Ecosystem with more species function better<\/p>\n
By Nick Mawdsley<\/p>\n
JAKARTA (JP): Three years ago, a unique meeting organized by
\nthe United Nations in Rio de Janiero, Brazil produced commitment
\nfrom 157 of the world's governments to implement policies to
\nachieve sustainable development through the signing of the
\nconvention on biodiversity.<\/p>\n
This week Jakarta hosted the Second Meeting of the Parties to
\nthe Convention of biodiversity where governments reviewed
\nimplementation of conventions and addressed major scientific and
\ntechnical issues to achieve the highly desirable goal of the
\nsustainable use and conservation of biodiversity.<\/p>\n
But just how much do scientists know about biodiversity and
\nits impacts on the world in which we live? More importantly, what
\ndo we need to know?<\/p>\n
The Global Biodiversity Forum, a companion meeting to the
\nconference and itself organized by a diverse array of
\norganizations was held prior to the conference. The forum
\nprovided an opportunity for interested parties to air their views
\non what exactly are the major issues relating to action required
\nto save and use biodiversity.<\/p>\n
Forests hold much of the world's biodiveristy, and in a
\nworkshop organized by the Bogor-based Center for International
\nForest Research, forest scientists and conservationists
\nhighlighted the need for greater information on the diversity and
\ndistribution of forest species. Without this basic information,
\nconservation planning and the selection of protected areas simply
\ncannot be achieved.<\/p>\n
Birds are perhaps the most well-known and best studied of all
\ngroups, and Paul Jepson of the Birdlife International Indonesia
\nProgram illustrated how the protected areas network in Indonesia
\nmay be successfully improved through the establishment of
\nproposed protected areas in Maluku, selected using knowledge of
\nthe global distribution of bird biodiversity.<\/p>\n
Protected areas such as national parks are just one approach
\nto conservation, but with most land in much of Indonesia and
\nelsewhere being under agriculture and plantations, biologists and
\nconservationists are focusing on the potential biodiversity value
\nof these managed lands.<\/p>\n
The vast, open landscapes of rice fields and modern single-
\nspecies tree plantations present perhaps the extremes of low
\nbiodiversity value. Dr. Meine van Noordwijk from the
\nInternational Center for Research in Agro-Forestry in Bogor
\nshowed the forum participants how other forms of land management
\nmay preserve at least some biodiversity.<\/p>\n
The center's researchers found that traditionally managed
\nrubber, durian and damar \"agro-forests\" do support a significant
\nproportion of forest species. Van Noordwijk suggested to the
\nforum that in some circumstances it might be better to integrate
\nconservation with agricultural production rather than segregate
\nthe two.<\/p>\n
Critical to this approach of integrating conservation and
\nagriculture is that agricultural methods become more
\nenvironmentally friendly using less fertilizer, less pesticides
\nand less extensive clearing of land, while maintaining adequate
\nyields.<\/p>\n
The recovery of certain species in the British agricultural as
\na result of less intense agricultural practices serves as a
\nlesson of how seemingly poor areas can be revived and made
\nvaluable for nature conservation. Perhaps the largest area of
\nuncertainty concerning the conservation of forest biodiversity
\nraised by participants at the forum concerned the functional
\nsignificance of species.<\/p>\n
What exactly do species do, and do we need to conserve all
\nspecies to keep ecosystems functioning properly? Ecosystem are no
\ndifferent to towns and cities and their functioning depends on
\nwater supply and flow, production of food through plant growth,
\ndecomposition of waste materials and the renewal of nutrients. In
\ntheir totality these ecosystem functions enable natural and human
\necosystems to persist.<\/p>\n
But prior to the 1980s, the significance of the variety of
\nspecies to the functioning of ecosystems was barely considered.
\nBut then ecologists started to collect data and the answers they
\nfound were surprising.<\/p>\n
At Imperial College in England, ecologists led by Prof. John
\nLawton create simple ecosystems using plants, insects and other
\ninvertebrates commonly found in Britain. The ecosystems are
\nmonitored by the researchers who make detailed measurements of
\nhow each system functions together.<\/p>\n
Contrary to the widespread belief that many species are
\n\"redundant\" to the function of ecosystems, the Imperial
\nresearchers found that the ecosystems with more species
\nfunctioned better. Support for this unexpected result came soon
\nafter from observations of North American grasslands carried out
\nby Prof. David Tilman. Tilman and his team found that grasslands
\nwith most species were most resilient to a sudden and severe
\ndrought. Again, it appeared that ecosystems with more species
\nwere functionally better.<\/p>\n
What then does this tell us about the most diverse ecosystems
\non land, the tropical rain forests?<\/p>\n
A single hectare of undisturbed lowland forest in Indonesia may
\nbe home to over 200 tree species, and be used by up to 200
\nspecies of birds and 30,000 insect species -- more than are
\npresent in the whole of Britain.<\/p>\n
Do all these species contribute to the functioning of tropical
\nforests? Dr. Steve Compton from the University of Leeds said: \"My
\nguess is that although tropical forests are complex, they
\nprobably have a small proportion of species that are particularly
\ncritical to their functioning. With the degradation of forests,
\nwhat is important in the long-term may not be the absolute number
\nof species retained, but whether the system contains these
\nkeystone species or not.\" Indeed it appears that keystone species
\ndo exists in some forests.<\/p>\n
During periods of fruit scarcity in South America, fig trees
\nand palm nuts support populations of fruit-eating birds and mammals.
\n\"Clearly if we lose the figs and palm nuts we may lose many
\nspecies that depend upon them,\" said Compton. \"The consequences
\nfor the forest of not having fruit-eaters is that seeds will not
\nbe dispersed, which in turn may lead to a breakdown in the
\necosystem.\"<\/p>\n
Such a drastic possibility demands identification and action to
\nconserve these keystone species, particularly as in many areas the
\nbreakdown in ecosystem function may already have started.<\/p>\n
Conservation managers and policy makers have the difficult task
\nof deciding the value of the less important species, but these
\nthemselves may be valuable insurance policy in buffering
\necosystems against an unpredictably changing world. Despite these
\nconcerns, the ultimate goal of conservation must be preservation
\nof the diversity of life.<\/p>\n
As Prof. Lawton noted, \"a species poor sanitized world may
\nwork very well, but without wild orchids and orpendulas,
\ntardigrades and tigers, humankind will be the loser.\"<\/p>\n
The writer is a professor at University of Leeds, England.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/ecosystem-with-more-species-function-better-1447893297", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }