ArticlePDF Available


No caption available
Content may be subject to copyright. SCIENCE VOL 317 6 JULY 2007
frozen embryos
in depth
edited by Etta Kavanagh
A World Without Mangroves?
Australia, it was unanimously agreed that we face the prospect of a
world deprived of the services offered by mangrove ecosystems, per-
haps within the next 100 years.
Mangrove forests once covered more than 200,000 km
of shel-
tered tropical and subtropical coastlines (1). They are disappearing
worldwide by 1 to 2% per year, a rate greater than or equal to declines
in adjacent coral reefs or tropical rainforests (2–5). Losses are occur-
ring in almost every country that has mangroves, and rates continue to
rise more rapidly in developing countries, where >90% of the world’s
mangroves are located. The veracity and detail of the UN Food and
Agriculture Organization data (2) on which these observations are
based may be arguable, but mangrove losses during the last quarter
century range consistently between 35 and 86%. As mangrove areas
are becoming smaller or fragmented, their long-term survival is at
great risk, and essential ecosystem services may be lost.
Where mangrove forests are cleared for aquaculture, urbanization,
or coastal landfill or deteriorate due to indirect effects of pollution and
upstream land use (3, 4), their species richness is expected to decline
precipitously, because the number of mangrove plant species is directly
correlated with forest size (6, 7). Examples from other ecosystems
have shown that species extinctions can be followed by loss in func-
tional diversity, particularly in species-poor systems like mangroves,
which have low redundancy per se (8). Therefore, any further decline
in mangrove area is likely to be followed by accelerated functional
losses. Mangroves are already critically endangered or approaching
extinction in 26 out of the 120 countries having mangroves (2, 9).
Deforestation of mangrove forests, which have extraordinarly high
rates of primary productivity (3), reduces their dual capacity to be both
an atmospheric CO
sink (10) and an essential source of oceanic car-
bon. The support that mangrove ecosystems provide for terrestrial as
well as marine food webs would be lost, adversely affecting, for exam-
ple, fisheries (11). The decline further imperils mangrove-dependent
fauna with their complex habitat linkages, as well as phys-
ical benefits like the buffering of seagrass beds and coral
reefs against the impacts of river-borne siltation, or protec-
tion of coastal communities from sea-level rise, storm
surges, and tsunamis (12, 13). Human communities living
in or near mangroves would lose access to sources of essen-
tial food, fibers, timber, chemicals, and medicines (14).
We are greatly concerned that the full implications of
mangrove loss for humankind are not fully appreciated.
Growing pressures of urban and industrial developments
along coastlines, combined with climate change and sea-
level rise, urge the need to conserve, protect, and restore
tidal wetlands (11, 13). Effective governance structures,
socioeconomic risk policies, and education strategies (15)
are needed now to enable societies around the world to
reverse the trend of mangrove loss and ensure that future
generations enjoy the ecosystem services provided by such
valuable natural ecosystems.
S. Y. LEE,
Centre for Marine Studies, University of Queensland, St Lucia, Qld 4072, Australia.
Australian Rivers Institute and School of Environment, PMB 50 GCMC, Griffith University,
Qld 9726, Australia.
School of Biological Sciences, Flinders University, GPO Box 2100,
Adelaide, SA 5001, Australia.
Harvard University, Harvard Forest, 324 North Main Street,
Petersham, MA 01366, USA.
Alfred-Wegener-Institut für Polar- und Meeresforschung,
Kurpromenade, D-27498 Helgoland, Germany.
Technical University Dresden, Institut für
Waldwachstum und Forstliche Informatik, Postfach 1117 01735 Tharandt, Germany.
Dipartimento di Biologia Animale e Genetica “Leo Pardi,” Università degli Studi di Firenze,
Via Romana, 17, I-50125 Firenze, Italy.
Center for Tropical Marine Ecology,
Fahrenheitstrasse 6, 28359 Bremen, Germany.
U.S. Department of Agriculture Forest
Service, 2126 NW 7th Lane, Gainesville, FL 32603, USA.
Faculty of Science (Gore Hill),
University of Technology, Sydney, Post Office Box 123, Broadway NSW 2007, Australia.
Laboratory of General Botany and Nature Management, Mangrove Management Group,
Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
LGPMC, EA 3325,
University of New Caledonia, Noumea, New Caledonia, and UR 103, Institut de Recherche
pour le Développement (IRD), Marseille, France.
Biocomplexity Research Focus, c/o
Laboratory of General Botany and Nature Management, Mangrove Management Group,
Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
Emerging from the embrace of a mangrove tree–lined channel in northern Brazil, these
pescadores, like coastal fishers worldwide, know that healthy mangroves mean good fishing
and a secure livelihood.
Published by AAAS
on July 12, 2007 www.sciencemag.orgDownloaded from
*To whom correspondence should be addressed. E-mail:
References and Notes
1. M. D. Spalding, F. Blasco, C. D. Field, World Mangrove
Atlas (International Society for Mangrove Ecosystems,
Okinawa, Japan, 1997).
2. FAO, “Status and trends in mangrove area extent world-
wide” (Forest Resources Division, FAO, Paris, 2003).
3. D. M. Alongi, Environ. Conserv. 29, 331 (2002).
4. I. Valiela, J. L. Bowen, J. K. York, Bioscience 51, 807
5. R. Stone, Science 316, 678 (2007).
6. N. C. Duke, M. C. Ball, J. C. Ellison, Glob. Ecol. Biogeogr.
Lett. 7, 27 (1998).
7. A. M. Ellison, Trees Struct. Funct. 16, 181 (2002).
8. O. L. Petchey, K. J. Gaston, Proc. R. Soc. London B 69,
1721 (2002).
9. Global Marine Species Assessment:
10. D. R. Cahoon et al., J. Ecol. 91, 1093 (2003).
11. E. B. Barbier, Econ. Policy 22, 177 (2007).
12. F. Dahdouh-Guebas et al., Curr. Biol. 15, 443 (2005).
13. E. McLeod, R. V. Salm, Managing Mangroves for
Resilience to Climate Change (IUCN, 2006).
14. K. C. Ewel, R. R. Twilley, J. E. Ong, Glob. Ecol. Biogeogr.
Lett. 7, 83 (1998).
15. Mangroves Future Project (IUCN),
16. The 2006 Australian mangrove meetings (MMM) at the
Gold Coast and Daintree were sponsored by the
University of Queensland, Griffith University, James Cook
University, Queensland Department of Primary Industries
and Fisheries, and the Ian Potter Foundation. We thank
our funding sources for their support of our research on
mangroves. F.D.G. is a Postdoctoral Research Scientist
from the Research Foundation - Flanders (FWO-
Vlaanderen). S.C.’s research is funded by the PUMPSEA
project (EU 6th FP). A.M.E.’s research is supported by the
Harvard Forest and by the U.S. NSF.
Supporting Undergraduate
“Benefits of undergraduate research experi-
ences” by S. H. Russell and colleagues (27
April, p. 548) confirm the widely held belief
that undergraduate research increases interest
in scientific and related research careers.
Indeed, as student researchers and editors with
an international undergraduate journal,
the Journal of Young Investigators (JYI;, we have experienced first-hand
several of the points that the authors raised.
We at JYI, however, believe that under-
graduate research programs should place
more emphasis on the art of scientific com-
munication. The benefits include the opportu-
nity to communicate undergraduate research
work to a broader audience. Such an experi-
ence also develops skills necessary for the
fluid but logical nature of scientific writing.
These skills are otherwise missed when
engrossed in wet lab work or not developed
fully when merely writing final lab reports. A
culture of responsibility and integrity is also
developed as student authors face rigorous
demands of scientific review and editing (data
integrity, plagiarism, etc.).
Most importantly, the undergraduate pub-
lication experience gives students an early
introduction to the world of peer review, a cor-
nerstone of science. For JYI, a student-led
journal, this benefit is doubly advantageous.
Not only do student authors benefit from peer
review, our JYI student reviewers are also
trained in the art of reviewing, a skill not given
much emphasis in undergraduate research.
JYI has been at the forefront of such under-
graduate peer review and publication for 10
years since its inception in 1997. From over
500 submissions, we have published 120
undergraduate research articles. Our high-
lights for the past year include 10 special issues
devoted to publishing research articles of vari-
ous universities’ Research Experiences for
Undergraduates program, and participation in
the recent 2007 AAAS Meeting, during which
we hosted a workshop for science writing.
Our aim is to see science writing and
communication play a central role in the
undergraduate research experience.
Department of Psychology, National University of
Singapore, Singapore.
Department of Neuroscience,
Canadian Center for Behavioural Neuroscience, Lethbridge,
AC T1K 3M4, Canada.
Optical Materials and Systems
Division, DSI Building, Data Storage Institute, 5
Engineering Drive 1, Singapore, 117608.
Department of
Medicine, Tribhuvan University, Kathmandu, POB No 1524,
Department of Microbiology, Immunology, and
Molecular Genetics, University of California at Los Angeles,
Los Angeles, CA 90095, USA.
Department of Biomedical
Engineering, Johns Hopkins University, Baltimore, MD
21218, USA.
Department of Human Biology, Stanford
University, Stanford, CA 94305, USA.
Isoprene, Cloud Droplets,
and Phytoplankton
the main conclusion of the Research Article
“Phytoplankton and cloudiness in the South-
ern Ocean” by N. Meskhidze and A. Nenes
(1 Dec. 2006, p. 1419). The authors report an
increase in cloud reflectivity resulting from a
30% decrease in cloud droplet effective radius
and a doubling of cloud droplet number con-
centration over a large phytoplankton bloom
in the Southern Ocean, resulting in an extra 15
W m
of energy reflected back to space. They
attribute these changes to enhanced isoprene
produced in the bloom. Our measurements
made during the Southern Ocean Iron Ex-
periments (SOFeX) (1) were used by Mesk-
hidze and Nenes to scale seawater isoprene
values based on measured chlorophyll-a con-
centrations. Unfortunately, they converted our
isoprene concentrations incorrectly, result-
ing in a three-order-of-magnitude overesti-
mation and hence a much greater calculated
isoprene flux.
During SOFeX, we measured climate-
relevant organic gases in the dynamic head-
space of an equilibrator (2) in contact with
seawater (1). We reported isoprene concen-
trations to be on average 560 pptv (parts per
trillion by volume or picomoles mole
air) inside of the SOFeX North Patch (NP),
which is the mixing ratio that the air above
the water would have if the headspace were
static. To convert from mixing ratio of static
headspace to seawater concentration, we use
Henry’s Law:
× K
= C
(Eq. 1)
where C
is the mixing ratio of a gas in equi-
librium with the dissolved gas in the aqueous
phase, C
. An average Henry’s law constant
) for isoprene of 0.0130 M atm
was used
(3). Therefore, the average seawater isoprene
concentration in the NP was ~7.3 picomoles
(pM). Listed in the authors’ Table 2 is an
average isoprene concentration of 31.4
nanomoles L
(nM) in the NP. This leads me
to believe that isoprene is not the reason for
their observed extra cloud albedo.
New Mexico Institute of Mining and Technology, Socorro,
NM 87801, USA.
1. O. W. Wingenter et al., Proc. Natl. Acad. Sci. U.S.A. 101,
8537 (2004) (doi:10.1073).
2. J. E. Johnson, Anal. Chim. Acta 395, 119 (1999).
3. R. Sander,
Indeed, we misinterpreted some of the data
in Wingenter et al. (1). We were unaware
that “concentration of dissolved gases
measured in and around the fertilized
patch” in (1) referred not to seawater con-
Letters to the Editor
Letters (~300 words) discuss material published
in Science in the previous 3 months or issues of
general interest. They can be submitted through
the Web ( or by regular
mail (1200 New York Ave., NW, Washington, DC
20005, USA). Letters are not acknowledged upon
receipt, nor are authors generally consulted before
publication. Whether published in full or in part,
letters are subject to editing for clarity and space.
Published by AAAS
on July 12, 2007 www.sciencemag.orgDownloaded from
... Some fish and shellfish breed, spawn and hatch exclusively in mangroves. Many local communities use wood and other parts of mangrove as material for construction, boats, firewood, craft, snack, and food [8,9]. Moreover, mangrove ecosystem provides nutrients and energy to nearby seagrass and coral reef ecosystems. ...
... Recently, global developments led to increase of anthropogenic stresses affecting coastal ecosystems particularly mangroves ecosystem [8,13]. Around 62% of mangroves worldwide have been lost in the last 16 years (2000 -2016), it is around 3-5 times the rate of terrestrial forest loss [14,15,16,30]. ...
