protection are sensitive to spatial resolution
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Alexa J. McKerrow Nathan M. Tarr Matthew J. Rubino Steven G. Williams 《Diversity & distributions》2018,24(10):1464-1477
Aim
Species richness is a measure of biodiversity often used in spatial conservation assessments and mapped by summing species distribution maps. Commission errors inherent those maps influence richness patterns and conservation assessments. We sought to further the understanding of the sensitivity of hotspot delineation methods and conservation assessments to commission errors, and choice of threshold for hotspot delineation.Location
United States.Methods
We created range maps and 30‐m and 1‐km resolution habitat maps for terrestrial vertebrates in the United States and generated species richness maps with each dataset. With the richness maps and the GAP Protected Areas Dataset, we created species richness hotspot maps and calculated the proportion of hotspots within protected areas; calculating protection under a range of thresholds for defining hotspots. Our method allowed us to identify the influence of commission errors by comparing hotspot maps.Results
Commission errors from coarse spatial grain data and lack of porosity in the range data inflated richness estimates and altered their spatial patterns. Coincidence of hotspots from different data types was low. The 30‐m hotspots were spatially dispersed, and some were very long distances from the hotspots mapped with coarser data. Estimates of protection were low for each of the taxa. The relationship between estimates of hotspot protection and threshold choice was nonlinear and inconsistent among data types (habitat and range) and grain size (30‐m and 1‐km).Main conclusions
Coarse mapping methods and grain sizes can introduce commission errors into species distribution data that could result in misidentifications of the regions where hotspots occur and affect estimates of hotspot protection. Hotspot conservation assessments are also sensitive to choice of threshold for hotspot delineation. There is value in developing species distribution maps with high resolution and low rates of commission error for conservation assessments. 相似文献4.
Aim The method used to generate hypotheses about species distributions, in addition to spatial scale, may affect the biodiversity patterns that are then observed. We compared the performance of range maps and MaxEnt species distribution models at different spatial resolutions by examining the degree of similarity between predicted species richness and composition against observed values from well‐surveyed cells (WSCs). Location Mexico. Methods We estimated amphibian richness distributions at five spatial resolutions (from 0.083° to 2°) by overlaying 370 individual range maps or MaxEnt predictions, comparing the similarity of the spatial patterns and correlating predicted values with the observed values for WSCs. Additionally, we looked at species composition and assessed commission and omission errors associated with each method. Results MaxEnt predictions reveal greater geographic differences in richness between species rich and species poor regions than the range maps did at the five resolutions assessed. Correlations between species richness values estimated by either of the two procedures and the observed values from the WSCs increased with decreasing resolution. The slopes of the regressions between the predicted and observed values indicate that MaxEnt overpredicts observed species richness at all of the resolutions used, while range maps underpredict them, except at the finest resolution. Prediction errors did not vary significantly between methods at any resolution and tended to decrease with decreasing resolution. The accuracy of both procedures was clearly different when commission and omission errors were examined separately. Main conclusions Despite the congruent increase in the geographic richness patterns obtained from both procedures as resolution decreases, the maps created with these methods cannot be used interchangeably because of notable differences in the species compositions they report. 相似文献
5.
Marine reserves that prohibit fishing often result in greater densities of individuals and more species than adjacent fished areas. However, simple conclusions about their effects on species richness are confounded, because more species are expected to occur wherever there are more individuals. Here, there is an important distinction between the number of species per sampling unit (species density), and species richness measured as the number of species per given number of individuals. When conservation of species richness is an important goal, analyses need to discriminate between the alternative explanations for differences in the number of species. We used rarefaction to test whether species richness was higher in two ‘no-take’ marine reserves after controlling for differences in the density of individuals. We surveyed each reserve in three different years. There was a higher density of individuals and species in each reserve than in adjacent fished areas. However, rarefaction analyses indicated that effects on species richness were weak after controlling for the number of individuals: slightly higher species richness was recorded inside each reserve in one of three surveys, but the difference was small, and was apparent only when the maximum number of individuals was approached. Our results therefore indicate that patterns in species density were not reflected by patterns in species richness—the application of rarefaction methods is needed to determine the responses of species richness to protection elsewhere. The distinction between species density and species richness will not be important in all situations, but when it is important, inferences about species richness cannot be reliably deduced from measurements of species density. 相似文献
6.
