Identifying Target Species and Seed Sources for the Restoration of Threatened Trees in Southern Brazil

Identifying target species and seed sources for the restoration of threatened trees in southern Brazil P. M. HOFFMANN,C.T.BLUM,S.J.E.VELAZCO,D.J.C.GILL and M . B ORGO Abstract Ecological restoration of trees is often constrained Targets have been set to restore % of degraded land by by limited knowledge of the biology, propagation and man- (CBD, ) but restoration efforts are often con- agement requirements of individual species. Consequently, strained by lack of knowledge of the biology, propagation restoration initiatives rarely incorporate less well-known and management of tree species or by a lack of sufficient species or those that are difficult to source and grow. We de- seed (Merritt & Dixon, ). A reliable source of high- scribe challenges associated with the restoration of threa- quality seed is critical to the success of restoration projects, tened trees in the Araucaria Forest of southern Brazil, and directly influencing the germination and survival of seed- analyse the effectiveness of methods used to define target lings and the genetic diversity of populations (Zahawi & species, identify seed sources and generate information on Holl, ). the phenology of rare or threatened tree species. A review These challenges are particularly pertinent to the of secondary data identified rare or threatened taxa as tar- Brazilian Atlantic Rainforest, a biodiversity hotspot gets for seed collection. We then surveyed . km of trails (Myers et al., ) with ., plant species and , in forest remnants, identifying and mapping , seed- animal species interacting across multiple trophic levels producing trees of species. Surveys confirmed the scarcity (Mittermeier et al., ; Ribeiro et al., ). Less than of several tree species (including seven species with an abun- % of the forest remains, in isolated remnants, many of dance of ,. individuals per km), and nine species which are highly degraded (Ribeiro et al., ). Attempts showed no signs of fruiting during years of phenological to restore the biome have evolved from projects focusing monitoring. These findings, together with limited knowl- on a small number of fast-growing species (most of which edge and application of optimal seed collection methods, failed to establish into self-perpetuating forest; Barbosa are significant factors impeding the recovery of these species et al., ) to initiatives adopting a high-diversity planting within their natural habitat. Wider application of the results approach (e.g. planting – tree species; Rodrigues et al., of this case study could support restoration of the Araucaria ). For many tree species, however, a lack of information Forest with seedlings from a wider diversity of species. on their reproductive biology prevents their inclusion in restoration projects (Rodrigues et al., ). Keywords Araucaria Forest, Brazil, conservation, phe- The Araucaria Forest is one of the most threatened eco- nology, propagation, seed collection, subtropical forest res- systems in the Atlantic Rainforest biome. In Paraná state, toration, threatened species where Araucaria Forest was once the dominant vegetation This paper contains supplementary material that can be type, covering ,, ha (Maack, ), ,.% of the orig- found online at http://journals.cambridge.org inal forest remains in advanced successional stages, none of which is considered primary forest (Castella & Britez, ). Such extensive fragmentation means that areas left to regen- erate without human assistance never attain the full range of naturally occurring species (Liebsch et al., ). Introduction Restoration is the main mechanism available to restore he restoration of damaged but previously complex eco- species richness in the Araucaria Forest, but seed collection Tsystems may be one of the greatest challenges facing and tree planting tend to be focused on a narrow range of tropical forest conservation (Rojas-Briales & Weise, ). species. Partly as a result of low seed collection effort, only of the tree species found in Araucaria Forest (Leite & Klein, ) have been cultivated by Paraná state nurseries, which are the main producers of seedlings for restoration of this ecosystem (Martins et al., ). It is common practice P. M. HOFFMANN (Corresponding author), S. J. E. VELAZCO and M. BORGO Sociedade Chauá, 82130-010, Curitiba, Brazil. E-mail [email protected] to produce seedlings of species that are easy to collect, fast-growing or technically simple to grow, rather than C. T. BLUM Departamento de Ciências Florestais, Universidade Federal do Paraná, Curitiba, Brazil many native species for which there is a lack of information D. J. C. GILL Fauna & Flora International, Cambridge, UK on seed collection and germination protocols. Only %of Received June . Revision requested August . the threatened species of the Araucaria Forest have been Accepted November . First published online March . grown by state nurseries (Martins et al., ). In cases Oryx, 2015, 49(3), 425–430 © 2015 Fauna & Flora International doi:10.1017/S0030605314001069 Downloaded from https://www.cambridge.org/core. IP address: 170.106.202.8, on 02 Oct 2021 at 04:29:18, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605314001069 426 P. M. Hoffmann et al. precipitation is ,–, mm (IAPAR, ). This subtropical forest is characterized by a dense physiognomy, marked by the dominance of emergent Araucaria angustifo- lia trees, with a mean height of – m (Scheer & Blum, ). Methods A list of target species for seed collection was identified, including all threatened or rare tree species. Threatened species were defined as those listed in the regional, national or global Red Lists (SEMA, ; MMA, ; IUCN, ), including species categorized as Near Threatened. The threat categories of the various Red Lists were standardized ac- cording to IUCN (). Rare species were defined as those not included in official Red Lists but with few herbarium records (INCT, ) and a low frequency of occurrence, identified through surveys of the structure of the FIG. 1 Original distribution of Araucaria Forest in Paraná, Brazil Araucaria Forest (Durigan, ; Pasdiora, ; Barddal (adapted from Olson et al., ). The rectangle on the inset et al., ; Geraldi et al., ; Seger et al., ; indicates the location of the main map in Brazil. Watzlawick et al., ; Kozera et al., ; Cordeiro & Rodrigues, ; Cordeiro, ). A list of potential forest remnants was developed based where nurseries produce seedlings of threatened species, on the occurrence of at least one target species. Data on seeds are usually collected from a small number of trees, re- the conservation status of these remnants were compiled sulting in low genetic variability and fitness of seedlings based on our knowledge and on a technical report of the sta- (Zahawi & Holl, ). tus of the Araucaria Forest (Castella & Britez, ). Fast-growing species play an important role in the resto- The final selection was based on geographical variability ration process. By developing a canopy layer and encourag- (including various floristic associations within the ing the return of seed dispersers and pollinators they can Araucaria Forest, to maximize genetic variability for each accelerate forest succession and the natural recruitment of species), forest condition (fragments of medium to ad- a wide range of species (Elliott et al., ). However, in de- vanced successional stage, with a minimum size of graded and fragmented landscapes, such as the Araucaria ha), and guarantee of protection (remnants located in pro- Forest, restoration with a low diversity of species is unlikely tected areas or under other forms of conservation manage- to create the conditions necessary for dispersal of a wider ment, thus maximizing the likelihood of selected mother range of naturally occurring species (Rodrigues et al., trees surviving and being available for long-term monitor- ). There is therefore a growing need for government ing and seed collection). agencies and conservation institutions to broaden the Each selected forest remnant was surveyed intensively by focus of seed collection and restoration efforts to include walking along all existing trails to search for mother trees of threatened or locally rare species as well as fast-growing spe- target species. Species were initially identified in the field cies. Here we present a list of target species for conservation and later confirmed by comparison with herbarium spe- and restoration, identify sources of seeds (mother trees), es- cimens. The criteria for selection of mother trees were timate their frequency and abundance, and present basic in- good health (free of damage, disease and infestation by information about phenological patterns of threatened and sects) and full reproductive maturity (tree size, presence of rare species in the Araucaria Forest. old fruits, seeds or seedlings under the tree). We attempted to map the highest number of mother Study area trees in the maximum possible number of remnants. To ob- tain seeds with broad genetic variation, they were collected, The Araucaria Forest once covered the plateau regions in the when possible, from at least three populations of each spe- centre and south of Paraná, at –, m altitude (Fig. ). cies (Nogueira & Medeiros, ), and from at least trees The climate is humid subtropical, with cool summers and per population (Vencovsky, ). When this was not poss- no dry season; frost is common in winter (Peel et al., ible, surveys aimed to identify at least trees per species

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