Conference Paper
Full-text available
Global mangrove area, especially in Indonesia is continued to decrease up to 2% y-1 over the past few decades. One of the most common strategies to restore degraded mangrove areas is mangrove planting. The objective of this study is to assess current conditions of mangroves and to evaluate mangrove planting. The study revealed that about 75% of mangrove in the study sites was degraded (poor and moderate condition) and only 25% of mangrove was healthy. Questionnaire and interview survey across Indonesia showed that a large number of funds (up to USD 71,443 per location) and effort were invested in mangrove planting, as indicated by project cost, planting area, and number of seed/propagules planted. However, about 79% of mangrove planting was not successful. It was indicated by low seed/propagules survival and low long-term mangrove area increase. In addition, the restoration often did not have proper land preparation, regular maintenance and monitoring, and mangrove seed/propagules are fully depend on nature and seasonal. Vegetative propagation (cutting) experiment in this study showed that true mangrove species were not successfully planted using the conventional vegetative technique. Only some associate mangroves can be planted using the vegetative technique with a survival rate between 40 – 90% and growth rate of 3 – 6 cm month-1. Given most of mangrove was degraded and generally, mangrove planting was not successful, a better restoration and rehabilitation approach is crucial to ensure the success of mangrove restoration program.
... Species-specific dieback was observed by Duke et al. (2005) in Queensland, northeastern Australia affecting 30km² of mangrove in five separate estuaries. Between 1980and 2000Duke et al. (2007 reported a 16% loss in the region. Overall, there was an average of 0.8% habitat decline per year within the distribution of the A. marina (Duke et al., 2007). ...
... Between 1980and 2000Duke et al. (2007 reported a 16% loss in the region. Overall, there was an average of 0.8% habitat decline per year within the distribution of the A. marina (Duke et al., 2007). ...
Full-text available
... Together with the impact of climate change, they are subjected to strong pressures related to aquaculture, agriculture, logging and coastal urban development. This has led to a deforestation of over a third of the surface area of mangrove forests over a decade (Duke et al., 2007). ...
This study examines the participation of minors in fishing activities in the communities settled in the mangroves of the Gulf of Fonseca, in Honduras. With a survey of 88 fishermen from San Lorenzo (in the province of Valle), we describe the perception of adults regarding the involvement of minors in fishing and we examine the threats to the mangrove ecosystem on the Pacific coast. To complete the case study, 11 qualitative interviews and 2 focus groups with key informants were conducted. The results revealed that children start to perform pre-work activities around the age of 11 or 12. The contact with nature in complementary shellfish harvesting and fishing activity is perceived as contributing to the improvement of their understanding of nature in general and about the ecosystem services of the mangrove in particular. This assessment of child labour practices when minors collaborate in family subsistence activities, highlights the need to ensure local traditional knowledge transmission that should be integrated as part of formal education, which may help reinforce the fishing community future implication in conservation bottom-up initiatives at the same time that prevent child labour malpractices.
... Despite the critical importance of mangroves, they are disappearing at an alarming rate around the world with a documented loss of at least 35 percent reportedly linked to human development, industrial activity, climate change and aquaculture (Alongi, 2002;Duke et al., 2007). Such loss has also been reported to have exceeded the disappearance rate of tropical rainforests (Rideout et al., 2013, DasGupta andShaw, 2013;Daru et al., 2013 andRahman et al., 2013). ...
Full-text available
Wetland ecosystems are very important natural environmental resource that forms part of the total wealth of a nation. The Asarama wetland in Andoni is amongst the important wetlands in coastal marine cosystems of the Niger Delta; fascinated by diverse rich biodiversity, wetland ecotypes of mangrove, mudflat, Nypa, estuary and fresh water forest habitats with range of critical ecosystem services they provide for mankind survival. The data gathering involved both primary and secondary sources of information. Result revealed diverse ecological scenarios: a livelihood system with diverse level of significant sources and benefit of the ecosystem services. Food, aquacultural practices and sea route logistic component of livelihood benefit from sources recorded significant (HS-4) level of provisioning services, breeding / nursery benefit with high significant (HS-4) level of supporting services among other levels recorded in Table 1. Ecological challenges revealed nypa palm invasion of the mangrove ecotypes and uncertainty of climatic relationship to hydrological tidal regime as natural scenarios; economic, social, institutional and infrastructural challenges as anthropogenic scenarios. Therefore a policy framework (legislature) as part of future directive and initiatives to enforce the practice of biodiversity priorities and sustainable livelihood is of immediate importance to Asarama-Andoni wetlands ecosystem.