Misuse of bird digital distribution maps creates reversed spatial diversity patterns in the Amazon
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Mariana M. Vale Tamires L. Marques Mario Cohn‐Haft Marcus Vinícius Vieira 《Biotropica》2017,49(5):636-642
It is well known that bird richness in the Amazon is greater in upland forests and that seasonally flooded forest is particularly species poor. However, the misleading pattern of greater bird richness in seasonally flooded forest has emerged seemingly unnoticed numerous times in richness maps in the literature. We hypothesize that commission errors in digital distribution maps (DDMs) are the cause behind the misleading richness pattern. In the Amazon, commission errors are a consequence of the different methodological treatment given to large‐ranged versus small‐ranged habitat specialists when mapping distributions. DDMs of 1007 Amazonian birds were examined, and maps that had commission errors were corrected. We generated two richness maps, one from the overlay of original DDMs and another from the overlay of the corrected ones. We identified 291 species whose distribution maps had errors. In the original data, seasonally flooded forests showed higher species richness than upland forest, but this pattern was reverted in the corrected richness map. Commission errors were 35 times more likely in the seasonally flooded forest. We conclude that DDMs accurately portray the distribution of single species in the Amazon. Commission errors in individual maps, however, accumulate when they are overlaid, explaining the misleading pattern for birds in the Amazon. DDMs can continue to be used mapping richness, as long as, at a regional scale: (1) basic map refinements are carried, or (2) only small‐range species are used for mapping species richness. 相似文献
7.
Although species distribution modelling (SDM) is widely accepted among the scientific community and is increasingly used in ecology, conservation biology and biogeography, methodological limitations generate potential problems for its application in macroecology. Using amphibian species richness in North and South America, we compare species richness patterns derived from SDM maps and ‘expert’ maps to evaluate if: 1) richness patterns derived from SDM are biased toward climate‐based explanations for diversity when compared to expert maps, since SDM methods are typically based on climatic variables; and 2) SDM is a reliable tool for generating richness maps in hyperrich regions where point occurrence data are limited for many species. We found that although three widely used SDM methods overestimated amphibian species richness in grid cells when compared to expert richness maps in both North and South America due to systematic overestimation of range sizes, diversity gradients were reasonably robust at broad scales. Further, climatic variables statistically explained patterns of richness at similar levels among the different richness sources, although climatic relationships were stronger in the much better known North America than in South America. We conclude that in the face of the high deforestation rates coupled with incomplete data on species distributions, especially in the tropics, SDM represents a useful macroecological tool for investigating broad‐scale richness patterns and the dynamics between species richness and climate. 相似文献
8.
Regimes of chlorophyll‐a in the Coral Sea: implications for evaluating adequacy of marine protected areas
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Heather Welch Robert L. Pressey Scott F. Heron Daniela M. Ceccarelli Alistair J. Hobday 《Ecography》2016,39(3):289-304
Spatial management of the highly dynamic pelagic realm, and the highly mobile species it supports, requires dynamic processes to be incorporated into reserve design. To achieve this, planners need information on how these processes vary across space and time, and how this variation relates to species of conservation interest. This study presents a new method of quantifying variability that captures both between‐ and within‐year changes in variables of interest. We applied this method to remotely‐sensed chlorophyll‐a in the Coral Sea to find five distinct regimes of variation that serve as surrogates for assemblages of species of conservation interest. We performed a gap analysis to determine protection of the regimes both internationally and nationally within Australia's network of marine reserves in the Coral Sea. We also identified key areas for protection within each regime, in terms of chlorophyll‐a variability and species associations, and examined their protection status. Depending on conservation objectives, reserve systems that span multiple national jurisdictions and a rezoning of Australian national waters might be necessary to meet protection requirements for the regimes and for key areas within them. The current suspension and review of the Coral Sea Commonwealth Marine Reserve management plans and the recent proclamation of New Caledonia's as yet unzoned Coral Sea Nature Park offer planners an opportunity to incorporate dynamic processes into conservation planning for the Coral Sea. The method we present can be applied at other locations for time‐series of any variable/s of interest, aiding the spatial management of dynamic features in both marine and terrestrial contexts. 相似文献
9.