... Hutan mangrove tersebar di perbatasan antara perairan dan lingkungan terestrial di iklim tropis dan subtropis. Mangrove mendukung berbagai jasa ekosistem (ecosystem service) khususnya di habitat pesisir dan laut, termasuk terumbu karang, dan padang lamun [3][4]. Luasan mangrove di perairan Indonesia dalam wilayah laut Indo-Pasifik Barat semakin berkontribusi terhadap keanekaragaman hayati negara [1,5] Hutan mangrove di Indonesia tersebar di 34 provinsi, dengan wilayah utama tersebar di wilayah Indonesia Timur. ...
Technical Report
Full-text available
Indonesia merupakan negara kepulauan yang terdiri lebih dari 17.504 pulau dan menjadi negara dengan kawasan hutan mangrove terbesar di dunia, terdiri dari 2,7 juta ha pada yahun 2020 [1]. Meski hanya menempati 1,3% dari luas permukaan bumi, mangrove ekosistem di seluruh dunia adalah rumah bagi 10% tanaman berbunga, 12% dari mamalia, 16% reptil dan amfibi, 17% burung, dan 35% ikan [2]. Hutan mangrove tersebar di perbatasan antara perairan dan lingkungan terestrial di iklim tropis dan subtropis. Mangrove mendukung berbagai jasa ekosistem (ecosystem service) khususnya di habitat pesisir dan laut, termasuk terumbu karang, dan padang lamun [3-4]. Luasan mangrove di perairan Indonesia dalam wilayah laut Indo-Pasifik Barat semakin berkontribusi terhadap keanekaragaman hayati negara [1,5]. Hutan mangrove di Sumatera Utara, Indonesia meliputi 50.369,8 ha di pesisir timur Pulau Sumatera dan umumnya tumbuh subur di Langkat, Deli Serdang, Batubara, Tanjung Balai, Asahan, Labuhan batu sampai Serdang Bedagai [6]. Di Kabupaten Langkat, mangrove telah hilang lebih dari 52% selama pengamatan tahun 1990-2015 [6]. Hutan mangrove sebagai pengganti budidaya perikanan dan perkebunan kelapa sawit merupakan pendorong utama deforestasi di Langkat [7-8]. Sementara hutan mangrove terancam, baik karena aktivitas manusia, pemanasan global atau degradasi air, hutan mangrove adalah salah satu ekosistem yang mampu berkontribusi pada pencapaian beberapa tujuan pembangunan berkelanjutan (SDG). Pengakuan nilai tinggi hutan mangrove dan beragam jasa ekosistem yang mereka berikan telah memotivasi investasi dalam upaya restorasi di seluruh dunia [9]. Namun, metrik restorasi fungsional saat ini (selain tingkat kelangsungan hidup bibit dan komposisi komunitas tumbuhan) seringkali tidak tersedia untuk pengelola komunitas lokal, menyoroti urgensi untuk mengidentifikasi indikator yang mudah diukur untuk menilai fungsionalitas mangrove yang direstorasi [9]. Hutan mangrove menyediakan habitat yang berkelanjutan bagi banyak spesies ikan dan kerang. Menangkap dan menjual spesies ini adalah cara untuk menghasilkan pendapatan dan mengurangi kemiskinan (SDG 1). Bioprospecting adalah eksplorasi bahan bioresources untuk produk-produk turunan mangrove yang bermanfaat (SDG 2). Ikan dan krustasea tertarik ke hutan mangrove karena ketersediaan makanan yang luas, perairan yang lebih sejuk dan keamanan yang dapat ditemukan di antara akar (SDG 13). Hutan mangrove adalah rumah bagi berbagai keanekaragaman hayati, termasuk beberapa spesies mamalia dan reptil dan setidaknya 200 spesies burung, termasuk spesies yang terancam punah (SDG 15).
... In particular the last century has seen an increase of deforestation in previously untouched ecosystems, with the prime example being the amazonian forest. Similarly, mangrove forests, which are inter-tidal forests occurring along tropical, subtropical, and some temperate coasts have been experiencing equal or greater rates of deforestation (Duke et al., 2007;Richards and Friess, 2016). Despite this fact, the issue of mangrove degradation and deforestation has received comparatively little attention (Friess et al., 2019). ...
Full-text available
Deforestation is a matter of pressing global concern, contributing to declining ecosystem services, biodiversity loss, and ultimately climate change through growing emissions. We evaluate the effect of assigning property rights to indigenous peoples and local communities (IPLCs) in coastal Ecuador on deforestation and the role polycentric institutions play in policy effectiveness. Informed by a theoretical model, we employ causal methods to 1) evaluate changes in forest coverage for the first 12 years of policy adoption, and 2) evaluate the effect of the presence of non-governmental organizations (NGOs) on policy permanence. We find that assigning property rights to IPLCs significantly decreases mangrove deforestation and that the presence of NGOs funded by foreign aid significantly increases the probability of policy adoption and permanence. We assess the positive development implications of the policy concerning local fisheries provisioning and the role of international aid in achieving environmental outcomes. Our work highlights the importance of IPLCs and civil society as actors for sustainable land stewardship in future climate policy.
... As an essential ecosystem, mangroves are important as a buffer zone and coastline protection [9,10], nutrient supply [11], habitats for terrestrial and marine flora and fauna such as fish, crustaceans [12,13], ecotourism, and also as a spawning and nursery ground some species of crustaceae which have high economic value [14][15][16][17]. Economic values and benefits of mangroves can be determined directly or indirectly [18]. ...
Conference Paper
Mangrove is one of the essential ecosystems that absorb carbon most productively and efficiently compared to other ecosystems. Carbon is important to maintain the balance of mangrove ecosystem. However, mangrove carbon content varies depending on the formation of sediment, thickness, and plant composition. The objectives of this study are to assess soil carbon content at various types of mangroves communities and land use in Segara Anakan. Fifty-Eight plots (size of 30 x 10 m2) were selected to determine the carbon storage in the dense mangrove (M1), moderate mangrove (M2), planted mangrove (MT), Derris (D), Nypa (N), Rice fields (S), Shrub (LT), and Terrestrial vegetation (V). Mangrove substrates were taken using an auger in the plots at five ranges of depth. The results showed that the highest carbon and water content wereas found in planted mangroves, followed by dense mangroves. The lowest water content was in paddy fields and terrestrial vegetation, while for carbon content the lowest was found in the shrub. The carbon content of the dense mangrove and planted mangrove were in the range of 4.57 ± 0.85 - 6.07 ± 1.18% and 5.02 ± 0.80 - 7.45 ± 0.61%, respectively.
Tropical mangroves, one of the most important blue-carbon ecosystems, are among the world’s most threatened ecosystems and are in danger of disappearing within the next century, which may have a significant impact on coastal ecology and biodiversity, and also on the global capacity of climate change mitigation. The Caribbean region is one of the main mangrove hotspots on Earth. This paper is a thorough updated synthesis on the origin, evolutionary turnover, diversification and historical decline of the Caribbean mangroves, in relation to tectonic, climatic, eustatic and anthropogenic shifts. Neotropical mangroves originated in the Caribbean during the Middle Eocene, after the emergence of the first known mangrove-forming tree (Pelliciera). The abrupt cooling and sea-level fall of the Eocene-Oligocene transition (EOT) would have facilitated the replacement of the primeval mangroves by others dominated by Rhizophora. This was a major evolutionary disruption and gave rise to the modern Neotropical mangrove forests, still dominated by Rhizophora, with Pelliciera restricted to a relictual equatorial patch. The other extant mangrove-forming trees (Avicennia, Pelliciera) appeared in the Mio-Pliocene and the main diversification burst occurred in the Plio-Pleistocene, when 80% of extant genera emerged, with no extinctions documented. Pleistocene climatic and eustatic glacial cycles promoted recurrent spatial and compositional reorganizations. Natural drivers were the most influential until the Middle Holocene, when Amerindian cultures settled the whole Caribbean region and began to modify mangrove communities for agriculture and other activities using fire. During the last decades, deforestation has accelerated and the Caribbean mangrove cover has been reduced by >30%. A variety of conservation actions have been undertaken, but paleoecological and evolutionary knowledge remains to be fully incorporated into mangrove preservation. It is hoped that contributions like the present will help raising awareness on the importance of past records for conservation purposes.
Full-text available
This book covers key areas of geography, environment and earth sciences. The contributions by the authors include bioplastic, industrial waste, agricultural waste, biodegradable materials, petroleum-based plastics, tensile energy, solubility, spray drying, water activity, water absorption index, water solubility index, tidal resonance, quarter-wavelength theory, Taylor method, topography effect, large semidiurnal lunar amplitudes, anti-nodal bands, urban design, carbon management, ecosystem services, land use and land cover, agro ecosystem, biodiversity loss, mangrove degradation, ponds conversion. This book contains various materials suitable for students, researchers and academicians in the field of geography, environment and earth sciences.