In order to better understand the relationship between reserve design and the species represented by such designs, we examined
the effectiveness of the Western Australian reserve system for conserving angiosperm diversity, and examined the characteristics
of those species conserved. We overlayed species distribution data for 14 plant lineages with the distribution of the reserve
system (8.5% of the State’s area) and identified the species that remained unprotected. We found that, depending upon the
method employed, between 174 (5.7%) and 570 (18.7%) of species were not included within the reserve system. Two main unprotected
regions were identified, one of which was also a centre of high diversity. Geographical range sizes of unprotected species
were six times smaller than those species that were protected, while species richness of small-ranged endemic species coincided
with general patterns of species richness. At the level of Western Australia’s bioregions we found that conservation effectiveness
was most dependent on characteristics of the reserve system rather than characteristics (size and positioning) of species
ranges. At this scale, the most effective way to conserve more species in Western Australia would be to conserve more land,
while conservation would be most successful in a uniformly dispersed reserve system. Our results highlight the fact that reserve
systems may take on two design approaches based on scale––at continental scales, reserves should be clustered around the hotspots
of endemic species, while within regions, an evenly distributed reserve system will most adequately sample species. 相似文献
10.
The value of coarse species range maps to inform local biodiversity conservation in a global context
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Range maps of thousands of species, compiled and made freely available by the International Union for Conservation of Nature, are being increasingly applied to support spatial conservation planning. However, their coarse nature makes them prone to commission and omission errors, and they lack information on the variations in abundance within species’ distributions, calling into question their value to inform decisions at the fine scales at which conservation often takes place. Here, we tested if species ranges can reliably be used to estimate the responsibility of sites for the global conservation of species. We defined ‘specific responsibility’ as the fraction of a species’ population within a given site, considering it useful for prioritising species within sites; and defined ‘overall responsibility’ as the sum of specific responsibility across species within a site, assuming it informative of priorities among sites. Taking advantage of an exceptionally detailed dataset on the distribution and abundance of bird species at a near‐continental scale – a level of information rarely available to local decision‐makers – we created a benchmark against which we tested estimates of responsibility derived from range maps. We investigated approaches for improving these estimates by complementing range maps with plausibly available local data. We found that despite their coarse nature, range maps provided good estimates of sites’ overall responsibility, but relatively poor estimates of specific responsibility. Estimates were improved by combining range maps with local species lists or local abundance data, easily available through local surveys on the sites of interest, or simulated expert knowledge. Our results suggest that combining range maps with local data is a promising route for improving the effectiveness of local conservation decisions at contributing to reducing global biodiversity losses. This is all the more urgent in hyper‐diverse poorly‐known regions where conservation‐relevant decisions must proceed despite a paucity of biodiversity data. 相似文献
11.
Understanding the forces that shape the distribution of biodiversity across spatial scales is central in ecology and critical to effective conservation. To assess effects of possible richness drivers, we sampled ant communities on four elevational transects across two mountain ranges in Colorado, USA, with seven or eight sites on each transect and twenty repeatedly sampled pitfall trap pairs at each site each for a total of 90 d. With a multi‐scale hierarchical Bayesian community occupancy model, we simultaneously evaluated the effects of temperature, productivity, area, habitat diversity, vegetation structure, and temperature variability on ant richness at two spatial scales, quantifying detection error and genus‐level phylogenetic effects. We fit the model with data from one mountain range and tested predictive ability with data from the other mountain range. In total, we detected 105 ant species, and richness peaked at intermediate elevations on each transect. Species‐specific thermal preferences drove richness at each elevation with marginal effects of site‐scale productivity. Trap‐scale richness was primarily influenced by elevation‐scale variables along with a negative impact of canopy cover. Soil diversity had a marginal negative effect while daily temperature variation had a marginal positive effect. We detected no impact of area, land cover diversity, trap‐scale productivity, or tree density. While phylogenetic relationships among genera had little influence, congeners tended to respond similarly. The hierarchical model, trained on data from the first mountain range, predicted the trends on the second mountain range better than multiple regression, reducing root mean squared error up to 65%. Compared to a more standard approach, this modeling framework better predicts patterns on a novel mountain range and provides a nuanced, detailed evaluation of ant communities at two spatial scales. 相似文献
12.