Full-text available
The goods and services that mangrove forests provide to society are widely understood but may be too generally stated to serve as useful guidelines in decision-making. Understanding the differences between fringe, riverine, and basin forests may help to focus these guidelines and to determine the best use of a particular forest. Fringe mangroves are important primarily for shoreline protection. Riverine forests, which are likely to be the most productive of the three types of forests, are particularly important to animal and plant productivity, perhaps because of high nutrient concentrations associated with sediment trapping. Basin forests serve as nutrient sinks for both natural and anthropogenically enhanced ecosystem processes and are often important sources of wood products. Exploitation of a forest for one particular reason may make it incapable of providing other goods and services.
Full-text available
Mangroves, the only woody halophytes living at the confluence of land and sea, have been heavily used traditionally for food, timber, fuel and medicine, and presently occupy about 181 000 km2 of tropical and subtropical coastline. Over the past 50 years, approximately one-third of the world's mangrove forests have been lost, but most data show very variable loss rates and there is considerable margin of error in most estimates. Mangroves are a valuable ecological and economic resource, being important nursery grounds and breeding sites for birds, fish, crustaceans, shellfish, reptiles and mammals; a renewable source of wood; accumulation sites for sediment, contaminants, carbon and nutrients; and offer protection against coastal erosion. The destruction of mangroves is usually positively related to human population density. Major reasons for destruction are urban development, aquaculture, mining and overexploitation for timber, fish, crustaceans and shellfish. Over the next 25 years, unrestricted clear felling, aquaculture, and overexploitation of fisheries will be the greatest threats, with lesser problems being alteration of hydrology, pollution and global warming. Loss of biodiversity is, and will continue to be, a severe problem as even pristine mangroves are species-poor compared with other tropical ecosystems. The future is not entirely bleak. The number of rehabilitation and restoration projects is increasing worldwide with some countries showing increases in mangrove area. The intensity of coastal aquaculture appears to have levelled off in some parts of the world. Some commercial projects and economic models indicate that mangroves can be used as a sustainable resource, especially for wood. The brightest note is that the rate of population growth is projected to slow during the next 50 years, with a gradual decline thereafter to the end of the century. Mangrove forests will continue to be exploited at current rates to 2025, unless they are seen as a valuable resource to be managed on a sustainable basis. After 2025, the future of mangroves will depend on technological and ecological advances in multi-species silviculture, genetics, and forestry modelling, but the greatest hope for their future is for a reduction in human population growth.
Full-text available
Numerous factors affect the distribution of mangrove plants. Most mangrove species are typically dispersed by water-buoyant propagules, allowing them to lake advantage of estuarine, coastal and ocean currents both to replenish existing stands and to establish new ones. The direction they travel depends on sea currents and land barriers, but the dispersal distance depends on the time that propagules remain buoyant and viable. This is expected to differ for each species. Similarly, each species will also differ in establishment success and growth development rate, and each has tolerance limits and growth responses which are apparently unique. Such attributes are presumably responsible for the characteristic distributional ranges of each species, as each responds to the environmental, physical and biotic settings they might occupy. In practice, species are often ordered by the interplay of different factors along environmental gradients, and these may conveniently be considered at four geographic scales-global, regional, estuarine and intertidal. We believe these influencing factors act similarly around the world, and to demonstrate this point, we present examples of distributional gradients from the two global biogeographic regions, the Atlantic East Pacific and the Indo-West Pacific.
Full-text available
Although it is widely thought to influence ecosystem processes, there is little consensus on an appropriate measure of functional diversity. The two major perspectives, to date, are to assume that every species is functionally unique, or to assume that some species are functionally identical, such that functional groups exist. Using a continuous measure of functional diversity (FD) derived from the quantitative functional traits of species, we show that the loss of functional diversity from six natural assemblages was rapid compared with rates of loss from comparable simulated assemblages. Loss of FD occurred faster than loss of functional-group diversity in four of the six natural assemblages. Patterns of functional-group diversity loss depended on the number of functional groups and the number of species in an assemblage. Extinctions that occurred first for species with particular traits (e.g. low leaf nitrogen concentration, deep roots and large body size) caused greater loss of FD than expected by chance in four of the six natural assemblages. In two real assemblages, these trait-dependent extinctions had more severe effects on FD than our simulated worst-case extinction scenario. These data suggest that conserving a large proportion of the functional traits of species requires conserving a large proportion of all species.
Summary • We measured sediment elevation and accretion dynamics in mangrove forests on the islands of Guanaja and Roatan, Honduras, impacted by Hurricane Mitch in 1998 to determine if collapse of underlying peat was occurring as a result of mass tree mortality. Little is known about the balance between production and decomposition of soil organic matter in the maintenance of sediment elevation of mangrove forests with biogenic soils. • Sediment elevation change measured with the rod surface elevation table from 18 months to 33 months after the storm differed significantly among low, medium and high wind impact sites. Mangrove forests suffering minimal to partial mortality gained elevation at a rate (5 mm year−1) greater than vertical accretion (2 mm year−1) measured from artificial soil marker horizons, suggesting that root production contributed to sediment elevation. Basin forests that suffered mass tree mortality experienced peat collapse of about 11 mm year−1 as a result of decomposition of dead root material and sediment compaction. Low soil shear strength and lack of root growth accompanied elevation decreases. • Model simulations using the Relative Elevation Model indicate that peat collapse in the high impact basin mangrove forest would be 37 mm year−1 for the 2 years immediately after the storm, as root material decomposed. In the absence of renewed root growth, the model predicts that peat collapse will continue for at least 8 more years at a rate (7 mm year−1) similar to that measured (11 mm year−1). • Mass tree mortality caused rapid elevation loss. Few trees survived and recovery of the high impact forest will thus depend primarily on seedling recruitment. Because seedling establishment is controlled in large part by sediment elevation in relation to tide height, continued peat collapse could further impair recovery rates. Journal of Ecology (2003) 91, 1093–1105
Macroecology is an emerging subdiscipline within ecology that explores effects of large-scale processes on local, regional, and global patterns of species diversity and taxon-independent scaling of structural and functional relationships. Statistical analysis of these patterns yields hypotheses concerning the processes determining population, community, and ecosystem-level patterns, which have been the historical focus of most ecological research, including that done in mangroves. The majority of studies of mangrove forests have aimed to better understand the causes of local (within-forest) ecological patterns (e.g. zonation, tolerance to salinity and hypoxia, litterfall and production), with little attention to the larger environmental, historical and evolutionary contexts that can influence local processes. I argue that a focus on the larger-scale contexts that constrain local processes (a "macroecology of mangroves") will provide us with new insights into the structure and function of mangrove ecosystems. Further, such analyses can be used to determine if mangroves follow similar general rules that have been identified for upland forested ecosystems. I consider two examples: relationships between local species richness and latitude, longitude and regional diversity; and structural coordination of leaf traits. I present data and analyses of these macroecological patterns in mangrove forests, and illustrate points of agreement and disagreement between these and upland ecosystems. I suggest that ecological theory developed in upland forests can be readily applied to mangrove forests. Such a conclusion should lead to advances in ecological research of mangroves and better predictions of how they will respond to global climate change.
KHURA BURI, THAILAND-- Besieged by pathogens, predators, and people, the "rainforests of the sea" may soon face their ultimate foe: rising ocean acidity driven by carbon dioxide emissions. (Read more.)
Whether or not mangroves function as buffers against tsunamis is the subject of in-depth research, the importance of which has been neglected or underestimated before the recent killer tsunami struck. Our preliminary post-tsunami surveys of Sri Lankan mangrove sites with different degrees of degradation indicate that human activity exacerbated the damage inflicted on the coastal zone by the tsunami.
This paper explores two methods for valuing ecosystems by valuing the services that they yield to various categories of user and that are not directly valued in the market, and illustrates the usefulness of these methods with an application to the valuation of mangrove ecosystems in Thailand. The first method is known as the production function approach and relies on the fact that ecosystems may be inputs into the production of other goods or services that are themselves marketed, such as fisheries. I discuss issues that arise in measuring the input into fisheries, particularly those due to the fact that the fishery stock is changing over time, and the shadow value of the ecosystem consists in its contribution to the maintenance of the stock as well as its contribution to current output. The second method is known as the expected damage approach and is used to value the services of storm protection in terms of the reduction in expected future storm damage that the ecosystem can provide. These two methods are shown to yield very different valuations of ecosystems from those that would be derived by the methods typically used in cost-benefit analyses. I argue that they represent a significant improvement on current practice. — Edward B. Barbier