In the past years, efforts have been made to include connectivity metrics in conservation planning in order to promote and enhance well-connected systems of protected areas. Connectivity is particularly important for species that rely on more than one realm during their daily or life cycle (multi-realm species). However, conservation plans for the protection of multi-realm species usually involve a single realm, excluding other realms from the prioritization process. Here, we demonstrate an example of cross-realm conservation planning application for the island of Cyprus by taking into account the terrestrial and marine realms and their interface (i.e. coast). Operating within a data-poor context, we use functional connectivity metrics to identify priority areas for the conservation of six multi-realm species, by setting conservation targets simultaneously for the terrestrial and marine realms. MARXAN decision-support tool was used for the identification of the priority areas.Four scenarios were developed to evaluate the impacts of including connectivity in the prioritization process and the effectiveness of the existing coastal/marine protected areas in the achievement of the conservation targets set for the species. All scenarios considered land and sea anthropogenic uses as surrogate costs to influence the prioritization process.Our findings show an increase in the area of the reserve network and, therefore, the cost, when connectivity is included, whilst reducing the total boundary length. Furthermore, the current reserve network fails to achieve conservation targets, particularly for the marine part, which has a substantially smaller protection coverage than the terrestrial part.We conclude that focus should be given in the expansion of the current coastal/marine reserve network following a cross-realm conservation approach. This approach is not only relevant for the conservation of multi-realm species, but also for islandscapes, in particular, where the interdependence between the hinterland and the coast is larger and therefore the magnitude of the impacts generated in one realm and affects the other. 相似文献
13.
How well do Important Bird Areas represent species and minimize conservation conflict in the tropical Andes? 总被引:3,自引:1,他引:2
Where high species richness and high human population density coincide, potential exists for conflict between the imperatives of species conservation and human development. We examine the coincidence of at‐risk bird species richness and human population in the countries of the tropical Andes. We then compare the performance of the expert‐driven Important Bird Areas (IBA) scheme against a hypothetical protected‐areas network identified with a systematic reserve selection algorithm seeking to maximize at‐risk bird species representation. Our aim is to assess the degree to which: IBAs contain a higher richness of at‐risk species than would be expected by chance, IBAs contain more people than would be expected by chance, and IBAs are congruent with complementary areas that maximize species representation with an equivalent number of sites. While the correlation of richness and population was low for the region as a whole, representation of all at‐risk bird species required many sites to be located in areas of high human population density. IBA sites contained higher human population densities than expected by chance (P < 0.05) and were markedly less efficient in representing at‐risk bird species of the region than sites selected using the reserve selection algorithm. Moreover, overlap between IBAs and these latter sites was very limited. Expert‐driven selection procedures may better reflect existing sociopolitical forces, including land ownership and management regimes, but are limited in their ability to develop an efficient, integrated network of sites to represent priority species. Reserve selection algorithms may serve this end by optimizing complementarity in species representation among selected sites, whether these sites are adopted independently or as a supplement to the existing reserve network. As tools of site selection, they may be particularly useful in areas such as the tropical Andes where complex patterns of species disjunction and co‐occurrence make the development of representative reserve networks particularly difficult. Furthermore, they facilitate making spatially explicit choices about how reserve sites are located in relation to human populations. We advocate their use not in replacement of approaches such as the IBA initiative but as an additional, complementary tool in ensuring that such reserve networks are developed as efficiently as practically possible. 相似文献
14.
Does conservation planning matter in a dynamic and uncertain world? 总被引:10,自引:0,他引:10
Loss of biodiversity is one of the world's overriding environmental challenges. Reducing those losses by creating reserve networks is a cornerstone of global conservation and resource management. Historically, assembly of reserve networks has been ad hoc, but recently the focus has shifted to identifying optimal reserve networks. We show that while comprehensive reserve network design is best when the entire network can be implemented immediately, when conservation investments must be staged over years, such solutions actually may be sub‐optimal in the context of biodiversity loss and uncertainty. Simple decision rules, such as protecting the available site with the highest irreplaceability or with the highest species richness, may be more effective when implementation occurs over many years. 相似文献
15.
Claudet J Osenberg CW Benedetti-Cecchi L Domenici P García-Charton JA Pérez-Ruzafa A Badalamenti F Bayle-Sempere J Brito A Bulleri F Culioli JM Dimech M Falcón JM Guala I Milazzo M Sánchez-Meca J Somerfield PJ Stobart B Vandeperre F Valle C Planes S 《Ecology letters》2008,11(5):481-489
Marine reserves are widely used throughout the world to prevent overfishing and conserve biodiversity, but uncertainties remain about their optimal design. The effects of marine reserves are heterogeneous. Despite theoretical findings, empirical studies have previously found no effect of size on the effectiveness of marine reserves in protecting commercial fish stocks. Using 58 datasets from 19 European marine reserves, we show that reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect. Moreover, positive effects of marine reserve on commercial fish species and species richness are linked to the time elapsed since the establishment of the protection scheme. The reserve size-dependency of the response to protection has strong implications for the spatial management of coastal areas because marine reserves are used for spatial zoning. 相似文献
16.
A. Chiarucci G. Bacaro G. Filibeck S. Landi S. Maccherini A. Scoppola 《Biodiversity and Conservation》2012,21(2):503-516
Despite the widely recognised importance of reserve networks, their effectiveness in encompassing and maintaining biodiversity
is still debated. Species diversity is one of the most affordable measures of biodiversity, but it is difficult to survey
such data over large scales. This research aimed to perform a sample-based assessment of species richness of groups of plants
with different conservation value (alien species, protected species, and all species) within a reserve network, testing the
use of partitioning as a tool for assessing diversity at different spatial scales, from the plot to the entire network. Plant
diversity patterns differed for the groups of species for most of the investigated spatial scales. Despite these patterns
assumed divergent tendencies when different species groups were considered, most of the species richness within the network
was given by larger scale β-diversity for both alien and protected species, as well for all species. Diversity partitioning
proved an effective tool to quantify the role of spatial scales in structuring the total species richness of the network,
and is helpful in planning reserve networks. 相似文献
17.
Protection from fishing generally results in an increase in the abundance and biomass of species targeted by fisheries within
marine reserve boundaries. Natural refuges such as depth may also protect such species, yet few studies in the Indo Pacific
have investigated the effects of depth concomitant with marine reserves. We studied the effects of artisanal fishing and depth
on reef fish assemblages in the Kubulau District of Vanua Levu Island, Fiji, using baited remote underwater stereo-video systems.
Video samples were collected from shallow (5–8 m) and deep (25–30 m) sites inside and outside of a large old marine reserve
(60.6 km2, 13 years old) and a small new marine reserve (4.25 km2, 4 years old). Species richness tended to be greater in the shallow waters of the large old reserve when compared to fished
areas. In the deeper waters, species richness appeared to be comparable. The difference in shallow waters was driven by species
targeted by fisheries, indicative of a depth refuge effect. In contrast, differences in the abundance composition of the fish
assemblage existed between protected and fished areas for deep sites, but not shallow. Fish species targeted by local fisheries
were 89% more abundant inside the large old reserve than surrounding fished areas, while non-targeted species were comparable.
We observed no difference in the species richness or abundance of species targeted by fisheries inside and outside of the
small new reserve. This study suggests that artisanal fishing impacts on the abundance and species richness of coral reef
fish assemblages and effects of protection are more apparent with large reserves that have been established for a long period
of time. Observed effects of protection also vary with depth, highlighting the importance of explicitly incorporating multiple
depth strata in studies of marine reserves. 相似文献
18.
Brendan P. Kelaher Melinda A. Coleman Allison Broad Matthew J. Rees Alan Jordan Andrew R. Davis 《PloS one》2014,9(1)
Networks of no-take marine reserves and partially-protected areas (with limited fishing) are being increasingly promoted as a means of conserving biodiversity. We examined changes in fish assemblages across a network of marine reserves and two different types of partially-protected areas within a marine park over the first 5 years of its establishment. We used Baited Remote Underwater Video (BRUV) to quantify fish communities on rocky reefs at 20–40 m depth between 2008–2011. Each year, we sampled 12 sites in 6 no-take marine reserves and 12 sites in two types of partially-protected areas with contrasting levels of protection (n = 4 BRUV stations per site). Fish abundances were 38% greater across the network of marine reserves compared to the partially-protected areas, although not all individual reserves performed equally. Compliance actions were positively associated with marine reserve responses, while reserve size had no apparent relationship with reserve performance after 5 years. The richness and abundance of fishes did not consistently differ between the two types of partially-protected areas. There was, therefore, no evidence that the more regulated partially-protected areas had additional conservation benefits for reef fish assemblages. Overall, our results demonstrate conservation benefits to fish assemblages from a newly established network of temperate marine reserves. They also show that ecological monitoring can contribute to adaptive management of newly established marine reserve networks, but the extent of this contribution is limited by the rate of change in marine communities in response to protection. 相似文献
19.
A. Márcia Barbosa Alba Estrada Ana L. Márquez Andy Purvis C. David L. Orme 《Journal of Biogeography》2012,39(8):1391-1400
Aim Chorological relationships describe the patterns of distributional overlap among species. In addition to revealing biogeographical structure, the resulting clusters of species with similar geographical distributions can serve as natural units in conservation planning. Here, we assess the extent to which temporal, methodological and taxonomical differences in the source of species’ distribution data can affect the relationships that are found. Location Western Europe. Methods We used two data sets – the Atlas of European mammals and polygon range maps from the IUCN Global Mammal Assessment – both as presence–absence data for UTM 50 km × 50 km squares. We performed pairwise comparisons among 156 species for each data set to build matrices of the similarity in distribution across species, using both Jaccard’s and Baroni‐Urbani & Buser’s indices. We then compared these similarity matrices (chorological relationships), as well as the species richness and occurrence patterns from the two data sets. Results As expected, range maps increased both the mean prevalence per species and mean species richness per grid cell in comparison to atlas data, reflecting the general view that these data types respectively over‐ and underestimate species occurrence. However, species richness and occurrence patterns in atlas and range map data were positively associated and, most importantly, the chorological relationships underlying the two data sets were highly similar. Main conclusions Despite many methodological, temporal and taxonomical differences between atlas data and range maps, the chorological relationships encountered between species were similar for both data sets. Chorological analyses can thus be robust to the data source used and provide a solid basis for analytical biogeographical studies, even over broad spatial scales. 相似文献
20.
Larval dispersal and movement patterns of coral reef fishes,and implications for marine reserve network design
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Alison L. Green Aileen P. Maypa Glenn R. Almany Kevin L. Rhodes Rebecca Weeks Rene A. Abesamis Mary G. Gleason Peter J. Mumby Alan T. White 《Biological reviews of the Cambridge Philosophical Society》2015,90(4):1215-1247
Well‐designed and effectively managed networks of marine reserves can be effective tools for both fisheries management and biodiversity conservation. Connectivity, the demographic linking of local populations through the dispersal of individuals as larvae, juveniles or adults, is a key ecological factor to consider in marine reserve design, since it has important implications for the persistence of metapopulations and their recovery from disturbance. For marine reserves to protect biodiversity and enhance populations of species in fished areas, they must be able to sustain focal species (particularly fishery species) within their boundaries, and be spaced such that they can function as mutually replenishing networks whilst providing recruitment subsidies to fished areas. Thus the configuration (size, spacing and location) of individual reserves within a network should be informed by larval dispersal and movement patterns of the species for which protection is required. In the past, empirical data regarding larval dispersal and movement patterns of adults and juveniles of many tropical marine species have been unavailable or inaccessible to practitioners responsible for marine reserve design. Recent empirical studies using new technologies have also provided fresh insights into movement patterns of many species and redefined our understanding of connectivity among populations through larval dispersal. Our review of movement patterns of 34 families (210 species) of coral reef fishes demonstrates that movement patterns (home ranges, ontogenetic shifts and spawning migrations) vary among and within species, and are influenced by a range of factors (e.g. size, sex, behaviour, density, habitat characteristics, season, tide and time of day). Some species move <0.1–0.5 km (e.g. damselfishes, butterflyfishes and angelfishes), <0.5–3 km (e.g. most parrotfishes, goatfishes and surgeonfishes) or 3–10 km (e.g. large parrotfishes and wrasses), while others move tens to hundreds (e.g. some groupers, emperors, snappers and jacks) or thousands of kilometres (e.g. some sharks and tuna). Larval dispersal distances tend to be <5–15 km, and self‐recruitment is common. Synthesising this information allows us, for the first time, to provide species, specific advice on the size, spacing and location of marine reserves in tropical marine ecosystems to maximise benefits for conservation and fisheries management for a range of taxa. We recommend that: (i) marine reserves should be more than twice the size of the home range of focal species (in all directions), thus marine reserves of various sizes will be required depending on which species require protection, how far they move, and if other effective protection is in place outside reserves; (ii) reserve spacing should be <15 km, with smaller reserves spaced more closely; and (iii) marine reserves should include habitats that are critical to the life history of focal species (e.g. home ranges, nursery grounds, migration corridors and spawning aggregations), and be located to accommodate movement patterns among these. We also provide practical advice for practitioners on how to use this information to design, evaluate and monitor the effectiveness of marine reserve networks within broader ecological, socioeconomic and management contexts. 相似文献